Inhibitory and Cooperative Effects Regulated by pH in Host–Guest Complexation between Cationic Pillar[5]arene and Reactive 2-Carboxyphthalanilic Acid
作者:Eduardo V. Silveira、Vanessa Nascimento、Eduardo H. Wanderlind、Ricardo F. Affeldt、Gustavo A. Micke、Luis Garcia-Rio、Faruk Nome
DOI:10.1021/acs.joc.9b01377
日期:2019.8.2
study of host–guest complexation between reactive 2-carboxyphthalanilic acid (CPA) and two cationic pillararenes has been carried out. Host–guest complexation with significant kinetic effects was observed only with the smaller cavity size pillararene (P5A). Kinetics in the pH range 1.50–6.40, ESI–MS, 1H NMR titration, and ROESY experiments were performed to characterize the complexes. High binding stoichiometry
已经进行了反应性2-羧基邻苯二酸(CPA)和两个阳离子柱芳烃之间的主客体络合研究。仅在较小腔尺寸的柱状芳烃(P5A)中观察到具有显着动力学效应的主客体络合物。在1.50–6.40的pH范围内进行动力学,ESI–MS,1 H NMR滴定和ROESY实验来表征复合物。在所有CPA质子化状态下均观察到高结合化学计量比(H:G 2)。该系统是pH依赖性的,并且通过提高双阴离子CPA 2–的浓度(变构行为)而发生协同作用的反转(负向正)。对于生理pH值,缔合常数K 1:1不变(10 4 M–1),而K 1:2从10 2 M增加到10 4 M –1,并且抑制作用增加到222倍。NMR结果阐明了复合物的结构,使我们能够创建H-H相互作用的图谱,该图很好地描述了复合物中相互作用的多样性和数量。
Reactions of cyclic anhydrides XVI
作者:V. Balasubramaniyan、N.P. Argade
DOI:10.1016/0040-4020(89)80114-0
日期:1989.1
acetate-acetic anhydride underwent double cyclisation leading to pyrrolobenzoxazinones Va-g carrying an angular acetate. A one-flask reaction of dimethylmaleic anhydride and phthalicanhydride with anthranilic acid furnished the angular hydroxy benzoxazinones IVh and IVi respectively, which were converted to the corresponding acetates Vh and Vi. The acetates Va, Vc, Vf, Vg and Vi underwent solvolysis to the
Products from dehydration of dicarboxylic acids derived from anthranilic acid
作者:Per Wiklund、Ivan Romero、Jan Bergman
DOI:10.1039/b306032b
日期:——
Treatment of N-(carboxymethyl)-anthranilic acids 1 with several dehydrating agents, gave the cyclic ortho amides 6, or the 7-membered anhydrides 7. After reaction of N-(carboxymethyl)-anthranilic acid (1a) with acetic anhydride, a diacetylated fused diketopiperazine indole dimer (18) could be isolated. Dehydrations of 2,2'-iminobis-benzoic acid led to the corresponding cyclic ortho amides 23. The dynamic
Coordination among Bond Formation/Cleavage in a Bifunctional-Catalyzed Fast Amide Hydrolysis: Evidence for an Optimized Intramolecular <i>N</i>-Protonation Event
作者:Leandro Scorsin、Ricardo F. Affeldt、Bruno S. Oliveira、Eduardo V. Silveira、Matheus S. Ferraz、Fábio P. S. de Souza、Giovanni F. Caramori、Fredric M. Menger、Bruno S. Souza、Faruk Nome
DOI:10.1021/acs.joc.9b03383
日期:2020.4.3
that remains viable involves general acid proton delivery to the amide nitrogen by a carboxyl, while the other carboxylate engages in nucleophilic attack upon the amide carbonyl; a substantially unchanged amide carbonyl in the transition state; two concurrent bond-forming events; and a spatiotemporal-base rate acceleration. This mechanism is supported by molecular dynamic simulations which confirm a persistent