4-Substituted carbamazepine derivatives: conformational analysis and sodium channel-blocking properties

The physicochemical properties of 4-substituted carbamazepine derivatives were investigated. It was elucidated that the 4-substitution is not effective in reducing the rotations (E/Z) about the N—C1′ axes around the outer carbamoyl moiety. However, the atropisomers were isolated with high stereochemical stability, meaning that the 4-substitution reduced the butterfly motion of the tricyclic ring system efficiently. The Cl/CH3-substituted carbamazepine derivatives showed greater inhibitory effects on hNav1.2 Na channel currents compared with carbamazepine, although no difference in the activity between enantiomers was observed.