RATES OF HYDROLYSIS OF CARBAMATE AND CARBONATE ESTERS IN ALKALINE SOLUTION
RATES OF HYDROLYSIS OF CARBAMATE AND CARBONATE ESTERS IN ALKALINE SOLUTION
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DOI：
10.1002/jps.2600520908
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发表时间：
1963-01-01
影响因子：
3.8
通讯作者：
HIGUCHI, T
中科院分区：
文献类型：
--
作者：
DITTERT, LW;HIGUCHI, T
研究了几种脂肪族和芳香族氨基甲酸酯和碳酸酯在不同温度下的碱性水解速率。发现对于羟基离子和酯来说，反应都是一级反应。数据似乎表明了氨基甲酸酯水解的两种机制：由中心碳原子上的羟基离子附着引发，随后形成氨基甲酸酯离子中间体，以及涉及酰胺氢的直接电离，随后形成异氰酸酯中间体。由于后一种机制对于强亲电醇的氨基甲酸酯似乎更容易进行，因此这些化合物的 N-未取代和 N-单取代氨基甲酸酯的裂解速度比相应的二取代氨基甲酸酯高几个数量级。
The rate of the alkaline hydrolysis of several aliphatic and aromatic carbamate and carbonate esters was studied at various temperatures. The reactions were found to be first order with respect to both hydroxyl ion and the ester. The data seemed to indicate two mechanisms for the hydrolysis of the carbamates: that initiated by an hydr oxylion attachment on the central carbon atom followed by a carbamate ion intermediate, and the involving direct ionization of an amide hydrogen followed by formation of an isocyanate intermediate. Since the latter mechanism appears to proceed with much greater ease for carbamates of strongly electrophilic alcohols, the N-unsubstituted and N-monosubstituted carbamates of these compounds undergo cleavage at rates several orders of magnitude greater than those of the corresponding disubstituted carbamates.