Reactivity of 2-Cyano-N-(4-(1-Methyl-1H-benzo[d]imidazol-2-yl)-3-(Methylthio)-1-Phenyl-1H-Pyrazol-5-yl)Acetamide: A Facile Synthesis of Pyrazole, Thiazole, 1,3,4-Thiadiazole and Polysubstituted Thiophene Derivatives

摘要

Treatment of 2-cyano-N-(4-(1-methyl-1H-benzo[d]imidazol-2-yl)-3-(methylthio)-1-phenyl-1H-pyrazol-5-yl) acetamide (4) with phenyl isothiocyanate gave the thiole derivative (6) which on treatment with hydrazonyl chlorides (7a-c) furnished 1,3,4-thiadiazole derivatives (9a-c). Reaction of cyanoacetamide derivative (4) with active methylene reagents such as malononitrile or ethyl cyanoacetate and elemental sulfur afforded the corresponding polysubstituted thiophene derivatives (18a,b). Reaction of cyanoacetamide derivative (4) with benzaldehyde yielded the phenylmethylidene derivative (21). The latter showed interesting reactivity towards cyanomethylene reagent and hydrazine derivatives afforded pyrane (22a,b) and pyrazole (25a,b) derivatives.