摘要:
O-Peracetylated or -perbenzoylated C-(1-bromo-1-deoxy-D-glycopyranosyl)formamides of D-gluco, D-galacto, and D-arabino configuration were reacted with Ag(I)-salts or HgO in nitrile solvents to give N-acyl-1-cyano-D-glycopyranosylamines with an axial C-N bond at the anomeric centre. In the presence of HgBr2, Hg(CN)(2), or InCl3 the anomer of the above glycosylamine with an equatorial C-N bond was also isolated or detected. In CH3NO2 solutions as few as 5-10 equiv of the nitrile were sufficient to get acceptable yields for the products. Under similar conditions N-substituted C-(2,3,4,6-tetra-O-acetyl-1-bromo-1-deoxy-beta-D-galactopyranosyl)formamides gave anomeric spiro-oxazoline derivatives which, upon mild acidic hydrolysis, opened up to di- and tripeptides of anomeric alpha-amino acids. (C) 2011 Elsevier Ltd. All rights reserved.