Title of Invention	NOVEL COMPOUNDS FOR TREATING MENTAL DISORDERS, AND PREPARATION AND USES THEREOF
Abstract	The present invention relates to a compound of formula (I), an optical isomer or a pharmaceutically acceptable salt thereof, its preparation and uses, wherein R is defined as herein. Such compounds can be presented as an optical isomer or a racemic mixture. The compounds can be metabolized in vivo to form a pharmacologically active substance as antagonist of neurotransmitters, and can be used for the treatment of the related mental disorders such as schizophrenia.

Title of Invention

NOVEL COMPOUNDS FOR TREATING MENTAL DISORDERS, AND PREPARATION AND USES THEREOF

Abstract

The present invention relates to a compound of formula (I), an optical isomer or a pharmaceutically acceptable salt thereof, its preparation and uses, wherein R is defined as herein. Such compounds can be presented as an optical isomer or a racemic mixture. The compounds can be metabolized in vivo to form a pharmacologically active substance as antagonist of neurotransmitters, and can be used for the treatment of the related mental disorders such as schizophrenia.

Full Text	NOVEL COMPOUNDS FOR TREATING MENTAL DISORDERS. AND PREPARATION AND USES THEREOF TECHNICAL FIELD OF THE INVENTION The present invention relates to a compound of formula (I) and salts thereof, a process for preparing the same, a pharmaceutical composition comprising the same, and their use for the treatment or auxiliary treatment of mental disorders. BACKGROUND OF THE INVENTION It has been reported that the compound [formula (II)] [3-{2-[4-(6-fluoro-benzo[d]isoxazol-3-yl)piperidin-1-yl]-ethyl}-9-hydroxy-2-methyl- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one; or IUPAC name: 3-[2-[4-(6-fluorobenzo[d]isoxazol-3-yl)-1-piperidyl]ethyl]-7-hydroxy-4-methyl-1,5- diazabicyclo[4.4.0]deca-3,5-dien-2-one; CAS Nr. 144598-75-4; MW 426.48; Paliperidone or 9-OH risperidone or 9-hydroxy risperidone] is a benzoisoxazole derivative and one of new generation antipsychotics. The compound [formula (II)] is a selective monoaminergic antagonist having unique properties, and has a high affinity to serotoninergic 5-HT2 receptor and dopamine D2 receptor. The compound [formula (II)] can also binds to a1-adrenergic receptor, and binds to histaminergic H1 receptor and a2-adrenoceptor with a relatively low affinity. The compound [formula (II)] does not bind to a cholinergic receptor. The compound [formula (II)] is a potent D2 antagonist and can improve positive symptoms of schizophrenia, but it may cause less motor function inhibition and catalepsy than classic antipsychotics. Its balanced antagonistic effects on serotonin and dopamine of central nervous system may reduce the posibility of occurence of extrapyramidal side effects, and its therapeutic effects may be extended to negative symptoms and emotional symptoms of schizophrenia. The compound [formula (II)] is a new generation of psychotropic relative to Risperidone. U.S. Food and Drug Administration approved the marketing of an oral sustained release formulation of the compound [formula (II)] (Invega) developed by JANSSEN Pharmaceuticals, Inc in December 2006 for the treatment of mental disorders. Since the hydroxyl group of the compound results in an increased hydrophilicity, the absorption rate via oral administration is reduced, and the absolute bioavailability of the compound is only 28%, which is far lower than that of Risperidone (at least 70%), so that the daily dosage of the compound increased significantly, which in turn lead to increase in the pre-system side effects of the possible unabsorbed drug. The long-chain fatty acid ester of the compound [formula (II)] was reported in W099/25354, but it is metabolized very slowly to form the compound [formula (II)] in vivo and cannot rapidly achieve the effective therapeutic effects. In order to overcome the above drawbacks associated with the compound [formula (II)] and fatty acid esters thereof, a series of derivatives of the compound [formula (II)] (the compounds of formula (I)) were synthesized, used as prodrugs of the compound [formula (II)] and reduced by rapid metabolism in vivo to form the compound [formula (II)] upon being taken, thereby achieving therapeutic effects. CONTENTS OF THE INVENTION The object of the present invention is to develop a new compound, which is a prodrug for the treatment of mental disorders. The below compounds of formula (I) obtained thus by the inventors have an advantage of being rapidly metabolized in vivo to form the compound [formula (II)], thereby having an increased bioavailability and reduced pre-system side effects caused by the possible unabsorbed drug, facilitating the regulation of dosage and therapeutic effects, reducing side effects and the risk of interaction with other drugs. The present invention relates to a compound represented by formula (I), an optical isomer or a pharmaceutically acceptable salt thereof, which is a prodrug for the treatment of mental disorders, wherein, the chiral center () can be R or S or RS (racemic mixture); R is an aryl having 7-20 carbon atoms; or a saturated alkoxy having 1-20 carbon atoms or an unsaturated alkoxy having 2-20 carbon atoms or a cycloalkoxy having 4-20 carbon atoms or an arylalkoxy having 7-20 carbon atoms; or an amino of the following formula having 1-20 carbon atoms: wherein R2 and R3 independently are hydrogen, a saturated alkyl having 1-10 carbon atoms or a non-saturated alkyl having 2-10 carbon atoms or an aryl having 7-10 carbon atoms. R is an aryl having 7-20 carbon atoms, preferably, but not limited to: wherein, R4 and R5 independently are hydrogen, a saturated alkyl or alkoxy having 1-6 carbon atoms, an unsaturated alkyl or alkoxy having 2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably but not limited to hydrogen, methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl. R is a saturated alkoxy having 1-20 carbon atoms or an unsaturated alkoxy having 2-20 carbon atoms or a cycloalkoxy having 4-20 carbon atoms, preferably but not limited to methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy, tert-butoxy, pentoxy, cyclohexyloxy; or an arylalkoxy having 7-20 carbon atoms, preferably but not limited to: wherein , R6 and R7 independently are hydrogen, a saturated alkyl or alkoxy having 1-6 carbon atoms, an unsaturated alkyl or alkoxy having 2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably but not limited to hydrogesn, methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl. R is an amino of the following formula having 1-20 carbon atoms: wherein R2 and R3 independently are hydrogen, a saturated alkyl having 1-10 carbon atoms or a non-saturated alkyl having 2-10 carbon atoms, preferably but not limited to methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl; or an aryl having 7-10 carbon atoms, preferably but not limited to: wherein , R4, R5 independently are hydrogen, a saturated alkyl or alkoxy having 1-6 carbon atoms, an unsaturated alkyl or alkoxy having 2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably but not limited to hydrogen, methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl. According to the present invention, the term "optical isomer" represents an R- or S-optical isomer or an RS-racemic mixtue of a compound of formula (I) or a pharmaceutically acceptable salt thereof. According to the present invention, the representative compounds of formula (I) include: 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylbenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxybenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxybenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorobenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorobenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorobenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-carboxybenzoate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl methyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl propyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}--2-methyl-4-oxo -6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopropyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl butyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl tert-butyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbutyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-pentyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-pentyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopentyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl neopentyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl hexyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl cyclohexyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylphenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylphenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylphenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxyphenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxyphenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxyphenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorophenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorophenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorophenyl carbonate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-dimethylcarbamate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-diethylcarbamate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-dipropylcarbamate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-diisopropylcarbamate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-dibutylcarbamate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-diisobutylcarbamate 