两个三萜(14S,17S,20S,24R)-25-羟基-14,17-环-20,24-环氧-malabarican-3-酮(CEM,1a)和(14S,17S,20S,24R)-20,24,25-三羟基-14,17-环马沙拉巴蛋白聚糖-3-酮(CM,2a)与环丁烷环进行了报道,具有与ocotillone(1b)和gardubryoneC(2b)相同的NMR数据,分别。可能会报告不正确的结构。因此,通过CASE算法和DFT化学位移预测实现了这些三萜的结构再分析,结果表明,CEM和CM的结构可能不正确。为了进一步验证化合物1的结构,HMBC,采用1H-1HCOSY和HSQC-TOCSY光谱。在这里,我们修改了CEM和CM的结构,我们的研究还表明,CASE算法和DFT化学位移预测可以支持有效的结构重新分配方法。
Two triterpenes (14S,17S,20S,24R)-25-hydroxy-14,17-cyclo-20,24-epoxy-malabarican-3-one (CEM, 1a) and (14S,17S,20S,24R)-20,24,25-trihydroxy-14,17-cyclomalabarican-3-one (CM, 2a) with a cyclobutane ring were reported, which have the same NMR data as ocotillone (1b) and gardaubryone C (2b), respectively. An incorrect structure might be reported. Therefore, the structure reanalysis of these triterpenes was achieved by
CASE algorithm and DFT chemical shift predictions, and the results showed that the structures of CEM and CM might be incorrect. To further verify the structure of compound 1, the HMBC, 1H-1H COSY and HSQC-TOCSY spectra were employed. Herein, we revised the structure of CEM and CM, and our study also showed that
CASE algorithm and DFT chemical shift predictions can hold the post of effective structure reassignment method.