反应详情

2,3,4,6-Tetra-O-benzyl-D-galactopyranose (107 g) was dissolved in ethanol (0.6 L) and, whilst stiffing at 0° C., sodium borohydride (31 g) was added. After stiffing overnight TLC analysis indicated completion of the reaction. The ethanol solution was partitioned between water (3 L) and ether (1.5 L). The organic phase was dried (Na2SO4), filtered and concentrated. The resulting oil was purified by flash chromatography (gradient elution using 20→50% ethyl acetate/petroleum ether) and then crystallised from a mixture of ethyl acetate/petroleum ether to give 2,3,4,6-tetra-O-benzyl-D-galactitol (97 g, 91%) as a white solid. 1H NMR (CDCl3): δ 2.4 (1H, bs), 3.35 (1H, bs), 3.55 (2H, m), 3.8 (3H, m), 3.9 (2H, m), 4.1 (1H, m), 4.4-4.8 (8H, m, OCH2Ph), 7.2-7.4 (20H, m, ArH). Mass spectrum: m/z 543 (M+H)+565 (M+Na)+.

1. customwhilst stiffing at 0° C.
2. customcompletion of the reaction
3. customThe ethanol solution was partitioned between water (3 L) and ether (1.5 L)
4. dry with materialThe organic phase was dried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated
7. customThe resulting oil was purified by flash chromatography (gradient elution using 20→50% ethyl acetate/petroleum ether)
8. customcrystallised from a mixture of ethyl acetate/petroleum ether