反应详情

To a suspension of L-(−)-xylose (133, 19.15 g, 127.5 mmol) and MgSO4 (30.72 g, 255.0 mmol) in acetone (190 mL) was added conc. H2SO4 (1.9 mL) at room temperature. After 12 h, the reaction mixture (all L-(−)-xylose had been consumed) was filtered and the collected solids were washed with acetone (twice, 20 mL per wash). The stirring yellow filtrate was neutralized with NH4OH solution to pH≈9. The suspended solids were removed by filtration. The filtrate was concentrated to afford crude bis-acetonide intermediate as yellow oil. The yellow oil was suspended in water (5 mL), and then the pH was adjusted from 9 to 2 with 1 N HCl in water solution. The reaction mixture was stirred for 12 h at room temperature. The resulting mixture was neutralized by the addition of 25% (w/w) K3PO4 in water until pH≈7. The mixture was extracted with EtOAc. The organic layer was dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel column chromatography to provide the title compound (12.63 g, 52%) as yellow oil.

1. customthe reaction mixture (all L-(−)-xylose had been consumed)
2. filtrationwas filtered
3. washthe collected solids were washed with acetone (twice, 20 mL
4. washper wash)
5. customThe suspended solids were removed by filtration
6. concentrationThe filtrate was concentrated
7. customto afford crude bis-acetonide intermediate as yellow oil
8. extractionThe mixture was extracted with EtOAc
9. dry with materialThe organic layer was dried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated in vacuo
12. customThe crude product was purified by silica gel column chromatography