Eco-Friendly Methodology to Prepare N-Heterocycles Related to Dihydropyridines: Microwave-Assisted Synthesis of Alkyl 4-Arylsubstituted-6-chloro-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate and 4-Arylsubstituted-4,7-dihydrofuro[3,4-b]pyridine-2,5(1H,3H)-dione

Here we describe the efficient synthesis of alkyl 4-arylsubstituted-6-chloro-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylates and 4-arylsubstituted-4,7-dihydro-furo[3,4-b]pyridine-2,5(1H,3H)-diones via microwave-accelerated reaction of alkyl 4-arylsubstituted-2-methyl-6-oxo-1,4,5,6-tetrahydro-3-pyridinecarboxylates with the appropriate reagents. This eco-friendly approach to these valuable dihydropyridine derivatives does not involve the harsh or highly contaminating conditions common in classical heating and offers a reduction or even elimination of solvent use and recovery, simplification of the work-up procedures, facility of scale up, and low energy consumption, in addition to moderate to higher yields.