β-d-Galacto-pyranosyl-(1→4)-2-amino-2-de-oxy-α-d-gluco-pyran-ose hydro-chloride monohydrate (lactosamine)

The title compound, C₁₂H₂₄NO₁₀ ⁺·Cl^-·H₂O, (I), crystallizes in the monoclinic space group P2₁ and exists as a monohydrate of a monosubstituted ammonium chloride salt, with the reducing carbohydrate portion existing exclusively as the α-pyran-ose tautomer. The glycosidic bond geometry in (I) is stabilized by an intra-molecular hydrogen bond and is close to that found in crystalline α-lactose. All heteroatoms except gluco-pyran-ose ring O4 participate in an extensive hydrogen-bonding network, which propagates in all directions in the crystal structure of (I).