Mass Spectrometric Studies. XIV. Nitrochalcones

Abstract

The mass spectra of chalcone, of its 2-, 2'-, 3-, 3'- and 4-nitro derivatives, and of a number of deuterated analogues, are described. Fragmentation of the 2-nitro isomer is very simple on account of anchimeric assistance to a carbon-carbon bond fission from the nitro group. The 2'-nitro isomer shows complex fragmentation resulting from oxygen transfer to the α,β-double bond. The 3-, 3'-, and 4-nitro compounds fragment in ways similar to that of chalcone itself, except for losses of hydroxy groups from their molecular ions. The origins of the transferred hydrogen atoms are shown by labelling experiments, and structures are suggested for the ions formed.