Synthesis and antiallergy activity of 10-oxo-10H-pyrido[1,2-a]thieno[3,2-d]pyrimidines and 10-oxo-10H-pyrido[1,2-a]thieno[3,4-d]pyrimidines

Synthesis and antiallergy activity of 10-oxo-10H-pyrido[1,2-a]thieno[3,2-d]pyrimidines (2 and 3) and 10-oxo-10H-pyrido[1,2-a]thieno[3,4-d]pyrimidines (4 and 5) are described. The activity, shown by these compounds in the rat passive cutaneous anaphylaxis (PCA) test, is compared to the PCA data previously reported for a series of 4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidines. 10-Oxo-N-1H-tetrazol-5-yl-10H-pyrido[1,2-a]thieno[3,4-d]pyri midine (2b), 10-oxo-7-(1H-tetrazol-5-yl)-10H-pyrido[1,2-a]thieno[3,4-d]py rimidine (4e), and 3,10-dihydro-10-oxo-7-(1H-tetrazol-5-yl)-1H-pyrido[1,2-a]thieno[3, 4-d] pyrimidine (7e) gave a 100% inhibition in the rat PCA test at a dose of 5 mg/kg. The activity displayed by these compounds is comparable to that of the most active compounds in the 4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidine series.     

Synthesis and biological evaluation of some pyrimidine, pyrimido[2,1-b][1,3]thiazine and thiazolo[3,2-a]pyrimidine derivatives

4,6-Diamino-1H-pyrimidine-2-thione (1) was used for the preparation of pyrimidine derivatives 2-5. Compound 5 was cyclized to produce pyrimido[2,1-b][1,3]thiazine derivative 6 which was condensed with p-chlorobenzaldehyde to give compound 7. The latter compound was reacted with hydroxylamine to give isoxazolo[4,5-d]thiazino[2,3-a]pyrimidine 8. Compound 8b was treated with 2-chloroethyl methyl ether to afford compound 9. Similarly, compound 3 reacted with chloroacetic acid to give thiazolo[3,2-a]pyrimidine 10, which was condensed with p-chlorobenzaldehyde to give compound 11. Compound 11 was condensed with hydroxylamine to give isoxazolo[4,5-d]thiazolo[2,3-a]pyrimidine 12. Compound 12b was treated with 2-chloroethyl methyl ether to afford compound 13. Biological evaluation of some prepared products showed that many of them revealed promising antimicrobial activity.     

Synthesis of thieno[2,3-d]pyrimidine derivatives and their antifungal activities

4-Chlorothieno[2,3-d]pyrimidines were prepared by the chlorination of 4-oxo-3,4-dihydrothieno[2,3-d]pyrimidines with phosphoryl chloride. 4-Oxo-3,4,5,6,7,8-hexahydro[1]-benzo- and 4-oxo-6-phenylthieno[2,3-d]pyrimidine were synthesized by the cyclization of 2-acylaminothiophene-3-carboxamide derivatives with base. 2-Methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine was prepared by the treatment of 2-methyl-4-trichloromethylthieno-[2,3-d]pyrimidine with sodium hydroxide in aqueous methanol. A series of 4-alkylamino- and 4-arylaminothieno[2,3-d]pyrimidines were synthesized by the nucleophilic substitution of 4-chlorothieno[2,3-d]pyrimidines with various amines. These compounds were evaluated for antifungal activity against Piricularia oryzae. The preventive effects on Rice blast, Sheath blight, and Cucumber powdery mildew were also determined by pot tests.     

Synthesis and anticonvulsant activity of pyrano[4′,3′:4,5]pyrido[2,3-b]thieno[3,2-d] pyrimidine derivatives and pyrimido[5′,4′:2,3]-thieno[2,3-c]isoquinoline derivatives

Methods for the synthesis of condensed thieno[3,2-d]pyrimidines based on pyrano[4,3-d]thieno[2,3-b]pyridines and thieno[2,3-b]isoquinolines have been developed and a series of new derivatives have been synthesized. The anticonvulsant activity of the synthesized compounds has been studied. Several compounds possessing specific anticonvulsant activity with respect to corazole-induced convulsions are revealed. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 9, pp. 14–16, September, 2007.     

