Reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates in the presence of 5,5-diaryl thiohydantoins. Synthesis of functionalized imidazo[2,1-b][1,3]thiazines

The reaction of stoichiometric amounts of dialkyl acetylenedicarboxylates with alkyl isocyanides in the presence of 5,5-diaryl thiohydantoins afforded imidazo[2,1-b][1,3]thiazines in good overall yields.