Title of Invention

NOVEL INHIBITORS OF GLUTAMINYL CYCLASE

Abstract

The present invention relates to compounds of formula (I), combinations and uses thereof for disease therapy, wherein: Rl represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl; R2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, -C(O)O-alkyl and -C(O)OH; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)O-alkyl and -C(O)OH; alkenyl; alkynyl; -alkyl-aryl; -alkyl-heteroaryl; -alkyl-heterocyclyl; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -heteroaryl-heteroaryl; -aryl-aryl; -aryl (monocyclic or bicyclic); heteroaryl (monocyclic or bicyclic); heterocyclyl; or R2 together with R4 may form a carbocyclyl group optionally substituted by one or more alkyl groups; R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O-alkyl; alkenyl; -alkyl- aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -aryl-O-aryl, -heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl-C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH- alkyl-heterocyclyl; -alkyl-C(O)-(N-piperidinyl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. R4 represents H or alkyl.

Full Text

Novel Inhibitors of Glutaminyl Cyclase Field of the invention The invention relates to glutaminyl cyclase (QC, EC 2.3.2.5) that catalyzes the intramolecular cyclization of N-terminal glutamine residues into pyroglutamic acid (5-oxo-prolyl, pGlu*) under liberation of ammonia and the intramolecular cyclization of N-terminal glutamate residues into pyroglutamic acid under liberation of water. Background of the invention Glutaminyl cyclase (QC, EC 2.3.2.5) catalyzes the intramolecular cyclization of N-terminal glutamine residues into pyroglutamic acid (pGlu*) liberating ammonia. A QC was first isolated by Messer from the latex of the tropical plant Carica papaya in 1963 (Messer, M. 1963 Nature 4874, 1299). 24 years later, a corresponding enzymatic activity was discovered in animal pituitary (Busby, W. H. J. et al. 1987 J Biol Chem 262, 8532-8536; Fischer, W. H. and Spiess, J. 1987 Proc Natl Acad Sci U S A 84, 3628-3632). For the mammalian QC, the conversion of Gin into pGlu by QC could be shown for the precursors of TRH and GnRH (Busby, W. H. J. et al. 1987 J Biol Chem 262, 8532-8536; Fischer, W. H. and Spiess, J. 1987 Proc Natl Acad Sci U S A 84, 3628-3632). In addition, initial localization experiments of QC revealed a co-localization with its putative products of catalysis in bovine pituitary, further improving the suggested function in peptide hormone synthesis (Bockers, T. M. et al. 1995 J Neuroendocrinol 7, 445- 453). In contrast, the physiological function of the plant QC is less clear. In the case of the enzyme from C. papaya, a role in the plant defense against pathogenic microorganisms was suggested (El Moussaoui, A. et al.2001 Cell Mol Life Sci 58, 556-570). Putative QCs from other plants were identified by sequence comparisons recently (Dahl, S. W. et al.2000 Protein Expr Purif 20, 27-36). The physiological function of these enzymes, however, is still ambiguous. The QCs known from plants and animals show a strict specificity for L-Glutamine in the N- terminal position of the substrates and their kinetic behavior was found to obey the Michaelis- Menten equation (Pohl, T. et al. 1991 Proc Natl Acad Sci U S A 88, 10059-10063; Consalvo, A. P. et al. 1988 Anal Biochem 175, 131-138; Gololobov, M. Y. et al. 1996 Biol Chem Hoppe Seyler 377, 395-398). A comparison of the primary structures of the QCs from C. papaya and that of the highly conserved QC from mammals, however, did not reveal any sequence homology (Dahl, S. W. et al. 2000 Protein Expr Purif 20, 27-36). Whereas the plant QCs appear to belong to a new enzyme family (Dahl, S. W. et al. 2000 Protein Expr Purif 20, 27-36), the mammalian QCs were found to have a pronounced sequence homology to bacterial aminopeptidases (Bateman, R. C. et al. 2001 Biochemistry 40, 11246-11250), leading to the conclusion that the QCs from plants and animals have different evolutionary origins. Recently, it was shown that recombinant human QC as well as QC-activity from brain extracts catalyze both, the N-terminal glutaminyl as well as glutamate cyclization. Most striking is the finding, that cyclase-catalyzed GlU1-conversion is favored around pH 6.0 while Gln1-conversion to pGlu-derivatives occurs with a pH-optimum of around 8.0. Since the formation of pGlu-Aβ related peptides can be suppressed by inhibition of recombinant human QC and QC-activity from pig pituitary extracts, the enzyme QC is a target in drug development for treatment of Alzheimer's disease. First inhibitors of QC are described in WO 2004/098625, WO 2004/098591, WO 2005/039548 and WO 2005/075436. EP 02 011 349.4 discloses polynucleotides encoding insect glutaminyl cyclase, as well as polypeptides encoded thereby and their use in methods of screening for agents that reduce glutaminyl cyclase activity. Such agents are useful as pesticides. Definitions The terms "Ki" or "Ki" and "KD" are binding constants, which describe the binding of an inhibitor to and the subsequent release from an enzyme. Another measure is the "IC50" value, which reflects the inhibitor concentration, which at a given substrate concentration results in 50 % enzyme activity. The term "DP IV-inhibitor" or "dipeptidyl peptidase IV inhibitor" is generally known to a person skilled in the art and means enzyme inhibitors, which inhibit the catalytic activity of DP IV or DP IV-like enzymes. "DP IV-activity" is defined as the catalytic activity of dipeptidyl peptidase IV (DP IV) and DP IV- like enzymes. These enzymes are post-proline (to a lesser extent post-alanine, post-serine or post-glycine) cleaving serine proteases found in various tissues of the body of a mammal including kidney, liver, and intestine, where they remove dipeptides from the N-terminus of biologically active peptides with a high specificity when proline or alanine form the residues that are adjacent to the N-terminal amino acid in their sequence. The term "PEP-inhibitor" or "prolyl endopeptidase inhibitor" is generally known to a person skilled in the art and means enzyme inhibitors, which inhibit the catalytic activity of prolyl endopeptidase (PEP, prolyl oligopeptidase, POP). "PEP-activity" is defined as the catalytic activity of an endoprotease that is capable to hydrolyze post proline bonds in peptides or proteins were the proline is in amino acid position 3 or higher counted from the N-terminus of a peptide or protein substrate. The term "QC" as used herein comprises glutaminyl cyclase (QC) and QC-like enzymes. QC and QC-like enzymes have identical or similar enzymatic activity, further defined as QC activity. In this regard, QC-like enzymes can fundamentally differ in their molecular structure from QC. Examples of QC-like enzymes are the glutaminyl-peptide cyclotransferase-like proteins (QPCTLs) from human (GenBank NM_017659), mouse (GenBank BC058181), Macaca fascicularis (GenBank AB168255), Macaca mulatta (GenBank XM_001110995), Canis familiaris (GenBank XM_541552), Rattus norvegicus (GenBank XM_001066591), Mus musculus (GenBank BC058181) and Bos taurus (GenBank BT026254). The term "QC activity" as used herein is defined as intramolecular cyclization of N-terminal glutamine residues into pyroglutamic acid (pGlu*) or of N-terminal L-homoglutamine or L-β- homoglutamine to a cyclic pyro-homoglutamine derivative under liberation of ammonia. See therefore schemes 1 and 2. Scheme 1: Cyclization of glutamine by QC The term "EC" as used herein comprises the activity of QC and QC-like enzymes as glutamate cyclase (EC), further defined as EC activity. The term "EC activity" as used herein is defined as intramolecular cyclization of N-terminal glutamate residues into pyroglutamic acid (pGlu*) by QC. See therefore scheme 3. Scheme 3: N-terminal cyclization of uncharged glutamyl peptides by QC (EC) The term "QC-inhibitor" "glutaminyl cyclase inhibitor" is generally known to a person skilled in the art and means enzyme inhibitors, which inhibit the catalytic activity of glutaminyl cyclase (QC) or its glutamyl cyclase (EC) activity. Potency of QC inhibition In light of the correlation with QC inhibition, in preferred embodiments, the subject method and medical use utilize an agent with an IC5o for QC inhibition of 10 uM or less, more preferably of 1 μM or less, even more preferably of 0.1 uM or less or 0.01 uM or less, or most preferably 0.001 μM or less. Indeed, inhibitors with Ki values in the lower micromolar, preferably the nanomolar and even more preferably the picomolar range are contemplated. Thus, while the active agents are described herein, for convenience, as "QC inhibitors", it will be understood that such nomenclature is not intending to limit the subject of the invention to a particular mechanism of action. Molecular weight of QC inhibitors In general, the QC inhibitors of the subject method or medical use will be small molecules, e.g., with molecular weights of 500 g/mole or less, 400 g/mole or less, preferably of 350 g/mole or less, and even more preferably of 300 g/mole or less and even of 250 g/mole or less. The term "subject" as used herein, refers to an animal, preferably a mammal, most preferably a human, who has been the object of treatment, observation or experiment. The term "therapeutically effective amount" as used herein, means that amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue system, animal or human being sought by a researcher, veterinarian, medical doctor or other clinician, which includes alleviation of the symptoms of the disease or disorder being treated. As used herein, the term "pharmaceutically acceptable" embraces both human and veterinary use: For example the term "pharmaceutically acceptable" embraces a veterinarily acceptable compound or a compound acceptable in human medicine and health care. Throughout the description and the claims the expression "alkyl", unless specifically limited, denotes a C1-12 alkyl group, suitably a C1-6 alkyl group, e.g. C1-4 alkyl group. Alkyl groups may be straight chain or branched. Suitable alkyl groups include, for example, methyl, ethyl, propyl (e.g. n-propyl and isopropyl), butyl (e.g n-butyl, iso-butyl, sec-butyl and tert-butyl), pentyl (e.g. n- pentyl), hexyl (e.g. n-hexyl), heptyl (e.g. n-heptyi) and octyl (e.g. n-octyl). The expression "alk", for example in the expressions "alkoxy", "haloalkyl" and "thioalkyl" should be interpreted in accordance with the definition of "alkyl". Exemplary alkoxy groups include methoxy, ethoxy, propoxy (e.g. n-propoxy), butoxy (e.g. n-butoxy), pentoxy (e.g. n-pentoxy), hexoxy (e.g. n- hexoxy), heptoxy (e.g. n-heptoxy) and octoxy (e.g. n-octoxy). Exemplary thioalkyl groups include methylthio-. Exemplary haloalkyl groups include fluoroalkyl e.g. CF3. The expression "alkenyl", unless specifically limited, denotes a C2-12alkenyl group, suitably a C2-6 alkenyl group, e.g. a C2-4 alkenyl group, which contains at least one double bond at any desired location and which does not contain any triple bonds. Alkenyl groups may be straight chain or branched. Exemplary alkenyl groups including one double bond include vinyl (i.e. ethenyl), propenyl and butenyl. Exemplary alkenyl groups including two double bonds include pentadienyl, e.g. (1E, 3E)-pentadienyl. The expression "alkynyl", unless specifically limited, denotes a C2-12alkynyl group, suitably a C2-6 alkynyl group, e.g. a C2-4 alkynyl group, which contains at least one triple bond at any desired location and may or may not also contain one or more double bonds. Alkynyl groups may be straight chain or branched. Exemplary alkynyl groups include ethynyl, propynyl and butynyl. The expression "cycloalkyl", unless specifically limited, denotes a C3.10 cycloaikyl group (i.e. 3 to 10 ring carbon atoms), more suitably a C3-8 cycloalkyl group, e.g. a C3-6 cycloalkyl group. Exemplary cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. A most suitable number of ring carbon atoms is three to six. The expression "cycloalkenyl", unless specifically limited, denotes a C5-10 cycloalkenyl group (i.e. 5 to 10 ring carbon atoms), more suitably a C5-8 cycloalkenyl group e.g. a C5-6 cycloalkenyl group. Exemplary cycloalkenyl groups include cyclopropenyl, cyclohexenyl, cycloheptenyl and cyclooctenyl. A most suitable number of ring carbon atoms is five to six. The expression "carbocyclyl", unless specifically limited, denotes any ring system in which all the ring atoms are carbon and which contains between three and twelve ring carbon atoms, suitably between three and ten carbon atoms and more suitably between three and eight carbon atoms. Carbocyclyl groups may be saturated or partially unsaturated, but do not include aromatic rings. Examples of carbocylic groups include monocyclic, bicyclic, and tricyclic ring systems, in particular monocyclic and bicyclic ring systems. Other carbocylcyl groups include bridged ring systems (e.g. bicyclo[2.2.1]heptenyl). A specific example of a carbocyclyl group is a cycloalkyl group. A further example of a carbocyclyl group is a cycloalkenyl group. The expression "heterocyclyl", unless specifically limited, refers to a carbocyclyl group wherein one or more (e.g. 1, 2 or 3) ring atoms are replaced by heteroatoms selected from N, S and O. A specific example of a heterocyclyl group is a cycloalkyl group (e.g. cyclopentyl or more particularly cyclohexyl) wherein one or more (e.g. 1, 2 or 3, particularly 1 or 2, especially 1) ring atoms are replaced by heteroatoms selected from N, S or O. Exemplary heterocyclyl groups containing one hetero atom include pyrrolidine, tetrahydrofuran and piperidine, and exemplary heterocyclyl groups containing two hetero atoms include morpholine and piperazine. A further specific example of a heterocyclyl group is a cycloalkenyl group (e.g. a cyclohexenyl group) wherein one or more (e.g. 1, 2 or 3, particularly 1 or 2, especially 1) ring atoms are replaced by heteroatoms selected from N, S and O. An example of such a group is dihydropyranyl (e.g. 3,4- dihydro-2H-pyran-2-yl-). The expression "aryl", unless specifically limited, denotes a C6-12 aryl group, suitably a C6-10 aryl group, more suitably a C6-8 aryl group. Aryl groups will contain at least one aromatic ring (e.g. one, two or three rings), but may also comprise partially or fully unsaturated rings. An example of a typical aryl group with one aromatic ring is phenyl. Examples of aromatic groups with two aromatic rings include naphthyl. Examples of aryl groups which contain partially or fully unsaturated rings include pentalene, indene and indane. The expression "heteroaryl", unless specifically limited, denotes an aryl residue, wherein one or more (e.g. 1, 2, 3, or 4, suitably 1, 2 or 3) ring atoms are replaced by heteroatoms selected from N, S and O, or else a 5-membered aromatic ring containing one or more (e.g. 1, 2, 3, or 4, suitably 1, 2 or 3) ring atoms selected from N, S and O. Exemplary monocyclic heteroaryl groups include pyridine (e.g. pyridin-2-yl, pyridin-3-yl or pyridin-4-yl), pyrimidine, pyrrole, furan, thiophene, oxazole, pyrazole, imidazole (e.g. imidazol-1-yl, imidazol-2-yl or imidazol-4-yl), thiazole, isoxazole, pyrazole (e.g. pyrazol-3-yl), triazole (e.g. 1,2,3-triazole or 1,2,4-triazole), tetrazole, pyridazine, pyrazine and isothiazole. Exemplary bicyclic heteroaryl groups include quinoline, benzothiophene, indole (eg. 1H-indol-6- yl), benzimidazole, indazole, purine, chromene, benzodioxolane, benzodioxane (e.g. 2,3- dihydro-benzo[1,4]dioxin-6-yl) and benzodioxepine. The aforementioned aryl and heteroaryl groups may, where appropriate, optionally be substituted by one or more (e.g. 1, 2 or 3, suitably 1 or 2) monovalent or multivalent functional groups. Suitable substituent groups include alkyl, alkenyl, alkynyl, haloalkyl, -thioalkyl (e.g. -thiomethyl), -SO2alkyl (e.g. SO2Me), alkoxy- (e.g. OMe), cycloalkyl, -SO2cycloalkyl, alkenyloxy-, alkynyloxy-, -C(O)-alkyl (e.g. COMe), alkoxyalkyl-, nitro, halogen (e.g. fluoro, chloro and bromo), cyano, hydroxyl, oxo, -C(O)OH, -C(O)Oalkyl (e.g. -C(O)OMe), -NH2, -NHalkyl (e.g. -NHMe), -N(alkyl)2 (e.g. dimethylamino-), -C(O)N(alkyl)2, -C(O)NH2 and -C(O)NH(alkyl). More typically, substituents will be selected from alkyl (e.g. Me), fluoroalkyl (e.g. CF3), alkoxy (e.g. OMe), halogen and hydroxy. Further suitable substituents include -SOalkyl (e.g. SOMe) and -SOcycloalkyl. Another suitable substituent for a heteroaryl group is -C(NH)NH2. Examples of substituted aryl groups therefore include fluorophenyl- (e.g. 4-fluoro-phenyl- or 3- fluoro-phenyl-), pentafluoro-phenyl-, 4-hydroxyphenyl-, 3-nitro-phenyl-, 4-(trifluoromethyl)- phenyl- and 4-anilinyl- groups. Exemplary substituted monocyclic heteroaryl groups include methylfuranyk Exemplary substituted bicyclic heteroaryl groups include chromen-4-one, chromen-2-one and methylbenzothiophenyl. The expression "-alkylaryl", unless specifically limited, denotes an aryl residue which is connected via an alkylene moiety e.g. a C1-4alkylene moiety. Examples of -alkylaryl include: -methylaryl and -ethylaryl (e.g. 1-arylethyl- or 2-arylethyl-); or phenylalkyl-, which may be optionally substituted. Specific examples of -alkylaryl functions include: phenylmethyl- (i.e. benzyl), phenylethyl- (e.g. 2-phenyleth-1-yl or 1-phenyl-eth-1-yl), p-tolyl-methyl-, (p-totyl)-ethyl-, (m-tolyl)-methyl-, (m-tolyl)-ethyl-, (o-tolyl)-methyl-, (o-tolyl)-ethyl-, 2-(4-ethyl-phenyl)-eth-1-yl-, (2,3-dimethyl-phenyl)-methyl-, (2,4-dimethyl-phenyl)-methyl-, (2,5-dimethyl-phenyl)-methyl-, (2,6-dimethyl-phenyl)-methyl-, (3,4-dimethyl-phenyl)-methyl-, β,5-dimethyl-phenyl)-methyl-, (2,4,6-trimethyl-phenyl)-methyl-, (2,3-dimethyl-phenyl)-ethyl-, (2,4-dimethyl-phenyl)-ethyl-, (2,5- dimethyl-phenyl)-ethyl-, (2,6-dimethyl-phenyl)-ethyl-, (3,4-dimethyl-phenyl)-ethyl-, β,5-dimethyl- phenyl)-ethyl-, (2,4,6-trimethyl-phenyl)-ethyl-, (2-ethyl-phenyl)-methyi-, β-ethyl-phenyl)-methyl-, (4-ethyl-phenyl)-methyl-, (2-ethyl-phenyl)-ethyl-, β-ethyl-phenyl)-ethyl-, (4-ethyl-phenyl)-ethyl-, 2-fluoro-benzyl, (1-methyl-2-fluoro-phen-6-yl)-methyl-, (1-methyl-2-fluoro-phen-4-yl)-methyl-, (1- methyl-2-fluoro-phen-6-yl)-ethyl-, (1-methyl-2-fluoro-phen-4-yl)-ethyl-, 1 H-indenyl-methyl-, 2H- indenyl-methyl-, 1 H-indenyl-ethyl-, 2H-indenyl-ethyl-, indanyl-methyl-, indan-1-on-2-yl-methyl-, indan-1-on-2-yl-ethyl-, tetralinyl-methyl-, tetralinyl-ethyl-, fluorenyl-methyl-, fluorenyl-ethyl-, dihydronaphthalinyl-methyl-, dihydronaphthalinyl-ethyl-, or (4-cyclohexyl)-phenyl-methyl-, (4- cyclohexyl)-phenyl-ethyl-. The expression "-alkylheteroaryl", unless specifically limited, denotes a heteroaryl residue which is connected via an alkylene moiety e.g. a C1-4alkylene moiety. Examples of -alkylheteroaryl include -methylheteroaryl and -ethylheteroaryl (e.g. 1-heteroarylethyl- and 2-heteroarylethyl-). Specific examples of-alkylheteroaryl groups include pyridinylmethyl-, N-methyl-pyrrol-2-methyl-, N-methyl-pyrrol-2-ethyl-, N-methyl-pyrrol-3-methyl-, N-methyl-pyrrol-3-ethyl-, 2-methyl-pyrrol-1 - methyl-, 2-methyl-pyrrol-1-ethyl-, 3-methyl-pyrrol-1-methyl-, 3-methyl-pyrrol-1 -ethyl-, 4-pyridino- methyl-, 4-pyridino-ethyl-, 