PROCESS FOR PRODUCING 3,4-DIHYDROCOUMARIN DERIVATIVES

摘要

PURPOSE:To effectively obtain the title compound for perfume by heating 3-(2- cyclohexanoyl)propionic acid esters in the presence of a hydrogenation- dehydrogenation catalyst to carry out cyclodehydrogenation reaction and then partially hydrogenating by-product directly using hydrogen. CONSTITUTION:3-(2-Cyclohexanoyl) propionic acid esters expressed by formula I (R1 to R4 are each H, methyl or ethyl; at least two among R1 to R4 are H; R5 is 1-4C alkyl) are subjected to heating and cyclodehydrogenation in the presence of at least one solid metal catalyst selected from the group consisting of platinum, palladium, iridium, rhodium and nickel at about 100-350 deg.C, preferably about 230-260 deg.C. Cumarins expressed by formula II and produced as a by-product are successively directly partially hydrogenated using hydrogen without separating the cumarins to provide the compound expressed by formula III. The above-mentioned catalyst is preferably used at an amount of about 0.5-2wt.% based on the compound expressed by formula I.