Steric effect in alkylation reactions by<i>N</i>-alkyl-<i>N</i>-nitrosoureas: a kinetic approach
作者:J. A. Manso、M. T. Pérez-Prior、M. P. García-Santos、E. Calle、J. Casado
DOI:10.1002/poc.1402
日期:2008.11
by five N-alkyl-N-nitrosoureas (methyl-, ethyl-, propyl-, butyl-, and allylnitrosourea) were investigated in 7:3 (v/v) water/dioxane medium in the 5.0–6.5 pH range. Decomposition of alkylnitrosoureas (ANU) gives rise to alkyldiazonium ions that yield NBP-R adducts directly or through carbocations in certain instances. The NBP alkylation rate constants by these species were determined. The following sequence
4-(对硝基苄基)吡啶(NBP)的烷基化反应是通过五个N-烷基-N进行的,该陷阱是具有类似于DNA碱基的亲核特性的烷基化剂-亚硝基脲(甲基,乙基,丙基,丁基和烯丙基亚硝基脲)在7:3(v / v)水/二恶烷介质中于5.0-6.5 pH范围内进行了研究。烷基亚硝基脲(ANU)的分解产生烷基重氮离子,在某些情况下可直接或通过碳阳离子产生NBP-R加合物。确定了这些物种的NBP烷基化速率常数。发现以下烷基化电位序列:甲基->乙基->烯丙基->丙基->丁基。将Ingold-Taft相关分析应用于动力学结果表明,NBP烷基化反应主要通过空间控制发生。NBP-R加合物的摩尔吸收系数的值还揭示了空间效应对烷基化加合物形成的决定性影响。动力学结果与ANU的生物学活性一致。版权所有©2008 John Wiley&Sons,Ltd.