Facile light-initiated radical generation from 4-substituted pyridine under ambient conditions

2020 ◽  
Vol 56 (51) ◽  
pp. 6937-6940
Author(s):  
Ami Nakayama ◽  
Haru Kimata ◽  
Kazuhiro Marumoto ◽  
Yohei Yamamoto ◽  
Hiroshi Yamagishi
Keyword(s):  
Colour Change ◽  
Stable Radical ◽  
Pyridine Derivative ◽  
Ambient Conditions ◽  
Radical Species ◽  
Radical Generation

A facile photogeneration of a stable radical species from a 4-substituted pyridine derivative under ambient conditions is achieved. The radical generation reaction accompanies visible colour change into green and is repeatable multiple times.

Mechanism of stable radical generation in aromatic polyamides on exposure to nitrogen dioxide

2006 ◽  
Vol 91 (10) ◽  
pp. 2423-2428 ◽  
Author(s):  
T.V. Pokholok ◽  
I.S. Gaponova ◽  
E.Ya. Davydov ◽  
G.B. Pariiskii
Keyword(s):  
Nitrogen Dioxide ◽  
Stable Radical ◽  
Aromatic Polyamides ◽  
Radical Generation

A Stable Radical Species from Facile Oxygenation of meso-Free 5,10,20,25-Tetrakis(pentafluorophenyl)-Substituted [26]Hexaphyrin(1.1.1.1.1.1)

2008 ◽  
Vol 47 (50) ◽  
pp. 9661-9665 ◽  
Author(s):  
Taro Koide ◽  
Gengo Kashiwazaki ◽  
Masaaki Suzuki ◽  
Ko Furukawa ◽  
Min-Chul Yoon ◽  
...  
Keyword(s):  
Stable Radical ◽  
Radical Species

scholarly journals Fourth stable radical species in X-irradiated solid-state sucrose

2016 ◽  
Vol 18 (16) ◽  
pp. 10983-10991 ◽  
Author(s):  
Jevgenij Kusakovskij ◽  
Ignacio Caretti ◽  
Sabine Van Doorslaer ◽  
Freddy Callens ◽  
Henk Vrielinck
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Stable Radical ◽  
Radical Species

Stable radical species in X-irradiated sucrose has been studied using multi-frequency EPR, endor at Q-band and DFT calculations.

Mechanochemical generation of stable radical species. Oxidation of pyrocatechols

1997 ◽  
Vol 272 (5-6) ◽  
pp. 399-404 ◽  
Author(s):  
D.S. Tipikin ◽  
Ya.S. Lebedev ◽  
A. Rieker
Keyword(s):  
Stable Radical ◽  
Radical Species

scholarly journals Direct Photoexcitation of Benzothiazolines: Acyl Radical Generation and Application to Access Heterocycles

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6843
Author(s):  
Xiang-Kui He ◽  
Juan Lu ◽  
Hai-Bing Ye ◽  
Lei Li ◽  
Jun Xuan
Keyword(s):  
Natural Products ◽  
Radical Cyclization ◽  
Acyl Radical ◽  
Radical Species ◽  
Complex Molecules ◽  
Radical Generation

An acyl radical generation and functionalization strategy through direct photoexcitation of benzothiazolines has been developed. The formed acyl radical species can either be trapped by quinoxalin-2-ones to realize their C(3)-H functionalization or trigger a cascade radical cyclization with isonitriles to synthesise biologically important phenanthridines. The synthetic value of this protocol can be further illustrated by the modification of quinoxalin-2-ones, containing important natural products and drug-based complex molecules.

scholarly journals The effect of pressure on the crystal structure of bianthrone

2011 ◽  
Vol 67 (3) ◽  
pp. 226-237 ◽  
Author(s):  
Russell D. L. Johnstone ◽  
David Allan ◽  
Alistair Lennie ◽  
Elna Pidcock ◽  
Rafael Valiente ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Ambient Pressure ◽  
Colour Change ◽  
Ambient Conditions ◽  
Effect Of Pressure ◽  
Intermolecular Contacts ◽  
Pressure Phase ◽  
Considerable Strain