Synthesis and cytotoxicity of 4-amino-5-oxopyrido[2,3-d]pyrimidine nucleosides

A number of nucleoside analogues have been either used clinically as anticancer drugs or evaluated in clinical studies, while new nucleoside analogues continue to show promise. In this article, we report synthesis and cytotoxicity of a series of new pyrido[2, 3-d]pyrimidine nucleosides. 2-Amino-3-cyano-4-methoxypyridine was converted, in two steps, to 4-amino-5-oxopyrido[2,3-d]pyrimidine. A variety of 1-O-acetylated pentose sugar derivatives were condensed with silylated 4-amino-5-oxopyrido[2,3-d]pyrimidine, followed by protection, to afford a series of 4-amino-5-oxopyrido[2, 3-d]pyrimidine nucleosides. Further derivatizations provided an additional group of pyrido[2,3-d]pyrimidine nucleosides. These nucleosides were evaluated for in vitro cytotoxicity to human prostate cancer (HTB-81) and mouse melanoma (B16) cells as well as normal human fibroblasts (NHF). A number of compounds (1a,b, 2a-c,f, 3f+4d) showed significant cytotoxicity to cancer cells, with 4-amino-5-oxo-8-(beta-D-ribofuranosyl)pyrido[2,3-d]pyrimidine (1b) being the most potent proliferation inhibitor (EC(50): 0.06-0.08 microM) to all types of cells tested. However, a selective inhibition to the cancer cells was observed for 4-amino-5-oxo-8-(beta-D-xylofuranosyl)pyrido[2,3-d]pyrimidine (2b), which is a potent inhibitor of HTB-81 (EC(50): 0.73 microM) and has a favorable in vitro selectivity index (28).     

Synthesis of certain new thiieno [2,3-d] pyrimidines as potential antitumor and radioprotective agents

During research on anticancer and radioprotective heterocyclic compounds containing thiophene ring 5-10, 15, 19, thieno[2,3-d]pyrimidines 11-14 and biscompound having thieno[2,3-d]pyrimidine 18 were synthesized. The synthesized compounds were characterized by elemental ananlysis, IR, 1H-NMR and mass spectral data. Some of the obtained compounds showed interesting antitumor and radioprotective activities.     

Fluorine-containing heterocycles: synthesis and some reactions of new 3-amino-2-functionalized-6-(2'-thienyl)-4-trifluoromethylthieno [2,3-b]pyridines

3-Cyano-6-(2'-thienyl)-4-trifluoromethylpyridine-2(1H)-thione (2) was prepared and reacted with chloroacetone or phenacyl bromide to yield the 2-acetyl or benzoyl-3-amino-6-(2'-thienyl)-4-trifluoromethylthieno[2,3-b]pyridines (3a, b). In contrast, the reaction of 2 with chloroacetamide or its N-aryl derivatives gave the corresponding 2-carbamoylmethyl thiopyridines 4a-c. Upon treatment of these educts with K2CO3 or C2H5ONa in ethanol, they underwent intramolecular Thorpe-Ziegler cyclization to afford 3-amino-2-carbamoyl-6-(2'-thienyl)-4-trifluoromethyl-thieno[2,3-b]pyridine (5a) and its N-aryl analogs 5b, c. Compounds 5a-c underwent some reactions to yield new pyrido[3',2':4,5]thieno[3,2-d]pyrimidines and pyrido[3',2':4,5]thieno[3,2-d][1,2,3] triazines.     

