The Nitration of Activated Carbonyl Compounds in a Two-phase System

Laikhter, A. L.; Кислый, В. П.; Семенов, В. В.

doi:10.1070/mc1993v003n01abeh000203

Cited by 19 publications

(12 citation statements)

References 9 publications

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“…The following trifluoromethylsulfonylation gave the 4-(triflyloxy)furoxan, which was converted to α-nitrocyano compound 28 upon treatment with Pd(PPh 3 ) 4 . Although multiple steps are required, the mild reaction parameters enable access to a nitrocyanomethyl group, a relatively rare functional group in literatures. , Compounds 29 – 31 , a molecule class of isoxazole and isoxazoline with an adjacent oxime moiety, could be synthesized by heating a mixture of 3e and 1,3-dipolarophile, alkyne, and alkene according to the relevant literature . Isoxazole 32 , lacking the oxime group versus 29 , could be generated from the same starting furoxan 3e by changing the solvent .…”

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confidence: 99%

Modular Synthesis of Carbon-Substituted Furoxans via Radical Addition Pathway. Useful Tool for Transformation of Aliphatic Carboxylic Acids Based on “Build-and-Scrap” Strategy

et al. 2020

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Utilizing radical chemistry, a new general C–C bond formation on the furoxan ring was developed. By taking advantage of the lability of furoxans, a wide variety of transformation of the synthesized furoxans have been demonstrated. Thus, this developed methodology enabled not only the modular synthesis of furoxans but also short-step transformations of carboxylic acids to a broad range of functional groups.

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confidence: 99%

Modular Synthesis of Carbon-Substituted Furoxans via Radical Addition Pathway. Useful Tool for Transformation of Aliphatic Carboxylic Acids Based on “Build-and-Scrap” Strategy

et al. 2020

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“…The kinetics of disappearance of N dinitromethylazoles in 89.2% H 2 SO 4 containing KNO 3 (1.15 mol L -1 ) was studied by UV spectroscopy at 20 °C. The concentration of N dinitromethylazoles (0.02-0.03 mol L -1 ) was con siderably lower, which made it possible to use a first order equation for the calculation of the kinetics of their de composition.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of nitration of nitrogen-containing heterocyclic N-acetonyl derivatives. General approach to the synthesis of N-dinitromethylazoles

et al. 2009

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A general synthetic procedure for the synthesis of N dinitromethyl derivatives of nitrogen containing heterocycles has been developed. The procedure includes the destructive nitration of heterocyclic N acetonyl derivatives of tetrazoles, 1,2,4 and 1,2,3 triazoles, pyrazoles, imid azoles and their bicyclic analogs, as well as imides of carboxylic and sulfonic acids and substitut ed hydrazines with mixtures of sulfuric and nitric acids. The kinetic study of the reaction mechanism was performed using UV and NMR spectroscopy. It was found that the NO 2 groups were sequentially introduced into the methylene fragment by the addition of the nitronium ion to multiple bonds of intermediate enols followed by hydrolysis of the acetyl moiety. The rate and direction of the enolization (due to the CH 2 and CH 3 groups) of the N acetonyl com pounds in sulfuric acid solutions were determined by the study of the deuterium exchange kinetics. The synthesis of the N dinitromethyl compounds is complicated by side reactions, such as the decomposition of intermediate α nitroketone, the nitration of the methyl group in the acetonyl moiety, and the nitration of the dinitromethyl products to trinitromethyl derivatives.Nitration with acidic nitrating mixtures of the active methylene moiety of carbonyl structures (1) to form dini tromethyl compounds (destructive nitration) was studied. 1 It can be assumed that the process proceeds through the formation of dinitromethylene derivatives of carbonyl compounds (1´), whose hydrolysis affords dinitromethyl compounds (2) (Scheme 1). Scheme 1In these works, the nitration conditions were selected empirically without revealing regularities of the reaction and its mechanism, which impedes the optimization of synthesis of dinitromethyl compounds.In the present work, in order to detail processes of destructive nitration of active methylene compounds, 2-9 we studied the mechanism, kinetics, and conditions of this reaction using easily accessible N acetonylazoles 10 as an example. Results and DiscussionWe have earlier 11 studied by 13 С NMR spectroscopy the state of N acetonylazoles in an H 2 SO 4 solution for the lowest basicity tetrazole derivatives. It turned out that on going from solutions in neutral solvents to solutions in concentrated H 2 SO 4 the direct spin spin coupling (SSC) constants ( 1 J C,H ) for the N-CH 2 group and СH cycle increase by 4-5 and 16-18 Hz for 1 and 2 acetonyltet razoles and 5 methyltetrazole analogs, respectively. The same increase in 1 J C,H in neutral media is characteristic of N acetonyltetrazolium salts 4 compared to non quater nized N acetonyltetrazoles 3: these constants for the carbon atoms in the N-CH 2 , N-Me, and C-Me fragments in crease by 4-5 Hz, whereas for the С 5 cycle they increase by 15-20 Hz. 11 It follows from this that the N acetonyl derivatives of tetrazole and 5 methyltetrazole in concen trated H 2 SO 4 are protonated to the nitrogen atom of the cycle. 12 Even in the case of low basicity nitrotetrazole (pK BH + = -9.26), 13 the corresponding ketone is p...