2-(thiazol-2-yl)-ethyl-, 2-ethyl-indol-1-methyl-, 2-ethyl-indol-1-ethyl-, 3- ethyl-indol-1 -methyl-, 3-ethyl-indol-1 -ethyl-, 4-methyl-pyridin-2-methyl-, 4-methyl-pyridin-2-yl- ethyl-, 4-methyl-pyridin-3-methyl-, 4-methyl-pyridin-3-ethyl-. The expression "-alkyl(aryl)2", unless specifically limited, denotes an alkyl group (e.g. a C1-4alkyl group) which is substituted by two aryl residues (e.g. monocyclic aryl), for example diphenylmethyl-. The term "halogen" or "halo" comprises fluorine (F), chlorine (CI) and bromine (Br). The term "amino" refers to a group having amine functionality for example primary amine (-NH2), secondary amine (e.g. -NHalkyl, for example -NHMe) or tertiary amine (e.g. -N(alkyl)2, for example -NMe2, -NEt2). Stereoisomers: All possible stereoisomers of the claimed compounds are included in the present invention. Where the compounds according to this invention have at least one chiral center, they may accordingly exist as enantiomers. Where the compounds possess two or more chiral centers, they may additionally exist as diastereomers. It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the present invention. Preparation and isolation of stereoisomers: Where the processes for the preparation of the compounds according to the invention give rise to a mixture of stereoisomers, these isomers may be separated by conventional techniques such as preparative chromatography. The compounds may be prepared in racemic form, or individual enantiomers may be prepared either by enantiospecific synthesis or by resolution. The compounds may, for example, be resolved into their components enantiomers by standard techniques, such as the formation of diastereomeric pairs by salt formation with an optically active acid, such as (-)-di-p-toluoyl-d-tartaric acid and/or (+)-di-p-toluoyl-l-tartaric acid followed by fractional crystallization and regeneration of the free base. The compounds may also be resolved by formation of diastereomeric esters or amides, followed by chromatographic separation and removal of the chiral auxiliary. Alternatively, the compounds may be resolved using a chiral HPLC column. pharmaceutically acceptable salts: In view of the close relationship between the free compounds and the compounds in the form of their salts or solvates, whenever a compound is referred to in this context, a corresponding salt or solvate is also intended, provided such is possible or appropriate under the circumstances. Salts and solvates of the compounds of formula (I) and physiologically functional derivatives thereof which are suitable for use in medicine are those wherein the counter-ion or associated solvent is pharmaceutically acceptable. However, salts and solvates having non- pharmaceutically acceptable counter-ions or associated solvents are within the scope of the present invention, for example, for use as intermediates in the preparation of other compounds and their pharmaceutically acceptable salts and solvates. Suitable salts according to the invention include those formed with both organic and inorganic acids or bases. Pharmaceutically acceptable acid addition salts include those formed from hydrochloric, hydrobromic, sulfuric, nitric, citric, tartaric, phosphoric, lactic, pyruvic, acetic, trifluoroacetic, triphenylacetic, sulfamic, sulfanilic, succinic, oxalic, fumaric, maleic, malic, mandelic, glutamic, aspartic, oxaloacetic, methanesulfonic, ethanesulfonic, arylsulfonic (for example p-toluenesulfonic, benzenesulfonic, naphthalenesulfonic or naphthalenedisulfonic), salicylic, glutaric, gluconic, tricarballylic, cinnamic, substituted cinnamic (for example, phenyl, methyl, methoxy or halo substituted cinnamic, including 4-methyl and 4-methoxycinnamic acid), ascorbic, oleic, naphthoic, hydroxynaphthoic (for example 1- or 3-hydroxy-2-naphthoic), naphthaleneacrylic (for example naphthalene-2-acrylic), benzoic, 4-methoxybenzoic, 2- or 4- hydroxybenzoic, 4-chlorobenzoic, 4-phenylbenzoic, benzeneacrylic (for example 1,4- benzenediacrylic), isethionic acids, perchloric, propionic, glycolic, hydroxyethanesulfonic, pamoic, cyclohexanesulfamic, salicylic, saccharinic and trifluoroacetic acid. Pharmaceutically acceptable base salts include ammonium salts, alkali metal salts such as those of sodium and potassium, alkaline earth metal salts such as those of calcium and magnesium and salts with organic bases such as dicyclohexylamine and N-methyl-D-glucamine. All pharmaceutically acceptable acid addition salt forms of the compounds of the present invention are intended to be embraced by the scope of this invention. Polymorph crystal forms: Furthermore, some of the crystalline forms of the compounds may exist as polymorphs and as such are intended to be included in the present invention. In addition, some of the compounds may form solvates with water (i.e. hydrates) or common organic solvents, and such solvates are also intended to be encompassed within the scope of this invention. The compounds, including their salts, can also be obtained in the form of their hydrates, or include other solvents used for their crystallization. Prodrugs: The present invention further includes within its scope prodrugs of the compounds of this invention. In general, such prodrugs will be functional derivatives of the compounds which are readily convertible in vivo into the desired therapeutically active compound. Thus, in these cases, the methods of treatment of the present invention, the term "administering" shall encompass the treatment of the various disorders described with prodrug versions of one or more of the claimed compounds, but which converts to the above specified compound in vivo after administration to the subject. Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in "Design of Prodrugs", ed. H. Bundgaard, Elsevier, 1985. Protective Groups: During any of the processes for preparation of the compounds of the present invention, it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J.F.W. McOmie, Plenum Press, 1973; and T.W. Greene & P.G.M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 1991, fully incorporated herein by reference. The protecting groups may be removed at a convenient subsequent stage using methods known from the art. As used herein, the term "composition" is intended to encompass a product comprising the claimed compounds in the therapeutically effective amounts, as well as any product which results, directly or indirectly, from combinations of the claimed compounds. Carriers and Additives for galenic formulations: Thus, for liquid oral preparations, such as for example, suspensions, elixirs and solutions, suitable carriers and additives may advantageously include water, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents and the like; for solid oral preparations such as, for example, powders, capsules, gelcaps and tablets, suitable carriers and additives include starches, sugars, diluents, granulating agents, lubricants, binders, disintegrating agents and the like. Carriers, which can be added to the mixture, include necessary and inert pharmaceutical excipients, including, but not limited to, suitable binders, suspending agents, lubricants, flavorants, sweeteners, preservatives, coatings, disintegrating agents, dyes and coloring agents. Soluble polymers as targetable drug carriers can include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamidephenol, polyhydroxyethylaspartamide-phenol, or polyethyleneoxidepolyllysine substituted with palmitoyl residue. Furthermore, the compounds of the present invention may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polyactic acid, polyepsilon caprolactone, polyhydroxy butyeric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross- linked or amphipathic block copolymers of hydrogels. Suitable binders include, without limitation, starch, gelatin, natural sugars such as glucose or betalactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like. Summary of the invention According to the invention there are provided compounds of formula (I), including pharmaceutically acceptable salts thereof, including all stereoisomers and polymorphs, wherein: R1 represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl; R2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, -C(O)O- alkyl and -C(O)OH; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)O- alkyl and -C(O)OH; alkenyl; alkynyl; -alkyl-aryl; -alkyl- heteroaryl; -alkyl-heterocyclyl; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -heteroaryl- heteroaryl; -aryl-aryl; -aryl (monocyclic or bicyclic); heteroaryl (monocyclic or bicyclic); heterocyclyl; or R2 together with R4 may form a carbocyclyl group optionally substituted by one or more alkyl groups; R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O- alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O- alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo ; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -aryl-O-aryl; - heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl- C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH-alkyl-heterocyclyl; -alkyl- C(O)-(N-piperidinyl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. R4 represents H or alkyl. The compounds of the present invention act as inhibitors of glutaminyl cyclase (QC, EC 2.3.2.5) and QC-like enzymes. Detailed description of the invention According to the invention there are provided compounds of formula (I), including pharmaceutically acceptable salts thereof, including all stereoisomers and polymorphs, wherein: R1 represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl; R2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, -C(O)O-alkyl and -C(O)OH; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)O-alkyl and -C(O)OH; alkenyl; alkynyl; -alkyl-aryl; -alkyl- heteroaryl; -alkyl-heterocyclyl; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -heteroaryl- heteroaryl; -aryl-aryl; -aryl (monocyclic or bicyclic); heteroaryl (monocyclic or bicyclic); heterocyclyl; or R2 together with R4 may form a carbocyclyl group optionally substituted by one or more alkyl groups; R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O-alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo ; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -aryl-O-aryl; - heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl- C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH-alkyl-heterocydyl; -alkyl- C(OMN-piperidinyl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. R4 represents H or alkyl. which is disclosed by CAS under Reference 296898-35-6; and Ph which is disclosed by CAS under Reference 499974-67-3. When R1 represents heteroaryl, examples include monocyclic (e.g. 5 and 6 membered) and bicyclic (e.g. 9 and 10 membered, particularly 9 membered) heteroaryl rings, especially rings containing nitrogen atoms (e.g. 1 or 2 nitrogen atoms). A suitable bicyclic heteroaryl ring is a 9- membered heteroaryl ring containing 1 or 2 nitrogen atoms, especially a benzene ring fused to a 5-membered ring containing one or two nitrogen atoms (e.g. 1 H-benzoimidazolyl). Most suitably the point of attachment is through a benzene ring, e.g. the group is 1H-benzoimidazol- 5-yl. Aforementioned heteroaryl groups may either be unsubstituted (which is more typical) or may suitably be substituted by one or more (e.g. 1 or 2) substituents selected from alkyl (e.g. C1-4alkyl), alkoxy- (e.g. C1-4alkoxy-) and halogen (e.g. F). When R1 represents -carbocyclyl-heteroaryl, examples of carbocycyl include cycloalkyl (e.g. cyclohexyl) and cycloalkenyl (e.g. cyclohexenyl), examples of heteroaryl groups include monocyclic (e.g. 5 or 6 membered, particularly 5 membered) rings especially rings containing nitrogen atoms e.g. 1 or 2 nitrogen atoms. Aforementioned heteroaryl groups may either be unsubstituted (which is more typical) or may suitably be substituted by one or more (e.g. 1 or 2) substituents selected from alkyl (e.g. C1-4 alkyl), alkoxy- (e.g. C1-4 alkoxy-) and halogen (e.g. F). A suitable heteroaryl group is imidazol-1-yl. An exemplary -carbocyclyl-heteroaryl group is 3- imidazol-1 -yl-cyclohexyl-. When R1 represents -alkenylheteroaryl, examples of alkenyl include C2-6 alkenyl, especially C2-4 alkenyl, in particular propenyl and examples of heteroaryl groups include monocyclic (e.g. 5 or 6 membered, particularly 5 membered) rings especially rings containing nitrogen atoms e.g. 1 or 2 nitrogen atoms. Aforementioned heteroaryl groups may either be unsubstituted (which is more typical) or may suitably be substituted by one or more (e.g. 1 or 2) substituents selected from alkyl (e.g. C1-4alkyl), alkoxy- (e.g. C1-4 alkoxy-) and halogen (e.g. F). A suitable heteroaryl group is imidazolyl, particularly imidazol-1-yl. An exemplary -alkenylheteroaryl group is 3-imidazol-1- yl-prop-2-enyl-. When R1 represents -alkylheteroaryl, examples of alkyl include C1-6 alkyl, especially C2-4 alkyl, in particular propyl, and examples of heteroaryl groups include monocyclic (e.g. 5 or 6 membered, particularly 5 membered) rings especially rings containing nitrogen atoms e.g. 1 or 2 nitrogen atoms. Aforementioned heteroaryl groups may either be unsubstituted (which is most typical) or may suitably be substituted by one or more (e.g. 1 or 2) substituents selected from alkyl (e.g. C1-4 alkyl), alkoxy- (e.g. C1-4 alkoxy-) and halogen (e.g. F). A suitable heteroaryl group is imidazol-1-yl. A particularly suitable -alkylheteroaryl group is 3-imidazol-1-yl-propyl-. Particular examples of R1 heteroaryl groups include a 5-membered ring containing 2 or 3 nitrogen atoms, which ring may optionally be substituted (e.g. in particular by one or two groups, such as methyl or-C(NH)NH2), for example: Other examples of R1 heteroaryl groups include a 9-membered bicyclic ring containing 2 nitrogen atoms, which ring may optionally be substituted, for example: Clearly, the heteroaryl groups shown above may also be present as part of a larger R1 function such as -carbocyclyl-heteroaryl, -alkenylheteroaryl or-alkylheteroaryl. When R2 represents alkyl (e.g. C1-8alkyl), examples include methyl, ethyl, propyl, butyl (e.g. n- butyl, sec-butyl, iso-butyl, tert-butyl), pentyl (e.g. n-pentyl) hexyl (e.g. n-hexyl) (i.e. C1-6alkyl), or heptyl (e.g. n-heptyl). When R2 represents -alkyl-amino (e.g. C1-6alkyl-amino), examples include dimethylamino- methyl-, 1-dimethylamino-ethyl-, 2-dimethylamino-ethyl-, 1-dimethyiamino-propyl-, 2- dimethylamino-propyl-, 3-dimethylamino-propyl-, diethylamino-methyl-, 1-diethylamino-ethyl-, 2- diethylamino-ethyl-, 1-diethylamino-propyl-, 2-diethylamino-propyl- and 3-diethylamino-propyl-. When R2 represents -alkyl-thioalkyl (e.g. C1-4alkyl-C1-4thioalkyl), examples include -CH2SMe, -CH2CH2SMe and -CH2SEt. When R2 represents haloalkyl- (e.g. -C1-6haloalkyl), examples include CF3. When R2 represents hydroxyalkyl- (e.g. -C1-6hydroxyalkyl), examples include-CH2OH. When R2 represents -alkyl-alkoxyl (e.g. -C1-4alkyl-C1-4-alkoxy), examples include -CH2OMe. When R2 represents-alkyl-COOH (e.g. C1-6alkyl-COOH), examples include -CH2COOH. When R2 represents -alkyl-C(O)O-alkyl (e.g. C1-4alkyl-C(O)O-C1-4alkyl), examples include -CH2C(O)OMe, -CH2C(O)OEt, -CH2C(O)OtBu, -CH2CH2C(O)OMe, -CH2CH2C(O)OEt and -CH2CH2C(O)OtBu. When R2 represents carbocyclyl, examples include cycloalkenyl (e.g. cyclohex-2-enyl, cyclohex- 3-enyl, and cycloalkyl (e.g. cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl). When R2 represents substituted carbocyclyl, examples include (S)-2-methyl-cyclohex-2-enyl, cyclopropanecarboxylic acid ethyl ester, trifluoromethyl-cyclohexyl-, fluoro-cyclohexyl-, methoxy- cyclohexyl- and 3-methyl-cyclohexyl, aminocyclohexyl, thiomethyl-cyclohexyl-, hydroxycyclohexyl-. When R2 represents alkenyl (e.g. C2-6alkenyl), examples include vinyl (i.e. ethyenyl), propenyl (e.g. propen-1-yl, propen-2-yl), butenyl, pentenyl and (1E, 3E)-pentadienyl. When R2 represents alkynyl (e.g. C2-6alkynyl), examples include ethynyl. When R2 represents -alkyl-aryl (e.g. C1-4alkyl-aryl), examples include benzyl (i.e. phenyl- methyl-), phenyl-ethyl- (e.g. 1-phenyl-ethyl-, 2-phenyl-ethyl-), phenyl-propyl- (e.g. 1-phenyl- propyl-, 2-phenyl-propyl-, 3-phenyl-propyl-), tolyl-methyl-, tolyl-ethyl- (e.g. 1-tolyl-ethyl-, 2-tolyl- ethyl-), tolyl-propyl- (e.g. 1-tolyl-propyl-, 2-tolyl-propyl-, 3-tolyl-propyl-). When R2 represents -alkyl-heteroaryl (e.g. C1-4alkyl-heteroaryl), examples include -propyl-3- benzo[1,3]dioxol-5-yl, (5-methyl-furan-2-yl)-methyl-, (5-methyl-furan-2-yl)-ethyl-, (5-methyl- furan-2-yl)-propyl-, (5-methyl-furan-3-yl)-methyl-, (5-methyl-furan-3-yl)-ethyl-, (5-methyl-furan-3- yl)-propyl-, (5-methyl-pyrrol-2-yl)-methyl-, (5-methyl-pyrrol-2-yl)-ethyl-, (5-methyl-pyrrol-2-yl)- propyl-, (5-methyl-pyrrol-3-yl)-methyl-, (5-methyl-pyrrol-3-yl)-ethyl-, (5-methyl-pyrrol-3-yl)- propyl-, (5-methyl-thiophen-2-yl)-methyl-, (5-methyl-thiophen-2-yl)-ethyl-, (5-methyl-thiophen-2- yl)-propyl-, (5-methyl-thiophen-3-yl)-methyl-, (5-methyl-thiophen-3-yl)-ethyl-, (5-methyl- thiophen-3-yl)-propyk When R2 represents -aryl heteroaryl (such as -(monocyclic aryl)-(monocyclic heteroaryl)), examples include 4-(pyridin-2-yl)-phenyl-, 4-(pyridin-3-yl)-phenyl-, 4-(pyridin-4-yl)-phenyl- When R2 represents —aryl-aryl (such as -(monocyclic aryl)-(monocyclic aryl)), examples include -biphenyl. When R2 represents -heteroaryl-heteroaryl (such as -(monocyclic heteroaryl)-(monocyclic heteroaryl)), examples include 4-(pyridin-2-yl)-pyridin-2-yl-. When R2 represents -heteroaryl-aryl (such as -(monocyclic heteroaryl)-(monocyclic aryl)), examples include (4-phenyl)-pyridin-2-yl-. When R2 represents -alkylcarbocyclyl (e.g. C1-4alkyl-carbocyclyl), examples include -methylcycloalkyl e.g. -methyl-cyclohexyl. When R2 represents -alkylheterocyclyl (e.g. C1-4alkyl-heteroyclyl), examples include -methyl- piperidin-1-yl. When R2 represents -aryl, R2 can be monocyclic or bicyclic but suitably monocyclic. R2 may be unsubstituted (e.g. phenyl or naphthyl) or substituted. Examples of substituted R2 include o- tolyl, m-tolyl, p-tolyl, 2,4-dimethyl-phenyl-, 3,4-dimethyl-phenyl-, 3,5-dimethyl-phenyl-, 2,4,5- trimethyl-phenyl-, 2-methoxy-phenyl-, 3-methoxy-phenyl-, 4-methoxy-phenyl-, 2-fluoro-phenyl-, 3-fluoro-phenyl-, 4-fluoro-phenyl-, 3,4-difluoro-phenyl-, 3,5-difluoro-phenyl-, 2-chloro-phenyl-, 3- chloro-phenyl-, 4-chloro-phenyl-, 3,4-dichloro-phenyl-, 3,5-dichloro-phenyl-, 2-bromo-phenyl-, 3- bromo-phenyl-, 4-bromo-phenyl-, 3,4-dibromo-phenyl-, 3,5-dibromo-phenyl-, 2-hydroxy-phenyl-, 3-hydroxy-phenyl-, 4-hydroxy-phenyl-, 2-hydroxy-5-chloro-phenyl-, 2-hydroxy-5-methyl-phenyl-, 2-methyl-4-methoxy-phenyl-, 3-benzoic acid methyl ester-, 3-bromo-4-methoxy-phenyl-, 3- cyano-4-fluoro-phenyl-, 3-fluoro-4-methoxy-phenyl-, 3-hydroxy-4-methoxy-phenyl-, 3-propoxy- phenyl-, 4-chloro-3-fluoro-phenyl-, 4-chloro-3-nitro-phenyl-, 4-dimethylamino-phenyl-, 4-ethyl- phenyl-, 4-methoxy-2,5-dimethyl-phenyl-, 4-methoxy-2-methyl-phenyl-, 4-methoxy-2-hydroxy- phenyl-, 4-methanesulfanyl-phenyl-, 5-chloro-2-hydroxy-phenyl-. When R2 represents heteroaryl, examples include monocyclic and bicyclic ring systems, which may be unsubstituted or