Synthesis, structural and conformational study of some amides derived from N-methylpiperazine

Some amides (1–6) derived from N-methylpiperazine were synthesized and studied by IR, 1H and 13C NMR spectroscopy. In CDCl3 solution, at room temperature, a fast interconversion of the piperazine ring with the N–CH3 group in equatorial position can be proposed. α,β-unsaturated compounds 4 and 5 adopt in liquid state and in solution (CCl4, CCl2CCl2, CDCl3) both s-cis and s-trans conformations.