Boron tribromide → HCID 15064033, compound

Participants

Reaction Steps

A solution of boron tribromide (20 g. 80 mmol) in methylene chloride (20 mL) is added dropwise to a vigorously stirred solution of 4,4-bis(3,4-dimethoxyphenyl)butyrolactone (10.0 g. 27.9 mmol) in methylene chloride (200 mL) at -78° C. Stirring is continued for 3 hours at 78° C., and then at room temperature overnight. Ice (100 g) is added to the mixture, and organic layer is separated. The aqueous layer is extracted with ethyl acetate (3×100 mL). The combined organic solutions are dried over sodium sulfate, and concentrated in vacuo. The residue is chromatographed over a silica gel colum using a mixture of chloroform and ethanol (98:2 v/v) as the eluent to give 1-(3,4-di-hydroxyphenyl)-4,6,7-trihydroxynaphthalene (4.5 g. 53%), mp 224°-226° C. 1H NMR (Me2SO-d6) δ9.6-8.8 (5H, m, OH, exchangeable), 7.4-6.5 (7H, m, aromatic H).

Provenance & Evidence