The accelerated preparation of 1,4-dihydropyridines using microflow reactors

The synthesis of 1,4-dihydropyridines was performed in a continuous-flow microreactor. Elevated temperatures accelerated the reaction rate significantly allowing the reaction to be finished in minutes (6–11 min). Different 1,4-dihydropyridines were prepared in good to excellent isolated yields (45–88% yield). The method was amenable to the preparation of daropidine, a calcium channel blocker which is currently in clinical phase 3 trials.