This review focuses on the flow-oriented design (FOD) in the multi-step continuous-flow synthesis of active pharmaceutical ingredients.

The first integrated continuous-flow synthesis of the drug substance flibanserin was developed, using an uninterrupted four-step sequence,viaan unprecedented route.

In microwave-assisted organic synthesis, the question of microwave effects is still debated. Proper examination of these hypothesized phenomena is encumbered by some specific features of microwave heating. We devise a convenient method to eliminate most of the irreproducibility observed in microwave-heated organic transformations by thermal conditioning of the microwave reactor cavity. To show the utility of this approach, we investigated a reaction of 2-chloropyridine, in which microwave conditions were shown to be beneficial by previous studies. Using our method to ensure proper reproducibility together with fibre optic temperature measurement, the observed differences were traced back to large hidden thermal differences, while non-thermal effects could not be detected in the comparison experiments.