Solvent effects in the structure dereplication of caffeoyl quinic acids

Abstract

The choice of solvent is an important but often neglected cofactor in the structure determination and compound dereplication of caffeoyl quinic acid derivatives (CQAD). Both unforeseeable shift effects and substantial influences on molecular conformation caused by the various solvents lead to marked changes in the shifts and the coupling pattern. Therefore, the assignment of the relative stereochemistry of the cyclohexane ring substituents is complicated and can be misleading, especially when relying on literature data. Both 1H and 13C shift values were determined for prominent CQAD. Furthermore, the proton spin systems were fully analyzed in order to establish changes in molecular geometry that are due to solvent effects. Copyright © 1999 John Wiley & Sons, Ltd.