Dichloromethane → 1,2:5,6-Bis-O-(1-methylethylidene)-alpha-D-allofuranose

Temperature

0 °C

1,2:5,6-di-O-isopropylidene-α-D-glucofuranose 260 g (1 mole) was stirred for 24 h in DMSO 2000 ml and Ac2O 500 ml (5 mole) at RT. By that time, TLC (DCM (dichloromethane)/MeOH 95:5) indicated complete reaction of the starting material. The solution was then cooled to 0° C. and sodium borohydride 16 g (0.42 mole) was added portion wise. By that time, TLC (DCM/MeOH 95:5) indicated complete formation of the target compound, approx. 1 h, water 2500 ml was added and the solution was extracted with DCM 3×1000 mL. The combined organic phases was washed with water 2×1000 ml and brine and dried with magnesium sulfate and evaporated to an oil. To the oil was added tert-butyl methylether (300 mL) and extracted with water 2×750 mL. The combined water phases were extracted with dichloroethane 2×400 mL. The combined organic phases was dried with magnesium sulfate and evaporated to an oil. Crystallisations twice from cyclohexane, 500 ml and 300 ml respectively, gave 151 g (58%) of pure 1,2:5,6-di-O-isopropylidene-α-D-allofuranose.

1. customat RT
2. customreaction of the starting material
3. additionwas added
4. extractionthe solution was extracted with DCM 3×1000 mL
5. washThe combined organic phases was washed with water 2×1000 ml and brine
6. dry with materialdried with magnesium sulfate
7. customevaporated to an oil
8. additionTo the oil was added tert-butyl methylether (300 mL)
9. extractionextracted with water 2×750 mL
10. extractionThe combined water phases were extracted with dichloroethane 2×400 mL
11. dry with materialThe combined organic phases was dried with magnesium sulfate
12. customevaporated to an oil
13. customCrystallisations twice from cyclohexane, 500 ml and 300 ml respectively

ORD record

ord-3cfcd75ebb72417984cae4b31e1024ba

Source dataset

uspto-grants-2005_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06858726B2