藏药五脉绿绒蒿碱结构和性质的理论研究

五脉绿绒蒿碱是一种从藏药五脉绿绒蒿中提取并已确认结构的新的生物碱. 采用密度泛函理论(DFT)和从头算(ab initio)方法, 在HF/6-31G*和B3LYP/6-31G*水平下全优化计算了该化合物的分子几何构型和电子结构; 依据Onsager自恰反应场(SCRF)模型考察了五脉绿绒蒿碱在氯仿、丙酮、二甲亚砜及水等溶剂中的溶剂化作用; 基于气相优化结构进行了B3LYP/6-31G*振动分析与红外光谱计算, 进一步按照统计力学原理求得了298～1500 K温度范围内该化合物的热力学性质. 此外, 还讨论了五脉绿绒蒿碱的分子结构与药效的关系.

Theoretical Study on the Structures and Properties of a Tibetan Medicine Meconoquintupline

Meconoquintupline is a new alkaloid, the molecular structure of which has been determined, and may be extracted from Meconopis quintuplinervia Regel, a traditional Tibetan medicine. In this work, a full optimal calculation on the molecular geometry and electronic structure of meconoquintupline has been per- formed using ab initio and density functional theory (DFT) methods at HF/6-31G* and B3LYP/6-31G* level, respectively. The solvent effects of meconoquintupline have also been investigated based on Onsager self-consistent reaction field (SCRF) model in chloroform, acetone, DMSO and water. On the basis of the vibration analysis and statistical thermodynamic theory, the IR spectrum and thermodynamic parameters (enthalpy, entropy and heat capacity) for the titled compound from 298 to 1500 K have been obtained ac- cording to the B3LYP/6-31G* optimized geometry in gas phase. At the same time, the relationship between molecular structure and medicine efficacy for meconoquintupline has also been analyzed.