573-79-5Relevant articles and documents
The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
supporting information, p. 5680 - 5686 (2021/08/16)
Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
An exceptionally stable Ti superoxide radical ion: A novel heterogeneous catalyst for the direct conversion of aromatic primary amines to nitro compounds
Dewkar, Gajanan K.,Nikalje, Milind D.,Ali, Iliyas Sayyed,Paraskar, Abhimanyu S.,Jagtap,Sudalai
, p. 405 - 408 (2007/10/03)
A matrix-bound superoxide radical anion, generated by treating Ti(OR)4 (R =iPr, nBu) with H2O2, is a selective heterogeneous catalyst for the oxidation of anilines to the corresponding nitroarenes with 50 % aqueous H2O2 [Eq. (1)]. Yields of 82-98 % are obtained, even with anilines bearing electron-withdrawing substituents (R = NO2, COOH).
Electrosynthesis and in situ chemical rearrangement of o-nitrosobenzamides
Guilbaud-Criqui, A.,Moinet, C.
, p. 101 - 110 (2007/10/02)
Primary and secondary o-nitrosobenzamides can be prepared in a "redox" cell but are unstable in the solvent used for electrolysis (acetate buffer-alcohol).At room temperature N-aryl-2-nitrosobenzamides give 2-carboxyazobenzenes.N-alkyl-2-nitrosobenzamides decompose thermally into 2-methoxy or 2-ethoxycarbonylphenylhydrazones according to the alcohol used.Similarly, methyl benzoate (or ethyl benzoate) is obtained from 2-nitrosobenzamide.A possible mechanism involves an unstable heterocycle formed by the coupling of the two nitrogen atoms (nitroso and amide) followed by cleavage of the carbonyl-nitrogen bond resulting from nucleophilic attack of the solvent (water or alcohol). Key Words: flow cell electrosynthesis / 2-nitrosobenzamides / 2-carboxyazobenzenes / 2-alkoxycarbonylphenylhydrazones / indazol-3-one
