S,N Double Rearrangement. 2. X-ray Crystal Structures of Rearranged Products

Article abstract of DOI:10.1021/jo00345a039

Condensation of 2-cyano-3-mercapto-3-(methylthio)acrylamide (1) with benzoic acid in the presence of polyphosphate ester gave 5-carbamoyl-4-(methylthio)-2-phenyl-1,3-oxazine-6-thione (6), which, on treatment with boiling ethanol, was easily converted into 5-carbamoyl-4-(methylthio)-2-phenyl-1,3-thiazin-6-one (9).Reduction of 9 with NaBH4 gave its 2,3-dihydro derivative 10.The strucures of 6,9, and 10 were determined by single-crystal X-ray diffraction.A reaction mechanism of this novel S,N double rearrangement is briefly discussed.