Synthesis of Fluorine Analogs of Vitamin E. IV. Synthesis of Bis(trifluoromethyl)tocopherols.
摘要:
我们之前合成了单(三氟甲基)生育酚,用于通过 19F-NMR 研究生育酚在脂质体中的迁移率和取向。为了更精确地研究维生素 E 在脂质体中的行为,合成了具有两个三氟甲基的生育酚,一个在异戊烯基侧链上,另一个在苯并二氢吡喃醇环上。因此,在氯化锌存在下用6-氯-3-甲基-2-己烯醇处理二甲基氢醌,得到2-(3-氯丙基)三甲基苯并二氢吡喃醇衍生物。将它们转化为鏻盐,与三氟甲基化酮缩合,然后氢化,得到侧链上有三氟甲基且苯并二氢吡喃醇部分上有氢的生育酚。将它们在苯并二氢吡喃醇部分上卤化,并用三氟甲基碘和铜粉处理,得到标题化合物。
Improved Wittig Condensation of Trifluoromethyl Ketones with Non Stabilized Phosphorus Ylides: Application to the Synthesis of Precursors of Insect Juvenile Hormone III Trifluoroanalogues
We previously synthesized mono(trifluoromethyl)tocopherols, which were used for investigation of the mobility and orientation of tocopherol in Iliposomes by 19F-NMR. For more precise investigation of the behavior of vitamin E in liposomes, tocopherols having two trifluoromethyl groups, one on the prenyl side chain and the other on the chromanol ring, were synthesized. Thusn, dimethylhydroquinones were treated with 6-chloro-3-methyl-2-hexenol in the presence of zinc chloride to give 2-(3-chloropropyl)trimethylchromanol derivatives. These were converted to phosphonium salts, which, upon condensation with trifluoromethylated ketones followed by hydrogenation, gave tocopherols with a trifluoromethyl group on the side chain and a hydrogen on the chromanol part. These were halogenated on the chromanol part and treated with trifluoromethyl iodide and copper powder to give the title compounds.
我们之前合成了单(三氟甲基)生育酚,用于通过 19F-NMR 研究生育酚在脂质体中的迁移率和取向。为了更精确地研究维生素 E 在脂质体中的行为,合成了具有两个三氟甲基的生育酚,一个在异戊烯基侧链上,另一个在苯并二氢吡喃醇环上。因此,在氯化锌存在下用6-氯-3-甲基-2-己烯醇处理二甲基氢醌,得到2-(3-氯丙基)三甲基苯并二氢吡喃醇衍生物。将它们转化为鏻盐,与三氟甲基化酮缩合,然后氢化,得到侧链上有三氟甲基且苯并二氢吡喃醇部分上有氢的生育酚。将它们在苯并二氢吡喃醇部分上卤化,并用三氟甲基碘和铜粉处理,得到标题化合物。
Improved Wittig Condensation of Trifluoromethyl Ketones with Non Stabilized Phosphorus Ylides: Application to the Synthesis of Precursors of Insect Juvenile Hormone III Trifluoroanalogues
An improved methodology for Wittig condensation of trifluoromethyl ketones with non-stabilized phosphorus ylides, which takes place under smooth and homogeneous reaction conditions, is reported. By this procedure trifluoromethyl alkenes 3a-c are obtained in almost quantitative yields and with a high stereochemical control. The use of 3b and 3c as building blocks for the preparation of the corresponding trifluoro esters 7a and 7b, which are potential insect growth regulators, is also described.