Reaction of trithiazyl trichloride with alkenes and alkynes

Abstract

Alkenes and alkynes react readily with trithiazyl trichloride 1 to give 1,2,5-thiadiazoles 2 in one step. Thus 3-amino-1,2,5-thiadiazole 5 is now readily available from N-vinylphthalimide and 1 in two steps. Cyclic alkenes react similarly to give fused thiadiazoles (7, 12) and phenanthrene gives the phenanthrothiadiazole 16. Tetra-substituted alkenes such as 13 appear to give the analogous 3,4-dihydrothiadiazoles (e.g. 14) which spontaneously ring open to give readily hydrolysed bis(methyleneamino) sulfides (e.g. 15). A simple set of mechanisms is proposed for all of these reactions.