substituted. When R2 is unsubstituted bicyclic heteroaryl, examples include 1 H-indol-3-yl, 1 H-indol-5-yl, benzo[c][1,2,5]thiadiazol-5-yl, benzo[b]thiophen-3-yl, benzofuran-2-yl, quinolin-2-yl, quinolin-3-yl and quinolin-4-yl. When R2 is unsubstituted monocyclic heteroaryl, examples include thiophen-2-yl, thiophen-3-yl, furan-2-yl, pyridin-2-yl, pyridin-3-yl and pyridin-4-yl. When R2 is substituted bicyclic heteroaryl, examples include 8- hydroxy-quinolin-2-yl, 6-fluoro-1H-indol-3-yl, 6-methyl-1H-indol-3-yl, chromen-2-one, chromen- 4-one, 6-methyl-chromen-4-one and benzo[1,3]dioxol-5-yl. When R2 is substituted monocyclic heteroaryl, examples include 5-methyl-thiophen-2-yl, 5-ethyl-thiophen-2-yl, 5-methyl-furan-2-yl, 5-ethyl-furan-2-yl, 2,4-dimethoxy-pyrimidin-5-yl and 5-methylhydroxy-furan-2-yl. When R2 represents heterocyclyl, examples include (S)-3,4-dihydro-2H-pyran-2-yl. When R2 and R4 together form a carbocyclyl group, R2 and R4 may for example together form a cycloalkyl group. For example R2 and R4 may together form a -(CH2)2-8- alkylene chain, suitably -(CH2)2-5-. Specific examples include -(CH2)3- (i.e. spiro-cyclobutyl), -(CH2)4- (i.e. spiro- cyclopentyl) and -(CH2)5- (i.e. spiro-cyclohexyl). Alternatively (and less suitably) R2 and R4 may for example together form a cycloalkenyl group. The carbocyclyl group represented by R2 and R4 together may not be substituted or may be substituted by e.g. 1 or 2 alkyl groups such as methyl groups. Suitably it is not substituted. In one embodiment, R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O-alkyl; alkenyl; - alkyl-aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl- heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo ; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl- aryl; -heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; - alkyl-C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH-alkyl-heterocyclyl; - alkyl-C(O)-(N-piperidinyl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. When R3 represents alkyl (e.g. C1-6alkyl), examples include methyl, ethyl, propyl, butyl (e.g. n- butyl, iso-butyl, sec-butyl, tert-butyl), 2,2-dimethyl-propyl, pentyl (e.g. n-pentyl), hexyl (e.g. n- hexyl). When R3 represents alkoxy-alkyl- (e.g. C1-4alkoxy-C1-4alkyl-), examples include methoxy- methyl-, 1-methoxy-ethyl-, 2-methoxy-ethyl-, 1-methoxy-propyl-, 2-methoxy-propyl-, 3-methoxy- propyl-, ethoxy-methyl-, 1-ethoxy-ethyl-, 2-ethoxy-ethyl-, 1-ethoxy-propyl-, 2-ethoxy-propyl- and 3-ethoxy-propyl-. When R3 represents -alkyl-C(O)Oalkyl (e.g. -C1-4alkyl-C(O)O-C1-4alkyl), examples include -CH2C(O)OMe, -CH2C(O)OEt, -CH2C(O)OPr, -CH2C(O)OtBu. When R3 represents -alkyl-amino (e.g. -C1-4alkylamino), examples include dimethylamino- methyl-, 1-dimethylamino-ethyl-, 2-dimethylamino-ethyl-, 1-dimethylamino-propyl-, 2- dimethylamino-propyl-, 3-dimethylamino-propyl-, diethylamino-methyl-, 1-diethylamino-ethyl-, 2- diethylamino-ethyl-, 1-diethylamino-propyl-, 2-diethylamino-propyl-, 3-diethylamino-propyk When R3 represents haloalkyl (e.g. -C1-6haloalkyl), examples include CF3. When R3 represents hydroxyalkyl (e.g. -C1-6hydroxyalkyl), examples include -CH2OH. When R3 represents -alkyl-thioalkyl (e.g. -C1-4alkyl-C1-4-thioalkyl), examples include -CH2SMe. When R3 represents -alkyl-COOH (e.g. C1-6alkyl-COOH), examples include -CH2COOH. When R3 represents carbocyclyl, it may optionally be substituted. Examples of unsubstituted carbocyclyl include cycloalkenyl (e.g. cyclohex-1-enyl, cyclohex-3-enyl) and cycloalkyl (e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl). Thus cycloalkyl may represent cyclopropyl, cyclobutyl, cyclopentyl or cycloheptyl. Alternatively it may represent cyclohexyl. Examples of substituted carbocyclyl include cycloalkyl or cycloalkenyl substituted by alkyl (e.g. 2-methyl-cyclohexyl), halogen (e.g. 1, 2 or 3 halogen atoms such as chlorocyclohexyl); -haloalkyl (e.g. CF3), hydroxyl (e.g. hydroxycyclohexyl- and 3,4-dihydroxy-cyclohexyl-); -C(O)O- - alkyl (e.g. cyclohexyl substituted by -C(O)OMe or -C(O)OEt); -C(O)OH (e.g. cyclohexyl substituted by -C(O)OH); alkoxy, (e.g. cyclohexyl substituted by methoxy, cyclohexenyl substituted by methoxy-); -thioalkyl (e.g. cyclohexyl substituted by -thioalkyl); amino (e.g. cyclohexyl substituted by amino). Examples of -cycloalkyl-C(O)Oalkyl (e.g. -cycloalkyl-C(O)O- -C1-4alkyl) include -cyclopentane-2- carboxylic acid ethyl ester, -cyclopentane-2-carboxylic acid ethyl ester-3-methyl, -cyclohexane- 2-carboxylic acid ethyl ester, -cyclopentane-2-(carboxylic acid methyl ester), -cyclopentane-2- carboxylic acid methyl ester, -3-methyl, -cyclohexane-2-carboxylic acid methyl ester. When R3 represents alkenyl (e.g. C2-6alkenyl), examples include vinyl (i.e. ethenyl), propenyl (e.g. propen-1-yl, propen-2-yl (i.e. allyl)), (1E, 3E)-butadienyl, (1E, 3E)-pentadienyl. When R3 represents -alkyl aryl (e.g. -C1-4alkyl aryl), examples include benzyl, 1-phenyl-ethyl-, 2- phenyl-ethyl-, 1-tolyl-ethyl-, 2-tolyl-ethyl-, 3-phenyl-propyl-, 3-tolyl-propyl-, 4-phenyl-butyl-, 4- tolyl-butyl-, 2-chloro-benzyl-, 3-chloro-benzyl- and 4-chloro-benzyl-. In one embodiment, examples include 1-phenyl-ethyl-, 2-phenyl-ethyl-, 1-tolyl-ethyl-, 2-tolyl-ethyl-, 3-phenyl-propyl-, 3-tolyl-propyl-, 4-phenyl-butyl-, 4-tolyl-butyl-, 2-chloro-benzyl-, 3-chloro-benzyl- and 4-chloro- benzyl-. Further examples include (2-fluorophenyl)-methyl-, β-fluorophenyl)-methyl-, (4- fluorophenyl)-methyl- and (2,4-difluorophenyl)-methyl-. When R3 represents -alkyl(aryl)2 (e.g. -C1-4alkyl(aryl)2), examples include diphenylmethyl-, 1,2- diphenyl-ethyl-, 2,2-diphenyl-ethyl-, 3,3-diphenyl-propyl-, ditolylmethyl-, 2,2-ditolyl-ethyl-, and 3,3-ditolyl-propyl-. When R3 represents -alkyl(heteroaryl)2 (e.g. -C1-4alkyl (heteroaryl)2), examples include 2,2- pyridinyl-methyl-, 2,2-pyridinyl-ethyl- and 3,3-pyridinyl-propyl-. When R3 represents -alkyl(aryl)(heteroaryl) (e.g. -C1-4alkyl (aryl)(heteroaryl)) examples include 2-phenyl-2-pyridinyl-methyl-, 2-phenyl-2-pyridinyl-ethyl- and 3-phenyl-3-pyridinyl-propyk When R3 represents -alkyl-heteroaryl (e.g. -C1-4alkyl-heteroaryl), examples include pyridin-2-yl- methyl-, pyridin-3-yl-methyl-, pyridin-4-yl-methyl-, 2-thiophen-2-yl-ethyl-, furan-2-yl-methyl- and pyrrolyl-methyl-. In one embodiment examples include pyridin-2-yl-methyl-, pyridin-4-yl-methyl-, 2-thiophen-2-yl-ethyl-, furan-2-yl-methyl- and pyrrolyl-methyl-. When R3 represents -alkyl heterocyclyl (e.g. -C1-4alkyl heterocyclyl) which heterocycyl group may optionally be substituted by one or more groups selected from alkyl, hydroxyl and oxo, examples include 2,2-dimethyl-[1,3]dioxolan-4-ylmethyl-, (tetrahydro-furan-2-yl)methyl- and - propyl-3-pyrrolidin-2-one. Suitably heterocyclyl is not substituted. When R3 represents -alkylcarbocyclyl (e.g. C1-4alkyl-carbocyclyl), examples include - methylcycloalkyl e.g. -methyl-cyclohexyl. When R3 represents -aryl-heteroaryl (such as -(monocyclic aryl)-(monocyclic heteroaryl)), examples include 4-pyridin-2-yl-phenyl-. When R3 represents -aryl-aryl (such as -(monocyclic aryl)-(monocyclic aryl)), examples include -biphenyl. When R3 represents-aryl-O-aryl examples include phenoxyphenyl (e.g. 4-phenoxyphenyl). When R3 represents -heteroaryl-heteroaryl (such as -(monocyclic heteroaryl)-(monocyclic heteroaryl)), examples include 4-(pyridin-2-yl)-pyridin-2-yl-. When R3 represents -heteroaryl-aryl (such as -(monocyclic heteroaryl)-(monocyclic aryl)), examples include (4-phenyl)-pyridin-2-yk When R3 represents aryl, examples include phenyl optionally substituted by one or more substituents e.g. one or more substituents selected from nitro, alkyl (e.g. tert-butyl), alkoxy, halogen and haloalkyl; e.g. one substituent, e.g. one substituent at the 4-position. Thus when R3 represents aryl, examples include 4-nitro-phenyl- and 4-tert-butyl-phenyl-. When R3 represents heteroaryl, examples include 2,3-dihydro-benzo[1,4]dioxin-6-yl. Another example is benzo-1,3-dioxol-5-yl. Further examples include furanyl, pyrrolyl and thiophenyl. When R3 represents heterocyclyl, examples include tetrahydrofuran-2-yl, 3,4-dihydro-2H- pyranyl, piperidinyl and pyrrolidinyl. When R3 represents -aryl-alkyl-aryl (e.g. -aryl-C1-4alkyl-aryl, especially wherein aryl represents monocyclic aryl), examples include 4-benzyl-phenyl- and 4-(4-methyl-benzyl)-phenyl- When R3 represents -aryl-Oalkyl-aryl (e.g. -aryl-O-C1-4alkyl-aryl, especially wherein aryl represents monocyclic aryl), examples include 2-benzyloxy-phenyl-. When R3 represents -alkyl-C(O) -NH-alkyl-aryl (e.g. -C1-4alkyl-C(O)-NH-C1-4alkyl-aryl), examples include -CH2-C(O) -N-alkyl-aryl, (e.g. -CH2-C(O) -N-CH2-phenyl). When R3 represents -alkyl-C(O) -NH-alkyl-heteroaryl (e.g. -C1-4alkyl-C(O) -NH-C1-4 alkyl- heteroaryl), examples include -methyl-CONH-ethyl-heteroaryl e.g. CH2C(O) N-CH2CH2-(1H- indol-3-yl). When R3 represents alkyl-C(O) -(N-piperidinyl) or -alkyl-C(O) -(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl, examples include -methyl-C(O) -(N-piperidinyl) or -methyl-C(O) -(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused (e.g. between the 3 and 4 position) to phenyl. When R3 represents -alkyl-C(O) -NH-alkyl-heterocyclyl (e.g. -C1-4alkyl-C(O) -NH-C1-4 alkyl- heterocyclyl), examples include-CH2CONHCH2(piperidin-1-yl). When R4 represents alkyl (e.g. C1-4alkyl), examples include methyl, ethyl and propyl. Suitably, R1 represents represents heteroaryl or-alkylheteroaryl, particularly-alkylheteroaryl. Suitably, when R1 represents heteroaryl, R1 represents bicyclic heteroaryl, especially 9- membered bicyclic heteroaryl. More suitably, R1 represents a bicyclic heteroaryl ring system and in particular a phenyl ring fused with a 5 membered heteroaryl ring containing one or more (e.g. one or two, suitably one) nitrogen atoms. Suitably R1 represents unsubstituted heteroaryl. In particular, R1 suitably represents 1H-benzoimidazolyl, especially 1H-benzoimidazol-5-yl. Suitably, when R1 represents -alkylheteroaryl, alkyl represents C2-4 alkyl, e.g. C3-4 alkyl most suitably propyl. When R1 represents -alkylheteroaryl, R1 heteroaryl is suitably 5 or 6 membered monocyclic heteroaryl, especially 5 membered monocyclic heteroaryl. Suitably, when R1 represents -alkylheteroaryl, the heteroaryl ring contains nitrogen atoms (e.g. 1 or 2 nitrogen atoms, suitably 2 nitrogen atoms) and is suitably unsubstituted. A particularly suitable heteroaryl group is imidazolyl, especially imidazol-1-yl. Most suitably, when R1 represents - alkylheteroaryl, R1 represents 3-imidazoL-1-yl-propyl-. Suitably, R2 represents alkyl, which may optionally be substituted by one or more groups selected from -thioalkyl and -C(O)0-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from -alkyl, -thioalkyl and -C(O)0-alkyl; alkenyl; -alkyl-aryl; -alkyl- heteroaryl; -aryl heteroaryl; -aryl (e.g. optionally substituted phenyl); heteroaryl (monocyclic or bicyclic); heterocyclyl; or R2 together with R4 represents carbocyclyl optionally substituted by one or more (e.g. 1 or 2) methyl groups. More suitably, R2 represents -aryl-heteroaryl, aryl or heteroaryl; or R2 together with R4 represents cycloalkyl (e.g. cyclobutyl). Most suitably, R2 represents -aryl or heteroaryl; or R2 together with R4 represents cycloalkyl (e.g. cyclobutyl). Particularly suitably R2 represents aryl or heteroaryl, especially aryl. When R2 represents -aryl-heteroaryl, R2 is suitably 4-pyridin-2-yl-phenyl-. When R2 represents aryl, R2 is suitably monocyclic, especially substituted phenyl. Most suitably, R2 represents: 2-hydroxy-5-methyl-phenyl-, 2-methyl-4-methoxy-phenyl-, 3,4-dichloro- phenyl-, 3,5-dibromo-phenyl-, 2-benzoic acid methyl ester, 3-bromo-4-methoxy-phenyl-, 3- hydroxy-4-methoxy-phenyl-, 3-propoxy-phenyl-, 4-bromo-phenyl-, 4-chloro-3-nitro-phenyl-, 4- methoxy-2-methyl-phenyl-, 4-methoxy-phenyl. When R2 represents heteroaryl, R2 is suitably bicyclic. Most suitably, R2 represents 1H-indol-5- yl, 2-quinolin-8-ol, benzo[1,2,5]thiophen-3-yl, benzo[b]thiophen-3-yl, benzofuran-2-yl, quinolin-2- yl, quinolin-3-yl, benzo[1,3]dioxol-5-yl. Suitably R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)0-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)0-alkyl; alkenyl; - alkyl-aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl- heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo ; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl- aryl; -heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; - alkyl-C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH-alkyl-heterocyclyl; - alkyl-C(O)-(N-piperid'myl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. More suitably, R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, alkoxy-, and -C(O)0-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, alkoxy-, and -C(O)0-alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl)2, -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more (e.g. 1 or 2) groups selected from alkyl (e.g. methyl) and oxo; -aryl; heteroaryl (monocyclic or bicyclic); -aryl-Oalkyl-aryl; -alkyl-C(O)-NH- alkyl-heteroaryl; -alkyl-C(O)NH-(N-piperidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. More suitably, R3 represents alkyl or cycloalkyl either of which can be unsubstituted or substituted by -C(O)Oalkyl; alkyl substituted by alkoxy; -aryl- Oalkyl-aryl; -alkyl-aryl; -alkyl-heteroaryl; -alkyl-heterocyclyl; -alkyl-C(O)-NH-alkyl-heteroaryl. Yet more suitably, R3 represents unsubstituted alkyl, alkyl substituted by -C(O)Oalkyl; -alkyl-aryl; or -alkyl-heteroaryl, especially unsubstituted alkyl (e.g. C1-6alkyl). When R3 represents a moiety comprising an aryl group, aryl is suitably substituted aryl (such as substituted phenyl). Suitably, when R3 represents unsubstituted alkyl, R3 represents n-butyl, t-butyl or 2,2-dimethyl- propyl, particularly 2,2-dimethylpropyl. Suitably, when R3 represents unsubstituted cycloalkyl, R3 represents cyclopentyl or cyclohexyl. Suitably, when R3 represents -alkyl-C(O)Oalkyl, R3 represents -CH2C(O)OMe or -CH2C(O)OtBu. Suitably, when R3 represents -cycloalkyl-C(O)Oalkyl, R3 represents cyclohexane-2-carboxylic acid ethyl ester. Suitably, when R3 represents alkoxy-alkyl-, R3 represents 3-methoxy-propyl-. Suitably, when R3 represents -aryl-Oalkyl-aryl, R3 represents 2-benzyloxy-phenyl-. Suitably, when R3 represents -alkyl-aryl, aryl represents phenyl or substituted phenyl, e.g. phenyl substituted by one or more halogen atoms. For example, R3 may represent benzyl, 2- chloro-benzyl- or 4-chloro-benzyl. Suitably, when R3 represents -alkyl-heteroaryl, R3 represents pyridin-3-yl-methyl- or 2-thiophen- 2-yl-ethyl-. Suitably, when R3 represents -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxyl and oxo, R3 represents 1- (tetrahydro-furan-2-yl)methyl- e.g. (S)-1 -(tetrahydro-furan-2-yl)methyl-. Suitably, when R3 represents -alkyl-C(O)-N-alkyl-aryl, R3 represents -CH2C(O)N-(2-(1 H-indol-3- yl)-ethyl). When R2 together with R4 does not form a carbocyclyl group, suitably R4 represents hydrogen. Processes A process for preparation of compounds of formula (I) or a protected derivative thereof comprises reaction of a compound of formula (II) or a protected derivative thereof, wherein R1 and R2 are as defined above, with a suitable azide such as trimethylsilylazide and a compound of formula (III) or a protected derivative thereof, wherein R3 is as defined above. The reagents will typically be combined in a polar protic organic solvent (e.g. an alcohol such as methanol). Compounds of formula (III) are either known or may be prepared by conventional methods known per se. Compounds of formula (II) or a protected derivative thereof may be prepared by reaction of a compound of formula (IV), R1 NH2 (IV) or a protected derivative thereof, wherein R2 is as defined above, with a compound of formula (V) or a protected derivative thereof, wherein R1 is as defined above under suitable imine-forming reaction conditions. Suitable conditions include combining the reagents in a polar protic solvent at ambient or elevated temperature. In a suitable method of preparing compounds of formula (I), compounds of formula (II) are prepared in situ and are not isolated before further reaction with (III). Therapeutic uses Physiological substrates of QC (EC) in mammals are, e.g. amyloid beta-peptides β-40), β-42), (11-40 and (11-42), ABri, ADan, Gastrin, Neurotensin, FPP, CCL 2, CCL 7, CCL 8, CCL 16, CCL 18, Fractalkine, Orexin A, [Gln3]-glucagonβ-29), [Gln5]-substance P(5-11) and the peptide QYNAD. For further details see table 1. The compounds and/or combinations according to the present invention and pharmaceutical compositions comprising at least one inhibitor of QC (EC) are useful for the treatment of conditions that can be treated by modulation of QC activity. Table 1: Amino acid sequences of physiological active peptides with an N-terminal glutamine residue, which are prone to be cyclized to final pGlu Glutamate is found in positions 3, 11 and 22 of the amyloid β-peptide. Among them the mutation from glutamic acid (E) to glutamine (Q) in position 22 (corresponding to amyloid precursor protein APP 693, Swissprot P05067) has been described as the so called Dutch type cerebroarterial amyloidosis mutation. The p-amyloid peptides with a pyroglutamic acid residue in position 3, 11 and/or 22 have been described to be more cytotoxic and hydrophobic than the amyloid β-peptides 1-40(42/43) (Saido T.C. 2000 Medical Hypotheses 54β): 427-429). The multiple N-terminal variations, e.g. Abeta(3-40), Abeta β-42), Abeta(11-40) and Abeta (11- 42) can be generated by the β-secretase enzyme β-site amyloid precursor protein-cleaving enzyme (BACE) at different sites (Huse J.T. et al. 2002 J. Biol. Chem. 277 (18): 16278-16284), and/or by aminopeptidase or dipeptidylaminopeptidase processing from the full lenght peptides Abeta(1-40) and Abeta(1-42). In all cases, cyclization of the then N-terminal occuring glutamic acid residue is catalyzed by QC. Transepithelial transducing cells, particularly the gastrin (G) cell, co-ordinate gastric acid secretion with the arrival of food in the stomach. Recent work showed that multiple active products are generated from the gastrin precursor, and that there are multiple control points in gastrin biosynthesis. Biosynthetic precursors and intermediates (progastrin and Gly-gastrins) are putative growth factors; their products, the amidated gastrins, regulate epithelial cell proliferation, the differentiation of acid-producing parietal cells and histamine-secreting enterochromaffin-like (ECL) cells, and the expression of genes associated with histamine synthesis and storage in ECL cells, as well as acutely stimulating acid secretion. Gastrin also stimulates the production of members of the epidermal growth factor (EGF) family, which in turn inhibit parietal cell function but stimulate the growth of surface epithelial cells. Plasma gastrin concentrations are elevated in subjects with Helicobacter pylori, who are known to have increased risk of duodenal ulcer disease and gastric cancer (Dockray, G.J. 1999 J Physiol 15 315-324). The peptide hormone gastrin, released from antral G cells, is known to stimulate the synthesis and release of histamine