Continuous flow synthesis of some 6- and 1,6-substituted 3-cyano-4-methyl-2-pyridones

In this study, six 6- and 1,6-substituted-3-cyano-4-methyl-2-pyridones were synthesized in a continuous flow microreactor system. The syntheses were realized at room temperature and the obtained results were compared to those achieved within classical syntheses. In order to optimize the continuous flow syntheses and increase the yield of the products, the retention time in the microreactor was varied by changing the flow rates of the reactant solutions. Furthermore, the reaction was optimized for 3-cyano-4,6-dimethyl-2-pyridone and 3-cyano-6-hydroxy-4-methyl-2-pyridone, which are comercially important in the pharmaceutical and dye industries. Both 2-pyridones were obtained in satisfactory yield of circa 60 % in less than 10 min. The resulting compounds were characterized by their melting points, FT-IR, H-1-NMR and UV-Vis spectra. The efficiency of the presented method for the synthesis of 2-pyridone-based molecules has promising potential for industrial production.