Reaction #302855

Reaction equation

boron tribromide

compound 15

6-bromo-4′-methoxyflavone

→

compound 16

6-bromo-4′-hydroxyflavone

Solvents

dichloromethane

dichloromethane

Conditions

Workup

1. 1
   Temperatureunder cooling on ice
2. 2
   Otherthe obtained mixture was then reacted
3. 3
   OtherAfter completion of the reaction
4. 4
   Otherpurified water (100 ml)
5. 5
   workup.ADDITIONwas added to the reaction solution
6. 6
   Extractionthe dichloromethane layer was extracted
7. 7
   DryingThe extract was dried over anhydrous sodium sulfate
8. 8
   workup.DISTILLATIONthe solvent was then distilled away under reduced pressure

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).

Source