Synthesis of benzyl 2-azido-2-deoxy-4-O-β-d-glucopyranosyl-α-d-glucopyranoside and 1,6-anhydro-2-azido-2-deoxy-4-O-β-d-glucopyranosyl-β-d-glucopyranose

The title compounds were prepared from cellobiose by means of two series of transformations. One series entailed the azidonitration of 3,6-di-O-acetyl-1,5-anhydro-2-deoxy-4-O-(2,3,4,6-tetra-O-acetyl-β-d- glucopyranosyl)-d-arabino-hex-1-enitol to give 3,6-di-O-acetyl-2-azido-2-deoxy-4-O-(tetra-O-acetyl-β-d-glucopyranosyl)-β-d-glucopyranosyl nitrate, which was then converted into the benzyl α-glycoside. Minor by-products of the azidonitration reaction were also identified. For the second synthesis, 1,6-anhydro-β-cellobiose was converted into 1,6-anhydro-4-O-(4,6-O-isopropylidene-β-d-glucopyranosyl)- β-d-glucopyranose (15). The azido function was then introduced at the C-2 position of the 1,6-anhydro residue, by a displacement reaction involving the 2,3-anhydro-d-manno analog of 15 as an intermediate compound.