Etify A. Bakhite

Recent Trends in the Chemistry of Thienopyridines

The nomenclature, synthesis, and reactions of various isomeric thienopyridines as well as their applications are reviewed.

SYNTHESIS OF SOME NEW THIENO[2,3-b]PYRIDINES, PYRIDO[3′,2′:4,5]-THIENO[3,2-d]PYRIMIDINES AND PYRIDO[3′,2′:4,5]THIENO[3,2-d][1,2,3]-TRIAZINES

Abstract 4-Aryl-3-cyano-2-substituted-methyIthiocyclopenta[b]pyridines (3a-c and 4a-i) were prepared by reaction of 4-aryl-3-cyanocyclopenta[b]pyridine-2(1H)-thiones(2a-c) with chloroacetonitrile or chloro-N-arylacetamides, respectively. On treatment of these products with sodium ethoxide in boiling ethanol, they underwent intramolecular Thorpe-Ziegler cyclization to afford the corresponding 3-amino-4-aryl-2-functionallized-cyclopenta[e]thieno [2,3-b]pyridines (5a-c and 6a-i). Most of the latter thienopyridines were used as synthons for the target cyclopenta[5′,6′]pyrido[3′,2′:4.5]thieno[3,2-d]pyrimidines and cyclopenta[5′,6′]. pyrido[3′,2′:4,5]thieno[3,2-d][1,2,3]triazines.

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME NEW PYRIDO[3′,2′:4,5]THIENO[3,2-d]- PYRIMIDINE DERIVATIVES

5-Acetyl-3-amino-4-aryl-6-methylthieno[2,3-b]pyridine-2-carboxamides (1a, b) were reacted with aromatic aldehydes or with some cycloalkanones to give the corresponding tetrahydropyridothienopyrimidinone derivatives 2a–f and 4a–d . The reaction of compound 1b with urea and/or carbon disulfide has been carried out and their products were identified. Some representative compounds were screened in vitro for their antimicrobial activities.

SYNTHESIS AND SOME REACTIONS OF PYRROLO[1″,2″:1′,6′]PYRAZINO-[2′, 3′: 4, 5]THIENO[2, 3-b]QUINOLINES; A NEW FUSED PYRAZINE RING SYSTEMS

Abstract Ethyl 3-amino-4-(4-chlorophenyl)-5, 6, 7, 8-tetrahydrothieno[2, 3-b]quinoline-2-carboxylate (1) was converted into the corresponding 3-(1-pyrrolyl) derivative 2. Various derivatives of 2 were prepared. The synthesis of the title compounds and other related heterocyclic systems are reported.

SYNTHESIS AND BIOLOGICAL ACTIVITY OF SOME NEW HETEROCYCLIC QUINOLINE DERIVATIVES

Abstract Alkylation of 2-mercapto-3-cyano-4-aryl-5,6,7,8-tetrahydroquinoline (I) gave compounds II–IV. Cyclization of III and IV afforded thienoquinolines V and VI respectively. On diazotization of V and VI, the corresponding triazinone derivatives VII and VIII were obtained. Also, reaction of V with benzoyl chloride yielded the tetracyclic compound IX. Structures of the new compounds were established by their elemental analyses and spectral data. Some of these compounds were screened in vitro for their antibacterial activities.

SYNTHESIS AND REACTIONS OF SOME NEW HETEROCYCLIC COMPOUNDS CONTAINING THE THIENYLTHIENO[2,3-B]PYRIDINE MOIETY

(4-Aryl-3-cyano-6-(2-thienyl)pyridin-2-ylthio)acethydrazides (5a–c), 3-amino-4-aryl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carbohydrazides (6a–c) and 3-amino-4-phenyl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carboxylic acid (30) were prepared and employed as key intermediates in the synthesis of the title compounds.

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME NEW PYRAZOLES AND THIEN0[2,3-c]PYRAZOLES

Abstract Starting with 5-chloro-1,3-diphenyl- 1H-pyrazole-4-carboxaldehyde (1), both of (4-cyano-1,3-diphenyl-1H-pyrazol-5-ylthio) acethydrazide (6) and 1,3-diphenyl- 1H-thieno[2,3-c] pyrazole-5-carbohydrazide (15) were synthesized. These hydrazides (6 and 15) were used as key intermediates in the synthesis of other new pyrazoles 7–12 and thieno[2,3-c]pyrazoles 16–30 respectively. Some of the prepared compounds were screened in vitro for their antibacterial and antifungal activity.

SYNTHESIS AND ANTIBACTERIAL ACTIVITIES OF SOME NEW THIENO-[2,3-b]QUINOLINES

Abstract 3-Cyanoquinoline-2(1H)-thione (1) was reacted with some halocompounds to give S-substituted thioquinoline derivatives 2, 6 and 7. Cyclization of 7 yielded thienoquinoline 8. Also, reaction of 1 with chloroacetone, chloroacetonitrile, ethyl chloroacetate and chloroacetamide furnished thienoquinolines 3, 4, 5 and 8, respectively. Moreover, compounds 4 and 8 underwent different sequence reactions to give some new pyrimido- and triazino-[4′,5′:4,5]thieno[2,3-b]quinoline derivatives (9–21). Most of the prepared compounds were screened in vitro for their antibacterial activities.

SYNTHESIS OF SOME NEW HETEROCYCLIC COMPOUNDS CONTAINING THIENO[2,3-b]QUINOLINE MOIETY

Abstract 2-Cyano-3-amino-4-aryl-5, 6, 7, 8-tetrahydro-thieno[2,3-b]quinoline (1) reacted with carbon disulfide to give compound 2. Alkylation of 2 with different reagents gave the corresponding thioethers 3–7. Diazotisation of 1 furnished chloro derivative 8 which reacted with thiourea to give mercaptotriazine 9. Methylation of 9 yielded 10. On treatment of 8 with hydrazone hydrate, the expected hydrazinocompound 11 was obtained. Reaction of 11 with aromatic aldehydes, acetylacetone, acetic acid, acetic anhydride, carbon disulfide and nitrous acid gave compounds 12–17, respectively. The structures of all synthesized compounds were confirmed by elemental and spectral analysis.

Convenient heterocyclization reactions with 2-functionalized 3-amino-4-aryl-5,6,7,8-tetrahydrothieno[2,3- b ]quinolines: synthesis of new thienoquinolines, pyridothienoquinolines, pyranothienoquinolines and pyrimidothienoquinolines

2-Functionalized-3-amino-4-aryl-5,6,7,8-tetrahydrothieno[2,3-b]quinolines (3a-e) underwent a sequence of heterocyclization reactions to afford the title compounds.