0.17 g (0.83 mmol) of 4-nitrophenyl chloroformate and then 0.14 mL (0.83 mmol) of diisopropylethylamine are added to a solution of 0.18 g (0.55 mmol) of ethyl (Z)-2-ethoxy-3-[6-(3-methylaminophenyl)pyrid-3-yl]acrylate in 5 mL of dichloromethane. The reaction mixture is stirred for 1 hour 30 minutes at room temperature. The reaction is stopped by addition of 5 mL of water and extraction with dichloromethane. The organic phases are combined and then dried over magnesium sulfate. The solvents are evaporated off. 0.32 g (100%) of ethyl (Z)-2-ethoxy-3-(6-{3-[methyl-(4-nitrophenoxycarbonyl)amino]phenyl}pyrid-3-yl)acrylate is obtained in the form of a yellow oil. The crude product obtained is used directly in the following step.
