A facile synthesis of sterically hindered tetrahydropyridine derivatives: The role of 2-Picolinic acid based 1D Copper (II) coordination polymer

An alternative facile multicomponent reaction for diverse tetrahydropyridines (THPs) synthesis under an environmentally benign Cu (II) coordination polymer [Cu(2-pic)2]2H2O}n] (CP1) catalytic system has been developed. The CP1 catalyst loading of 10 mol% was applied successfully in the tandem reaction of aldehydes, amines and β-ketoesters to furnish tetrahydropyridines with yields of up to 98%. The findings show that CP1 catalytic systems are highly effectual for diversified THPs synthesis. The plausible mechanism of THPs formation was strongly promoted by CP1 and H+ ion coming from acetic acid which also functions as a solvent. The protocol's key advantages are its high atom economy, reduction of waste generated by the various chemical processes, the time and labor required to perform the experiment and its applicability to a broader substrate range.