Benzyl Bromide → 3-Benzyl-5-bromo-4-methoxy-1-methyl-1,3-dihydro-2H-benzimidazol-2-one

HRID 1056961Notes

Reaction equation

[Br:1][C:2]1[CH:12]=[CH:11][C:5]2[N:6]([CH3:10])[C:7](=[O:9])[NH:8][C:4]=2[C:3]=1[O:13][CH3:14].C(=O)([O-])[O-].[Cs+].[Cs+].[CH2:21](Br)[C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1>CN(C)C=O.C(OCC)(=O)C.O>[CH2:21]([N:8]1[C:4]2[C:3]([O:13][CH3:14])=[C:2]([Br:1])[CH:12]=[CH:11][C:5]=2[N:6]([CH3:10])[C:7]1=[O:9])[C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1

Participants

Conditions

Temperature: 60 °C

Procedure

A solution of 5-bromo-4-methoxy-1-methyl-1,3-dihydro-2H-benzimidazol-2-one (60.0 mg, 0.233 mmol) in N,N-dimethylformamide (2.31 mL) was treated with cesium carbonate (380 mg, 1.17 mmol) and benzyl bromide (99.8 mg, 0.583 mmol) and stirred at 60° C. for 30 min. The reaction mixture was diluted with ethyl acetate and water. Layers were separated and the organic layer was washed with brine, dried with magnesium sulfate, filtered, and concentrated in vacuo to give the crude product. Purification by flash column chromatography (15% EtOAc/hexanes to 40% EtOAc/hexanes) gave the desired product (73 mg, 90%). LCMS calculated for C16H16BrN2O2 (M+H)+: m/z=347.1, 349.1. found: 347.0, 349.0.

Workup

customLayers were separated
washthe organic layer was washed with brine
dry with materialdried with magnesium sulfate
filtrationfiltered
concentrationconcentrated in vacuo
customto give the crude product
customPurification by flash column chromatography (15% EtOAc/hexanes to 40% EtOAc/hexanes)

Sources & evidence

ORD record: ord-448b217fabbd4986a11c42e11d12f736
Source dataset: uspto-grants-2016_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09399640B2

Reaction notes

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