Process for producing coumarin and derivatives thereof.

摘要

Coumarin and a derivative (2): <CHEM> (R1 to R4 = H, Me or Et, at least two of R1 to R4 being H), are produced by heating a 3-(2-cyclohexanoyl)propionic acid ester (1): <CHEM> (R5 = C1-4 alkyl) with a palladium catalyst to cause cyclization and dehydrogenation reactions. After about 80% conversion of the ester (1) the reaction temperature is increased, typically by 20 - 40 DEG C.