Synthesis of New 1, 4-Dihydropyridines by Addition-Rearrangement Process with Imine Derivatives and β-Ketoester as Starting Materials in Solvent-Free Conditions (SUPPORTING INFORMATION)

N-substituted 1,4-dihydropyridines bearing a carboxyl group at the 4-position were synthesized in solvent-free conditions with Cu2+ as the catalyst, imine and β-ketoester as starting materials. The possible mechanism which consists of addition-rearrangement process was proposed and examined by the reaction of isolated product of first addition to β- ketoester.