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Chalcones are important intermediates in the biosynthesis of biologically active compounds such as flavonoids and their derivatives. In this paper, a new chalcone 2E-1-(2ʹ-Hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-(phenyl)-prop-2-en-1-one (HYTPHENYL) was synthesized by the condensation reaction of Claisen-Schmidt in basic medium between the 2-hydroxy-3,4,6-trimethoxyacetophenone (HTMCX) and benzaldehyde. The molecular structure of this chalcone was determined by Nuclear Magnetic Resonance, and characterized by infrared and Raman spectroscopy, at room temperature. Its electrochemical behavior was also evaluated. Vibrational wavenumber and wavevector have been predicted using the Density Functional Theory (DFT) calculations and their normal modes were analyzed in terms of the potential energy distribution (PED). Furthermore, DFT calculations were carried out to obtain the molecular orbitals and the electrostatic surface map. Electronic absorption spectrum of HYTPHENYL was measured and compared with that obtained for the HTMCX compound. Additionally, analysis of the antimicrobial activity and antibiotic resistance modulation was carried out to evaluate the antibacterial potential of the HYTPHENYL chalcone.

Background: Chalcones are part of a family of small phenolic compounds that are being extensively studied for presenting a diversity of molecular structures and biological activities. In this paper, two chalcones, (E)-1-(2-hydroxy-3,4,6-trimethoxyphenyl)-3-(3-nitrophenyl)prop-2-en-1-one (1), (E)-1-(2-hydroxy-3,4,6-trimethoxyphenyl)-3-(4-nitrophenyl)prop-2-en-1-one (2), were synthesized by Claisen&ndash, Schmidt condensation. Methods: The molecular structures of these chalcones were determined by Nuclear Magnetic Resonance and characterized by infrared, Raman spectroscopy, and electrochemical analysis at room temperature. Vibrational wavenumbers were predicted using Functional Density Theory (DFT) calculations, and their normal modes were analyzed in terms of potential energy distribution (PED). Besides this, DFT calculations were performed to obtain the molecular orbitals and their quantum descriptors. The UV-Vis absorption spectrum of the synthesized chalcones was measured and compared with each other. In addition, analyses of antimicrobial activity and modulation of antibiotic resistance were carried out to assess the antibacterial potential of these chalcones. Results: The vibrational spectra of polycrystalline chalcones obtained by ATR-FTIR , FT-Raman and DFT calculations allowed a complete assignment of the vibrational modes, and revealed the quantum chemical parameters. Both chalcones did not show good responses when associated with the antibiotics Ciprofloxacin and Cephalexin against S. aureus 10 and E. coli 06 strains. However, a significant potentiating of the Gentamicin activity against S. aureus 10 and E. col 06 strains was observed for chalcone 2. On the other hand, when associated with Norfloxacin, an antagonistic effect was observed. The results found for EtBr suggest that, although the tested chalcones behave as efflux pump inhibitors, probably inhibiting other efflux pumps, they were not able to inhibit NorA. Thus, these synthetic chalcones are not recommended for use in association with Norfloxacin against strains of S. aureus 1199-B that overexpress the NorA gene. Conclusions: Spectroscopic data confirmed the structure of the chalcones, and chalcone 2 showed potential as an adjuvant in antibiotic therapy.

This work describes the electroanalytical determination of Chlorpyriphos pesticide in natural waters using hanging mercury drop electrode allied to square wave adsorptive cathodic stripping voltammetry. The best responses were obtained in Britton‒Robinson buffer solutions at pH 2.0, using a frequency of 100 s–1, a scan increment of 5 mV, a square wave amplitude of 25 mV and an accumulation potential of–0.4 V during 60 s. Therefore, voltammetric responses showed the presence of one well-defined and irreversible reduction peak, at–1.08 V vs. Ag/AgCl/KCl 1.0 M, which involves two electrons in the reduction of carbon‒nitrogen bond in the N-heterocyclic system with the participation of protonation equilibrium preceding the electron transfer reaction. Analytical curves were constructed and compared to similar curves performed by gas chromatograph coupled to a selective nitrogen‒phosphorus detector, which demonstrates that the proposed methodology is suitable for determining contamination by Chlorpyriphos in complex samples.

Chalcones and their derivatives exhibit a broad spectrum of pharmacological activities, including antiproliferative activities. Accordingly, they are deemed robust anticancer candidates for cytotoxicity assays. Herein, we synthesized and characterized four chalcones using nuclear magnetic resonance (1H NMR and 13C NMR), Fourier transform Raman (FT-Raman), attenuated total reflection Fourier transform infrared (ATR-FTIR), and ultraviolet-visible (UV–vis) spectroscopy. Theoretical calculations of quantum chemistry were performed to obtain data regarding normal vibration modes, frontier molecular orbitals, molecular electrostatic potential maps, theoretical UV–vis spectra, and quantum chemical parameters expected for these chalcones. In addition, we evaluated the cytotoxic potential of these compounds. For synthesized compounds, quantum chemical calculations demonstrated excellent correlation with experimental data. The electronic properties revealed that chalcones 1 and 4 possess a higher electrophilic character, while chalcones 2 and 3 possess a higher nucleophilic character. Chalcone 3 demonstrated the highest value of HOMO energy, indicating the greatest propensity to donate electronic density among the four compounds. According to the HOMO-LUMO energy gap and global hardness, the reactivity of chalcones should follow the order 1

In the present study, the chalcone (2E)-1-(3′-methoxy-4′-hydroxyphenyl)-3-(3-nitrophenyl)prop-2-en-1-one (C16H13NO5, hereafter named AVMNB) was synthesized and structurally characterized using the 1H and 13C NMR technique and GC-MS. The vibrational and electrochemical properties of the AVMNB chalcone and its antibacterial activity against multi-resistant strains of Escherichia coli 06 and Staphylococcus aureus 10 were evaluated. The FT-Raman, ATR-FTIR, and UV-VIS spectra of the polycrystalline samples were recorded at room temperature. Quantum chemistry theoretical calculations were used to obtain information about the normal vibration modes, and the electronic transitions and the quantum chemical parameters expected for this chalcone. The pharmacokinetics properties were also estimated using the SwissADME platform. The AVMNB chalcone displayed antibacterial activity against multi-resistant strains of Staphylococcus aureus 10 and Escherichia coli 06 when associated with the ciprofloxacin and gentamicin antibiotics, respectively, indicating that this compound may contribute to the control of antibacterial resistance.