物理化学学报 >> 2002, Vol. 18 >> Issue (05): 420-425.doi: 10.3866/PKU.WHXB20020508

研究论文 上一篇    下一篇

紫杉醇的核磁共振谱及其分子几何构型的从头算研究

许旋;徐志广;罗一帆   

  1. 华南师范大学化学系,广州 510631;中山医科大学天然药物研究室,广州 510089
  • 收稿日期:2001-10-12 修回日期:2001-12-10 发布日期:2002-05-15
  • 通讯作者: 许旋 E-mail:xuxuan@scnu.edu.cn

Ab Inito Study on δ 1HNMR and δ 13CNMR of Taxol and It′s Molecular Geometry

Xu Xuan;Xu Zhi-Guang;Luo Yi-Fan   

  1. Department of Chemistry,South China Normal University,Guangzhou 510631;Department of Natural Drug,Sun Yatsen University of Medical Sciences,Guangzhou 510089
  • Received:2001-10-12 Revised:2001-12-10 Published:2002-05-15
  • Contact: Xu Xuan E-mail:xuxuan@scnu.edu.cn

摘要: 应用规范不变原子轨道GIAO法在HF/631G水平计算了MM3、PM3和HF/STO3G三种最优分子构型下紫杉醇的δ 1HNMR和δ 13CNMR.对NMR化学位移计算值与实验值的对比和误差的统计和分析表明,采用HF/STO3G优化的几何构型计算得到的化学位移误差最小,因此这一构型与实际分子最为接近.从理论构型得到4OAc与3′H的距离为0.266 3 nm,4OAc与3′Ph的距离为0.310 4 nm,4OAc与2OCOPh的距离为0.370 7nm,支持了Williams等关于紫杉醇分子内存在NOE (nuclear overhauser effect)效应及Velde等关于在极性溶剂中4OAc与3′Ph、2OCOPh形成分子内疏水簇的观点.

关键词: 紫杉醇, 核磁共振谱, 规范不变原子轨道法, 从头算, 几何构型优化

Abstract: The geometrical conformation of taxol has been optimized by MM3,PM3 and HF/STO3G method,respectively.An ab initio GIAO method at HF/631G level has been used to predict theoretically 1HNMR and 13CNMR chemical shifts for the conformations by three geometry optimization methods.The results show that the calculated δ 1HNMR and δ 13CNMR for the geometrical conformation optimized by HF/STO3G are the most accurate in comparison with experimentally observed data.It is inferred that,therefore,the geometrical conformation optimized by HF/STO3G must probably be approximate to the real one of taxol in d6DMSOD2O70%. From the geometrical conformation of taxol optimized by HF/STO3G,the distances between 4OAc and 3′H,4OAc and 3′Ph,4OAc and 2OCOPh are found to be 0.266 3 nm,0.310 4 nm and 0.370 7 nm,respectively.These distances are within the effective acting distances producing nuclear overhauser effect (NOE),which theoretically supports Williams′ view that there is a NOE effect in taxol molecule,and Velde′s view that there is a hydrophobic cluster formed by 4OAc,3′Ph and 2OCOPh in taxol molecule.

Key words: Taxol, NMR, GIAO(Gaugeindependant atomic orbital), Ab initio,