The synthesis and characterization of different N-phenyl-N-(1-phenylhex-5-en-1-yl)acetamides is presented. Two conformational isomers were observed for one of the compounds in their1H/13C-NMR spectra. Computational calculations and dihedral angle comparison using the allylic system coupling constants (J) were carried out to determine the isomeric structures responsible for signals duplicity and chemical shifting