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-di-tert-butyl-carbamate and various salts and optical isomers thereof. According to the conventional methods for preparing pharmaceutical formulations in the art, the compound of formula (I) of the present invention, including optical isomers and racemic mixtures and pharmaceutically acceptable salts thereof, can be formulated into suitable dosage forms for oral, injection, transdermal, intranasal, mucosal administration and by inhalation and the like. The dosage forms suitable for oral administration can be either solid tablets, capsules, soft capsules or drop pills, or solutions, suspensions, emulsions or powders, and can be conventional dosage forms, sustained release dosage forms, site specific delivery dosage forms, fast release dosage forms or orally disintegrating dosage forms. The injection administration can be intravenous injection, hypodermical injection, intramuscular injection or intraperitoneal inejction, and the suitable dosage forms therefor can be either solutions, suspensions or emulsions, or conventional or long acting dosage forms such as implants, microspheres or gels. The dosage forms suitable for transdermal administration can be transdermal patches, gels or other dosage forms for transdermal administration. The dosage forms suitable for nasal administration and by inhalation can be solutions, suspensions, emulsions or powders. The dosage forms suitable for mucosal administration can be solutions, suspensions, emulsions, powders or suppositories. The present invention further relates to a pharmaceutical composition comprising an effective amount of a compound of formula (I) and a compatible and pharmaceutically acceptable carrier or diluent. The carrier can be any inert organic or inorganic substances, such as water, gelatin, cellulose, starch, biodegradable polymeric adjuvants such as polyesters or polycarbonates or copolymers of any two or three components thereof, other pharmaceutically active substances, as well as conventional additives such as stabilizers, wetting agents, emulsifiers, flavoring agents and buffers. The compound of formula (I) of the present invention, including optical isomers, racemic mixtures and pharmaceutically acceptable salts thereof, as antagonists of neurotransmitters, can be used for the treatment of mental disorders such as schizophrenia, and the daily dosage thereof can be 0.01-100 mg which can be administrated by single or multiple doses. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows the absorption and metabolism of the compound [formula (II)] and its prodrugs-compounds 1, 2, 3, 5, 6, 7 and compound 8 in Beagles: A. concentration changes of the active metabolite compound of formula (II) the compounds 1, 2 and 3 (ig) and the compound [formula (II)] (iv) in blood; B. concentration changes of the active metabolite compound of formula (II) of the compounds 5, 6, 7 and 8 (ig) and the compound [formula (II)] (iv) in blood; C. measurements of the concentrations of prototype compounds 1,2, 3, 5, 6, 7 and 8 for the compounds 1,2,3, 5, 6, 7 and 8 ( ig) in blood. CONCRETE MODELS FOR CARRYING OUT THE INVENTION The present invention is further illustrated by the following examples, without being construded to restrict the scope of the invention in any way. A. Synthesis of the compound [formula (II)] 1. Preparation of 3-(2-chloroethyl)-2-methyl-9-benzyloxy-6,7,8,9- tetrahydropyrido[1,2-a]pyrimidin-4-one Toluene 1500ml, 2-amino-3-benzyloxy-pyridine 120g (0.65mole), 2-acetyl Y-butyrolactone 114ml (1.05mole) were added to a reaction bottle, and phosphorus oxychloride 300ml (3.21 mole) was added dropwise. The reaction was conducted at 90-93°C for 5 hours. The soluvent was distilled out at a reduced pressure, the residue was poured into brash ice, adjusted to a pH 9 with 25% ammonia, extracted with chloroform for three times (100ml per time), washed with water, dried over anhydrous magnesium sulfate. The solvent was distilled out at a reduced pressure, the residue while hot was dissolved in 100ml isopropanol, and stood overnight. The precipitated crystal was filtered out, washed with isopropanol, and dried to obtain 65.0g of light pink crystal (yield 31%). Mp: 139.9-140.9°C. 2. Preparation of 3-(2-chloroethyl)-2-methyl-9-hydroxy-6,7,8,9-tetrahydro- pyrido[1,2-a]pyrimidin-4-one At room temperature, 3-(2-chloroethyl)-2-methyl-9-benzyloxy-6,7,8,9- tetrahydro-pyrido[1,2-a]pyrimidin-4-one 4.0g (0.0122mole) was charged into a 250 mL three-necked bottle, 80 mL methanol was added, and then concentrated hydrochloric acid (about 25 drops) was added dropwise with stirring to adjust pH to 3.0. After the dissolution was completed, 1.8g of wet 5% Pd-C (water content: 56%) (W/W: 10/1) was added, argon gas was fed to exchange atmosphere for three times, hydrogen gas was fed to exchange atmosphere for three times, the reaction was conducted at 27°C for about 36 hours, and TLC (ethyl ether : n-hexane : methanol : triethylamine = 2mL : 0.5mL : 6 drops : 6 drops) was used to detect the debenzylated product. The reaction was stopped after all starting materials were consumed. A light green liquid was obtained by sucking filtration, and distilled at a reduced pressure to remove solvent to obtain a dark green viscous liquid. About 16mL distilled water was added, dissolution was conducted under ultrasound, the temperature was decreased to 5°C by using an icewater bath, and the pH was adjusted to 10-11 by adding 2N aqueous sodium hydroxide so as to precipitate a large amount of white solid when the pH was close to its end. The white solid was filtered out at a reduced pressure. The filtrate was extracted with 2x20mL of dichloromethane. The organic layers were combined and washed with saturated aqueous NaCI solution for twice (10mL per time), dried over anhydrous magnesium sulfate. Light yellow solids were obtained after the solvent was distilled out. The resulting solids were combined and dried to obain 2.14g product (yield: 72.6%). Mp: 100.8-102.7°C. 3. Preparation of 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]- ethyl}-2-methyl-9-hydroxy-6,7,8,9-tetrahydropyrido[1,2-a]pyrimidin-4-one (the compound [formula (II)]) Methanol 100ml, 6-fluoro-3-piperidin-4-yl-1,2-benzoisoxazole hydrochloride 10.27g (0.04mole), 3-(2-chloroethyl)-2-methyl-9-benzyloxy-6,7,8,9-tetrahydro- pyrido[1,2-a]pyrimidin-4-one 9.17g (0.04mole), diisopropylamine 10ml were added to a reaction bottle and reacted at 60°C for 14 hours. The solvent was distilled out at a reduced pressure, water and chloroform (q.s.) were added, the pH was adjusted to 8 with 10% NaOH, the obtained chloroform extract was washed with water for three times, and dried over anhydrous magnesium sulfate. The solvent was distilled out at a reduced pressure to obtain a viscous product at which time 100mL isopropanol was added to make it disolve, and stood overnight. The precipitated crystal was filtered out to obtain a crude product 9.0g. Colum chromatography refinement: a colum chromatography on silica gel using chlorform-methanol (100:2) as eluant was conducted to obtain the refined product, the compound [formula (II)] 5.6g (yield: 32.8%), mp: 174.7-178.3°C. B. Synthesis of aromatic carboxylic acid esters of the compound [formula (II)] General methods and processes Reaction scheme: wherein X is an aryl having 7-20 carbon atoms, such as phenyl, tolyl, methoxyphenyl, etc. To 10mL anhydrous pyridine, the compound [formula (II)] 0.43g (1 mmol) was added, dissolved under stirring at room temperature, an aromatic acid chloride (2mmol) was added dropwise, and the reaction is conducted until starting materials spots disappeared on TLC. The reaction was poured into water, adjusted to a pH of 9 with 10% aqueous NaOH, and extracted with chloroform for three times (15mL per time). The extract was washed with water, and dried over anhydrous magnesium sulfate. The solvent was distilled out at a reduced pressure to obtain a product. The product was dissolved in 2mL anhydrous ethanol, and 3mL of saturated anhydrous ethanol-HCI solution was added dropwise, and the mixture was standed overnight. The precipitated solid was filtered out, washed with ethyl acetate, dried to obain 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl aromatic carboxylate hydrochloride. The following compounds were synthesized and characterized according to the above reaction scheme. Example 1: Synthesis of aromatic carboxylic acid esters (formula (III)) of the compound [formula (II)] 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate is given below as example. To 10mL anhydrous pyridine, the compound [formula (II)] 0.43g (1 mmol) was added, dissolved under stirring at room temperature, benzoyl chloride 0.28g (2mmo!) was added dropwise, and the reaction was conducted until starting materials spots disappeared on TLC. The reaction was poured into water, adjusted to a pH of 9 with 10% NaOH, and extracted with chloroform for three times (15mL per time). The extract was washed with water, and dried over anhydrous magnesium sulfate. The solvent was distilled out to obtain a product. The product was dissolved in 2mL anhydrous ethanol, 3mL of saturated anhydrous ethanol-HCI solution was added dropwise, and the mixture was standed overnight. The precipitated solid was filtered out, washed with ethyl acetate, dried to obain 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]- ethyl}-2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate dihydrochloride 0.33 g. The product was convereted to obtain 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-piperidin-1-yl]ethyl}-2-methyl-4-oxo-6,7, 8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate 0.30 g. Melting point is The following compounds were synthesized and characterized according to this method. Compound 1. