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Balzarini, Jan; Stevens, Miguel; Andrei, Gracíela; Snoeck, Robert; Strunk, Richard G.; Pierce, J. B.; Lacadie, John A.; Clercq, Erik De; Pannecouque, Christophe

doi:10.1002/1522-2675(200209)85:9<2961::aid-hlca2961>3.0.co;2-r

Cited by 28 publications

(10 citation statements)

References 2 publications

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“…We probed the interaction of the tetraester 3 a with pyridyl N ‐oxides by 1 H NMR spectroscopy. Pyridine N ‐oxides have relevant biological activity . They are known to act as a novel class of antiviral drugs by inhibiting the replication processes.…”

Section: Resultsmentioning

confidence: 99%

Super Aryl‐Extended Calix[4]pyrroles: Synthesis, Binding Studies, and Attempts To Gain Water Solubility

Escobar

Aragay

Ballester

2016

Chemistry A European J

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We describe the synthesis of unprecedented calix[4]pyrrole receptors featuring "super aryl extended" (SAE) cavities. We elaborated the aromatic cavity provided by the αααα-isomer of para-tetraiodo-meso-phenyl calix[4]pyrrole by installing ethynyl-aryl substituents at its upper rim. We report the binding properties of the prepared SAE-calix[4]pyrrole tetraester towards pyridyl-N-oxides. The binding data revealed the formation of thermodynamically and kinetically highly stable 1:1 complexes. The complexation-induced chemical shifts indicated the formation of hydrogen bonds and aromatic interactions with the calix-core adopting the cone conformation. We quantified the additional interactions established between the four terminal aryl groups and the para-phenyl substituent of 4-phenyl pyridine N-oxide to be in the order of 1 kcal mol(-1) . The complex formation rate was found to be close to the diffusion control suggesting that the free host adopted a 1,3-alternate conformation. Finally, we attempted to gain water solubility of SAE-calix[4]pyrroles using derivatives that display four ionizable or charged groups at their upper rims.

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Section: Resultsmentioning

confidence: 99%

Super Aryl‐Extended Calix[4]pyrroles: Synthesis, Binding Studies, and Attempts To Gain Water Solubility

Escobar

Aragay

Ballester

2016

Chemistry A European J

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“…In the literature we can find the evidence of bactericidal, analgesic, anticonvulsant, apoptotic, and antimicrobial activity of N-oxides [2,3]. These properties allow to use N-oxides as inhibitor of HIV-1 reverse transcriptase [4,5], as antiviral agent against various SARS corona virus strains [6], and as antiadhesive and quorum-sensitive inhibitor [7]. Some complexes with pyridine-N-oxides are used in agriculture to regulate plant growth rates [8].…”

Section: Introductionmentioning

confidence: 99%

Molecular structure and electron distribution of 4-nitropyridine N-oxide: Experimental and theoretical study of substituent effects

Belova

Pimenov

Kotova

et al. 2020

Journal of Molecular Structure

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The molecular structure of 4-nitropyridine N-oxide, 4-NO 2 -PyO, has been determined by gas-phase electron diffraction monitored by mass spectrometry (GED/MS) and by quantum chemical calculations (DFT and MP2). Comparison of these results with those for non-substituted pyridine N-oxide and 4methylpyridine N-oxide CH 3 -PyO, demonstrate strong substitution effects on structural parameters and electron density distribution. The presence of the electron-withdrawing eNO 2 group in para-position of 4-NO 2 -PyO results in an increase of the ipso-angle and a decrease of the semipolar bond length r(N/O) in comparison to the non-substituted PyO. The presence of the electron-donating eCH 3 group in 4-CH 3 -PyO leads to opposite structural changes. Electron density distribution in pyridine-N-oxide and its two substituted compounds are discussed in terms of natural bond orbitals (NBO) and quantum theory atoms in molecule (QTAIM).

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“…Nitropyridine-N-oxide derivatives have received particular interest in chemistry and biotechnology due to their accentuated oxidizing properties, high polarity, and their versatility as simultaneous charge donors and acceptors. These properties have qualified these compounds to be widely used in various fields of applications, e.g., as organocatalysts for asymmetric allylation of aldehydes [1], as inhibitor of HIV-1 reverse transcriptase [2,3], as antiviral agent against various SARS coronavirus strains [4], as antiadhesive and quorum-sensing inhibitor, and as antifungal agent [5]. Recent studies have shown that pyridine-N-oxide derivatives are genotoxic.…”

Section: Introductionmentioning

confidence: 99%

A theoretical investigation of the structure of 2-nitropyridine-N-oxide and the dependency of the NO2 torsional motion on the applied wavefunction and basis set

Dakkouri

Typke

2013

Struct Chem

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HF, B3LYP, and MP2 wave functions in combination with Pople 6-31, 6-311 augmented with polarization functions on all atoms and Dunning doubleand triple-zeta basis sets have been employed to investigate the structures and torsional potential function of the nitro group in 2-nitropyridine-N-oxide (2-NPO) and a variety of its fluorinated derivatives. The augmentation of the basis sets with diffuse functions showed a marked effect on the profile and barriers of the NO 2 torsional potential. Depending on the applied model chemistry, the heterocyclic ring in some 2-NPOs has proved to be non-planar. The non-planarity of the ring was characterized by Cremer-Pople puckering amplitude Q. The disruption of the ring planarity in some NPOs was accounted for the distinctive reactivity and impact sensitivity of these heterocycles. Consistently, the NBO and the AIM analyses furnished clear evidence for the accentuated weakness of the C-NO 2 bond and provided evidence for the electronic interplay between the NO 2 group, the fluorine substituent and the heterocyclic ring. Deletion of all off-diagonal Fock-matrix elements (NOSTAR) to separate hyperconjugative stabilizing interactions from steric interactions was used. The effect of nitration and fluorination on the aromaticity of the studied 2-NPOs was investigated by using the NICS descriptors NICS(1) and NICS(1) zz . These NICS indices have shown that the fluorination in para position to the nitro group exhibits the highest degree of aromaticity within the fluorinated 2-NPOs.Keywords 2-Nitropyridine-N-oxide Á Fluoro-2nitropyridine-N-oxide Á NO 2 torsional potential Á C-NO 2 bond Á Ring non-planarity Á NBO Á AIM Á NOSTAR deletion Á NICS(1) zz Electronic supplementary material The online version of this article (

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Cited by 28 publications

References 2 publications

Super Aryl‐Extended Calix[4]pyrroles: Synthesis, Binding Studies, and Attempts To Gain Water Solubility

Super Aryl‐Extended Calix[4]pyrroles: Synthesis, Binding Studies, and Attempts To Gain Water Solubility

Molecular structure and electron distribution of 4-nitropyridine N-oxide: Experimental and theoretical study of substituent effects

A theoretical investigation of the structure of 2-nitropyridine-N-oxide and the dependency of the NO2 torsional motion on the applied wavefunction and basis set

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