Electron Impact (El) Mass Spectral Studies on Pyridyl Thiohydroximic Esters and Their Carbamates

S. K. Raza, A. Khullar, Uma Joshi and D. K. Jaiswal

Defence Research and Development Establishment, Gwalior - 474 002, India.

The electron impact (El) mass spectral studies on pyridyl thiohydroximic esters have shown some interesting fragmentation pathways. The probable mechanism for the formation of some of the salient fragments has been confirmed by performing daughter ion experiments. The daughter ion spectra of methyl and cyclohexyl derivatives exhibited a stepwise Ioss of OH and RN whereas in phenyl derivative a concerted loss of C6H5NOH has been observed to give an ion at m/z 122 from the skeletally rearranged molecular Ion. The methyl and cyclohexyl derivatives also produced an ion at m/z 154 arising due to Mc Lafferty rearrangement The carbamates showed similar fragmentation as their thiohydroximate esters after the initial loss of isocyanates from the molecular ions.

pyridyl thiohydroximic; cyclohexyl derivatives; thiohydroximate esters