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]- ethyl}-2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate 1H-NMR(CDCI3):2.10-2.27(8H,rn,-CH2-), 2.29(3H,s,-CH3), 2.58, 2.78, 3.18(6H,t,t,t,>N-CH2-), 3.91, 4.11(2H,m,m,-CON-CH2-), 3.10(1H,m,- >-CH-), 6.02(1 H,t,=-CH-0-), 7.02-8.06 (8H,m,Ar-H ). 13CNMR: 20.61, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C), 50.74, 79.57, 99.70, 107.36, 114.31, 118.63, 126.83, 129.07(2C), 130.09(2C), 130.97, 133.02, 141.91, 143.75, 155.11, 157.00, 163.78, 165.58, 166.57. Compound 2. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate The reaction conditions were substantively the same, except that benzoylchloride was replaced with 4-methylbenzoylchloride to obtain 0.36g of 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate. Mp: 112.1-113.5°C. 1H-NMR(CDCI3): 2.04-2.34(8H,m,-CH2-), 2.40(6H,s,-CH3), 2.56,2.80,2.91 (6H,t,t,t,>N-CH2-), 3.22(1H,m,-N=-CH-), 3.91,4.11 (2H,m,m, -CON-CH2-), 5.96 (1H,t,=-CH-O-), 6.98-7.99 (7H,m,Ar-H ). 13C-NMR 20.61, 21.40, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C), 50.74, 79.57, 99.70, 107.36, 114.35, 118.63, 125.84, 126.43, 127.21(2C), 129.23(2C), 141.90, 141.91, 143.75, 155.11, 157.00, 163.78, 165.58, 166.57. Compound 3. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate The reaction conditions were substantively the same, except that 4-methylbenzoylchloride was replaced with 4-methoxybenzoylchloride to obtain 0.26g 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-2-methyl- 4-0X0-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate, mp. 96.1-98.0°C. 1H-NMR(CDCI3): 2.08-2.22(6H,m,-CH2-), 2.28(3H,s,-CH3), 2.39(2H,t,-CH2-), 2.65,2.8213.27(6H,t1t,t,>N-CH2-), 3.14(1H,m,-N =-CH-), 3.83(3H,s,-OCH3), 3.89, 4.10 (2H,m,m, -CON-CH2-), 5.93(1 H,t,=-CH-O-), 6.91-8.10 (7H,m,Ar-H ). 13C-NMR: 20.61, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C), 50.74, 55.25, 79.57, 99.70, 107.36, 114.24(2C), 114.35, 118.63, 121.80, 125.84, 130.82(2C), 141.91, 143.75, 155.11, 157.00, 162.50, 163.78, 165.58, 166.57, Compound 4. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorobenzoate The reaction conditions were substantively the same, except that 4-methylbenzoylchloride was replaced with 4-fluorobenzoylchloride. 1HNMR: d 1.94-2.12(6H m-CH2-), 2.19 (3H s CH3), 2.20-2.30(4H t-NCH2-), 2.48(2H t-CH2-),2.54(2H t-CH2N-), 2.58(1 H m >CH-), 2.61-2.76(2H m-CH2-),3.43-3.55(2H t-CH2N-), 5.85(1H t >CHOC(C=O)-), 6.61(1H m Ar-H), 7.17-8.03(6H m Ar-H). 13C-NMR: 20.61, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C), 50.74, 79.57, 99.70, 107.36, 114.31, 115.86(2C), 118.63, 125.84, 126.36, 130.25(2C), 141.91, 143.75, 155.11, 157.00, 163.87, 164.88, 165.58, 166.57. Melting point: 226.1 -227.6°C (hydrochloride). Example 2: Synthesis of carbonyl carboxylic acid esters (formula (IV)) of the compound [formula (II)] A. General methods and processes Reaction scheme: wherein Y is a saturated alkyl having 1-20 carbon atoms or an unsaturated alkyl having 2-20 carbon atoms or a cycloalkyi having 4-20 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and various isomers thereof, cyclohexyl, etc.; or an aryl having 7-20 carbon atoms, such as phenyl, tolyl, methoxyphenyl, etc. Compound 5. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate hydrochloride To 30ml anhydrous dichloromethane and 3ml anhydrous pyridine, 2.0g (4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at room temperature, then 1.0g (9.38mmol) ethyl chloroformate was added dropwise, and reacted until starting materials spots disappeared on TLC. The reaction was poured into a sufficient amount of water, adjusted to pH of 9 with 10% aqueous NaOH solution, and extracted with dichloromethane for three times (30ml per time). The extract was washed with water, dried over anhydrous magnesium sulfate, and distilled at a reduced pressure to remove solvent. The residue was dissoved in 5ml anhydrous ethanol, and then 5ml of saturated anhydrous ethanol-HCI solution was added dropwise. After standing overnight, the precipitated solid was filtered out, washed with ethyl acetate, and dried to obtain 1.60g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4- oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate hydrochloride, mp.: 229.0-229.5°C. 1H-NMR(CDCI3): 1.32(3H,t,-CH3), 2.02-2.60(8H,m,-CH2-), 2.39(3H,s,Ar-CH3), 2.40-3.47(6H,m, >N-CH2-), 3.22(1 H,m,-N=-CH-), 3.91,4.11(2H,m,m,-CON-CH2-), 4.23(2H,m,-OCH2-), 5.96(1 H,t,=-CH-O-), 7.01-7.22(3H,m,Ar-H ). 13CNMR: 13.93, 20.61, 22.90, 24.02, 27.69(2C), 32.10, 34.27, 42.65, 48.73(2C), 50.74, 62.40, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 126.83, 148.20, 150.05, 155.11, 163.78, 165.08, 166.57. Compound 6. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate dihydrochloride To 30ml anhydrous dichloromethane and 3ml anhydrous pyridine, 2.0g (4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at room temperature, then 1.29g (9.38mmol) isobutyl chloroformate was added dropwise, and reacted until starting materials spots disappeared on TLC. The reaction was poured into a sufficient amount of water, adjusted to pH of 9 with 10% aqueous NaOH solution, and extracted with dichloromethane for three times (30ml per time). The extracts were washed with water, dried over anhydrous magnesium sulfate, and distilled at a reduced pressure to remove solvent. The residue was dissoved in 5ml anhydrous ethanol, and then 5ml of saturated anhydrous ethanol-HCI solution was added dropwise. After standing overnight, the precipitated solid was filtered out, washed with ethyl acetate, and dried to obtain 1.65g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2- methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate dihydrochloride, mp.: 242.1-243.5°C. 1H-NMR(DMSO-d6): 0.88(6H,d,-CH-), 2.25(3H,s, Ar-CH3), 2.99- 3.12 (6H,m, >N-CH2-), 3.50(1H,m,-N=-CH-), 3.70,3.97 (6H,m,m, -CON-CH2-, -OCH2-,Ar-CH2-), 5.55(1 H,t, =-CH-O-), 6.56(1 H.br.HCI), 7.31-8.18 (3H,m,Ar-H ), 11.02(1H,br,HCI). 13CNMR: 19.12(2C), 20.61, 22.90, 24.02, 27.83, 27.69(2C), 32.10, 34.27, 42.65, 48.73(2C), 50.74, 70.66,81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 126.83, 148.20, 150.05, 155.11, 163.78, 165.08, 166.57. Compound 7. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate dihydrochloride To 30ml anhydrous dichloromethane and 3ml anhydrous pyridine, 2.0g (4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at room temperature, then 1.42g (9.38mmol) pentyl chloroformate was added dropwise, and reacted until starting materials spots disappeared on TLC. The reaction was poured into a sufficient amount of water, adjusted to pH of 9 with 10% aqueous NaOH solution, and extracted with dichloromethane for three times (30ml per time). The extracts were washed with water, dried over anhydrous magnesium sulfate, and distilled at a reduced pressure to remove solvent. The residue was dissoved in 5ml anhydrous ethanol, and then 5ml of saturated anhydrous ethanol-HCI solution was added dropwise. After standing overnight, the precipitated solid was filtered out, washed with ethyl acetate, and dried to obtain 1.72g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2- methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate dihydrochloride, mp.: 232.5-233.6°C. 1H-NMR(DMSO-d6): 0.86(3H,d,-CH3), 1.30-1.61 (8H,m,-CH2-), 1.97-2.48(8H,m,-CH2-), 2.32(3H,s, Ar-CH3), 2.99-3.71 (6H,m, >N-CH2-), 3.71(3H,m,- N =-CH-, Ar-CH2-), 3.50,3.90 (6H,m,m,-CON-CH2-),4.16 (2H,m,-OCH2-),), 5.55(1H, t,=-CH-O-),7.32-8.25(3H,m,Ar-H ),8.46(1H,br, HCI),11.26 (1H,br, HCI). 13CNMR:13.99, 20.61, 22.42, 22.90, 24.02, 27.69(2C), 28.23, 28.48, 32.10, 34.27, 42.65, 48.73(2C), 50.74, 64.64, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 126.83, 148.20, 150.05, 155.11, 163.78, 165.08, 166.57. Compound 8. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyljethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate hydrochloride To 10ml anhydrous dichloromethane and 1ml anhydrous pyridine, 2.0g (4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at room temperature, then 1.48g (9.38mmol) phenyl chloroformate was added dropwise, and reacted until starting materials spots disappeared on TLC. The reaction was extracted with dichloromethane for three times (15ml per time). The extracts were washed with water, dried over anhydrous magnesium sulfate, and distilled at a reduced pressure to remove solvent. The residue was dissoved in 2ml anhydrous ethanol, and then 3ml of anhydrous ethanol-HCI saturated solution was added dropwise. After standing overnight, the precipitated solid was filtered out, washed with ethyl acetate, and dried to obtain 1.51 g of 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate hydrochloride. Mp.: 186.7-187.8°C. 1H-NMR(CDCI3): 2.03-2.60(8H,m,-CH2-), 2.43(3H,s,Ar-CH3), 3.07,3.11(6H,m,>N-CH2-), 3.46(1H, m,-N =-CH-),3.88, 3.98(2H,m,-CON-CH2-), 5.65(1 H,t,=-CH-O-), 6.78-7.40 (8H,m,Ar-H ), 7.95 (1H,br, HCI). 13CNMR: 20.61, 22.90, 24.02, 27.69(2C), 32.10, 34.27, 42.65, 48.73(2C), 50.74, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 121.48(2C), 125.60, 127.92, 130.09(2C), 142.58, 150.05, 150.35, 155.11, 163.78, 165.08, 166.57. Melting point: 249.2-251.5°C. Compound 9. