Sodium hydride → tert-Butyl 3-(tert-butoxycarbonylphenylmethyl)-5-cyano-2-oxo-2,3-dihydro-benzimidazole-1-carboxylate

Participants

Reaction Steps

To a chilled solution of 5-cyano-2-oxo-2,3-dihydro-benzoimidazole-1-carboxylic acid tert-butyl ester (808 mg, 3.1 mmol) in dry DMF (15 mL) was added NaH (60% dispersion mineral oil, 131 mg, 3.3 mmol) under N2 atmosphere. The reaction was stirred at room temperature for 15 min. Then at 0° C., a solution of bromo-phenylacetic acid tert-butyl ester (887 mg, 3.3 mmol) in DMF (5 mL) was added. The reaction was stirred at room temperature for 2 hours, diluted with ethyl acetate, washed with water, with a saturated NH4Cl aqueous solution, brine, dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by flash chromatography in silica gel using 15% ethyl acetate in n-heptane as eluent to afford 3-(tert-butoxycarbonyl-phenyl methyl)-5-cyano-2-oxo-2,3-dihydro-benzoimidazole-1-carboxylic acid tert-butyl ester (VIIc) (1.1 g, 78%) as a white solid.

Provenance & Evidence