2,5-Hexanedione → 7-(2,5-Dimethyl-1H-pyrrol-1-yl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one

HRID 1698550Notes

Reaction equation

[NH2:1][C:2]1[C:7]2[N:8]([CH3:12])[C:9](=[O:11])[NH:10][C:6]=2[CH:5]=[CH:4][CH:3]=1.[CH3:13][C:14](=O)[CH2:15][CH2:16][C:17](=O)[CH3:18].C(=O)([O-])O.[Na+]>C(O)(=O)C>[CH3:18][C:17]1[N:1]([C:2]2[C:7]3[N:8]([CH3:12])[C:9](=[O:11])[NH:10][C:6]=3[CH:5]=[CH:4][CH:3]=2)[C:14]([CH3:13])=[CH:15][CH:16]=1

Participants

Conditions

Temperature: 90 °C

Procedure

To a suspension of 257 mg (1.57 mmol) of 7-amino-1-methyl-1,3-dihydro-2H-benzimidazol-2-one in 2 mL of acetic acid was added 0.18 mL (1.57 mmol) of 2,5-hexanedione, the mixture was stirred at 90° C. for 1 hour. After cooling, the reaction mixture was neutralized by saturated aqueous sodium hydrogen carbonate and extracted with ethyl acetate (X2). The combined organic layer was washed with brine (X1), dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 25-50% ethylacetate/n-hexane gradient mixture to give 258 mg (68%) of the title compound.

Workup

temperatureAfter cooling
extractionextracted with ethyl acetate (X2)
washThe combined organic layer was washed with brine (X1)
dry with materialdried over sodium sulfate
concentrationconcentrated in vacuo
customThe residue was purified by silica gel column chromatography
washeluting with a 25-50% ethylacetate/n-hexane gradient mixture

Sources & evidence

ORD record: ord-d60e54c0ab7f42a5b2bacd754876cdb7
Source dataset: uspto-grants-2012_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08163935B2

Reaction notes

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