Alonso José L, Sanz M Eugenia, López Juan C, Cortijo Vanessa
Grupo de Espectroscopia Molecular, Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain.
J Am Chem Soc. 2009 Apr 1;131(12):4320-6. doi: 10.1021/ja807674q.
A conclusive identification of the different conformers of the neurotransmitters ephedrine, norephedrine, and pseudoephedrine has been carried out in the gas-phase by molecular beam Fourier transform microwave (MB-FTMW) spectroscopy. Three conformers of norephedrine, three conformers of ephedrine, and four conformers of pseudoephedrine have been unequivocally assigned through the analysis of their rotational spectra and the comparison of the experimental rotational and (14)N quadrupole coupling constants with those calculated ab initio. The conformational preferences have been rationalized in terms of the various intramolecular forces at play. The main stabilizing interaction is an O-H...N hydrogen bond established in the side chain of the neurotransmitters which adopt an extended disposition in their most stable form.
通过分子束傅里叶变换微波（MB-FTMW）光谱法在气相中对神经递质麻黄碱、去甲麻黄碱和伪麻黄碱的不同构象体进行了确凿的鉴定。通过对它们的转动光谱进行分析，并将实验测得的转动常数和（14）N四极耦合常数与从头算计算值进行比较，明确归属了去甲麻黄碱的三种构象体、麻黄碱的三种构象体以及伪麻黄碱的四种构象体。根据起作用的各种分子内作用力，对构象偏好进行了合理的解释。主要的稳定相互作用是在神经递质侧链中形成的O-H...N氢键，这些神经递质以最稳定的形式呈伸展排列。
