反应详情

A solution of 2,3-difluoro-4-methyl phenol (3.3 g, 22.89 mmol) in THF (30 ml) was cooled to 0° C. in an ice bath, and 60% NaH (0.916 g, 22.9 mmol) was added. When the gas evolution ceased, methyl chloroformate (1.76 ml, 22.9 mmol) was added. The ice-bath was removed and the mixture was stirred at room temperature for three hours. Water was added and the mixture was extracted with EtOAc. The combined extracts were washed with water and brine, dried over MgSO4, filtered and concentrated to dryness under reduced pressure. Purification of the crude product by flash chromatography (hexanes:EtOAc 9:1) gave 3.85 g (83%) of carbonic acid 2,3-difluoro-4-methyl-phenyl ester methyl ester as a clear oil.

1. customThe ice-bath was removed
2. additionWater was added
3. extractionthe mixture was extracted with EtOAc
4. washThe combined extracts were washed with water and brine
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated to dryness under reduced pressure
8. customPurification of the crude product by flash chromatography (hexanes:EtOAc 9:1)