The Meyer Reaction of Phenylnitromethane in Acid. II. Reactions in Acid of Benzonitrile Oxide and Benzohydroxamic Acid

Edward, John T.; Tremaine, P. H.

doi:10.1139/v71-583

Cited by 12 publications

(2 citation statements)

References 9 publications

(13 reference statements)

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“…They are the thermodynamically unfavorable tautomers of nitroalkanes, − as illustrated by the 14 kcal/mol energy difference (G2 theory) between the nitromethane tautomers. Still, nitronic acids play an important role as reactive intermediates in many redox, photochemical, and pyrolysis processes, − and in syntheses such as the Nef and Victor Meyer reactions and by inter- 8 or intramolecular 9 hydrogen bonding .…”

Section: Introductionmentioning

confidence: 99%

Keto ⇌ Enol, Imine ⇌ Enamine, and Nitro ⇌aci-Nitro Tautomerism and Their Interrelationship in Substituted Nitroethylenes. Keto, Imine, Nitro, and Vinyl Substituent Effects and the Importance of H-bonding

Lammertsma

Bharatam

2000

J. Org. Chem.

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Tautomeric isomers and conformers of 2-nitrovinyl alcohol (1), 2-nitrovinylamine (2), and 1-nitro-propene (3) are reported at the MP2 and B3LYP levels of theory, using the 6-31G* basis set, with energy evaluation at B3LYP/6-311+G** and G2MP2. The nitroalkenes are the global minima on their respective potential energy surfaces. The barriers for the concerted 1,5-H transfer to the corresponding nitronic acids amount to only 5.0 kcal/mol for 1, 13.2 kcal/mol for 2, and a sizable 37.8 kcal/mol for 3. Whereas the aci-nitro tautomer of 2-nitrovinyl alcohol is easily accessible, beta-iminonitronic acid has little kinetic stability. H-bonding is a strong stabilizing factor in these nitroalkenes, estimated at 7.0 and 3.7 kcal/mol for the OH and NH2 derivatives, respectively, while its stabilization in their nitronic acids amounts to as much as 13 kcal/mol. The H-bonds are evident from the very short O...H and N...H distances and are characterized by bond critical points. The NO2 substituent effect of about 11.4 kcal/mol at G2MP2 on both the classical keto <==> enol and imine <==> enamine tautomeric processes stabilizes the nitroethylene derivatives. The keto, imine, and vinyl substituent effects at G2MP2 on the nitro <==> aci-nitro tautomeric process are also determined as are their pi-resonance components. The substituents have a large influence on the ionization energies of the nitroethylene derivatives.

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Section: Introductionmentioning

confidence: 99%

Keto ⇌ Enol, Imine ⇌ Enamine, and Nitro ⇌aci-Nitro Tautomerism and Their Interrelationship in Substituted Nitroethylenes. Keto, Imine, Nitro, and Vinyl Substituent Effects and the Importance of H-bonding

Lammertsma

Bharatam

2000

J. Org. Chem.

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“…At pH <8, the reaction with 3 (Ar = p-MeOCgH4) is inde-ArC=NOH ArC=NO' prepared by independent synthesis from the ethyl benzoate and hydroxy lamine2). Under the conditions used to study the kinetics, no detectable further hydrolysis of the benzohydroxamic acids occurs (although it is well established that in concentrated acid or base 6 hydrolyse to benzoic acids and hydroxylamine). 3 The formation of 6 contrasts with previous reports of complex products,4'5 although Edwards and Tre-maine6 also observed the quantitative formation of benzohydroxamic acids 6 on hydrolysis of chlorides 1 under mild conditions (aqueous sodium bicarbonate).…”

Section: Resultsmentioning

confidence: 99%

Reactivity of 1,3-dipoles in aqueous solution. 2. Stereospecific reactions of benzonitrile oxides with oxygen, carbon, and nitrogen nucleophiles

Dignam¹,

Hegarty²,

Quain³

1978

J. Org. Chem.

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TheNef Reaction

Pinnick

1990

Organic Reactions

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The Nef reaction is usually defined as the conversion of a primary or secondary nitroalkane into the corresponding carbonyl compound. This reaction was reported by the Swiss chemist J. U. Nef in 1894. Hydrochloric and sulfuric acid give the same result. The conversion of a nitro group to a carbonyl group has become an important synthetic tool because of the ease of preparation of substituted nitro compounds by condensation of nitroalkanes with aldehydes (the Henry reaction), conjugate addition of nitroalkanes to electrophilic alkenes, or carbon alkylation of the dianion of primary nitroparaffins. The Nef reaction is one of the better examples of “umpolung” reactivity in which the original nitro compound anion functions as an acyl anion equivalent. This chapter discusses the Nef reaction and modifications of the original process that extend the variety of compounds which are useful as substrates. Each modification is considered according to general mechanistic type and is organized in a “reagent” approach. The Tabular Survey lists all known examples of both the Nef reaction and these modifications so that specific comparison of methods can be made.

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The Meyer Reaction of Phenylnitromethane in Acid. II. Reactions in Acid of Benzonitrile Oxide and Benzohydroxamic Acid

Cited by 12 publications

References 9 publications

Keto ⇌ Enol, Imine ⇌ Enamine, and Nitro ⇌aci-Nitro Tautomerism and Their Interrelationship in Substituted Nitroethylenes. Keto, Imine, Nitro, and Vinyl Substituent Effects and the Importance of H-bonding

Keto ⇌ Enol, Imine ⇌ Enamine, and Nitro ⇌aci-Nitro Tautomerism and Their Interrelationship in Substituted Nitroethylenes. Keto, Imine, Nitro, and Vinyl Substituent Effects and the Importance of H-bonding

Reactivity of 1,3-dipoles in aqueous solution. 2. Stereospecific reactions of benzonitrile oxides with oxygen, carbon, and nitrogen nucleophiles

TheNef Reaction

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