Synthesis of Some Novel Pyridine, Thiophene, Thienopyrimidine and Thienopyridine Derivatives Containing Benzofuranyl Moiety

Abstract

Interaction of 2-[1-(4,6-dimethoxybenzofuran-5-yl)ethylidine]malononitrile (1) with phenylisocyanate, phenylhydrazine, carbon disulphide and arylidenemalononitrile afforded the corresponding pyridine 2, pyrido[2,3-d] pyrimidine 3, phenylhydrazone 4, pyridine 2,6-dithione 8 and benzene dicarbonitrile 9 derivatives . Treatment of 1 with elemental sulfur under Gewald reaction conditions furnished 2-amino-4-(4,6-dimethoxybenzofuran-5-yl)thiophen-3-carbonitrile 11 which used as starting material in the synthesis of thienopyrimidine 14 and thienopyridine 15 derivatives.

Synthesis of Some Novel Thiazole, Thiophene, Thienopyridine and Thienopyrimidine Derivatives Containing Tosyl Moiety

“…The reactivity of methyl function in compound 7 towards carbon disulfide and sulfur were investigated. Thus interaction of 7 with carbon disulfide yield thiazine derivative (8) which rearranged into pyridin-2,6-dithione derivative (9), which is in accordance with previous work (1,10) .…”

“…Reaction of 4-aminoacetophenone (1) with p-tolyl sulphonamide afforded 1-[4-tosyl amino) phenyl]ethanone (2). Structure of compound 2 was established by correct analytical data.…”

“…The IR spectrum of 4 showed the disappearance of carbonyl group found in parent compound and showed the absorption bands at 1620 (C=N), 3100 and 3194 & 3328 cm -1 [NH/NH2], 1 HNMR spectrum in (DMSO-d6) showed signals at  2.2 (s, 3H, CH3),  6.24 (s, 2H, NH2), 6.94 (s, 1H, thiazole), 7.1-7.52 (dd, 4H, Ar), 7.2-7.8 (m, 4H, Ar-H) and 9.0 (s, 1H, NH).…”

“…Infrared spectrum of 7 showed absorption bands at 3279 cm -1 (NH) and broad bands at 2198 for 2(CN) groups. 1…”

“…Activated nitriles have attracted considerable interest as potential building blocks for many nitrogen containing heterocyclic system (1)(2)(3) . Also, derivatives of thiazole, pyridine and pyrimidine show a variety of pharmacological effects (4)(5)(6) .…”