Structural studies of five novel bile acid-4-aminopyridine conjugates.
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.
Department of Chemistry, Laboratory of Organic Chemistry, P.O. Box 35, FIN-40014 University of Jyväskylä, Finland. kari.v.ahonen@jyu.fi
Kari V
KV
Ahonen
Manu K
MK
Lahtinen
Miika S
MS
Löfman
Anniina M
AM
Kiesilä
Arto M
AM
Valkonen
Elina I
EI
Sievänen
Nonappa
Erkki T
ET
Kolehmainen
D015761:4-Aminopyridine / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D000577:Amides / Q000138:chemical synthesis*; D001647:Bile Acids and Salts / Q000737:chemistry*; D000440:Butanols; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D018360:Crystallography, X-Ray; D000431:Ethanol; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D012997:Solvents; D013059:Spectrum Analysis, Raman; D013818:Thermogravimetry
D000577:Amides; D001647:Bile Acids and Salts; D000440:Butanols; D012997:Solvents; C043958:2-butanol; D000431:Ethanol; D015761:4-Aminopyridine