DECOMPOSITION REACTIONS OF AMINO-SUGARS - DEHYDRATION OF 2-AMINO-2-DEOXY-D-GLUCOSE

The stability of the title compound (1) was investigated at 100° in acidified aqueous solutions containing, in some instances, glycine or pyridine. In strong acid (3M hydrochloric acid), the sugar was relatively stable, and no identifiable decomposition-products were observed. In less-acidic solutions (≤0.5M hydrochloric acid) in the presence of glycine, substantial decomposition occurred with the production of 5-(hydroxymethyl)-2-furaldehyde (2) in 0.5-5.2% yield. The major dehydration products, however (up to 18% of the starting sugar), were pyrazine derivatives bearing dissimilar, four-carbon, acyclic-sugar side-chains attached to C-2 and C-5 of the ring, respectively, arising, most probably, from C-3-C-6 of the original sugar molecules. When the conversions were performed in deuterium oxide solution, carbon-bound isotope was observed in 2 (at the aldehyde carbon and at C-3) and, in the pyrazine derivatives, on the ring (positions 3 and 6), and on the sugar-derived, side-chains. © 1979.