The standard method for preparing carboxylicacid hydrazides is hydrazinolysis of esters in alcoholicsolutions. However, when applied to
,
-unsaturated esters,the main product typically is the pyrazolidinone resultingfrom an undesired Michael-type cyclization. Other alternative methodologies reported for direct preparation of hydrazides from acids are inefficient. We developed an efficientand general process, involving preforming activated estersand/or amides followed by reaction with hydrazine, for thepreparation of hydrazides including those of
,
-unsaturatedacids. This process gives the desired hydrazides in excellentyield and purity under mild conditions.