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    Bioactive NHC-derived palladium complexes: synthesis, catalytic activity for the Suzuki-Miyaura coupling of aryl chlorides and bromides and their antibacterial activities
    (Taylor & Francis Ltd, 2019) Boubakri, Lamia; Al-Ayed, Abdullah S.; Mansour, L.; Abutaha, Nael; Harrath, Abdel Halim; Ozdemir, I; Yasar, S.
    Pd(II)-bis(NHC) complexes (where NHC = N-heterocyclic carbene) bearing asymmetrically and symmetrically substituted NHC-ligand have been synthesized via deprotonation of 5,6-dimethylbenzimidazolium salts. The NHC precursors have been achieved via the two step N-alkylation of 5,6-dimethylbenzimidazole. The resultant salts were deprotonated with PdCl2 and K2CO3 in dry THF for 2(a-e). The obtained complexes were identified and characterized by H-1 and C-13 NMR, FT-IR, DART-TOF mass spectrometry and elemental analysis. These new Pd(II)-bis(NHC) complexes were applied as catalyst precursors for Suzuki-Miyaura cross-coupling reactions of aryl bromides and chlorides with phenylboronic acid to afford the corresponding products in good yields. This catalytic reaction was evaluated in the presence of KOtBu/toluene. The antibacterial activities of 2(a-e) were investigated against Gram (+)/(-) bacteria using the agar dilution procedure. The antibacterial activities of 2 vary with the nature of the ligands; MIC values of 2(a-e) were determined.
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    Efficient in situ N-heterocyclic carbene palladium(ii) generated from Pd(OAc)2 catalysts for carbonylative Suzuki coupling reactions of arylboronic acids with 2-bromopyridine under inert conditions leading to unsymmetrical arylpyridine ketones: synthesis, characterization and cytotoxic activities
    (Royal Soc Chemistry, 2018) Touj, Nedra; Al-Ayed, Abdullah S.; Sauthier, Mathieu; Mansour, Lamjed; Harrath, Abdel Halim; Al-Tamimi, Jamil; Ozdemir, Ismail
    N,N-Substituted benzimidazole salts were successfully synthesized and characterized by H-1-NMR, C-13 {H-1} NMR and IR techniques, which support the proposed structures. Catalysts generated in situ were efficiently used for the carbonylative cross-coupling reaction of 2 bromopyridine with various boronic acids. The reaction was carried out in THF at 110 degrees C in the presence of K2CO3 under inert conditions and yields unsymmetrical arylpyridine ketones. All N,N-substituted benzimidazole salts 2a-i and 4a-i studied in this work were screened for their cytotoxic activities against human cancer cell lines such us MDA-MB-231, MCF-7 and T47D. The N,N-substituted benzimidazoles 2e and 2f exhibited the most cytotoxic effect with promising cytotoxic activity with IC50 values of 4.45 g mL(-1) against MDA-MB-231 and 4.85 g mL(-1) against MCF7 respectively.
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    In situ palladium/N-heterocyclic carbene complex catalyzed carbonylative cross-coupling reactions of arylboronic acids with 2-bromopyridine under CO pressure: efficient synthesis of unsymmetrical arylpyridine ketones and their antimicrobial activities
    (Springer, 2019) Boubakri, L.; Al-Ayed, Abdullah S.; Mansour, L.; Harrath, A. A.; Al-Tamimi, J.; Ozdemir, I.; Yasar, S.
    The carbonylative Suzuki cross-coupling of 2-bromopyridine with various boronic acids to prepare unsymmetrical arylpyridine ketones has been carried out using palladium/N-heterocyclic carbene complexes as catalysts prepared in situ. The selectivity and the rate of these reactions are highly dependent on the conditions, i.e., nature of the palladium catalyst precursor, solvent, temperature and CO pressure. The main side-products arise from direct, non-carbonylative cross-coupling. Under the optimum conditions, arylpyridine ketones are recovered in high yields (60-88%). The antibacterial activities of the corresponding benzimidazole salts 2 were tested against Gram positive and negative bacteria using the agar dilution procedure, and their IC50 values have been determined.
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    Ru(ii)-N-heterocyclic carbene complexes: synthesis, characterization, transfer hydrogenation reactions and biological determination
    (Royal Soc Chemistry, 2019) Boubakri, Lamia; Chakchouk-Mtibaa, A.; Al-Ayed, Abdullah S.; Mansour, L.; Abutaha, Nael; Harrath, Abdel Halim; Mellouli, L.
    A series of ruthenium(ii) complexes with N-heterocyclic carbene ligands were successfully synthesized by transmetalation reactions between silver(i) N-heterocyclic carbene complexes and [RuCl2(p-cymene)](2) in dichloromethane under Ar conditions. All new compounds were characterized by spectroscopic and analytical methods. These ruthenium(ii)-NHC complexes were found to be efficient precatalysts for the transfer hydrogenation of ketones by using 2-propanol as the hydrogen source in the presence of KOH as a co-catalyst. The antibacterial activity of ruthenium N-heterocyclic carbene complexes 3a-f was measured by disc diffusion method against Gram positive and Gram-negative bacteria. Compounds 3d exhibited potential antibacterial activity against five bacterial species among the six used as indicator cells. The product 3e inhibits the growth of all the six tested microorganisms. Moreover, the antioxidant activity determination of these complexes 3a-f, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 '-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) as reagent, showed that compounds 3b and 3d possess DPPH and ABTS antiradical activities. From a concentration of 1 mg ml(-1), these two complexes presented a similar scavenging activity to that of the two used controls gallic acid (GA) and butylated hydroxytoluene (BHT). From a concentration of 10 mg ml(-1), the percentage inhibition of complexes 3b and 3d was respectively 70% and 90%. In addition, these two Ru-NHC complexes exhibited antifungal activity against Candida albicans. Investigation of the anti-acetylcholinesterase activity of the studied complexes showed that compounds 3a, 3b, 3d and 3e exhibited good activity at 100 mu g ml(-1) and product 3d is the most active. In a cytotoxicity study the complexes 3 were evaluated against two human cancer cell lines MDA-MB-231 and MCF-7. Both 3d and 3e complexes were found to be active against the tested cell lines showing comparable activity with examples in the literature.