| 摘要 |
PURPOSE:To obtain cumarins useful as an intermediate for perfumes, medicines and agrochemicals and dyes at a high reaction rate by subjecting 3,4- dihydrocumarins to dehydrogenation reaction by evaporating a reacted liquid using a specific heating calorie. CONSTITUTION:3,4-Dihydrocumarins of formula I (R1 to R4 each is H, methyl or ethyl and two or more groups thereof are H) are subjected to dehydrogenation reaction using 80-1000kcal/kg.hr heating calorie per unit reacted liquid in the presence of a metal catalyst such as a solid metal catalyst obtained by supporting palladium on an active carbon to provide the objective cumarins of formula II. |
