Title of Invention	"PIPERAZINEDIONE COMPOUNDS"
Abstract	Piperazinedionc compounds of the formula (I), wherein each of— and =, independently, is a single bond or a double bond; A is H or CH(RaRb) when = is a single bond, or C(RaRb) when — is a double bond; Z is R3O-(Ar)-B, in which B is CH(Rc) when — is a single bond, or C(RC) when = is a double bond; Ar is heteroaryl; and R3 is H, alkyl, aryl, heteroaryl, C(O)Rd, C(O)ORd, C(O)NRdRe, or SO2Rd, each of R1 and R2, independently, is H C(O)Rd, C(O)ORd, C(O)NRdRe, or SO2Rd; and each of Ra, Rb, Rc, Rd. and Re, independently, is H, alkyl, aryl, heteroaryl, cyclyl, or heterocyclyl. Optionally, Ra and Rb taken together are cyclyl or heterocyclyl; and, also optionally, R1 and Ra or R1 and Rb taken together are cyclyl or heterocyclyl.

Title of Invention

"PIPERAZINEDIONE COMPOUNDS"

Abstract

Piperazinedionc compounds of the formula (I), wherein each of— and =, independently, is a single bond or a double bond; A is H or CH(RaRb) when = is a single bond, or C(RaRb) when — is a double bond; Z is R3O-(Ar)-B, in which B is CH(Rc) when — is a single bond, or C(RC) when = is a double bond; Ar is heteroaryl; and R3 is H, alkyl, aryl, heteroaryl, C(O)Rd, C(O)ORd, C(O)NRdRe, or SO2Rd, each of R1 and R2, independently, is H C(O)Rd, C(O)ORd, C(O)NRdRe, or SO2Rd; and each of Ra, Rb, Rc, Rd. and Re, independently, is H, alkyl, aryl, heteroaryl, cyclyl, or heterocyclyl. Optionally, Ra and Rb taken together are cyclyl or heterocyclyl; and, also optionally, R1 and Ra or R1 and Rb taken together are cyclyl or heterocyclyl.

