反应详情

温度

104 °C

A mixture of D-sorbitol (1) (4.0 kg), water (560 mL) and H2SO4 (50 mL) was heated to a melt (104° C.) and stirred. After 20 h, 25 mL of H2SO4 was added. After a further 22 h, 25 mL of H2SO4 was added. After a further 32 h, the mixture was cooled to ambient temperature, neutralized carefully with solid Na2CO3 and stirred for 30 min. i-PrOH (12 L) was added, followed by anhydrous Na2SO4 (4 kg). The mixture was filtered and the solid was washed with i-PrOH (6 L) and EtOH (3 L). The filtrate was treated with activated charcoal (100 g), filtered through Celite, rinsing with 1.2 L each of i-PrOH and EtOH, then concentrated. Toluene (6 L) was added to the residue, and the mixture was concentrated in vacuo with heating to effect azeotropic removal of water. EtOH (10 L) was added to the solid residue with heating to effect dissolution. The solution was concentrated and cooled to ambient temperature to give a suspension (6 L). The solid was isolated by filtration, washed with cold EtOH (4 L) and dried. Recrystallization of the crude product (1.9 kg) from hot EtOH provided 2 (1693 g) as a white solid, mp112-112.5° C., [α]23D-22.9 ° (c 0.5, H2O). The 13C NMR spectrum of this compound agreed with that reported by Duclos et al., Synthesis, page 1087 (1994).

1. waitAfter a further 22 h
2. waitAfter a further 32 h
3. temperaturethe mixture was cooled to ambient temperature
4. additionwas added
5. filtrationThe mixture was filtered
6. washthe solid was washed with i-PrOH (6 L) and EtOH (3 L)
7. additionThe filtrate was treated with activated charcoal (100 g)
8. filtrationfiltered through Celite
9. washrinsing with 1.2 L each of i-PrOH and EtOH
10. concentrationconcentrated
11. additionToluene (6 L) was added to the residue
12. concentrationthe mixture was concentrated in vacuo
13. temperaturewith heating
14. customremoval of water
15. additionEtOH (10 L) was added to the solid residue
16. temperaturewith heating
17. dissolutiondissolution
18. concentrationThe solution was concentrated
19. temperaturecooled to ambient temperature