PECHMANN -DUISBERG Coumarin Synthesis

The Simonis chromone synthesis is the reaction of a phenol la-c with a P-keto ester 2 using an appropriate acid promoter to generate a chromone or benzo-y-pyrone 3 (also called a benzo-l,4-pyrone). While compound 3 is actually a chromenone, for this article, whether the double bond is present or not, the system will be characterized as a chromone. The condensation is related to the Pechmann-Duisberg reaction, which yields coumarins from the condensation of a phenol with a P-keto ester and like its relative, the reaction conditions require the loss of water from the ketone moiety and alcohol from the ester moiety. 

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