Synthesis of thiophene and N-substituted thieno[3,2-d] pyrimidine derivatives as potent antitumor and antibacterial agents.

A novel series of carbamothioylamino-benzene-sulfonamide-thiophene-carboxylates 4a-c and thieno[3,2-d]pyrimidin-2-yl-amino-benzene-sulfonamides 5a-c were synthesized in a series of synthetic steps and were used as key intermediates for the synthesis of thienotriazolopyrimidine-benzene-sulfonamide derivatives 6a-c and 7a-c. Thieno[3,2-d]pyrimidinones (8 and 9) were also prepared. Compound 9 was used as an intermediate for the synthesis of imidazole/1,2,4-triazole and tetrazine functionalized thieno[3,2-d]pyrimidine derivatives (10-12). Pyrrole derivatives/pyrrolopyrimidine/pyrrolotriazolopyrimidine functionalized thiophenes (15-19) were also synthesized. Structures of the newly synthesized compounds were established by elemental analysis and spectral data. Most of the newly synthesized compounds were evaluated for their in vitro activity against three human tumor cell lines, namely, liver cancer (HepG-2), colon cancer (HT-29) and lung cancer (NCI-H460), using doxorubicin as standard. Compounds 16 (GI50 = 0.02, 0.04 and 0.06 µmol L-1, resp.) and 19b (GI50 = 0.02, 0.03 and 0.05 µmol L-1, resp.) showed higher activity against all cell lines than doxorubicin. Most of the compounds were also screened for antibacterial activity using ciprofloxacin as standard drug. Compounds 4b and 6b, both containing benzenesulfonamide linked to N-, 10 bearing imidazole moiety, and 15 and 19b,c with a thiophene-2-carboxylic acid chain, exhibited high activity against Gram-positive and Gram-negative bacteria.

Synthesis and evaluation of antitumor activity of new 4-substituted thieno[3,2-d]pyrimidine and thienotriazolopyrimidine derivatives.

3-Methyl-6-phenyl-2-thioxo-2,3-dihydrothieno[3,2-d]pyrimidin- 4(1H)-one (2), on treatment with phosphorous oxychoride, affored 4-chloro-3-methyl-6-phenyl -thieno[3,2-d]pyrimidine- 2(3H)-thione (3). A series of novel 6-phenyl-thieno[3,2-d]pyrimidine derivatives 4-9 bearing different functional groups were synthesized via treatment of compound 3 with different reagents. On the other hand, compound 2 was used to synthesize ethyl-[(3-methyl-6-phenyl-2-thioxo-2,3-dihydrothieno[ 3,2-d]pyrimidin-4-yl)-oxy]acetate (10), 2-hydrazinyl- -3-methyl-6-phenyl-thieno[3,2-d]pyrimidin-4(3H)-one (11), 3-methyl-2-(methyl-sulfanyl)-6-phenyl-thieno[3,2-d]pyrimidin- 4(3H)-one (12) and N-(phenyl)/4-chlorophenyl or methoxy- phenyl)-2-[(3-methyl-4-oxo-6-phenyl-3,4-dihydrothieno[ 3,2-d]pyrimidin-2-yl)-sulfanyl]-acetamide (13a-c). In addition, compound 12 was used to synthesize thieno[1,2,4] triazolopyrimidine derivatives 14 and 15 and 3-methyl-2-(methyl-sulfonyl)-6-phenyl-thieno[3,2-d]pyrimidin-4(3H)-one (16) through the reaction with the respective reagents. Moreover, the reaction of 16 with 4-phenylenediamine gave 2-[(4-aminophenyl)-amino]-3-methyl-6-phenyl-thieno[3,2-d] pyrimidin-4(3H)-one (17), which reacted with methanesulfonyl chloride to afford N-{4-[(3-methyl-4-oxo-6-phenyl-3H,4H- -thieno[3,2-d]pyrimidin-2-yl)-amino]phenyl}-methanesulfonamide (18). The majority of the newly synthesized compounds displayed potent anticancer activity, comparable to that of doxorubicin, on three human cancer cell lines, including the human breast adenocarcinoma cell line (MCF-7), cervical carcinoma cell line (HeLa) and colonic carcinoma cell line (HCT- 116). Compounds 18, 13b and 10 were nearly as active as doxorubicin whereas compounds 6, 7b and 15 exhibited marked growth inhibition, but still lower than doxorubicin.

A Simple Precursor for Highly Functionalized Fused Imidazo[4,5-b]pyridines and Imidazo[4,5-b]-1,8-naphthyridine.

