C4H9NO

C4H9NO is the molecular formula for several organic compounds that contain four carbon atoms, nine hydrogen atoms, one nitrogen atom, and one oxygen atom. As a formula, it does not define a single structure; the same composition can correspond to different connectivity patterns, most commonly amides.

Two common acyclic isomers are butanamide (also called butyramide) and 2-methylpropanamide (isobutyramide). Butanamide has the structure CH3-CH2-CH2-CO-NH2, derived from butanoic acid. 2-methylpropanamide has the structure (CH3)2CH-CO-NH2, derived from 2-methylpropanoic acid. In both cases the functional group is the amide (-CONH2), and each molecule contains four carbon atoms, one nitrogen, and one oxygen.

The formula can also accommodate other, less common structures with the same empirical composition, but the two listed above are the principal simple amide representatives for C4H9NO. The molar mass of C4H9NO is approximately 87.12 g/mol. Distinguishing among isomers requires structural characterization techniques such as infrared spectroscopy and nuclear magnetic resonance, which identify functional groups and carbon skeletons.

C4H9NO compounds are used as intermediates in organic synthesis and research contexts, where amide groups serve as building blocks or protective groups.