Crystal Structure of Methyl 2,3-di-O-benzyl-α-d-(4-2H)-Glucopyranoside

Abstract

Methyl 2,3-di-O-benzyl-α-d-(4-²H)-glucopyranoside, C₂₁H₂₅DO₆, is an intermediate used in synthesis of oligosaccharides. The hexopyranose ring has the ⁴C₁ chair conformation in the crystal structure. The exocyclic groups of the hexose sugar show for the glycosidic torsion angle ϕ =−52.8° and for the hydroxymethyl group the gauche-gauche conformation with ω = −64.7°, one of the two main orientations of the latter group in hexopyranose sugars that have the gluco-configuration, i.e., with an equatorial hydroxyl group at C4. The benzene rings of the benzyl groups are arranged with an angle of 56.9° to each other within the molecule and show intramolecular as well as intermolecular C-H···π interactions. A chain of intermolecular hydrogen bonds exists along the b-axis involving O4 and O6 atoms. The experimentally observed peak in the infrared spectrum at 2159 cm^− 1 was ascribed to the stretching of the C4–D4 bond based on DFT calculations.

Graphical Abstract

In the structure of the monosaccharide methyl 2,3-di-O-benzyl-α-d-(4-²H)-glucopyranoside, C₂₁H₂₅DO₆, the two hydroxyl groups HO4 and HO6 act as both donors and acceptors resulting in an intermolecular hydrogen bond chain along the b-axis direction.