反应详情

To a solution of 2.50 g (13.0 mmol) 2,6-diethyl-4-methoxy-benzaldehyde in 15 ml dichloromethane at −60° C. was added dropwise 26.0 ml (26.0 mmol) of a 1 M solution of boron tribromide in dichloromethane. After the addition was complete, the reaction mixture was allowed to warm to room temperature and then heated at reflux for 16 h. The reaction mixture was then cooled to room temperature and poured onto an ice-water mixture. The mixture was diluted with dichloromethane, the phases were separated, and the organic phase was dried over Na2SO4, filtered and concentrated in vacuo. The residue was resuspended in a 1:1 mixture of ethyl acetate and diethyl ether and extracted with 1 N aqueous sodium hydroxide solution. The phases were separated and the aqueous phase was acidified to pH 1 by addition of concentrated hydrochloric acid and then extracted with ethyl acetate. The phases were separated and the organic phase was washed with saturated brine, dried over Na2SO4, filtered and concentrated in vacuo to afford 1.48 g (64%) of the title compound as a brown crystalline solid. MS (ISP): 177.4 ([M−H]−).

1. additionAfter the addition
2. temperatureheated
3. temperatureat reflux for 16 h
4. temperatureThe reaction mixture was then cooled to room temperature
5. customthe phases were separated
6. dry with materialthe organic phase was dried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. additionThe residue was resuspended in a 1:1 mixture of ethyl acetate and diethyl ether
10. extractionextracted with 1 N aqueous sodium hydroxide solution
11. customThe phases were separated
12. additionthe aqueous phase was acidified to pH 1 by addition of concentrated hydrochloric acid
13. extractionextracted with ethyl acetate
14. customThe phases were separated
15. washthe organic phase was washed with saturated brine
16. dry with materialdried over Na2SO4
17. filtrationfiltered
18. concentrationconcentrated in vacuo