X-ray structures and computational studies of several cathinones

2-(Ethylamino)-1-(4-methylphenyl)propan-1-one (shortly named 4-MEC) (1a), 1-(1,3-benzodioxol-5-yl)-2-(methylamino)propan-1-one (shortly named methylone or 3,4-methylenedioxymethcathinone) (1b), 1-(3,4-dimethylphenyl)-2-(methylamino)propan-1-one (1c), 2-methylamino-1-(4-methylphenyl)propan-1-one (shortly named mephedrone; 4-MMC or 4-methylmethcathinone) (1d) and 2-(methylamino)-1-phenylbutan-1-one (shortly named buphedrone) (1e) and their aminium salts (2a–e), are examples of cathinones which were characterized by FTIR, UV–Vis, multinuclear NMR spectroscopy. By single crystal X-ray diffraction method structures of 2a, 2b, 2c and 2d were determined. NMR solution spectra showed readily diagnostic H-1 and C-13 signals from methyl, ethyl, N-methyl or N-ethyl groups. The diastereotopic methylene protons of 1a appear as an ABX3, and 1e and 2e appear as an ABMX3 system. The geometries of the studied compounds were optimized in singlet states using the density functional theory (DFT) method with B3LYP functional. Electronic spectra were calculated by TDDFT method. In general, the predicted bond lengths and angles are in good agreement with the values based on the X-ray crystal structure data.