Batch and continuous flow preparation of Hantzsch 1,4-dihydropyridines under microwave heating and simultaneous real-time monitoring by Raman spectroscopy. An exploratory study.

Dialkyl 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylates have been prepared in a batch mode under conventional heating as well as under continuous flow conditions in the Miniflow 200SS, Sairem's microwave-assisted batch and continuous flow equipment. Real-time monitoring of the reactions by Raman spectroscopy enabled to compare both heating modes and to determine (optimized) reaction times.