Selective Synthesis of Indazolo[2,3‐
<i>a</i>
]quinolines via Rh(III)‐Catalyzed Oxidant‐Free [4+2] or [5+1] Annulation of 2‐Aryl‐2
<i>H</i>
‐indazoles with
<i>α</i>
‐Diazo Carbonyl Compounds
作者:Shenghai Guo、Lincong Sun、Xuzhuo Li、Xinying Zhang、Xuesen Fan
DOI:10.1002/adsc.201901422
日期:2020.2.21
A selective synthesis of 5,6‐disubstituted and 5‐substituted indazolo[2,3‐a]quinolines through a Rh(III)‐catalyzed oxidant‐free annulation of 2‐aryl‐2H‐indazoles with α‐diazo carbonyl compounds is reported. With 2‐aryl‐2H‐indazoles as the substrates, α‐diazo carbonyl compounds could act as a C2 synthon to afford 5,6‐disubstituted indazolo[2,3‐a]quinolines via a Rh(III)‐catalyzed [4+2] annulation. On
通过Rh(III)催化的2-芳基-2 H-吲唑与α-重氮羰基化合物的无氧化剂环氧化反应选择性合成5,6-二取代和5-取代的吲唑并[2,3- a ]喹啉是报告。以2-芳基-2 H-吲唑为底物,α-重氮羰基化合物可作为C2合成子,通过Rh(III)催化[ 5,6-二取代的吲唑并[2,3- a ]喹啉] [4 +2]。另一方面,当使用2-芳基-3-甲酰基-2 H-吲唑类作为底物时,α-重氮羰基化合物转变为C1合成子,需要经历更复杂的[5 + 1]环化工艺来提供5位取代的吲哚并[2,3- a ]喹啉。
Ultrasound promoted mild and facile one-pot, three component synthesis of 2H-indazoles by consecutive condensation, C N and N N bond formations catalysed by copper-doped silica cuprous sulphate (CDSCS) as an efficient heterogeneous nano-catalyst
作者:Mohammad Navid Soltani Rad
DOI:10.1016/j.ultsonch.2016.07.026
日期:2017.1
An ultrasonic promoted facile and convenient one-pot three-component procedure for the synthesis of 2H-indazole derivatives using copper-doped silica cuprous sulphate (CDSCS) as a heterogeneous nano-catalyst has been described. In this approach, ultrasonic mediated reaction of different substituted 2-bromobenzaldehydes, structurally diverse primary amines, and tetrabutylammonium azide (TBAA) as an
Electrochemical Radical–Radical Cross-Coupling Approach between Sodium Sulfinates and 2<i>H</i>-Indazoles to 3-Sulfonylated 2<i>H</i>-Indazoles
作者:Wansoo Kim、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.0c02144
日期:2020.8.21
A direct cross-coupling between sodium sulfinates and 2H-indazoles has been developed under electrochemical conditions. The utilization of a graphite anode and platinum cathode in an undivided cell with a constant current of 7 mA allowed the concurrent oxidations of sulfinates and 2H-indazoles to sulfonyl radical and radical cationic 2H-indazoles, facilitating the direct radical–radical coupling strategy
CuO nanoparticle catalysed synthesis of 2H-indazoles under ligand free conditions
作者:Nilufa Khatun、Anupal Gogoi、Pallabita Basu、Prasenjit Das、Bhisma K. Patel
DOI:10.1039/c3ra45298k
日期:——
A CuO nano catalysed one-pot synthesis of 2H-indazoles has been devised from easily accessible starting materials viz. 2-bromobenzaldehydes, primary amines and sodium azide under ligand free conditions. The nano CuO catalyst played an important role during the formation of the intermolecular C–N bond followed by the intramolecular N–N bond, providing 2H-indazoles. This method has a broad substrate scope with a high tolerance of a variety of functional groups. The catalyst can be recycled up to three times, however with slight decreases in the yields each time.
Direct Acyl Radical Addition to 2<i>H</i>-Indazoles Using Ag-Catalyzed Decarboxylative Cross-Coupling of α-Keto Acids
作者:Ganganna Bogonda、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.8b00920
日期:2018.5.4
A direct acyl radical addition to 2H-indazoles has been achieved for the first time, where the less-aromatic quinonoid 2H-indazoles readily accepted radical species to the C-3 position. Motivated by the lack of direct acylation strategy for 2H-indazoles, the current method utilizes the radical acceptability of 2H-indazoles, discovering an ambient temperature reaction to provide facile access to a diverse