Full Text	BACKGROUND The treatment of tumor can be approached by several modes of therapy, including surgery, radiation, chemotherapy, or any combination of any of these treatments. Among them, chemotherapy is indispensable.for inoperable or metastatic forms of cancer. Considering the diversity of tumors in terms of cell type, morphology, growth rate, and other cellular characteristics, the U.S. National Cancer Institute (NCI) has developed a "disease-oriented" approach to anti-tumor activity screening. Boyd, M.R (1989) In Principle of Practice of Oncology Devita, J.T., Hellman, S., and Rosenberg, S.A. (Eds.) Vol. 3, PPO Update, No. 10. This in vitro screening system is based on human tumor cell line panels consisting of approximately 60 cell lines of major human tumors (e.g., leukemia, lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer, or breast cancer), and serves as a tool for identifying compounds that possess anti-tumor activities. Of particular interest are the anti-tumor compounds that function via one or more of the following four mechanisms: (1) inhibiting G3/M progression of the cell cycle, which might eventually induce the apoptosis in tumor cells (Yeung et ah (1999) Biochem. Biophys. Res. Com. 263:398-404); (2) disturbing tubulin asserobly/dissembly, which may inhibit the cell mitosis and induce the cell apoptosis (Panda et ah (1997) Proc. Natl Acad, Sci. USA 94:10560-10564); (3) inhibiting endothelial cell proliferation and angiogenesis effect (Witto et ah (1998) Cancer Metastasis Rev. 17: 155-161; Prewett et ah (1999) Cancer Res. 59: 5209-5218); or (4) regulating Ras protein-dependent signal transduction pathway (Hemandez-AJcoceba ef ah (2000) CellMol Life Sci. 57: 65-76; Buolamwini (.1999) Cur. Opin. Clie. Biol. 3; 500-509). SUMMARY This invention is based in part on the discovery that piperazinedione compounds have anti-tumor activities, identified by NCI screening system, and function via one OT more of the above-mentioned four mechanisms. An aspect of the present invention relates to piperazinedione compounds of formula: (Formula Removed) Each of and , independently, is a single bond or a double bond; A is H or CHCR'Rb) • when is a single bond, or C(R R1') when = is a double bond. Z is R3O-(Ar)-B, in which B is OH(R') when is a single bond, or C(R) when = is a double bond; Ar is heteroaryl; Rj isH, alkyl, aryl, heteroaryl, C(0)R Referring to the above formula, a.subset of the piperazinedione compounds of this invention is featured by that both = and = are double bonds. In these compounds, Ar is pyridyl linked to B at position 2, Rc is H, R3O is arylalkoxy linked to position 5 of pyridyl, both R1 and R2 are H, one of Ra and Rb is aryl or heteroaryl, and the other of R' and Rb is H. Another subset of the piperazinedione compounds of this invention is featured by that both ==and : are single bonds. In these compounds, Ar is pyridyl linked to B at position 2, Rc is H, R3O is arylalkoxy linked to position 5 of pyridyl, bothR1and R2 are H, one of R" andb is H, aryl, orheteroaryl,-fin.d the other of R'and Rb is H. Alkyl, aryl, heteroaryl, cyclyl, and heterocyclyl mentioned herein include both substituted and unsubstituted moieties, The term "substituted" refers to one or more substituents (which may be the same or different), each replacing a hydrogen atom. Examples of substituents include, but are not limited to, halogen, hydroxyl, amino, alkylamino, arylamino, dialkylamino, diaryl amino, cyano, nitro, mercapto, carbonyl, carbamido, carbamyl, carboxyl, thioureido, thjocyanalo, sulfoamido, C1-C6 alkyl, C1-C6 alkenyl, C1-C6alkoxy, aryl, heteroaryl, cyclyl, heterocyclyl, wherein alkyl, alkenyl, alkoxy, aryl, heteroaryl cyclyl, and heterocyclyl are optionally substituted with C1-C6 alkyl, aryl, heteroaryl, halogen, hydroxyl, amino, mercapto, cyano, or nitro. The term "aryl" refers to a hydrocarbon ring system having at least one aromatic ring. Examples of aryl moieties include, but are not limited to, phenyl, naphthyl, and pyrenyl. The term "hetcroaryr refers to a hydrocarbon ring system having at least one aromatic ring which contains at least one heteroatom such as O, N, or S. Examples of heteroaryl moieties include, but are not limited to, fury!, fluorenyl, pyrrolyl, thienyl, oxazolyl, Imidazolyl, thiazolyl, pyridinyl, pyrimidinyl, quinazolinyl, and indolyl. Another aspect of the present invention relates to a pharmaceutical composition that contains a pharmaceutically acceptable carrier and an effective amount of at least one of the piperazinedione compounds described above. A further aspect of this invention relates to a method for treating tumor (e.g., leukemia, lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer, or breast cancer). The method includes administering to a subject in need thereof an effective amount of the piperazinedione compound having the formula: (Formula Removed) Each of = and = , independently, is a single bond or a double bond; A isH or GH(RaRb) when = is a single bond, or C(RaRb) when = is a double bond; Z is CH(RcRd) when = is a single bond, or C(RcRb) when = is a double bond; each ofR1and R2, independently, is H, C(0)Re, C(0)OR", C(O)NR.tR1, or SO2R'; and each of R', Rb, Rc, Rd, R6, and Rr, independently, is H, alkyl, aryl, heteroaryl, cyclyl, or heterocyclyl, provided that one of Rc and R1 is aryl or heteroaryl. If == is a double bond, ==== is a single bond, and one of Rc-and Rd is H, then the other of Rc and Rd is heteroaryl. Optionally, R' and Rh taken together are cyclyl or heterocyclyl; and, also optionally, Rt and R' or Rj and R* taken together are cyclyl or heterocyclyl. Referring to the above formula, a subset of the just-described piperazinedione compounds is featured by that both = and = are double bonds. In these compounds, one of Rc andRd is 2=pyridy the-othei of Rc and.Rd.is H,.bothR1.and R2 areH, one of Ra and Rb is aryl or heteroaryl, and the other of R' and Rb is H. The 2-pyridyl can be further substituted with 5-arylalkoxy. Another subset of the piperazinedione compounds is featured by that both = and = are single bonds. In these compounds, one of R° and R is 2- pyridyl, the other of Rc and Rd is H, both R1, and Ra are H, one of Ra and Rb Is H, aryl, or heteroaryl, and the other of Ra and Rb is H. Seven exemplary piperazinedione compounds are 3-[(5-benzyoxypyrldin-2-yl)methylidene]-6-phenylmerbylidenepiprazine-2,5-dione, 3-[(5-benzyoxypyridin-2-yl)melhylidene]-6-p-bydroxyphenylmethyIidenepiperazine-2,5-djone, 3-[(5-benzyoxypyridm-2-yl)methylidene]-6-p-fluorophenylmethylidenepiperazie-2,5dione,3-[(5-benzyoxypyridin-2-yl)methyl5dene]-6-p-chlorophenylmethylidenepiperazine-2,5-dione, 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-phenylinetboxy phenylmethylidenepiperazine-2,5-dione, 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-[(thien-2-yl)methylidene3piperazine-2,5-dione, and 3,6-di[(5-pheny]methoxypyridin-2-yl)rnethyI]piperazine-2,5-o,ione. Their structures are shown below: (Formula Removed) The piperazinedione compounds described above include the compounds themselves, as well as their salts and their prodrugs, if applicable. Such salts, for example, can be formed between a positively charged substituent (e.g., amino) on a piperazinedione compound and an anion, Suitable anions include, but are not limited to, chloride, bromide, iodide, sulfate, nitrate, phosphate, citrate, methanesulfbnate, trifluoroacetate, and acetate. Likewise, a negatively charged substituent (e.g., carboxylate) on a piperazinedione compound can form a salt with a cation. Suitable cations include, but are not limited to, sodium ion, potassium ion, magnesium ion, calcium ion, and an ammonium cation such as teteramethylammonium ion. Examples of prodrugs include esters and other phaimaceutically acceptable derivatives, which, upon administration to a subject, are capable of providing piperazinedione compounds described above. Also within the scope of this invention are a composition containing one or more of the piperazinedione compounds described above for use in treating tumor, and the use of such a composition for the manufacture of a medicament for the just-described use. Other features or advantages of the present invention will be apparent from the following detailed description of several embodiments, and also from the appending claims. DETAILED DESCRIPTION The piperazinedione compounds described above can be prepared by methods well known in the art, as well as by the synthetic routes disclosed herein. For example, one can react a piperazine-2,5-dione compound with a heteroaryl formaldehyde to produce an intermediate heteroaryl-methyJidene-pipera2ine-2,5-dione. The intermediate can then bo reduced to heteroaryl-methyl'piperazine-2,5-dione (a compound of this invention), or reacted with a ketone or another formaldehyde, followed by a base treatment, to produce a mixture of piperazinedione isomers, which are cis- or trans- or E- or Z- double bond isomeric forms, The desired isomeric product can be separated from others by high pressure liquid chromatography (HPLC). If preferred, proper functional groups can be introduced into the heteroaryl ring by further modifications. Alternatively, a desired reduced product can be obtained by reacting the product with a reducing agent Shown below is a scheme that depicts the synthesis of seventeen piperazinedione compounds. (Formula Removed) Details of synthesis of Compounds 1-17 are described in Examples 1-17, respectively. To prepare other piperazincdione compounds, the pyridinyl (shown in the above scheme) can be replaced by an aryl or another heteioaryl (e.g., furyl, pyrrolyl, imidazolyl, pyrimidinyl, or indolyl), and one of the two acetyl groups (Ac) on the piperazincdione ring (also shown in the above scheme) can be replaced by another substituent (e.g., carbonyl, carbamido, carbamyl, or carboxyl). Note that the piperazinedionc compounds contain at least two double bonds, and may further contain one or more asymmetric centers. Thus, they can occur as racemares and racemic mixtures,single enantiomers, individual diastercomers, diastereomcric mixtures, and cis- or trans- or E- or Z- double bond isomeric forms. All such isomeric forms arc contemplated. Also within the scope of this invention is a pharmaceutical composition that contains an effective amount of at least one piperazinedione compound of the present invention and a pharmaceutically acceptable carrier. Further, this invention covers a method of administering an effective amount of one or more of the piperazinedione compounds described in the "Summary" section above to a subject in need of tumor treatment The piperazinedione compounds can function via one or more of the above described action mechanisms, or via any other mechanism. "An effective amount" refers to the amount of the compound which is required to confer a therapeutic effect on the treated subject. The interrelationship of dosages for animals and humans (based on milligrams per meter squared of body surface) is described in Freireich ei ah, (1966) Cancer Chemother Rep 50:219. Body surface area may be approximately determined from height and weight of the patient. See, e.g., Scientific Tables, Geigy Pharmaceuticals, Ardley, N.Y., 1970, 537. An effective amount of the piperazinedione compounds can range from about 0.1 mg/Kg to about 50 mg/Kg. Effective doses will also vary, as recognized by those skilled in the art,idepending on the types of tumors treated, route of administration, excipient usage, and the possibility of co-usage with other therapeutic treatments such as use of other anti-tumor agents or radiation therapy. To practice the method of the present invention, a piperazinedione compound-containing composition can be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. The term "parenteral" as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intraarticular, intraarterial, intrasynovial, intrasternal, intrathecal, intraleslonal and intracranial injection or infusion techniques. A sterile injectable composition, for example, a sterile injectable aqueous or oleaginous suspension, can be formulated according to techniques known in the art using suitable dispersing or wetting agents (such as, for example, Tween 80) and suspending agents. The sterile injectable preparation can also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that can be employed are mannitol, water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium (e.g., synthetic mono- or diglycerides). Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmHceutjcally-acceptable oils, such as olive oil or castor oil, especially in their polyaxyethylatod versions. These oil solutions or suspensions can also contain a long-chain alcohol diluent or dispersant, or carboxymethyl cellulose or similar dispersing agents. Other commonly used surfactants such as Tweens or Spans or other similar emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceuticaljy acceptable solid, liquid, or other dosage farms can also be used for the purposes of formulation. A composition for oral administration can be any orally acceptable dosage form including, but not limited to, capsules, tablets, emulsions and aqueous suspensions, dispersions and solutions. In the case of tablets for oral use, carriers which are commonly used include lactose and core starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried corn starch. "When aqueous suspensions or emulsions arc administered orally, the active ingredient can be suspended or dissolved in an oily phase combined with emulsifying or suspending agents. If desired, certain sweetening, flavoring, or coloring agents can be added. A nasal aerosol or inhalation composition can be prepared according to techniques well-known in the art of pharmaceutical formulation and can be prepared na solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbona, andVor other solubilizing or dispersing agents known in the art A piperazinedione compound-containing composition can also be administered in the form of suppositories for rectal administration. The carrier in the pharmaceutical composition must be "acceptable" in the sense of being compatible with the active ingredient of the formulation (and preferably, capable of stabilizing it) and not deleterious to the subject to be treated. For example, solubilizing agents such as cyclodextrins, which form specific, more soluble complexes with the piperazinedione compounds, or one or more solubilizing agents, can be utilized as pharmaceuticalexcipientsfor delivery of the piperazinedione compounds. Examples of other carriers include colloidal silicon dioxide, magnesium stearate, cellulose, sodium lauryl sulfate, and D&C Yellow # 10. The piperazinedione compounds can be preliminarily screened for their efficacy in treating cancer by one or more of the following in vitro assays, One assay is based on the NCI screening system, which consists of approximately 60 cell lines of major human tumors. See Monks, et al. (1991) JNCl 7. Natl Cancer Insz. 83: 757-766; Alley, et al. (1988) Cancer Res. 48: 589-601; Shoemaker, et al. (1988) Frog. Clin Biol Res. 276:265-286; and Stinson, et al. (1989) Proc Am. Assoc. Cancer Res. 30: 613. Briefly, a cell suspension that is diluted according to the particular cell type and the expected target cell density (5,000-40,000 cells per well based on cell growth characteristics) is added (100 µL) into a 96-well microliter plate. A pre-incubation is preformed at 37° C for 24 hr. Dilutions at twice of an intended lest concentration are added at time zero in 100 µL aliquots to each well of the microliter plate. Usually, a test compound is evaluated at five 10-fold dilutions. In a routine testing, the highest concentration of the test compound is 10-4 M. Incubations are performed for 48 hr in 5% CO2 atmosphere and 100% humidity. The cells are assayed by using the sulforhodamine B assay described by Rubinstein, et al'. (1990, JNCl J. Natl Cancer Inst. 82:1113-1118) and Skehan, et al. (1990, JNCl, J. Natl Cancer Inst 82: 1107-1112). A plate reader is used to read the optical densities and a microcomputer processes the optical densities into the special concentration parameters. The NCI has renamed an IC50 value, the concentration that causes 50% growth inhibition, a GI50 value to emphasize the correction for the cell counted at time zero; thus, the GI50 measures the growth inhibitory power of the test compound. See Boyd, et al. (1992) In Cytotoxic Anticancer Drugs: Models and Concepts for Drug Discovery and Development; VlEriote, F.A.; Corbett, T.H.; Baker, L.H. (Eds.); Kluwer Academic: Hingham, MA, pp 11-34 hvanother assay, a piperazinedione compound is tested for its cytotoxicity on PC-3 cells (a prostate cancer cell line). More specifjcally, cells are incubated with a test compound in a serum-free medium for 24 hr. The cytotoxic effect can be determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method described in Boyd (In Principle of Practice of Oncology Devita, J.T., Hellman, S., and Rosenberg, S.A. —(Eds.)-Vol. -3-,PPOUpdate,-No-l-Q, 1989).- Another in vitro assay can be used to evaluate the efficiency of a piperazinedione compound in arresting the cell cycle progression. More specifically, a test piperazinedione compound is added to PC-3 cells in a concentration-dependent manner using propidium iodide-stained flow cytometric assessment The cell population of sub-Go/Gi, Gc/Gj. S, and G2/M phase is then determined. In addition, the effect of a piperazinedione compound on fee Ras activity can be examined to determine its regulation of Ras protein-dependent signal transduction pathway. The anti-tumor activity of a piperazinedione compound can be further assessed by an in vivo animal model. Using SCID mice as the model, PC-3 cells are subcutaneously injected into the mice to develop a prostate tumor. The anti-tumor activity of* piperazinedione compound is determined after treatment. Additionally, the anti-tumor activity of a piperazinedione compound can also be evaluated using in vivo anti-angiogenesis testing. For example, nude mice can be used to test the effect of a piperazinediooe compound on bFGP-induced angiogenesi9. A matrigel with bFGF or vscular endothelial growth factor (VEGF) is subcutaneously injected into a mouse with concurrent intraperitoneal administration of a piperazinedione compound. After several days of incubation, the matrigel is cut down for examination of angiogeneais. Without further elaboration, it is believed that the above description has adequately enabled the present invention. The following specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. All of the publications cited herein are hereby incorporated by reference in their entirety. Example 1: Synthesis of 3-[(5-benzyoxypyridin-2-yl)meihylidene]-6-phenylmethyIidene piperazine-2,5-dione (Compound 1). l,4-Diacetyl-piperazine-2,5-dione (8.6 g) was added to a solution of 5-berizyoxypyridin-2-yl-forrnaldeb.yde (4.0 g) in 5.6 mL of triethylamine and 40 mL of dimethylformamide. The mixture was stirred at room temperature for 16 hr and then cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 5.4 g (77%) of l-acetyl-3-[(5-benzyoxypyridin-2-yl)methylidene]piperazme-2,5-dione-(CompoundA.). mp: 189-191°C. 1HNMR (400MHz, DMSO): δ2.52 (s, 3H), 54.54 (s, 3H), S4.33 (a, 2H), 55.25 (s, 2H), 56.85 (s. 1H), 57.384-67.488 (m, 5H, aromatic), δ7.499 (d, J-8.8, 1H), 57.689 (d, J=8.8, 1H), 68.533 (s, 1H)} and 512.147 (s, 1H). Compound A (3.51 g) was added to a 40 mL of dimethylfonnamide solution containing equal molar of benaaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 60°C for 16 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 33 g (83%) of the desired produrt 3-[(5-ben2yoxypyridin-2-yl)methylidene]-6-phenylmethylidenepiperazlnc-2,5-dione (Compound 1) as a mixture of isomers. The mixture was predominately the ZZ and EZ isomers. mp: 223-22S°C, 1HNMR (400MHZ, DMSO): 65.243 (a, 2H), 56,695 (s, 1H), 56.812 (s, 1H). 57.346-57.634 (m, 12H, aromatic), δ8.528 (s, 1H), 510.245 (s, 1H), and 512.289 (s, 1H). Example 2: Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-hydroxyphenyI methylidenepiperazine-2,5-dione (Compound 2). Compound A (3.51 g), obtained from Example 1, was added to a 40 mL of dunethylforrnamide solution containing 1.5 g of 4-hydroxybenzaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 130°C for 16 hr and cooled at icebath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3.3 g (83%) of the desired 3-[(5-benzyoxypyridra-2-yl) methylidene]-6-p-hydroxyphenylmethylidenepiperazine-2,5-dione (Compound 2). mp: 260-263°C. 1HNMR (400MHz, DMSO): δ5.244 (s, 2H), 16.669 (s, 1H), 56.753 (s, 1H), 86.79B (a, 1H, aromatic), δ6.819 (s, 1H, aromatic), S7.347-87.647 (m, 9H, aromatic), δ9.821 (s, 1H), 510.064 (s, 1H), and 812.216 (s, 1H). -Example 3 :Synthesis-of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-methoxyphenyl methy)idenepiperazine-2,5-dione (Compound 3). Compound A (3.51 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 1.4 g of 4-methoxybenzaldebyde and 4 equivalents of triethylamine. The solution was reluxed at 130°C for 16 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3.3 g (83%) of the desired 3-[(5-benzyoxypyridin-2-yl) roethylidene]-6-methoxyphenylmethylidenepipera2iae-2,5-dione (Compound 3). rop: 238-240°C. 1HNMR (400MHz, DMSO): S5.244 (s, 2H), 56.669 (s, 1H), 66.753 (a, 1H), 56.79S (s, 1H, aromatic), δ6,819 (s, 1H, aromatic), δ7.347~S7.647 (m, 9H, aromatic), δ9.821 (s, 1H), 510.064 (s, 1H), and 512.216 (s, IH). Example 4: Synthesis of 3-[(5-benzyoxypyTidb-2-yl)methylidene]-6-p-fluorophenyl methylidenepipera2ine-2,5-dione (Compound 4). Compound A (3.51 g), obtained from Example 1, was added to a 40 mL of dimethylfonnamide solution containing 1.3 g of 4-fluoro benzaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 130CC for 16 hr and cooled at ice bafh to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3,12 g (75%) of the desired 3-[(5-benryovypyrIdin-2-yl)methylidene] -6-p-fluorophenylmethylidenepiperazine-2,5-dJone (Compound 4). rap: 242-244°C, 1HNMR (400MHz, DMSO); 65.237 (s, 2H), 86:688 (s, 1H), 66.794 (s, 1H), 57.209-S7.624 (m, 1 1H, aromatic), 68.520 (s, 1H), 510.348 (s, 1H), and 512.279 (s, IH). Example 5: Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-chlorophenyl methylidenepiperazinc-2,5dione (Compound 5). Compound A (3.51 g), obtained from Example 1, was added to a40 mL of dhnethylformamide solution containing 1.3 g of 4-chlorobenzaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 130°C for 16 hr and cooled at ice bath to produce a yellow precipitate. Then the precipitate was collected and washed with ethyl acetate to give 3-45 g (80%) of the desired 3-[(5-benzyoxypyridin-2-yl)methylidcaoe]-6-p-chlorophenylmethylidenepiperazine-2,5-dione (Compound 5). rap: 250-251oC. Example 6: Synthesis of 3-[(5-ben2yoxypyridin-2-yl)methylidene]-6-p-benzyoxyphenylmethylidene piperazine-2,5-dione (Compound 6). Compound A (3.51.g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 1.45 g of 4-benzyoxybenzaIdehyde and 4 equivalents of triethylamine. The solution was refluxed at 130°C for 16 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected, washed with ethyl acetate, and recrystallized from dimethylformamide to give 3.45 g (80%) of the desired 3-[(5-benzyoxypyridin-2-yl)methylideneJ-6-p-ben2yoxyphenylmethylidencpiperazine'2,5-dione (Compound 6). mp: 253-255°C. 1HNMR (400MHz, DMSO): δ5.142 (s, 2H), 55.235 (s, 2H). 56.672 (s, 1H), 56.777 (s, 1H), S7.041~57.639 (m, 16H, aromatic), δ?