Addition reactions of heterocyclic compounds. Part XXXII. The mass spectra of some azepines obtained from dimethyl acetylenedicarboxylate

Abstract

The fragmentation patterns of a number of fused azepines possessing four ester groups have been measured. When the arrangement of these groups permitted, expulsion of methyl acrylate and the formation of an indolizinium-type cation occurred, but where a corresponding expulsion of methyl maleate or fumarate was the only possibility it did not take place.