Mass spectra of some 1‐(6′‐substituted‐4′‐methyl‐2′‐quinolyl)‐3‐methylpyrazol‐5‐ols and their 4‐substituted analogues

Electron impact induced fragmentation of some 1‐(6′‐substituted‐4′‐metbyI‐2′‐quinolyI)‐3‐methylpyrazoI‐5‐ols follows a route where the pyrazole moiety is preferentially cleaved with successive losses of two moieties of 41 u. High‐resolution measurements have established that the first loss is due to the Ċ 2 HO moiety, which necessitates an intramolecular hydrogen transfer followed by ring fission. The resultant ion loses CH 3 CN in a subsequent step. The origin of many fragment ions was traced with the use of B/E linked‐scan spectra.