Mass spectra of 1‐(2′‐hydroxy‐5′‐alkylphenyl)‐1‐alkanone (<i>E</i>)‐oximes

Abstract

Abstract The mass spectra of 1‐(2′‐hydroxy‐5′‐alkylphenyl)‐1‐ethanone ( E )‐oximes 1–6 and 1‐(2′‐hydroxy‐5′‐methylphenyl)‐1‐alkanone ( E )‐oximes 7–12 are given and the major fragmentation pathways discussed. The simultaneous loss of water and alkyl moieties from the molecular ion indicates that a skeletal rearrangement take place and a cycloheptatrienyloheterocyclic system is formed. The McLafferty rearrangement, γ‐fission in the side aliphatic chain and oxygen expulsion are discussed with evidence being drawn from accurate mass measurements, metastable ions and comparison with mass spectral data of related compounds.