Rotational Behavior of N-(5-Substituted-pyrimidin-2-yl)anilines: Relayed Electronic Effect in Two N-Ar Bond Rotations.

N-Methyl-2-methoxymethylanilines 1 bearing various 5-substituted-pyrimidin-2-yl groups were prepared, and their rotational behaviors were explored in detail. It was revealed that the rotational barriers around two N-Ar bonds increase in proportion to the electron-withdrawing ability of substituents X at the 5-position.