engleski

Conformational behavior of Cinchona alkaloids

Cinchona alkaloids are natural products isolated from bark of the Cinchona tree. They have interesting structures which consist of bicyclic aliphatic quinuclidine ring and aromatic quinoline ring, connected through a chiral carbon atom bearing hydroxyl group. Parent alkaloids and their derivatives have a variety of applications, for example as chiral agents in different chromatography techniques and chiral catalysts in asymmetric synthesis. Because of their structure and stereochemistry, Cinchona alkaloids can have a complex conformational behavior in the solution and the thorough knowledge about the dominant conformers can be crucial for understanding reaction pathways and stereochemical outcome of the catalyzed reactions. Conformational space of a few Cinchona alkaloids has been previously investigated by some techniques in the field of NMR spectroscopy and molecular modeling . In this study, complete and detailed conformational landscape of cinchonidine and its pseudo-enantiomeric pair cinchonine has been determined both experimentally, by the low temperature 1H NMR, 2D NMR spectroscopy (HSQC, COSY, NOESY) and theoretically. Furthermore, their quaternary ammonium salts were also investigated. Tensor decomposition of the ab initio molecular dynamics trajectories was used to determine the full conformational space of the investigated compounds in vacuo and in the water box.

cinchonidine, cinchonine, 1H NMR spectroscopy

nije evidentirano