Kinetics and Mechanism of Hydrolysis of Labile Quaternary Ammonium Derivatives of Tertiary Amines
作者:Joseph B. Bogardus、Takeru Higuchi
DOI:10.1002/jps.2600710703
日期:1982.7
The kinetics and mechanism of hydrolysis of N-(4-hydroxy-3,5-dimethylbenzyl)pyridinium bromide and similar quaternary derivatives of niacinamide, N,N-dimethylaniline, and trimethylamine were investigated. pH-Rate profiles at 25 degrees for formation of tertiary amine and 4-hydroxymethyl-2,6-dimethylphenol indicated that the zwitterionic quaternary phenoxide was the reactive species in alkaline solution
研究了N-(4-羟基-3,5-二甲基苄基)溴化吡啶和烟酰胺,N,N-二甲基苯胺和三甲胺的类似季铵衍生物的水解动力学和机理。在25度下形成叔胺和4-羟甲基-2,6-二甲基苯酚的pH值曲线表明,两性离子季酚盐是碱性溶液中的反应性物种。通过加入少量产物叔胺强烈抑制了表观水解速率,这与反应途径中存在中间体是一致的。提出了一种水解和甲醇分解这些化合物的机理,涉及可逆地形成醌甲基甲烷,4-亚甲基,-2,6-二甲基-2,5-环己二烯-1-酮,然后与溶剂或甲醇进行捕集反应。亲核试剂。用甲基或乙酰基取代酚氢极大地稳定了分子,这与所提出的机理一致。对于酯,胺的释放速率受酯基的特定碱催化水解的限制。这类化合物可用于叔胺的前药设计中。讨论了醌次甲基中间体在结构相似的药物(如肾上腺素)降解中的可能性。