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}- 2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl p-nitrophenyl carbonate hydrochloride To 10ml anhydrous dichloromethane and 1ml anhydrous pyridine, 2.0g (4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at room temperature, then 1.91g (9.38mmol) p-nitrophenyl chloroformate was added dropwise, and reacted until starting materials spots disappeared on TLC. The reaction was extracted with dichloromethane for three times (15ml per time). The extracts were washed with water, dried over anhydrous magnesium sulfate, and distilled at a reduced pressure to remove solvent. The residue was dissoved in 2ml anhydrous ethanol, then 3ml of anhydrous ethanol-HCI saturated solution was added dropwise. After standing overnight, the precipitated solid was filtered out, washed with ethyl acetate, and dried to obtain 1.69g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-6,7,8,9-tetrahydro-pyr ido[1,2-a]pyrimidin-9-yl p-nitrophenyl carbonate hydrochloride. 1H-NMR(CDCI3): 1.78-2.47(8H,m,-CH2-), 2.35(3H,s,Ar-CH3), 2.60,2.95,3.36 (6H,m,>N-CH2-), 3.28(1H, m,- N° =-CH-), 3.83(1H,s,HCI), 3.95,4.03 (2H,m, -CON-CH2-), 5.58(1 H,t,=-CH-O-), 6.93-8.10(8H,m,Ar-H ),7.95 (1H,br,HCI). 13CNMR: 20.61, 22.90, 24.02, 27.69(2C), 32.10, 34.27, 42.65, 48.73(2C), 50.74, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 122.18(2C), 125.18(2C), 127.92, 145.38, 148.20, 150.05, 155.11,155.47, 163.78, 165.08, 166.57. Example 3: Tests of the compounds being metabolized to form the active component, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-9- hydroxy-2-methyl-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one, (the compound [formula (II)]) in liver cells 40 µg of the Compound 1 of Example 1 (or Compound 2 or Compound 3 or Compound 5 or Compound 6 or Compound 7 or Compound 8 or Compound 9) was dissolved in 0.01 M potassium phosphate buffer solution (containing 1mM NADPH), mixed with 25 uL of human liver cells S9 (20mg protein/mL, H961), cultured at 37°C for 2 hours, and then the mixture was quenched with concentrated perchloric acid. After the precipitated proteins were removed by centrifugation, the obtained supernatant solution was adjusted to pH of 3 with concentrated potassium phosphate solution, and centrifuged again. The obtained supernatant was directly injected into HPLC for analysis. The metabolism results were shown in Table 1. The metabolic rates of the compounds being metabolized in liver cells for 2 hours to form the active component 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-9- hydroxy-2-methyl-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one (the compound [formula (II)]) ranged from 70% to 95%, depending on the different ester groups. Example 4: Measurement of the absolute bioavailability - Beagle tests of the compound [formula (II)] and its prodrugs, the compounds 1, 2, 3, 5, 6, 7 and 8 Twenty one beagles weighing about 10kg were divided into 7 groups, and intragastrically administered the compounds 1, 2, 3, 5, 6, 7 and 8 at a dosage of 9.4 µmol/beagle, respectively. Blood samples were taken at the predetermined time points, and the concentrations of the active metabolite (the compound [formula (II)]) and prodrugs in blood were measured. In the meantime, three beagles weighing about 10kg were intravenously administered with the compound [formula (II)] at a dosage equimolar to the prodrug, as the control group, and the concentrations of the compound [formula (II)] in blood were measured. The results were shown in Fig.1 and Table 2. The prodrugs were immediately metabolized almost completely to form the active metabolite in beagle body, the compound [formula (II)] upon being administrated parenterally, and the concentrations of the original compounds were very low (see: Fig.lC). The results also indicateed that the bioavailability of the prodrugs of the compound [formula (II)] were significantly higher than that of Invega (28%). Particularity, the prodrugs of carbonate type had a very remarkable improvement of bioavailability. Example 6: Preparation of oral conventional tablets Tablets were obtained by direct tabletting, and each tablet contained 6mg of active ingredient (expressed in the compound [formula (II)]). The oral conventional tablets were subjected to dissolution tests, and the results were shown in table 3 below. Granules were obtained by using conventional fluidized bed. After the coating was dried, the coated granules were filled into hard gelatin capsules, each capcule contain 6mg of the active ingredient (expressed in the compound [formula (II)]), and the coating degree was 6%. The capsules were subjected to dissolution tests according the method specified in the Pharmacopoeia of the People's Republic of China. The results were shown in table 4 below. What is claimed is: 1. A compound of formula (I), wherein , the chiral center () can be R or S or RS (racemic mixture); R is an aryl having 7-20 carbon atoms; or a saturated alkoxy having 1-20 carbon atoms or an unsaturated alkoxy having 2-20 carbon atoms or a cycloalkoxy having 4-20 carbon atoms or an arylalkoxy having 7-20 carbon atoms; or an optical isomer thereof or a pharmaceutically salt thereof. 2. The compound of formula (I) according to claim 1, characterized in that, in the compound of formula (I), R is an aryl having 7-20 carbon atoms, preferably wherein, R4 and R5 independently are hydrogen, a saturated alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms, an unsaturated alkyl having 2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably hydrogen, methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl. 3. The compound of formula (I) according to claim 1, characterized in that, in the compound of formula (I), R is a saturated alkoxy having 1-20 carbon atoms or an unsaturated alkoxy having 2-20 carbon atoms or a cycloalkoxy having 4-20 carbon atoms, preferably, R is a saturated alkoxy having 1-10 carbon atoms or an unsaturated alkoxy having 2-10 carbon atoms or a cycloalkoxy having 4-10 carbon atoms; or an arylalkoxy having 7-20 carbon atoms, preferably: wherein , R6 and R7 independently are hydrogen, a saturated alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms, an unsaturated alkyl having 2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably hydrogen, methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl. 4. A salt of the compound of formula (I) according to claim 1, characterized in that the salt of the compound is hydrochloride, sulfate, maleate, succinate, and other salts formed with a pharmaceutically acceptable acid. 5. The compound according to any one of claims 1-5, wherein the compound is selected from the group consisting of: 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylbenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxybenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxybenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorobenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorobenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorobenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-carboxybenzoate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl methyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl propyl carbonate, 3.{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}--2-methyl-4-oxo -6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopropyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl butyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl tert-butyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbutyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-pentyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-pentyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazoi-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopentyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl neopentyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl hexyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl cyclohexyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylphenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylphenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylphenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxyphenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxyphenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxyphenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorophenyl carbonate, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorophenyl carbonate, and 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo- 6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorophenyl carbonate, and various salts and optical isomers thereof. 6. A pharmaceutical composition comprising a compound according to any one of claims 1-5 or an optical isomer or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. 7. Use of a compound according to any one of claims 1-5, or an optical isomer or pharmaceutically acceptable salt thereof in the manufacture of a medicament as antagonist of neurotransmitters for the treatment of the related mental disorders, such as schizophrenia. 8. The pharmaceutical composition according to claim 6, wherein the composition is administrated by oral, injection, transdermal, intranasal, or mucosal mode or by inhalation administration. 9. The pharmaceutical composition according to claim 8, wherein the composition is presented in conventional, sustained-release, controled-release, site specific delivery or fast release dosage form, preferably oral sustained-release dosage form, reservoir-type injection such as sustained-release microspheres, implants. The present invention relates to a compound of formula (I), an optical isomer or a pharmaceutically acceptable salt thereof, its preparation and uses, wherein R is defined as herein. Such compounds can be presented as an optical isomer or a racemic mixture. The compounds can be metabolized in vivo to form a pharmacologically active substance as antagonist of neurotransmitters, and can be used for the treatment of the related mental disorders such as schizophrenia.

