1,3-Dipolar cycloaddition of azomethine ylides derived from imines and difluorocarbene to alkynes: a new active Pb-mediated approach to 2-fluoropyrrole derivatives
作者:Mikhail S. Novikov、Alexander F. Khlebnikov、Elena S. Sidorina、Rafael R. Kostikov
DOI:10.1039/a905518e
日期:——
Domino reactions of imines with difluorocarbene in the presence of electron-deficient alkynes lead to 2-fluoropyrrole derivatives. The process involves intermediate azomethine ylide formation, its 1,3-dipolar cycloaddition to alkyne, followed by dehydrofluorination. A modified difluorocarbene generation method using active lead for dibromodifluoromethane reduction is proposed, providing shorter reaction
The cyclometallation of anthracen-9-ylmethylene-phenyl-amine with palladium(II) acetate and with the system PdCl2, NaCl and NaOAc . 3H(2)O is studied. In both cases, the Cl-H bond activation of the anthracen-9-yl group takes place, affording an entry to a new type of endocyclic six-membered cyclopalladated organic imine that contains a metallated aromatic carbon atom. (C) 2000 Elsevier Science S.A. All rights reserved.
Scandium(III) Catalysis of Transimination Reactions. Independent and Constitutionally Coupled Reversible Processes
self-sufficient transimination reaction between various types of C=N bonds in organic solvents, with turnover frequencies up to 3600 h(-)(1) and rate accelerations up to 6 x 10(5). The mechanism of the crossover reaction in mixtures of amines and imines is studied, comparing parallel individual reactions with coupled equilibria. The intrinsic kinetic parameters for isolated reactions cannot simply be added
Sc(OTf)(3) 有效地催化有机溶剂中各种类型的 C=N 键之间的自给转移反应,转换频率高达 3600 h(-)(1),速率加速高达 6 x 10(5 )。研究了胺和亚胺混合物中交叉反应的机理,比较了平行的单独反应与耦合平衡。当几种组分混合时,孤立反应的内在动力学参数不能简单地相加,并且系统的行为与构成竞争反应网络核心的独特介质的存在一致。在混合系统中,每个胺或亚胺根据它们对催化剂金属离子中心的结合亲和力竞争同一个中心枢纽。更普遍,
Synthesis of Some New Mono- and Bis-Polycyclic Aromatic Spiro and Bis-Nonspiro-β-Lactams
作者:Aliasghar Jarrahpour、Edris Ebrahimi
DOI:10.3390/molecules15010515
日期:——
Some new mono-and bis-polycyclic aromatic spiro-beta-lactams and bis-non spiro-polycyclic aromatic beta-lactams have been synthesized from imines derived from anthracene-9-carbaldehyde, 2-naphtaldehyde and a ketene derived from 9H-xanthene-9-carboxylic acid and phenoxyacetic acid by a [2+2] cycloaddition reaction. The cycloadducts were characterized by spectral data, including 1H-NMR, 13C-NMR, IR and
一些新的单和双多环芳族螺-β-内酰胺和双-非螺-多环芳族β-内酰胺已由蒽-9-甲醛、2-萘醛和9H-呫吨衍生的乙烯酮合成。 9-羧酸和苯氧乙酸通过[2+2]环加成反应。环加合物通过光谱数据表征,包括 1H-NMR、13C-NMR、IR 和元素分析。这些单螺-β-内酰胺中的一些的构型是通过 X 射线晶体分析建立的。