The synthesis and properties of tricyclic pimaranes containing a C-16 β-carboline are reported. A Pictet–Spengler reaction of methyl 15-oxo-16-formylisopimarate (prepared in situ from the 15-oxo-15,16-dihydroisopimarate) and tryptamine or tryptophan methyl ester in the presence of trifluoroacetic acid formed a mixture of terpenoid 1,2,3,4-tetrahydro-β-carbolines, 3,4-dihydro-β-carbolines, and β-carbolines. Tetrahydro- and dihydro-β-carbolines in CHCl3 were oxidized to the corresponding β-carbolines by treatment in air with basic Al2O3.

中文翻译：

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高级萜类化合物的合成转化。38.* 合成含有 β-咔啉和三环二萜的偶联物

报道了含有 C-16 β-咔啉的三环 pimaranes 的合成和性质。在三氟乙酸的存在下，15-氧-16-甲酰基异海松酸甲酯（由 15-氧-15,16-二氢异海马酸原位制备）和色胺或色氨酸甲酯的 Pictet-Spengler 反应形成萜类化合物 1,2 的混合物,3,4-四氢-β-咔啉、3,4-二氢-β-咔啉和β-咔啉。通过在空气中用碱性 Al2O3 处理，CHCl3 中的四氢和二氢 β-咔啉被氧化成相应的 β-咔啉。