MASS SPECTRA OF SULFUR COMPOUNDS. ASSESSMENT OF 1, X (X=2,3,4,5) HYDROGEN TRANSFER IN DIALKYL SULFIDES AND DISULFIDES UNDER ELECTRON IMPACT. A NOVEL 1,5-H SHIFT

Abstract

The transfer of hydrogen atoms from the gamma carbon of dialkyl disulfides upon electron impact is presented and its occurrence is formally shown by the electron ionization mass spectrum of 1-(2′,2′-dideuteriocyclohexyl)-2,3-dithiapent-1,1′-ene (4b). Also, the spectrum of 1-(2′,2′-dideuteriocyclohexyl)-2-thiahex-1-ene (3b) is analyzed in terms of hydrogen/deuterium transfer, where it is absent. This result is compared with selected mass spectral data of eighteen other dialkylthianes. Evidence is put forth to indicate that dialkyl sulfides are prone to undergo only 1,3-H shift upon electron inpact, whereas in dithianes 1,3- and 1,5-Hydrogen transfer take place. The evidence collected suggests that neither 1,2- nor 1,4-hydrogen transfer occurs in both sulfur derivatives.