74663-99-3Relevant academic research and scientific papers
Rhodium(III)-catalyzed regioselective C–H nitrosation/annulation of unsymmetrical azobenzenes to synthesize benzotriazole N-oxides via a RhIII/RhIII redox-neutral pathway
Zhang, Yuanfei,Chen, Zhe-Ning,Su, Weiping
supporting information, (2021/05/19)
A Rh(III)-catalyzed regioselective C–H nitrosation/annulation reaction of unsymmetrical azobenzenes with [NO][BF4] has been developed to achieve high-yielding syntheses of benzotriazole N-oxides with excellent functional group tolerance. Computational studies have revealed that this oxidative C–H functionalization reaction involves an interesting redox-neutral Rh(III)/Rh(III) pathway without the change of Rh oxidation state.
Nitrosation of aryl and heteroaryltrifluoroborates with nitrosonium tetrafluoroborate
Molander, Gary A.,Cavalcanti, Livia N.
experimental part, p. 4402 - 4413 (2012/06/18)
Organotrifluoroborates have emerged as an alternative to toxic and air- and moisture-sensitive organometallic species for the synthesis of functionalized aryl and heteroaryl compounds. It has been shown that the trifluoroborate moiety can be easily converted into a variety of different substituents in a late synthetic stage. In this paper, we disclose a mild, selective, and convenient method for the ipso-nitrosation of organotrifluoroborates using nitrosonium tetrafluoroborate (NOBF4). Aryl- and heteroaryltrifluoroborates were converted into the corresponding nitroso products in good to excellent yields. This method proved to be tolerant of a broad range of functional groups.
Photochemistry and thermal decarboxylation of α-phosphoryloxy-p- nitrophenylacetates
Corrie, John E. T.,Munasinghe, V. Ranjit N.,Rudbeck, Maria,Barth, Andreas
experimental part, p. 1089 - 1096 (2010/07/15)
α-Carboxy-4-nitrobenzyl phosphate 4 and its derived monomethyl phosphate ester 5 were synthesized and purified by anion-exchange chromatography. A gradient of LiCl was necessary for elution of the anion-exchange column to avoid unexpected thermal decarbox
Chemistry of photogenerated α-hydroxy-p-nitrobenzyl carbanions in aqueous solution: Protonation vs. disproportionation
Morrison, James,Wan, Peter,Corrie, John E.T.,Munasinghe, V. Ranjit N.
, p. 586 - 597 (2007/10/03)
The photochemistry of p-nitrobenzyl derivatives 6-10 has been studied in aqueous solution as a function of pH, using product analysis, UV-vis spectrophotometry, and laser flash photolysis (LFP). The compounds were chosen with the aim of further exploring the propensity of these systems to give rise to α-hydroxy-p-nitrobenzyl carbanions on photolysis, and to study their mechanisms of subsequent reaction, α-Hydroxy-substituted carbanions are anions that cannot be readily formed using thermal routes but which are believed to have some interesting chemistry. Three methods were employed for photogenerating these carbanions: (i) decarboxylation; (ii) retro-Aldol reaction; and (iii) carbon acid deprotonation. All three methods proved to be successful using the p-nitrobenzyl chromophore. Photogenerated α-hydroxy-p-nitrobenzyl carbanions react via disproportionation, giving rise to oxidized and reduced products; simple protonation of the anion was undetectable.
Methylenecyclopropane Rearrangement as a Probe for Free Radical Substituent Effects. σ·Values for Potent Radical-Stabilizing Nitrogen-Containing Substituents
Creary, Xavier,Engel, Paul S.,Kavaluskas, Natasha,Pan, Li,Wolf, Allison
, p. 5634 - 5643 (2007/10/03)
A series of nitrogen-containing 2-aryl-3,3-dimethylmethylenecyclopropanes have been prepared and rearrangement rates to the corresponding 2-arylisopropylidenecyclopropanes have been measured. These rates are dependent on the nature of the nitrogen-containing group in the para-position of the aryl group. Rearrangement rates have been used to calculate σ· values, which are a measure of the radical stabilizing ability of the substituent. Groups such as p-N=N-Bu-t, p-CH=N-Bu-t, p-NH2, p-CH=N-OH, and p-CH=N-OCH3, are "good" radical stabilizers. We have also classified groups such as p-CH=N-NMe2, p-N=N-Ph, p-N=N(O)-Bu-t, p-CH=N(O)-Bu-t, and p-CH=N-O- M+, which have an extraordinarily large radical stabilizing effect, as "Super Stabilizers". These substituents stabilize the transition state of the methylenecyclopropane rearrangement by extensive spin delocalization. In the case of the latter three substituents, nitroxyl type stabilization is proposed. Density functional calculations (B3LYP/6-31G*) have been carried out on a series of nitrogen-containing substituted benzylic radicals. Rates of the methylenecyclopropane rearrangement correlate with radical stabilization energies (ΔE) determined from an isodesmic reaction of substituted benzylic radicals with toluene. These calculations confirm substantial spin delocalization onto the nitrogen-containing substituents on the para-position of the benzylic radical.
Kinetics and Mechanism of the Catalytic Reduction of Sulphonyl> Acetic Acid in Alkaline Dioxane-Water Media
Riad, Y.,Asaad, A. N.,El-Nahas, Hind M.,Madkour, A. E.
, p. 353 - 364 (2007/10/03)
The reaction of sulphonyl>acetic acid with sodium hydroxide in aqueous-idoxane media leads to the reduction of the nitro group with the formation of 4,4'-diformylazoxybenzene and 4,4'-dicarboxyazoxybenzene as the main products. The reaction mechanism was verified by trapping the intermediates namely (α-hydroxy-4-nitrosobenzyl)sulphonyl acetic acid and 4-nitrosobenzaldehyde as well as by the H/D exchange of the active methylene group of the parent compound. The kinetics of the reaction with excess alkali in different dioxane-water mixture were studied spectrophotometrically. The rate constants of the two consecutive steps of the reaction and their activation thermodynamic parameters were calculated and are discussed on the basis of the solvent composition of the media. A comparison of the reactivity with that of the corresponding sulphide is also discussed.
