Synthesis and spectroscopic studies of 3-carbamoylisonicotinic acid derivatives

An unusual example of the selective hydrolysis of a cyano group to the corresponding carboxyl group under mild reaction conditions in the presence of a carboxamide group is reported. The reaction resulted in the formation of a rare combination of vicinal carboxamide and carboxyl groups on a pyridone ring. The structure of the synthesized products was thoroughly studied using one- and two-dimensional NMR experiments and the reaction pathway was monitored fluorometrically.