We report here the synthesis of various alkylpyridinium and 1-alkyl-3-methylimidazolium halides on a large scale under microwave irradiation, in a closed vessel. The reaction time was drastically reduced as compared to conventional methods, and good yields were obtained.

We report here the scaling up of clinically important dihydropyridine by using a continuous microwave reactor (CMR). We also report the use of aqueous hydrotrope solution as a cheap, safe and “green” alternative to organic solvent to carry out homogeneous reactions under microwave heating. We have studied different aqueous hydrotrope solutions for the reaction in batch as well as continuous-flow process.