Hydrogen Bromide → Tri-O-acetyl-D-glucal

Participants

Reaction Steps

Glucose (1.000 g) was suspended in a solution of acetic acid (10 mL) and acetic anhydride (3.606 g, 7.0 equiv) and 1.000 g 31% HBr/acetic acid solution added. The reaction mixture was allowed to stir for 1 h, after which 9.000 g more 31% HBr/acetic acid solution (total of 7.7 equiv HBr) was added and allowed to stir overnight. Sodium acetate was then added (2.700 g) to neutralized the excess HBr, and the reaction mixture was added to a suspension containing pulverized CuSO4 ·5H2O (0.315 g), zinc (12.600 g), water (10 mL), sodium acetate (9.450 g), and acetic acid (5 mL) and the resultant reaction mixture was stirred vigorously for 1.5 h. The solution was then filtered and the solid washed with ethyl acetate (100 mL) and water (100 mL). The organic layer of the filtrate was then washed with NaHCO3 (100 mL) and brine (50 mL), dried (Na2SO4), filtered and the solvent removed under reduced pressure to provide tri-O-acetyl-D-glucal (1.350 g, 98%) as a colorless oil free of impurities as judged by 1H NMR.

Provenance & Evidence