Paper
Branched-chain Sugars. IX. Reaction of 3,6-Anhydro-1,2-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose with Nitromethane or Hydrogen Cyanide
Published May 1, 1977 · Ken-Ichi Sato, J. Yoshimura, C. Shin
Bulletin of the Chemical Society of Japan
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Abstract
3,6-Anhydro-1,2-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (2) was converted into 5,6-di-O-acetyl-1, 2-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (5) by the protection of the carbonyl function with hydroxylamine, followed by acetylation and removal of the protecting group with chromium(II) acetate. Nitromethane condensation of 2 and 5 at room temperature gave the corresponding 3-nitromethyl derivatives having D-gluco- and D-allo-configuration, respectively. The difference in the stereoselectivity was explained by the easiness of isomerization of the initial product to thermodynamically stable epimer, because the reaction temperature was essential to control the selectivity in the same reaction of 1,2 : 5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose. Reaction of 2 with hydrogen cyanide in dry pyridine followed by acetylation gave the corresponding 3,5,6-tri-O-acetyl-3-cyano derivative of D-allo-type, whereas, the reaction in water gave instantly 3-(hydroxycarbonimidoyl)-1,2-O-isopropylidene-α-D...
Nitromethane condensation of 2, 5,6-di-O-acetyl-1, 2-O-isopropylidene--D-ribo-hexofuranos-3-ulose (5) at room temperature gave 3-nitromethyl derivatives with D-gluco- and D-allo
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