反应详情

A solution of boron tribromide in dichloromethane (1.0 M; 197.4 ml) was added to a solution of 2,3-difluoro-6-methoxybenzaldehyde (10.4 g; prepared in a similar manner to that described above) in dichloromethane (100 ml) under nitrogen stirring below -20° C. The resulting solution was allowed to warm to ambient temperature overnight, then methanol (200 ml) followed by water (100 ml) were added, and the mixture heated at 40° C. for 2 hours. The aqueous layer was separated and extracted with dichloromethane (2×300 ml). The combined organic solutions were extracted with aqueous sodium hydroxide solution (1 M; 3×400 ml) and the combined extracts acidified with concentrated hydrochloric acid, then extracted with ethyl acetate (3×300 ml). These combined extracts were dried over magnesium sulphate and the solvent removed in vacuo to give 2,3-difluoro-6-hydroxybenzaldehyde (8.12 g) as a solid.

1. customprepared in a similar manner to that
2. custombelow -20° C
3. additionwere added
4. temperaturethe mixture heated at 40° C. for 2 hours
5. customThe aqueous layer was separated
6. extractionextracted with dichloromethane (2×300 ml)
7. extractionThe combined organic solutions were extracted with aqueous sodium hydroxide solution (1 M; 3×400 ml)
8. extractionextracted with ethyl acetate (3×300 ml)
9. dry with materialThese combined extracts were dried over magnesium sulphate
10. customthe solvent removed in vacuo