Advanced In-Line Purification Technologies in Multistep Continuous Flow Pharmaceutical Synthesis

Continuous flow synthesis is a widely used method for synthesizing fine chemicals due to its benefits such as process intensification, improved reproducibility, and the ability to perform otherwise impossible transformations. Multistep continuous flow synthesis (MCFS) simplifies the synthesis of complex molecules by telescoping multiple steps into a streamlined and potentially automated process, reducing human efforts and time. Despite these advantages, challenges such as solid formation, solvent and reagent incompatibilities, and intermediate purification difficulties limit the development of MCFS. Overcoming these challenges will accelerate the innovative development of MCFS, thereby leading to enhanced multistep synthesis. This Perspective highlights representative examples of complex molecule production enabled by MCFS, where various in-line purification technologies were utilized during the flow processes.