GAS-CHROMATOGRAPHY MASS-SPECTROMETRY OF THE STEREOISOMERS OF HETEROCYCLIC-COMPOUNDS .1. PERHYDROTHIOXANTHENES

A gas chromatographic-mass spectrometric study of a mixture of the stereoisomers of perhydrothioxanthene has been carried out. Separation was accomplished on columns filled (HT GTCB) with hydrogen treatment-graphitized thermal carbon black and on WCOT capillary columns. The stereospecific features of the retention and the fragmentation of the six stereoisomers under electron impact have allowed the identification of all of them; five of these were previously unknown. The fragmentation of trans-fused stereoisomers is characterized by predominant cleavage of middle-ring bonds, while the fragmentation of cis-fused stereoisomers proceeds through the cleavage of side-ring bonds.