Department of Chemistry, Laboratory of Organic Chemistry, P.O. Box 35, FIN-40014 University of Jyväskylä, Finland.
Steroids. 2012 Sep;77(11):1141-51. doi: 10.1016/j.steroids.2012.06.003. Epub 2012 Jul 16.
Synthesis and solid-state structural characterization of five bile acid amides of 4-aminopyridine (4-AP) are reported. Systematic crystallization experiments revealed a number of structural modifications and/or solvate/hydrate systems for these conjugates. Particularly, cholic acid conjugate exhibited five distinct structure modifications, including one anhydrous form, mono- and dihydrates, as well as ethanol and 2-butanol solvates. The obtained crystal forms were examined extensively with various analytical methods, including solid-state NMR, Raman, and IR spectroscopies, powder and single crystal X-ray diffraction methods, thermogravimetry, and differential scanning calorimetry. After releasing their crystal solvent molecules, the resulted non-solvated structure forms showed 50-75°C higher melting points than corresponding bile acids, and thermal degradation occurred for all conjugates at about 300-330°C. Moreover, the single crystal X-ray structure of the ursodeoxycholic acid-4-aminopyridine conjugate is reported.
报告了 4-氨基吡啶（4-AP）的五种胆酸酰胺的合成和固态结构表征。系统的结晶实验揭示了这些缀合物的许多结构修饰和/或溶剂化物/水合物系统。特别是，胆酸缀合物表现出五种不同的结构修饰，包括一种无水形式、单水合物和二水合物，以及乙醇和 2-丁醇溶剂化物。通过各种分析方法，包括固态 NMR、拉曼和红外光谱、粉末和单晶 X 射线衍射方法、热重分析和差示扫描量热法，对获得的晶体形式进行了广泛的检查。在释放其晶体溶剂分子后，所得的非溶剂化结构形式的熔点比相应的胆酸高 50-75°C，所有缀合物在约 300-330°C 时发生热降解。此外，还报道了熊去氧胆酸-4-氨基吡啶缀合物的单晶 X 射线结构。