Full Text

NOVEL COMPOUNDS FOR TREATING MENTAL DISORDERS.
AND PREPARATION AND USES THEREOF
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a compound of formula (I) and salts thereof,
a process for preparing the same, a pharmaceutical composition comprising the
same, and their use for the treatment or auxiliary treatment of mental disorders.

BACKGROUND OF THE INVENTION
It has been reported that the compound [formula (II)]
[3-{2-[4-(6-fluoro-benzo[d]isoxazol-3-yl)piperidin-1-yl]-ethyl}-9-hydroxy-2-methyl-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one; or IUPAC name:
3-[2-[4-(6-fluorobenzo[d]isoxazol-3-yl)-1-piperidyl]ethyl]-7-hydroxy-4-methyl-1,5-
diazabicyclo[4.4.0]deca-3,5-dien-2-one; CAS Nr. 144598-75-4; MW 426.48;
Paliperidone or 9-OH risperidone or 9-hydroxy risperidone] is a benzoisoxazole
derivative and one of new generation antipsychotics. The compound [formula (II)]
is a selective monoaminergic antagonist having unique properties, and has a high
affinity to serotoninergic 5-HT2 receptor and dopamine D2 receptor. The
compound [formula (II)] can also binds to a1-adrenergic receptor, and binds to
histaminergic H1 receptor and a2-adrenoceptor with a relatively low affinity. The
compound [formula (II)] does not bind to a cholinergic receptor. The compound
[formula (II)] is a potent D2 antagonist and can improve positive symptoms of
schizophrenia, but it may cause less motor function inhibition and catalepsy than
classic antipsychotics. Its balanced antagonistic effects on serotonin and
dopamine of central nervous system may reduce the posibility of occurence of
extrapyramidal side effects, and its therapeutic effects may be extended to
negative symptoms and emotional symptoms of schizophrenia.
The compound [formula (II)] is a new generation of psychotropic relative to
Risperidone. U.S. Food and Drug Administration approved the marketing of an
oral sustained release formulation of the compound [formula (II)] (Invega)
developed by JANSSEN Pharmaceuticals, Inc in December 2006 for the
treatment of mental disorders. Since the hydroxyl group of the compound results
in an increased hydrophilicity, the absorption rate via oral administration is
reduced, and the absolute bioavailability of the compound is only 28%, which is
far lower than that of Risperidone (at least 70%), so that the daily dosage of the
compound increased significantly, which in turn lead to increase in the pre-system
side effects of the possible unabsorbed drug. The long-chain fatty acid ester of
the compound [formula (II)] was reported in W099/25354, but it is metabolized
very slowly to form the compound [formula (II)] in vivo and cannot rapidly achieve
the effective therapeutic effects. In order to overcome the above drawbacks
associated with the compound [formula (II)] and fatty acid esters thereof, a series
of derivatives of the compound [formula (II)] (the compounds of formula (I)) were
synthesized, used as prodrugs of the compound [formula (II)] and reduced by
rapid metabolism in vivo to form the compound [formula (II)] upon being taken,
thereby achieving therapeutic effects.

CONTENTS OF THE INVENTION
The object of the present invention is to develop a new compound, which is a
prodrug for the treatment of mental disorders. The below compounds of formula (I)
obtained thus by the inventors have an advantage of being rapidly metabolized in
vivo to form the compound [formula (II)], thereby having an increased
bioavailability and reduced pre-system side effects caused by the possible
unabsorbed drug, facilitating the regulation of dosage and therapeutic effects,
reducing side effects and the risk of interaction with other drugs.
The present invention relates to a compound represented by formula (I), an
optical isomer or a pharmaceutically acceptable salt thereof, which is a prodrug
for the treatment of mental disorders,

wherein,
the chiral center (*) can be R or S or RS (racemic mixture);
R is an aryl having 7-20 carbon atoms; or a saturated alkoxy having 1-20
carbon atoms or an unsaturated alkoxy having 2-20 carbon atoms or a
cycloalkoxy having 4-20 carbon atoms or an arylalkoxy having 7-20 carbon atoms;
or an amino of the following formula having 1-20 carbon atoms:

wherein R2 and R3 independently are hydrogen, a saturated alkyl having
1-10 carbon atoms or a non-saturated alkyl having 2-10 carbon atoms or an aryl
having 7-10 carbon atoms.
R is an aryl having 7-20 carbon atoms, preferably, but not limited to:

wherein, R4 and R5 independently are hydrogen, a saturated alkyl or alkoxy
having 1-6 carbon atoms, an unsaturated alkyl or alkoxy having 2-6 carbon atoms,
OH, CI, F, CN, carboxyl and ester group; preferably but not limited to hydrogen,
methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl.
R is a saturated alkoxy having 1-20 carbon atoms or an unsaturated alkoxy
having 2-20 carbon atoms or a cycloalkoxy having 4-20 carbon atoms, preferably
but not limited to methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy,
tert-butoxy, pentoxy, cyclohexyloxy; or an arylalkoxy having 7-20 carbon atoms,
preferably but not limited to:

wherein , R6 and R7 independently are hydrogen, a saturated alkyl or alkoxy
having 1-6 carbon atoms, an unsaturated alkyl or alkoxy having 2-6 carbon atoms,
OH, CI, F, CN, carboxyl and ester group; preferably but not limited to hydrogesn,
methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl.
R is an amino of the following formula having 1-20 carbon atoms:

wherein R2 and R3 independently are hydrogen, a saturated alkyl having
1-10 carbon atoms or a non-saturated alkyl having 2-10 carbon atoms, preferably
but not limited to methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl; or an
aryl having 7-10 carbon atoms, preferably but not limited to:

wherein , R4, R5 independently are hydrogen, a saturated alkyl or alkoxy
having 1-6 carbon atoms, an unsaturated alkyl or alkoxy having 2-6 carbon atoms,
OH, CI, F, CN, carboxyl and ester group; preferably but not limited to hydrogen,
methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl.
According to the present invention, the term "optical isomer" represents an R-
or S-optical isomer or an RS-racemic mixtue of a compound of formula (I) or a
pharmaceutically acceptable salt thereof.
According to the present invention, the representative compounds of formula
(I) include:
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylbenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxybenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxybenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorobenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorobenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorobenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-carboxybenzoate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl methyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl propyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}--2-methyl-4-oxo
-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopropyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl butyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl tert-butyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbutyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-pentyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-pentyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopentyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl neopentyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl hexyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl cyclohexyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylphenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylphenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylphenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxyphenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxyphenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxyphenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorophenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorophenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorophenyl carbonate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-dimethylcarbamate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-diethylcarbamate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-dipropylcarbamate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-diisopropylcarbamate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-dibutylcarbamate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-diisobutylcarbamate
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl N,N-di-tert-butyl-carbamate
and various salts and optical isomers thereof.
According to the conventional methods for preparing pharmaceutical
formulations in the art, the compound of formula (I) of the present invention,
including optical isomers and racemic mixtures and pharmaceutically acceptable
salts thereof, can be formulated into suitable dosage forms for oral, injection,
transdermal, intranasal, mucosal administration and by inhalation and the like.
The dosage forms suitable for oral administration can be either solid tablets,
capsules, soft capsules or drop pills, or solutions, suspensions, emulsions or
powders, and can be conventional dosage forms, sustained release dosage forms,
site specific delivery dosage forms, fast release dosage forms or orally
disintegrating dosage forms. The injection administration can be intravenous
injection, hypodermical injection, intramuscular injection or intraperitoneal
inejction, and the suitable dosage forms therefor can be either solutions,
suspensions or emulsions, or conventional or long acting dosage forms such as
implants, microspheres or gels. The dosage forms suitable for transdermal
administration can be transdermal patches, gels or other dosage forms for
transdermal administration. The dosage forms suitable for nasal administration
and by inhalation can be solutions, suspensions, emulsions or powders. The
dosage forms suitable for mucosal administration can be solutions, suspensions,
emulsions, powders or suppositories.
The present invention further relates to a pharmaceutical composition
comprising an effective amount of a compound of formula (I) and a compatible
and pharmaceutically acceptable carrier or diluent. The carrier can be any inert
organic or inorganic substances, such as water, gelatin, cellulose, starch,
biodegradable polymeric adjuvants such as polyesters or polycarbonates or
copolymers of any two or three components thereof, other pharmaceutically
active substances, as well as conventional additives such as stabilizers, wetting
agents, emulsifiers, flavoring agents and buffers.
The compound of formula (I) of the present invention, including optical
isomers, racemic mixtures and pharmaceutically acceptable salts thereof, as
antagonists of neurotransmitters, can be used for the treatment of mental
disorders such as schizophrenia, and the daily dosage thereof can be 0.01-100
mg which can be administrated by single or multiple doses.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows the absorption and metabolism of the compound [formula (II)]
and its prodrugs-compounds 1, 2, 3, 5, 6, 7 and compound 8 in Beagles:
A. concentration changes of the active metabolite compound of formula (II)
the compounds 1, 2 and 3 (ig) and the compound [formula (II)] (iv) in blood;
B. concentration changes of the active metabolite compound of formula (II) of
the compounds 5, 6, 7 and 8 (ig) and the compound [formula (II)] (iv) in blood;
C. measurements of the concentrations of prototype compounds 1,2, 3, 5, 6,
7 and 8 for the compounds 1,2,3, 5, 6, 7 and 8 ( ig) in blood.
CONCRETE MODELS FOR CARRYING OUT THE INVENTION
The present invention is further illustrated by the following examples, without
being construded to restrict the scope of the invention in any way.
A. Synthesis of the compound [formula (II)]
1. Preparation of 3-(2-chloroethyl)-2-methyl-9-benzyloxy-6,7,8,9-
tetrahydropyrido[1,2-a]pyrimidin-4-one
Toluene 1500ml, 2-amino-3-benzyloxy-pyridine 120g (0.65mole), 2-acetyl
Y-butyrolactone 114ml (1.05mole) were added to a reaction bottle, and
phosphorus oxychloride 300ml (3.21 mole) was added dropwise. The reaction was
conducted at 90-93°C for 5 hours. The soluvent was distilled out at a reduced
pressure, the residue was poured into brash ice, adjusted to a pH 9 with 25%
ammonia, extracted with chloroform for three times (100ml per time), washed with
water, dried over anhydrous magnesium sulfate. The solvent was distilled out at a
reduced pressure, the residue while hot was dissolved in 100ml isopropanol, and
stood overnight. The precipitated crystal was filtered out, washed with
isopropanol, and dried to obtain 65.0g of light pink crystal (yield 31%). Mp:
139.9-140.9°C.
2. Preparation of 3-(2-chloroethyl)-2-methyl-9-hydroxy-6,7,8,9-tetrahydro-
pyrido[1,2-a]pyrimidin-4-one
At room temperature, 3-(2-chloroethyl)-2-methyl-9-benzyloxy-6,7,8,9-
tetrahydro-pyrido[1,2-a]pyrimidin-4-one 4.0g (0.0122mole) was charged into a
250 mL three-necked bottle, 80 mL methanol was added, and then concentrated
hydrochloric acid (about 25 drops) was added dropwise with stirring to adjust pH
to 3.0. After the dissolution was completed, 1.8g of wet 5% Pd-C (water content:
56%) (W/W: 10/1) was added, argon gas was fed to exchange atmosphere for
three times, hydrogen gas was fed to exchange atmosphere for three times, the
reaction was conducted at 27°C for about 36 hours, and TLC (ethyl ether :
n-hexane : methanol : triethylamine = 2mL : 0.5mL : 6 drops : 6 drops) was used
to detect the debenzylated product. The reaction was stopped after all starting
materials were consumed.
A light green liquid was obtained by sucking filtration, and distilled at a
reduced pressure to remove solvent to obtain a dark green viscous liquid. About
16mL distilled water was added, dissolution was conducted under ultrasound, the
temperature was decreased to 5°C by using an icewater bath, and the pH was
adjusted to 10-11 by adding 2N aqueous sodium hydroxide so as to precipitate a
large amount of white solid when the pH was close to its end. The white solid was
filtered out at a reduced pressure. The filtrate was extracted with 2x20mL of
dichloromethane. The organic layers were combined and washed with saturated
aqueous NaCI solution for twice (10mL per time), dried over anhydrous
magnesium sulfate. Light yellow solids were obtained after the solvent was
distilled out. The resulting solids were combined and dried to obain 2.14g product
(yield: 72.6%). Mp: 100.8-102.7°C.
3. Preparation of 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]-
ethyl}-2-methyl-9-hydroxy-6,7,8,9-tetrahydropyrido[1,2-a]pyrimidin-4-one (the
compound [formula (II)])
Methanol 100ml, 6-fluoro-3-piperidin-4-yl-1,2-benzoisoxazole hydrochloride
10.27g (0.04mole), 3-(2-chloroethyl)-2-methyl-9-benzyloxy-6,7,8,9-tetrahydro-
pyrido[1,2-a]pyrimidin-4-one 9.17g (0.04mole), diisopropylamine 10ml were
added to a reaction bottle and reacted at 60°C for 14 hours. The solvent was
distilled out at a reduced pressure, water and chloroform (q.s.) were added, the
pH was adjusted to 8 with 10% NaOH, the obtained chloroform extract was
washed with water for three times, and dried over anhydrous magnesium sulfate.
The solvent was distilled out at a reduced pressure to obtain a viscous product at
which time 100mL isopropanol was added to make it disolve, and stood overnight.
The precipitated crystal was filtered out to obtain a crude product 9.0g.
Colum chromatography refinement: a colum chromatography on silica gel
using chlorform-methanol (100:2) as eluant was conducted to obtain the refined
product, the compound [formula (II)] 5.6g (yield: 32.8%), mp: 174.7-178.3°C.
B. Synthesis of aromatic carboxylic acid esters of the compound [formula (II)]
General methods and processes
Reaction scheme:

