Synthesis and spectroscopic characterisation of novel bioactive molecule of 3-(2-substituted)-1H-indol-3-yl)-1-(thiophen-2yl)prop-2-en-1-one chalcone derivatives as effective anti-oxidant and anti-microbial agents

Synthesis and antioxidant properties of 2-(3-(hydroxyimino)methyl)-1H-indol-1-yl)acetamide derivatives

Background

The main aim of this work was to synthesise a novel N-(substituted phenyl)-2-(3-(hydroxyimino) methyl)-1H-indol-1-yl) acetamide derivatives and evaluate their antioxidant activity. These compounds were prepared by a condensation reaction between 1H-indole carbaldehyde oxime and 2-chloro acetamide derivatives. The newly synthesised compound structures were characterised by FT-IR, 1H-NMR, mass spectroscopy and elemental analysis. Furthermore, the above-mentioned compounds were screened for antioxidant activity by using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods.

Result

The antioxidant activity result reveals that most of the compounds were exhibiting considerable activity in both methods and the values are very closer to the standards. Among the synthesised compounds, compound 3j, 3a and 3k were shown remarkable activity at low concentration.

Conclusion

Compounds 3j, 3a and 3k were shown highest activity among the prepared analogues due to the attachment of halogens connected at the appropriate place in the phenyl ring. Hence, these substituted phenyl rings considered as a perfect side chain for the indole nucleus for the development of the new antioxidant agents.

Ferrocenyl chalcone derivatives as possible antimicrobial agents

The swift spread of infections caused by drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), has quickly become a worldwide concern as infections spread from healthcare settings to the wider community. While ferrocenyl chalcones, which are chalcone derivatives with antimicrobial activity, have gained attention from researchers, further study is needed to assess their cytotoxicity. Ten newly developed chalcones, in which ring A was replaced with a ferrocenyl moiety and ring B contained increasing alkyl chain lengths from 1 to 10 carbons, were assessed. Using twofold broth microdilution, the minimum inhibitory concentration (MIC) of five of the ten compounds were lower against Gram-positive organisms (MICs from 0.008 mg ml^-1 to 0.063 mg ml^-1) than Gram-negative organisms (MICs = 0.125 mg ml^-1). These novel ferrocenyl chalcone compounds were effective against three types of clinically isolated drug-resistant S. aureus, including an MRSA, and against other non-resistant clinically isolated and laboratory-adapted Gram-positive bacteria. The same compounds inhibited growth in non-resistant bacteria by potentially obstructing cellular respiration in Gram-positive bacteria. Images obtained through scanning electron microscopy revealed fully lysed bacterial cells once exposed to a selected compound that showed activity. The results indicate that these newly developed compounds could be important antimicrobial agents in the treatment of infections from clinically resistant bacteria.

Third-order nonlinear optical properties of three chlorinated thienyl chalcones derivatives: synthesis, structural determination and Hirshfeld surface analysis

Three chlorinated theinyl chalcone derivatives, namely (E)-1-(5-chlorothiophen-2-yl)-3-(4-(methylthio)phenyl)prop-2-en-1-one (I), (E)-1-(5-chlorothiophen-2-yl)-3-(4-(dimethylamino)phenyl)prop-2-en-1-one (II) and (E)-1-(5-chlorothiophen-2-yl)-3-(2,3-dihydrobenzofuran-5-yl)prop-2-en-1-one (III), were synthesized and their crystal structures were determined by single-crystal X-ray diffraction analysis. Compounds I, II and III crystallize in the monoclinic space groups P 21/c (centrosymmetric), P 21/n (centrosymmetric) and Pc (non-centrosymmetric), respectively. In all three compounds, the molecules are in a relatively planar conformation and adopt a trans configuration with respect to the C=C double bond. The crystal packings are stabilized by weak hydrogen-bonds, π · · · π, C–H · · · π and C–Cl · · · π interactions. The intermolecular contacts and lattice energies were further analyzed by Hirshfeld surface analysis. The third-order nonlinear optical properties of these chalcone derivatives were investigated using the single beam Z-scan technique with a 5 mW continuous wave diode laser operating at 635 nm, where compound I showed the highest potential for optical application with its exclusive nonlinear refractive index and nonlinear susceptibility.