Phosphorus oxychloride → 2,4-Dichloro-7-(1-ethylpropyl)-1-methyl-1H-benzimidazole

HRID 1698557Notes

Reaction equation

HRID 1698557 reaction equation
[Cl:1][C:2]1[C:10]2[NH:9][C:8](=O)[N:7]([CH3:12])[C:6]=2[C:5]([CH:13]([CH2:16][CH3:17])[CH2:14][CH3:15])=[CH:4][CH:3]=1.P(Cl)(Cl)([Cl:20])=O>>[Cl:20][C:8]1[N:7]([CH3:12])[C:6]2[C:5]([CH:13]([CH2:16][CH3:17])[CH2:14][CH3:15])=[CH:4][CH:3]=[C:2]([Cl:1])[C:10]=2[N:9]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 672724674-Chloro-7-(1-ethylpropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one

Product 1

HCID 672730252,4-Dichloro-7-(1-ethylpropyl)-1-methyl-1H-benzimidazoleYield 82%

Conditions

Temperature
90 °C

Procedure

A mixture of 4-chloro-7-(1-ethylpropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one (1.17 g, 4.63 mmol) in phosphorous oxychloride (28 g) was stirred at 90° 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 subjected to chromatography on silica gel (n-hexane/ethyl acetate=10:1-1:1) and crystallized from ethyl acetate-hexane to afford the title compound as colorless crystals (1.03 g, 82%). mp 94-95° C.

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. customcrystallized from ethyl acetate-hexane

Sources & evidence

ORD record
ord-5bcab18d8a724af8b5894e1be5986677
Source dataset
uspto-grants-2012_04
Patent number
US08163935B2

Reaction notes

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