triethylamine T=20°C; Michael reaction; 5 h;

diethyl-1,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylate; silica gel in benzene 0.5 h; Heating;

1: triethylamine / 17 h 2: pyridine / 2 h / Ambient temperature 3: sodium carbonate / benzene / 5 h / Heating 4: 86 percent / 3,5-bis(ethoxycarbonyl)-2,6-dimethyl-1,4-dihydropyridine, silica gel / benzene / 0.5 h / Heating View Scheme