| 摘要 |
PURPOSE:To obtain the title derivative useful as a raw material for anthelmintic agents in high purity with hardly any by-products, by oxidizing the hydroxyl group at the 5-position of milbemycins using gamma-type manganese dioxide as an oxidizing agent. CONSTITUTION:The hydroxyl group at the 5-position of milbemycins having a basic skeleton expressed by the formula (R is methyl, ethyl or isopropyl) is oxidized. In the process, gamma-type manganese dioxide is used as an oxidizing agent to afford the aimed compound. Furthermore, the amount of the above- mentioned manganese dioxide used is preferably 4-5 times based on the milbemycins. The reaction temperature is preferably 0-10 deg.C and a halogenated hydrocarbon, such as methylene chloride, is preferred as a reaction solvent. |
