[CH2:1]([O:3][C:4](=[O:16])[CH:5]([N:13]=[C:14]=[O:15])[CH2:6][C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1)[CH3:2].[NH2:17][C:18]1[CH:25]=[CH:24][C:21]([C:22]#[N:23])=[CH:20][CH:19]=1>CN(C=O)C>[CH2:1]([O:3][C:4](=[O:16])[CH:5]([NH:13][C:14]([NH:17][C:18]1[CH:25]=[CH:24][C:21]([C:22]#[N:23])=[CH:20][CH:19]=1)=[O:15])[CH2:6][C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1)[CH3:2]To a solution of 2-isocyanato-3-phenylpropionic acid ethyl ester (6 g, 27.37 mmol) in DMF (50 ml) was added a solution of 4-aminobenzonitrile (3.23 g, 27.37 mmol) in DMF (30 ml) at 3° C. during 20 min. Stirring was continued for 7 d at room temperature, and additional 2-isocyanato-3-phenylpropionic acid ethyl ester (2.86 g) was added successively. The solvent was removed and the residue dissolved in ethyl acetate (100 ml), washed with water (20 ml), saturated aqueous KHSO4/K2SO4 solution (1:1, 2×20 ml) and with saturated aqueous NaCl solution (4×90 ml). The organic phase was dried (MgSO4), filtered and evaporated to give 12.20 g of the title compound which was used without further purification. MS 338.3 (M+1)+
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