| 摘要 |
PURPOSE:To enable obtaining of the subject compound which is a synthetic intermediate for coumarin in high yield for a short time by reacting a lower alkyl ester of (2-cyclohexanoyl)propionic acid in the presence of a specific catalyst and alumina under specified conditions. CONSTITUTION:A lower alkyl ester of 3-(2-cyclohexanoyl)propionic acid (CP) is heated in the presence of a Pd catalyst supported on alumina or a carrier other than the alumina and the alumina at 230-260 deg.C for a short time to provide dihydrocoumarin. The heating time is 2-5hr, preferably 2-3hr. The preferred amount of the catalyst used for the reaction is 0.05-1mol%, etc., based on methyl ether of the CP which is a raw material in the case of, e.g. the alumina supporting 3% Pd. |