Synthesis of classical, three-carbon-bridged 5-substituted furo[2,3-d]pyrimidine and 6-substituted pyrrolo[2,3-d]pyrimidine analogues as antifolates

Bridge homologation of the previously reported classical two-carbon-bridged antifolates, a 5-substituted 2,4-diaminofuro[2,3-d]pyrimidine (1) [which is a 6-regioisomer of LY231514 (Alimta)] and a 6-subsituted 2-amino-4-oxopyrrolo[2,3-d]pyrimidine, afforded the three-carbon-bridged antifolates analogues 4 and 5, with enhanced inhibitory activity against tumor cells in culture (EC(50) values in the 10(-8)-10(-7) M range or less). These two analogues were synthesized via a 10-step synthetic sequence starting from methyl 4-bromobenzoate (14), which was elaborated to the alpha-chloromethyl ketone (8) followed by condensation with 2,6-diamino-pyrimidin-4-one (7) to afford the substituted furo[2,3-d]pyrimidine 9 and the pyrrolo[2,3-d]pyrimidine 10. Subsequent coupling of each regioisomer with diethyl-l-glutamate followed by saponification afforded 4 and 5. The biological results indicate that elongation of the C8-C9 bridge of the classical 5-substituted 2,4-diaminofuro[2,3-d]pyrimidine and 6-substituted 2-amino-4-oxopyrrolo[2,3-d]pyrimidine are highly conducive to antitumor activity in vitro, despite a lack of increase in inhibitory activity against the target enzymes. This supports our original hypothesis that truncation of the B-ring of a highly potent 6-6 ring system to a 6-5 ring system can be compensated by bridge homologation to restore the overall length of the molecule.     

Study of the antidepressant activity of 4-phenyl-2-thioxo-benzo[4,5]thieno[2,3-d]pyrimidine derivatives

A series of 23 4-phenyl-2-thioxo-benzo[4,5]thieno[2,3-d]pyrimidine derivatives were tested for acute toxicity and antidepressant activity in mice. Eight of the 23 compounds tested clearly antagonised the tetrabenazine effects and four of them (5, 7, 19, 23) showed activity values ranging from 40 to 75%, close to those shown by imipramine and viloxazine, the drugs chosen as reference standards. Compounds 7, 19 and 23 were also notably effective in the Porsolt test, shortening the immobility period of mice by more than 20%. The values obtained were very close to those elicited by imipramine and viloxazine. The most effective compounds in these tests were found among those bearing a primary amine or a benzoylamino group at the position 3 of the thieno[2,3-d]pyrimidine general structure (7, 19 and 23). The substitution of the thioxocarbonyl group at position 2 by a methylmercapto substituent maintained the activity (23). Compounds 7, 19 and 23 were chosen as prototypes for the design of new molecules with better antidepressant activity. These compounds did not present the adverse anticholinergic effects found in most tricyclic antidepressant drugs.     

Synthesis and molluscicidal activity of some 1,3,4-triaryl-5-chloropyrazole, pyrano[2,3-c]pyrazole, pyrazolylphthalazine and pyrano[2,3-d]thiazole derivatives

2-(5-Chloro-1,3-diphenyl-1H-pyrazol-4-ylmethylene)-malononitrile 1a reacts with the arylidenes of malononitrile 2a-d to afford the triaryl-5-chloropyrazoles 3a-d, respectively. 1a reacts with the active methylene pyrazolinones 5a, b and 12a, b to afford different products 8, 9, 10, 11, and 14a, b--depending on the substitution in the pyrazole ring. Compound 1a reacts also with the pyridazinone derivative 15 to afford the phthalazinone 16, and with the thiazolinones 17a-c to afford the pyrano[2,3-d]thiazoles 20a-c, respectively. It reacts also with the malononitrile dimer 21a and with ethyl cyanoacetate dimer 21b to yield the pyrazolyl pyridines 22a, b, respectively. The synthesized compounds showed a moderate molluscicidal activity towards Biomphalaria alexandrina snails.     