_520 (s, 1H), 510.180 (s, 1H), and 512.235 (a, IH). Example 7; Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-[(furan-2-yl) mcdvylidene]piperazine-2,5-dione (Compound 7). Compound A (2.8 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 2 mL of furfural and 4 equivalents of triethylamine. The solution was refluxed at 60°C for 48 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected, washed with ethyl acetate, and recrystallized from dimethylformamide to give 2,5 g (80%) of the desired 3-[(5-benzyoxypyridin-2-yl)methylidenc)-6-[(furan-2-yl)mcthylidene]piperazJne>2,5-dione (Compound 7). mp: 256-2S7°C. JHNMR (400MHz, DMSO): 65.245 (s, 2H), 56.656 (d, J=1.6, 1H), 86.664 (d, JM.6, 1H), 56.685 (s, 1H), 56.720 (s, 1H), 57.349-57.942 (m, 8H, aromatic), δ8.527 (s, 1H), 59.515 (s, 1H), and 512.312 (s, IH). Example 8-Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylicene]-6-[(thien-2-yl) methylidene]piperazine-2,5-dione (Compound 8). Compound A (2.8 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 2 mL of thiophene-2-carbaldehyde and 4 equivalents of triethy]amine. The solution was refluxed at 60°C for 2 days and cooled at ice bath to produce a yellow precipitate. The precipitate -was then collected, a -washed with ethyl acetate, and recrystallized from dimethyiformamide to give 1.9 g (59%) of the desired 3-[(5- benzyoxypyridin-2-yl)methylidene]-6-[(thiophene-2-yl)methylidene]piperazine-2,5-dionc (Compound 8). rap: 215-217°C. 1HNMR. (400MHz, DMSO): δ5.245 (s, 2H), 86.716 (s, 1H), 56.974 (s, 1H), 57.186 (a, 1H), 57.384-57.746 (m, 9H, aromatic), δ8.525 (s, 1H), 59.753 (s, 1H), and 512.288 (s, 1H). Example 9: Synthesis of 3-[(5-benzyloxypyridin-2-yl)methylidene]-6-[(2-pyridinyl) methylidene]piperazine-2,5-dione (Compound 9). Compound A (2.8 g). obtained from Example 1, was added to a 40 mL of dimethyiformamide solution containing 2 mL of pyridine-2-carbaIdehyde and 4 equivalents of triethylamine. The solution was refluxed at 60°C for 2 days and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected, a washed with ethyl acetate, and recryslallized from dimethyiformamide to give 2.7 g (85%) of the; desired 3-[(5-benzyloxypyridin-2-yl)methyIJdene]-6-[(2-pyridinyl)methylidene]pipera2ine-2,5-dione (Compound 9). mp: 248-250°C. 1HNMR (400MHZ, DMSO): δ5.246 (s, 2H), 56.709 (s, 1H). 56.788 (s, 1H), δ7.349-δ7.661(m,8H,aromatic),δ7,923 (d,J=81H,aromatic), δ8.473(d,J=3.6,1H.) 58.533 (d, J=2.8,1H), 58.680 (d, J=2,1H), SI 0.667 (s, 1H), and 512.324 (s, 1H). Example 10: Synthesis of 3,6-di[(5-phenylmethoxypyridin-2-yl)methylidenc}pipera2ine -2,5-dione (Compound 10). Compound A (0.31 g), obtained from Example 1, was added to a 40 mL of dimethyiformamide solution containing equal molar of 5-benzyoxypyridin-2-yl-formaldehyde and-4-equivalents of triethylamine-The soluation was rofluxed at 130°C overnight and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 0.36 g (80%) of the desired 3,6-di[(5-phenylmethoxypyridin-2-yl)metbylidene] piperaztne-2,5-dione (Compound 10). mp: 283-2B°C. lHNMR (400MHz, DMSO): δ5.145 (s, 4H), δ6.780 (s, 2H), δ7240- δ7394 (m, 14H, aromatic), δ8.381 (s, 2H), δ3 0.145 (s, 1H), and δ12.58 (s, 1H). Example 11; Synthesis of 3-[(5-phenylrnethoxypyridin-2-yl)methyIiden6]-6-(2-oxo- 3-indalylidenepiperaziae-2,5-dione (Compound 11). Compound A (2.8 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 1.5g of isatine end 4 equivalent of triethylamine. The solution was refluxed at 330°C for 2 hr and cooled at ice beth to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3.04 g (87%) of the desired 3-[(5-phenylmethoxypyridin-2-yl)methylidene]-6-(2-oxo-3-indolylidenepiperazine-2,5-dione (Compound 11). mp:>300°C. Example 12: Synthesis of l-acetyl-3-[(5-benzyoxypyridin-2-yl)ineihyl]piperazihe'2,5-dione (Compound 12). A suspension of 3.51 g of l,4-diacethyl-piperazine-2,5-diono and excess of zinc powder in a mixture of 100 mL of acetic acid and 10 mL of water was stirred and refluxed for 5-10 minutes and cooled. The mixture was filtered. The solid thus obtained was collected and washed with water to give 2.0 g of the desired l-acetyl-3-[(5-benzyoxypyridin-2-yl)rnethyl]piperazine-2,5-dionc (Compound 12). mp:215-216°C. Example 13: Synthesis of 3,6-di[(5-benzyoxypyridm-2-yl)methyl]pipenmne-2,5-dione (Compound 13). A suspension of 3,6-di[(5-benzyoxypyridin-2-yl)methylidenelpiperazine-2,5-dione (0.2 g) and excess of zinc powdeT in a mixture of 10 mL of acetic acid and 10 mL of water -was-Btirred-aBd refluxed-for 5-10-minutes -and- filtered while-hot Water was -added to dissolve zinc acetate. The filtrate was concentrated and filtered. The solid thus obtained was collected and washed with water to give 80 mg (40%) of the desired 3,6~di[(5-benzyoxypyiidin-2-yl)metbyl]piperazine-2,5-dione (Compound 13). mp: 228-231°C. Example 14: Synthesis of3-[(5-acetoxypyridin-2-yl)rnethylidene]-6-(benzylnicthylidene) piperazine-2,5-dione (Compound 14). 34(5-tenzyloxypyridin-2-yl)methlidene]-6-(benzylmethylidene)piperazine2,5-dionc (Compound 1,0.5 g, 126 mmol) and NaOH (0.5 g, 12.5 mmol) -were dissolved in 100 mL of methanol. The mixture was hydrogenated with 0.5 g palladium/charcoal under 1 atmospheric pressure. After completing the reaction as monitored by TLC, the catalyst was removed by filtration and the filtrate was evaporated in vacuo to produce a reside. The residue was added with 50 mL water and the obtained aqueous solution was adjusted to pH-7. A precipitated was formed and collected to obtain a 0.27 g product of 3-[(5-hydroxypyridm-2-yl)methylidene]-6-(hcnzylmethylidene)piperazinc-2,5-dione (Compound B) (70 % yield). 1HNMR (400MHz, CDCla): δ6.758 (s, 1H), δ7.087 (s, 1H), δ7.290-δ7.580 (m, 7H, aromatic), δ8.328 (s, 1H), and δ12.289 (s, 1H). A solution of compound B (0.05 g, 0.16 mmole) in acetic anhydride (50 ;mL) was refluxed at 150°C for 24 hrs. The unreacted acetic anhydride and produced acetic acid were removed in vacuo to obtain a residue. The residue was chromatographied using silica gel column with a developing solvent (CH2Cl2 : MeOH = 9 :1) to give 0.051 g (90%) of Compound 14 as a mixture of isomers. The mixture was predominately the ZZ isomer. 1HNMR (400MHz, CDC13): δ2377 (s, 3H), δ6.786 (s, 1H), δ7.107 (a, 1H), δ7.368-δ.496 (m, 7H, aromatic), δ8-224 (s, 1H), and δ12.498 (s, 1H). Example 15: Synthesis of 3-[(5-benzoyloxypyridin-2-yl)methylidene]-6-(benzylmethylidene)piperazine-2,5-dione (Compound 15). A reaction mixture containing compound B (0.05 g, 0.16 mmole; obtained from Example 14), benzoyl chloride (15 ml, 0.16 mmole) and 50 mL of chloroform was heated to 150°C for 2hr Chloroform was removed in vacuo to produce a residue.The residue was chromatographied using silica gel column with a developing solvent (CH2Cl2) to give 0.007 g (10%) of Compound 15. 1HNMR (400MHz, CDC13): δ6.786 (B, 1H), δ7.107 (s, 1H), δ7.36S~δ8.496 (m, 13H, aromatic), and δ8.223 (s, 1H). Example 16; Synthesis of 3-[(5-(4-toluenesuIfonyl)pyridin-2-yl)methylidene]-6-(beirzylmetbylidene) piperazine-2,5-dione (Compound 16). A reaction mixture of compound B (0.05 g, 0.16 mmole; obtained from Example 14), toluenesulfony] chloride (0.03 g, 0,16 mmole), and 50 mL of toluene was heated to 250°C for 2 hr. Toluene was removed in vacuo to produce a residue. The residue was chromatographied using silica gel column with a developing solvent (CHaCy to give 0-007 g (10%) of Compound 16. 1HNMR (400MHz, CDC13): δ2.503 (s, 3H), δ6.751 (s, 1H), δ7.102 (s, 1H), δ7.343-δ8.159 (m, 12H, aromatic), δ8223 (s, 1H), and δ12315 (s, 1H). Example 17; Synthesis of 3-[(5-(4-chlbrophenylcarbarnic)pyridin-2-yl)methyliderie]-6-(benzylmethylidene) piperazinc-2,5-dione (Compound 17). A reaction mixture of compound B (0.05 g, 0.16 mmole; obtained from Example 14), 4-chlorophenylisocyanate (0.024 g, 0.16 mmole), and 50 mL of chloroform was heated to 100°C for 24 hr. Chloroform was removed in produce a residue. The residue was chromatographied using silica gel column with a developing solvent (CH2Cl2) to give 0.0lg (15%) of Compound 17. Example 18: Screening for anti-tumor activities (NCI cell lines). The cytotoxic activities of a number of piperazinedione compounds were measured against a panel of 60 different NCI human tumor cell lines. All test compounds were found to be active. The least potent compound exhibited GI50 values Example 19; Screening for anti-tumor activities (a prostate cell line). The cytotoxic activities of a number of piperazinedione compounds and taxol (a well-known anti-tumor agent) were tested on PC-3 cells. Cells were incubated in the presence of each compound in a serum-free medium for 24 hr. The cytotoxic activities were determined by the MTT assay. All test compounds are active. Unexpectively, the most potent piperazinedione compound has an EC50 value around 0.3 microM, >30 times more potent than taxbl. Example 20: In vitro assay (inhibition of G2/M progression of the cell cycle). PC-3 cells were incubated in the presence of a piperazinedione compound in a serum-free medium and harvested, fixed, and stained with propidlum iodide at the 6, 12, 18, and 24 hr, respectively. The stage of cell cycles was determined based on flow cytometric measurements. The test compound induced an arrest of the cell cycle as entranced by a large number of cells at G2M phase. In addition, a piperazinedione compound had a marked effect on the regulation of Ras activity Example 21: In vitro assay (disturbance of tubulin/microtubulin assembly). 1 _ 'Tubulin/microtubulin was incubated in the presence of a piperazinedione compound at different concentrations in a solution (0.1 M MES, 1 mM EGTA, 0.5 mM MgClj. 0.1 mM EDTA, and 2.5 M glycerol) at 37DC. Then, GTP was added to induce polymerization of tubulin/microtubulin. Optical density (OD) was measured at 350 ran at various time points to determine the degree of the polymerization. The test compound inhibited the polymerization at 10-6 - 10-5 M. Example 22: In vivo assay (inhibition of tumor enlargement) SCID mice, subcutaneously injected into PC-3 cells, developed a tumor more than 800 mm3 in volume. A piperazinedione compound significantly diminished the tumor volume after a 14-28 days treatment. Example 23: In vivo assay (regulation of angiogenesis activity) After subcutaneous incubation of a bFGF or VEGF-containing matrigcl plug (0.5 mL/20g mouse) for 6 days, a significant angiogenic effect was detected in the plug. Intraperitoneal injection of a piperazinedione compound almost completely diminished the angiogenic effect OTHER EMBODIMENTS All of the features disclosed in this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features. From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. For example, compounds structurally analogous the piperazinedlone compounds of this invention also can be made, screened for their anti-tumor activities, and used to practice this invention. Thus, other embodiments are also within the claims. WE CLAIM: Piperazinedione compounds of the formula: (Formula Removed) wherein A is C(RaRb); Z is R30-(Ar)-B, in which B is C(RC); Ar is pyridyl linked to B at position 2; R3 is H, alkyl substituted with aryl or aryl; in which aryl is unsubstituted or substituted with one or more substitutents selected from the group consisting of halogen, hydroxyl, amino, alkylamino, arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbamido, carbamoyl, carboxyl, thioureido, thiocyanato, sulfonamide, C~C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy, and aryl; each of Ri and R2, independently, is H, or C(O)Rd; and one of Ra and Rb is thienyl, furyl, pyridinyl, indolyl, 2-oxo-indolyl, aryl, alkyl or alkyl substituted with aryl and each of the other of Ra and Rb, and Rc and Rd, independently is H, alkyl or aryl; in which alkyl and aryl are unsubstituted or substituted with one or more substitutents selected from the group consisting of halogen, hydroxyl, amino, alkylamino, arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbamido, carbamoyl, carboxyl, thioureido, thiocyanato, sulfonamide, C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy and aryl. 2. The compound as claimed in claim 1, wherein Rc is H. 3. The compound as claimed in claim 2, wherein R3O is linked to position 5 of pyridyl. 4. The compound as claimed in claim 3, wherein R3O is arylalkoxy. 5. The compound as claimed in claim 4, wherein both Ri and R2 are H. 6. The compound as claimed in claim 5, wherein one of Ra and Rb is aryl or thienyl, furyl, pyridinyl, indolyl or 2-oxo-indolyl and the other of Ra and Rb is H. 7. The compound as claimed in claim 6, wherein R3O is benzyloxy. 8. The compound as claimed in claim 1, wherein R3O is arylalkoxy. 9. The compound as claimed in claim 1, wherein both Ri and R2 are H. 10. The compound as claimed in claim 9, wherein Rc is H. 11. The compound as claimed in claim 1, wherein one of Ra and Rb is aryl or thienyl, furyl, pyridinyl, indolyl or 2-oxo-indolyl and the other of Ra and Rb is H. 12. The compound as claimed in claim 11, wherein Rc is H. 13. The compound as claimed in claim 12, wherein R3O is arylalkoxy linked to position 5 of pyridyl. 14. The compound as claimed in claim 1, wherein the compound is (Formula Removed) wherein Bn is benzyl. 15. The compound as claimed in claim 14, wherein the compound is (Formula Removed) 16. The compound as claimed in claim 14, wherein the compound is (Formula Removed)

