Boron tribromide → Scutellarein

HRID 1095270Notes

Reaction equation

HRID 1095270 reaction equation
B(Br)(Br)Br.C[O:6][C:7]1[CH:29]=[CH:28][C:10]([C:11]2[O:12][C:13]3[C:18]([C:19](=[O:21])[CH:20]=2)=[C:17]([O:22]C)[C:16]([O:24]C)=[C:15]([O:26]C)[CH:14]=3)=[CH:9][CH:8]=1>ClCCl>[OH:6][C:7]1[CH:29]=[CH:28][C:10]([C:11]2[O:12][C:13]3[C:18]([C:19](=[O:21])[CH:20]=2)=[C:17]([OH:22])[C:16]([OH:24])=[C:15]([OH:26])[CH:14]=3)=[CH:9][CH:8]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 961185,6,7,4'-Tetramethoxyflavone

Product 1

HCID 5281697ScutellareinYield 88%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Boron tribromide (0.7 mL) was added dropwise to a solution of the flavone 1c (68.4 mg, 0.2 mmol) in dichloromethane (3 mL) at 0° C. The mixture was allowed to warm to room temperature after 30 min and stirred at room temperature for 20 h. Then the mixture was poured into ice water (20 mL). The organic layer was separated and concentrated under reduce pressure. The aqueous layer was poured onto the organic residue. After stirring, the precipitate was filtered off and washed with water. Recrystallization from ethanol afforded the title compound (50 mg, 88%) as yellow crystals: 1H NMR (DMSO, 200 M Hz) δ 10.20 (br s, 2H), 7.90 (d, J=8.7 Hz, 2H), 6.90 (d, J=8.7 Hz, 2H), 6.72 (s 1H), 6.57 (s 1H), 3.75 (br s, 2H)); 13C NMR (DMSO, 50 M Hz) δ 182.1 (s), 163.6 (s), 161.0 (s), 153.3 (s), 149.7 (s), 147.1 (s), 129.2 (s), 128.4 (d, 2C), 121.5 (s), 116.0 (d, 2C), 104.1 (s), 102.3 (d), 93.9 (d).

Workup

  1. customThe organic layer was separated
  2. concentrationconcentrated
  3. additionThe aqueous layer was poured onto the organic residue
  4. stirringAfter stirring
  5. filtrationthe precipitate was filtered off
  6. washwashed with water
  7. customRecrystallization from ethanol

Sources & evidence

ORD record
ord-c0d0e846fd484e8f8adb5c635fbc8958
Source dataset
uspto-grants-2012_03
Patent number
US08138165B2

Reaction notes

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