Boron tribromide → HCID 20069025, compound

Temperature

-78 °C

To a solution of 6.5 g (23 mmol) of 5,6-dimethoxy-3-phenyl-1,2,3,4-tetrahydro-1-naphthalenone (prepared from 2,3-dimethoxybenzaldehyde by the procedures described in Example 1) in 80 mL of anhydrous methylene chloride at -78° C., under nitrogen atmosphere, was added dropwise 100 mL (100 mmol) of a 1 M solution of boron tribromide in methylene chloride. The reaction mixture was stirred at -78° C. for 0.5 h and then at ambient temperature for 1 h. TLC analysis of the reaction mixture on silica gel plates eluted with 20% ethyl acetate in hexane indicated that the reaction was complete. The reaction mixture was cooled to -78° C. and 500 mL of methanol was added dropwise. The mixture was allowed to warm to ambient temperature and then was stirred for 1 h at ambient temperature and concentrated under reduced pressure. The residue was dissolved in methanol and the methanol was evaporated in vacuo. The residue was then purified on a silica gel column eluted with ethyl acetate:hexane (1:5 v/v) to give 5.57 g (95% yield) of the title compound.

1. customat -78° C.
2. waitat ambient temperature for 1 h
3. washTLC analysis of the reaction mixture on silica gel plates eluted with 20% ethyl acetate in hexane
4. temperatureThe reaction mixture was cooled to -78° C.
5. addition500 mL of methanol was added dropwise
6. temperatureto warm to ambient temperature
7. stirringwas stirred for 1 h at ambient temperature
8. concentrationconcentrated under reduced pressure
9. dissolutionThe residue was dissolved in methanol
10. customthe methanol was evaporated in vacuo
11. customThe residue was then purified on a silica gel column
12. washeluted with ethyl acetate:hexane (1:5 v/v)

ORD record

ord-54b53984d0784d159a08d36a1a00c1cc

Source dataset

uspto-grants-1991_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04994486