Quinazolines. Part X. The fragmentation of quinazolines under electron impact

Abstract

Quinazoline, under electron impact, fragments by the consecutive loss of two molecules of HCN to give a benzyne radical ion. Fragmentation of substituted quinazolines also occurs by this pathway as well as by others normally associated with the breakdown of the substituent. In all cases studied, groups attached to C(4) were lost in preference to those on C(2). Substituents on C(5) or C(8) usually gave rise to abnormal fragmentations involving the peri-positions, C(4) and N(1), respectively.