The interaction of aromatic nitro-compounds with bases

Buncel, Erwin; Norris, A. R.; Russell, K. E.

doi:10.1039/qr9682200123

Cited by 115 publications

(58 citation statements)

References 3 publications

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“…Pseudobase formation by a nucleophilic addition to heteroaromatic cations is closely related to additions of OH -or RO -ions to benzenoid compounds bearing strongly electron withdrawing groups, such as NO 2 , resulting in formation of Φ-complexes termed Meisenheimer complexes [81][82][83] .…”

Section: Covalent Additions To Heterocyclic Ringsmentioning

confidence: 99%

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Zuman¹

2002

Arkivoc

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In this review are discussed equilibria involved in nucleophilic additions of H 2 O, HO -, ROH, and RO -(where R is an alkyl) to compounds containing carbonyl and azomethine bonds. These reactions result in a formation of covalent bonds between the heteroatom of the nucleophile and the carbon of the carbonyl double bond. After a brief summary of reactions resulting in additions to aliphatic carbonyl compounds, attention is paid to additions to benzaldehydes and formyl aromatic heterocycles. Equilibria involving additions to pyridoxal and some related compounds are dealt with in some detail. Discussion of additions of stated nucleophiles to azomethine bonds is practically restricted to additions to C=N bonds in heterocyclic rings. The reactivity of nucleophiles in such additions depends on the number of heteroatoms (in particular nitrogen) in the attacked ring, as well as on the number and position of substituents in such rings. In polynuclear compounds the reactivity depends on the number and kind of annelled rings, on the number and mutual position of heteroatoms and on the kind, number and position of substituents. In particular additions to pyrimidines, quinazolines, 1,2,4-and 1,3,5-triazines, pteridines and other heterocycles with four nitrogens, as well as 8-azapurines are mentioned.

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Section: Covalent Additions To Heterocyclic Ringsmentioning

confidence: 99%

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Zuman¹

2002

Arkivoc

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“…A variety of o-complexes which are For personal use only. closely analogous to 3 and 4 have been characterized by nmr as well as uv-vis spectroscopy (1)(2)(3)(4)(5)(6)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). However, there is as yet no unambiguous uv-vis or nmr evidence for the carbanions 5 and 6.…”

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confidence: 99%

“…The capability of aromatic nitro compounds to interact with bases by a number of mechanisms has led to controversy regarding the occurrence and importance of nuclear hydrogen exchange (1)(2)(3)(4)(5)(6). In the case of 1,3-dinitrobenzene (DNB), the species that have been postulated to be formed at different times through action of a base Y: are a charge transfer complex 1, a radical anion 2, covalent adducts (also known as Meisenheimer or o-complexes) 3 and 4, as well as the carbanions 5 and 6 which are the presumed intermediates in proton exchange.…”

mentioning

confidence: 99%

Hydrogen exchange studies. XIV. Kinetics and mechanism of base-catalyzed hydrogen exchange in 1,3-dinitrobenzene in aqueous dimethylformamide and relationship with σ-complex formation

Buncel¹,

Zabel²

1981

Can. J. Chem.

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ERWIN BUNCEL and ALLEN W. ZABEL. Can. J . Chem. 59, 3177 (1981). Kinetic data have been evaluated for hydrogen exchange in 1,3-dinitrobenzene (DNB), occurring at the 2-position, in dimethylformamide (DMF) -D,O mixtures containing deuteroxide ion. The pseudo first order rate constants for exchange, k,,,. show inverse dependence on the initial DNB concentration, which can be quantitatively related to the extent of o-complex formation in these systems. The profile fork,,,, as function of medium compositio~l exhibits a maximum at ca. 70 mol% DMF, and E ,~, for o-complex formation reaches a plateau at about the same medium composition. The equilibrium constants for o-complex formation, K,, are used to calculate the free. or uncomplexed, deuteroxide ion concentrations, which then allow one to calculate k 2 . the second order rate constants for exchange. The k, values show a uniformly increasing tendency with increased DMF content. Correlations with medium basicity are examined, and the nature of the log k, and log K, vs. H-plots afford insight into the origin of the medium dependence of proton exchange. The results of the present study are consistent with the cr-complex being an unreactive form of the substrate towards exchange, which occurs via uncomplexed DNB present in small concentration. The study also rules out the possibility that the colored species present in these systems is the carbanion formed on deprotonation of DNB.ERWIN BUNCEL et ALLEN W . ZABEL. Can. J. Chem. 59. 3177 (1981). O n a evalue les donnees cinetiques de l'echange d'hydrogene se produisant en position 2 du dinitro-1,3 benzene (DNB) dans des melanges de dimethylformamide (DMF) -D,O contenant I'ion deuteroxyde. L a constante de vitesse d e pseudo ordre un de l'echange k,,,, revele un effet inverse de la concentration initiale de DNB qui peut etre relie quantitativement aux taux deformation du complexe o dans ces systemes. 1.e profil de k,,, en fonction de la composition du milieu montre un maximum pour environ 70 molR de DMF et le E, , , de la formation du complexeo atteint un plateau pour environ la meme composition du milieu. On a utilise la constante d'equilibre d e la formation du complexe o K,, pour calculer les concentrations de I'ion deuteroxyde libre. ou non complexe qui permettent de calculer k, la constante d e vitesse d'ordre deux de I'echange. Les valeurs de k2 montrent une tendance d'augmentation uniforme avec la teneur en DMF. On a examine les correlations avec la basicite du milieu; la nature des courbes de log k, et log K, en fonction de H-fournit des renseignements sur I'origine de l'effet du milieu lors de I'echange de proton. Les resultats de la presente etude sont en accord avec un complexe o qui ne donnerait pas de reaction d'echange celui-ci se produisant par I'intermediaire du DNB non complexe present a une concentration faible. L'etude ecarte egalement la possibilite que l'espece coloree presente dans ces systemes soit le carbanion forme par la protonation du DNB.[Traduit par le journal]

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“…There are various interactions depending upon the degree to which the base participate through its unshared electron pair with the nitro compounds. 11) In the present study, perindopril behaves as a base owing to the presence of -NH group in its structure. Addition of CDNB to perindopril in DMSO yielded the 1-substituted Meisenheimer complex which absorbs maximally at 420 nm.…”

Section: Resultsmentioning

confidence: 99%

Optimized and Validated Initial-Rate Method for the Determination of Perindopril Erbumine in Tablets

Rahman

Anwar

Kashif

2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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The interaction of aromatic nitro-compounds with bases

Abstract: SO3--CN-CH3NH-gH loN-Solvent Water Methanol Ethanol Dime t h yl formami de Acetone Ethanol Water Chloroform Dimethyl sulphoxide Acetonitrile A, (mt-4 450 425 424 465 464 464 462 437 452 444 A2 (mI-4 475 (sh) 495 497 570 572 565 525

Cited by 115 publications

References 3 publications

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Hydrogen exchange studies. XIV. Kinetics and mechanism of base-catalyzed hydrogen exchange in 1,3-dinitrobenzene in aqueous dimethylformamide and relationship with σ-complex formation

Optimized and Validated Initial-Rate Method for the Determination of Perindopril Erbumine in Tablets

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