Proton and carbon nuclear magnetic resonance study on some n- and o-acyl derivatives of monohydroxypyridines

Giudice, Maria Rosaria Del; Settimj, Guido; Delfini, Maurizio

doi:10.1016/0040-4020(84)85087-5

Cited by 29 publications

(12 citation statements)

References 27 publications

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“…[22] Consequently, it was not surprising that reaction of 4-pyridone with 4-pentynoyl chloride led to an inseparable 2:3 mixture of the N-and O-acylated derivatives 13 and 14, respectively (Scheme 2). [23] The alkynylation of pyrazinones was achieved in a manner similar to that described for the pyridone systems (Table 4). Precursors for all-intramolecular cyclizations were obtained by double alkynylation of pyrazinediones (Table 5).…”

Section: Resultsmentioning

confidence: 99%

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Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Aubert

Betschmann

Eichberg

et al. 2007

Chemistry A European J

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The reactivity of a range of pyridone and pyrazinone derivatives towards alkynes in the presence of cyclopentadienylcobaltbis(ethene) has been investigated. Depending on the nature of the substrates, [2+2+2]- or [2+2] cycloaddition, C-H, or N-H activation may occur. In the case of pyridones, the first three predominated with N-protected derivatives, whereas substrates containing N-H bonds followed an N-H activation pathway. The [2+2+2] cycloaddition of an N-butynylisoquinolone was applied successfully to the total synthesis of anhydrolycorinone. Pyrazinone substrates showed similar patterns of reactivity.

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Section: Resultsmentioning

confidence: 99%

“…[4, 6,12] Therefore, undaunted by the lability of N-acylpyridones and their propensity to equilibrate with their ester isomers, [21][22][23] 13 (admixed with 14) was exposed to BTMSA and [CpCoA C H T U N G T R E N N U N G (C 2 H 4 ) 2 ] (Scheme 10).…”

mentioning

confidence: 99%

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Aubert

Betschmann

Eichberg

et al. 2007

Chemistry A European J

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“…1. The 3,4-substitution pattern was supported by FT-IR spectroscopy, as a double band between 1770 and 1760 cm -1 corresponding to reported carbonyl stretching vibrations of similar quinolone-derived di-esters [28] was observed in the spectrum but no band at around 1650 cm -1 excluding the N-acetylated product [29] This study illustrates that chemical derivatization is a powerful tool also in LC-MS analysis as already applied e.g. in pharmacokinetics [30] to improve detection specificity, ionization efficiency, sensitivity and chromatographic behavior of analytes.…”

Section: Sample Processingmentioning

confidence: 81%

Development and validation of a UHPLC–MS/MS procedure for quantification of the Pseudomonas Quinolone Signal in bacterial culture after acetylation for characterization of new quorum sensing inhibitors

Maurer

Steinbach

Hartmann

2013

Journal of Pharmaceutical and Biomedical Analysis

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The appearance of antibiotic resistance requires novel therapeutic strategies. One approach is to selectively attenuate bacterial pathogenicity by interfering with bacterial cell-to-cell communication known as quorum sensing. The PQS quorum sensing system of Pseudomonas aeruginosa employs as signal molecule the Pseudomonas Quinolone Signal (PQS; 2-heptyl-3-hydroxy-4-(1H)-quinolone), a key contributor to virulence and biofilm formation. Thus, interference with PQS production is considered as promising approach for the development of novel anti-infectives. Therefore, in this study, we developed and validated an ultra-high performance liquid chromatographic-tandem mass spectrometric approach for reliable quantification of PQS in P. aeruginosa cultures for activity determination of new quorum sensing inhibitors. The poor chromatographic properties of PQS reported by others could be overcome by fast microwave-assisted acetylation. The validation procedure including matrix effects, recovery, process efficiency, selectivity, carry-over, accuracy and precision, stability of the processed sample, and limit of quantification demonstrated that the method fulfilled all requirements of common validation guidelines. Its applicability was successfully proven in routine testing. In addition, two-point calibration was shown to be applicable for fast and reliable PQS quantification saving time and resources. In summary, the described method provides a powerful tool for the discovery of new quorum sensing inhibitors as potential anti-infectives and illustrated the usefulness of chemical derivatization, acetylation, in liquid chromatography-mass spectrometry analysis.

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“…It is well known that the electronegative atom reduces the electron density of carbon atom, so its 13 C NMR peak shifts to downfield region in the NMR spectrum. Such effects of chemical shifts [37] are very well known in the literature [38]. The carbon atoms C2, C4 and C6 were calculated in the down field due to the deshielding effect of N and Cl atoms.…”

Section: Nmr Spectra Analysismentioning

confidence: 99%

A theoretical study on 2-chloro-5-(2-hydroxyethyl)-4-methoxy-6-methylpyrimidine by DFT/ab initio calculations

Gümüş

Avcı

Atalay

et al. 2015

Materials Science-Poland

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Quantum chemical calculations have been performed to study the molecular geometry, 1 H and 13 C NMR chemical shifts, conformational, natural bond orbital (NBO) and nonlinear optical (NLO) properties of the 2-chloro-5-(2-hydroxyethyl)-4-methoxy-6-methylpyrimidine molecule in the ground state using DFT and HF methods with 6-311++G(d,p) basis set. The optimized geometric parameters and 1 H and 13 C NMR chemical shifts have been compared with the experimental values of the title molecule. The results of the calculations show excellent agreement between the experimental and calculated frequencies at B3LYP/6-311++G(d,p) level. In order to provide a full understanding of the properties of the title molecule in the context of molecular orbital picture, the highest occupied molecular energy level (E HOMO ), the lowest unoccupied molecular energy level (E LUMO ), the energy difference (∆E) between E HOMO and E LUMO , electronegativity (χ), hardness (η) and softness (S) have been calculated using B3LYP/6-311++G(d,p) and HF/6-311++G(d,p) levels. The calculated HOMO and LUMO energies show that the charge transfer occurs within the title molecule.

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Proton and carbon nuclear magnetic resonance study on some n- and o-acyl derivatives of monohydroxypyridines

Cited by 29 publications

References 27 publications

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Development and validation of a UHPLC–MS/MS procedure for quantification of the Pseudomonas Quinolone Signal in bacterial culture after acetylation for characterization of new quorum sensing inhibitors

A theoretical study on 2-chloro-5-(2-hydroxyethyl)-4-methoxy-6-methylpyrimidine by DFT/ab initio calculations

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