[C:1]([O:5][C:6](=[O:17])[NH:7][C:8]1[CH:13]=[CH:12][C:11]([C:14]#[N:15])=[CH:10][C:9]=1[NH2:16])([CH3:4])([CH3:3])[CH3:2].C(N(CC)CC)C.Cl[C:26](Cl)([O:28]C(=O)OC(Cl)(Cl)Cl)Cl>C(Cl)Cl>[C:1]([O:5][C:6]([N:7]1[C:8]2[CH:13]=[CH:12][C:11]([C:14]#[N:15])=[CH:10][C:9]=2[NH:16][C:26]1=[O:28])=[O:17])([CH3:4])([CH3:2])[CH3:3]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.
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