10229-64-8Relevant articles and documents
Multiplicity of reaction pathways in the processes of oxygen transfer to secondary amines by Mo(VI) and W(VI) peroxo complexes
Ballistreri, Francesco P.,Barbuzzi, Elena G. M.,Tomaselli, Gaetano A.,Toscano, Rosa M.
, p. 6381 - 6387 (1996)
Oxidation of N,N-benzylmethylamine, N,N-benzylisopropylamine, and N,N-benzyl-tert-butylamine by both anionic and neutral Mo(VI) and W(VI) oxodiperoxo complexes yields the corresponding nitrones quantitatively. The oxidation reactions employing anionic oxidants were performed in CHCl3 and follow second-order kinetics, first order with respect to the amine and to the oxidant. The data were rationalized on the basis of a rate-determining nucleophilic attack of the amine onto the peroxide oxygen of the oxidant, with a transition state in which N-O bond formation and O-O bond cleavage occur in a concerted way (electrophilic oxygen transfer mechanism). This attack yields the corresponding hydroxylamine, which then is furtherly oxidized to nitrone in a fast step. On the other hand, in the case of neutral oxidants 1H-NMR data as well as kinetic data indicate that amine coordinates the metal center replacing the original ligand HMPA and yields a new peroxo complex. For N,N-benzyl-tert-butylamine such a complex was isolated and characterized. These new peroxo complexes can themselves behave as electrophilic oxidants, transferring oxygen to external amine molecules through the same pathway followed by anionic oxidants, or can yield the reaction product by intramolecular oxidation of the coordinate amine. Measurements of added HMPA effects on oxidation rate would seem more consistent with the electrophilic oxygen transfer mechanism.
EPR Kinetic Evidence for Radical Intermediacy in the Oxidation of Secondary Amines to Nitrones by [Wo(O2)2OCOC5H4N]- [Bu4N+]
Ballistreri,Bianchini,Pinzino,Tomaselli,Toscano
, p. 2710 - 2715 (2000)
Oxidation reactions of N,N-benzylalkylamines by [WO(O2)2OCOC5H4N] -[Bu4N+] to nitrones were kinetically studied by UV and EPR techniques. The reactions follow a second-order rate law and the rate-determining step is a simple bimolecular attack of amine onto the peroxide oxygen of the peroxometal complex, which leads to the formation of the corresponding hydroxylamine. However, EPR measurements and iterative procedures point out that the reaction occurs through the intermediacy of aminoxyl radicals, formed by oxidation of hydroxylamine generated in situ in the rate-determining step, and subsequent oxidations of these radicals to nitrones by the starting peroxo complex. It is suggested that the oxidation of hydroxylamine to aminoxyl radical as well as the oxidation of aminoxyl radical to nitrone occurs through an electron transfer step associated with a proton transfer.
Aliphatic nitro compounds chemistry: oximes–nitrones tunable production through directed tandem synthesis
Kazemi, Foad,Ramdar, Moosa,Davarpanah, Jamal
, p. 353 - 362 (2019/01/25)
Abstract: Reduction of aliphatic nitro compounds in the presence of aldehydes and dialdehydes for tunable directed synthesis of oximes, nitrones, nitrone–oximes, and dinitrones was reported. The slow and nonselective reduction of aliphatic nitro compounds was directed by condensation of in situ prepared alkylhydroxylamines with aromatic aldehydes. Mononitrones and dinitrones were synthesized at reflux and at 55?°C conditions, respectively, in tetrahydrofuran using SnCl2?2H2O and Na2CO3. It was found that the presence of a catalytic amount of carboxylic acid such as 3-phenylpropanoic acid increases the yield of dinitrones versus nitrone–oxime and dioxime when dialdehydes were used as aldehyde source. Graphical abstract: [Figure not available: see fulltext.].
Stereoselective synthesis of fluoroalkenoates and fluorinated isoxazolidinones: N-substituents governing the dual reactivity of nitrones
Prakash, G.K. Surya,Zhang, Zhe,Wang, Fang,Rahm, Martin,Ni, Chuanfa,Iuliucci, Marc,Haiges, Ralf,Olah, George A.
supporting information, p. 831 - 838 (2014/01/23)
α-Fluoroalkenoates and 4-fluoro-5-isoxazolidinones are of vast interest due to their potential biological applications. We now demonstrate the syntheses of (E)-α-fluoroalkenoates and 4-fluoro-5-isoxazolidinones by the reactions between nitrones and α-fluoro-α-bromoacetate. By altering N-substituents in nitrones, (E)-α-fluoroalkenoates and 4-fluoro-5-isoxazolidinones can be achieved, respectively, with high chemo- and stereoselectivities. Experimental and computational studies have been conducted to elucidate the reaction mechanisms. Linear free energy relationship studies further revealed that the N-substituent effects are primarily of electronic origin. Copyright
