Benzimidazole → 3-(1-benzimidazolyl)-4-(3-indolyl)-1H-pyrrole-2,5-dione

HRID 345665Notes

Reaction equation

[H-].[Na+].[N:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[NH:5][CH:4]=1.Br[C:13]1[C:14](=[O:28])[NH:15][C:16](=[O:27])[C:17]=1[C:18]1[C:26]2[C:21](=[CH:22][CH:23]=[CH:24][CH:25]=2)[NH:20][CH:19]=1>CN(C=O)C>[N:3]1([C:13]2[C:14](=[O:28])[NH:15][C:16](=[O:27])[C:17]=2[C:18]2[C:26]3[C:21](=[CH:22][CH:23]=[CH:24][CH:25]=3)[NH:20][CH:19]=2)[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[N:5]=[CH:4]1

Participants

Conditions

Temperature: 50 °C

Procedure

260 mg of a 60% dispersion of sodium hydride in mineral oil were added to a solution of 295 mg of benzimidazole in 10 ml of DMF and the mixture was stirred under nitrogen for 0.5 hour. 582 mg of 3-bromo-4-(3-indolyl)-1H-pyrrole-2,5-dione were added and the mixture was heated to 50° C. for 18 hours. A solution of 767 mg of benzimidazole and 260 mg of sodium hydride in 10 ml of DMF was added and the mixture was heated to 90° C. for 18 hours under nitrogen. The solvent was evaporated and the residue was partitioned between dichloromethane and 2M hydrochloric acid. The precipitate was purified on silica gel with ethyl acetate/petroleum ether. Recrystallization from ethyl acetate gave 25 mg of 3-(1-benzimidazolyl)-4-(3-indolyl)-1H-pyrrole-2,5-dione, m.p. 310°-320° C.

Workup

temperaturethe mixture was heated to 90° C. for 18 hours under nitrogen
customThe solvent was evaporated
customthe residue was partitioned between dichloromethane and 2M hydrochloric acid
customThe precipitate was purified on silica gel with ethyl acetate/petroleum ether
customRecrystallization from ethyl acetate

Sources & evidence

ORD record: ord-480423e30a614a84b306e5a3d663f330
Source dataset: uspto-grants-1991_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05057614

Reaction notes

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