Brahim Cherfaoui

In this contribution, we report the study of nuclear resonance magnetic spectroscopy techniques (¹H-NMR, ¹³C-NMR, and 2D-NMR) efficiency in the characterisation of the functional composition of water-soluble organic compounds (WSOC) from atmospheric aerosols. The chosen site was our scientific and technical center of research (CRAPC) situated in Algerian Bou-Ismail city. where the concentrations of PM₁₀ were found to be between 15.66 and 142.19 µg.m⁻³. As results, ¹H-NMR analysis showed the coexistence of biological material and emissions from urban and biomass burning. The dominant source was identified by quantitative integration of each 1H NMR spectral region. By using the HSQC technique, many peaks are revealed in biogenic samples including biomass burning. On the other hand, the identification of the source of various organic compounds and their functional composition is possible through specific NMR spectra, which can also be used to adjust the surrounding organic aerosol sources.

An efficient in situ condensation of citronellal, the main constituent of Eucalyptus citriodora essential oil (51%), with different amine derivatives of 2,3-diaminomaleonitrile and 3-[(2-aminoaryl)amino]dimedone has led to novel chiral benzodiazepine structures. All reactions were precipitated in ethanol and pure products were obtained in good yields (58–75%) without any purification. The synthesized benezodiazepines were characterized by spectroscopic techniques, namely ¹H-NMR, ¹³C-NMR, 2D NMR and FTIR. Differential Scanning Calorimetry (DSC) and HPLC were used to confirm the formation diastereomeric mixtures of benzodiazepine derivatives. Graphical Abstract

Background: Recently, the essential oil (EO) of Ammodaucus leucotrichus has attracted particular attention in hemi-synthesis due to the reactivity of its main monoterpenes.Objective: In vitro cytotoxic and antileishmanial activities of the EO and hemi-synthesized compounds were evaluated, and an in-silico simulation was conducted.Methods: The EO was characterized by GC-MS. Two benzodiazepines (C1, C2), benzimidazole (C3), and Schiff base (C4) were hemi-synthesized by an in situ condensation of its major monoterpenes (perillaldehyde) with different amine derivatives. Synthesized compounds and the EO were evaluated for their cytotoxic activity against laryngeal carcinoma-Hep2 and rhabdomyosarcoma-RD cell lines and for their antileishmanial activity against Leishmania (L) major. Molecular docking was performed to pin the binding interactions of active molecules.Results: A significant cytotoxic effect of benzodiazepines C1 and C2 was noted against Hep2 cells (IC50/C1 = 39.48 ±0.7 μM, IC50/C2 = 48.82±1.33 μM) and RD (IC50/C1 = 15.96±1.99 μM; IC50/C2 = 74.3±2.44 μM), while the EO highly inhibited Hep2 cell lines (IC50/EO = 17.3±0.85 μg/mL). C4 strongly inhibited L. major growth with an IC50 value of 8.00±1.37 Μμ. The docking scores of ligand-C4 on L. major pteridine reductase and L. major methionyl-tRNA synthetase and ligands-(C1, C2) on the human protein kinase and epidermal growth factor kinase presented significant affinity to the receptor active sites (ΔG from -7.7 to -8.8 kcal/mol).Conclusion: The cytotoxic effect of derivatives C1, C2, and EO, as well as the anti-parasitic effect of C4, may suggest them as effective bioactive agents or pharmaceutical probes.

The hemi-synthesis of chiral imine, benzimidazole and benzodiazepine structures is reported by the condensation of (S)-(−)-perillaldehyde, the major phytochemical of Ammodaucus leucotrichus subsp. leucotrichus essential oil, with different amine derivatives of 2,3-diaminomaleonitrile, o-phenylenediamine and 3-[(2-aminoaryl)amino]dimedone. The reaction proceeds in situ at ambient temperature without prior isolation of the natural (S)-(−)-perillaldehyde. Final products precipitate in the ethanolic reaction medium. 2D NMR and single-crystal X-ray diffraction studies were used to unequivocally characterize the structures in solution and in the solid state, respectively. Chiral HPLC analysis confirms the formation of unique enantiomers and diastereomeric mixtures.