Conformational analysis of E/Z-isomeric pairs of rosuvastatin and its lactonized analogues

Most of the super-statins contain a Cdouble bond; length as m-dashC double bond spacer between the heterocyclic and the chiral dihydroxycarboxylic moieties. The known drugs are E-geometric isomers, whereas very little is known about their Z-isomeric analogues. This study explains the unusual resonance line broadening observed in 1H NMR spectra of Z-isomeric rosuvastatin analogues at room temperature, which originates from dynamic exchange between different conformers. Conformational equilibria and intrinsic preferences of Z-isomeric rosuvastatin analogues provide valuable insight into conformational variability that is important for studying potential interactions within the binding site of the enzyme.