Abstract
Author(s): Rekha Parmesh, Lohitha P, Saravanan J
In this present work, a series of new 2-[(substituted benzylidene) imino]-3-(N-cyclohexl carboxamido)-4,5-di substituted thiophenes were synthesized in a multi step method and its structure has been elucidated by elemental analysis and spectral tools.. In the first step N-cyclohexyl cyano acetamide MSR-5 was synthesized by the condensation of Cyclohexylamine and Ethyl cyano acetate. Reaction of compound MSR-5 with methylenic ketone using ammonium acetate and glacial acetic acid as an acidic catalyst was carried out by refluxation in benzene for 8hrs by employing Dean Stark apparatus afforded 2-Cyano –2- (alkylidene)-N-cyclohexyl carboxamides [I]. Compound [I] represents the important key intermediate from which all the new target polysubstituted thiophenes were synthesized thus compound [2] was introduced in reaction by dissolving in alcohol react with elemental sulfur in the presence of basic catalyst, diethyl amine in ethanol to form 2-amino-3-(cyclohexyl carboxamido)-4,5-di substituted thiophenes MSR-11 & 12. In the final step a new series of compounds were synthesized from 2-amino-3-N-cyclohexyl carboxamido-4,5-disubstituted thiophenes (MSR-11&12) by heating in a microwave oven with various substituted aromatic aldehydes in isopropyl alcohol with glacial acetic acid as a catalyst to yield 2-[(substituted benzylidene) imino]-3-(N-cyclohexl carboxamido)-4,5-disustituted thiophenes MSR-11a-11k & MSR-12a-12k.