from ECL cells in the oxyntic mucosa via CCK-2 receptors. The mobilized histamine induces acid secretion by binding to the H(2) receptors located on parietal cells. Recent studies suggest that gastrin, in both its fully amidated and less processed forms (progastrin and glycine-extended gastrin), is also a growth factor for the gastrointestinal tract. It has been established that the major trophic effect of amidated gastrin is for the oxyntic mucosa of stomach, where it causes increased proliferation of gastric stem cells and ECL cells, resulting in increased parietal and ECL cell mass. On the other hand, the major trophic target of the less processed gastrin (e.g.. glycine-extended gastrin) appears to be the colonic mucosa (Koh, T.J. and Chen, D. 2000 Regul Pept 9337-44). Neurotensin (NT) is a neuropeptide implicated in the pathophysiology of schizophrenia that specifically modulates neurotransmitter systems previously demonstrated to be misregulated in this disorder. Clinical studies in which cerebrospinal fluid (CSF) NT concentrations have been measured revealed a subset of schizophrenic patients with decreased CSF NT concentrations that are restored by effective antipsychotic drug treatment. Considerable evidence also exists concordant with the involvement of NT systems in the mechanism of action of antipsychotic drugs. The behavioral and biochemical effects of centrally administered NT remarkably resemble those of systemically administered antipsychotic drugs, and antipsychotic drugs increase NT neurotransmission. This concatenation of findings led to the hypothesis that NT functions as an endogenous antipsychotic. Moreover, typical and atypical antipsychotic drugs differentially alter NT neurotransmission in nigrostriatal and mesolimbic dopamine terminal regions, and these effects are predictive of side effect liability and efficacy, respectively (Binder, E. B. et al. 2001 Biol Psychiatry 50 856-872). Fertilization promoting peptide (FPP), a tripeptide related to thyrotropin releasing hormone (TRH), is found in seminal plasma. Recent evidence obtained in vitro and in vivo showed that FPP plays an important role in regulating sperm fertility. Specifically, FPP initially stimulates nonfertilizing (uncapacitated) spermatozoa to "switch on" and become fertile more quickly, but then arrests capacitation so that spermatozoa do not undergo spontaneous acrosome loss and therefore do not lose fertilizing potential. These responses are mimicked, and indeed augmented, by adenosine, known to regulate the adenylyl cyclase (AC)/cAMP signal transduction pathway. Both FPP and adenosine have been shown to stimulate cAMP production in uncapacitated cells but inhibit it in capacitated cells, with FPP receptors somehow interacting with adenosine receptors and G proteins to achieve regulation of AC. These events affect the tyrosine phosphorylation state of various proteins, some being important in the initial "switching on," others possibly being involved in the acrosome reaction itself. Calcitonin and angiotensin II, also found in seminal plasma, have similar effects in vitro on uncapacitated spermatozoa and can augment responses to FPP. These molecules have similar effects in vivo, affecting fertility by stimulating and then maintaining fertilizing potential. Either reductions in the availability of FPP, adenosine, calcitonin, and angiotensin II or defects in their receptors contribute to male infertility (Fraser, L.R. and Adeoya-Osiguwa, S. A. 2001 Vitam Horm 63, 1- 28). CCL2, CCL7, CCL8, CCL16, CCL18 and fractalkine play an important role in pathophysiological conditions, such as suppression of proliferation of myeloid progenitor cells, neoplasia, inflammatory host responses, cancer, psoriasis, rheumatoid arthritis, atherosclerosis, vasculitis, humoral and cell-mediated immunity responses, leukocyte adhesion and migration processes at the endothelium, inflammatory bowel disease, restenosis, pulmonary fibrosis, pulmonary hypertention, liver fibrosis, liver cirrhosis, nephrosclerosis, ventricular remodeling, heart failure, adenopathy after organ transplantations and failure of vein grafts. Several cytotoxic T lymphocyte peptide-based vaccines against hepatitis B, human immunodeficiency virus and melanoma were recently studied in clinical trials. One interesting melanoma vaccine candidate alone or in combination with other tumor antigens, is the decapeptide ELA. This peptide is a Melan-A/MART-1 antigen immunodominant peptide analog, with an N-terminal glutamic acid. It has been reported that the amino group and gamma- carboxylic group of glutamic acids, as well as the amino group and gamma-carboxamide group of glutamines, condense easily to form pyroglutamic derivatives. To overcome this stability problem, several peptides of pharmaceutical interest have been developed with a pyroglutamic acid instead of N-terminal glutamine or glutamic acid, without loss of pharmacological properties. Unfortunately compared with ELA, the pyroglutamic acid derivative (PyrELA) and also the N-terminal acetyl-capped derivative (AcELA) failed to elicit cytotoxic T lymphocyte (CTL) activity. Despite the apparent minor modifications introduced in PyrELA and AcELA, these two derivatives probably have lower affinity than ELA for the specific class I major histocompatibility complex. Consequently, in order to conserve full activity of ELA, the formation of PyrELA must be avoided (Beck A. et al. 2001, J Pept Res 57(6):528-38.). Orexin A is a neuropeptide that plays a significant role in the regulation of food intake and sleep-wakefulness, possibly by coordinating the complex behavioral and physiologic responses of these complementary homeostatic functions. It plays also a role in the homeostatic regulation of energy metabolism, autonomic function, hormonal balance and the regulation of body fluids. Recently, increased levels of the pentapeptide QYNAD were identified in the cerebrospinal fluid (CSF) of patients suffering from multiple sclerosis or Guillain-Barre syndrome compared to healthy individuals (Brinkmeier H. et al. 2000, Nature Medicine 6, 808-811). There is a big controversy in the literature about the mechanism of action of the pentapeptide Gln-Tyr-Asn- Ala-Asp (QYNAD), especially its efficacy to interact with and block sodium channels resulting in the promotion of axonal dysfunction, which are involved in inflammatory autoimmune diseases of the central nervous system. But recently, it could be demonstrated that not QYNAD, but its cyclized, pyroglutamated form, pEYNAD, is the active form, which blocks sodium channels resulting in the promotion of axonal dysfunction. Sodium channels are expressed at high density in myelinated axons and play an obligatory role in conducting action potentials along axons within the mammalian brain and spinal cord. Therefore, it is speculated that they are involved in several aspects of the pathophysiology of inflammatory autoimmune diseases, especially multiple sclerosis, the Guillain-Barre syndrome and chronic inflammatory demyelinizing polyradiculoneuropathy. Furthermore, QYNAD is a substrate of the enzyme glutaminyl cyclase (QC, EC 2.3.2.5), which is also present in the brain of mammals, especially in human brain. Glutaminyl cyclase catalyzes effectively the formation of pEYNAD from its precursor QYNAD. Accordingly, the present invention provides the use of the compounds of formula (I) for the preperation of a medicament for the prevention or alleviation or treatment of a disease selected from the group consisting of mild cognitive impairment, Alzheimer's disease, Familial British Dementia, Familial Danish Dementia, Down Syndrome, Huntington's disease, Kennedy's disease, ulcer disease, duodenal cancer with or w/o Helicobacter pylori infections, colorectal cancer, Zoliiger-Ellison syndrome, gastric cancer with or without Helicobacter pylori infections, pathogenic psychotic conditions, schizophrenia, infertility, neoplasia, inflammatory host responses, cancer, malign metastasis, melanoma, psoriasis, rheumatoid arthritis, atherosclerosis, impaired humoral and cell-mediated immune responses, leukocyte adhesion and migration processes in the endothelium, impaired food intake, impaired sleep-wakefulness, impaired homeostatic regulation of energy metabolism, impaired autonomic function, impaired hormonal balance or impaired regulation of body fluids, multiple sclerosis, the Guillain-Barre syndrome and chronic inflammatory demyelinizing polyradiculoneuropathy. Furthermore, by administration of a compound according to the present invention to a mammal it can be possible to stimulate the proliferation of myeloid progenitor cells. In addition, the administration of a QC inhibitor according to the present invention can lead to suppression of male fertility. In a preferred embodiment, the present invention provides the use of inhibitors of QC (EC) activity in combination with other agents, especially for the treatment of neuronal diseases, artherosclerosis and multiple sclerosis. The present invention also provides a method of treatment of the aforementioned diseases comprising the administration of a therapeutically active amount of at least one compound of formula (I) to a mammal, preferably a human. Most preferably, said method and corresponding uses are for the treatment of a disease selected from the group consisting of mild cognitive impairment, Alzheimer's disease, Familial British Dementia, Familial Danish Dementia, Down Syndrome, Parkinson disease and Chorea Huntington, comprising the administration of a therapeutically active amount of at least one compound of formula (I) to a mammal, preferably a human. Even preferably, the present invention provides a method of treatment and corresponding uses for the treatment of rheumatoid arthritis or atherosclerosis. Even preferably, the present invention provides a method of treatment and corresponding uses for the treatment of pancreatitis and restenosis. Pharmaceutical combinations In a preferred embodiment, the present invention provides a composition, preferably a pharmaceutical composition, comprising at least one QC inhibitor optionally in combination with at least one other agent selected from the group consisting of nootropic agents, neuroprotectants, antiparkinsonian drugs, amyloid protein deposition inhibitors, beta amyloid synthesis inhibitors, antidepressants, anxiolytic drugs, antipsychotic drugs and anti-multiple sclerosis drugs. Most preferably, said QC inhibitor is a compound of of formula (I) of the present invention. More specifically, the aforementioned other agent is selected from the group consisting PEP- inhibitors, LiCI, inhibitors of dipeptidyl aminopeptidases, preferably inhibitors of DP IV or DP IV- like enzymes; acetylcholinesterase (ACE) inhibitors, PIMT enhancers, inhibitors of beta secretases, inhibitors of gamma secretases, inhibitors of neutral endopeptidase, inhibitors of Phosphodiesterase-4 (PDE-4), TNFalpha inhibitors, muscarinic M1 receptor antagonists, NMDA receptor antagonists, sigma-1 receptor inhibitors, histamine H3 antagonists, immunomodulatory agents, immunosuppressive agents or an agent selected from the group consisting of antegren (natalizumab), Neurelan (fampridine-SR), campath (alemtuzumab), IR 208, NBI 5788/MSP 771 (tiplimotide), paclitaxel, Anergix.MS (AG 284), SH636, Differin (CD 271, adapalene), BAY 361677 (interleukin-4), matrix-metalloproteinase-inhibitors (e.g. BB 76163), interferon-tau (trophoblastin) and SAIK-MS. Further, the aforementioned other agent may be selected from the group consisting of beta- amyloid antibodies, cysteine protease inhibitors and MCP-1 antagonists. Furthermore, the other agent may be, for example, an anti-anxiety drug or antidepressant selected from the group consisting of (a) Benzodiazepines, e.g. alprazolam, chlordiazepoxide, clobazam, clonazepam, clorazepate, diazepam, fludiazepam, loflazepate, lorazepam, methaqualone, oxazepam, prazepam, tranxene, (b) Selective serotonin re-uptake inhibitors (SSRI's), e.g. citalopram, fluoxetine, fluvoxamine, escitalopram, sertraline, paroxetine, (c) Tricyclic antidepressants, e.g. amitryptiline, clomipramine, desipramine, doxepin, imipramine (d) Monoamine oxidase (MAO) inhibitors, (e) Azapirones, e.g. buspirone, tandopsirone, (f) Serotonin-norepinephrine reuptake inhibitors (SNRI's), e.g. venlafaxine, duloxetine, (g) Mirtazapine, (h) Norepinephrine reuptake inhibitors (NRI's), e.g. reboxetine, (i) Bupropione, (j) Nefazodone, (k) beta-blockers, (I) NPY-receptor ligands: NPY agonists or antagonists. In a further embodiment, the other agent may be, for example, an anti-multiple sclerosis drug selected from the group consisting of a) dihydroorotate dehydrogenase inhibitors, e.g. SC-12267, teriflunomide, MNA-715, HMR- 1279 (syn. to HMR-1715, MNA-279), b) autoimmune suppressant, e.g. laquinimod, c) paclitaxel, d) antibodies, e.g. AGT-1, anti-granulocyte-macrophage colony-stimulating factor (GM- CSF) monoclonal antibody, Nogo receptor modulators, ABT-874, alemtuzumab (CAMPATH), anti-OX40 antibody, CNTO-1275, DN-1921, natalizumab (syn. to AN- 100226, Antegren, VLA-4 Mab), daclizumab (syn. to Zenepax, Ro-34-7375, SMART anti-Tac), J-695, priliximab (syn. to Centara, CEN-000029, cM-T412), MRA, Dantes, anti-IL-12-antibody, e) peptide nucleic acid (PNA) preparations, e.g. reticulose, f) interferon alpha, e.g. Alfaferone, human alpha interferon (syn. to Omniferon, Alpha Leukoferon), g) interferon beta, e.g. Frone, interferon beta-1a like Avonex, Betron (Rebif), interferon beta analogs, interferon beta-transferrin fusion protein, recombinant interferon beta-1b like Betaseron, h) interferon tau, i) peptides, e.g. AT-008, AnergiX.MS, Immunokine (alpha-lmmunokine-NNS03), cyclic peptides like ZD-7349, j) therapeutic enzymes, e.g. soluble CD8 (sCD8), k) multiple sclerosis-specific autoantigen-encoding plasmid and cytokine-encoding plasmid, e.g. BHT-3009; I) inhibitor of TNF-alpha, e.g. BLX-1002, thalidomide, SH-636, m) TNF antagonists, e.g. solimastat, lenercept (syn. to RO-45-2081, Tenefuse), onercept (sTNFRI), CC-1069, n) TNF alpha, e.g. etanercept (syn. to Enbrel, TNR-001) o) CD28 antagonists, e.g. abatacept, p) Lck tyrosine kinase inhibitors, q) cathepsin K inhibitors, r) analogs of the neuron-targeting membrane transporter protein taurine and the plant- derived calpain inhibitor leupeptin, e.g. Neurodur, s) chemokine receptor-1 (CCR1) antagonist, e.g. BX-471, t) CCR2 antagonists, u) AMPA receptor antagonists, e.g. ER-167288-01 and ER-099487, E-2007, talampanel, v) potassium channel blockers, e.g. fampridine, w) tosyl-proline-phenylalanine small-molecule antagonists of the VLA-4/VCAM interaction, e.g. TBC-3342, x) cell adhesion molecule inhibitors, e.g. TBC-772, y) antisense oligonucleotides, e.g. EN-101, z) antagonists of free immunoglobulin light chain (IgLC) binding to mast cell receptors, e.g. F-991, aa)apoptosis inducing antigenes, e.g. Apogen MS, bb)alpha-2 adrenoceptor agonist, e.g. tizanidine (syn. to Zanaflex, Ternelin, Sirdalvo, Sirdalud, Mionidine), cc) copolymer of L-tyrosine, L-lysine, L-glutamic acid and L-alanine, e.g. glatiramer acetate (syn. to Copaxone, COP-1, copolymer-1), dd)topoisomerase II modulators, e.g. mitoxantrone hydrochloride, ee) adenosine deaminase inhibitor, e.g. cladribine (syn. to Leustatin, Mylinax, RWJ-26251), ff) interlaukin-10, e.g. ilodecakin (syn. to Tenovil, Sch-52000, CSIF), gg)interleukin-12 antagonists, e.g. lisofylline (syn. to CT-1501R, LSF, lysofylline), hh) Ethanaminum, e.g. SRI-62-834 (syn. to CRC-8605, NSC-614383), ii) immunomodulators, e.g. SAIK-MS, PNU-156804, alpha-fetoprotein peptide (AFP), IPDS, jj) retinoid receptor agonists, e.g. adapalene (syn. to Differin, CD-271), kk) TGF-beta, e.g. GDF-1 (growth and differentiation factor 1), II) TGF-beta-2, e.g. BetaKine, mm) MMP inhibitors, e.g. glycomed, nn) phosphodiesterase 4 (PDE4) inhibitors, e.g. RPR-122818, oo) purine nucleoside phosphorylase inhibitors, e.g. 9-(3-pyridylmethyl)-9-deazaguanine, peldesine (syn. to BCX-34, TO-200), pp) alpha-4/beta-1 integrin antagonists, e.g. ISIS-104278, qq)antisense alpha4 integrin (CD49d), e.g. ISIS-17044, ISIS-27104, rr) cytokine-inducing agents, e.g. nucleosides, ICN-17261, ss) cytokine inhibitors, tt) heat shock protein vaccines, e.g. HSPPC-96, uu)neuregulin growth factors, e.g. GGF-2 (syn. to neuregulin, glial growth factor 2), vv) cathepsin S - inhibitors, ww) bropirimine analogs, e.g. PNU-56169, PNU-63693, xx) Monocyte chernoattractant protein-1 inhibitors, e.g. benzimidazoles like MCP-1 inhibitors, LKS-1456, PD-064036, PD-064126, PD-084486, PD-172084, PD-172386. Further, the present invention provides pharmaceutical compositions e.g. for parenteral, enteral or oral administration, comprising at least one QC inhibitor of formula (I) optionally in combination with at least one of the other aforementioned agents. These combinations provide a particularly beneficial effect. Such combinations are therefore shown to be effective and useful for the treatment of the aforementioned diseases. Accordingly, the invention provides a method for the treatment of these conditions. The method comprises either co-administration of at least one QC inhibitor of formula (I) and at least one of the other agents or the sequential administration thereof. Co-administration includes administration of a formulation, which comprises at least one QC inhibitor of formula (I) and at least one of the other agents or the essentially simultaneous administration of separate formulations of each agent. Examples of suitable PIMT enhancers are 10-aminoaliphatyl-dibenz[b, f] oxepines described in WO 98/15647 and WO 03/057204, respectively. Further useful according to the present invention are modulators of PIMT activity described in WO 2004/039773. Inhibitors of beta secretase and compositions containing such inhibitors are described, e.g. in WO03/059346, WO2006/099352, WO2006/078576, WO2006/060109, WO2006/057983, WO2006/057945, WO2006/055434, WO2006/044497, WO2006/034296, WO2006/034277, WO2006/029850, WO2006/026204, WO2006/014944, WO2006/014762, WO2006/002004, US 7,109,217, WO2005/113484, WO2005/103043, WO2005/103020, WO2005/065195, WO2005/051914, WO2005/044830, WO2005/032471, WO2005/018545, WO2005/004803, WO2005/004802, WO2004/062625, WO2004/043916, WO2004/013098, WO03/099202, WO03/043987, WO03/039454, US 6,562,783, WO02/098849 and WO02/096897. Suitable examples of beta secretase inhibitors for the purpose of the present invention are WY- 25105 (Wyeth); Posiphen, (+)-phenserine (TorreyPines / NIH); LSN-2434074, LY-2070275, LY- 2070273, LY-2070102 (Eli Lilly & Co.); PNU-159775A, PNU-178025A, PNU-17820A, PNU- 33312, PNU-38773, PNU-90530 (Elan / Pfizer); KMI-370, KMI-358, kmi-008 (Kyoto University); OM-99-2, OM-003 (Athenagen Inc.); AZ-12304146 (AstraZeneca / Astex); GW-840736X (GlaxoSmithKline plc.) and DNP-004089 (De Novo Pharmaceuticals Ltd.). Inhibitors of gamma secretase and compositions containing such inhibitors are described, e.g. in WO2005/008250, WO2006/004880, US 7,122,675, US 7,030,239, US 6,992,081, US 6,982,264, WO2005/097768, WO2005/028440, WO2004/101562, US 6,756,511, US 