Hydrazides in organic chemistry are a class of organic compounds with the formula where R is acyl, sulfonyl, phosphoryl, phosphonyl and similar groups (chalcogen analogs are included, for example sulfur analogs called thiohydrazides),[1] and R' are any groups (typically hydrogen or organyl). Unlike hydrazine and alkylhydrazines, hydrazides are nonbasic owing to the inductive influence of the acyl, sulfonyl, or phosphoryl substituent.
A common sulfonyl hydrazide is p-toluenesulfonyl hydrazide, a white air-stable solid. They are also widely used as organic reagents.
Toluenesulfonyl hydrazide is used to generate toluenesulfonyl hydrazones. When derived from ketones, these hydrazones participate in the Shapiro reaction[2] and the Eschenmoser–Tanabe fragmentation.[3] [4]
2,4,6-Triisopropylbenzenesulfonylhydrazide is a useful source of diimide.[5]
Acylhydrazines are derivatives of carboxylic acids, although they are typically prepared by the reaction of esters with hydrazine:
An applied example is a synthesis of sunitinib begins by mixing 5-fluoroisatin slowly into hydrazine hydrate.[6] 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.