Phosphorus oxychloride → 2-Chloro-7-(1-ethylpropyl)-1,4-dimethyl-1H-benzimidazole

HRID 1698564Notes

Reaction equation

HRID 1698564 reaction equation
[CH2:1]([CH:3]([C:6]1[C:11]2[N:12]([CH3:16])[C:13](=O)[NH:14][C:10]=2[C:9]([CH3:17])=[CH:8][CH:7]=1)[CH2:4][CH3:5])[CH3:2].P(Cl)(Cl)([Cl:20])=O>>[Cl:20][C:13]1[N:12]([CH3:16])[C:11]2[C:6]([CH:3]([CH2:4][CH3:5])[CH2:1][CH3:2])=[CH:7][CH:8]=[C:9]([CH3:17])[C:10]=2[N:14]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 672728947-(1-Ethylpropyl)-1,4-dimethyl-1,3-dihydro-2H-benzimidazol-2-one

Product 1

HCID 672727562-Chloro-7-(1-ethylpropyl)-1,4-dimethyl-1H-benzimidazoleYield 88%

Conditions

Temperature
110 °C

Procedure

A mixture of 7-(1-ethylpropyl)-1,4-dimethyl-1,3-dihydro-2H-benzimidazol-2-one (105 mg, 0.452 mmol) in phosphorous oxychloride (1.23 mL) was stirred at 110° C. for 3 h. The reaction was allowed to cool to room temperature and concentrated in vacuo. The residue was dissolved in ethyl acetate, washed with aqueous sodium bicarbonate and brine. The organic layer was dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue was purified by column chromatography on silica gel (n-hexane/ethyl acetate=10:1-1:1) and crystallized from ethyl acetate/n-hexane to afford the title compound as colorless crystals (100 mg, 88%).

Workup

  1. temperatureto cool to room temperature
  2. concentrationconcentrated in vacuo
  3. dissolutionThe residue was dissolved in ethyl acetate
  4. washwashed with aqueous sodium bicarbonate and brine
  5. dry with materialThe organic layer was dried over magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated in vacuo
  8. customThe residue was purified by column chromatography on silica gel (n-hexane/ethyl acetate=10:1-1:1)
  9. customcrystallized from ethyl acetate/n-hexane

Sources & evidence

ORD record
ord-52303e01920e4ba3b963fa8485ad02c2
Source dataset
uspto-grants-2012_04
Patent number
US08163935B2

Reaction notes

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