Full Text

BACKGROUND
The treatment of tumor can be approached by several modes of therapy, including surgery, radiation, chemotherapy, or any combination of any of these treatments. Among them, chemotherapy is indispensable.for inoperable or metastatic forms of cancer. Considering the diversity of tumors in terms of cell type, morphology, growth rate, and other cellular characteristics, the U.S. National Cancer Institute (NCI) has developed a "disease-oriented" approach to anti-tumor activity screening. Boyd, M.R (1989) In Principle of Practice of Oncology Devita, J.T., Hellman, S., and Rosenberg, S.A. (Eds.) Vol. 3, PPO Update, No. 10. This in vitro screening system is based on human tumor cell line panels consisting of approximately 60 cell lines of major human tumors (e.g., leukemia, lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer, or breast cancer), and serves as a tool for identifying compounds that possess anti-tumor activities.
Of particular interest are the anti-tumor compounds that function via one or more of the following four mechanisms: (1) inhibiting G3/M progression of the cell cycle, which might eventually induce the apoptosis in tumor cells (Yeung et ah (1999) Biochem. Biophys. Res. Com. 263:398-404); (2) disturbing tubulin asserobly/dissembly, which may inhibit the cell mitosis and induce the cell apoptosis (Panda et ah (1997) Proc. Natl Acad, Sci. USA 94:10560-10564); (3) inhibiting endothelial cell proliferation and angiogenesis effect (Witto et ah (1998) Cancer Metastasis Rev. 17: 155-161; Prewett et ah (1999) Cancer Res. 59: 5209-5218); or (4) regulating Ras protein-dependent signal transduction pathway (Hemandez-AJcoceba ef ah (2000) CellMol Life Sci. 57: 65-76; Buolamwini (.1999) Cur. Opin. Clie. Biol. 3; 500-509).
SUMMARY
This invention is based in part on the discovery that piperazinedione compounds have anti-tumor activities, identified by NCI screening system, and function via one OT more of the above-mentioned four mechanisms.
An aspect of the present invention relates to piperazinedione compounds of formula:
(Formula Removed)
Each of and , independently, is a single bond or a double bond; A is H or CHCR'Rb) • when is a single bond, or C(R R1') when = is a double bond. Z is R3O-(Ar)-B, in which B is OH(R') when is a single bond, or C(R) when = is a double bond; Ar is heteroaryl; Rj isH, alkyl, aryl, heteroaryl, C(0)R Referring to the above formula, a.subset of the piperazinedione compounds of this invention is featured by that both = and = are double bonds. In these compounds, Ar is pyridyl linked to B at position 2, Rc is H, R3O is arylalkoxy linked to position 5 of pyridyl, both R1 and R2 are H, one of Ra and Rb is aryl or heteroaryl, and the other of R' and Rb is H. Another subset of the piperazinedione compounds of this invention is featured by that both ==and : are single bonds. In these compounds, Ar is pyridyl linked to B at position 2, Rc is H, R3O is arylalkoxy linked to position 5 of pyridyl, bothR1and R2 are H, one of R"
andb is H, aryl, orheteroaryl,-fin.d the other of R'and Rb is H.
Alkyl, aryl, heteroaryl, cyclyl, and heterocyclyl mentioned herein include both substituted and unsubstituted moieties, The term "substituted" refers to one or more substituents (which may be the same or different), each replacing a hydrogen atom. Examples of substituents include, but are not limited to, halogen, hydroxyl, amino, alkylamino, arylamino, dialkylamino, diaryl amino, cyano, nitro, mercapto, carbonyl, carbamido, carbamyl, carboxyl, thioureido, thjocyanalo, sulfoamido, C1-C6 alkyl, C1-C6 alkenyl, C1-C6alkoxy, aryl, heteroaryl, cyclyl, heterocyclyl, wherein alkyl, alkenyl, alkoxy, aryl, heteroaryl cyclyl, and heterocyclyl are optionally substituted with C1-C6 alkyl, aryl, heteroaryl, halogen, hydroxyl, amino, mercapto, cyano, or nitro. The term "aryl" refers to a hydrocarbon ring system having at least one aromatic ring. Examples of aryl moieties
include, but are not limited to, phenyl, naphthyl, and pyrenyl. The term "hetcroaryr refers to a hydrocarbon ring system having at least one aromatic ring which contains at least one heteroatom such as O, N, or S. Examples of heteroaryl moieties include, but are not limited to, fury!, fluorenyl, pyrrolyl, thienyl, oxazolyl, Imidazolyl, thiazolyl, pyridinyl, pyrimidinyl, quinazolinyl, and indolyl.
Another aspect of the present invention relates to a pharmaceutical composition that contains a pharmaceutically acceptable carrier and an effective amount of at least one of the piperazinedione compounds described above.
A further aspect of this invention relates to a method for treating tumor (e.g., leukemia, lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer, or breast cancer). The method includes administering to a subject in need thereof an effective amount of the piperazinedione compound having the formula:
(Formula Removed)
Each of = and = , independently, is a single bond or a double bond; A isH or GH(RaRb) when = is a single bond, or C(RaRb) when = is a double bond; Z is CH(RcRd) when = is a single bond, or C(RcRb) when = is a double bond; each ofR1and R2, independently, is H, C(0)Re, C(0)OR", C(O)NR.tR1, or SO2R'; and each of R', Rb, Rc, Rd, R6, and Rr, independently, is H, alkyl, aryl, heteroaryl, cyclyl, or heterocyclyl, provided that one of Rc and R1 is aryl or heteroaryl. If == is a double bond, ==== is a single bond, and one of Rc-and Rd is H, then the other of Rc and Rd is heteroaryl. Optionally, R' and Rh taken together are cyclyl or heterocyclyl; and, also optionally, Rt and R' or Rj and R* taken together are cyclyl or heterocyclyl.
Referring to the above formula, a subset of the just-described piperazinedione compounds is featured by that both = and = are double bonds. In these compounds, one of Rc andRd is 2=pyridy the-othei of Rc and.Rd.is H,.bothR1.and R2 areH, one of Ra and Rb is aryl or heteroaryl, and the other of R' and Rb is H. The 2-pyridyl can be further substituted with 5-arylalkoxy. Another subset of the piperazinedione compounds is featured by that both = and = are single bonds. In these compounds, one of R° and R is 2-
pyridyl, the other of Rc and Rd is H, both R1, and Ra are H, one of Ra and Rb Is H, aryl, or heteroaryl, and the other of Ra and Rb is H.
Seven exemplary piperazinedione compounds are 3-[(5-benzyoxypyrldin-2-yl)methylidene]-6-phenylmerbylidenepiprazine-2,5-dione, 3-[(5-benzyoxypyridin-2-yl)melhylidene]-6-p-bydroxyphenylmethyIidenepiperazine-2,5-djone, 3-[(5-benzyoxypyridm-2-yl)methylidene]-6-p-fluorophenylmethylidenepiperazie-2,5dione,3-[(5-benzyoxypyridin-2-yl)methyl5dene]-6-p-chlorophenylmethylidenepiperazine-2,5-dione, 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-phenylinetboxy
phenylmethylidenepiperazine-2,5-dione, 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-[(thien-2-yl)methylidene3piperazine-2,5-dione, and 3,6-di[(5-pheny]methoxypyridin-2-yl)rnethyI]piperazine-2,5-o,ione. Their structures are shown below:
(Formula Removed)
The piperazinedione compounds described above include the compounds themselves, as well as their salts and their prodrugs, if applicable. Such salts, for example, can be formed
between a positively charged substituent (e.g., amino) on a piperazinedione compound and an anion, Suitable anions include, but are not limited to, chloride, bromide, iodide, sulfate, nitrate, phosphate, citrate, methanesulfbnate, trifluoroacetate, and acetate. Likewise, a negatively charged substituent (e.g., carboxylate) on a piperazinedione compound can form a salt with a cation. Suitable cations include, but are not limited to, sodium ion, potassium ion, magnesium ion, calcium ion, and an ammonium cation such as teteramethylammonium ion. Examples of prodrugs include esters and other phaimaceutically acceptable derivatives, which, upon administration to a subject, are capable of providing piperazinedione compounds described above.
Also within the scope of this invention are a composition containing one or more of the piperazinedione compounds described above for use in treating tumor, and the use of such a composition for the manufacture of a medicament for the just-described use.
Other features or advantages of the present invention will be apparent from the following detailed description of several embodiments, and also from the appending claims.
DETAILED DESCRIPTION
The piperazinedione compounds described above can be prepared by methods well known in the art, as well as by the synthetic routes disclosed herein. For example, one can react a piperazine-2,5-dione compound with a heteroaryl formaldehyde to produce an intermediate heteroaryl-methyJidene-pipera2ine-2,5-dione. The intermediate can then bo reduced to heteroaryl-methyl'piperazine-2,5-dione (a compound of this invention), or reacted with a ketone or another formaldehyde, followed by a base treatment, to produce a mixture of piperazinedione isomers, which are cis- or trans- or E- or Z- double bond isomeric forms, The desired isomeric product can be separated from others by high pressure liquid chromatography (HPLC). If preferred, proper functional groups can be introduced into the heteroaryl ring by further modifications. Alternatively, a desired reduced product can be obtained by reacting the product with a reducing agent
Shown below is a scheme that depicts the synthesis of seventeen piperazinedione compounds.
(Formula Removed)
Details of synthesis of Compounds 1-17 are described in Examples 1-17, respectively. To prepare other piperazincdione compounds, the pyridinyl (shown in the above scheme) can be replaced by an aryl or another heteioaryl (e.g., furyl, pyrrolyl, imidazolyl, pyrimidinyl, or indolyl), and one of the two acetyl groups (Ac) on the piperazincdione ring (also shown in the above scheme) can be replaced by another substituent (e.g., carbonyl, carbamido, carbamyl, or carboxyl).
Note that the piperazinedionc compounds contain at least two double bonds, and may further contain one or more asymmetric centers. Thus, they can occur as racemares and racemic mixtures,single enantiomers, individual diastercomers, diastereomcric mixtures, and cis- or trans- or E- or Z- double bond isomeric forms. All such isomeric forms arc contemplated.
Also within the scope of this invention is a pharmaceutical composition that contains an effective amount of at least one piperazinedione compound of the present invention and a pharmaceutically acceptable carrier. Further, this invention covers a method of administering an effective amount of one or more of the piperazinedione compounds described in the "Summary" section above to a subject in need of tumor treatment The piperazinedione compounds can function via one or more of the above described action mechanisms, or via any other mechanism. "An effective amount" refers to the amount of the compound which is required to confer a therapeutic effect on the treated subject. The interrelationship of dosages for animals and humans (based on milligrams per meter squared of body surface) is described in Freireich ei ah, (1966) Cancer Chemother Rep 50:219. Body surface area may be approximately determined from height and weight of the patient. See, e.g., Scientific Tables, Geigy Pharmaceuticals, Ardley, N.Y., 1970, 537. An effective amount of the piperazinedione compounds can range from about 0.1 mg/Kg to about 50 mg/Kg. Effective doses will also vary, as recognized by those skilled in the art,idepending on the types of tumors treated, route of administration, excipient usage, and the possibility of co-usage with other therapeutic treatments such as use of other anti-tumor agents or radiation therapy.
To practice the method of the present invention, a piperazinedione compound-containing composition can be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. The term "parenteral" as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intraarticular, intraarterial, intrasynovial, intrasternal, intrathecal, intraleslonal and intracranial injection or infusion techniques.
A sterile injectable composition, for example, a sterile injectable aqueous or oleaginous suspension, can be formulated according to techniques known in the art using suitable dispersing or wetting agents (such as, for example, Tween 80) and suspending agents. The sterile injectable preparation can also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that can be employed are mannitol, water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium
(e.g., synthetic mono- or diglycerides). Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmHceutjcally-acceptable oils, such as olive oil or castor oil, especially in their polyaxyethylatod versions. These oil solutions or suspensions can also contain a long-chain alcohol diluent or dispersant, or carboxymethyl cellulose or similar dispersing agents. Other commonly used surfactants such as Tweens or Spans or other similar emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceuticaljy acceptable solid, liquid, or other dosage farms can also be used for the purposes of formulation.
A composition for oral administration can be any orally acceptable dosage form including, but not limited to, capsules, tablets, emulsions and aqueous suspensions, dispersions and solutions. In the case of tablets for oral use, carriers which are commonly used include lactose and core starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried corn starch. "When aqueous suspensions or emulsions arc administered orally, the active ingredient can be suspended or dissolved in an oily phase combined with emulsifying or suspending agents. If desired, certain sweetening, flavoring, or coloring agents can be added. A nasal aerosol or inhalation composition can be prepared according to techniques well-known in the art of pharmaceutical formulation and can be prepared na solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbona, andVor other solubilizing or dispersing agents known in the art A piperazinedione compound-containing composition can also be administered in the form of suppositories for rectal administration.
The carrier in the pharmaceutical composition must be "acceptable" in the sense of being compatible with the active ingredient of the formulation (and preferably, capable of stabilizing it) and not deleterious to the subject to be treated. For example, solubilizing agents such as cyclodextrins, which form specific, more soluble complexes with the piperazinedione compounds, or one or more solubilizing agents, can be utilized as pharmaceuticalexcipientsfor delivery of the piperazinedione compounds. Examples of other carriers include colloidal silicon dioxide, magnesium stearate, cellulose, sodium lauryl sulfate, and D&C Yellow # 10.
The piperazinedione compounds can be preliminarily screened for their efficacy in treating cancer by one or more of the following in vitro assays,
One assay is based on the NCI screening system, which consists of approximately 60 cell lines of major human tumors. See Monks, et al. (1991) JNCl 7. Natl Cancer Insz. 83: 757-766; Alley, et al. (1988) Cancer Res. 48: 589-601; Shoemaker, et al. (1988) Frog. Clin Biol Res. 276:265-286; and Stinson, et al. (1989) Proc Am. Assoc. Cancer Res. 30: 613. Briefly, a cell suspension that is diluted according to the particular cell type and the expected target cell density (5,000-40,000 cells per well based on cell growth characteristics) is added (100 µL) into a 96-well microliter plate. A pre-incubation is preformed at 37° C for 24 hr. Dilutions at twice of an intended lest concentration are added at time zero in 100 µL aliquots to each well of the microliter plate. Usually, a test compound is evaluated at five 10-fold dilutions. In a routine testing, the highest concentration of the test compound is 10-4 M. Incubations are performed for 48 hr in 5% CO2 atmosphere and 100% humidity. The cells are assayed by using the sulforhodamine B assay described by Rubinstein, et al'. (1990, JNCl J. Natl Cancer Inst. 82:1113-1118) and Skehan, et al. (1990, JNCl, J. Natl Cancer Inst 82: 1107-1112). A plate reader is used to read the optical densities and a microcomputer processes the optical densities into the special concentration parameters. The NCI has renamed an IC50 value, the concentration that causes 50% growth inhibition, a GI50 value to emphasize the correction for the cell counted at time zero; thus, the GI50 measures the growth inhibitory power of the test compound. See Boyd, et al. (1992) In Cytotoxic Anticancer Drugs: Models and Concepts for Drug Discovery and Development; VlEriote, F.A.; Corbett, T.H.; Baker, L.H. (Eds.); Kluwer Academic: Hingham, MA, pp 11-34
hvanother assay, a piperazinedione compound is tested for its cytotoxicity on PC-3 cells (a prostate cancer cell line). More specifjcally, cells are incubated with a test compound in a serum-free medium for 24 hr. The cytotoxic effect can be determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method described in Boyd (In Principle of Practice of Oncology Devita, J.T., Hellman, S., and Rosenberg, S.A. —(Eds.)-Vol. -3-,PPOUpdate,-No-l-Q, 1989).-
Another in vitro assay can be used to evaluate the efficiency of a piperazinedione compound in arresting the cell cycle progression. More specifically, a test piperazinedione compound is added to PC-3 cells in a concentration-dependent manner using propidium
