Sodium hydride → Ethyl 4-[3-(2-tert-butoxy-2-oxoethyl)-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl]benzoate

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Reaction Steps

To a stirred solution of ethyl 4-(2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)benzoate from Step C (590 mg, 2.09 mmol) in DMF (10 mL) at 0° C. was added sodium hydride (104 mg of a 60% dispersion in mineral oil, 2.60 mmol). The mixture was stirred for 5 min, then tert-butyl bromoacetate (489 mg, 2.51 mmol) was added and stirring was continued for 3 h. The reaction mixture was partitioned between EtOAc (200 mL) and H2O (100 mL). The organic layer was washed with H2O (50 mL), then brine (50 mL), then dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel chromatography, eluting with a gradient of hexane:EtOAc—100:0 to 0:100, to give the title compound. MS: m/z=397 (M+1).

Provenance & Evidence