wherein X is an aryl having 7-20 carbon atoms, such as phenyl, tolyl,
methoxyphenyl, etc.
To 10mL anhydrous pyridine, the compound [formula (II)] 0.43g (1 mmol)
was added, dissolved under stirring at room temperature, an aromatic acid
chloride (2mmol) was added dropwise, and the reaction is conducted until starting
materials spots disappeared on TLC. The reaction was poured into water,
adjusted to a pH of 9 with 10% aqueous NaOH, and extracted with chloroform for
three times (15mL per time). The extract was washed with water, and dried over
anhydrous magnesium sulfate. The solvent was distilled out at a reduced
pressure to obtain a product. The product was dissolved in 2mL anhydrous
ethanol, and 3mL of saturated anhydrous ethanol-HCI solution was added
dropwise, and the mixture was standed overnight. The precipitated solid was
filtered out, washed with ethyl acetate, dried to obain
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl aromatic carboxylate hydrochloride.
The following compounds were synthesized and characterized according to
the above reaction scheme.
Example 1: Synthesis of aromatic carboxylic acid esters (formula (III)) of
the compound [formula (II)]

3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate is given below as
example.
To 10mL anhydrous pyridine, the compound [formula (II)] 0.43g (1 mmol)
was added, dissolved under stirring at room temperature, benzoyl chloride 0.28g
(2mmo!) was added dropwise, and the reaction was conducted until starting
materials spots disappeared on TLC. The reaction was poured into water,
adjusted to a pH of 9 with 10% NaOH, and extracted with chloroform for three
times (15mL per time). The extract was washed with water, and dried over
anhydrous magnesium sulfate. The solvent was distilled out to obtain a product.
The product was dissolved in 2mL anhydrous ethanol, 3mL of saturated
anhydrous ethanol-HCI solution was added dropwise, and the mixture was
standed overnight. The precipitated solid was filtered out, washed with ethyl
acetate, dried to obain 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]-
ethyl}-2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate
dihydrochloride 0.33 g. The product was convereted to obtain
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-piperidin-1-yl]ethyl}-2-methyl-4-oxo-6,7,
8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate 0.30 g. Melting point is
The following compounds were synthesized and characterized according to
this method.
Compound 1. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]-
ethyl}-2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate
1H-NMR(CDCI3):2.10-2.27(8H,rn,-CH2-), 2.29(3H,s,-CH3), 2.58, 2.78,
3.18(6H,t,t,t,>N-CH2-), 3.91, 4.11(2H,m,m,-CON-CH2-), 3.10(1H,m,- >-CH-),
6.02(1 H,t,=-CH-0-), 7.02-8.06 (8H,m,Ar-H ).
13CNMR: 20.61, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C),
50.74, 79.57, 99.70, 107.36, 114.31, 118.63, 126.83, 129.07(2C), 130.09(2C),
130.97, 133.02, 141.91, 143.75, 155.11, 157.00, 163.78, 165.58, 166.57.
Compound 2. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate
The reaction conditions were substantively the same, except that
benzoylchloride was replaced with 4-methylbenzoylchloride to obtain 0.36g of
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate.
Mp: 112.1-113.5°C.
1H-NMR(CDCI3): 2.04-2.34(8H,m,-CH2-), 2.40(6H,s,-CH3), 2.56,2.80,2.91
(6H,t,t,t,>N-CH2-), 3.22(1H,m,-N=-CH-), 3.91,4.11 (2H,m,m, -CON-CH2-), 5.96
(1H,t,=-CH-O-), 6.98-7.99 (7H,m,Ar-H ).
13C-NMR 20.61, 21.40, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65,
48.73(2C), 50.74, 79.57, 99.70, 107.36, 114.35, 118.63, 125.84, 126.43,
127.21(2C), 129.23(2C), 141.90, 141.91, 143.75, 155.11, 157.00, 163.78, 165.58,
166.57.
Compound 3. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate
The reaction conditions were substantively the same, except that
4-methylbenzoylchloride was replaced with 4-methoxybenzoylchloride to obtain
0.26g 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-2-methyl-
4-0X0-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate, mp.
96.1-98.0°C.
1H-NMR(CDCI3): 2.08-2.22(6H,m,-CH2-), 2.28(3H,s,-CH3), 2.39(2H,t,-CH2-),
2.65,2.8213.27(6H,t1t,t,>N-CH2-), 3.14(1H,m,-N =-CH-), 3.83(3H,s,-OCH3), 3.89,
4.10 (2H,m,m, -CON-CH2-), 5.93(1 H,t,=-CH-O-), 6.91-8.10 (7H,m,Ar-H ).
13C-NMR: 20.61, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C),
50.74, 55.25, 79.57, 99.70, 107.36, 114.24(2C), 114.35, 118.63, 121.80, 125.84,
130.82(2C), 141.91, 143.75, 155.11, 157.00, 162.50, 163.78, 165.58, 166.57,
Compound 4. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorobenzoate
The reaction conditions were substantively the same, except that
4-methylbenzoylchloride was replaced with 4-fluorobenzoylchloride.
1HNMR: d 1.94-2.12(6H m-CH2-), 2.19 (3H s CH3), 2.20-2.30(4H t-NCH2-),
2.48(2H t-CH2-),2.54(2H t-CH2N-), 2.58(1 H m >CH-), 2.61-2.76(2H
m-CH2-),3.43-3.55(2H t-CH2N-), 5.85(1H t >CHOC(C=O)-), 6.61(1H m Ar-H),
7.17-8.03(6H m Ar-H).
13C-NMR: 20.61, 22.90, 23.79, 27.69(2C), 33.66, 34.27, 42.65, 48.73(2C),
50.74, 79.57, 99.70, 107.36, 114.31, 115.86(2C), 118.63, 125.84, 126.36,
130.25(2C), 141.91, 143.75, 155.11, 157.00, 163.87, 164.88, 165.58, 166.57.
Melting point: 226.1 -227.6°C (hydrochloride).
Example 2: Synthesis of carbonyl carboxylic acid esters (formula (IV)) of
the compound [formula (II)]