1-alkyl aryl-5-amino-4-(cyanoformimidoyl)imidazoles 4 were reacted with malononitrile and 2-amino-1,1,3-propenetricarbonitrile under mild experimental conditions, which led to 5-amino-3-(substituted benzyl)-6,7-dicyano-3H-imidazo[4,5-b]pyridines 5 and 6,8-diamino-3-(4-substituted benzyl)-3H-imidazo[4,5-b]-1,8-naphthyridine-7,9-dicarbonitrile 6, respectively, when the reaction was carried out in the absence of a base, or to 5,7-diamino-3-(4-alkyl aryl)-3H-imidazo[4,5-b]pyridine-6-carbonitrile 8, and 6,8,9-triamino-3-(4-substitutedbenzyl)-3H-imidazo[4,5-b]-1,8-naphthyridine-7-carbonitrile 10 in the presence of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU). Both reactions evolved from an adduct formed by nucleophilic attack of the malononitrile anion or 2-amino-1,1,3-propenetricarbonitrile anion to the carbon of the cyanoformimidoyl substituent. In the case of the malononitrile anion, a 5-amino-1-alkyl aryl-4-(1-amino-2,2-dicyanovinyl)imidazole 7 was isolated when this reaction was carried out in the presence of DBU. The structure of compound 7 was confirmed by spectroscopic methods, and cyclized intramolecularly to 8 by heating in ethanol/triethyl amine.

Synthesis and Biological Evaluation of N- Pyrazolyl Derivatives and Pyrazolopyrimidine Bearing a Biologically Active Sulfonamide Moiety as Potential Antimicrobial Agent.

A series of novel pyrazole-5-carboxylate containing N-triazole derivatives 3,4; different heterocyclic amines 7a-b and 10a-b; pyrazolo[4,3-d]pyrimidine containing sulfa drugs 14a,b; and oxypyrazolo[4,3-d]pyrimidine derivatives 17, 19, 21 has been synthesized. The structure of the newly synthesized compounds was elucidated on the basis of analytical and spectral analyses. All compounds have been screened for their in vitro antimicrobial activity against three gram-positive and gram-negative bacteria as well as three fungi. The results revealed that compounds 14b and 17 had more potent antibacterial activity against all bacterial strains than reference drug Cefotaxime. Moreover compounds 4, 7b, and 12b showed excellent antifungal activities against Aspergillus niger and Candida albicans in low inhibitory concentrations but slightly less than the reference drug miconazole against Aspergillus flavus.

Simple approach to thieno[3,2-d]pyrimidines as new scaffolds of antimicrobial activities.

6'-(4-Chlorophenyl)-spiro[cyclohexane-1,2'-thieno[3,2-d][1,3] oxazin]-4'(1'H)-one (1) was synthesized and used as a starting material for the synthesis of a novel series of spiro compounds having biologically active sulfonamide 2a-e and 3'-(4-acetylphenyl)-6'- (4-chlorophenyl)-1'H-spiro[cyclohexane-1,2'-thieno[3,2-d] pyrimidine-4'(3'H)-one (3). Compound 2a was used as a key intermediate for the synthesis of sulfonyl carbothioamide derivatives 4a-c. Also, compound 3 was used as an intermediate for the synthesis of 3'H-spiro[cyclohexane-1,2'-thieno[3,2-d]pyrimidin]-3'-yl] phenyl}-2-imino-4-(substituted phenyl and/or thienyl)-1,2-dihydropyridine- 3-carbonitrile derivatives 5a-e, 3'H-spiro[cyclohexane- 1,2'- thieno[3,2-d]pyrimidin]-3'-yl]phenyl}-2-oxo-4-(substituted phenyl and/or thienyl)-1,2-dihydropyridine-3-carbonitrile derivatives 6a-e, and 4-[(2Z)-3-substituted-arylprop-2-enoyl] phenyl-1'H-spiro[cyclohexane-1,2'-thieno[3,2-d]pyrimidine derivatives 7a-e. Cyclocondensation of 7a-e with hydrazine hydrate produced 6'-(4-chlorophenyl)-3'-[4-(5-substituted aryl-4,5-dihydro- 1H-pyrazol-3-yl)phenyl]-1'H-spiro[cyclohexane-1,2'-thieno- [3,2-d]pyrimidin]-4'(3'H)-ones 8a-e but with hydroxylamine hydrochloride afforded the corresponding isoxazoline derivatives 9a-e. Also, cyclocondensation by thiourea afforded 2-thioxo-1,2- dihydropyrimidin-4-yl)-phenyl-spiro-{cyclohexanethieno[3,2-d] pyrimidin}-4-one derivatives 10a-e. The new compounds were investigated for antimicrobial activity. Compounds 2c, 8b,c, 9b and 10b were the most potent ones against both Gram-negative and Gram-positive bacteria. Compound 8c exhibited higher antifungal activity towards the examined fungi with MIC of 1-2 µmol mL-1 compared to ketoconazole (MIC 2-3 µmol mL-1 ).

