Kuroyanagi Masanori, Shirota Osamu, Sekita Setsuko
Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University.
Chem Pharm Bull (Tokyo). 2014;62(7):725-8. doi: 10.1248/cpb.c14-00130.
Transannular cyclizations of germacrone-4,5-epoxide under acidic and thermal conditions have been reported in our previous study. However, this process gave the different and interesting results under basic conditions. (4S,5S)-Germacrone-4,5-epoxide (1) was treated under basic conditions to yield four products (2-5). Compound 2 was an isomer of 1--(4S,5S,9Z)-4,5-epoxygermacra-7(11),9-dien-8-one--and the remaining three compounds (3-5) were eudesmane-type derivatives. Compounds 4 and 5 are new compounds. The structures of the new compounds were determined using high resolution (HR)-MS, one dimensional (1D)-NMR, 2D-NMR and circular dichroism (CD) spectroscopic data. Products 3-5 had the same carbon skeleton as that of eudesmane-type compounds; however, these compounds showed different arrangement of isoprene units to the natural eudesmane-type sesquiterpenes.
在我们之前的研究中已报道了吉马酮-4,5-环氧化物在酸性和热条件下的跨环环化反应。然而，该过程在碱性条件下给出了不同且有趣的结果。(4S,5S)-吉马酮-4,5-环氧化物(1)在碱性条件下处理得到四种产物(2 - 5)。化合物2是1的异构体——(4S,5S,9Z)-4,5-环氧吉马-7(11),9-二烯-8-酮——其余三种化合物(3 - 5)是桉叶烷型衍生物。化合物4和5是新化合物。使用高分辨率(HR)-质谱、一维(1D)-核磁共振、二维(2D)-核磁共振和圆二色性(CD)光谱数据确定了新化合物的结构。产物3 - 5具有与桉叶烷型化合物相同的碳骨架；然而，这些化合物与天然桉叶烷型倍半萜相比，异戊二烯单元的排列不同。
