ALPHA-AMINO OR BETA-AMINO POLYHYDROXY ACIDS FROM THE REACTION OF BROMODEOXYALDONOLACTONES WITH LIQUID-AMMONIA

Reaction of 2-bromo-2-deoxy-L-threono- (1) or -D-xylono-1,4-lactone (4) with liquid ammonia, gives 3-amino-3-deoxy-D-threonic- (3a) and -D-arabinonic acid (6a), respectively. The latter (6a) could be converted into the hydrochloride of 3-amino-3-deoxy-D-arabinono-1,4-lactone 7). The 2,5-dibromo-2,5-dideoxy-D-xylono-1,4-lactone (13) yielded 2,5-diamino-2,5-dideoxy-D-xylono-1,5-lactam (21) with liquid ammonia. This was also obtained from 2,5-dibromo-2,5-didexy-D-lyxonolactone (14) under similar conditions. In both reactions varying amounts of the C-2 epimeric 2,5-diamino-2,5-dideoxy-D-lyxono-1,5-lactam (20) were formed, owing to base-catalysed epimerisation. By monitoring the reaction of 2-bromo-2-deoxy-as well as of 2,5-dibromo-2,5-dideoxyaldonolactones with aqueous ammonia by C-13-NMR spectroscopy, it was shown that 2,3-epoxy carboxamides were intermediates. The 2,3-epoxy function in L-erythro-(2) and D-lyxo-(5) epoxy carboxamides were stable in aqueous ammonia, while the cyclic 2,3-epoxy-D-lyxono-lactam (17) opened at C-2 within 20 h to give 21.