6,683,091, WO03/066592, WO03/014075, WO03/013527, WO02/36555, WO01/53255, US 7,109,217, US 7,101,895, US 7,049,296, US 7,034,182, US 6,984,626, WO2005/040126, WO2005/030731, WO2005/014553, US 6,890,956, EP 1334085, EP 1263774, WO2004/101538, WO2004/00958, WO2004/089911, WO2004/073630, WO2004/069826, WO2004/039370, WO2004/031139, WO2004/031137, US 6,713,276, US 6,686,449, WO03/091278, US 6,649,196, US 6,448,229, WO01/77144 and WO01/66564. Suitable gamma secretase inhibitors for the purpose of the present invention are GSI-953, WAY-GSI-A, WAY-GSI-B (Wyeth); MK-0752, MRK-560, L-852505, L-685-458, L-852631, L- 852646 (Merck & Co. Inc.); LY-450139, LY-411575, AN-37124 (Eli Lilly & Co.); BMS-299897, BMS-433796 (Bristol-Myers Squibb Co.); E-2012 (Eisai Co. Ltd.); EHT-0206, EHT-206 (ExonHit Therapeutics SA); and NGX-555 (TorreyPines Therapeutics Inc.). Suitable beta amyloid synthesis inhibitors for the purpose of the present invention are for example Bisnorcymserine (Axonyx Inc.); (R)-flurbiprofen (MCP-7869; Flurizan) (Myriad Genetics); nitroflurbiprofen (NicOx); BGC-20-0406 (Sankyo Co. Ltd.) and BGC-20-0466 (BTG plc). Suitable amyloid protein deposition inhibitors for the purpose of the present invention are for example SP-233 (Samaritan Pharmaceuticals); AZD-103 (Ellipsis Neurotherapeutics Inc.); AAB- 001 (Bapineuzumab), AAB-002, ACC-001 (Elan Corp plc); Colostrinin (ReGen Therapeutics plc); AdPEDI-(amyloid-beta1-6)11) (Vaxin Inc.); MPI-127585, MPI-423948 (Mayo Foundation); SP-08 (Georgetown University); ACU-5A5 (Acumen / Merck); Transthyretin (State University of New York); PTI-777, DP-74, DP 68, Exebryl (ProteoTech Inc.); m266 (Eli Lilly & Co.); EGb-761 (Dr. Willmar Schwabe GmbH); SPI-014 (Satori Pharmaceuticals Inc.); ALS-633, ALS-499 (Advanced Life Sciences Inc.); AGT-160 (ArmaGen Technologies Inc.); TAK-070 (Takeda Pharmaceutical Co. Ltd.); CHF-5022, CHF-5074, CHF-5096 and CHF-5105 (Chiesi Farmaceutici SpA.). Suitable PDE-4 inhibitors for the purpose of the present invention are for example Doxofylline (Instituto Biologico Chemioterapica ABC SpA.); idudilast eye drops, tipelukast, ibudilast (Kyorin Pharmaceutical Co. Ltd.); theophylline (Elan Corp.); cilomilast (GlaxoSmithKline plc); Atopik (Barrier Therapeutics Inc.); tofimilast, Cl-1044, PD-189659, CP-220629, PDE 4d inhibitor BHN (Pfizer Inc.); arofylline, LAS-37779 (Almirall Prodesfarma SA.); roflumilast, hydroxypumafentrine (Altana AG), tetomilast (Otska Pharmaceutical Co. Ltd.); CC-10004 (Celgene Corp.); HT-0712, IPL-4088 (Inflazyme Pharmaceuticals Ltd.); MEM-1414, MEM-1917 (Memory Pharmaceuticals Corp.); oglemilast, GRC-4039 (Glenmark Pharmaceuticals Ltd.); AWD-12-281, ELB-353, ELB- 526 (Elbion AG); EHT-0202 (ExonHit Therapeutics SA.); ND-1251 (Neuro3d SA.); 4AZA-PDE4 (4 AZA Bioscience NV.); AVE-8112 (Sanofi-Aventis); CR-3465 (Rottapharm SpA.); GP-0203, NCS-613 (Centre National de la Recherche Scientifique); KF-19514 (Kyowa Hakko Kogyo Co. Ltd.); ONO-6126 (Ono Pharmaceutical Co. Ltd.); OS-0217 (Dainippon Pharmaceutical Co. Ltd.); IBFB-130011, IBFB-150007, IBFB-130020, IBFB-140301 (IBFB Pharma GmbH); IC-485 (ICOS Corp.); RBx-14016 and RBx-11082 (Ranbaxy Laboratories Ltd.). A preferred PDE-4-inhibitor is Rolipram. MAO inhibitors and compositions containing such inhibitors are described, e.g. in WO2006/091988, WO2005/007614, WO2004/089351, WO01/26656, WO01/12176, WO99/57120, W099/57119, W099/13878, WO98/40102, WO98/01157, WO96/20946, WO94/07890 and W092/21333. Suitable MAO-inhibitors for the purpose of the present invention are for example Linezolid (Pharmacia Corp.); RWJ-416457 (RW Johnson Pharmaceutical Research Institute); budipine (Altana AG); GPX-325 (BioResearch Ireland); isocarboxazid; phenelzine; tranylcypromine; indantadol (Chiesi Farmaceutici SpA.); moclobemide (Roche Holding AG); SL-25.1131 (Sanofi- Synthelabo); CX-1370 (Burroughs Wellcome Co.); CX-157 (Krenitsky Pharmaceuticals Inc.); desoxypeganine (HF Arzneimittelforschung GmbH & Co. KG); bifemelane (Mitsubishi-Tokyo Pharmaceuticals Inc.); RS-1636 (Sankyo Co. Ltd.); esuprone (BASF AG); rasagiline (Teva Pharmaceutical Industries Ltd.); ladostigil (Hebrew University of Jerusalem); safinamide (Pfizer) and NW-1048 (Newron Pharmaceuticals SpA.). Suitable histamine H3 antagonists for the purpose of the present invention are, e.g. A-331440, A-349821 (Abbott Laboratories); 3874-H1 (Aventis Pharma); UCL-2173 (Berlin Free University), UCL-1470 (BioProjet, Societe Civile de Recherche); DWP-302 (Daewoong Pharmaceutical Co Ltd); GSK-189254A, GSK-207040A (GlaxoSmithKline Inc.); cipralisant, GT-2203 (Gliatech Inc.); 1S,2S)-2-(2-Aminoethyl)-1-(1H-imidazol-4-yl)cyclopropane (Hokkaido University); JNJ-5207852 (Johnson & Johnson); NNC-0038-0000-1049 (Novo Nordisk A/S); and Sch-79687 (Schering- Plough). PEP inhibitors and compositions containing such inhibitors are described, e.g. in JP 01042465, JP 03031298, JP 04208299, WO 00/71144, US 5,847,155; JP 09040693, JP 10077300, JP 05331072, JP 05015314, WO 95/15310, WO 93/00361, EP 0556482, JP 06234693, JP 01068396, EP 0709373, US 5,965,556, US 5,756,763, US 6,121,311, JP 63264454, JP 64000069, JP 63162672, EP 0268190, EP 0277588, EP 0275482, US 4,977,180, US 5,091,406, US 4,983,624, US 5,112,847, US 5,100,904, US 5,254,550, US 5,262,431, US 5,340,832, US 4,956,380, EP 0303434, JP 03056486, JP 01143897, JP 1226880, EP 0280956, US 4,857,537, EP 0461677, EP 0345428, JP 02275858, US 5,506,256, JP 06192298, EP 0618193, JP 03255080, EP 0468469, US 5,118,811, JP 05025125, WO 9313065, JP 05201970, WO 9412474, EP 0670309, EP 0451547, JP 06339390, US 5,073,549, US 4,999,349, EP 0268281, US 4,743,616, EP 0232849, EP 0224272, JP 62114978, JP 62114957, US 4,757,083, US 4,810,721, US 5,198,458, US 4,826,870, EP 0201742, EP 0201741, US 4,873,342, EP 0172458, JP 61037764, EP 0201743, US 4,772,587, EP 0372484, US 5,028,604, WO 91/18877, JP 04009367, JP 04235162, US 5,407,950, WO 95/01352, JP 01250370, JP 02207070, US 5,221,752, EP 0468339, JP 04211648, WO 99/46272, WO 2006/058720 and PCT/EP2006/061428. Suitable prolyl endopeptidase inhibitors for the purpose of the present invention are, e.g. Fmoc- Ala-Pyrr-CN, Z-Phe-Pro-Benzothiazole (Probiodrug), Z-321 (Zeria Pharmaceutical Co Ltd.); ONO-1603 (Ono Pharmaceutical Co Ltd); JTP-4819 (Japan Tobacco Inc.) and S-17092 (Servier). Suitable examples of beta-amyloid antibodies are ACU-5A5, huC091 (Acumen/Merck); PF- 4360365, RI-1014, RI-1219, RI-409, RN-1219 (Rinat Neuroscience Corp (Pfizer Inc)); the nanobody therapeutics of Ablynx/Boehringer Ingelheim; beta-amyloid-specific humanized monoclonal antibodies of Intellect Neurosciences/IBL; m266, m266.2 (Eli Lilly & Co.); AAB-02 (Elan); bapineuzumab (Elan); BAN-2401 (Bioarctic Neuroscience AB); ABP-102 (Abiogen Pharma SpA); BA-27, BC-05 (Takeda); R-1450 (Roche); ESBA-212 (ESBATech AG); AZD- 3102 (AstraZeneca) and beta-amyloid antibodies of Mindset BioPharmaceuticals Inc. Suitable cysteine protease inhibitors are inhibitors of cathepsin B. Inhibitors of cathepsin B and compositions containing such inhibitors are described, e.g. in WO 2006/060473, WO 2006/042103, WO 2006/039807, WO 2006/021413, WO 2006/021409, WO 2005/097103, WO 2005/007199, WO2004/084830, WO 2004/078908, WO 2004/026851, WO 2002/094881, WO 2002/027418, WO 2002/021509, WO 1998/046559, WO 1996/021655. MCP-1 antagonists may, e.g. be selected from anti-MCP-1 antibodies, preferably monoclonal or humanized monoclonal antibodies, MCP-1 expression inhibitors, CCR2-antagonists, TNF-alpha inhibitors, VCAM-1 gene expression inhibitors and anti-C5a monoclonal antibodies. MCP-1 antagonists and compositions containing such inhibitors are described, e.g. in WO02/070509, WO02/081463, WO02/060900, US2006/670364, US2006/677365, WO2006/097624, US2006/316449, WO2004/056727, WO03/053368, WO00/198289, WO00/157226, WO00/046195, WO00/046196, WO00/046199, WO00/046198, WO00/046197, WO99/046991, WO99/007351, WO98/006703, WO97/012615, WO2005/105133, WO03/037376, WO2006/125202, WO2006/085961, WO2004/024921, WO2006/074265. Suitable MCP-1 antagonists are, for instance, C-243 (Telik Inc.); NOX-E36 (Noxxon Pharma AG); AP-761 (Actimis Pharmaceuticals Inc.); ABN-912, NIBR-177 (Novartis AG); CC-11006 (Celgene Corp.); SSR-150106 (Sanofi-Aventis); MLN-1202 (Millenium Pharmaceuticals Inc.); AGI-1067, AGIX-4207, AGI-1096 (AtherioGenics Inc.); PRS-211095, PRS-211092 (Pharmos Corp.); anti-C5a monoclonal antibodies, e.g. neutrazumab (G2 Therapies Ltd.); AZD-6942 (AstraZeneca plc); 2-mercaptoimidazoles (Johnson & Johnson); TEI-E00526, TEI-6122 (Deltagen); RS-504393 (Roche Holding AG); SB-282241, SB-380732, ADR-7 (GlaxoSmithKline); anti-MCP-1 monoclonal antibodies(Johnson & Johnson). Combinations of QC-inhibitors with MCP-1 antagonists may be useful for the treatment of inflammatory diseases in general, including neurodegenerative diseases. Combinations of QC-inhibitors with MCP-1 antagonists are preferred for the treatment of Alzheimer's disease. Other suitable compounds that can be used according to the present invention in combination with QC-inhibitors are NPY, a NPY mimetic or a NPY agonist or antagonist or a ligand of the NPY receptors. Preferred according to the present invention are antagonists of the NPY receptors. Suitable ligands or antagonists of the NPY receptors are 3a,4,5,9b-tetrahydro-1h-benz[e]indol- 2-yl amine-derived compounds as disclosed in WO 00/68197. NPY receptor antagonists which may be mentioned include those disclosed in European patent applications EP 0 614 911, EP 0 747 357, EP 0 747 356 and EP 0 747 378; international patent applications WO 94/17035, WO 97/19911, WO 97/19913, WO 96/12489, WO 97/19914, WO 96/22305, WO 96/40660, WO 96/12490, WO 97/09308, WO 97/20820, WO 97/20821, WO 97/20822, WO 97/20823, WO 97/19682, WO 97/25041, WO 97/34843, WO 97/46250, WO 98/03492, WO 98/03493, WO 98/03494 and WO 98/07420; WO 00/30674, US patents Nos. 5,552,411, 5,663,192 and 5,567,714; 6,114,336, Japanese patent application JP 09157253; international patent applications WO 94/00486, WO 93/12139, WO 95/00161 and WO 99/15498; US Patent No. 5,328,899; German patent application DE 393 97 97; European patent applications EP 355 794 and EP 355 793; and Japanese patent applications JP 06116284 and JP 07267988. Preferred NPY antagonists include those compounds that are specifically disclosed in these patent documents. More preferred compounds include amino acid and non- peptide-based NPY antagonists. Amino acid and non-peptide-based NPY antagonists which may be mentioned include those disclosed in European patent applications EP 0 614 911, EP 0 747 357, EP 0 747 356 and EP 0 747 378; international patent applications WO 94/17035, WO 97/19911, WO 97/19913, WO 96/12489, WO 97/19914, WO 96/22305, WO 96/40660, WO 96/12490, WO 97/09308, WO 97/20820, WO 97/20821, WO 97/20822, WO 97/20823, WO 97/19682, WO 97/25041, WO 97/34843, WO 97/46250, WO 98/03492, WO 98/03493, WO 98/03494, WO 98/07420 and WO 99/15498 ; US patents Nos. 5,552,411, 5,663,192 and 5,567,714; and Japanese patent application JP 09157253. Preferred amino acid and non- peptide-based NPY antagonists include those compounds that are specifically disclosed in these patent documents. Particularly preferred compounds include amino acid-based NPY antagonists. Amino acid- based compounds, which may be mentioned include those disclosed in international patent applications WO 94/17035, WO 97/19911, WO 97/19913, WO 97/19914 or, preferably, WO 99/15498. Preferred amino acid-based NPY antagonists include those that are specifically disclosed in these patent documents, for example BIBP3226 and, especially, (R)-N2- (diphenylacetyl)-(R)-N-[1-(4-hydroxy- phenyl) ethyl] arginine amide (Example 4 of international patent application WO 99/15498). M1 receptor agonists and compositions containing such inhibitors are described, e.g. in WO2004/087158, WO91/10664. Suitable M1 receptor antagonists for the purpose of the present invention are for example CDD- 0102 (Cognitive Pharmaceuticals); Cevimeline (Evoxac) (Snow Brand Milk Products Co. Ltd.); NGX-267 (TorreyPines Therapeutics); sabcomeline (GlaxoSmithKline); alvameline (H Lundbeck A/S); LY-593093 (Eli Lilly & Co.); VRTX-3 (Vertex Pharmaceuticals Inc.); WAY-132983 (Wyeth) and CI-101 / (PD-151832) (Pfizer Inc.). Acetylcholinesterase inhibitors and compositions containing such inhibitors are described, e.g. in WO2006/071274, WO2006/070394, WO2006/040688, WO2005/092009, WO2005/079789, WO2005/039580, WO2005/027975, WO2004/084884, WO2004/037234, WO2004/032929, WO03/101458, WO03/091220, WO03/082820, WO03/020289, WO02/32412, WO01/85145, WO01/78728, WO01/66096, WO00/02549, WO01/00215, WO00/15205, WO00/23057, WO00/33840, WO00/30446, WO00/23057, WO00/15205, WO00/09483, WO00/07600, WO00/02549, W099/47131, WO99/07359, WO98/30243, W097/38993, W097/13754, W094/29255, WO94/20476, W094/19356, WO93/03034 and W092/19238. Suitable acetylcholinesterase inhibitors for the purpose of the present invention are for example Donepezil (Eisai Co. Ltd.); rivastigmine (Novartis AG); (-)-phenserine (TorreyPines Therapeutics); ladostigil (Hebrew University of Jerusalem); huperzine A (Mayo Foundation); galantamine (Johnson & Johnson); Memoquin (Universita di Bologna); SP-004 (Samaritan Pharmaceuticals Inc.); BGC-20-1259 (Sankyo Co. Ltd.); physostigmine (Forest Laboratories Inc.); NP-0361 (Neuropharma SA); ZT-1 (Debiopharm); tacrine (Warner-Lambert Co.); metrifonate (Bayer Corp.) and INM-176 (Whanln). NMDA receptor antagonists and compositions containing such inhibitors are described, e.g. in WO2006/094674, WO2006/058236, WO2006/058059, WO2006/010965, WO2005/000216, WO2005/102390, WO2005/079779, WO2005/079756, WO2005/072705, WO2005/070429, WO2005/055996, WO2005/035522, WO2005/009421, WO2005/000216, WO2004/092189, WO2004/039371, WO2004/028522, WO2004/009062, WO03/010159, WO02/072542, WO02/34718, WO01/98262, WO01/94321, WO01/92204, WO01/81295, WO01/32640, WO01/10833, WO01/10831, WO00/56711, WO00/29023, WO00/00197, W099/53922, W099/48891, W099/45963, WO99/01416, WO99/07413, WO99/01416, WO98/50075, WO98/50044, WO98/10757, WO98/05337, W097/32873, W097/23216, W097/23215, W097/23214, W096/14318, WO96/08485, W095/31986, W095/26352, WO95/26350, W095/26349, W095/26342, W095/12594, WO95/02602, WO95/02601, WO94/20109, W094/13641, WO94/09016 and W093/25534. Suitable NMDA receptor antagonists for the purpose of the present invention are for example Memantine (Merz & Co. GmbH); topiramate (Johnson & Johnson); AVP-923 (Neurodex) (Center for Neurologic Study); EN-3231 (Endo Pharmaceuticals Holdings Inc.); neramexane (MRZ- 2/579) (Merz and Forest); CNS-5161 (CeNeS Pharmaceuticals Inc.); dexanabinol (HU-211; Sinnabidol; PA-50211) (Pharmos); EpiCept NP-1 (Dalhousie University); indantadol (V-3381; CNP-3381) (Vernalis); perzinfotel (EAA-090, WAY-126090, EAA-129) (Wyeth); RGH-896 (Gedeon Richter Ltd.); traxoprodil (CP-101606), besonprodil (PD-196860, CI-1041) (Pfizer Inc.); CGX-1007 (Cognetix Inc.); delucemine (NPS-1506) (NPS Pharmaceuticals Inc.); EVT-101 (Roche Holding AG); acamprosate (Synchroneuron LLC); CR-3991, CR-2249, CR-3394 (Rottapharm SpA.); AV-101 (4-CI-kynurenine (4-CI-KYN)), 7-chloro-kynurenic acid (7-CI-KYNA) (VistaGen); NPS-1407 (NPS Pharmaceuticals Inc.); YT-1006 (Yaupon Therapeutics Inc.); ED- 1812 (Sosei R&D Ltd.); himantane (hydrochloride N-2-(adamantly)-hexamethylen-imine) (RAMS); Lancicemine (AR-R-15896) (AstraZeneca); EVT-102, Ro-25-6981 and Ro-63-1908 (Hoffmann-La Roche AG / Evotec). DP IV-inhibitors and compositions containing such inhibitors are described, e.g. in US6,011,155; US6.107.317; US6,110,949; US6,124,305; US6.172.081; W099/61431, W099/67278, W099/67279, DE19834591, WO97/40832, WO95/15309, W098/19998, WO00/07617, WO99/38501, W099/46272, WO99/38501, WO01/68603, WO01/40180, WO01/81337, WO01/81304, WO01/55105, WO02/02560, WO01/34594, WO02/38541, WO02/083128, WO03/072556, WO03/002593, WO03/000250, WO03/000180, WO03/000181, EP1258476, WO03/002553, WO03/002531, WO03/002530, WO03/004496, WO03/004498, WO03/024942, WO03/024965, WO03/033524, WO03/035057, WO03/035067, WO03/037327, WO03/040174, WO03/045977, WO03/055881, WO03/057144, WO03/057666, WO03/068748, WO03/068757, WO03/082817, WO03/101449, WO03/101958, WO03/104229, WO03/74500, WO2004/007446, WO2004/007468, WO2004/018467, WO2004/018468, WO2004/018469, WO2004/026822, WO2004/032836, WO2004/033455, WO2004/037169, WO2004/041795, WO2004/043940, WO2004/048352, WO2004/050022, WO2004/052850, WO2004/058266, WO2004/064778, WO2004/069162, WO2004/071454, WO2004/076433, WO2004/076434, WO2004/087053, WO2004/089362, WO2004/099185, WO2004/103276, WO2004/103993, WO2004/108730, WO2004/110436, WO2004/111041, WO2004/112701, WO2005/000846, WO2005/000848, WO2005/011581, WO2005/016911, WO2005/023762, WO2005/025554, WO2005/026148, WO2005/030751, WO2005/033106, WO2005/037828, WO2005/040095, WO2005/044195, WO2005/047297, WO2005/051950, WO2005/056003, WO2005/056013, WO2005/058849, WO2005/075426, WO2005/082348, WO2005/085246, WO2005/087235, WO2005/095339, WO2005/095343, WO2005/095381, WO2005/108382, WO2005/113510, WO2005/116014, WO2005/116029, WO2005/118555, WO2005/120494, WO2005/121089, WO2005/121131, WO2005/123685, WO2006/995613; WO2006/009886; WO2006/013104; WO2006/017292; WO2006/019965; WO2006/020017; WO2006/023750; WO2006/039325; WO2006/041976; WO2006/047248; WO2006/058064; WO2006/058628; WO2006/066747; WO2006/066770 and WO2006/068978. Suitable DP IV-inhibitoirs for the purpose of the present invention are for example Sitagliptin, des-fluoro-sitagliptin (Merck & Co. Inc.); vildagliptin, DPP-728, SDZ-272-070 (Novartis) ; ABT- 279, ABT-341 (Abbott Laboratories); denagliptin, TA-6666 (GlaxoSmithKline pic); SYR-322 (Takeda San Diego Inc.); talabostat (Point Therapeutics Inc.); Ro-0730699, R-1499, R-1438 (Roche Holding AG); FE-999011 (Ferring Pharmaceuticals); TS-021 (Taisho Pharmaceutical Co. Ltd.); GRC-8200 (Glenmark Pharmaceuticals Ltd.); ALS-2-0426 (Alantos Pharmaceuticals Holding Inc.); ARI-2243 (Arisaph Pharmaceuticals Inc.); SSR-162369 (Sanofi-Synthelabo); MP- 513 (Mitsubishi Pharrna Corp.); DP-893, CP-867534-01 (Pfizer Inc.); TSL-225, TMC-2A (Tanabe Seiyaku Co. Ltd.); PHX-1149 (Phenomenix Corp.); saxagliptin (Bristol-Myers Squibb Co.); PSN-9301 ((OSI) Prosidion), S-40755 (Servier); KRP-104 (ActivX Biosciences Inc.); sulphostin (Zaidan Hojin); KR-62436 (Korea Research Institute of Chemical Technology); P32/98 (Probiodrug AG); Bl-A, Bl-B (Boehringer Ingelheim Corp.); SK-0403 (Sanwa Kagaku Kenkyusho Co. Ltd.); and NNC-72-2138 (Novo Nordisk A/S). Other preferred DP IV-inhibitors are (i) dipeptide-like compounds, disclosed in WO 99/61431, e.g. N-valyl prolyl, O-benzoyl hydroxylamine, alanyl pyrrolidine, isoleucyl thiazolidine like L-allo-isoleucyl thiazolidine, L-threo- isoleucyl pyrrolidine and salts thereof, especially the fumaric salts, and L-allo-isoleucyl pyrrolidine and salts thereof; (ii) peptide structures, disclosed in WO 03/002593, e.g. tripeptides; (iii) peptidylketones, disclosed in WO 03/033524; (vi) substituted aminoketones, disclosed in WO 03/040174; (v) topically active DP IV-inhibitors, disclosed in WO 01/14318; (vi) prodrugs of DP IV-inhibitors, disclosed in WO 99/67278 and WO 99/67279; and (v) glutaminyl based DP