21829-09-4

555-16-8

105-45-3

21829-09-4

The general procedure for the synthesis of dimethyl 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate from p-nitrobenzaldehyde and methyl acetoacetate was as follows: ammonium acetate (1 mmol) was added to a mixture of p-nitrobenzaldehyde (1 eq.) and methyl acetoacetate (1.1 eq.) in ethanol (1.5 mL) along with Er- MOF catalyst (20 mg). The reaction mixture was stirred at 70 °C for 4 hours. Upon completion of the reaction, the catalyst was removed by centrifugal separation. Subsequently, brine (5 mL) and ethyl acetate (5 mL) were added to the reaction mixture. The mixture was extracted with ethyl acetate and the organic phases were combined and washed sequentially with saturated aqueous NaHCO3 (10 mL) and brine (10 mL). The organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure. After complete evaporation of the solvent under vacuum, the crude product was purified by column chromatography to afford the target compound dimethyl 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate. The experimental results showed that the Er-MOF catalyst could be recovered and reused five times without any significant decrease in the catalytic activity.