Synthesis of new pyrido[4',3':4,5]thieno[2,3-d]-1,2,4-triazolo[3,4-c]pyrimidines and a 5,6-dihydro-1,2,4-triazolo[4",3":1',2']pyrido[4',3':4,5]thieno [2,3-d]-pyrimidine ring system

A series of substituted pyrido[4',3':4,5]thieno[2,3-d]-1,2,4-triazolo[3,4-c]pyrimidines 4-6, 8, pyrido[4',3':4,5]thieno[2,3-d]-1,2,4-triazolo[3,4-c]pyrimidines 11-13 and 5,6-dihydro-1,2,4-triazolo[4",3":1',2']pyrido[4',3':4,5]thieno[2,3-d] pyrimidines 16-19 have been synthesized from 3, 10 and 15 through the reaction with orthoesters and carbon disulphide, respectively.     

Synthesis and biological evaluation of thieno[2,3-d]pyrimidine derivatives for anti-inflammatory, analgesic and ulcerogenic activity

5-Methyl-6-phenyl-2-thioxothieno[2,3-d]pyrimidone derivative (2) reacted with hydrazonoyl chloride derivatives to afford triazolothienopyrimidones 4a-f. Also, acetone-1-(2-amino-5-isopropyl-thiophene-3-carbonitrile) (3) reacted with functional and bifunctional groups to yield the corresponding compounds 5-11. The new products showed anti-inflammatory, analgesic, and ulcerogenic activities comparable to that of indomethacin and acetylsalicylic acid, respectively.     

Novel pyrrolo[2,3-d]pyrimidine antifolates: synthesis and antitumor activities.

New antifolates, characterized by a 6-5 fused ring system, a pyrrolo[2,3-d]pyrimidine ring, and a trimethylene bridge at position 5 (12a,b and 13a,b) were designed and efficiently synthesized. The synthetic method included (1) construction of the key intermediary acyclic skeleton, 5-[4-(tert-butoxycarbonyl)phenyl]- 2-(dicyanomethyl)pentanoates (6a,b), (2) cyclization with guanidine, followed by reduction to the pyrrolo[2,3-d]pyrimidine derivatives (8a,b and 9a,b), and (3) subsequent glutamate coupling and saponification. These antifolates were more growth-inhibitory by about 1 order of magnitude than methotrexate (MTX) against KB human epidermoid carcinoma cells and A549 human nonsmall cell lung carcinoma cells in in vitro culture. Growth inhibitory IC50 values for N-[4-[3-(2,4-diamino-7H-pyrrolo[2,3-d]pyrimidin-5- yl)propyl]benzoyl]-L-glutamic acid (12a) against KB and A549 were 0.27 and 4.5 ng/mL, while those for MTX were 5.0 and 35 ng/mL, respectively. Other members of this class of antifolates, 12b and 13a,b, showed good activities nearly equal to that of 12a.     

Synthesis and pharmacological activity of 2-alkylthio substituted thieno[2,3-d]pyrimidine-4-one and 5H-pyrimido [5,4-b]indol-4-one

Quaternary salts of several 2-alkylthio substituted derivatives of thieno [2,3-d]pyrimidin-4-one and 5H-pyrimido [5,4-b]indol-4-one with a basic group in position 2 of the alkyl chain were synthesized and screened for potential spasmolytic activity. These substances were prepared by condensation of the corresponding mercapto compounds with a 2-chloroalkyltertiary amine. The tertiary bases were quaternized with methyl iodide. Among the assayed compounds, the thieno [2-3-d]pyrimidin-4-one derivatives displayed a potent spasmolytic activity in the in vitro and in vivo assays.     

Synthesis, cytotoxicity, and antiviral activity of some acyclic analogues of the pyrrolo[2,3-d]pyrimidine nucleoside antibiotics tubercidin, toyocamycin, and sangivamycin

