| abstract |
A 3-(2-oxocyclohexyl)propionic acid ester of a specified formula, which has a terminal Cl-4 alkyl, is cyclized and dehydrogenated to form the corresponding coumarin or derivative thereof in the presence as catalyst of 0.1-5 wt%, by wt of the ester, of palladium supported mostly (preferably at least 90% of the Pd) in the surface portion of a carrier, which can be an element of Group IIA, IIIA or IVA or a compound thereof, e.g. carbon, used as a powder of particle size 1-50 µm. n The reaction is at 100-350°C (preferably 230-280°C), and can be in a solvent, and optionally with a co-catalyst. n The products are obtained in better yield than with prior forms of the catalyst, and are useful in the perfume industry. |