Academic Department of Chemistry and Biology, Federal University of Technology - Paraná, Rua Deputado Heitor de Alencar Furtado, 5000, 81280-340 Curitiba, Brazil.
Department of Chemical Engineering, Federal University of Paraná, Av. Cel. Francisco H. dos Santos, 100, 81531-980, Curitiba, Paraná, Brazil.
J Org Chem. 2021 Mar 5;86(5):4027-4034. doi: 10.1021/acs.joc.0c02809. Epub 2021 Feb 15.
Organophosphate (OP) pesticides are responsible for numerous human deaths every year. Nucleophilic substitution is an important method to mitigate the toxicity of obsolete stocks of OPs. Herein, the degradation of ,-diethyl-2,4-dinitrophenyl phosphate (DEDNPP) and pesticide diethyl-4-nitrophenyl phosphate (Paraoxon) promoted by 1,2,4-triazole (TAZ) was investigated by means of kinetic studies, nuclear magnetic resonance (NMR) analyses, and theoretical calculations. Results showed fast degradation of OPs is promoted by the anionic form of the nucleophile (TAZ(-)) in pH > 8.5 (optimal at pH = 11). Rate enhancements of 10 and 10-fold in relation to neutral hydrolysis of DEDNPP and Paraoxon were observed, respectively, consistent with alpha-nucleophiles reactivity. TAZ(-) regioselectively promotes the degradation of DEDNPP via P-O bond break, forming a quickly hydrolyzable phosphorylated intermediate, regenerating the nucleophile. Calculations using M06-2X/6-311++G(d,p) level of theory revealed that the equivalent nitrogen atoms of TAZ(-) are the main nucleophilic center of the molecule. This study expands the knowledge on the reactivity of iminic compounds as detoxificant agents of OPs, indicating the efficiency and selectivity of TAZ(-) in aqueous medium, encouraging the design of novel TAZ-based catalysts.
有机磷（OP）农药每年导致许多人死亡。亲核取代是减轻过时 OP 库存毒性的重要方法。本文通过动力学研究、核磁共振（NMR）分析和理论计算，研究了 1,2,4-三唑（TAZ）对 - 二乙基-2,4-二硝基苯基磷酸酯（DEDNPP）和农药二乙基-4-硝基苯基磷酸酯（Paraoxon）的降解作用。结果表明，在 pH > 8.5（最佳 pH = 11）时，亲核试剂（TAZ(-)）的阴离子形式促进了 OP 的快速降解。DEDNPP 和 Paraoxon 的中性水解的速率分别增强了 10 倍和 10 倍，与α-亲核试剂的反应性一致。TAZ(-)通过 P-O 键断裂选择性地促进 DEDNPP 的降解，形成快速水解的磷酸化中间产物，再生亲核试剂。使用 M06-2X/6-311++G(d,p)理论水平的计算表明，TAZ(-)的等效氮原子是分子的主要亲核中心。本研究扩展了关于亚氨基化合物作为 OP 解毒剂的反应性的知识，表明了 TAZ(-)在水介质中的效率和选择性，鼓励设计基于 TAZ 的新型催化剂。