A number of 7-[(1,3-dihydroxy-2-propoxy)methyl]pyrrolo[2,3d-d]pyrimidine derivatives that are structurally related to toyocamycin and sangivamycin and the seco nucleosides of tubercidin, toyocamycin, and sangivamycin were prepared and tested for their biological activity. Treatment of the sodium salt of 4-amino-6-bromo-5-cyanopyrrolo[2,3-d]-pyrimidine with 1,3-bis(benzyloxy)-2-propoxymethyl chloride afforded compound 3, which without isolation was debrominated to obtain 4-amino-5-cyano-7-[[1,3-bis(benzyloxy)-2- propoxy]methyl]pyrrolo[2,3-d]pyrimidine. Although catalytic hydrogenolysis failed, the benzyl ether functionalities of 4 were successfully cleaved by boron trichloride to afford 4-amino-5-cyano-7-[(1,3-dihydroxy-2- propoxy)methyl]pyrrolo[2,3-d]pyrimidine. Conventional functional group transformation of the cyano group of 6 provided a number of novel 5-substituted derivatives. Tubercidin (8a), toyocamycin (8b), and sangivamycin (8c) were treated separately with sodium metaperiodate and then with sodium borohydride to afford the 2',3'-seco derivatives 9a-c, respectively. The acyclic nucleoside 4-chloro-2-(methylthio)-7-[[1,3-bis(benzyloxy)-2- propoxy]methyl]pyrrolo[2,3-d]pyrimidine was aminated, desulfurized with Raney Ni, and then debenzylated to provide the tubercidin analogue 11. Cytotoxicity evaluation against L1210 murine leukemic cells in vitro showed that although the parent compounds tubercidin (8a), toyocamycin (8b), and sangivamycin (8c) were very potent growth inhibitors, the acyclic derivatives 6, 7a-c, and 9a-c had only slight growth-inhibitory activity. Evaluation of compounds 6, 7a, 7b, 7c, 9a, 9b, 9c, 11 for cytoxicity and activity against human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1) revealed that only the carboxamide (7a) and the thioamide (7c) were active. Compound 7c was the more potent of the two, inhibiting HCMV but not HSV-1 at concentrations producing little cytotoxicity.     

Synthesis, cytotoxicity, and antiviral activity of certain 7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine nucleosides related to toyocamycin and sangivamycin

A number of 7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine derivatives related to the nucleoside antibiotics toyocamycin and sangivamycin were prepared and tested for their biological activity. Treatment of the sodium salt of 4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidine (1) with (2-acetoxyethoxy)methyl bromide (2) afforded a mixture of 4-amino-6-bromo-5-cyano-7-[(2-acetoxyethoxy)methyl]pyrrolo[2,3-d] pyrimidine (3) and the corresponding N1 isomer. Debromination of this mixture gave the corresponding 4-amino-5-cyano-7-[(2-acetoxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidi ne (4) and 4-amino-5-cyano-1-[(2-acetoxyethoxy)methyl]pyrrolo[2,3-d]pyrimidin e (5). Deacetylation of 4 and 5 furnished 4-amino-5-cyano-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (6) and the corresponding N1 isomer (7), respectively. The sites of attachment for the acyclic moiety for 6 and 7 were assigned on the basis of UV spectral studies as well as 13C NMR spectroscopy. Conventional functional group transformation of 6 provided a number of novel 5-substituted derivatives (8-10), including the sangivamycin derivative 8. The methyl formimidate derivative 10 was converted to the thioamide derivative 11 and the carbohydrazide derivative 12. Compounds 6 and 8-12 were tested for cytotoxicity to L1210 murine leukemic cells in vitro. None of these compounds caused significant inhibition of cell growth. Evaluation of compounds 4 and 6-12 for activity against human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1) revealed that only the thioamide (11) was active. It inhibited HCMV but not HSV-1 at concentrations producing only slight cytotoxicity in human foreskin fibroblasts (HFF cells) and KB cells.     

