Structural Characterization of Carane Derivative Stereoisomers - Potent Local Anesthetics

The paper reports on structural investigation and phase analysis of a newly synthesized potent local anesthetic with chiral molecular structure. Absolute structure and absolute configuration on four chiral centres was determined using microcrystalline single-crystal diffraction with anomalous scattering of X-ray radiation azimuthal scan technique. Phase analysis for new compound (KP23SS) and its epimer (KP23RS) was carried out using classical and synchrotron radiation powder diffraction. Enantiopurity of the bulk material was verified for both isomers by comparison of experimental and simulated high-resolution powder diffraction diagrams. The presence of two new polymorphic phases of KP23RS was documented. Comparative conformational analysis was carried out using differential Fourier synthesis and least-squares molecule overlap technique. A model of epimeric disorder was discussed for the homochiral phase.