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

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Reaction Conditions

Reaction Steps

A mixture of isopropyl[4-chloro-7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]acetate (3.73 g, 11.0 mmol) and phosphorus oxychloride (20 mL) was stirred at 100° C. for 48 hours. After cooling, phosphorus oxychloride was evaporated in vacuo. The residue was neutralized with saturated aqueous sodium hydrogen carbonate and extracted with ethyl acetate (X2). The combined organic layer was washed with brine (X1), dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 5-15% ethyl acetate/hexane gradient mixture to give 3.82 g (10.7 mmol, 97.2%) of the title compound as an oil.

Provenance & Evidence