THE INFLUENCE OF THE LEAVING TENDENCY OF THE PHENOXY GROUP ON THE AMMONOLYSIS AND HYDROLYSIS OF SUBSTITUTED PHENYL ACETATES
THE INFLUENCE OF THE LEAVING TENDENCY OF THE PHENOXY GROUP ON THE AMMONOLYSIS AND HYDROLYSIS OF SUBSTITUTED PHENYL ACETATES
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DOI：
10.1021/ja01497a023
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发表时间：
1960-01-01
影响因子：
15
通讯作者：
MAYAHI, MF
中科院分区：
文献类型：
--
作者：
BRUICE, TC;MAYAHI, MF
已发现水溶液中的对硝基苯基、间硝基苯基、对氯苯基、乙酸苯基和对甲苯酯的氨解受到胺的一般碱催化作用，但不受到特定的裂解物离子催化作用，消除了作为中间体的酰胺离子。一般碱催化的重要性随着酚盐离子的离开倾向的增加而降低，并且对于醋酸间硝基苯酯和对硝基苯酯来说，氨解反应在没有可测量的催化作用的情况下进行。非催化氨解反应的哈米特 p 常数是一般碱催化反应的三倍。建议最符合实验数据的机制是NHj分子充当协同酸碱催化剂，从攻击性胺中除去质子，同时质子化离去基团。
The ammonolysis of^-nitrophenyl, w-nitrophenyl,^-chlorophenyl, phenyl and£-cresyl acetates in aqueous solution has been found to be subject to general base catalysisby amine but not to specific lyate ion catalysis eliminating amide ion as an intermediate. The importance of general base catalysis decreases with the increased leaving tendency of phenoxide ion and for m- and^-nitrophenyl acetates ammonolysis proceeded without measurable catalysis. The Hammett p constant for the non-catalyzed ammonolysis reaction is three times as large as that for the general base-catalyzed reaction. It is suggested that the mechanism whichfits the experimental data best is one in which an NHj molecule acts as a concerted acid-base catalyst in removing a proton from the attacking amineand simultaneouslyprotonating the leaving group.