Syntheses of derivatives of lacto-<i>N</i>-biose. I. 4,6-Di-<i>O</i>-acetyl-3-<i>O</i>-(tetra-<i>O</i>-acetyl-β-<scp>D</scp>-galactopyranosyl)-2-deoxy-2-phthalimido-α,β-<scp>D</scp>-glucopyranosyl chloride

Abstract

Procedures are reported for the synthesis of 4,6-di-O-acetyl-3-O-(tetra-O-acetyl-β-D-galactopyranosyl)-2-deoxy-2-phthalimido-α,β-D-glucopyranosyl chloride, a reagent useful for the reliable introduction of β-D-Galp-(1 → 3)-β-D-GlcNAcp units (lacto-N-biose 1 units) into oligosaccharide structures. A benzyl glycoside intermediate is hydrogenolyzed to the alcohol which is subsequently converted to the glycosyl chlorides by use of the Vilsmeier reagent in the presence of sym-collidine. A comparison is made of the oxazoline method for the preparation of β-glycosides from 2-amino-2-deoxysugars and the phthalimido procedure developed in this laboratory.