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“…Therefore, we considered the electron-withdrawing nitro group to be useful for substrate activation. Nitration of β-keto esters was readily accomplished by Laikhter's method, 24 using two-phase reaction conditions (dichloromethane/sulfuric acid) to afford DEAD-NO 2 . The electron-withdrawing properties of the nitro group of DEAD-NO 2 prevent the formation of polynitrated keto esters.…”

Section: Transacylation Of An α-Nitro-β-keto Ester 22mentioning

confidence: 99%

Development of a Pseudo-Intramolecular Process

Nishiwaki

2016

Synthesis

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A pseudo-intramolecular process is developed. Compounds having both an acidic hydrogen and a functionality serve as substrates in the present method, and immediately form an ammonium salt after the addition of an amine. When the amine is liberated under mild equilibrium conditions, both the nucleophilic amine and the electrophilic substrate are in proximity and react efficiently under mild reaction conditions. Although the reaction actually concerns an intermolecular process, it proceeds as if it were an intramolecular process. Thus, this method represents a novel procedure for synthesizing polyfunctionalized compounds that are not easily available via alternative methods. The transacylation using α-arylated or α-nitrated β-keto esters facilitates the chemoselective or regioselective acylation of amines. α-Nitro-δketo nitriles also serve as substrates for the present reaction to afford 1,4-dihydropyridines, diazepines, pyridazines, and diazabicyclic compounds, efficiently. 1 Introduction 2 Transacylation of an α-Arylated β-Keto Ester 3 Synthesis of Unsymmetrical Malonates 4 Transacylation of an α-Nitro-β-keto Ester 5 Reaction of an α-Nitro-δ-keto Nitrile with Amines 6 Reaction of an α-Nitro-δ-keto Nitrile with Hydrazines 7 Reactions of α-Nitro-δ-keto Nitriles with Diamines 8 Reactions of α-Nitro-δ-keto Esters with Diamines 9 Conclusion

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The Nitration of Activated Carbonyl Compounds in a Two-phase System

Cited by 19 publications

References 9 publications

Modular Synthesis of Carbon-Substituted Furoxans via Radical Addition Pathway. Useful Tool for Transformation of Aliphatic Carboxylic Acids Based on “Build-and-Scrap” Strategy

Modular Synthesis of Carbon-Substituted Furoxans via Radical Addition Pathway. Useful Tool for Transformation of Aliphatic Carboxylic Acids Based on “Build-and-Scrap” Strategy

Mechanism of nitration of nitrogen-containing heterocyclic N-acetonyl derivatives. General approach to the synthesis of N-dinitromethylazoles

Development of a Pseudo-Intramolecular Process

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