Development of novel isatin thiazolyl-pyrazoline hybrids as promising antimicrobials in MDR pathogens

Microbial Multidrug Resistance (MDR) is an emerging global crisis. Derivatization of natural or synthetic scaffolds is among the most reliable strategies to search for and obtain novel antimicrobial agents for the treatment of MDR infections. Here, we successfully manipulated the synthetically flexible isatin moieties to synthesize 22 thiazolyl-pyrazolines hybrids, and assessed their potential antimicrobial activities in vitro against various MDR pathogens, using the broth microdilution calorimetric XTT reduction method. We chose 5 strains to represent the major MDR microorganisms, viz: Methicillin resistant S. aureus (MRSA), and Vancomycin-resistant E. faecalis (VRE) as Gram-positive bacteria; Carbapenem-resistant K. pneumonia (CRKP), and Extended-spectrum beta-lactamase E. coli (ESBL-E), as Gram-negative bacteria; and Fluconazole-resistant C. albicans (FRCA), as a yeast-like unicellular fungus.The cytotoxicity of compounds 9f and 10h towards mammalian lung fibroblast (MRC-5) cells demonstrated their potential satisfactory safety margin as represented by their relatively high IC50 values. The target compounds showed promising anti-MDR activities, suggesting they are potential leads for further development and in vivo studies

Unexpected Synthesis, Single-Crystal X-ray Structure, Anticancer Activity, and Molecular Docking Studies of Certain 2–((Imidazole/Benzimidazol–2–yl)thio)–1–arylethanones

In connection with our research program concerning development of novel effective benzimidazole-based anticancer candidates, herein we describe a new unexpected synthetic route to obtain a series of 2–((imidazole/benzimidazol2–yl)thio)1–arylethanones endowed with promising anti-breast cancer and Cyclin-dependent kinase 2 (CDK2) inhibitory activities. Contrary to expectations, products for the reaction of 2–mercaptoimidazole/benzimidazole 2a,b with β–keto esters 6a–c were unambiguously assigned as 2–((imidazol/benzimidazol2–yl)thio)1–arylethanones 10a–f based on NMR spectroscopy and single-crystal X-ray crystallographic analyses. In vitro anticancer activities for herein reported imidazole/benzimidazoles 10a–f were assessed through a cell-based assay against human breast cancer T4–7D and MCF–7 cell lines. Benzimidazoles 10d–f exerted better anti-proliferative action towards T4–7D and MCF–7 cell lines than their corresponding imidazole counterparts 10a–c. Furthermore, a molecular docking study suggested CDK2 kinase as a potential enzymatic target for benzimidazoles 10d–f, and investigated their possible binding pattern and interactions within CDK2 active site. Thereafter, benzimidazoles 10d–f were in vitro examined for their CDK2 inhibitory action, where they exerted good activity. Finally, several key ADME and druglikeness properties were predicted by the SwissADME online tool. Interestingly, benzimidazoles 10d–f were found to have no violations in all druglikeness rules (Veber, Lipinski, Ghose, Muegge, and Egan). In addition, they had neither PAINS nor structural alerts (Brenks). In conclusion, benzimidazoles 10d–f demonstrated not only a promising anticancer activities but also an acceptable ADME and physicochemical properties especially benzimidazole 10e

Synthesis of 2-(4,6-Dimethoxy-1,3,5-triazin-2-yloxyimino) Derivatives: Application in Solution Peptide Synthesis

A new class of 1,3,5-triazinyloxyimino derivatives were prepared, characterized and tested for reactivity in solution peptide synthesis. The new triazinyloxyimino derivatives failed to activate the carboxyl group during formation of peptide bonds, but gave the corresponding N-triazinyl amino acid derivatives as a major product. The oxyma (ethyl 2-cyano-2-(hydroxyimino)acetate) uronium salt was superior to other uronium salts in terms of racemization, while 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT, 9) gave the best results

New Platinum(IV) and Palladium(II) Transition Metal Complexes of s-Triazine Derivative: Synthesis, Spectral, and Anticancer Agents Studies

New Pd(II) and Pt(IV) triazine complexes [Pt3(L1)2(Cl)9(H2O)3].3Cl.3H2O (1), [Pt3(L2)2(Cl)9(H2O)3].3Cl (2), [Pt3(L3)2(Cl)9(H2O)3].3Cl (3), [Pt2(L4)2(Cl)6(H2O)2] .2Cl.4H2O (4), [Pd3(L1)2(H2O)6] .3Cl2 (5), [Pd3(L2)2(H2O)6].3Cl2 (6), [Pd3(L3)2(H2O)6].3Cl2 (7), and [Pd2(L4)2(H2O)4].2Cl2 (8) were synthesized and well characterized using elemental analyses, molar conductance, IR, UV-Vis, magnetic susceptibility, 1H, 13C-NMR spectra, and thermal analyses. These analyses deduced that the L1, L2, and L3 ligands act as tridentate forming octahedral geometry with Pt(IV) metal ions and square planar geometry in case of Pd(II) complexes but the L4 ligand acts as bidentate chelate. The molar conductance values refer to the fact that all the prepared s-triazine complexes have electrolyte properties which are investigated in DMSO solvent. Surface morphology behaviors of prepared complexes have been scanned using TEM. The crystalline behavior of triazine complexes has been checked based on X-ray powder diffraction patterns. The antimicrobial activity of the free ligands and their platinum(IV) and palladium(II) complexes against the species Staphylococcus aureus (G+), Escherichia coli (G−), Aspergillus flavus, and Candida albicans has been carried out and compared with the standard one. The coordination of ligands towards metal ions makes them stronger bacteriostatic agents, thus inhibiting the growth of bacteria and fungi more than the free ligands. The cytotoxic assessment IC50 of the free ligands and its platinum(IV) complexes in vitro against human colon and lung cancer cell lines introduced a promising efficiency

