Feeney J, Pascual C
J Pharm Pharmacol. 1984 Mar;36(3):187-9. doi: 10.1111/j.2042-7158.1984.tb06936.x.
The hindered rotation about the exocyclic amide bond of pirenzepine has been studied using 1H nuclear magnetic resonance spectroscopy. The ratios of the two slowly interconverting conformations (1:1.76 at 2 degrees C and 1:2.37 at 30 degrees C) and the rate of interconversion (1 +/- 0.5 s-1 at 20 degrees C and 247 +/- 20 s-1 at 80 degrees C with delta g ++80 = 71 KJ mol-1) have been measured at various temperatures. The observed rapid rates of interconversion allow us to eliminate the rate of conformational selection of forms II and III as a major contributor to the slow phase of the binding kinetics observed when pirenzepine binds to muscarinic receptors from rat brain (Stockton, Birdsall, Hulme and Burgen, unpublished results).
已使用氢核磁共振光谱法研究了哌仑西平环外酰胺键的受阻旋转。在不同温度下测量了两种缓慢相互转化构象的比例（2℃时为1:1.76，30℃时为1:2.37）以及相互转化速率（20℃时为1±0.5 s⁻¹，80℃时为247±20 s⁻¹，ΔG⁺⁺80 = 71 KJ mol⁻¹）。观察到的快速相互转化速率使我们能够排除形式II和III的构象选择速率，因为它是哌仑西平与大鼠脑毒蕈碱受体结合时观察到的结合动力学慢相的主要贡献因素（斯托克顿、伯德索尔、休姆和伯根，未发表结果）。
