Synthesis and reactions of branched-chain anhydrouloses with push-pull functionality

The alpha-oxoketene dithioacetal 1 was demethyl-thiolated with sodium boroh ydride to give the branched chain anhydroulose 2 which yielded with amines the corresponding aminomethylene enuloses 3, 4 and 5. The heterocyclic anel lated pyranose derivatives 6, 7 and 8 were prepared by reaction of 2 with h ydrazine hydrate, methylhydrazine and hydroxylamine, respectively. By treat ment of methylthiomethylene enulose 18 with guanidine, acetamidine and benz amidine the pyrimidoanellated pyranose derivatives 12-14 have been obtained .