Continuous flow synthesis of the API buclizine under photo and electrochemical conditions

Employing photocatalysis and electrosynthesis enabling technologies, we have developed a continuous flow synthesis of the active pharmaceutical ingredient (API) buclizine, an antihistaminic and antiemetic drug. This convergent synthesis combines recent advances in ruthenium-based photocatalysis and an electrochemical reduction of carbonyl compounds, offering significant advantages over the state of the art for this API, considering both academic and industrial synthetic routes. All steps were scaled up (gram scale) under continuous flow conditions, achieving a new synthetic approach in four steps and up to 49% overall yield (58% overall yield LLS). • A new convergent continuous flow synthesis of buclizine API is described. • Photocatalysis and electrosynthesis were used as enabling technologies. • All steps were scaled up (gram scale) under continuous flow conditions. • A four-step synthesis was developed in 49% overall yield (58% overall yield LLS).