Iron promoted C3–H nitration of 2H-indazole: direct access to 3-nitro-2H-indazoles

2018 ◽  
Vol 16 (28) ◽  
pp. 5113-5118 ◽  
Author(s):  
Arumugavel Murugan ◽  
Koteswar Rao Gorantla ◽  
Bhabani S. Mallik ◽  
Duddu S. Sharada

An efficient C3–H functionalization of indazole has been demonstrated. Notably, this method involves chelation-free radical C–H nitration on 2H-indazole. The radical mechanism was confirmed by control experiments and quantum chemical calculations. The synthetic utility has been proven by the synthesis of bio-relevant benzimidazoindazoles via reductive cyclization.

Fuel ◽  
2021 ◽  
Vol 290 ◽  
pp. 119999
Author(s):  
Xiao Ye ◽  
Anyao Jiao ◽  
Hai Zhang ◽  
Bin Chen ◽  
Sha Wang ◽  
...  

2019 ◽  
Vol 21 (48) ◽  
pp. 26324-26332 ◽  
Author(s):  
Emily E. Claveau ◽  
Evangelos Miliordos

Our high-level calculations show that high-spin NbO electronic states facilitate the methane to methanol transformation via a very efficient radical mechanism, as opposed to the [2+2] mechanism observed for the rest of the low-lying states.


1992 ◽  
Vol 47 (12) ◽  
pp. 1775-1778 ◽  
Author(s):  
Snezhana Bakalova ◽  
Ivanka Kavrakova

The absorption and luminescence properties of 6-acetyl-2,3-dihydro-4(1H)-quinolinone are described and compared to those of the parent 2,3-dihydro-4(1H)-quinolinone. The character of the electronic transitions is determined by PPP quantum chemical calculations.An N-acyl migration leading to the formation of 6-acetyl-2,3-dihydro-4(1H)-quinolinone takes place upon UV irradiation or heating with polyphosphoric acid of 1-acetyl-2,3-dihydro-4-(1H)-quinolinone. A radical mechanism of the photochemical rearrangement is proposed.


2006 ◽  
Vol 62 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Agnieszka Plutecka ◽  
Marcin Hoffmann ◽  
Urszula Rychlewska ◽  
Zdzisław Kucybała ◽  
Jerzy Pączkowski ◽  
...  

2-Oxo-2,3-dihydro-1H-imidazo[1,2-a]pyridinium bromide and its C3-substituted derivatives have been synthesized and structurally characterized by X-ray crystallography and quantum chemical calculations. Their potential as photoinitiators for free-radical polymerization has been investigated experimentally and compared with theoretical results. It has been established that the course of the reaction that introduces the substituted benzylidene group to the imidazole ring is different in the protic and dipolar aprotic solvents, and also depends on the character of the substituent, as the energy change in the reaction favours either R 1 R 2C=CHR 3 or R 1 R 2CH—CH(OCH3)R 3 formation.


2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.


2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.


2019 ◽  
Author(s):  
Przemyslaw Rzepka ◽  
Zoltán Bacsik ◽  
Andrew J. Pell ◽  
Niklas Hedin ◽  
Aleksander Jaworski

Formation of CO<sub>3</sub><sup>2-</sup> and HCO<sub>3</sub><sup>-</sup> species without participation of the framework oxygen atoms upon chemisorption of CO<sub>2</sub> in zeolite |Na<sub>12</sub>|-A is revealed. The transfer of O and H atoms is very likely to have proceeded via the involvement of residual H<sub>2</sub>O or acid groups. A combined study by solid-state <sup>13</sup>C MAS NMR, quantum chemical calculations, and <i>in situ</i> IR spectroscopy showed that the chemisorption mainly occurred by the formation of HCO<sub>3</sub><sup>-</sup>. However, at a low surface coverage of physisorbed and acidic CO<sub>2</sub>, a significant fraction of the HCO<sub>3</sub><sup>-</sup> was deprotonated and transformed into CO<sub>3</sub><sup>2-</sup>. We expect that similar chemisorption of CO<sub>2</sub> would occur for low-silica zeolites and other basic silicates of interest for the capture of CO<sub>2</sub> from gas mixtures.


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