A New Approach to Some 1,6-Dideoxy 1,6-Epithio Sugars

Abstract

The treatment of hexopyranosyl bromides, also activated at C6 (Br, OTs, OMs), with H₂S/HCONMe₂ under basic conditions gives rise to 1,6-dideoxy 1,6-epithio sugars. One such sugar has been further transformed into the synthetically useful 3,4-anhydro-1,6-dideoxy-1,6-epithio-β-D-galactose. The treatment of this epoxide with sodium azide and with cyclohexylamine is described. An analogous treatment of one doubly activated hexopyranosyl bromide with sodium hydrogen selenide has led to a novel 1,6-dideoxy 1,6-episeleno sugar which displayed interesting n.m.r. spectra. Finally, in an attempt to prepare 1,6-dideoxy 1,6-epidithio sugars, a tetraalkylammonium tetrathiomolybdate reagent was found to be the reagent of choice for converting doubly activated hexopyranosyl bromides into 1,6-dideoxy 1,6-epithio sugars.