Spectrometric and theoretical evidences for the occurrence of tautomeric structures of selected ketones

The enolisation degree of ketones is generally favoured by the increase of the steric effect exerted by the substitution or to the carbonyl group. The analysis of the corresponding mass spectra has allowed us to assign unambi guously some fragmentations to specific tautomers and to establish an accep table correlation between the corresponding ion abundance ratios and the AM I MO theoretical calculation of the approximate enolisation equilibrium con stants. (C) 2000 Elsevier Science B.V. AU rights reserved.