An efficient method for the synthesis of 1,4-dihydropyridine derivatives in a flow microwave reactor

The synthesis of symmetrical and asymmetrical 1,4-dihydropyridines in a flow microwave reactor was performed, using calcium channel blockers API Nifedipine and Nimodipine as an example. During the experiment, a method (protocol) for a three-component Hantzsch reaction for the synthesis of symmetrical 1,4-dihydropyridines and a three-stage method for the synthesis of asymmetric 1,4-dihydropyridines was developed. The use of microwave activation significantly increased the speed of the chemical process compared to convection prototypes, while using the flow reactor allows to scale up the process. The conditions found during the experiments allowed to synthesize desired substances with a yield of 75–90%.