Authors:René Becker, Sebastiaan (Bas) A.M.W. van den Broek, Pieter J. Nieuwland, Kaspar Koch and Floris P.J.T. Rutjes
To expand the knowledge base for fundamental organic reactions in continuous flow, the α-bromination of acetophenone was successfully transformed from a known batch procedure to a continuous flow process in 99 % yield through D-optimal optimisation and subsequent scale-up of the validated optimum. Using a preparative scale system, a space–time yield of 0.26 kg/m3/s (comparable literature batch reaction 0.24 kg/m3/s) was achieved under conditions suitable for laboratory and small-scale industrial application where high yield or purity is required, e.g., when expensive substrates are used.
Authors:Caroline Bosch, Pablo López-Lledó, Josep Bonjoch, Ben Bradshaw, Pieter J. Nieuwland, Daniel Blanco-Ania and Floris P. J. T. Rutjes
An Amberlite IR 120 H-promoted one-pot Fischer indolization from a cis-decahydroquinoline using a range of phenylhydrazines led to compounds with the pyrido[2,3-a]carbazole scaffold. The process may be conducted either in batch mode or in a continuous manner in a flow reactor. The stereochemical course of the Fischer indole reaction changed in going from using free phenylhydrazine to the corresponding hydrochloride in batch conditions, whereas, with the short reaction times in continuous flow, no changes due to isomerization processes were observed.