3D Printed Reactors for Synthesis of Active Pharmaceutical Ingredients in Continuous Flow

Advances in flow chemistry to produce active pharmaceutical ingredients (APIs) require performing reactions in tailor-made equipment as complexity of the planned setups increases. To react quickly and with low costs to these demanding reactions, additive manufacturing, also known as 3D printing, is a preferred way for the production of customized reactors. This work presents three examples of 3D printed reactors and their application for the synthesis of API precursors in continuous flow. The first case deals with an aerobic oxidation of Grignard reagents to the corresponding phenols by molecular oxygen. Here, a design concept was utilized; various stainless steel reactors were tested, and their performances were evaluated in continuous flow. Next, another stainless steel reactor was applied for achieving fast mixing in a cascade, leading to a valsartan precursor. The third and final case employed a continuous stirred tank reactor (CSTR) made of a UV-curable resin. It was used for the first step of a multiphase enzymatic decarboxylation followed by a Heck cross-coupling reaction, leading to resveratrol derivatives.