The loss of amine from electron ionized large-ring cycloalkylamines

Large‐ring ionized cycloalkylamines of low internal energy lose ammonia and homologous alkyl radicals competitively. It is shown by deuterium‐labelling experiments, that ammonia is lost mainly after ring‐contraction of the original parent ion to an alkyl‐monosubstituted cyclohexylamine isomer. This fragmentation is preceded by abundant hydrogen exchanges occurring mainly in this rearranged structure, but also, for the largest ring compounds, to some extent in the original structure.