Synthesis and receptor binding of new thieno[2,3-d]-pyrimidines as selective ligands of 5-HT(3) receptors

With the aim to develop new potent and selective ligands of 5-HT(3)-type serotonin receptors and to acquire more information on their structure-affinity relationships, new thieno[2,3-d]pyrimidine derivatives 32-39 were synthesized and their binding to 5-HT(3) versus 5-HT(4 )receptors was studied. Some of these new compounds exhibit good affinity for cortical 5-HT(3) receptors, but not for 5-HT(4) receptors. Among these derivatives, 6-ethyl-4-(4-methyl-1-piperazinyl)-2-(methylthio)thieno[2,3-d]pyrimidine 32 is the most potent ligand (K(i) = 67 nM); it behaves as a competitive antagonist of the 5-HT(3) receptor function in the guinea pig colon. Its binding interactions with 5-HT(3A )receptors were analysed by using receptor modelling and comparative docking.     

NSAI Activity Study of 4-Phenyl-2-thioxo-benzo[4,5]thieno [2,3-d]pyrimidine Derivatives

A series of 4-phenyl-2-thioxo-benzo[4,5]thieno[2,3-d]pyrimidine derivatives endowed with anti-inflammatory and related pharmacological properties were submitted to a more extensive study to know their exact pharmacological profile and their possible side effects. The studied compounds possess a remarkable analgesic activity, devoid of central effects. They also show an interesting anti-inflammatory profile evidenced by their effectiveness in different experimental models of inflammation. In addition, these compounds exhibit none or very little activity on CNS, scarce toxicity and low gastrointestinal agressivity.     

Synthesis and antiviral and cytostatic evaluations of the new C-5 substituted pyrimidine and furo[2,3-d]pyrimidine 4',5'-didehydro-L-ascorbic acid derivatives

The novel C-5 alkynyl substituted pyrimidine (1-11) and furo[2,3-d]pyrimidine derivatives (12-22) of l-ascorbic acid were synthesized by coupling of 5-iodouracil-4',5'-didehydro-5',6'-dideoxy-l-ascorbic acid with terminal alkynes by using Sonogashira cross-coupling reaction conditions. The new compounds were evaluated for their cytostatic and antiviral activities. Among all evaluated compounds, the octynyl-substituted uracil derivative of l-ascorbic acid (3) exhibited the most pronounced cytostatic activities against all examined tumor cell lines (IC50 = 2-12 microM). Pyrimidine derivatives of l-ascorbic acid containing p-substituted phenylacetylene groups (8-11) displayed also a rather pronounced (IC50 = 3-37 microM) inhibitory effect toward all tumor cell lines. From the bicyclic series of compounds, 6-butylfuro[2,3-d]pyrimidine derivative (12) and 6-p-bromophenylfuro[2,3-d]pyrimidine derivative (19) showed the highest cytostatic activity (IC50 = 4.5-20 microM), particularly against malignant leukemia (L1210) and T-lymphocyte (Molt4/C8 and CEM) cells. Compounds 3 and 9 showed specific albeit moderate activity against cytomegalovirus (CMV, Davis strain, EC50 = 1.8 and 3.8 microM, respectively, for compounds 3 and 9) at a approximately 5-fold lower concentration than that required to show cytotoxicity.     

Synthesis and anticancer activities of 4-oxobenzopyrano[2,3-d]pyrimidines

Several 2-aryl-4-oxoxbenzopyrano[2,3-d]pyrimidines have previously been shown to exhibit in vivo antitumor activity in mice with P388 lymphocytic leukemia. In the present study, a series of novel substituted benzopyrano[2,3-d]pyrimidines have been prepared and tested for cytotoxic activity against a panel of cancer cell lines including the P388 lymphocytic leukemia cell line. The unsubstituted parent compound, some methoxylated derivatives and a cyclohexyl derivative all exhibited potent cytotoxic activity (IC50 values 0.3-0.64 microM). A number of derivatives, including the unsubstituted parent pyrimidine, were shown to cause a significant perturbation in cell cycle kinetics with an observed 2- to 3-fold increase in cells in the G2/M phase of the cell cycle. Furthermore, a polymethoxylated derivative, 2-(3,4,5-trimethoxyphenyl)-9-methoxy-4-oxo-2,3-dihydrobenzopyrano[ 2,3-d]pyrimidine 13, was shown to be selectively active against a number of human ovarian cell lines.