Área Académica de Química, Universidad Autónoma del Estado de Hidalgo, Km 4.5 Carretera Pachuca-Tulancingo, Mineral de la Reforma, Hidalgo, 42184 Mexico.
J Nat Prod. 2011 Sep 23;74(9):1946-51. doi: 10.1021/np200445y. Epub 2011 Sep 6.
Chemical investigations of Acacia schaffneri led to the isolation of the new diterpenoid (5S,7R,8R,9R,10S)-(-)-7,8-seco-7,8-oxacassa-13,15-diene-7,17-diol (1), together with the known (5S,7R,8R,9R,10S)-(-)-7,8-seco-7,8-oxacassa-13,15-dien-7-ol-17-al (2) and (5S,7R,8R,9R,10S)-(-)-7,8-seco-7,8-oxacassa-13,15-dien-7-ol (3). Compounds 2 and 3 were analyzed by single-crystal X-ray diffraction, while the structure of 1 was determined by 1D and 2D NMR experiments and by chemical correlation with 2. Oxidation of 3 afforded conformationally restricted (5S,8R,9R,10S)-(-)-8-hydroxy-7,8-seco-cassa-13,15-dien-7-oic acid ε-lactone (4), which was studied by vibrational circular dichroism spectroscopy. Comparison of the experimental VCD spectrum of 4 with the DFT//B3PW91/DGDZVP2 calculated spectrum assigned for the first time the absolute configuration of these seco-oxacassane diterpenes.
化学研究表明，金合欢属植物沙夫纳里含有新的二萜类化合物（5S,7R,8R,9R,10S）-（-）-7,8-降-7,8-氧杂卡莎-13,15-二烯-7,17-二醇（1），以及已知的（5S,7R,8R,9R,10S）-（-）-7,8-降-7,8-氧杂卡莎-13,15-二烯-7-醇-17-醛（2）和（5S,7R,8R,9R,10S）-（-）-7,8-降-7,8-氧杂卡莎-13,15-二烯-7-醇（3）。化合物 2 和 3 通过单晶 X 射线衍射进行分析，而化合物 1 的结构则通过 1D 和 2D NMR 实验以及与化合物 2 的化学相关性来确定。3 的氧化得到了构象受限的（5S,8R,9R,10S）-（-）-8-羟基-7,8-降-卡莎-13,15-二烯-7-羧酸 ε-内酯（4），通过振动圆二色性光谱对其进行了研究。将 4 的实验 VCD 光谱与 DFT//B3PW91/DGDZVP2 计算光谱进行比较，首次为这些 7,8-降-氧杂卡莎二萜类化合物分配了绝对构型。
