The Nicotinic Pharmacophore: Thermodynamics of the Hydrogen-Bonding Complexation of Nicotine, Nornicotine, and Models
作者:Jérôme Graton、Michel Berthelot、Jean-François Gal、Christian Laurence、Jacques Lebreton、Jean-Yves Le Questel、Pierre-Charles Maria、Richard Robins
DOI:10.1021/jo035018h
日期:2003.10.1
complexes. It is consistently found that nicotine and nornicotine have two active hydrogen-bond acceptor sites, the pyridine and pyrrolidine nitrogens, and that ca. 90% (for nicotine) and 80% (for nornicotine) of the 1:1 hydrogen-bonded complexes are formed to the pyridine nitrogen, although the pyrrolidine nitrogen is the first protonation site of nicotine and nornicotine in water. The low hydrogen-bond basicity
乙酰胆碱激动剂尼古丁和降烟碱以及模型吡啶,吡咯烷和N-甲基吡咯烷的氢键结合络合物的热力学已通过FTIR光谱法在CCl(4)中对参考氢键供体4-氟苯酚进行了测定。设计了各种方法来分别测量烟碱和降烟碱各氮的氢键受体强度。在一系列3-取代的吡啶,2-取代的吡咯烷和2-取代的N-甲基吡咯烷中,与氮上的静电势以及取代基常数的相关性;和4-氟苯酚与氟化氢氢键配合物之间的线性自由能关系。一致地发现,尼古丁和去甲烟碱具有两个活性氢键受体位点,吡啶和吡咯烷氮,并且大约。尽管吡咯烷氮是水中尼古丁和降烟碱的第一个质子化位点,但90%(尼古丁)和80%(去甲烟碱)的1:1氢键配合物形成了吡啶氮。尼古丁中吡咯烷氮的低氢键碱性主要由2-(3-吡啶基)取代基的感应吸电子和空间效应解释。将络合异构体(AH ... Nsp(2)<==> AH ... Nsp(3))的吉布斯能量分成焓和熵贡献表明,有利于吡啶氮的选择性受到驱