Lithium Hydroxide → 2-Bromo-5,6-dichloro-1-β-D-ribopyranosyl-1H-benzimidazole

3.0 g (5.7 mmol) 2-Bromo-5,6-dichloro-1-(2,3,4-tri-O-acetyl-β-D-ribopyranosyl)-1H-benzimidazole was deprotected as using the general procedure summarized in the foregoing description by being dissolved in 60 ml dioxane and the resultant solution cooled in an ice bath between 0 and 5° C. To this solution was added all at once, 22 ml (22 mmol) of 1M aq. LiOH. The mixture was removed from the ice bath and allowed to stir at ambient temperature for 1 h. The mixture was diluted with 120 ml of pH 7 phosphate buffer and extracted with ethyl acetate. The ethyl acetate layer was dried over magnesium sulfate (anhyd.), filtered and solvents evaporated. The residue was triturated in dichloromethane and 1.7 g (4.3 mmol, 75% yield) of 2-bromo-5,6-dichloro-1-β-D-ribopyranosyl-1H-benzimidazole was collected by vacuum filtration. The product was dried in a vacuum oven at 50° C. overnight; m.p. 175° C. (decomposes); 1H NMR (DMSO-d6) δ 7.96 (s, 1H), 7.07 (s, 1H), 5.64-5.62 (d, J=9.2 Hz), 5.19-5.17 (d, 1H, J=6.4 Hz), 5.13-5.12 (d, 1H, J=3.2 Hz), 4.86-4.84 (d, 1H, J=6.5 Hz), 4.12-4.06 (m, 1H), 3.98-3.92 (m, 2H), 3.68-3.63 (m, 2H).

1. customThe mixture was removed from the ice bath
2. additionThe mixture was diluted with 120 ml of pH 7 phosphate buffer
3. extractionextracted with ethyl acetate
4. dry with materialThe ethyl acetate layer was dried over magnesium sulfate (anhyd.)
5. filtrationfiltered
6. customsolvents evaporated
7. customThe residue was triturated in dichloromethane

ORD record

ord-725fb19741e0465ab86fff30c8f32ae7

Source dataset

uspto-grants-2010_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07858773B2