2-thiophenecarbohydrazides: A novel efficient method for the synthesis of 2-thiophenecarbohydrazide

Abstract

Hydrazinolysis of carboxylic acid esters in alcoholic solutions is the standard method for preparing carbohydrazides (carboxylic hydrazides). Here we report an efficient process, involving the reaction of activated esters or amides with hydrazine, for the preparation of thiophenecarbohydrazides in yields larger than 90% and high purity. With this new method, a series of heteroaryl-, aryl-, or aralkyl- substituted carbohydrazides were synthesized and characterized. The X-ray crystal structure of 2-thiophenecarbohydrazide (thiophene-2-carboxylic hydrazide, 2-thenoyl-hydrazine) has revealed that it crystallizes in the monoclinic system, space group P21/c, with cell parameters of a = 6.1202(2), b = 8.3907(3), c = 12.5332(5) Å, β = 98.6577(11)?, Z = 4, R(F) = 0.0455 and wR(F2) = 0.1805, T = 293 K. © 2011 Verlag der Zeitschrift für Naturforschung, Tübingen.