ACETONATION OF D-TALSOE

The acetonation of α-D-talopyranose in the presence of anhydrous copper(II) sulphate and sulphuric acid has been re-examined, and the major products have been shown to be 2,3:5,6-di-O-isopropylidene-α-D-talofuranose (1, 28%) and 1,2:5,6-di-O-isopropylidene-β-D-talofuranose (2, 10%). These structures were allocated primarily on the basis of mass spectrometry and nuclear magnetic resonance spectroscopy. Oxidation of diacetal 1 with acetic anhydride in methyl sulphoxide gave 2,3:5,6-di-O-isopropylidene-D-talono-1,4-lactone (4). 1,2:5,6-Di-O-isopropylidene-3-O-toluene-p-sulphonyl-β-D-talofuranose (3) was obtained on sulphonylation of diacetal 2. © 1969.