Synthesis of 2-(4,6-Dimethoxy-1,3,5-triazin-2-yloxyimino) Derivatives: Application in Solution Peptide Synthesis

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Synthesis of 2-(4,6-dimethyoxy-1,3,5-triazin-2-yloxyimino) Derivatives: Application in Solution Peptide Synthesis

A new class of 1,3,5-triazinyloxyimino derivatives were prepared, characterized and tested for reactivity in solution peptide synthesis. The new triazinyloxyimino derivatives failed to activate the carboxyl group during formation of peptide bonds, but gave the corresponding N-triazinyl amino acid derivatives as a major product. The oxyma (ethyl 2-cyano-2-(hydroxyimino)acetate) uronium salt was superior to other uronium salts in terms of racemization, while 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT, 9) gave the best results

Antibacterial, Antioxidant Activity of Ethanolic Plant Extracts of Some Convolvulus

Convolvulus austroaegyptiacus Abdallah & Sa’ad (CA) and Convolvulus pilosellifolius Desr. (CP) are commonly used in the Saudi Arabia folk medicine. They are potent in treating the ulcers and skin diseases. The lack of information about their biological activities led us to investigate the possible biological activities by determination of antibacterial and antioxidant activities of total ethanolic extracts and various fractions. Total flavonoid contents of the plants were determined by colorimetric method while total phenols were determined by using Folin-Ciocalteu method. In vitro antibacterial activity was studied against E. coli, P. aeruginosa, and B. subtilis, and the total antioxidant capacity was evaluated by radical scavenging method. IC50 were found to be 21.81, 17.62, and 3.31 μg/mL for CA, CP, and vitamin C, respectively, while the lowest MIC value of 0.25 mg/mL was recorded with CP extract against B. subtilis. Around 21 compounds are tentatively elucidated from both plants using rapid, simple, and high-resolution analytical technique for chemical profiling of natural compounds by direct analysis in real-time of flight-mass spectrometry, of which 17 were not isolated or reported previously

Metallic Porphyrazine Networks: Synthesis, as Well as Thermal and Optical Properties for Accelerating the Oxidation of Thiols to Their Disulfides

A condensation reaction of 2,3,5,6-tetraamino-1,4-benzoquinone 1 with 4,5-Dichloro-3,6-dihydroxy-phthalonitrile 2 produced p-benzoquinone [2,3-b:2,3-b]bis[(5,8-dihydroxybenzopyrazine)-6,7-dinitrile] 3. Utilizing acetic acid with lithium/pentanol, the tetra-nitrile monomer was cyclo-tetramerized, yielding the matching network polymer, tetra p-benzoquinone[2,3-b:2,3-b]. bis[(5,8-dihydroxybenzopyrazino) porphyrazine (2H-Pz) 4a. The equivalent tetra p-benzoquinone[2,3-b:2,3-b]bis[(5,8-dihydroxybenzopyrazino) metallic porphyrazine networks (M-Pz) M = Zn 4b or Ni 4c, were obtained by cyclo-tetramerizing the tetra-nitril monomer 3 using metal salt and quinoline. The synthesized molecules’ elemental analytical results, as well as their IR and NMR spectral data, are consistent with their assigned structures. The prepared compounds have large molecular weights and metal content, indicating that reactions of tetramerization, polymerization, and chelation were all productive. The synthesized porphyrazines were proved to be excellent substrates for oxidizing thiophenol and benzyl thiol to their respective disulfides in atmospheric oxygen. The maximal production of the corresponding disulfides after 15 min was 96 percent for thiophenol and 93 percent for benzyl thiol, respectively

Metallic Porphyrazine Networks: Synthesis, as Well as Thermal and Optical Properties for Accelerating the Oxidation of Thiols to Their Disulfides

A condensation reaction of 2,3,5,6-tetraamino-1,4-benzoquinone 1 with 4,5-Dichloro-3,6-dihydroxy-phthalonitrile 2 produced p-benzoquinone [2,3-b:2,3-b]bis[(5,8-dihydroxybenzopyrazine)-6,7-dinitrile] 3. Utilizing acetic acid with lithium/pentanol, the tetra-nitrile monomer was cyclo-tetramerized, yielding the matching network polymer, tetra p-benzoquinone[2,3-b:2,3-b]. bis[(5,8-dihydroxybenzopyrazino) porphyrazine (2H-Pz) 4a. The equivalent tetra p-benzoquinone[2,3-b:2,3-b]bis[(5,8-dihydroxybenzopyrazino) metallic porphyrazine networks (M-Pz) M = Zn 4b or Ni 4c, were obtained by cyclo-tetramerizing the tetra-nitril monomer 3 using metal salt and quinoline. The synthesized molecules’ elemental analytical results, as well as their IR and NMR spectral data, are consistent with their assigned structures. The prepared compounds have large molecular weights and metal content, indicating that reactions of tetramerization, polymerization, and chelation were all productive. The synthesized porphyrazines were proved to be excellent substrates for oxidizing thiophenol and benzyl thiol to their respective disulfides in atmospheric oxygen. The maximal production of the corresponding disulfides after 15 min was 96 percent for thiophenol and 93 percent for benzyl thiol, respectively