Bianthrone [10(10-oxoanthracen-9-ylidene)anthracen-9-one] consists of two tricyclic anthraceneone units connected by a carbon–carbon double bond. Crystals of the form obtained under ambient conditions are yellow and contain folded centrosymmetric conformers in which the central ring of the anthraceneone unit is non-planar. When hydrostatic pressure is applied the crystals assume a red colouration which gradually deepens as pressures increases. The colour change is limited in extent to the surface of the crystals, the bulk remaining yellow. Comparison of high-pressure, single-crystal UV–vis spectra and powder diffraction data demonstrate that the colour change is associated with the formation of a polymorph containing a conformer in which the tricyclic fragments are planar and the molecule is twisted about the central C—C bond. Single-crystal diffraction data collected as a function of pressure up to 6.5 GPa reveal the effect of compression on the yellow form, which consists of layers of molecules which stack along the [010] direction. The structure remains in a compressed form of the ambient-pressure phase when subjected to hydrostatic pressure up to 6.5 GPa, and the most prominent effect of pressure is to push the layers closer together. PIXEL calculations show that considerable strain builds up in the crystal as pressure is increased with a number of intermolecular contacts being pushed into destabilizing regions of their potentials.

scholarly journals Bacillus megaterium Has Both a Functional BluB Protein Required for DMB Synthesis and a Related Flavoprotein That Forms a Stable Radical Species

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e55708 ◽  
Author(s):  
Hannah F. Collins ◽  
Rebekka Biedendieck ◽  
Helen K. Leech ◽  
Michael Gray ◽  
Jorge C. Escalante-Semerena ◽  
...  
Keyword(s):  
Bacillus Megaterium ◽  
Stable Radical ◽  
Radical Species

A Stable Radical Species from Facile Oxygenation of meso-Free 5,10,20,25-Tetrakis(pentafluorophenyl)-Substituted [26]Hexaphyrin(1.1.1.1.1.1)

2008 ◽  
Vol 120 (50) ◽  
pp. 9807-9811 ◽  
Author(s):  
Taro Koide ◽  
Gengo Kashiwazaki ◽  
Masaaki Suzuki ◽  
Ko Furukawa ◽  
Min-Chul Yoon ◽  
...  
Keyword(s):  
Stable Radical ◽  
Radical Species

scholarly journals Metal-independent ribonucleotide reduction powered by a DOPA radical in Mycoplasma pathogens

2018 ◽  
Author(s):  
Vivek Srinivas ◽  
Hugo Lebrette ◽  
Daniel Lundin ◽  
Yuri Kutin ◽  
Margareta Sahlin ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Ribonucleotide Reductase ◽  
De Novo ◽  
Spectroscopic Characterization ◽  
Radical Species ◽  
Metal Site ◽  
Absolute Requirement ◽  
Radical Generation

AbstractRibonucleotide reductase (RNR) catalyzes the only known de-novo pathway for production of all four deoxyribonucleotides required for DNA synthesis. In aerobic RNRs, a di-nuclear metal site is viewed as an absolute requirement for generating and stabilizing an essential catalytic radical. Here we describe a new group of RNRs found in Mollicutes, including Mycoplasma pathogens, that possesses a metal-independent stable radical residing on a modified tyrosyl residue. Structural, biochemical and spectroscopic characterization reveal a stable DOPA radical species that directly supports ribonucleotide reduction in vitro and in vivo.The cofactor synthesis and radical generation processes are fundamentally different from established RNRs and require the flavoprotein NrdI. Several of the pathogens encoding this RNR variant are involved in diseases of the urinary tract and genitalia. Conceivably, this remarkable RNR variant provides an advantage under metal starvation induced by the immune system. We propose that the new RNR subclass is denoted class Ie.

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