Improved Method of Preparation of Glycosylmethylamines

As shown especially for the transformation of the thermally rather unstable α-D-galactofuranosylnitromethane to α-D-galactofuranosylmethylamine, the electron-transfer reduction of glycosylnitromethanes with ferrous ions in aqueous ammonia at room temperature is a very mild and convenient alternative of the preparation of the corresponding glycosylmethylamines. Also βL-rhamnopyranosylmethylamine, β-D-mannopyranosylmethylamine, β-D-galactopyranosylmethylamine, β-D-glucopyranosylmethylamine, and 2-acetamido-2-deoxy-β-D-glucopyranosylmethylamine were prepared by this improved method. Due to a simple isolation procedure the method gives 90— 95 % yields of these interesting C-glycosyl compounds containing no isomeric products detectable by H NMR spectroscopy. A preparation of β-L-rhamnopyranosylnitromethane is also described.