Dithians, 1,4-Dithiepans, and 5- Dithiocans

4-dithian having only the hydrogen atoms a to one of the sulphur atoms exchanged for deuterium. Thus ring opening to (123) occurred prior to 

4-dithian. A similar initial fragmentation of (122) took place in the presence pf pyridine but further reaction of (123) with pyridine occurred mainly at C-2, and resulted in the formation of open-chain products. An X-ray structure determination of (122) showed D,h symmetry in which the S—S bond distance (3.13 A) is significantly less than the van der Waals S-S separation. Thermolysis in diphenyl ether, or photolysis at high concentration in acetonitrile, of exo-2,3-epithionorbom-5-ene yielded some 1,4-dithian (124) via dimerization of the biradical generated by carbon-sulphur bond cleavage. 

4 Compounds containing Three or Mrnre Snlfrtiur Atoms 

Chlorination of 1,3,5-trithian in acetic acid-water mixtures proceeded via a series of intermediates, among them bischloromethyl sulphide, to 

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