iodide-stained flow cytometric assessment The cell population of sub-Go/Gi, Gc/Gj. S, and G2/M phase is then determined. In addition, the effect of a piperazinedione compound on fee Ras activity can be examined to determine its regulation of Ras protein-dependent signal transduction pathway.
The anti-tumor activity of a piperazinedione compound can be further assessed by an in vivo animal model. Using SCID mice as the model, PC-3 cells are subcutaneously injected into the mice to develop a prostate tumor. The anti-tumor activity of* piperazinedione compound is determined after treatment. Additionally, the anti-tumor activity of a piperazinedione compound can also be evaluated using in vivo anti-angiogenesis testing. For example, nude mice can be used to test the effect of a piperazinediooe compound on bFGP-induced angiogenesi9. A matrigel with bFGF or vscular endothelial growth factor (VEGF) is subcutaneously injected into a mouse with concurrent intraperitoneal administration of a piperazinedione compound. After several days of incubation, the matrigel is cut down for examination of angiogeneais.
Without further elaboration, it is believed that the above description has adequately enabled the present invention. The following specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. All of the publications cited herein are hereby incorporated by reference in their entirety.
Example 1: Synthesis of 3-[(5-benzyoxypyridin-2-yl)meihylidene]-6-phenylmethyIidene piperazine-2,5-dione (Compound 1).
l,4-Diacetyl-piperazine-2,5-dione (8.6 g) was added to a solution of 5-berizyoxypyridin-2-yl-forrnaldeb.yde (4.0 g) in 5.6 mL of triethylamine and 40 mL of dimethylformamide. The mixture was stirred at room temperature for 16 hr and then cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 5.4 g (77%) of l-acetyl-3-[(5-benzyoxypyridin-2-yl)methylidene]piperazme-2,5-dione-(CompoundA.). mp: 189-191°C.
1HNMR (400MHz, DMSO): δ2.52 (s, 3H), 54.54 (s, 3H), S4.33 (a, 2H), 55.25 (s, 2H), 56.85 (s. 1H), 57.384-67.488 (m, 5H, aromatic), δ7.499 (d, J-8.8, 1H), 57.689 (d, J=8.8, 1H), 68.533 (s, 1H)} and 512.147 (s, 1H).
Compound A (3.51 g) was added to a 40 mL of dimethylfonnamide solution containing equal molar of benaaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 60°C for 16 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 33 g (83%) of the desired produrt 3-[(5-ben2yoxypyridin-2-yl)methylidene]-6-phenylmethylidenepiperazlnc-2,5-dione (Compound 1) as a mixture of isomers. The mixture was predominately the ZZ and EZ isomers.
mp: 223-22S°C,
1HNMR (400MHZ, DMSO): 65.243 (a, 2H), 56,695 (s, 1H), 56.812 (s, 1H). 57.346-57.634 (m, 12H, aromatic), δ8.528 (s, 1H), 510.245 (s, 1H), and 512.289 (s, 1H).
Example 2: Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-hydroxyphenyI methylidenepiperazine-2,5-dione (Compound 2).
Compound A (3.51 g), obtained from Example 1, was added to a 40 mL of dunethylforrnamide solution containing 1.5 g of 4-hydroxybenzaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 130°C for 16 hr and cooled at icebath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3.3 g (83%) of the desired 3-[(5-benzyoxypyridra-2-yl) methylidene]-6-p-hydroxyphenylmethylidenepiperazine-2,5-dione (Compound 2).
mp: 260-263°C.
1HNMR (400MHz, DMSO): δ5.244 (s, 2H), 16.669 (s, 1H), 56.753 (s, 1H), 86.79B (a, 1H, aromatic), δ6.819 (s, 1H, aromatic), S7.347-87.647 (m, 9H, aromatic), δ9.821 (s, 1H), 510.064 (s, 1H), and 812.216 (s, 1H).
-Example 3 :Synthesis-of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-methoxyphenyl methy)idenepiperazine-2,5-dione (Compound 3).
Compound A (3.51 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 1.4 g of 4-methoxybenzaldebyde and 4 equivalents
of triethylamine. The solution was reluxed at 130°C for 16 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3.3 g (83%) of the desired 3-[(5-benzyoxypyridin-2-yl) roethylidene]-6-methoxyphenylmethylidenepipera2iae-2,5-dione (Compound 3).
rop: 238-240°C.
1HNMR (400MHz, DMSO): S5.244 (s, 2H), 56.669 (s, 1H), 66.753 (a, 1H), 56.79S (s, 1H, aromatic), δ6,819 (s, 1H, aromatic), δ7.347~S7.647 (m, 9H, aromatic), δ9.821 (s, 1H), 510.064 (s, 1H), and 512.216 (s, IH).
Example 4: Synthesis of 3-[(5-benzyoxypyTidb-2-yl)methylidene]-6-p-fluorophenyl methylidenepipera2ine-2,5-dione (Compound 4).
Compound A (3.51 g), obtained from Example 1, was added to a 40 mL of dimethylfonnamide solution containing 1.3 g of 4-fluoro benzaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 130CC for 16 hr and cooled at ice bafh to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3,12 g (75%) of the desired 3-[(5-benryovypyrIdin-2-yl)methylidene] -6-p-fluorophenylmethylidenepiperazine-2,5-dJone (Compound 4).
rap: 242-244°C,
1HNMR (400MHz, DMSO); 65.237 (s, 2H), 86:688 (s, 1H), 66.794 (s, 1H), 57.209-S7.624 (m, 1 1H, aromatic), 68.520 (s, 1H), 510.348 (s, 1H), and 512.279 (s, IH).
Example 5: Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-p-chlorophenyl methylidenepiperazinc-2,5dione (Compound 5).
Compound A (3.51 g), obtained from Example 1, was added to a40 mL of dhnethylformamide solution containing 1.3 g of 4-chlorobenzaldehyde and 4 equivalents of triethylamine. The solution was refluxed at 130°C for 16 hr and cooled at ice bath to produce a yellow precipitate. Then the precipitate was collected and washed with ethyl acetate to give 3-45 g (80%) of the desired 3-[(5-benzyoxypyridin-2-yl)methylidcaoe]-6-p-chlorophenylmethylidenepiperazine-2,5-dione (Compound 5).
rap: 250-251oC.
Example 6: Synthesis of 3-[(5-ben2yoxypyridin-2-yl)methylidene]-6-p-benzyoxyphenylmethylidene piperazine-2,5-dione (Compound 6).
Compound A (3.51.g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 1.45 g of 4-benzyoxybenzaIdehyde and 4 equivalents of triethylamine. The solution was refluxed at 130°C for 16 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected, washed with ethyl acetate, and recrystallized from dimethylformamide to give 3.45 g (80%) of the desired 3-[(5-benzyoxypyridin-2-yl)methylideneJ-6-p-ben2yoxyphenylmethylidencpiperazine'2,5-dione (Compound 6).
mp: 253-255°C.
1HNMR (400MHz, DMSO): δ5.142 (s, 2H), 55.235 (s, 2H). 56.672 (s, 1H), 56.777 (s, 1H), S7.041~57.639 (m, 16H, aromatic), δ?_520 (s, 1H), 510.180 (s, 1H), and 512.235 (a, IH).
Example 7; Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylidene]-6-[(furan-2-yl) mcdvylidene]piperazine-2,5-dione (Compound 7).
Compound A (2.8 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 2 mL of furfural and 4 equivalents of triethylamine. The solution was refluxed at 60°C for 48 hr and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected, washed with ethyl acetate, and recrystallized from dimethylformamide to give 2,5 g (80%) of the desired 3-[(5-benzyoxypyridin-2-yl)methylidenc)-6-[(furan-2-yl)mcthylidene]piperazJne>2,5-dione (Compound 7). mp: 256-2S7°C.
JHNMR (400MHz, DMSO): 65.245 (s, 2H), 56.656 (d, J=1.6, 1H), 86.664 (d, JM.6, 1H), 56.685 (s, 1H), 56.720 (s, 1H), 57.349-57.942 (m, 8H, aromatic), δ8.527 (s, 1H), 59.515 (s, 1H), and 512.312 (s, IH).
Example 8-Synthesis of 3-[(5-benzyoxypyridin-2-yl)methylicene]-6-[(thien-2-yl)
methylidene]piperazine-2,5-dione (Compound 8).
Compound A (2.8 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 2 mL of thiophene-2-carbaldehyde and 4 equivalents
of triethy]amine. The solution was refluxed at 60°C for 2 days and cooled at ice bath to produce a yellow precipitate. The precipitate -was then collected, a -washed with ethyl acetate, and recrystallized from dimethyiformamide to give 1.9 g (59%) of the desired 3-[(5-
benzyoxypyridin-2-yl)methylidene]-6-[(thiophene-2-yl)methylidene]piperazine-2,5-dionc (Compound 8).
rap: 215-217°C.
1HNMR. (400MHz, DMSO): δ5.245 (s, 2H), 86.716 (s, 1H), 56.974 (s, 1H), 57.186 (a,
1H), 57.384-57.746 (m, 9H, aromatic), δ8.525 (s, 1H), 59.753 (s, 1H), and 512.288 (s, 1H).
Example 9: Synthesis of 3-[(5-benzyloxypyridin-2-yl)methylidene]-6-[(2-pyridinyl) methylidene]piperazine-2,5-dione (Compound 9).
Compound A (2.8 g). obtained from Example 1, was added to a 40 mL of dimethyiformamide solution containing 2 mL of pyridine-2-carbaIdehyde and 4 equivalents of triethylamine. The solution was refluxed at 60°C for 2 days and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected, a washed with ethyl acetate, and recryslallized from dimethyiformamide to give 2.7 g (85%) of the; desired 3-[(5-benzyloxypyridin-2-yl)methyIJdene]-6-[(2-pyridinyl)methylidene]pipera2ine-2,5-dione (Compound 9).
mp: 248-250°C.
1HNMR (400MHZ, DMSO): δ5.246 (s, 2H), 56.709 (s, 1H). 56.788 (s, 1H), δ7.349-δ7.661(m,8H,aromatic),δ7,923 (d,J=81H,aromatic), δ8.473(d,J=3.6,1H.) 58.533 (d, J=2.8,1H), 58.680 (d, J=2,1H), SI 0.667 (s, 1H), and 512.324 (s, 1H).
Example 10: Synthesis of 3,6-di[(5-phenylmethoxypyridin-2-yl)methylidenc}pipera2ine -2,5-dione (Compound 10).
Compound A (0.31 g), obtained from Example 1, was added to a 40 mL of dimethyiformamide solution containing equal molar of 5-benzyoxypyridin-2-yl-formaldehyde and-4-equivalents of triethylamine-The soluation was rofluxed at 130°C
overnight and cooled at ice bath to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 0.36 g (80%) of the desired 3,6-di[(5-phenylmethoxypyridin-2-yl)metbylidene] piperaztne-2,5-dione (Compound 10).
mp: 283-2B°C.
lHNMR (400MHz, DMSO): δ5.145 (s, 4H), δ6.780 (s, 2H), δ7240- δ7394 (m, 14H, aromatic), δ8.381 (s, 2H), δ3 0.145 (s, 1H), and δ12.58 (s, 1H).
Example 11; Synthesis of 3-[(5-phenylrnethoxypyridin-2-yl)methyIiden6]-6-(2-oxo- 3-indalylidenepiperaziae-2,5-dione (Compound 11).
Compound A (2.8 g), obtained from Example 1, was added to a 40 mL of dimethylformamide solution containing 1.5g of isatine end 4 equivalent of triethylamine. The solution was refluxed at 330°C for 2 hr and cooled at ice beth to produce a yellow precipitate. The precipitate was then collected and washed with ethyl acetate to give 3.04 g (87%) of the desired 3-[(5-phenylmethoxypyridin-2-yl)methylidene]-6-(2-oxo-3-indolylidenepiperazine-2,5-dione (Compound 11).
mp:>300°C.
Example 12: Synthesis of l-acetyl-3-[(5-benzyoxypyridin-2-yl)ineihyl]piperazihe'2,5-dione (Compound 12).
A suspension of 3.51 g of l,4-diacethyl-piperazine-2,5-diono and excess of zinc powder in a mixture of 100 mL of acetic acid and 10 mL of water was stirred and refluxed for 5-10 minutes and cooled. The mixture was filtered. The solid thus obtained was collected and washed with water to give 2.0 g of the desired l-acetyl-3-[(5-benzyoxypyridin-2-yl)rnethyl]piperazine-2,5-dionc (Compound 12).
mp:215-216°C.
Example 13: Synthesis of 3,6-di[(5-benzyoxypyridm-2-yl)methyl]pipenmne-2,5-dione (Compound 13).
A suspension of 3,6-di[(5-benzyoxypyridin-2-yl)methylidenelpiperazine-2,5-dione (0.2 g) and excess of zinc powdeT in a mixture of 10 mL of acetic acid and 10 mL of water -was-Btirred-aBd refluxed-for 5-10-minutes -and- filtered while-hot Water was -added to dissolve zinc acetate. The filtrate was concentrated and filtered. The solid thus obtained was collected and washed with water to give 80 mg (40%) of the desired 3,6~di[(5-benzyoxypyiidin-2-yl)metbyl]piperazine-2,5-dione (Compound 13).
mp: 228-231°C.
Example 14: Synthesis of3-[(5-acetoxypyridin-2-yl)rnethylidene]-6-(benzylnicthylidene) piperazine-2,5-dione (Compound 14).
34(5-tenzyloxypyridin-2-yl)methlidene]-6-(benzylmethylidene)piperazine2,5-dionc (Compound 1,0.5 g, 126 mmol) and NaOH (0.5 g, 12.5 mmol) -were dissolved in 100 mL of methanol. The mixture was hydrogenated with 0.5 g palladium/charcoal under 1 atmospheric pressure. After completing the reaction as monitored by TLC, the catalyst was removed by filtration and the filtrate was evaporated in vacuo to produce a reside. The residue was added with 50 mL water and the obtained aqueous solution was adjusted to pH-7. A precipitated was formed and collected to obtain a 0.27 g product of 3-[(5-hydroxypyridm-2-yl)methylidene]-6-(hcnzylmethylidene)piperazinc-2,5-dione (Compound B) (70 % yield).
1HNMR (400MHz, CDCla): δ6.758 (s, 1H), δ7.087 (s, 1H), δ7.290-δ7.580 (m, 7H, aromatic), δ8.328 (s, 1H), and δ12.289 (s, 1H).
A solution of compound B (0.05 g, 0.16 mmole) in acetic anhydride (50 ;mL) was refluxed at 150°C for 24 hrs. The unreacted acetic anhydride and produced acetic acid were removed in vacuo to obtain a residue. The residue was chromatographied using silica gel column with a developing solvent (CH2Cl2 : MeOH = 9 :1) to give 0.051 g (90%) of Compound 14 as a mixture of isomers. The mixture was predominately the ZZ isomer.
1HNMR (400MHz, CDC13): δ2377 (s, 3H), δ6.786 (s, 1H), δ7.107 (a, 1H), δ7.368-δ.496 (m, 7H, aromatic), δ8-224 (s, 1H), and δ12.498 (s, 1H).
Example 15: Synthesis of 3-[(5-benzoyloxypyridin-2-yl)methylidene]-6-(benzylmethylidene)piperazine-2,5-dione (Compound 15).
A reaction mixture containing compound B (0.05 g, 0.16 mmole; obtained from Example 14), benzoyl chloride (15 ml, 0.16 mmole) and 50 mL of chloroform was heated to 150°C for 2hr Chloroform was removed in vacuo to produce a residue.The residue was
chromatographied using silica gel column with a developing solvent (CH2Cl2) to give 0.007 g (10%) of Compound 15.
1HNMR (400MHz, CDC13): δ6.786 (B, 1H), δ7.107 (s, 1H), δ7.36S~δ8.496 (m, 13H, aromatic), and δ8.223 (s, 1H).
Example 16; Synthesis of 3-[(5-(4-toluenesuIfonyl)pyridin-2-yl)methylidene]-6-(beirzylmetbylidene) piperazine-2,5-dione (Compound 16).
A reaction mixture of compound B (0.05 g, 0.16 mmole; obtained from Example 14), toluenesulfony] chloride (0.03 g, 0,16 mmole), and 50 mL of toluene was heated to 250°C for 2 hr. Toluene was removed in vacuo to produce a residue. The residue was chromatographied using silica gel column with a developing solvent (CHaCy to give 0-007 g (10%) of Compound 16.
1HNMR (400MHz, CDC13): δ2.503 (s, 3H), δ6.751 (s, 1H), δ7.102 (s, 1H), δ7.343-δ8.159 (m, 12H, aromatic), δ8223 (s, 1H), and δ12315 (s, 1H).
Example 17; Synthesis of 3-[(5-(4-chlbrophenylcarbarnic)pyridin-2-yl)methyliderie]-6-(benzylmethylidene) piperazinc-2,5-dione (Compound 17).
A reaction mixture of compound B (0.05 g, 0.16 mmole; obtained from Example 14), 4-chlorophenylisocyanate (0.024 g, 0.16 mmole), and 50 mL of chloroform was heated to 100°C for 24 hr. Chloroform was removed in produce a residue. The residue was chromatographied using silica gel column with a developing solvent (CH2Cl2) to give 0.0lg (15%) of Compound 17.
Example 18: Screening for anti-tumor activities (NCI cell lines).
The cytotoxic activities of a number of piperazinedione compounds were measured against a panel of 60 different NCI human tumor cell lines.
All test compounds were found to be active. The least potent compound exhibited GI50 values Example 19; Screening for anti-tumor activities (a prostate cell line).
The cytotoxic activities of a number of piperazinedione compounds and taxol (a well-known anti-tumor agent) were tested on PC-3 cells. Cells were incubated in the presence of
each compound in a serum-free medium for 24 hr. The cytotoxic activities were determined by the MTT assay. All test compounds are active. Unexpectively, the most potent piperazinedione compound has an EC50 value around 0.3 microM, >30 times more potent than taxbl.
Example 20: In vitro assay (inhibition of G2/M progression of the cell cycle).
PC-3 cells were incubated in the presence of a piperazinedione compound in a serum-free medium and harvested, fixed, and stained with propidlum iodide at the 6*, 12*, 18*, and 24* hr, respectively. The stage of cell cycles was determined based on flow cytometric measurements. The test compound induced an arrest of the cell cycle as entranced by a large number of cells at G2M phase. In addition, a piperazinedione compound had a marked effect on the regulation of Ras activity
Example 21: In vitro assay (disturbance of tubulin/microtubulin assembly). 1 _
'Tubulin/microtubulin was incubated in the presence of a piperazinedione compound at different concentrations in a solution (0.1 M MES, 1 mM EGTA, 0.5 mM MgClj. 0.1 mM EDTA, and 2.5 M glycerol) at 37DC. Then, GTP was added to induce polymerization of tubulin/microtubulin. Optical density (OD) was measured at 350 ran at various time points to determine the degree of the polymerization. The test compound inhibited the polymerization at 10-6 - 10-5 M.
Example 22: In vivo assay (inhibition of tumor enlargement)
SCID mice, subcutaneously injected into PC-3 cells, developed a tumor more than 800 mm3 in volume. A piperazinedione compound significantly diminished the tumor volume after a 14-28 days treatment.
Example 23: In vivo assay (regulation of angiogenesis activity)
After subcutaneous incubation of a bFGF or VEGF-containing matrigcl plug (0.5 mL/20g mouse) for 6 days, a significant angiogenic effect was detected in the plug. Intraperitoneal injection of a piperazinedione compound almost completely diminished the angiogenic effect
OTHER EMBODIMENTS
All of the features disclosed in this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features.
From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. For example, compounds structurally analogous the piperazinedlone compounds of this invention also can be made, screened for their anti-tumor activities, and used to practice this invention. Thus, other embodiments are also within the claims.

