Synthesis, semi-empirical and ab initio calculations of tertiary amides formed from cyclic amines and 3-[3-phenyl-1,2,4-oxadiazol-5-yl]propionoyl chloride

Abstract The synthesis of four tertiary amides 5a – d formed from 3-(phenyl-1,2,4-oxadiazol-5-yl)propionoyl chloride ( 3 ) and cyclic amines 4a – d is described. The structures of these compounds have been inferred from 1 H and 13 C NMR spectroscopy. Semi-empirical (AM1) molecular orbital calculations have been performed for these molecules to learn more about their stable molecular conformations. It was possible to carry out the ab initio (RHF/STO-3G) calculations for two conformers (Prl & Pr2) of 5a . Nuclear Overhauser Enhancement Spectroscopy (NOESY) and Exchange Spectroscopy (EXSY) experiments helped us to assign H-7 and to observe the position exchange of the methylene groups attached to amide nitrogen.