Chemistry:Hydrazide

Short description: Class of chemical compounds

Hydrazides in organic chemistry are a class of organic compounds with the formula R–NR1
–NR2
R3
where R is acyl (R'–C(=O)–), sulfonyl (R'–S(=O)
2–), phosphoryl ((R'–)
2P(=O)–), phosphonyl ((R'–O–)
2P(=O)–) and similar groups (chalcogen analogs are included, for example sulfur analogs called thiohydrazides), R1
, R2
, R3
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.

Sulfonyl hydrazides

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 and the Eschenmoser–Tanabe fragmentation.

2,4,6-Triisopropylbenzenesulfonylhydrazide is a useful source of diimide.

Acyl hydrazides

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

Acylhydrazines are derivatives of carboxylic acids, although they are typically prepared by the reaction of esters with hydrazine:

Use

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.

See also

• hydrazide imide - tautomeric form of amidrazone