Kinetics, isotope effects, and mechanism of the reaction of 1,1,1-trifluoro-2,2-bis-(4-nitrophenyl)ethane with piperidine and pyrrolidine bases in dipolar aprotic solvents
作者:Arnold Jarczewski、Grzegorz Schroeder、Miros?aw Dworniczak
DOI:10.1039/p29860000055
日期:——
The kinetics of the reaction of 1,1,1-trifluoro-2,2-bis-(4-nitrophenyl)ethane with piperidine and pyrrolidine bases in a series of solvents [acetonitrile (MeCN), benzonitrile (PhCN), and dimethyl sulphoxide (Me2SO)] are reported. The reaction is complex, leading to a 1-amino-1-fluoro-2,2-bis-(4-nitrophenyl)ethene as the final product via the intermediate 1,1-difluoro-2,2-bis-(4-nitrophenyl)ethene.
1,1,1-三氟-2,2-双-(4-硝基苯基)乙烷与哌啶和吡咯烷碱在一系列溶剂[乙腈(MeCN),苯甲腈(PhCN)和二甲基亚砜中的反应动力学] (Me 2 SO)]。该反应是复杂的,经由中间体1,1-二氟-2,2-双-(4- )产生最终产物1-氨基-1-氟-2,2-双-(4-硝基苯基)乙烯。硝基苯基)乙烯。该反应仅通过伯胺和仲胺来促进。叔胺即使在回流条件下也似乎没有活性。在PhCN和MeCN中与哌啶反应的活化熵(ΔS ‡ / J mol –1 K –1)为负且很大(– 183.7和–162.3)。在我身上反应2 SO的值仅为–77.4。在30°C时,动力学同位素效应( k H / k D)介于1.0和1.6之间。讨论了获得的结果的多步机制( E 1cB) ip,该机制由预平衡和快速加-消除步骤组成。