A. General methods and processes
Reaction scheme:

wherein Y is a saturated alkyl having 1-20 carbon atoms or an unsaturated
alkyl having 2-20 carbon atoms or a cycloalkyi having 4-20 carbon atoms, such as
methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and various
isomers thereof, cyclohexyl, etc.; or an aryl having 7-20 carbon atoms, such as
phenyl, tolyl, methoxyphenyl, etc.
Compound 5. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate
hydrochloride
To 30ml anhydrous dichloromethane and 3ml anhydrous pyridine, 2.0g
(4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at
room temperature, then 1.0g (9.38mmol) ethyl chloroformate was added dropwise,
and reacted until starting materials spots disappeared on TLC. The reaction was
poured into a sufficient amount of water, adjusted to pH of 9 with 10% aqueous
NaOH solution, and extracted with dichloromethane for three times (30ml per
time). The extract was washed with water, dried over anhydrous magnesium
sulfate, and distilled at a reduced pressure to remove solvent. The residue was
dissoved in 5ml anhydrous ethanol, and then 5ml of saturated anhydrous
ethanol-HCI solution was added dropwise. After standing overnight, the
precipitated solid was filtered out, washed with ethyl acetate, and dried to obtain
1.60g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-
oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate hydrochloride,
mp.: 229.0-229.5°C.
1H-NMR(CDCI3): 1.32(3H,t,-CH3), 2.02-2.60(8H,m,-CH2-), 2.39(3H,s,Ar-CH3),
2.40-3.47(6H,m, >N-CH2-), 3.22(1 H,m,-N=-CH-), 3.91,4.11(2H,m,m,-CON-CH2-),
4.23(2H,m,-OCH2-), 5.96(1 H,t,=-CH-O-), 7.01-7.22(3H,m,Ar-H ).
13CNMR: 13.93, 20.61, 22.90, 24.02, 27.69(2C), 32.10, 34.27, 42.65,
48.73(2C), 50.74, 62.40, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 126.83,
148.20, 150.05, 155.11, 163.78, 165.08, 166.57.
Compound 6. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate
dihydrochloride
To 30ml anhydrous dichloromethane and 3ml anhydrous pyridine, 2.0g
(4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at
room temperature, then 1.29g (9.38mmol) isobutyl chloroformate was added
dropwise, and reacted until starting materials spots disappeared on TLC. The
reaction was poured into a sufficient amount of water, adjusted to pH of 9 with
10% aqueous NaOH solution, and extracted with dichloromethane for three times
(30ml per time). The extracts were washed with water, dried over anhydrous
magnesium sulfate, and distilled at a reduced pressure to remove solvent. The
residue was dissoved in 5ml anhydrous ethanol, and then 5ml of saturated
anhydrous ethanol-HCI solution was added dropwise. After standing overnight,
the precipitated solid was filtered out, washed with ethyl acetate, and dried to
obtain 1.65g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-
methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate
dihydrochloride, mp.: 242.1-243.5°C.
1H-NMR(DMSO-d6): 0.88(6H,d,-CH-),
2.25(3H,s, Ar-CH3), 2.99- 3.12 (6H,m, >N-CH2-), 3.50(1H,m,-N=-CH-), 3.70,3.97
(6H,m,m, -CON-CH2-, -OCH2-,Ar-CH2-), 5.55(1 H,t, =-CH-O-), 6.56(1 H.br.HCI),
7.31-8.18 (3H,m,Ar-H ), 11.02(1H,br,HCI).
13CNMR: 19.12(2C), 20.61, 22.90, 24.02, 27.83, 27.69(2C), 32.10, 34.27,
42.65, 48.73(2C), 50.74, 70.66,81.82, 99.70, 107.36, 114.31, 118.63, 120.82,
126.83, 148.20, 150.05, 155.11, 163.78, 165.08, 166.57.
Compound 7. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate
dihydrochloride
To 30ml anhydrous dichloromethane and 3ml anhydrous pyridine, 2.0g
(4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at
room temperature, then 1.42g (9.38mmol) pentyl chloroformate was added
dropwise, and reacted until starting materials spots disappeared on TLC. The
reaction was poured into a sufficient amount of water, adjusted to pH of 9 with
10% aqueous NaOH solution, and extracted with dichloromethane for three times
(30ml per time). The extracts were washed with water, dried over anhydrous
magnesium sulfate, and distilled at a reduced pressure to remove solvent. The
residue was dissoved in 5ml anhydrous ethanol, and then 5ml of saturated
anhydrous ethanol-HCI solution was added dropwise. After standing overnight,
the precipitated solid was filtered out, washed with ethyl acetate, and dried to
obtain 1.72g of 3-{2-[4-(6-fluoro- 1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-
methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate
dihydrochloride, mp.: 232.5-233.6°C.
1H-NMR(DMSO-d6): 0.86(3H,d,-CH3), 1.30-1.61 (8H,m,-CH2-),
1.97-2.48(8H,m,-CH2-), 2.32(3H,s, Ar-CH3), 2.99-3.71 (6H,m, >N-CH2-),
3.71(3H,m,- N =-CH-, Ar-CH2-), 3.50,3.90 (6H,m,m,-CON-CH2-),4.16
(2H,m,-OCH2-),), 5.55(1H, t,=-CH-O-),7.32-8.25(3H,m,Ar-H ),8.46(1H,br,
HCI),11.26 (1H,br, HCI).
13CNMR:13.99, 20.61, 22.42, 22.90, 24.02, 27.69(2C), 28.23, 28.48, 32.10,
34.27, 42.65, 48.73(2C), 50.74, 64.64, 81.82, 99.70, 107.36, 114.31, 118.63,
120.82, 126.83, 148.20, 150.05, 155.11, 163.78, 165.08, 166.57.
Compound 8. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyljethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate
hydrochloride
To 10ml anhydrous dichloromethane and 1ml anhydrous pyridine, 2.0g
(4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at
room temperature, then 1.48g (9.38mmol) phenyl chloroformate was added
dropwise, and reacted until starting materials spots disappeared on TLC. The
reaction was extracted with dichloromethane for three times (15ml per time). The
extracts were washed with water, dried over anhydrous magnesium sulfate, and
distilled at a reduced pressure to remove solvent. The residue was dissoved in
2ml anhydrous ethanol, and then 3ml of anhydrous ethanol-HCI saturated
solution was added dropwise. After standing overnight, the precipitated solid was
filtered out, washed with ethyl acetate, and dried to obtain 1.51 g of
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate hydrochloride.
Mp.: 186.7-187.8°C.
1H-NMR(CDCI3): 2.03-2.60(8H,m,-CH2-), 2.43(3H,s,Ar-CH3),
3.07,3.11(6H,m,>N-CH2-), 3.46(1H, m,-N =-CH-),3.88, 3.98(2H,m,-CON-CH2-),
5.65(1 H,t,=-CH-O-), 6.78-7.40 (8H,m,Ar-H ), 7.95 (1H,br, HCI).
13CNMR: 20.61, 22.90, 24.02, 27.69(2C), 32.10, 34.27, 42.65, 48.73(2C),
50.74, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 121.48(2C), 125.60, 127.92,
130.09(2C), 142.58, 150.05, 150.35, 155.11, 163.78, 165.08, 166.57.
Melting point: 249.2-251.5°C.
Compound 9. 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-
2-methyl-4-oxo-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl p-nitrophenyl
carbonate hydrochloride
To 10ml anhydrous dichloromethane and 1ml anhydrous pyridine, 2.0g
(4.69mmol) of the compound [formula (II)] was added, dissolved under stirring at
room temperature, then 1.91g (9.38mmol) p-nitrophenyl chloroformate was added
dropwise, and reacted until starting materials spots disappeared on TLC. The
reaction was extracted with dichloromethane for three times (15ml per time). The
extracts were washed with water, dried over anhydrous magnesium sulfate, and
distilled at a reduced pressure to remove solvent. The residue was dissoved in
2ml anhydrous ethanol, then 3ml of anhydrous ethanol-HCI saturated solution
was added dropwise. After standing overnight, the precipitated solid was filtered
out, washed with ethyl acetate, and dried to obtain 1.69g of 3-{2-[4-(6-fluoro-
1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-6,7,8,9-tetrahydro-pyr
ido[1,2-a]pyrimidin-9-yl p-nitrophenyl carbonate hydrochloride.
1H-NMR(CDCI3): 1.78-2.47(8H,m,-CH2-), 2.35(3H,s,Ar-CH3), 2.60,2.95,3.36
(6H,m,>N-CH2-), 3.28(1H, m,- N° =-CH-), 3.83(1H,s,HCI), 3.95,4.03 (2H,m,
-CON-CH2-), 5.58(1 H,t,=-CH-O-), 6.93-8.10(8H,m,Ar-H ),7.95 (1H,br,HCI).
13CNMR: 20.61, 22.90, 24.02, 27.69(2C), 32.10, 34.27, 42.65, 48.73(2C),
50.74, 81.82, 99.70, 107.36, 114.31, 118.63, 120.82, 122.18(2C), 125.18(2C),
127.92, 145.38, 148.20, 150.05, 155.11,155.47, 163.78, 165.08, 166.57.
Example 3: Tests of the compounds being metabolized to form the active
component, 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-9-
hydroxy-2-methyl-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one, (the
compound [formula (II)]) in liver cells
40 µg of the Compound 1 of Example 1 (or Compound 2 or Compound 3 or
Compound 5 or Compound 6 or Compound 7 or Compound 8 or Compound 9)
was dissolved in 0.01 M potassium phosphate buffer solution (containing 1mM
NADPH), mixed with 25 uL of human liver cells S9 (20mg protein/mL, H961),
cultured at 37°C for 2 hours, and then the mixture was quenched with
concentrated perchloric acid. After the precipitated proteins were removed by
centrifugation, the obtained supernatant solution was adjusted to pH of 3 with
concentrated potassium phosphate solution, and centrifuged again. The obtained
supernatant was directly injected into HPLC for analysis.
The metabolism results were shown in Table 1. The metabolic rates of the
compounds being metabolized in liver cells for 2 hours to form the active
component 3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1 -piperidinyl]ethyl}-9-
hydroxy-2-methyl-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-4-one (the compound
[formula (II)]) ranged from 70% to 95%, depending on the different ester groups.

