Scale-up of 3-Acetylcoumarin (13`000 x) from R&D to production without Parameter Re-optimisation

With a large number of natural products bearing 2H- 1 -benzopyran- 2 -one heterocyclic core, coumarins have been shown to possess anticoagulant, antidiabetic and antibiotic properties.
The synthesis of coumarins can be achieved using several named reactions including the Claisen re -arrangement, Perkin reaction and Pechmann reaction. Herein we examine the synthesis of 1-(2-methyl-2H-chromen-3-yl)ethanone (3-actylcoumarin) via the Knoevenagel condensation of ethyl acetoacetate and 2-hydroxybenzaldehyde in the presence of catalytic piperidine. Owing to the use of this heterocycle as a product, reagent and ligand, it was decided to develop methodology for its efficient production under continuous flow conditions.
By utilising the scalable technology platform of Labtrix® micro reactors and KiloFlow® meso reactors, we are able to demonstrate the development of synthetic methodology on the mg-scale and subsequently translate the reaction parameters to a meso-flow reactor for the large-scale material production without the need to perform any re-optimisation of the reaction conditions.