Chemistry:Acylhydrazine

An example of an acylhydrazine. This compound has been called acetylhydrazide, acetohydrazide, or acetic acid hydrazide.

Acylhydrazines are a class of organic compounds and can be regarded as nitrogen derivatives of carboxylic acids having the general structure R-CO-NR¹-NR²R³, where R¹, R² and R³ can be organic radicals or hydrogen. They are analogous to an amide, but the -OH portion of a carboxylic acid is replaced by hydrazine rather than ammonia (one less hydrogen at the point of attachment). Acylhydrazines are a type of hydrazides.

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  Formylhydrazide, a derivative of formic acid

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  Acetylhydrazide, a derivative of acetic acid

Preparation

Carboxylic hydrazides can be prepared by reacting acyl halides with hydrazine (or correspondingly substituted hydrazines) or by reduction of N-nitroso carboxamides.

Properties

Carboxylic hydrazides are stable, polar solids and partially pharmacologically active.

Use

Acylhydrazines are intermediates in chemical syntheses, for example in the synthesis of nitrogen heterocycles and acyl azides.

An applied example is a synthesis of sunitinib begins by mixing 5-fluoroisatin slowly into hydrazine hydrate. After 4 hours at 110 °C, the indole ring structure has been broken into (2-amino-5-fluoro-phenyl)-acetic acid hydrazide with reduction of the ketone at the 3-position. Subsequent annelation in strong acid creates the 1,3-dihydro-2-oxo indole structure required for the drug.