# CONFORMATIONS OF p-METHOXYPHENETHYLAMINE, A NEUROTRANSMITTER

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 Title: CONFORMATIONS OF p-METHOXYPHENETHYLAMINE, A NEUROTRANSMITTER Creators: Atticks, Karissa G.; Bohn, Robert K.; Kawashima, Y.; Suenram, R. D. Issue Date: 2001 Publisher: Ohio State University Abstract: p-Methoxyphenethylamine $(CH_{3}OC_{6}H_{4}C_{a}H_{2}C_{b}H_{2}NH_{2})$ is a neurotransmitter. Seven conformers have been identified by electronic $spectroscopy^{a}$ and their conformational identities characterized by analogy to simpler related compounds, empirical force field and quantum chemical calculations, and vibrational spectra. With the $C_{a}-C_{b}$ bond lying in a plane nominally orthogonal to the benzene ring, there are nine possible conformers. With $C(phenyl)-C_{a}-C_{b}-N$ gauche, the $NH_{2}$ group has 3 possible orientations. These are doubled by the two possible planar orientations of the methoxy group. With C(phenyl)-$C_{a}-C_{b}-N$ anti, the $NH_{2}$ group again has 3 distinguishable orientations. A pair of the C(phenyl)-$C_{a}-C_{b}-N$ gauche conformers with the N lone pair directed toward the benzene ring were deemed to be missing in the electronic spectroscopic studies. The rotational spectrum was investigated at a rotational temperature near 1 K in a pulsed-jet Fourier transform microwave spectrometer. Rotational spectra of four conformers have been assigned with preliminary rotational constant values of 2832.545, 538.362, and 509.172 MHz; 2740.111, 542.176, and 507.522 MHz; 2789.609, 535.220, and 509.950 MHz; and 2750.592, 548.056, and 507.537 MHz. They all correspond to conformers with a C(phenyl)-$C_{a}-C_{b}-N$ gauche conformation coupled with the methoxy group anti'' or syn'' to the gauche $NH_{2}$ group. Structural characterization is continuing. More lines remain to be assigned. Description: $^{a}$S. J. Martinez III, et al., J. Molec. Spectrosc., 158, 82(1993) and I. Unamuno, et al., J. Phys. Chem. A, 104, 4364(2000). Author Institution: University of Connecticut; Department of Chemistry, University of Connecticut; Department of Chemistry, National Institute of Standards and Technology; Optical Technology Division, National Institute of Standards and Technology URI: http://hdl.handle.net/1811/20098 Other Identifiers: 2001-RB-05