New reactions of Hünig's base with S2Cl2: formation of monocyclic 1,2-dithioles

Systematic variation of the ratio of Hünig's base 1 to S₂Cl₂ in their reactions in chloroform shows that, in addition to known tricyclic bisdithiolothiazine thiones 4 and 5, monocyclic dithiole-3-thiones 6 and 7 can be isolated; when the inert base DABCO is added the extent of sulfuration of the products is reduced and thiones are replaced by their oxo analogues, and diisopropylamines 15 are converted into monocyclic dithiol-3-ones 16; an overall mechanistic rationalisation of the results, extending earlier work, is presented.