| 摘要 |
<p>The invention describes a one-pot single step procedure for the azidochlorination or diazidization of glycals, including glycal elements of carbohydrates. Compounds such as 3,4,6-tri-O-benzyl-2-azido-2-deoxy-alpha-D-galactopyranosyl chloride, and 3,4,6-tri-O-benzyl-2-azido-2-deoxy-alpha-,beta-D-galactopyranose are prepared from tri-O-benzyl galactal as well as 3,4,6-tri-O-acetyl-2-azido-2-deoxy-D-alpha-galactopyranosyl chloride and 3,6,-di-O-acetyl-4-O-[2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl]- 2-azido-2- deoxy-alpha-D-glycopyranosyl chloride from their respective O-acetylated glycal derivatives by the addition of azido chloride which is chemically generated in situ. A method using 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galacto-pyranosyl chloride for the synthesis of antigenic determinants such as the terminal asialo GM1(beta-D-Gal (1->3)-beta-D-GalNAc-OR) has been demonstrated. The conversion of the subject synthon into 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosyl bromide and 1,3,4,6-tetra-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranose is also described. A further method for the synthetic generation of the Tn antigen (alpha-D-GalNAc-O-L-serine) is also described.</p> |
