Divinyl sulfide. 15. Cycloaddition of divinyl sulfide and its 2-methyl derivatives to thiourea and N-monoalkyl- and N-monoarylthioureas
The heterocyclization of divinyl sulfide with N-monoalkyl- and N-monoarylthioureas and 2-vinyl propen-1-yl sulfide and di(propen-1-yl) sulfide with thiourea in the presence of equimolar amounts of inorganic acids leads to new nitrogen heterocycles 2H,6H-2,6-dialkyl-4-alkylamino- and 2H,6H-2,6-dialkyl-4-imino-5-N-phenyl-1,3,5-dithiazines in salt form. The action of bases on the diathiazine salts gives the corresponding 1,3,5-dithiazines. These heterocycles were found more sensitive to the action of nucleophiles causing ring opening than 1,3,5-dithiazines unsubstituted at the nitrogen atom.