Example 4: Measurement of the absolute bioavailability - Beagle tests of
the compound [formula (II)] and its prodrugs, the compounds 1, 2, 3, 5, 6, 7 and 8
Twenty one beagles weighing about 10kg were divided into 7 groups, and
intragastrically administered the compounds 1, 2, 3, 5, 6, 7 and 8 at a dosage of
9.4 µmol/beagle, respectively. Blood samples were taken at the predetermined
time points, and the concentrations of the active metabolite (the compound
[formula (II)]) and prodrugs in blood were measured. In the meantime, three
beagles weighing about 10kg were intravenously administered with the
compound [formula (II)] at a dosage equimolar to the prodrug, as the control
group, and the concentrations of the compound [formula (II)] in blood were
measured.
The results were shown in Fig.1 and Table 2. The prodrugs were immediately
metabolized almost completely to form the active metabolite in beagle body, the
compound [formula (II)] upon being administrated parenterally, and the
concentrations of the original compounds were very low (see: Fig.lC). The results
also indicateed that the bioavailability of the prodrugs of the compound [formula
(II)] were significantly higher than that of Invega (28%). Particularity, the prodrugs
of carbonate type had a very remarkable improvement of bioavailability.

Example 6: Preparation of oral conventional tablets

Tablets were obtained by direct tabletting, and each tablet contained 6mg of
active ingredient (expressed in the compound [formula (II)]). The oral
conventional tablets were subjected to dissolution tests, and the results were
shown in table 3 below.

Granules were obtained by using conventional fluidized bed.

After the coating was dried, the coated granules were filled into hard gelatin
capsules, each capcule contain 6mg of the active ingredient (expressed in the
compound [formula (II)]), and the coating degree was 6%. The capsules were
subjected to dissolution tests according the method specified in the
Pharmacopoeia of the People's Republic of China. The results were shown in
table 4 below.

What is claimed is:
1. A compound of formula (I),

wherein ,
the chiral center (*) can be R or S or RS (racemic mixture);
R is an aryl having 7-20 carbon atoms; or a saturated alkoxy having 1-20
carbon atoms or an unsaturated alkoxy having 2-20 carbon atoms or a
cycloalkoxy having 4-20 carbon atoms or an arylalkoxy having 7-20 carbon atoms;
or
an optical isomer thereof or a pharmaceutically salt thereof.
2. The compound of formula (I) according to claim 1, characterized in that, in
the compound of formula (I),
R is an aryl having 7-20 carbon atoms, preferably

wherein, R4 and R5 independently are hydrogen, a saturated alkyl having
1-6 carbon atoms or alkoxy having 1-6 carbon atoms, an unsaturated alkyl having
2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably hydrogen,
methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl.
3. The compound of formula (I) according to claim 1, characterized in that, in
the compound of formula (I),
R is a saturated alkoxy having 1-20 carbon atoms or an unsaturated alkoxy
having 2-20 carbon atoms or a cycloalkoxy having 4-20 carbon atoms, preferably,
R is a saturated alkoxy having 1-10 carbon atoms or an unsaturated alkoxy
having 2-10 carbon atoms or a cycloalkoxy having 4-10 carbon atoms; or an
arylalkoxy having 7-20 carbon atoms, preferably:

wherein , R6 and R7 independently are hydrogen, a saturated alkyl having
1-6 carbon atoms or alkoxy having 1-6 carbon atoms, an unsaturated alkyl having
2-6 carbon atoms, OH, CI, F, CN, carboxyl and ester group; preferably hydrogen,
methyl, ethyl, methoxy, ethoxy, fluorine or carboxyl.
4. A salt of the compound of formula (I) according to claim 1, characterized
in that the salt of the compound is hydrochloride, sulfate, maleate, succinate, and
other salts formed with a pharmaceutically acceptable acid.
5. The compound according to any one of claims 1-5, wherein the compound
is selected from the group consisting of:
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl benzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylbenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylbenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxybenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxybenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxybenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorobenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorobenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorobenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-carboxybenzoate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl methyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl ethyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl propyl carbonate,
3.{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}--2-methyl-4-oxo
-6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopropyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl butyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isobutyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl tert-butyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylbutyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl n-pentyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-pentyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-pentyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazoi-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl isopentyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl neopentyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl hexyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl cyclohexyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl phenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methylphenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methylphenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methylphenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-methoxyphenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-methoxyphenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-methoxyphenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 2-fluorophenyl carbonate,
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 3-fluorophenyl carbonate, and
3-{2-[4-(6-fluoro-1,2-benzoisoxazol-3-yl)-1-piperidinyl]ethyl}-2-methyl-4-oxo-
6,7,8,9-tetrahydro-pyrido[1,2-a]pyrimidin-9-yl 4-fluorophenyl carbonate, and
various salts and optical isomers thereof.
6. A pharmaceutical composition comprising a compound according to any
one of claims 1-5 or an optical isomer or a pharmaceutically acceptable salt
thereof, and a pharmaceutically acceptable carrier.
7. Use of a compound according to any one of claims 1-5, or an optical
isomer or pharmaceutically acceptable salt thereof in the manufacture of a
medicament as antagonist of neurotransmitters for the treatment of the related
mental disorders, such as schizophrenia.
8. The pharmaceutical composition according to claim 6, wherein the
composition is administrated by oral, injection, transdermal, intranasal, or
mucosal mode or by inhalation administration.
9. The pharmaceutical composition according to claim 8, wherein the
composition is presented in conventional, sustained-release, controled-release,
site specific delivery or fast release dosage form, preferably oral
sustained-release dosage form, reservoir-type injection such as
sustained-release microspheres, implants.

The present invention relates to a compound of formula (I), an optical isomer or a pharmaceutically acceptable salt thereof, its preparation and uses, wherein R is defined as herein. Such compounds can be presented as an optical isomer or a racemic mixture. The compounds can be metabolized in vivo to form a pharmacologically active substance as antagonist of neurotransmitters, and can be used for the treatment of the related mental disorders such as schizophrenia.

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Patent Number

279002

Indian Patent Application Number

3752/KOLNP/2009

PG Journal Number

02/2017

Publication Date

13-Jan-2017

Grant Date

06-Jan-2017

Date of Filing

28-Oct-2009

Name of Patentee

LI, YOUXIN

Applicant Address

NO. 402, HUA YUAN YI CUN LIU DONG, TIANPING ROAD, TIANYUAN DISTRICT, ZHUZHOU CITY, HUNAN 412000, CHINA

Inventors:

#	Inventor's Name	Inventor's Address
1	LI, YOUXIN	NO. 402, HUA YUAN YI CUN LIU DONG, TIANPING ROAD, TIANYUAN DISTRICT, ZHUZHOU CITY, HUNAN 412000, CHINA

PCT International Classification Number

C07D471/04; A61K31/505; A61P25/18

PCT International Application Number

PCT/CN2008/000803

PCT International Filing date

2008-04-18

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	200710098304.6	2007-04-19	China