Novel pyrazole derivatives with oxa/thiadiazolyl, pyrazolyl moieties and pyrazolo[4,3-d]-pyrimidine derivatives as potential antimicrobial and anticancer agents.

A series of [4-amino-3-(4-chlorophenyl)-1H-pyrazol-5-yl](3,5-dimethyl-1H-pyrazol-1-yl)-methanone and 6-amino-3-(4-chlorophenyl)-5-methyl-1,6-dihydro-7H-pyrazolo[4,3-d]-pyrimidin-7-one have been synthesized from ethyl 4-amino-3-(4-chlorophenyl)-pyrazol-5-carboxylate. The newly synthesized compounds were characterized by IR, (1)H NMR, (13)CNMR, Mass spectra and Elemental analysis. The compounds were evaluated for their in vitro antimicrobial and anticancer activity. Among the synthesized compounds, compounds 7a,b and 15 exhibited higher anticancer activity than the doxorubicin as reference drug. Most of the newly synthesized compounds have good to excellent antimicrobial activity.

Facile heterocyclic synthesis and antimicrobial activity of polysubstituted and condensed pyrazolopyranopyrimidine and pyrazolopyranotriazine derivatives.

Reaction of 6-amino-3-methyl-4-(substituted phenyl)-1,4- dihydropyrano[2,3-c]pyrazole-5-carbonitrile (1) with triethylorthoformate followed by treatment with hydrazine hydrate, formic acid, acetic acid, phenylisocyanate, ammonium thiocyanate and formamide afforded the corresponding pyranopyrimidine derivatives 2-6. Cyclocondensation of 1 with cyclohexanone afforded pyrazolopyranoquinoline 7. One-pot process of diazotation and de-diazochlorination of 1 afforded pyrazolopyranotriazine derivative 8, which upon treatment with secondary amines afforded 9 and 10a- c. Condensation of 2 with aromatic aldehyde gave the corresponding Schiff bases 11a,b, the oxidative cyclization of the hydrazone with appropriate oxidant afforded 11-(4- fluorophenyl))- 2-(4-substituted phenyl)-10-methyl-8,11-dihydropyrazolo-[ 4',3':5,6]pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines (12a,b). Structures of the synthesized compounds were confirmed by spectral data and elemental analysis. All synthesized compounds were evaluated for antibacterial and antifungal activities compared to norfloxacin and fluconazole as standard drugs. Compounds 9, 10c, 12a and 15 were found to be the most potent antibacterial agents, with activity equal to that of norfloxacin. On the other hand, compound 5 exhibited higher antifungal activity compared to fluconazole.

Synthesis of pyranopyrazolo N-glycoside and pyrazolopyranopyrimidine C-glycoside derivatives as promising antitumor and antimicrobial agents.

As a part of systematic investigation of the synthesis and biological activities of pyrazole analogues linked to various heterocyclic systems, a new series of pyrazolo-N-glycoside derivatives, pyrazolopyranopyrimidine and C-glycoside of pyrazolopyranotriazolo-pyrimidine derivatives was synthesized through the reaction of the key intermediate 6-amino-3-methyl-4-(substituted-phenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (3a,b) with different reagents. Structures of the newly synthesized compounds were elucidated by elemental microanalysis and spectroscopic methods. The compounds were subjected to in vitro antitumor evaluation using the MTT assay. N-(ß-D-ribofuranosyl)- and N-(ß-D-xylofuranosyl)-6{[(1E)-4-chlorophenyl)-methylene] amino}4-(4-florophenyl)-3-methyl-1,4-dihydropyrano[2,3-c]-pyrazole-5-carbonitrile (6a,b) were the most active compounds against three human cancer cell lines. Also, most of the newly synthesized compounds exhibited high activity towards Gram-negative and Gram-positive bacteria. Compound 6a exhibited excellent activity towards bacteria compared to ofloxacine as the reference drug.