Reactivity of<i>C</i>-Amino-1,2,4-triazoles toward Electrophiles: A Combined Computational and Experimental Study of Alkylation by Halogen Alkanes
作者:Victor M. Chernyshev、Anna G. Vlasova、Alexander V. Astakhov、Svitlana V. Shishkina、Oleg V. Shishkin
DOI:10.1021/jo502405q
日期:2015.1.2
3-amino- than for the 5-amino-1H-1,2,4-triazoles. Increasing electrophile hardness should increase the probability of attack at the N-4 atom of the triazole ring, whereas increasing softness should enhance the probability of attack at the N-2 atom and 3-NH2 group. Calculated transition state energies of model SN2 reactions and experimental studies showed that quaternization of 1-substituted 3-amino- and
计算和实验方法的组合用于检查C-氨基-1 H -1,2,4-三唑与亲电试剂反应的结构-反应关系。预测3-氨基-和3,5-二氨基-1 H -1,2,4-三唑的整体亲核性高于5-氨基-1 H -1,2,4-三唑的整体亲核性。Fukui函数和分子静电势表明,与5-氨基-1 H -1,2,4-三唑相比,3-氨基-涉及氨基的反应更容易发生。亲电子硬度的增加应增加在三唑环的N-4原子处发生进攻的可能性,而柔软性的增加应在N-2原子和3-NH处发生进攻的可能性2组。计算的模型S N 2反应的过渡态能和实验研究表明,许多烷基卤化物对1-取代的3-氨基-和3,5-二氨基-1 H -1,2,4-三唑进行季铵化反应的选择性低,且可以涉及N-2和N-4原子以及3-NH 2基团作为反应中心。一种基于容易获得的1-取代的3-乙酰氨基-1,2,4-季铵化的选择性合成1,4-二取代的3-氨基-和3,5-二氨基-1,2,4