SYNTHESIS OF 1,6-ANHYDRO DERIVATIVES OF 2-AMINO-2-DEOXY-BETA-D-TALOPYRANOSE AND 4-AMINO-4-DEOXY-BETA-D-TALOPYRANOSE

The oxime (2) of 1,6-anhydro-3,4-O-isopropylidene-β-D-lyxo-hexopyranos-2-ulose (1) in aqueous hydrochloric acid is reduced stereospecifically by hydrogen and a platinum catalyst, with concomitant hydrolysis of the O-isopropylidene group, to give 2-amino-1,6-anhydro-2-deoxy-β-D-talopyranose hydrochloride (3) in high yield. Hydrolysis of the anhydro sugar 3 under more vigorous conditions gave crystalline 2-amino-2-deoxy-α-D-talopyranose hydrochloride (4). In aqueous solution, the amino sugar 4 exists as a 1:2 mixture of the α and β-D-pyranose anomers. Reduction of 1,6-anhydro-2,3-O-isopropylidene-β-D-lyxo-hexopyranos-4-ulose oxime (5) in aqueous hydrochloric acid, with hydrogen over platinum, also occurred stereospecifically, to give a crystalline product formulated as 4-amino-1,6-anhydro-4-deoxy-β-D-talopyranose hydrochloride (6), which was further characterized as the peracetylated derivative 7. Attempted hydrolysis of 6 to give 4-amino-4-deoxy-D-talose hydrochloride (8) gave only unchanged 6 and tarry products, presumably because the free 4-amino sugar derivative 8 undergoes rapid destruction in the acid solution by way of a pyrrole derivative. © 1968.