IV-inhibitors, disclosed in WO 03/072556 and WO 2004/099134. Most preferably the QC inhibitor is combined with one or more compounds selected from the following group: PF-4360365, m266, bapineuzumab, R-1450, Posiphen, (+)-phenserine, MK-0752, LY-450139, E-2012, (R)-flurbiprofen, AZD-103, AAB-001 (Bapineuzumab), Tramiprosate, EGb-761, TAK- 070, Doxofylline, theophylline, cilomilast, tofimilast, roflumilast, tetomilast, tipelukast, ibudilast, HT-0712, MEM-1414, oglemilast, Linezolid, budipine, isocarboxazid, phenelzine, tranylcypromine, indantadol, moclobemide, rasagiline, ladostigil, safinamide, ABT-239, ABT- 834, GSK-189254A, Ciproxifan, JNJ-17216498, Fmoc-Ala-Pyrr-CN, Z-Phe-Pro-Benzothiazole, Z-321, ONO-1603, JTP-4819, S-17092, BIBP3226; (R)-N2-(diphenylacetyl)-(R)-N-[1-(4- hydroxyphenyl) ethyl] arginine amide, Cevimeline, sabcomeline, (PD-151832), Donepezil, rivastigmine, (-)-phenserine, ladostigil, galantamine, tacrine, metrifonate, Memantine, topiramate, AVP-923, EN-3231, neramexane, valsartan, benazepril, enalapril, hydrochlorothiazide, arnlodipine, diltiazem, isradipine, nicardipine, nifedipine, nimodipine, nisoldipine, nitrendipine, verapamil, arnlodipine, acebutolol, atenolol, betaxolol, bisoprolol, carteolol, carvedilol, esmolol, labetalol, metoprolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, timolol, PLAVIX® (clopidogrel bisulfate), PLETAL® (cilostazol), aspirin, ZETIA® (ezetimibe) and KT6-971, statins, atorvastatin, pitavastatin or simvastatin; dexamethasone, cladribine, rapamycin, vincristine, taxol, aliskiren, C-243, ABN-912, SSR- 150106, MLN-1202 and betaferon. In particular, the following combinations are considered: a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with Atorvastatin for the treatment and/or prevention of artherosclerosis a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with immunosuppressive agents, preferably rapamycin for the prevention and/or treatment of restenosis a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with immunosuppressive agents, preferably paclitaxel for the prevention and/or treatment of restenosis a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with AChE inhibitors, preferably Donepezil, for the prevention and/or treatment of Alzheimer's disease a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with interferones, preferably Aronex, for the prevention and/or treatment of multiple sclerosis a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with interferones, preferably betaferon, for the prevention and/or treatment of multiple sclerosis a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with interferones, preferably Rebif, for the prevention and/or treatment of multiple sclerosis a QC inhibitor, in particular a QC inhibitor of formula (I), in combination with Copaxone, for the prevention and/or treatment of multiple sclerosis. Such a combination therapy is in particular useful for the treatment of mild cognitive impairment, Alzheimers Disease, Familial British Dementia, Familial Danish Dementia and neurodegeneration in Down syndrome as well as atherosclerosis, rheumatoid arthritis, restenosis and pancreatitis. Such combination therapies might result in a better therapeutic effect (less plaque formation, less proliferation as well as less inflammation, a stimulus for proliferation) than would occur with either agent alone. Pharmaceutical compositions To prepare the pharmaceutical compositions of this invention, at least one compound of formula (I) optionally in combination with at least one of the other aforementioned agents can be used as the active ingredient(s). The active ingredient(s) is intimately admixed with a pharmaceutical carrier according to conventional pharmaceutical compounding techniques, which carrier may take a wide variety of forms depending of the form of preparation desired for administration, e.g., oral or parenteral such as intramuscular. In preparing the compositions in oral dosage form, any of the usual pharmaceutical media may be employed. Thus, for liquid oral preparations, such as for example, suspensions, elixirs and solutions, suitable carriers and additives include water, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents and the like; for solid oral preparations such as, for example, powders, capsules, gelcaps and tablets, suitable carriers and additives include starches, sugars, diluents, granulating agents, lubricants, binders, disintegrating agents and the like. Because of their ease in administration, tablets and capsules represent the most advantageous oral dosage unit form, in which case solid pharmaceutical carriers are obviously employed. If desired, tablets may be sugar coated or enteric coated by standard techniques. For parenterals, the carrier will usually comprise sterile water, though other ingredients, for example, for purposes such as aiding solubility or for preservation, may be included. Injectable suspensions may also prepared, in which case appropriate liquid carriers, suspending agents and the like may be employed. The pharmaceutical compositions herein will contain, per dosage unit, e.g., tablet, capsule, powder, injection, teaspoonful and the like, an amount of the active ingredient(s) necessary to deliver an effective dose as described above. The pharmaceutical compositions herein will contain, per dosage unit, e.g., tablet, capsule, powder, injection, suppository, teaspoonful and the like, from about 0.03 mg to 100 mg/kg (preferred 0.1 - 30 mg/kg) and may be given at a dosage of from about 0.1 - 300 mg/kg per day (preferred 1 - 50 mg/kg per day) of each active ingredient or combination thereof. The dosages, however, may be varied depending upon the requirement of the patients, the severity of the condition being treated and the compound being employed. The use of either daily administration or post- periodic dosing may be employed. Preferably these compositions are in unit dosage forms from such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, metered aerosol or liquid sprays, drops, ampoules, autoinjector devices or suppositories; for oral parenteral, intranasal, sublingual or rectal administration, or for administration by inhalation or insufflation. Alternatively, the composition may be presented in a form suitable for once-weekly or once-monthly administration; for example, an insoluble salt of the active compound, such as the decanoate salt, may be adapted to provide a depot preparation for intramuscular injection. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical carrier, e.g. conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, and other pharmaceutical diluents, e.g. water, to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a pharmaceutically acceptable salt thereof. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective dosage forms such as tablets, pills and capsules. This solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0.1 to about 500 mg of each active ingredient or combinations thereof of the present invention. The tablets or pills of the compositions of the present invention can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of material can be used for such enteric layers or coatings, such materials including a number of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate. This liquid forms in which the compositions of the present invention may be incorporated for administration orally or by injection include, aqueous solutions, suitably flavoured syrups, aqueous or oil suspensions, and flavoured emulsions with edible oils such as cottonseed oil, sesame oil, coconut oil or peanut oil, as well as elixirs and similar pharmaceutical vehicles. Suitable dispersing or suspending agents for aqueous suspensions, include synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinylpyrrolidone or gelatin. The pharmaceutical composition may contain between about 0.01 mg and 100 mg, preferably about 5 to 50 mg, of each compound, and may be constituted into any form suitable for the mode of administration selected. Carriers include necessary and inert pharmaceutical excipients, including, but not limited to, binders, suspending agents, lubricants, flavorants, sweeteners, preservatives, dyes, and coatings. Compositions suitable for oral administration include solid forms, such as pills, tablets, caplets, capsules (each including immediate release, timed release and sustained release formulations), granules, and powders, and liquid forms, such as solutions, syrups, elixirs, emulsions, and suspensions. Forms useful for parenteral administration include sterile solutions, emulsions and suspensions. Advantageously, compounds of the present invention may be administered in a single daily dose, or the total daily dosage may be administered in divided doses of two, three or four times daily. Furthermore, compounds for the present invention can be administered in intranasal form via topical use of suitable intranasal vehicles, or via transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of transdermal delivery system, the dosage administration will, of course, be continuous rather than intermittent throughout the dosage regimen. For instance, for oral administration in the form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic pharmaceutically acceptable inert carrier such as ethanol, glycerol, water and the like. Moreover, when desired or necessary, suitable binders; lubricants, disintegrating agents and coloring agents can also be incorporated into the mixture. Suitable binders include, without limitation, starch, gelatin, natural sugars such as glucose or betalactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like. The liquid forms in suitable flavored suspending or dispersing agents such as the synthetic and natural gums, for example, tragacanth, acacia, methyl-cellulose and the like. For parenteral administration, sterile suspensions and solutions are desired. Isotonic preparations which generally contain suitable preservatives are employed when intravenous administration is desired. The compounds or combinations of the present invention can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine or phosphatidylcholines. Compounds or combinations of the present invention may also be delivered by the use of monoclonal antibodies as individual carriers to which the compound molecules are coupled. The compounds of the present invention may also be coupled with soluble polymers as targetable drug carriers. Such polymers can include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamidephenol, polyhydroxyethylaspartamid-ephenol, or polyethyl eneoxidepolyllysine substituted with palmitoyl residue. Furthermore, the compounds of the present invention may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polyactic acid, polyepsilon caprolactone, polyhydroxy butyeric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross- linked or amphipathic block copolymers of hydrogels. Compounds or combinations of this invention may be administered in any of the foregoing compositions and according to dosage regimens established in the art whenever treatment of the addressed disorders is required. The daily dosage of the products may be varied over a wide range from 0.01 to 1.000 mg per mammal per day. For oral administration, the compositions are preferably provided in the form of tablets containing, 0.01, 0.05, 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0, 25.0, 50.0, 100, 150, 200, 250 and 500 milligrams of each active ingredient or combinations thereof for the symptomatic adjustment of the dosage to the patient to be treated. An effective amount of the drug is ordinarily supplied at a dosage level of from about 0.1 mg/kg to about 300 mg/kg of body weight per day. Preferably, the range is from about 1 to about 50 mg/kg of body weight per day. The compounds or combinations may be administered on a regimen of 1 to 4 times per day. Optimal dosages to be administered may be readily determined by those skilled in the art, and will vary with the particular compound used, the mode of administration, the strength of the preparation, the mode of administration, and the advancement of disease condition. In addition, factors associated with the particular patient being treated, including patient age, weight, diet and time of administration, will result in the need to adjust dosages. In a further aspect, the invention also provides a process for preparing a pharmaceutical composition comprising at least one compound of formula (I) optionally in combination with at least one of the other aforementioned agents and a pharmaceutically acceptable carrier. The compositions are preferably in a unit dosage form in an amount appropriate for the relevant daily dosage. Suitable dosages, including especially unit dosages, of the the compounds of the present invention include the known dosages including unit doses for these compounds as described or referred to in reference text such as the British and US Pharmacopoeias, Remington's Pharmaceutical Sciences (Mack Publishing Co.), Martindale The Extra Pharmacopoeia (London, The Pharmaceutical Press) (for example see the 31st Edition page 341 and pages cited therein) or the above mentioned publications. Synthesis of the examples Synthesis scheme 1: The compounds were synthesized according the general synthesis scheme 1 and their identity was confirmed by mass spectrometry. Scheme 1 Amine (IV), 50 ul 0.2M, in methanol (dry) was dispensed on 96-well plates. Aldehyde (Va), 50 ul 0.2M in methanol (dry) was then added. The well plates were stacked for 30 minutes at room temperature. Subsequently isocyanide (III), 50 ul 0.2 M, in methanol (dry) and 50 ul 1M Trimethylsilylazide was added. The well plates were sealed and stacked for 48 hours at room temperature. After completion, the solvent was evaporated. All compounds were immediately tested regarding their activity as hQC inhibitors. IC5o values were found to be in the range of 0.01 to 10 uM when tested directly following synthesis (i.e. without purification). Detailed synthesis description Certain compounds of the invention were prepared by preparative synthesis following essentially the route used for the parallel synthesis. General workup The appropriate amine (IV) (1 mmol) and aldehyde (Va) (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and the appropriate isocyanide (III) (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. The purity of the compounds was determined by HPLC-MS. The IC5o value against hQC was measured using the fluorescent assay. Purification and characterisation The resulting crude reaction products were purified in an automatic process using a semi- preparative HPLC-MS with mass-triggered sampling of the desired peak: Purification via semi-preparative HPLC-MS Instrumentation: 2 x Varian PrepStar SD-1 1x Dionex P580 Pump 1 Channel(MakeUP I) 1x Dionex AXP-MS (MakeUP II) 1x Dionex MSQ 1x Dionex UVD 340V - Prep Flow Cell Gilson 215 Liquid Handler Column: SunFire Prep C18 OBD 5 urn 19x50mm Method: Column Flow: 30 ml/min Solvent A: methanol, 0,3% acetic acid Solvent B: water, 0,3 % acetic acid Time table for gradient: 20 Detection: UV 254nm, Mass Spectrometer Detector (API-ES, positive) Compound verfication The compound verification via analytical HPLC1-4S was done after purification using the following instrumentation, column and method: Analytical method for compound purity Instrumentation: Agilent MSD 1100 Column: YMCODS-A 2.1x50, 3um Method: Column Flow: 0.600 ml/min Solvent A: acetonitrile,0.5% acetic acid Solvent B: 90% water, 10% acetonitrile, 0,5 % acetic acid Time table for gradient: Detection: UV 254nm, Mass Spectrometer Detector (API-ES, positive) Compound 3: 2-[[1 -(4-Chloro-benzyl)-1 H-tetrazol-5-yl]-(3-imidazol-1 -yl-propylamino)- methyl]-4-methyl-phenol 3-lmidazol-1-yl-propylamine (1 mmol) and 2-Hydroxy-5-methyl-benzaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and 1-Chloro-4- isocyanomethyl-benzene (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 437.94 RT - UV254nm (min): 2.84 IC50 hQC(nM): 584 Compound 6: [[1 -(4-Chloro-benzyl)-1 H-tetrazol-5-yl]-(1 H-indol-5-yl)-methyl]-(3- imidazol-1-yl-propyl)-amine 3-lmidazol-1-yl-propylamine (1 mmol) and 1H-lndole-5-carbaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and 1-Chloro-4- isocyanomethyl-benzene (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 446.95 RT - UV254nm (min): 2.70 IC50 hQC(nM): 450 Compound 28: [(1 -Cyclopentyl-1 H-tetrazol-5-yl)-(3,4-dihydro-2H-pyran-2-yl)- methyl]-(3-imidazol-1 -yl-propyl)-amine 3-lmidazol-1-yl-propylamine (1 mmol) and 3,4-Dihydro-2H-pyran-2-carbaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and Isocyano-cyclopentan (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 357.46 RT - UV254nm (min): 2.66 IC50 hQC(nM): 3468 Compound 38: {(3,4-Dihydro-2H-pyran-2-yl)-[1 -(2-dimethylamino-ethyl)-1 H- tetrazol-5-yl]-methyl}-(3-imidazol-1 -yl-propyl)-amine 3-lmidazol-1-yl-propylamine (1 mmol) and 3,4-Dihydro-2H-pyran-2-carbaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and (2- lsocyano-ethyl)-dimethyl-amine (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 360.47 RT - UV254nm (min): 0.33 IC50 hQC(nM): 2880 Compound 63: 2-[[1 -(2,2-Dimethyl-propyl)-1 H-tetrazol-5-yl]-(3-imida2ol-1 -yl- propylamino)-methyl]-4-methyl-phenol 3-lmidazol-1-yl-propylamine (1 mmol) and 2-Hydroxy-5-methyl-benzaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and 1-lsocyano- 2,2-dimethyl-propane (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 383.50 RT - UV254nm (min): 2.63 IC50 hQC(nM): 2368 Compound 64: 2-[[1 -(2,2-Dimethyl-propyl)-1 H-tetrazol-5-yl]-(3-imidazol-1 -yl- propylamino)-methyl]-quinolin-8-ol 3-lmidazol-1-yl-propylamine (1 mmol) and 8-Hydroxy-quinoline-2-carbaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and 1- lsocyano-2,2-dimethyl-propane (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 420.52 RT-UV254nm(min): 2.93 IC50 hQC(nM): 1030 Compound 68: 2-[(1 -Cyclopropyl-1 H-tetrazol-5-yl)-(3-imidazol-1 -yl-propylamino)- methyl]-4-methyl-phenol 3-lmidazol-1-yl-propylamine (1 mmol) and 2-Hydroxy-5-methyl-benzaldehyde (1 mmol) were combined in methanol (2 ml, dry). After 2 hours Trimethylsilylazide (5mmol) and Isocyano- cyclopropane (1mmol) was added. The reaction was stirred at room temperature for 48h. After evaporation of the solvent the residue was purified with chromatographic methods. molecular weight (g/mol): 353.43 RT - UV254nm (min): 1.10 IC50 hQC(nM): 668 Examples of the invention Example 1: Assays for glutaminyl cyclase activity Fluorometric assays All measurements were performed with a BioAssay Reader HTS-7000Plus for microplates (Perkin Elmer) at 30 °C. QC activity was evaluated fluorometrically using H-Gln-(3NA. The samples consisted of 0.2 mM fluorogenic substrate, 0.25 U pyroglutamyl aminopeptidase (Unizyme, Horsholm, Denmark) in 0.2 M Tris/HCI, pH 8.0 containing 20 mM EDTA and an appropriately diluted aliquot of QC in a final volume of 250 ul. Excitation/emission wavelengths were 320/410 nm. The assay reactions were initiated by addition of glutaminyl cyclase. QC activity was determined from a standard curve of β-naphthylamine