Azobisisobutyronitrile → Isopropyl [4-chloro-7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]acetate

Participants

Reaction Conditions

Reaction Steps

To a solution of isopropyl [7-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]acetate (17.9 g, 58.8 mmol) and 2,2′-azobisisobutyronitrile (966 mg, 5.88 mmol) in chlorobenzene (170 mL) was added portionwise N-chlorosuccinimide (7.85 g, 58.8 mmol) at 65° C., and the mixture was stirred at 70° C. for 3.5 days. After cooling, the reaction mixture was neutralized with saturated aqueous sodium hydrogen carbonate (200 mL), and the aqueous layer was separated and extracted with ethyl acetate (200 mL). The combined organic layer was washed with aqueous sodium chloride (200 mL) and brine (150 mL), dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 15-25% ethyl acetate/n-hexane gradient mixture to give the title compound (15.0 g, 44.3 mmol, 75.3%) as a solid.

Provenance & Evidence