Open-air N-arylation of N–H heterocycles with arylboronic acids catalyzed by copper(II) Schiff base complexes
作者:S. M. Islam、Ram Chandra Dey、Anupam Singha Roy、Sumantra Paul、Sanchita Mondal
DOI:10.1007/s11243-014-9881-2
日期:2014.11
Two copper Schiff base complexes, in both homogeneous and heterogeneous forms, were prepared and characterized by using elemental analysis, FTIR, UV–Vis spectroscopy and scanning electron microscopy. The catalytic performances of these complexes were studied in the N-arylation of N–H heterocycles with arylboronic acids in methanol without any added base at 40 °C under open air. The effects of various parameters such as solvent and temperature on the reaction system were studied. The reaction is applicable to a wide variety of N–H heterocycles and arylboronic acids. The heterogeneous catalyst was recovered by simple filtration, and reusability experiments showed that this catalyst can be used five times without much loss in the catalytic activity.
Cephem and penem compounds having a styrylmethylene moiety at the 3-position in the cephem or penem ring to which a positively charged leaving group is bonded and wherein the leaving group contains a vicinal diol or is bonded to a unsubstituted or substituted catechol. The leaving group can be a positively charge nitrogen leaving group. Cephems include cephalosporins, cephamycins, carbacephems, and oxacephems. Penems include penems, carbapenems and oxapenems. Preferred cephems are cephalosporins. Preferred penems are carbapenems. Compounds exhibit antibiotic activity against Gram-negative bacteria and/or Gram-positive bacteria. Compounds exhibit antibiotic activity against bacteria which exhibit multi-drug resistance. Compounds of the invention exhibit antibiotic activity against bacterial strains which produce extended spectrum beta-lactamases (ESBL), which produce AmpC beta-lactamases or which produce a carbapenemase. Pharmaceutical compositions comprising one or more cephems or penems or methods of treatment of bacterial infections with such compounds and compositions.
A simple and industrially viable protocol for C–N and C–O coupling was reported here. The polymer supported heterogeneous copper catalyst was prepared from chloromethyl polystyrene using a simple procedure. O-Arylation of substitutedphenols with various arylhalides was achieved using this copper catalyst in DMSO medium. This heterogeneous copper catalyst, also efficiently works for the N-arylation
Arene Amination Instead of Fluorination: Substitution Pattern Governs the Reactivity of Dialkoxybenzenes with Selectfluor
作者:Joseph N. Capilato、Thomas Lectka
DOI:10.1021/acs.joc.1c00231
日期:2021.4.16
Arene substitution patterns are well-known to affect the regioselectivity of a given transformation but not necessarily the type of reactivity. Herein, we report that the substitution pattern of alkoxyarenes dictates whether a putative one-electron or two-electron reaction predominates in reactions with Selectfluor. A series of amination products is presented, resulting from the single-electron oxidation
provided a polymer-supported copper(II) catalyst, which was effective in cross-coupling reactions between N-containing substrates and arylboronicacids using methanol as a solvent in airunderbase-freeconditions. This catalyst was also effective in N-arylation of imidazole with aryl halides in DMSO using K2CO3 as a base under nitrogen atmosphere. The catalyst was characterized by physico-chemical
将铜固定在聚苯乙烯上提供了一种聚合物负载的铜 (II) 催化剂,该催化剂在无碱条件下使用甲醇作为空气中的溶剂在含 N 底物与芳基硼酸之间的交叉偶联反应中是有效的。该催化剂在氮气氛下使用 K2CO3 作为碱在 DMSO 中对咪唑与芳基卤化物的 N-芳基化也很有效。该催化剂通过物理化学和光谱技术表征。产物N-芳基咪唑和N-芳基苯并咪唑以良好至极好的产率分离。这种铜催化剂在空气中是稳定的,可以在活性损失最小的情况下回收。