A New Generation of “Cholaphanes”: Steroid-Derived Macrocyclic Hosts with Enhanced Solubility and Controlled Flexibility
作者:Khadga M. Bhattarai、Anthony P. Davis、Justin J. Perry、Christopher J. Walter、Stephan Menzer、David J. Williams
DOI:10.1021/jo971272w
日期:1997.11.1
such as carbohydrates in nonpolar media. New features are the externally directed alkyl chains, promoting solubility in organic solvents, and (in the case of 3b/c) reduced conformational freedom resulting from truncation of the steroidal side-chain. In particular, modeling shows that the smallest macrocycle 3c possesses very little flexibility, preferring an open conformation which is also revealed in
大环“胆甾烷” 3a-c由廉价的类固醇胆酸合成。像早期的亲戚一样,它们的特征是带有向内羟基的大量空腔,适用于在非极性介质中结合极性分子,例如碳水化合物。新功能是外部定向的烷基链,提高了在有机溶剂中的溶解度,并且(在3b / c的情况下)由于类固醇侧链的截断而降低了构象自由度。特别地,建模显示最小的大环3c具有非常小的柔性,优选开放构象,其也在其五水合物的X射线晶体结构中揭示。NMR研究表明,所有三个胆cho与CDCl(3)中的辛基β-D-葡萄糖苷形成1:1配合物,K(a)= 600-1560 M(-)(1)。胆甾烷3b / c被证明能够从水溶液中提取甲基β-D-葡萄糖苷到CHCl(3)中。对于3c,也证明了甲基β-D-葡萄糖苷通过氯仿屏障的转运。