Milbemycin derivatives: Epoxidation of milbemycins.
作者:SATORU NAITO、AKIO SAITO、YOUJI FURUKAWA、TADASHI HATA、YASUO NAKADA、SHIGEKI MURAMATSU、JUNYA IDE
DOI:10.7164/antibiotics.47.812
日期:——
Epoxidation reactions (MCPBA epoxidation and Sharpless epoxidation) were examined as a means of chemically modifying milbemycins as part of our program for discovering anthelmintics. 8, 9-Epoxy-, 14, 15-epoxy-, 8, 9-14, 15-diepoxy-, and 3, 4-8, 9-14, 15-triepoxymilbemycin A4 were se-lectively obtained from milbemycin A4 and its derivatives, in which either the C-5 and C-7 hydroxyl groups or C-5 alone were protected as appropriate by a silyl ether (in the former case) or a carbonyl group. Further silylation or epoxidation on these epoxidized compounds indicated that the configuration of each epoxide moiety of the mono- and diepoxides is in accord with that of the corresponding epoxide moiety of the triepoxide. Furthermore, in order to confirm the absolute configurations of these epoxide functionalities, an X-ray analysis of a carbamate derivative from the triepoxymilbemycin was conducted.
我们研究了环氧化反应(MCPBA 环氧化反应和 Sharpless 环氧化反应),将其作为对米贝菌素进行化学修饰的一种方法,这也是我们发现抗蠕虫药物计划的一部分。8、9-环氧-、14、15-环氧-、8、9-14、15-二环氧-和 3、4-8、9-14、15-三环氧密螺旋霉素 A4 可从密螺旋霉素 A4 及其衍生物中选择性地获得,在这些衍生物中,C-5 和 C-7 羟基或仅 C-5 被硅醚(前者)或羰基保护。对这些环氧化化合物进行进一步的硅化或环氧化处理表明,单环氧化物和二环氧化物中每个环氧化物分子的构型与三环氧化物中相应环氧化物分子的构型一致。此外,为了确认这些环氧化物官能团的绝对构型,还对三环氧吡蚜酮的氨基甲酸酯衍生物进行了 X 射线分析。