Abstract
A simple and efficient process for the synthesis of novel heterocycles starting from thiocarbohydrazide was reported. Reaction of 2-acetylbenzofuran (1) and thiocarbohydrazide (2) in ethanol containing acetic acid produced the corresponding thiocarbohydrazone 3 in 86% yield. Reaction of 3 and isatin (4) gave N,2-bis(2-oxoindolin-3-ylidene)hydrazine-1-carbothiohydrazine (6) in 65% yield, rather than the expected product, 3-[(1-methyl-1-benzofur-2-ylmethylidene)amino]-1-{[(3Z)-2-oxo-2,3-dihydro-1H-indol-3-ylidene]amino}thiourea (5). Reaction of 2-((3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene)hydrazine carbothioamide (9) and chloroacetic acid or hydrazonoyl chloride 11 in basic medium gave (Z)-2-((E)-((3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene)hydrazono)thiazolidin-4-one (10) or 2-((E)-2-((3-(benzofuran-2-yl)-1- phenyl-1H-pyrazol-4-yl)methylene)hydrazinyl)-4-((E)-(4-fluorophenyl)diazenyl)-5-methylthiazole (12) in 62% or 74%, respectively.