Mass spectra of some 1,2,4‐thiadiazoles

Abstract
Substituted 1,2,4‐thiadiazoles were found to undergo fragmentation by loss of RCN from the molecular ion with both 3‐ and 5‐substituents being involved to some extent. This was followed by loss of sulfur to yield a nitrilium ion. With 5‐hydrazino substituents, hydrogen transfer was observed from the substituent to a ring nitrogen atom.