Boron tribromide → 6-Bromo-4'-hydroxyflavone
Reaction equation
B(Br)(Br)Br.[Br:5][C:6]1[CH:7]=[C:8]2[C:13](=[CH:14][CH:15]=1)[O:12][C:11]([C:16]1[CH:21]=[CH:20][C:19]([O:22]C)=[CH:18][CH:17]=1)=[CH:10][C:9]2=[O:24]>ClCCl>[Br:5][C:6]1[CH:7]=[C:8]2[C:13](=[CH:14][CH:15]=1)[O:12][C:11]([C:16]1[CH:21]=[CH:20][C:19]([OH:22])=[CH:18][CH:17]=1)=[CH:10][C:9]2=[O:24]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A dichloromethane solution (12 ml) that contained boron tribromide was slowly added to a dichloromethane solution (215 ml) that contained compound 15 (400 mg, 1.21 mmol) while stirring under cooling on ice, and the obtained mixture was then reacted. After completion of the reaction, purified water (100 ml) was added to the reaction solution, and the dichloromethane layer was extracted. The extract was dried over anhydrous sodium sulfate, and the solvent was then distilled away under reduced pressure. The residue was subjected to silica gel column chromatography using ethyl acetate/hexane (2/5) as an elution solvent, so as to obtain a product of interest, 6-bromo-4′-hydroxyflavone (compound 16). Yield: 50 mg (yield constant: 13.1%) 1H NMR (300 MHz, CDCl3) δ10.38 (s, 1H), 8.09 (s, 1H), 7.97-8.00 (m, 3H), 7.76 (d, J=9.0 Hz, 1H), 6.93-6.96 (m, 3H).