C17H15BrCl2N2O2, monoclinic, P21/c (no. 14), a = 20.333(7) Å, b = 11.226(5) Å, c = 7.843(3) Å, β = 99.651(8)°, V = 1764.8(12) Å3, Z = 4, Rgt (F) = 0.0464, wRref (F 2) = 0.1601, T = 173 K.

The protected glycoside of 2-amino-2-deoxyglucose (glucosamine), namely allyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranoside, C23H25NO10, was synthesized from the glycosyl bromide. Crystallographic analysis confirmed the β-anomeric configuration and showed an approximately orthogonal orientation of the phthalimido group with respect to the pyranose ring. The absolute configuration of the molecule was known from the synthetic route and assigned accordingly.