Acyl derivatives of hydroxylamine. XII. Dissociation constants of hydroxamic acids and their functional derivatives

Exner, Otto; Simon, Wendy M.

doi:10.1135/cccc19654078

Cited by 48 publications

(29 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There is a regular increase in basicity of 4X,3Y-NMBH anions as water content of the medium decreases. The p value in 80% methylcellusolve is 0.95 (40), which shows the same conclusion.…”

Section: Kineticssupporting

confidence: 73%

See 1 more Smart Citation

Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

Fountain¹,

Fountain²,

Michaels³

et al. 1991

Can. J. Chem.

View full text Add to dashboard Cite

. Can. J. Chem. 69,798 (1991).The rates of methyl transfer between benzohydroxamates and sulfonates show large Pnuc values (ca. 0.8) indicating much charge transfer to the C atom, similar to the results of N,N-dialkylaminofluorene anions. A small a effect shows that even in methyl substrates, with certain leaving groups, the effect is displayed. Investigation of the PI, shows that from the leaving group side of the reaction it is a normal SN2 reaction. Correlation of the reactivity with computed gas phase ionization potentials shows that desolvation of anions is probably not important. These results suggest an a-effect model that explains the larger size of the effect at carbonyl groups in terms of greater solvation of the charge transferred to the 0 atom. anions N,N-dialkylaminofluor&nes. Un faible effet a montre que, m&me avec des substrats mCthyles de certains nuclCofuges, on peut observer cet effet. Une Ctude du PI, montre que, par rapport au groupement nuclCofuge, il s'agit d'une reaction SN2 normale.Une corrClation de la rCactivitt avec les potentiels d'ionisation en phase gazeuse calculks montre que la dksolvatation des anions n'est probablement pas importante. Ces rCsultats suggkrent un modkle d'effet a qui explique l'importance plus grande de l'effet au niveau des groupements carbonyles en termes de plus grande solvatation de la charge qui est transfkrke i l'atome d'oxygkne.Mots clis : effet a , courbe de Bransted, potentiels d'ionisation, voltamktrie cyclique, PI,, P,,,, AMl, E4.[Traduit par la rCdaction]

show abstract

“…There is a regular increase in basicity of 4X,3Y-NMBH anions as water content of the medium decreases. The p value in 80% methylcellusolve is 0.95 (40), which shows the same conclusion.…”

Section: Kineticssupporting

confidence: 73%

“…126) was the indicator. The NMBH anions and conjugate acids are all known to follow Beer's law (40), see eq. [2].…”

Section: Kineticsmentioning

confidence: 99%

Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

Fountain¹,

Fountain²,

Michaels³

et al. 1991

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…The identity of ( 2 9 ) is established by its deep purple coloration with ferric chloride and by its isolation as the hydroxylammonium salt152LJ. Furthermore, (29) can be degraded by benzenesulfonyl chloride to anthranilic…”

Section: Structure and Alkylationmentioning

confidence: 99%

“…It has therefore been suggested that the contribution of the highly chromophoric isomer (28") is responsible for the intense color. In aqueous medium, the red solution of the salts of N-hydroxyphthalimide turns colorless due to their hydrolysis to (29). The identity of ( 2 9 ) is established by its deep purple coloration with ferric chloride and by its isolation as the hydroxylammonium salt152LJ.…”

Section: Structure and Alkylationmentioning

confidence: 99%

The Chemistry of Hydroxamic Acids and N‐Hydroxyimides

Bauer

Exner

1974

Angew. Chem. Int. Ed. Engl.

311

164

View full text Add to dashboard Cite

show abstract

“…2,50,51 The extent and accuracy of our exchange data do not allow tests of more sophisticated models including dimerization and/or conformational changes. 52 -54 Our experiments and calculations may also contribute to the long-debated problem of hydroxamic acid protonation and subsequent hydrolysis.…”

Section: Exchangementioning

confidence: 99%

Ring‐substituted benzohydroxamic acids: ¹H, ¹³C and ¹⁵N NMR spectra and NHOH proton exchange

Schraml

Tkadlecová

Pataridis

et al. 2005

Magnetic Reson in Chemistry

View full text Add to dashboard Cite

NMR spectra (1H, 13C, 15N) of para- and meta-substituted benzohydroxamic acids were studied in dry dimethyl sulfoxide solutions. The 13C chemical shifts were very close to those found by cross-polarization magic angle spinning in solids, the hydroxamic (not hydroximic) structure of which is unambiguous. The hydroxamic structure of these acids in DMSO solutions was proved independently by their 15N chemical shifts. The 15N and 1H chemical shifts of the NH-OH fragment showed excellent mutual dependences and dependences on the nature of the ring substituent. According to these dependences and ab initio energy calculations, all the acids assume the same Z conformation. Proton exchange between hydroxamic OH and NH groups in DMSO proceeded by both intra- and intermolecular exchange and the rates did not exhibit any simple relationship to the substituent constants.

show abstract

Acyl derivatives of hydroxylamine. XII. Dissociation constants of hydroxamic acids and their functional derivatives

Cited by 48 publications

References 0 publications

Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

The Chemistry of Hydroxamic Acids and N‐Hydroxyimides

Ring‐substituted benzohydroxamic acids: ¹H, ¹³C and ¹⁵N NMR spectra and NHOH proton exchange

Contact Info

Product

Resources

About

Acyl derivatives of hydroxylamine. XII. Dissociation constants of hydroxamic acids and their functional derivatives

Cited by 48 publications

References 0 publications

Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

Reactivity patterns of N-methylbenzhydroxamates. I. Studies of methyl transfer between N-methylbenzhydroxamates and arenesulfonates

The Chemistry of Hydroxamic Acids and N‐Hydroxyimides

Ring‐substituted benzohydroxamic acids: 1H, 13C and 15N NMR spectra and NHOH proton exchange

Contact Info

Product

Resources

About

Ring‐substituted benzohydroxamic acids: ¹H, ¹³C and ¹⁵N NMR spectra and NHOH proton exchange