Reactions of carbonyl compounds in basic solutions. Part 15. The alkaline hydrolysis of N-methyl, N-phenyl and bicyclo lactams, penicillins and N-alkyl-N-methylacetamides
作者:Keith Bowden、Keith Bromley
DOI:10.1039/p29900002111
日期:——
suggest the detailed mechanisms. All the β-lactams appear to react with rate-determining addition of hydroxide anion; while the N-alkyl γ- and δ-lactams and N-alkyl-N-methylacetamides have rate-determining ring fission of the tetrahedral adduct, assisted by water-catalysis. The reactivity of penicillin in alkaline hydrolysis has been analysed by the studies of model compounds. These show that the increased
已经在几个温度下测量了在水中或在二甲基亚砜水溶液中一系列N-甲基,N-苯基和双环内酰胺,青霉素和N-烷基-N-甲基乙酰胺的碱水解速率系数。在底物和碱中反应都是一级反应。反应性与底物的结构有关,特别是N-取代,环大小和稠环效应。反应性以及活化参数,动力学溶剂和溶剂同位素效应均被用来表明详细的机理。所有的β-内酰胺似乎都与决定加入氢氧根阴离子的反应。而N-烷基γ-和δ-内酰胺和N-烷基-N-甲基乙酰胺具有速率决定四面体加合物的环裂变,并借助水催化。青霉素在碱性水解中的反应性已通过模型化合物的研究进行了分析。这些表明,青霉素β-内酰胺环的增加的反应性是由稠合的环结构和酰氨基侧链的直接作用引起的。