under assay conditions. One unit is defined as the amount of QC catalyzing the formation of 1 μmol pGlu- (3NA from H-Gln-pNA per minute under the described conditions. In a second fluorometric assay, QC was activity determined using H-Gln-AMC as substrate. Reactions were carried out at 30°C utilizing the NOVOStar reader for microplates (BMG labtechnologies). The samples consisted of varying concentrations of the fluorogenic substrate, 0.1 U pyroglutamyl aminopeptidase (Qiagen) in 0.05 M Tris/HCI, pH 8.0 containing 5 mM EDTA and an appropriately diluted aliquot of QC in a final volume of 250 ul. Excitation/emission wavelengths were 380/460 nm. The assay reactions were initiated by addition of glutaminyl cyclase. QC activity was determined from a standard curve of 7-amino- 4-methylcoumarin under assay conditions. The kinetic data were evaluated using GraFit sofware. Spectrophotometric assay of QC This novel assay was used to determine the kinetic parameters for most of the QC substrates. QC activity was analyzed spectrophotometrically using a continuous method, that was derived by adapting a previous discontinuous assay (Bateman, R. C. J. 1989 J Neurosci Methods 30, 23-28) utilizing glutamate dehydrogenase as auxiliary enzyme. Samples consisted of the respective QC substrate, 0.3 mM NADH, 14 mM a-Ketoglutaric acid and 30 U/ml glutamate dehydrogenase in a final volume of 250 ul. Reactions were started by addition of QC and persued by monitoring of the decrease in absorbance at 340 nm for 8-15 min. The initial velocities were evaluated and the enzymatic activity was determined from a standard curve of ammonia under assay conditions. All samples were measured at 30°C, using either the SPECTRAFIuor Plus or the Sunrise (both from TECAN) reader for microplates. Kinetic data was evaluated using GraFit software. Inhibitor assay For inhibitor testing, the sample composition was the same as described above, except of the putative inhibitory compound added. For a rapid test of QC-inhibition, samples contained 4 mM of the respective inhibitor and a substrate concentration at 1 KM. For detailed investigations of the inhibition and determination of Ki-values, influence of the inhibitor on the auxiliary enzymes was investigated first. In every case, there was no influence on either enzyme detected, thus enabling the reliable determination of the QC inhibition. The inhibitory constant was evaluated by fitting the set of progress curves to the general equation for competitive inhibition using GraFit software. Example 2: MALDI-TOF mass spectrometry Matrix-assisted laser desorption/ionization mass spectrometry was carried out using the Hewlett-Packard G2025 LD-TOF System with a linear time of flight analyzer. The instrument was equipped with a 337 nm nitrogen laser, a potential acceleration source (5 kV) and a 1.0 m flight tube. Detector operation was in the positive-ion mode and signals are recorded and filtered using LeCroy 9350M digital storage oscilloscope linked to a personal computer. Samples (5 μl) were mixed with equal volumes of the matrix solution. For matrix solution DHAP/DAHC was used, prepared by solving 30 mg 2',6'-dihydroxyacetophenone (Aldrich) and 44 mg diammonium hydrogen citrate (Fluka) in 1 ml acetonitrile/0.1% TFA in water (1/1, v/v). A small volume (= 1 μl) of the matrix-analyte-mixture was transferred to a probe tip and immediately evaporated in a vacuum chamber (Hewlett-Packard G2024A sample prep accessory) to ensure rapid and homogeneous sample crystallization. For long-term testing of Glu1-cyclization, Aβ-derived peptides were incubated in 100μl 0.1 M sodium acetate buffer, pH 5.2 or 0.1 M Bis-Tris buffer, pH 6.5 at 30°C. Peptides were applied in 0.5 mM [A0(3-11)a] or 0.15 mM [Ap(3-21)a] concentrations, and 0.2 U QC is added all 24 hours. In case of A(3(3-21)a, the assays contained 1 % DMSO. At different times, samples are removed from the assay tube, peptides extracted using ZipTips (Millipore) according to the manufacturer's recommendations, mixed with matrix solution (1:1 v/v) and subsequently the mass spectra recorded. Negative controls either contain no QC or heat deactivated enzyme. For the inhibitor studies the sample composition was the same as described above, with exception of the inhibitory compound added (5 mM or 2 mM of a test compound of formula (I)). The first QC inhibitors were disclosed in WO 2004/098591 and WO 2005/075436. There are no other potent QC inhibitors known in the art. The same holds true for combinations and compositions for the treatment of neuronal diseases comprising QC inhibitors. Compounds and combinations of the invention may have the advantage that they are, for example, more potent, more selective, have fewer side-effects, have better formulation and stability properties, have better pharmacokinetic properties, be more bioavailable, be able to cross blood brain barrier and are more effective in the brain of mammals, are more compatible or effective in combination with other drugs or be more readily synthesized than other compounds of the prior art. Throughout the specification and the claims which follow, unless the context requires otherwise, the word 'comprise', and variations such as 'comprises' and 'comprising', will be understood to imply the inclusion of a stated integer, step, group of integers or group of steps but not to the exclusion of any other integer, step, group of integers or group of steps. All patents and patent applications mentioned throughout the specification of the present invention are herein incorporated in their entirety by reference. The invention embraces all combinations of preferred and more preferred groups and embodiments of groups recited above. Claims 1. A compound of formula (I) wherein R1 represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl; R2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, -C(O)O-alkyl and -C(O)OH; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)O- alkyl and -C(O)OH; alkenyl; alkynyl; -alkyl-aryl; -alkyl-heteroaryl; -alkyl-heterocyclyl; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -heteroaryl-heteroaryl; -aryl-aryl; -aryl; heteroaryl; heterocyclyl; or R2 together with R4 may form a carbocyclyl group optionally substituted by one or more alkyl groups; R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O- alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O-alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, - alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxyl and oxo; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -aryl-O-aryl; - heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl-C(O)-NH-alkyl-aryl;-alkyl-C(O)-NH-alkyl-heteroaryl;-a!kyl-C(O)-NH-alkyl- heterocyclyl; -alkyl-C(O)-(N-piperidinyl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl; R4 represents H or alkyl; or a pharmaceutically acceptable salt or solvate thereof, including all tautomers and stereoisomers thereof. 2. A compound according to claim 1 wherein the following compounds are excluded from the scope of formula (I) 3. A compound according to claim 1 or claim 2, wherein R1 represents -alkylheteroaryl. 4. A compound according to claim 3, wherein heteroaryl is 5 or 6 membered monocyclic heteroaryl. 5. A compound according to claim 4, wherein R1 represents 3-imidazol-1-yl-propyl. 6. A compound according to claim 1 or claim 2, wherein R1 represents -heteroaryl. 7. A compound according to claim 6 wherein R1 represents bicyclic heteroaryl. 8. A compound according to claim 7, wherein R1 represents 1 H-benzoimidazol-5-yl. 9. A compound according to any of the preceding claims, wherein R2 represents alkyl, which may optionally be substituted by one or more groups selected from -thioalkyl and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from -alkyl, -thioalkyl and -C(O)O-alkyl; alkenyl; -alkyl-aryl; -alkyl- heteroaryl; -aryl heteroaryl; -aryl; heteroaryl; heterocyclyl; or R2 together with R4 represents carbocyclyl. 10. A compound according to claim 9, wherein R2 represents -aryl-heteroaryl, aryl or heteroaryl; or R2 together with R4 represents cycloalkyl. 11. A compound according to claim 10, wherein R2 represents aryl. 12. A compound according to claim 10, wherein R2 represents heteroaryl. 13. A compound according to claim 10, wherein R2 together with R4 represents cycloalkyl. 14. A compound according to any one of claims 1 to 12 wherein R4 represents H. 15. A compound according to any of claims 1 to 14, wherein R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O-alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl- heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxyl and oxo; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl- alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl-C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH-alkyl-heterocyclyl; -alkyl-C(O)-(N-piperidinyl) or -alkyl-C(O)-(N- pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. 16. A compound according to any of claims 1 to 15, wherein R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, alkoxy-, and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, alkoxy-, and -C(O)O-alkyl; alkenyl; -alkyl-aryl; -alkyl(aryl)2, -alkyl-heteroaryl; -alkyl-heterocyclyl; -aryl; heteroaryl (monocyclic or bicyclic); -aryl-O-aikyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)NH-(N- piperidinyl) in which piperidinyl or pyrrolidinyl may be fused to optionally substituted phenyl. 17. A compound according to claim 16, wherein R3 represents alkyl, which may optionally be substituted by -C(O)Oalkyl or -alkoxy; cycloalkyl, which may optionally be substituted by alkyl or-C(O)Oalkyl; -aryl-O-alkyl-aryl; -alkyl-aryl; -alkyl-heteroaryl; -alkyl-heterocyclyl; -alkyl-C(O)-N-alkyl-aryl. 18. A compound according to claim 17, wherein R3 represents unsubstituted alkyl. 19. A compound according to claim 17, wherein R3 represents alkyl substituted by -C(O)Oalkyl. 20. A compound according to claim 17, wherein R3 represents -alkyl-aryl. 21. A compound according to claim 17, wherein R3 represents -alkyl-heteroaryl. 22. A compound as defined in examples 1-212 or a pharmaceutically acceptable salt or solvate of any one thereof. 23. A compound as defined in example 1, 6, 7, 12, 14,19, 20, 25, 34, 49, 51, 55, 59, 63, 64, 72, 74, 75, 77, 78, 85, 87, 90, 102, 109, 119, 142, 145, 147, 148, 160, 166, 177, 181, 187, 190, 197, 199,200,203,205,208,210,211 or 212 or a pharmaceutically acceptable salt or solvate of any one thereof. 24. A compound according to claims 1 to 23 for use as a medicament. 25. A pharmaceutical composition comprising a compound according to any one of claims 1 to 24 optionally in combination with one or more therapeutically acceptable diluents or carriers. 26. The pharmaceutical composition of claim 25, which comprises additionally at least one compound, selected from the group consisting of neuroprotectants, antiparkinsonian drugs, amyloid protein deposition inhibitors, beta amyloid synthesis inhibitors, antidepressants, anxiolytic drugs, antipsychotic drugs and anti-multiple sclerosis drugs. 27. The pharmaceutical composition of claim 25 or 26, which comprises additionally at least one compound, selected from the group consisting of PEP-inhibitors, LiCI, inhibitors of dipeptidyl aminopeptidases, preferably inhibitors of DP IV or DP IV-like enzymes, acetylcholinesterase (ACE) inhibitors, PIMT enhancers, inhibitors of beta secretases, inhibitors of gamma secretases, inhibitors of neutral endopeptidase, inhibitors of Phosphodiesterase-4 (PDE-4), TNFalpha inhibitors, muscarinic M1 receptor antagonists, NMDA receptor antagonists, sigma-1 receptor inhibitors, histamine H3 antagonists, immunomodulatory agents, immunosuppressive agents, beta-amyloid antibodies, cysteine protease inhibitors, MCP-1 antagonists or an agent selected from the group consisting of antegren (natalizumab), Neurelan (fampridine- SR), campath (alemtuzumab), IR 208, NBI 5788/MSP 771 (tiplimotide), paclitaxel, Anergix.MS (AG 284), SH636, Differin (CD 271, adapalene), BAY 361677 (interleukin-4), matrix-metalloproteinase-inhibitors (e.g. BB 76163), interferon-tau (trophoblastin) and SAIK-MS. 28. A compound according to any one of claims 1 to 23 or a pharmaceutical composition according to any one of claims 25 to 27 for use in the treatment of a disease selected from the group consisting of Kennedy's disease, duodenal cancer with or w/o Helicobacter pylori infections, colorectal cancer, Zolliger-Ellison syndrome, gastric cancer with or without Helicobacter pylori infections, pathogenic psychotic conditions, schizophrenia, infertility, neoplasia, inflammatory host responses, cancer, malign metastasis, melanoma, psoriasis, impaired humoral and cell-mediated immune responses, leukocyte adhesion and migration processes in the endothelium, impaired food intake, impaired sleep-wakefulness, impaired homeostatic regulation of energy metabolism, impaired autonomic function, impaired hormonal balance or impaired regulation of body fluids, multiple sclerosis, the Guillain-Barre syndrome and chronic inflammatory demyelinizing polyradiculoneuropathy. 29. A compound according to any one of claims 1 to 23 or a pharmaceutical composition according to any one of claims 25 to 27 for use in the treatment of a disease selected from the group consisting of mild cognitive impairment, Alzheimer's disease, Familial British Dementia, Familial Danish Dementia, Down Syndrome and Huntington's disease. 30. A compound according to any one of claims 1 to 23 or a pharmaceutical composition according to any one of claims 25 to 26 for use in the treatment of a disease selected from rheumatoid arthritis, atherosclerosis, pancreatitis or restenosis. 31. A method of treatment or prevention of a disease selected from the group consisting of Kennedy's disease, ulcer disease, duodenal cancer with or w/o Helicobacter pylori infections, colorectal cancer, Zolliger-Ellison syndrome, gastric cancer with or without Helicobacter pylori infections, pathogenic psychotic conditions, schizophrenia, infertility, neoplasia, inflammatory host responses, cancer, malign metastasis, melanoma, psoriasis, impaired humoral and cell-mediated immune responses, leukocyte adhesion and migration processes in the endothelium, impaired food intake, impaired sleep-wakefulness, impaired homeostatic regulation of energy metabolism, impaired autonomic function, impaired hormonal balance or impaired regulation of body fluids, multiple sclerosis, the Guillain-Barre syndrome and chronic inflammatory demyelinizing polyradiculoneuropathy, which comprises administering to a subject an effective amount of a compound according to any one of claims 1 to 23 or a pharmaceutical composition according to any one of claims 25 to 27. 32. A method of treatment or prevention of a disease selected from the group consisting of mild cognitive impairment, Alzheimer's disease, Familial British Dementia, Familial Danish Dementia, Down Syndrome and Huntington's disease, which comprises administering to a subject an effective amount of a compound according to any one of claims 1 to 23 or a pharmaceutical composition according to any one of claims 25 to 27. 33. A method of treatment or prevention of a disease selected from rheumatoid arthritis, atherosclerosis, pancreatitis or restenosis, which comprises administering to a subject an effective amount of a compound according to any one of claims 1 to 23 or a pharmaceutical composition according to any one of claims 25 to 27. 34. Use of a compound according to any one of claims 1 to 23 in the manufacture of a medicament for the treatment of a disease selected from the group consisting of Kennedy's disease, ulcer disease, duodenal cancer with or w/o Helicobacter pylori infections, colorectal cancer, Zolliger-Ellison syndrome, gastric cancer with or without Helicobacter pylori infections, pathogenic psychotic conditions, schizophrenia, infertility, neoplasia, inflammatory host responses, cancer, malign metastasis, melanoma, psoriasis, impaired humoral and cell-mediated immune responses, leukocyte adhesion and migration processes in the endothelium, impaired food intake, impaired sleep-wakefulness, impaired homeostatic regulation of energy metabolism, impaired autonomic function, impaired hormonal balance or impaired regulation of body fluids, multiple sclerosis, the Guillain-Barre syndrome and chronic inflammatory demyelinizing polyradiculoneuropathy. 35. Use of a compound according to any one of claims 1 to 23 in the manufacture of a medicament for the treatment of a disease selected from the group consisting of mild cognitive impairment, Alzheimer's disease, Familial British Dementia, Familial Danish Dementia, Down Syndrome and Huntington's disease. 36. Use of a compound according to any one of claims 1 to 23 in the manufacture of a medicament for the treatment of a disease selected from rheumatoid arthritis, atherosclerosis, pancreatitis or restenosis. 37. A process for preparation of compounds of formula (I) or a protected derivative thereof comprises reaction of a compound of formula (II) or a protected derivative thereof, wherein R1 and R2 are as defined in claims 1 to 23, with a suitable azide such as trimethylsilylazide and a compound of formula (III) or a protected derivative thereof, wherein R3 is as defined in claims 1 to 23. The present invention relates to compounds of formula (I), combinations and uses thereof for disease therapy, wherein: Rl represents heteroaryl, -carbocyclyl-heteroaryl, -alkenylheteroaryl or -alkylheteroaryl; R2 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, -alkoxy, -thioalkyl, -C(O)O-alkyl and -C(O)OH; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, haloalkyl, amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)O-alkyl and -C(O)OH; alkenyl; alkynyl; -alkyl-aryl; -alkyl-heteroaryl; -alkyl-heterocyclyl; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -heteroaryl-heteroaryl; -aryl-aryl; -aryl (monocyclic or bicyclic); heteroaryl (monocyclic or bicyclic); heterocyclyl; or R2 together with R4 may form a carbocyclyl group optionally substituted by one or more alkyl groups; R3 represents alkyl, which may optionally be substituted by one or more groups selected from amino, halogen, hydroxyl, alkoxy-, -thioalkyl, -C(O)OH and -C(O)O-alkyl; carbocyclyl, which may optionally be substituted by one or more groups selected from alkyl, amino, halogen, haloalkyl, hydroxyl, -alkoxy, -thioalkyl, -C(O)OH and -C(O)O-alkyl; alkenyl; -alkyl- aryl; -alkyl(aryl)2, -alkyl(heteroaryl)2, -alkyl(aryl)(heteroaryl), -alkyl-heteroaryl; -alkyl-heterocyclyl which heterocyclyl group may optionally be substituted by one or more groups selected from alkyl, hydroxy and oxo; -alkyl-carbocyclyl; -aryl-heteroaryl; -heteroaryl-aryl; -aryl-aryl; -aryl-O-aryl, -heteroaryl-heteroaryl; -aryl; heteroaryl; heterocyclyl; -aryl-alkyl-aryl; -aryl-O-alkyl-aryl; -alkyl-C(O)-NH-alkyl-aryl; -alkyl-C(O)-NH-alkyl-heteroaryl; -alkyl-C(O)-NH- alkyl-heterocyclyl; -alkyl-C(O)-(N-piperidinyl) or -alkyl-C(O)-(N-pyrrolidinyl) in which piperidinyl or pyrrolidinyl may optionally be fused to optionally substituted phenyl. R4 represents H or alkyl.

