Triethylamine → 5-Cyano-2-oxo-2,3-dihydro-benzoimidazole-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a chilled solution of (2-amino-4-cyanophenyl)-carbamic acid tert-butyl ester (2.1 g, 8.8 mmol) in CH2Cl2 (50 mL) and triethylamine (1.22 mL, 8.8 mmol) was added a solution of triphosgene (0.94 g, 3.2 mmol) in CH2Cl2 (50 mL) slowly. The reaction was stirred at room temperature for 3 hours, diluted with CH2Cl2, washed with water, brine, dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by flash chromatography in silica gel using a gradient from 30% to 60% ethyl acetate in n-heptane as eluent to afford 5-cyano-2-oxo-2,3-dihydro-benzoimidazole-1-carboxylic acid tert-butyl ester (1.7 g, 75%) as a white solid.

Provenance & Evidence