Boron tribromide → Apigenin dimethylether

HRID 1976350Notes

Reaction equation

HRID 1976350 reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[O:19][C:18]3[C:13](=[C:14]([O:22]C)[CH:15]=[C:16]([O:20][CH3:21])[CH:17]=3)[C:11](=[O:12])[CH:10]=2)=[CH:5][CH:4]=1.B(Br)(Br)Br>C(Cl)Cl>[CH3:21][O:20][C:16]1[CH:17]=[C:18]2[C:13]([C:11](=[O:12])[CH:10]=[C:9]([C:6]3[CH:5]=[CH:4][C:3]([O:2][CH3:1])=[CH:8][CH:7]=3)[O:19]2)=[C:14]([OH:22])[CH:15]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 797305,7,4'-Trimethylapigenin

Product 1

HCID 5281601Apigenin dimethyletherYield 85.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 5b (10.0 g, 32.1 mmol) in 200 mL anhydrous CH2Cl2 was added dropwise a 1 M solution of BBr3 (35.3 mL, 35.3 mmol) over 15 min at room temperature with magnetic stirring. A thick yellow precipitate formed rapidly during the addition. After stirring 5 h, the reaction was quenched by adding 200 mL EtOH, and the solvent was then evaporated in vacuo. The yellow residue was triturated with 300 mL boiling 50% EtOH. After cooling to room temperature, the yellow solid was collected on a Büchner funnel, rinsed with 500 mL 50% EtOH and air dried. Recrystallization from 1.5 L EtOH provided 8.16 g (85.4%) of the title product as fine, pale-yellow needles; mp 176-177° C. (lit.25 mp 174-175° C.); 1H NMR (CDCl3) δ 3.88 (s, 3 H), 3.89 (s, 3 H), 6.36 (d, 1 H, J=2.1 Hz), 6.48 (d, 1 H, J=2.1 Hz), 6.57 (s, 1 H), 7.01 (d, 2 H, JAB=9.0 Hz), 7.84 (d, 2 H, JAB=9.0 Hz), 12.81 (s, 1 H); EI-MS m/z 298 (M+, 100). Anal. calcd for C17H14O5: C, 68.45; H, 4.73. Found: C, 68.25; H, 4.77.

Workup

  1. customA thick yellow precipitate formed rapidly during the addition
  2. customthe reaction was quenched
  3. additionby adding 200 mL EtOH
  4. customthe solvent was then evaporated in vacuo
  5. customThe yellow residue was triturated with 300 mL
  6. customthe yellow solid was collected on a Büchner funnel
  7. washrinsed with 500 mL 50% EtOH and air
  8. customdried
  9. customRecrystallization from 1.5 L EtOH

Sources & evidence

ORD record
ord-ccce8da5303640e98c8456c02ef36288
Source dataset
uspto-grants-2001_05
Patent number
US06225481B1

Reaction notes

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