Abdu E. Abdel-rahman

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 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 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.

Fluorine-containing heterocycles: Part I. Synthesis of new 7-(2-thienyl)-9-trifluoromethylpyrido[3‘,2‘:4,5]thieno[3,2-d]pyrimidines and related fused tetracyclic systems

3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carboxamide (3) and 2-carbonitrile analogue 5 were prepared by reaction of 3-cyano-6-(2-thienyl)-4-trifluoromethylpyridine-2(1H)-thione (1) with chloroacetamide or chloroacetonitrile respectively. Heating compound 3 with triethyl orthoformate led to the formation of pyridothienopyrimidinone derivative 6. Reaction of 6 with phosphorus oxychloride produced 4-chloropyrimidine derivative 7 which underwent some nucleophilic displacements upon treatment with thiourea, piperidine, morpholine or hydrazine hydrate to give the target 4-substituted pyridothienopyrimidines 8, 10a, 10b and 11 respectively. Reaction of compound 8 with methyl iodide or ethyl chloroacetate gave compounds 9a,b. The condensation of 3-amino-6-(2-thienyl)-4-trifluoromethyl-thieno[2,3-b]pyridine-2-carbonitrile (5) with triethyl orthoformate led to the formation of methanimidate derivative 21 which upon treatment with hydrazine hydrate gave the target 3-amino-3,4-dihydro-4-imino-7-(2-thienyl)-9-trifluoromethylpyrido[3′,2′:4,5] thieno[3,2-d]pyrimidine (22). The reactions of compounds 11 and 22 with some reagents namely; triethyl orthoformate, acetic anhydride, formic acid, acetic acid, acetylacetone benzaldehyde and/or diethyl malonate were carried out and their products were identified, in most cases as [1,2,4]triazolopyridothienopyrimidines via Dimroth rearrangement.

SYNTHESIS OF THIENOQUINOLINES: PART I. SYNTHESIS OF NOVEL HETEROCYCLO-THIENO[2,3-b]QUINOLINE DERIVATIVES

Abstract Ethyl 3-amino-4-(p-chlorophenyl)-5,6,7,8-tetrahydrothieno[2,3-b]quinoline-2-carboxylate (IIa ) was hydrolysed to the sodium salt of the corresponding acid (III) which upon treatment with acetic anhydride furnished the oxazinone derivative IV. Recyclization of IV with ammonium acetate, hydrazine hydrate and/or aniline afforded the pyrimidine derivatives V, VIII and X respectively. Alkylation of V gave the N-alkylated products VI and VII. Compound VIII condensed with p-nitrobenzaldehyde to give the Schiff base IX. On the other hand, condensation of 3-amino-4-(p-chlorophenyl)-5,6,7,8-tetrahydrothieno-[2,3-b]quinoline-2-carbonitrile (IIb ) with triethyl ortho-formate gave methanimidate derivative XI which reacted with hydrazine hydrate to yield XII. Treatment of XII with formic acid gave s-triazolo compound XIII.3-Amino-4-(p-chlorophenyl)-5,6,7,8-tetrahydro-thieno[2,3-b]quinoline-2-carboxamide (IIc ) was also reacted with phenyl isothiocyanate, phenyl isocyanate, carbon disulfide and/or nitrous acid ...

Synthesis of some new pyridothienopyrimidines and related [1,2,4]triazolopyridothienopyrimidines

4-Chloro-9-phenyl-7-(2-thienyl)pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine (5) and 3-amino-3,4-dihydro-4-imino-9-phenyl-7-(2-thienyl)pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine (19) were prepared and employed as precursors for synthesizing the fused-ring compounds of the title.

SYNTHESIS OF SOME NEW 3-ARYLOXYMETHYL- 4-PHENYL-5-(N-SUBSTITUTED CARBOXAMIDOMETHYLTHI0)-S-TRIAZOLES

Abstract 3-Aryloxymethyl-4-phenyl-5-mercapto-s-triazoles (Ia-c) have been synthesized and reacted with N-chloroacetyl derivatives of aromatic and/or heterocyclic amines to yield 5-(N-aryl/heterocyclyl)-carboxamidomethyl thio-s-triazole derivatives 2a-o and 3a-o respectively. Reaction of Ia-u with ethyl chloroacetate gave the corresponding esters 4a-c which were reacted with hydrazine hydrate to give hydrazides 5a-c. Condensation of 5a-c with aromatic aldehydes gave Schiff s bases 6a-u with on cycloaddition reaction with thioglycolic acid yielded 4-thiazolidinones 7a-g. Some of these compounds were screened in vitro for their antibacterial activities.