Documents:

1412-KOLNP-2009-(10-10-2014)-ABSTRACT.pdf

1412-KOLNP-2009-(10-10-2014)-AMANDED CLAIMS.pdf

1412-KOLNP-2009-(10-10-2014)-ANNEXURE TO FORM 3.pdf

1412-KOLNP-2009-(10-10-2014)-CORRESPONDENCE.pdf

1412-KOLNP-2009-(10-10-2014)-FORM-2.pdf

1412-KOLNP-2009-(10-10-2014)-GPA.pdf

1412-KOLNP-2009-(10-10-2014)-OTHERS.pdf

1412-KOLNP-2009-(10-10-2014)-PETITION UNDER RULE 137.pdf

1412-kolnp-2009-abstract.pdf

1412-KOLNP-2009-ANEXURE TO FORM 3.pdf

1412-KOLNP-2009-ASSIGNMENT.pdf

1412-kolnp-2009-claims.pdf

1412-KOLNP-2009-CORRESPONDENCE-1.1.pdf

1412-kolnp-2009-correspondence.pdf

1412-kolnp-2009-description (complete).pdf

1412-kolnp-2009-form 1.pdf

1412-KOLNP-2009-FORM 18.pdf

1412-kolnp-2009-form 3.pdf

1412-kolnp-2009-form 5.pdf

1412-kolnp-2009-international publication.pdf

1412-KOLNP-2009-PA.pdf

1412-kolnp-2009-pct priority document notification.pdf

1412-kolnp-2009-pct request form.pdf

1412-kolnp-2009-sequence listing.pdf

1412-kolnp-2009-specification.pdf

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