抗癌药β-榄香烯分子内部运动的13C核自旋弛豫研究

首次应用变温实验方法和¹³C核自旋弛豫方法研究了抗癌药β-榄香烯小分子的内部运动状况。结果表明β-榄香烯分子的六元环在所研究的温度范围(298~318K)内几乎是刚性的。该分子的整体滚动自扩散活化能为14kJ/mol.其六元环外侧链基团CH₂=CCH₃-和CH₂=CH-的整体内旋转扩散活化能均为19kJ/mol.而与该六元环直接相连的甲基的内旋转扩散活化能为18kJ/mol.这个数值大大高于连在六元环上不同位置的两个侧链基团CH₂=CCH₃一中甲基的内旋转扩散活化能(其数值分别为了7kJ/mol和2.8KJ/mol).3个不同位置的甲基的内旋转扩散活化能有很大差别可能是由它们所处的分子空间环境不同而引起的。

THE INVESTIGATION OF MOLECULAR INTERNAL MOTIONS OF ANTICANCER DRUG β-ELEMENE BY 13C NMR RELAXATION

The internal motions of β-Elemene, which is anti-cancer compound, have been investigated by using variable temperature ¹³C NMR relaxation experiments for the rirst time.The results show that the hexacyclic ring in β-Elemene is almost rigid in experimental temperature range from 298K to 318K and the self-diffusion activation energy of overall motion of the molecule is 14 kJ/mol. All the intenal rotation activation energies for side Chain molccular groups CH₂=CCH₃-and CH₂=CH-connecting with the hexacyclic ring are 19 kJ/mol.The methyl group linking directly the hcxacyclic ring has much higher internal rotation activation energy,which is 18 kJ/mol, than those in two side chain groups CH₂=CCH₃-which connect with the hexacyclic ring at different positions and moreover, the methyl groups in the two side chain groups CH₂=CCH₃-have different internal rotation activation energies which are 7,7 kJ/mol and 2.8 kJ/mol, respectively; This may result from that the three methyl groups have different space circumstances in β-Elemene.