WE CLAIM:
Piperazinedione compounds of the formula:
(Formula Removed)
wherein
A is C(RaRb);
Z is R30-(Ar)-B, in which B is C(RC); Ar is pyridyl linked to B at position 2; R3 is H, alkyl substituted with aryl or aryl; in which aryl is unsubstituted or substituted with one or more substitutents selected from the group consisting of halogen, hydroxyl, amino, alkylamino, arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbamido, carbamoyl, carboxyl, thioureido, thiocyanato, sulfonamide, C~C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy, and aryl;
each of Ri and R2, independently, is H, or C(O)Rd; and
one of Ra and Rb is thienyl, furyl, pyridinyl, indolyl, 2-oxo-indolyl, aryl, alkyl or alkyl substituted with aryl and each of the other of Ra and Rb, and Rc and Rd, independently is H, alkyl or aryl; in which alkyl and aryl are unsubstituted or substituted with one or more substitutents selected from the group consisting of halogen, hydroxyl, amino, alkylamino, arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbamido, carbamoyl, carboxyl, thioureido, thiocyanato, sulfonamide, C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy and aryl.
2. The compound as claimed in claim 1, wherein Rc is H.
3. The compound as claimed in claim 2, wherein R3O is linked to position 5 of pyridyl.
4. The compound as claimed in claim 3, wherein R3O is arylalkoxy.
5. The compound as claimed in claim 4, wherein both Ri and R2 are H.
6. The compound as claimed in claim 5, wherein one of Ra and Rb is aryl or thienyl, furyl, pyridinyl, indolyl or 2-oxo-indolyl and the other of Ra and Rb is H.
7. The compound as claimed in claim 6, wherein R3O is benzyloxy.
8. The compound as claimed in claim 1, wherein R3O is arylalkoxy.
9. The compound as claimed in claim 1, wherein both Ri and R2 are H.
10. The compound as claimed in claim 9, wherein Rc is H.
11. The compound as claimed in claim 1, wherein one of Ra and Rb is aryl or thienyl, furyl, pyridinyl, indolyl or 2-oxo-indolyl and the other of Ra and Rb is H.
12. The compound as claimed in claim 11, wherein Rc is H.
13. The compound as claimed in claim 12, wherein R3O is arylalkoxy linked to position 5 of pyridyl.
14. The compound as claimed in claim 1, wherein the compound is
(Formula Removed)
wherein Bn is benzyl.
15. The compound as claimed in claim 14, wherein the compound is
(Formula Removed)
16. The compound as claimed in claim 14, wherein the compound is
(Formula Removed)

