Synthesis and Reactions of Branched‐chain Anhydrouloses with Push Pull Functionality

The α-oxoketene dithioacetal 1 was demethylthiolated with sodium borohydride to give the branched chain anhydroulose 2 which yielded with amines the corresponding aminomethylene enuloses 3, 4 and 5. The heterocyclic anellated pyranose derivatives 6, 7 and 8 were prepared by reaction of 2 with hydrazine hydrate, methylhydrazine and hydroxylamine, respectively. By treatment of methylthiomethylene enulose 18 with guanidine, acetamidine and benzamidine the pyrimidoanellated pyranose derivatives 12—14 have been obtained.