Phosphorus oxychloride → 2-Chloro-7-(2,5-dimethyl-1H-pyrrol-1-yl)-1-methyl-1H-benzimidazole
Reaction equation
[CH3:1][C:2]1[N:3]([C:8]2[C:13]3[N:14]([CH3:18])[C:15](=O)[NH:16][C:12]=3[CH:11]=[CH:10][CH:9]=2)[C:4]([CH3:7])=[CH:5][CH:6]=1.P(Cl)(Cl)([Cl:21])=O>>[Cl:21][C:15]1[N:14]([CH3:18])[C:13]2[C:8]([N:3]3[C:2]([CH3:1])=[CH:6][CH:5]=[C:4]3[CH3:7])=[CH:9][CH:10]=[CH:11][C:12]=2[N:16]=1Participants
3
Conditions
- Temperature
- 85 °C
Procedure
A mixture of 239 mg (0.991 mmol) of 7-(2,5-dimethyl-1H-pyrrol-1-yl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one in 2 mL of phosphorus oxychloride was stirred at 85° C. for 4 hours. After cooling, phosphorus oxychloride was evaporated in vacuo. The residue was diluted with ice and neutralized by aqueous sodium hydroxide. The aqueous suspension was extracted with ethyl acetate (X2). The combined organic layer was washed with water (X1) and brine (X1), dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 10-20% ethylacetate/n-hexane gradient mixture to give 185 mg (72%) of the title compound.
Workup
- temperatureAfter cooling
- customphosphorus oxychloride was evaporated in vacuo
- additionThe residue was diluted with ice
- extractionThe aqueous suspension was extracted with ethyl acetate (X2)
- washThe combined organic layer was washed with water (X1) and brine (X1)
- dry with materialdried over sodium sulfate
- concentrationconcentrated in vacuo
- customThe residue was purified by silica gel column chromatography
- washeluting with a 10-20% ethylacetate/n-hexane gradient mixture
Sources & evidence
- ORD record
- ord-316de8c685814b708e15e3fab06ce74c
- Source dataset
- uspto-grants-2012_04
- Patent number
- US08163935B2
Reaction notes
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