SYNTHESIS OF O-[4,6-DI-O-ACETYL-4-O-(2,3,4,6-TETRA-O-ACETYL-BETA-D-GALACTOPYRANOSYL)-2-DEOXY-2-HYDROXYIMINO-D-ARABINO-HEXOPYRANOSYL]-N-BENZYLOXYCARBONYL-L-SERINE METHYL-ESTERS AND THEIR TRANSFORMATIONS

3,6-Di-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-2-deoxy-2-hydroxyimino-alpha- and -beta-D-arabino-hexopyranosides of N-benzyloxycarbonyl-L-serine methyl ester as well as of ethanol have been synthesised from D-lactal hexaacetate via nitrosyl chloride, followed by condensation with L-serine derivatives and ethanol, respectively. The compounds of L-serine thus obtained were modified at C-2 and C-3 to afford L-serine derivatives attached to disaccharides containing terminal alpha-D-gluco-, 2-acetamido-alpha-D-gluco-, beta-D-manno, 2-acetamido-beta-D-manno-pyranosyl, 3-azido-2-hydroxyimino-alpha-D-arabino-, and alpha-D-ribohexopyranosyl residues.