Multicomponent synthesis of highly functionalized pyridin-2(1H)-ones

A multicomponent reaction (MCR) is a one-pot reaction of three or more starting compounds to form a single product. We used a MCR between 3-formylchromone, Meldrum’s acid and a primary amine to form a pyridone ring. A pyridone is a nitrogen heterocycle containing a carbonyl group. We scanned the optimal conditions of the reaction by varying the solvent, the temperature, the concentration and the amount of reagents. The reaction achieved high yields and two pyridone final products were obtained, one with a carboxylic acid using methanol as solvent at room temperature, and the other, without the carboxylic acid, when the reaction was carried out in refluxing water with tetrabutylammonium bromide. Using the optimal conditions for the purpose of study the reaction mechanism and more importantly the reaction range of possible products, we scoped the reaction by varying the amine and the diketone-like reagent. The results show that Meldrum’s acid is important for the reaction, but the amine can add variability to the reaction