Mass spectra of 1,2,4‐triazoles—II: Alkyl 1,2,4‐triazoles

The mass spectra of monomethyl 1,2,4‐triazoles contain fragment ions produced by specific cleavage of the heterocyclic ring. A major fragmentation from many molecular ions involves the elimination of HCN, but loss of N2 is either very small or completely absent. No N or H scrambling occurs within the triazole ring system, as evidenced by labelling studies. The loss of a hydrogen atom from the molecular ions of 3‐alkyl‐1,2,4‐triazoles (alkyl ⩾ C2H5) originates from hydrogens attached to the β carbon and nitrogen atoms.