Mass spectral fragmentation thiols

Physical Properties of 1,3,4-Thiadiazoles. Ultraviolet spectra of some 2-benzylideneamino-5-phenyl-1,3,4-thiadiazoles have been reported. The n.m.r. spectral properties and conformational preferences of some open-chain and cyclic aromatic sulphides that contain 1,3,4-thiadiazole units, spectroscopic data of metal (Mn, Fe, Co, Ni, Cu, or Zn) chelates of iV-(5-phenyl-l,3,4-thiadiazol-2-yl)dithiocarbamic acids, conductometric and i.r. and Raman determinations on thirteen complexes of Zn, Cd, or Hg with 2-methyl-5-mercapto-1,3,4-thiadiazole, and thermogravimetry of some noble- and common-metal chelates of 5-amino-l,3,4-thiadiazole-2-thiol were also described, as well as the mass-spectral fragmentation of 2-phenyl-... 

Pappalardo and co-workers studied the mass spectral characteristics of alkyl and aryl substituted 2,5-dithio-1,3,4-thiadiazoles. Selected ions in the mass spectra of SH, S-CH3, and S-aryl thiadiazoles were tabulated. The S-aryl thiadiazoles form stable cyclic ions yielding additional fragments. The fragmentation pattern is dependent on the structural characteristics of the substituents. If both tautomers—thiol and thione—are present, the molecular ion will also lose CS2. Besides the base peak, intense peaks observed in the MS spectrum are due to extensive fission of the thiadiazole ring. Some of the fragments formed are shown in Scheme 4 <820MS(17)335). 

---