已经详细研究了钯催化的2-溴醛和2-溴苯乙酮的芳基azo的环化反应,生成1-芳基-1 H-吲唑。使用Cd 2 CO 3或Pd(dba)2和螯合膦,其中最有效的是rac -BINAP,DPEphos和dppf,可以高收率地完成2-溴苯甲醛芳基的环化反应。以K 3 PO 4为基。通常用于分子间胺化的富电子的大体积配体,例如P tBu 3和o -PhC 6 H 4 P t已表明,Bu 2对环化无效,并且导致大量的低聚和焦油化。所开发的方法可用于制备各种带有给电子或吸电子取代基的吲唑,其中包括未保护的羧基以及各种吲唑杂类似物。反应性较低的卤化物(例如2-氯苯甲醛),2-溴苯乙酮和溴四氢萘酮的芳基hydr已实现环化。起始的纯度已被证明是一个关键参数,因为各种杂质都会抑制环化反应。
DAST-promoted Beckmann rearrangement/intramolecular cyclization of acyclic ketoximes: access to 2-oxazolines, benzimidazoles and benzoxazoles
作者:Huiqin Li、Jian Qin、Zonglian Yang、Xiaoxue Guan、Lin Zhang、Peiqiu Liao、Xingqi Li
DOI:10.1039/c5cc02155c
日期:——
The first example of DAST-promoted Beckmann rearrangement/intramolecular cyclization of acyclic ketoximes is described, which affords 2-oxazolines, benzimidazoles and benzoxazoles.
Assembly of <i>N</i>,<i>N</i>-Disubstituted Hydrazines and 1-Aryl-1<i>H</i>-indazoles via Copper-Catalyzed Coupling Reactions
作者:Xiaodong Xiong、Yongwen Jiang、Dawei Ma
DOI:10.1021/ol300847v
日期:2012.5.18
CuI-catalyzed coupling of N-acyl-N′-substituted hydrazines with aryl iodides takes place at 60–90 °C to afford N-acyl-N′,N′-disubstituted hydrazines regioselectively and thereby gives a facile method for assembling N,N-diaryl hydrazines. N-Acyl-N′-substituted hydrazines can also react with 2-bromoarylcarbonylic compounds at 60–125 °C under the catalysis of CuI/4-hydroxy-l-proline to provide 1-aryl-1H-indazoles
An efficient route to substituted 1-aryl-1H-indazoles has been developed and optimized. The method involved the preparation of arylhydrazones from acetophenone or benzaldehyde substituted by fluorine at C2 and nitro at C5, followed by deprotonation and nucleophilic aromatic substitution (SNAr) ring closure in 45-90%. Modification of this procedure to a one-pot domino process was successful in the acetophenone
A method is provided for synthesizing 1H-indazole compounds in which aromatic carbonyl compounds are reacted with a nitrogen source to form oximes which are then converted to 1H-indazoles.
提供了一种合成1H-吲唑化合物的方法,其中芳香酮化合物与氮源反应形成肟类,然后转化为1H-吲唑。
Exploring Synthetic Strategies for 1<i>H</i>‐Indazoles and Their <i>N</i>‐Oxides: Electrochemical Synthesis of 1<i>H</i>‐Indazole <i>N</i>‐Oxides and Their Divergent C−H Functionalizations
作者:Sagar Arepally、Taehoon Kim、Gyeongho Kim、Haesik Yang、Jin Kyoon Park
DOI:10.1002/anie.202303460
日期:2023.6.26
The study reports selective electrochemical synthesis of 1H-indazoles and N-oxides, where electrochemical outcomes were dictated by the cathode material (RVC=reticulated vitreous carbon). The adaptability of 1H-indazole N-oxides for various C−H functionalization reactions was showcased. Furthermore, 1H-indazole N-oxides were utilized to synthesize the pharmaceutical molecules lificiguat and YD (3)
该研究报告了 1 H-吲唑和N-氧化物的选择性电化学合成,其中电化学结果由阴极材料决定(RVC=网状玻璃碳)。展示了1 H -吲唑N -氧化物对各种 C−H 官能化反应的适应性。此外,1 H -吲唑N -氧化物被用于合成药物分子 lificiguat 和 YD (3),各种药物的关键中间体,以及有机发光二极管的前体。