Prominent Inclusion Effect of Dimethyl-β-cyclodextrin on Photoisomerization of the Thromboxane Synthetase Inhibitor (E)-4-(1-limidazoylmethyl)cinnamic Acid
作者:Fumitoshi Hirayama、Tadanobu Utsuki、Kaneto Uekama、Masaki Yamasaki、Kazuaki Harata
DOI:10.1002/jps.2600810820
日期:1992.8
The direct photoisomerization of (E)-4-(1-imidazoylmethyl)-cinnamic acid (IMC), a thromboxane synthetase inhibitor, to its (Z)-isomer at pH 2.0 was decelerated by beta-cyclodextrin (beta-CyD) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD). The photostationary composition [(Z)-isomer:IMC ratio] was shifted in favor of IMC. These effects were much greater with DM-beta-CyD than with the
β-环糊精(beta-CyD)和庚基化合物可加速血栓烷合成酶抑制剂(E)-4-(1-咪唑基甲基)-肉桂酸(IMC)的直接光异构化为其(Z)-异构体(2,6-二-O-甲基)-β-环糊精(DM-β-CyD)。光平稳组成[(Z)-异构体:IMC比]转移到有利于IMC。与母体β-CyD相比,DM-β-CyD的这些作用要大得多。通过与β-CyDs的络合物形成,光异构化的量子产率显着降低,而客体的消光系数仅略微降低。这种情况与在极性较小的溶剂中观察到的情况形成鲜明对比,表明使用β-CyD的抑制机理与极性较小的溶剂体系不同。光谱研究(紫外线,圆二色性,和核磁共振)表明,IMC以轴向模式紧密地包含在DM-β-CyD的空腔中,并且光反应位的旋转在空间上受到阻碍。结果表明,β-CyDs对IMC的光异构化的抑制作用主要来自空间位因。