Phosphorus oxychloride → Ethyl [2,4-dichloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]acetate

HRID 1398745Notes

Reaction equation

HRID 1398745 reaction equation
[Cl:1][C:2]1[C:10]2[NH:9][C:8](=O)[N:7]([CH2:12][C:13]([O:15][CH2:16][CH3:17])=[O:14])[C:6]=2[C:5]([CH:18]([CH2:21][CH3:22])[CH2:19][CH3:20])=[CH:4][CH:3]=1.P(Cl)(Cl)([Cl:25])=O>>[Cl:25][C:8]1[N:7]([CH2:12][C:13]([O:15][CH2:16][CH3:17])=[O:14])[C:6]2[C:5]([CH:18]([CH2:21][CH3:22])[CH2:19][CH3:20])=[CH:4][CH:3]=[C:2]([Cl:1])[C:10]=2[N:9]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 86632859Ethyl [4-chloro-7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]acetate

Product 1

HCID 86632860Ethyl [2,4-dichloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]acetateYield 92%

Conditions

Temperature
90 °C

Procedure

A mixture of ethyl [4-chloro-7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]acetate (2.57 g, 7.91 mmol) and phosphorus oxychloride (15 mL) was stirred at 90° C. for 3 days. After cooling, phosphorus oxychloride was evaporated in vacuo. The residue was poured into ice-cold 2N aqueous sodium hydroxide and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 10-20% ethyl acetate/n-hexane gradient mixture to give the title compound (2.49 g, 7.25 mmol, 92%) as an oil.

Workup

  1. temperatureAfter cooling
  2. customphosphorus oxychloride was evaporated in vacuo
  3. additionThe residue was poured into ice-cold 2N aqueous sodium hydroxide
  4. extractionextracted with ethyl acetate
  5. washThe organic layer was washed with brine
  6. dry with materialdried over anhydrous sodium sulfate
  7. concentrationconcentrated in vacuo
  8. customThe residue was purified by silica gel column chromatography
  9. washeluting with a 10-20% ethyl acetate/n-hexane gradient mixture

Sources & evidence

ORD record
ord-377ed045cca14d4a8d6dba2d64c3e5ef
Source dataset
uspto-grants-2014_12
Patent number
US08901141B2

Reaction notes

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