Boron tribromide → 7-Bromomethyl-5-methoxy-2-(4-methoxy-phenyl)-benzofuran

HRID 1835980Notes

Reaction equation

HRID 1835980 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH2:20]O)[C:6]2[O:10][C:9]([C:11]3[CH:16]=[CH:15][C:14]([O:17][CH3:18])=[CH:13][CH:12]=3)=[CH:8][C:7]=2[CH:19]=1.B(Br)(Br)[Br:23]>ClCCl>[Br:23][CH2:20][C:5]1[C:6]2[O:10][C:9]([C:11]3[CH:16]=[CH:15][C:14]([O:17][CH3:18])=[CH:13][CH:12]=3)=[CH:8][C:7]=2[CH:19]=[C:3]([O:2][CH3:1])[CH:4]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 10192985HCID 10192985, compound

Product 1

HCID 102867967-Bromomethyl-5-methoxy-2-(4-methoxy-phenyl)-benzofuranYield 233.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
-78 °C

Procedure

Benzyl Alcohol 3 (1.02 g, 3.59 mmole) was dissolved in dichloromethane (70 mL) and cooled to −78° C. in an dry ice/acetone bath. Boron tribromide (1.0 M in dichloromethane), (3.95 mL, 3.95 mmole) was added drop wise over 15 minutes. After 30 minutes, the light orange solution was allowed to come to room temperature and reacted for an additional four hours. The solution was concentrated and added to saturated sodium bicarbonate, and extracted with ethyl acetate. Organic layers were combined and washed with water and brine, dried over magnesium sulfate. The organic phases were concentrated and the residue was loaded on to silica gel and chromatographed with silica gel (hexanes:ethyl acetate, 9:1) to afford 2.91 g (81%) of benzyl bromide 17 as a white solid: Mp=158-160° C.; 1H NMR (DMSO-d6) δ 7.88 (d, 2 H, J=8.8 Hz), 7.23 (s, 1 H), 7.11 (d, 2 H, J=2.5 Hz), 7.09 (d, 2 H, J=8.9 Hz), 6.99 (d, 1H, J=2.5 Hz), 4.96 (s, 2 H), 3.82 (s, 3 H), 3.80 (s, 3 H).

Workup

  1. customto come to room temperature
  2. customreacted for an additional four hours
  3. concentrationThe solution was concentrated
  4. additionadded to saturated sodium bicarbonate
  5. extractionextracted with ethyl acetate
  6. washwashed with water and brine
  7. dry with materialdried over magnesium sulfate
  8. concentrationThe organic phases were concentrated
  9. customchromatographed with silica gel (hexanes:ethyl acetate, 9:1)

Sources & evidence

ORD record
ord-6dd16c1c9b3e45c788ffa0e3f6731740
Source dataset
uspto-grants-2004_08
Patent number
US06774248B2

Reaction notes

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