基于密度泛函方法的梓醇红外光谱的预测

梓醇是一种具有特殊药理活性的环烯醚萜苷类化合物.采用密度泛函(DFT)B3LYP/6-311G**方法对梓醇分子的几何构型进行全优化,得到其儿何构型参数,进一步计算得到梓醇的红外振动光谱,振动频率校正因子为0.96.对计算得到的振动频率进行归属和解析并与实验测定得纠的梓醇IR光谱特征峰比较,发现理论计算出的IR光谱与实验测定IR特征峰位具有很好的一致性,说明所采用的DFT方法能够用于梓醇分子几何构型的优化,预测难以得到标准对照品的环烯醚萜苷类化合物的IR光谱数据.     

New Glycosidic Constituents of Abutilon pakistanicum

Pakisides A and B ( 1 and 2 , resp.), new catalpol‐type iridoid glycosides, and a new glycoside, 3 , of scutellarein have been isolated from the AcOEt‐soluble fraction of the whole plant of Abutilon pakistanicum, along with buddlejoside and lapachol. The structures of new compounds were elucidated by spectroscopic techniques including ¹H‐and ¹³C‐NMR (DEPT), and 2D‐NMR experiments.