Fig. 5: Chemical reaction promoted reversible atropisomer transformation of OC-4.
From: Controlled interconversion of macrocyclic atropisomers via defined intermediates
a Schematic representation of molecular structure conversion from C4v- to C2v-OC-4 via subjecting to hydrolysis and esterification with different alkali hydroxide salts; b Expanded view of 1H NMR spectra of OC-4 recorded in TCE-d2 after esterification following treatment of CA-4 with different alkali hydroxide salts (500 MHz); c Structure of [C2v-CA-4-3H+]3-•Na+•K+•3Cl-•DMF and C4v-CA-4 shown in stick form obtained from a single crystal structural analysis of [[C2v-CA-4-3H+]3-•Na+•K+•3Cl-•DMF]•4H3O+•9.5H2O•5DMF and [C4v-CA-4•2DMF•H2O], respectively; d Isomer fraction of various OC-4 forms (red column: C2v-OC-4; purple column: C1-OC-4; green column: Cs-OC-4; orange column: C2-OC-4; blue column: C4v-OC-4) after reesterification following C4v-OC-4 hydrolysis with different alkali hydroxide salts, error bars correspond to S.D.
