O-(2-Acetamido-3,4,6-tri-O-acetyl-2-desoxy-β-D-glucopyranosyl)-(1->2)-O-<(2-acetamido-3,4,6-tri-O-acetyl-2-desoxy-β-D-glucopyranosyl)-(1->6)>-1,3,4-tri-O-acetyl-D-mannopyranose