benzyl 2-acetamido-4-O-(2'-acetamido-2'-deoxy-3',4',6'-tri-O-acetyl-β-D-glucopyranosyl)-2-deoxy-3,6-di-O-acetyl-β-D-glucopyranoside

heptaacetylchitobiosyl chloride

heptaacetylchitobiosyl bromide