Dualorthointeraction in 2‐substituted‐3‐(2‐methylphenyl)‐4(3H)‐quinazolinones and their thio analogues under electron impact conditions

Abstract

AbstractCompetingorthointeractions, involving the CX and theortho‐methyl substituent on the 3‐phenyl moiety, resulting in the eliminations of˙CH3and˙OH/˙SH from the molecular ions of 2‐substituted‐3‐(2‐methylphenyl)‐4(3H)‐quinazolinones and their thio analogues, were observed. An intramolecular aromatic substitution of the heteroatom of CX at theortho‐carbon of the 3‐phenyl moiety ejecting the methyl group and a hydrogen transfer from the same ortho‐methyl substituent to the heteroatom of CX resulting in the expulsion of˙XH are envisaged for the dualorthointeraction. Another expected fragmentation process observed in these compounds is the transfer of the aryl group from the 3‐position of the heterocycle to the heteroatom of CX leading to the elimination of ArX˙from the molecular ions. The proposed fragmentation processes and the ion structures are supported by high‐resolution data,B/EandB2/Elinked‐scan spectra, collisionally activated decompositionB/Espectra and deuterium isotopic labelling.