A multicomponent access to 1,3-thiazine-6-phenylimino-5-carboxylates

The multicomponent reaction of ethyl 3-aminocrotonate (1), substituted phenylisothiocyanates (2a–i) and acetic anhydride (7), afforded facile access to a series of substituted 1,3-thiazine-6-phenylimino-5-carboxylates under mild conditions in 15–65% yields. Limited tolerance for modification of the anhydride moiety was noted with a significant reduction in yield for propionic and trifluoroacetic anhydrides. The use of benzoic anhydride favoured a two-component coupling product.