NMR-based investigations of acyl-functionalized piperazines concerning their conformational behavior in solution.

ABSTRACT: Selected N-benzoylated piperazine compounds were synthesized to study their conformational behavior using temperature-dependent ¹H NMR spectroscopy. All investigated piperazines occur as conformers at room temperature resulting from the restricted rotation of the partial amide double bond. In the case of selected mono-N-benzoylated and unsymmetrically N,N'-substituted derivatives, the appearance of the ¹H NMR spectrum was further shaped by the limited interconversion of the piperazine chair conformations. Therefore, two different coalescence points T _C were determined and their resulting activation energy barriers ΔG ^‡ were calculated to be between 56 and 80 kJ mol^-1. In most of the cases, T

SUBMITTER: Wodtke R 

PROVIDER: S-EPMC9091627 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature