This is the first chemical investigation of Chiastocaulon caledonicum, an endemic liverwort from New Caledonia. We herein present the isolation of thirteen compounds including seven undescribed sesquiterpenoids, namely four barbatane- and three myltaylane-type sesquiterpenes. The structures of these compounds were elucidated based on the interpretation of their chemical and spectroscopic/spectrometric data. Chiastocaulins A and B are the first examples of dimers based on two myltaylane units. The chemotaxonomic importance and the biosynthesis of the chiastocaulin structure are discussed. Terpenoid dimers formed via a Diels-Alder cyclization are thought to be specific to the Plagiochilaceae family.

中文翻译：

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来自地草 Chiastocaulon caledonicum 的二聚体和酯化倍半萜烯

这是对来自新喀里多尼亚的地方性苔草 Chiastocaulon caledonicum 的首次化学研究。我们在此介绍了 13 种化合物的分离，包括 7 种未描述的倍半萜类化合物，即四种 barbatane 和三种 myltaylane 型倍半萜。基于对它们的化学和光谱/光谱数据的解释，阐明了这些化合物的结构。Chiastocaulins A 和 B 是基于两个 mytaylane 单元的二聚体的第一个例子。讨论了化学分类学的重要性和 chiastocaulin 结构的生物合成。通过 Diels-Alder 环化形成的萜类二聚体被认为是 Plagiochilaceae 家族特有的。