Acid-Catalyzed Cleavage Of 2-Pyridyl and 4-Pyridyl Derivatives Of Aminomethylphosphonic Acid. Kinetic And Chemical Arguments For A Mechanism With A-S<sub>E</sub>2 Character
作者:Bogdan Boduszek、Rafał Latajka、Wojciech Leśniak
DOI:10.1080/10426500008076325
日期:2000.2
Abstract Studies of the acid-catalyzed cleavage of 2-pyridyl and 4-pyridyl(amino)methylphosphonic acids demonstrate that protonation has a profound effect on the cleavage of C-P bonds. In H2SO4, and other strong mineral acids the cleavage of aminophosphonic acids 1 and 4 exhibits a kinetic depedence on Zucker-Hammett acidity function (h o), with rate law, v = k[phosphonate]·h o, and also fulfil the
摘要 2-吡啶基和 4-吡啶基(氨基)甲基膦酸的酸催化裂解研究表明,质子化对 CP 键的裂解具有深远的影响。在 H2SO4 和其他强无机酸中,氨基膦酸 1 和 4 的裂解表现出对 Zucker-Hammett 酸度函数 (ho) 的动力学依赖,具有速率定律,v = k[膦酸酯]·ho,并且还满足 Bunnett 方法酸度函数。测得的溶剂同位素效应 KH/KD 很小,从 1b 的 1.46 到 4b 的 1.18。同位素效应表明质子参与了裂解的速率决定步骤。所有这些证据表明 1 或 4 的裂解显示了 A-SE2 字符取代反应。