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

HRID 1460294Notes

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-bdf32a8d29f043cba20ac7f98573535f
Source dataset: uspto-grants-1991_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05070205

Reaction notes

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