T3P-promoted synthesis of a series of novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones

A series of 11 novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-aryl-C-phenyl imines with thiosalicylic acid. This provides simple and ready access to N-aryl compounds in this family, which have been generally difficult to prepare.