A general and efficient approach to 2H-indazoles and 1H-pyrazoles through copper-catalyzed intramolecular N–N bond formation under mild conditions
作者:Jiantao Hu、Yongfeng Cheng、Yiqing Yang、Yu Rao
DOI:10.1039/c1cc13908h
日期:——
A new efficient copper-catalyzed intramolecular amination reaction has been developed to readily synthesise a wide variety of multi-substituted 2H-indazole and 1H-pyrazole derivatives from easily accessible starting materials under mild conditions. A highly selective ligand for estrogen receptor β was prepared in three steps by employing this method.
Highly Efficient One‐Pot Three Component Synthesis of 2
<i>H</i>
‐Indazoles by Consecutive Condensation, C–N and N–N Bond Formations Using Cu/Aminoclay/Reduced Graphene Oxide Nanohybrid
作者:Somayeh Behrouz
DOI:10.1002/jhet.2777
日期:2017.5
nanohybrid (Cu/AC/r‐GO nanohybrid) as an efficient heterogeneous catalyst affords the corresponding 2H‐indazoles in good to excellent yields. The influence of effective parameters on the efficient progress of the reaction was studied. The Cu/AC/r‐GO nanohybrid is a stable and inexpensive catalyst that could be simply prepared, recovered, and reused for several reaction runs with no significant decrease in
本文描述了在无配体条件下通过铜催化的连续缩合反应,容易获得的起始原料的C–N和N–N键形成简单,直接的一锅三组分2 H-吲唑合成方法。在该方案中,在存在铜/氨基粘土/还原氧化石墨烯纳米杂化物(Cu / AC / r-GO纳米杂化物)作为高效多相催化剂的情况下处理取代的2-溴苯甲醛,结构不同的胺和[bmim] N 3对应2 H吲唑类化合物的收率为好至极好。研究了有效参数对反应有效进行的影响。Cu / AC / r-GO纳米杂化物是一种稳定且便宜的催化剂,可以简单地制备,回收并重新用于多个反应过程,而不会显着降低其反应活性。
Gold Modified Zeolite: An Efficient Heterogeneous Catalyst for <I>N</I>-Arylation of Indazole
作者:P Emayavaramban、K Kadirvelu、N Dharmaraj
DOI:10.1166/jnn.2016.12905
日期:2016.9.1
We herein report N-arylation of indazole with aryl halides using gold modified zeolites (Au-zeolites) as an efficient catalytic system. Au-zeolites with three different gold loading were prepared by ion-exchange method and characterized by UV-visible diffuse reflectance spectroscopy (UV-DRS), transmission electron microscopy and energy-dispersive X-ray spectroscopy (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The Brunauer-Emmett-Teller (BET) and Langmuir surface areas of the prepared Au(5)-zeolite catalyst were found to be 644 and 929 m2g−1 respectively. Goldmodified zeolites performed as an efficient catalytic system for N-arylation of indazole using diverse aryl halides afforded N1 arylated products in appreciable yield under mild reaction conditions. The catalyst was reusable for at least five times with only a marginal loss of activity. This simple, effective and environmentally benign heterogeneous protocol provides a safer alternative to hazardous, corrosive and more polluting conventional catalysts.
我们在此报告使用金修饰沸石(Au-zeolites)作为高效催化体系,对吲唑与芳基卤化物进行 N-芳基化反应。我们采用离子交换法制备了三种不同金负载的金沸石,并通过紫外可见漫反射光谱(UV-DRS)、透射电子显微镜和能量色散 X 射线光谱(TEM-EDX)以及 X 射线光电子能谱(XPS)对其进行了表征。制备的金(5)沸石催化剂的布鲁纳-艾美特-泰勒(BET)和朗缪尔表面积分别为 644 和 929 m2g-1。金改性沸石是一种高效的催化体系,可在温和的反应条件下,利用各种芳基卤化物对吲唑进行 N-芳基化反应,并以可观的产率获得 N1 芳基化产物。该催化剂可重复使用至少五次,活性仅略有下降。这种简单、有效和对环境无害的异构方案为危险、腐蚀性和污染性更强的传统催化剂提供了更安全的替代品。
Generation of aryl radicals from <i>in situ</i> activated homolytic scission: driving radical reactions by ball milling
The need for an operationally straightforward application of radical chemistry has led researchers to explore practical strategies to obtain and trap radicals. Herein, we report a mechanoradical generation method by direct C–N bond breaking of aryldiazonium salts using NaCl as an activator. This method opens a new pathway to radicalreactions ranging from (hetero)arylation, cascade addition, and hydrogen
for the effective synthesis of 2H-indazole because of the exceptionally high biological activity of compounds containing a 2H-indazole core. We present the ionic liquid-supported copper-catalyzed one-pot synthesis of 2H-indazoles undermicrowaveirradiation, continuing our ongoing investigation of the potential uses of bioactive compounds produced in the lab. The use of microwave and ionic liquid-supported