Flow Chemistry: Recent Developments in the Synthesis of Pharmaceuticals

Synopsis

Organic synthesis has traditionally been performed in batch that means in round-bottomed flasks, test tubes or closed vessels; however, continuous flow processes have gained lately much attention from synthetic organic chemists. Application of these systems for the preparation of fine chemicals, such as natural products or active pharmaceutical ingredients (APIs) is becoming very popular, especially in academia. Although pharma industry still relies on multipurpose batch or semi-batch reactors, it is evident that interest is arising towards continuous flow manufacturing of APIs.

Recently, the safe manufacturing of organic intermediates and APIs under continuous flow conditions has been deeply examined in different reviews, where some positive features have been highlighted; for example, some synthetic steps that were not permitted for safety reasons (e.g. use of potentially toxic or explosive intermediates, reactions run under high pressures or above the boiling point of the solvent) could be performed under flow conditions with minimum risk. For these reasons, flow chemistry can be seen as a novel technology that opens the way for new synthetic routes of valuable molecules.

Aim of the presentation will be to highlight very recent advances concerning the continuous flow multistep synthesis of organic molecules, which found application as APIs. Without claiming to be complete, a general overview of different approaches, technologies and synthetic strategies will be given, hoping to contribute to a gap-closure between academic research and pharmaceutical manufacturing.

Our purpose is to illustrate some of the potentialities of continuous flow organocatalysis and offer a starting point to develop new methodologies for the stereoselective synthesis of chiral drugs.