Benzimidazole → 1-[4-(1H-Benzimidazol-1-yl)phenyl]ethan-1-one

HRID 1886165Notes

Reaction equation

Br[C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH3:9])=[CH:4][CH:3]=1.[N:11]1[C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][C:14]=2[NH:13][CH:12]=1.C(=O)([O-])[O-].[K+].[K+]>CN1CCCC1=O.[Cu]>[N:11]1([C:2]2[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH3:9])=[CH:4][CH:3]=2)[C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][C:14]=2[N:13]=[CH:12]1

Participants

Conditions

Temperature: 160 °C

Procedure

A mixture of p-bromoacetophenone (3.98 g, 20 mmol), benzimidazole (4.72 g, 40 mmol), copper bronze (1.27 g, 20 mmol), anhydrous potassium carbonate (5.52 g, 40 mmol) and cuprous bromide (290 mg, 2 mmol) in dry N-methylpyrrolidinone (60 ml) was heated under nitrogen at 160° C. for 8 hours. Most of the solvent was removed by distillation under reduced pressure and the residue was diluted with dichloromethane (500 ml) and 2N sodium hydroxide (200 ml). The organic layer was washed with water (300 ml), dried (MgSO4) and concentrated to give a dark brown oil. Purification by flash chromatography (eluting with ethyl acetate gave 4'-(1-benzimidazolyl)acetophenone, 3.085 g as a pale yellow solid, m.p. 133°-135° C.

Workup

customMost of the solvent was removed by distillation under reduced pressure
additionthe residue was diluted with dichloromethane (500 ml) and 2N sodium hydroxide (200 ml)
washThe organic layer was washed with water (300 ml)
dry with materialdried (MgSO4)
concentrationconcentrated
customto give a dark brown oil
customPurification by flash chromatography (
washeluting with ethyl acetate

Sources & evidence

ORD record: ord-6c03b44c4ec14462b94c886ede0abd50
Source dataset: uspto-grants-1992_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05149814

Reaction notes

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