CH3CH2CH2CO
CH3CH2CH2CO commonly denotes the butanoyl (butyryl) acyl fragment, more precisely written CH3CH2CH2C(=O)–. It is the four‑carbon acyl group derived from removal of the hydroxyl hydrogen from butanoic (butyric) acid or from cleavage of a C–O bond in a carbonyl derivative. The group is often encountered as part of larger molecules (for example, butanoyl chloride, esters, amides or thioesters such as butyryl‑CoA) rather than as an isolated neutral species.
Chemically, the carbonyl carbon in the butanoyl group is electrophilic due to resonance and polarization of
Butanoyl-containing structures appear in synthetic organic chemistry, biochemical intermediates (notably butyryl‑CoA), pharmaceuticals and in flavor and