Documents:

in-pct-2002-01192-del-abstract.pdf

in-pct-2002-01192-del-claims.pdf

in-pct-2002-01192-del-complete specification (granted).pdf

in-pct-2002-01192-del-correspondence-others.pdf

in-pct-2002-01192-del-correspondence-po.pdf

in-pct-2002-01192-del-description (complete).pdf

in-pct-2002-01192-del-form-1.pdf

in-pct-2002-01192-del-form-18.pdf

in-pct-2002-01192-del-form-2.pdf

in-pct-2002-01192-del-form-3.pdf

in-pct-2002-01192-del-form-5.pdf

in-pct-2002-01192-del-gpa.pdf

in-pct-2002-01192-del-pct-101.pdf

in-pct-2002-01192-del-pct-210.pdf

in-pct-2002-01192-del-pct-220.pdf

in-pct-2002-01192-del-pct-331.pdf

in-pct-2002-01192-del-pct-401.pdf

in-pct-2002-01192-del-pct-408.pdf

in-pct-2002-01192-del-pct-409.pdf

in-pct-2002-01192-del-pct-416.pdf

in-pct-2002-01192-del-petition-137.pdf

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Patent Number

233152

Indian Patent Application Number

IN/PCT/2002/01192/DEL

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

27-Mar-2009

Date of Filing

04-Dec-2002

Name of Patentee

CHI-MING TENG

Applicant Address

100 SGY-WEI ROAD, TAIPAI 106, TAIWAN

Inventors:

#	Inventor's Name	Inventor's Address
1	CHI-MING TENG	100 SGY-WEI ROAD, TAIPAI 106, TAIWAN
2	HUI -PO WANG	3RD FLOOR, 13 LANE, 199, SHIN-YI ROAD, SEE 4, TAIPAI, TAIWAN
3	ON LEE	8, LANE 127, GIA-HSING STREET, TAIPAI 110, TAIWAN
4	HUEI-TING CHEN	4TH FLOOR, 27 LANE 143, REN-AI ROAD, SEC. 3, TAIPAI, TAIWAN
5	YAN-BING FAN	35, FWU-TAY STREET, TAY-SHAN 243, TAIWAN
6	YA-LAN CHEN	26-1, LANE 112, WEI-KUO STREET, EAST AREA, TAIWAN CITY, TAIWAN
7	ERIC I. C. LI	NO. 74-J, LANE 93, TUNG-LIN ROAD, TAINAN CITY, TAIWAN
8	JIH HWA GUH	B1 FLOOR NO. 60, LANE 394, WU-SHIN STREET, TAIPAI 110, TAIWAN

PCT International Classification Number

A61K 31/496

PCT International Application Number

PCT/US01/14721

PCT International Filing date

2001-05-08

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	09/567,271	2000-05-09	U.S.A.