Reaktion von 3‐(Dimethylamino)‐2 H ‐azirinen mit 1,3‐Thiazolidin‐2‐thion

Reaction of 3‐(Dimethylamino)‐2 H ‐azirines with 1,3‐Thiazolidine‐2‐thione Reaction of 3‐(dimethylamino)‐2 H ‐azirines 1 and 1,3‐thiazolidine‐2‐thione ( 6 ) in MeCN at room temperature leads to a mixture of perhydroimidazo[4,3‐ b ]thiazole‐5‐thiones 7 and N ‐[1‐(4,5‐dihydro‐1,3‐thiazol‐2‐yl)alkyl]‐ N ′, N ′‐dimethylthioureas 8 ( Scheme 2 ), whereas, in i‐PrOH at ca. 60°, 8 is the only product ( Scheme 4 ). It has been shown that, in polar solvents or under Me 2 NH catalysis, the primarily formed 7 isomerizes to 8 ( Scheme 4 ). The hydrolysis of 7 and 8 leads to the same 2‐thiohydantoine 9 ( Scheme 3 and 5 ). The structure of 7a, 8c , and 9b has been established by X‐ray crystallography ( Chapt. 4 ). Reaction mechanisms for the formation and the hydrolysis of 7 and 8 are suggested.