Acetic Anhydride → HCID 13191409, compound

Participants

Reaction Steps

A solution of benzyl 2-acetamido-4-O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside (2.1 g, 2.3 mmol) in methanol (80 ml) and n-butylamine (20 ml) is heated for 48 hours at reflux temperature. Cooling and evaporation of the reaction mixture gives a solid that is slurried in water and lyophilized. The resulting solid is dissolved in the minimal volume of N,N-dimethylformamide and the solution applied to a column of silica gel (E. Merck, No. 7734, 70-230 mesh). Elution with 20:1 chloroform-methanol and evaporation of the appropriate fractions gives a chromatographically homogeneous solid that is dissolved in methanol (35 ml) and treated with acetic anhydride (2.5 ml) for 2 hours at room temperature. Evaporation of the reaction mixture and several coevaporations with toluene gives a solid that is crystallized from ethanol to afford pure benzyl 2-acetamido-4-O-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside; yield 1.1 g (69%), m.p. 252°-256° (dec.), [α]D25 +72° (c, 1.2, methanol). The 300-MHz nmr spectrum in methanol-d4 is in accord with the desired structure.

Provenance & Evidence