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

HRID 1628406Notes

Reaction equation

HRID 1628406 reaction equation
[Cl:1][C:2]1[C:10]2[NH:9][C:8](=O)[N:7]([CH2:12][CH2:13][CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16])[C:6]=2[C:5]([CH:20]([CH2:23][CH3:24])[CH2:21][CH3:22])=[CH:4][CH:3]=1.P(Cl)(Cl)([Cl:27])=O>>[Cl:27][C:8]1[N:7]([CH2:12][CH2:13][CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16])[C:6]2[C:5]([CH:20]([CH2:23][CH3:24])[CH2:21][CH3:22])=[CH:4][CH:3]=[C:2]([Cl:1])[C:10]=2[N:9]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 68773903Ethyl 4-[4-chloro-7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]butanoate

Product 1

HCID 68761768Ethyl 4-[2,4-dichloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]butanoateYield 34%

Procedure

The solution of ethyl 4-[4-chloro-7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]butanoate (6.8 g, 19.32 mmol) in phosphorus oxychloride (70 mL) was stirred at 100-110° C. for 2 days. After cooled to room temperature, the excess phosphorus oxychloride was removed by distillation and the residue was poured into water. The aqueous phase was extracted with ethyl acetate (100 mL×3) and the combined extracts were washed with saturated aqueous sodium bicarbonate (100 mL×2) and water (100 mL), dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column (petroleum ether/ethyl acetate, 50/1) to afford the title compound (2.4 g, 34%) as light yellow oil.

Workup

  1. customthe excess phosphorus oxychloride was removed by distillation
  2. additionthe residue was poured into water
  3. extractionThe aqueous phase was extracted with ethyl acetate (100 mL×3)
  4. washthe combined extracts were washed with saturated aqueous sodium bicarbonate (100 mL×2) and water (100 mL)
  5. dry with materialdried over sodium sulfate
  6. concentrationconcentrated in vacuo
  7. customThe residue was purified by silica gel column (petroleum ether/ethyl acetate, 50/1)

Sources & evidence

ORD record
ord-5cd088293b294c86a87c4c36ad8bd69c
Source dataset
uspto-grants-2014_07
Patent number
US08785460B2

Reaction notes

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