Chloride → HCID 13191407, compound

Participants

Reaction Steps

To a solution of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside [prepared by the process set forth in J. C. Jacquinet, et al., Carbohydr. Res., 38, 305 (1974)] (2.95 g, 6.00 mmol), silver trifluoromethanesulfonate (triflate) (1.90 g, 7.39 mmol), and 2,4,6-collidine (0.90 g, 7.42 mmol) in dry nitromethane (45 ml) stirred at room temperature under an atmosphere of nitrogen is added a solution of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl chloride [prepared by the process set forth in S. Akiya et al., Chem. Pharm. Bull., 8, 583 (1960)](3.35 g, 7.38 mmol) in dry nitromethane (45 ml). After stirring for 6 hours at room temperature, additional chloride (1.73 g, 3.81 mmol), silver triflate (0.98 g, 3.81 mmol), and collidine (0.46 g, 3.80 mmol) are added, and stirring is continued overnight with exclusion of moisture. The mixture is then diluted with chloroform (150 ml), undissolved solids removed by filtration, and the filter washed with chloroform (60 ml). The combined filtrates are washed successively with cold water, 3% aqueous hydrochloric acid, saturated aqueous sodium bicarbonate, and water. The dried (sodium sulfate) organic solution is evaporated and the resulting syrup is treated for 6 hours with acetic anhydride (30 ml) and pyridine (40 ml). The mixture is then evaporated and coevaporated several times with toluene. The residue is dissolved in the minimal volume of dichloromethane and the solution applied to a column of silica gel (E. Merck, No. 7734, 70-230 mesh) (900 g packed as a slurry in 9:1 dichloromethane-diethyl ether). Elution with 90:10:0.25 dichloromethane-diethyl ether-methanol and evaporation of the appropriate fractions affords 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 as an amorphous solid; yield 2.17 g (39.8%), [α]D25 +57.1° (c, 1, chloroform). The 300-MHz nmr spectrum in chloroform-d is in accord with the desired structure.

Provenance & Evidence