Phosphorus tribromide → 2-Bromomethyl-5-chloro-4-methoxy-3-methyl benzofuran

HRID 29465Notes

Reaction equation

HRID 29465 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([CH2:10]O)=[C:7]([CH3:12])[C:6]=2[C:13]=1[O:14][CH3:15].P(Br)(Br)[Br:17]>ClCCl.N1C=CC=CC=1>[Br:17][CH2:10][C:8]1[O:9][C:5]2[CH:4]=[CH:3][C:2]([Cl:1])=[C:13]([O:14][CH3:15])[C:6]=2[C:7]=1[CH3:12]

Participants

5

Reactant 2

HCID 24614Phosphorus tribromide2×HCID 68717159(5-Chloro-4-methoxy-3-methyl benzofuran-2-yl)-methanol

Product 1

HCID 687124062-Bromomethyl-5-chloro-4-methoxy-3-methyl benzofuranYield 99%

Reagents, catalysts & solvents 2

HCID 1049PyridineCatalystHCID 6344DichloromethaneSolvent

Procedure

To a 0° C. solution of (5-chloro-4-methoxy-3-methyl benzofuran-2-yl)-methanol (0.29 g; 1.3 mmol) in dichloromethane (5 mL) was added neat phosphorus tribromide (0.18 mL; 0.52 g; 1.9 mmol; 1.5 eq) and pyridine (3 drops). The ice bath was removed and the reaction was allowed to warm to room temperature overnight. Additional phosphorus tribromide (0.09 mL; 0.26 g; 0.95 mmol; 0.75 eq) was added and stirring continued at room temperature. After two hours, the reaction was quenched with ice and extracted twice with ethyl acetate. The combined organic layers were washed with water and saturated sodium bicarbonate, followed by drying over magnesium sulfate, filtration and concentration in vacuo to give essentially pure 2-bromomethyl-5-chloro-4-methoxy-3-methyl benzofuran (0.37 g; 99%).

Workup

  1. customThe ice bath was removed
  2. customcontinued at room temperature
  3. customthe reaction was quenched with ice
  4. extractionextracted twice with ethyl acetate
  5. washThe combined organic layers were washed with water and saturated sodium bicarbonate
  6. dry with materialby drying over magnesium sulfate, filtration and concentration in vacuo

Sources & evidence

ORD record
ord-b697ffeb200344aeac8f59e68b515013
Source dataset
uspto-grants-2008_09
Patent number
US07420001B2

Reaction notes

Loading…