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

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Reaction Conditions

Reaction Steps

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.

Provenance & Evidence