A new procedure for preparation of carboxylic acid hydrazides.
The standard method for preparing carboxylic acid hydrazides is hydrazinolysis of esters in alcoholic solutions. However, when applied to alpha,beta-unsaturated esters, the main product typically is the pyrazolidinone resulting from an undesired Michael-type cyclization. Other alternative methodologies reported for direct preparation of hydrazides from acids are inefficient. We developed an efficient and general process, involving preforming activated esters and/or amides followed by reaction with hydrazine, for the preparation of hydrazides including those of alpha,beta-unsaturated acids. This process gives the desired hydrazides in excellent yield and purity under mild conditions.
Zhang
Xini
X
Johnson & Johnson Pharmaceutical Research & Development, L.L.C., Drug Evaluation, 1000 Route 202, Raritan, New Jersey 08869, USA. xzhang@prdus.jnj.com
Breslav
Michael
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Grimm
Jeffrey
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Guan
Kailin
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Huang
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Liu
Fuqiang
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Maryanoff
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Palmer
David
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Patel
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Qian
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Shaw
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Stefanick
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