Effects of the Nitrone Group in NMR Spectra of α,N-Diphenylnitrones
Kinko Koyano,Hiroshi Suzuki +1 more
TLDR
In this paper, the NMR and UV spectra of α,N-diphenylnitrone and its derivatives were measured and the effect of the electron-donating power of the para substituent was investigated.Abstract:
The NMR and UV spectra of α,N-diphenylnitrone and its derivatives which have a substituent at the para position of the α-phenyl group and some of which have in addition a methyl substituent at the ortho position of the α-phenyl group were measured. Examination led to the following conclusions. The NMR signal of the ortho protons of the α-phenyl group appears at a very low field. This is mainly attributed to the direct effect of the negatively charged oxygen atom of the nitrone group. Increase in the electron-donating power of the para substituent enhances this effect.read more
Citations
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Dramatic solvents effects on the enantioselectivity of chiral oxazaborolidine catalyzed asymmetric 1,3-dipolar cycloadditions of nitrones with ketene acetals☆
TL;DR: The enantioselectivity of the chiral oxazaborolidine catalyzed asymmetric 1,3-dipolar cycloaddition of nitrones with 1,1-dialkoxypropenes can be controlled by the α-side-chain substituent in the catalyst and the solvent as discussed by the authors.
Journal ArticleDOI
Ring-Ketten-Isomerie bei N-(2-Hydroxyalkyl)nitronen, I Substituierte Benzaldehyd-nitrone
Wolfgang Kliegel,Harald Becker +1 more
TL;DR: The ring-chain transformation of N-(2-hydroxyalkyl)nitrones, obtained from substituted benzaldehydes, is studied by reactions forming the B,N-betaine type boron chelates 16 from the open-chain nitrone form, the acyl derivatives 21 and 23 from both isomers, and the oxidation products from the cyclic N-hydroxoxazolidine form 10.
Journal ArticleDOI
Electronic effects in 1,3-dipolar cycloaddition reactions of N-alkyl and N-benzyl nitrones with dipolarophiles
Andrei Badoiu,E. Peter Kündig +1 more
TL;DR: Using a chiral one-point binding ruthenium Lewis acid catalyst, 1,3-Dipolar cycloadditions afforded fast access to isoxazolidines bearing N-alkyl or N-benzyl substituents and obtained good yields and with excellent regio-, diastereo-, and enantioselectivity.
Journal ArticleDOI
Investigation of substituent effects on the 1H and 13C NMR spectra of (Z)‐N‐(arylmethylene)‐arylamine N‐oxides (α,N‐diaryl nitrones)
TL;DR: In this article, a correlation has been found between the chemical shifts of the azomethine proton (H-α) and the Hammett σ parameters and the Swain and Lupton F and R parameters.
References
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Absorption Spectra of Azo- and Related Compounds. II.1 Substituted Phenylnitrones
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Janet S. Splitter,Melvin Calvin +1 more
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High resolution proton magnetic resonance studies of para-disubstituted benzenes
TL;DR: In this paper, the results of high resolution proton nmr experiments on compounds of the type where X and Y are arbitrary substituents are analyzed in terms of the additivity theory of Diehl, and the correlation of the substituent effects with the Hammett parameter and with the group electric dipole moments is examined.
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The Electronic Spectra of Nitrones and the Solvent Effect on Them
TL;DR: The ultraviolet spectra of nitrones, the configurations of which were assumed from their dipole moments and chemical reactivities, and their related compounds have been measured in various solvents as mentioned in this paper.