alpha-Amino Polyhydroxy Tetronic and Pentonic Acids from Bromodeoxyaldonolactones.

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Abstract
Treatment of either 2-bromo-2-deoxy-L-threono- (3) or L-erythrono-1,4-lactone (6) with NaN3 gave identical mixtures of 2-azido-2-deoxy-L-threono- (7) and -L-erythronolactone (8). Similar treatment of 2-bromo-2-deoxy-D-xylono-1,4-lactone (13) gave a 1:1 mixture of 2-azido-2-deoxy-D-xylono- (15) and -D-lyxono-1,4-lactone (16), while the 2-bromo-2-deoxy-D-arabinono-1,4-lactone (24) gave a 1:1 mixture of 2-azido-2-deoxy-D-arabinono- (26) and D-ribono-1,4-lactone (27). All isomers could be separated by either flash chromatography or crystallization. Catalytic hydrogenation of the azido lactones gave the corresponding amino lactones, as hydrochlorides, or the .alpha.-amino acids. The azido lactone15 was converted into 2-acetamido-2-deoxy-D-xylose (21), while 26 gave 2-amino-2-deoxy-D-arabinose .cntdot. HCl (35). The epidermic mixtures of azido lactones (15,16) or (26,27) were converted in a one-pot synthesis into 2-acetamido-5-O-acetyl-2,3-dideoxy-D-threo-pentono-1,4-lactone (37). The intermediate was shown to be 2-acetamido-5-O-acetyl-2,3-dideoxy-D-glycero-pent-2-eno-1,4-lactone (36), which was prepared from the fully acetylated amino lactones (32, 33). The 2-bromo lactones, as well as the 2-azido lactones, were shown to equilibrate under basic conditions.