The methylene group of various substituted 2- and 4-benzylpyridines, benzyldiazines and benzyl(iso)quinolines was successfully oxidized to the corresponding benzylic ketones using a copper or iron catalyst and molecular oxygen as the stoichiometric oxidant. Application of the protocol in API synthesis is exemplified by the alternative synthesis of a precursor to the antimalarial drug Mefloquine. The oxidation method can also be used to prepare metabolites of APIs which is illustrated for the natural product papaverine. ICP–MS analysis of the purified reaction products revealed that the base metal impurity was well below the regulatory limit.
各种取代的2-和4-苄基吡啶、苄基二嗪和苄基(异)喹啉的亚甲基基团成功地被氧化为相应的苄基酮,使用铜或铁催化剂和分子氧作为化学计量氧化剂。该方案在API合成中的应用以替代合成抗疟药物美氟喹的前体为例。这种氧化方法还可用于制备API的代谢产物,以天然产物樟碱为例进行说明。对纯化的反应产物进行ICP-MS分析显示,基础金属杂质远低于监管限值。