Mass spectrometric fragmentation of the tautomers of 1,3‐diketones. A gas chromatographic/mass spectrometric study

The diketo and ketoenol tautomers of aliphatic 1,3‐diketones can be easily separated by gas chromatography. The mass spectra of tautomers of pentane‐2,4‐diones substituted at C(l) and C(3), separated in this way, have been obtained. The fragmentation mechanisms are discussed. The mass spectra of the tautomers are quite different, and the main fragmentation pathways can be easily linked to the structures of the (non‐interconverting!) tautomeric molecular ions. Furthermore, isomers differing by the position of the substituent can also be identified by their mass spectra.