Hydrogen Bromide → alpha-D-Glucopyranosyl bromide, tetraacetate

Reaction equation

C(O[C@H:5]1[O:22][C@H:21]([CH2:23][O:24][C:25](=[O:27])[CH3:26])[C@@H:16]([O:17][C:18](=[O:20])[CH3:19])[C@H:11]([O:12][C:13](=[O:15])[CH3:14])[C@H:6]1[O:7][C:8](=[O:10])[CH3:9])(=O)C.[BrH:28].C(OCC)(=O)C.CCCCCC>ClCCl>[C:8]([O:7][C@@H:6]1[C@@H:11]([O:12][C:13](=[O:15])[CH3:14])[C@H:16]([O:17][C:18](=[O:20])[CH3:19])[C@@H:21]([CH2:23][O:24][C:25](=[O:27])[CH3:26])[O:22][C@@H:5]1[Br:28])(=[O:10])[CH3:9]

Participants

Procedure

1,2,3,4,6-penta-O-acetyl-α-D-glucopyranose (1.0 g, 2.60 mmol) was dissolved in 20 mL of dichloromethane and 1.90 mL of hydrobromic acid (33% in acetic acid) at 0° C., and the reaction was stirred while warming to room temperature. TLC (40% ethyl acetate-hexane) after 18 h showed complete consumption of the starting material and formation of a higher running spot. The reaction was slowly diluted with saturated sodium bicarbonate (25 mL), extracted into dichloromethane (2×100 mL), dried over sodium sulfate, filtered and concentrated to afford 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide which was used without purification.