Studies in mass spectrometry. Part XII. Mass spectra of enamines

Abstract

The mass spectra of enamines derived from aldehydes, cyclic ketones, β-keto-esters, and β-diketones have been studied. Information as regards the branching at the α- or β-carbon atom of an aldehyde can be gained from the mass spectrum of the derived enamine. The position of the alkyl substituent in an alkycylclohexanone can sometimes be inferred from the mass spectrum of the related enamine. The spectrum of ethyl 3-phenylaminobut-2-enoate is noteworthy for the probable occurrence of an intramolecular “acylation” of an aromatic ring which takes place in the mass spectrometer. Some enamines obtained from β-diketones give base peaks due to M– OH ions, and M– O ions are also quite abundant in these spectra.