Importance

Loading Importance Indicators...

Abstract

A process for producing a 3,4-dihydrocoumarin compound represented by formula (II): ##STR1## wherein R.sub.1 to R.sub.4 are as defined in the specification, comprising the steps of: (1) heating a 3-(2-cyclohexanoyl)propionic acid ester compound represented by formula (I): ##STR2## wherein R.sub.1 R.sub.5 are as defined in the specification, in the presence of at least one solid metal catalyst, thereby to allow said compound of formula (I) to undergo ring formation and dehydrogenation to yield said 3,4-dihydrocoumarin compound of formula (II) and, as a by-product, a coumarin compound represented by formula (III): ##STR3## wherein R.sub.1 to R.sub.4 are as defined above; (2) adding a catalyst which is as defined above to said reaction mixture, or bringing said reaction mixture into contact with oxygen to activate said catalyst used in said ring formation and dehydrogenation, without separating said coumarin compound from the reaction mixture that has undergone said ring formation and dehydrogenation; and (3) partially hydrogenating said by-product coumarin compound in said reaction mixture with hydrogen so as to convert said coumarin compound to a 3,4-dihydrocoumarin compound.

Loading the Abstract Image...

First Claim