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Öğe 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.Öğe N-Heterocyclic carbene-Pd(II)-PPh3 complexes as a new highly efficient catalyst system for the Sonogashira cross-coupling reaction: Synthesis, characterization and biological activities(Taylor & Francis Ltd, 2018) Boubakri, L.; Mansour, L.; Harrath, A. H.; Ozdemir, I.; Yasar, S.; Hamdi, N.A novel series of N-heterocyclic carbene-phosphine palladium(II) complexes has been synthesized and fully characterized by IR, H-1 NMR, C-13 NMR, and P-31 NMR spectroscopies, and elemental analysis. The new N-heterocyclic carbene (NHC)-phosphine palladium(II) complexes 3a-h have been easily prepared by the reaction of the corresponding PEPPSI (pyridine-enhanced precatalyst preparation stabilization and initiation) complexes 2a-h and triphenylphosphine in dichloromethane in high yields. These complexes were applied as catalyst precursors which efficiently catalyzed Sonogashira reactions between aryl bromides and phenylacetylene to afford the corresponding products in good yields. The bulky NHC-Pd-PPh3 complexes 3 were tested against Gram-positive and Gram-negative bacteria to study their biological activity. All the complexes exhibit antibacterial against these organisms. Investigation of the antiacetylcholinesterase activity of the studied complexes showed that compounds 3a and 3b exhibited moderate activity at 100 mu g mL-1 and product 3b is the most active.Öğe Substituted N-heterocyclic carbene PEPPSI-type palladium complexes with different N-coordinated ligands: Involvement in the direct C-H bond activation of heteroarenes derivatives with aryl bromide and their antimicrobial, anti-inflammatory and antioxidant activities(Elsevier Science Sa, 2022) Slimani, I; Boubakri, L.; Ozdemir, N.; Mansour, L.; Ozdemir, I; Gurbuz, N.; Yasar, S.In this study new benzimidazolium salt as N-heterocyclic carbene precursors and their related new PEPPSI-Pd (II)-N-heterocyclic carbene (NHC) complexes 3a-e were prepared and caracterized. The structures of all compounds have been characterized by H-1 NMR, C-13 NMR, and IR spectroscopy, as well as elemental analysis techniques and Direct analysis in real time (DART)-time-of-flight mass spectrometry (TOF-MS), which support the proposed structures. Further confirmations of structural details were provided by a single-crystal X-ray. A single crystal of PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complex 3c shows that the coordination geometry around Pd slightly distorted square-planar geometry. Next, the PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e were used as catalysts in the direct C-5-arylation of 2-acetyl furan and 2-acetylthiophene with various aryl bromides. These complexes exhibited moderate to high catalytic activities and gave C-H activation selectively at the C-5-position. Further, PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e have been evaluated for their potential antibacterial properties against a panel of bacterial strains namely, Micrococcus luteus, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus, candida albican and pseudomonas aeruginosa. In addition; these new PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e were investigated for anti-oxidant activities by super oxide radical; DPPH (2,2-Diphenyl-1-picrylhydrazyl); and hydroxyl radical scavenging assays; in which most of them displayed significant antioxidant activities. Furthermore; PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e were evaluated for anti-inflammatory activity by indirect haemolytic and lipoxygenase inhibition assays and revealed good activity.Öğe Synthesis and catalytic applications of palladium N-heterocyclic carbene complexes as efficient pre-catalysts for Suzuki-Miyaura and Sonogashira coupling reactions(Royal Soc Chemistry, 2017) Boubakri, L.; Yasar, S.; Dorcet, V.; Roisnel, T.; Bruneau, C.; Hamdi, N.; Ozdemir, I.A new palladium complex series with N-heterocyclic carbene (NHC), pyridine and phosphine ligands, PdCl2(L)NHC (2a-c)(L = NHC), PdCl2(L-1)NHC(3a-c)(L-1 = pyridine), PdCl2(L-2)NHC(4a-c)(L-2 = triphenyl-phosphine) was synthesised and fully characterized. The catalytic activities of these complexes were screened for the Sonogashira and Suzuki-Miyaura reactions between arylhalides and phenylacetylene, and phenylboronic acid, respectively. The results pointed out that the carbene/phosphine complexes 4a-c exhibited excellent catalytic activities as compared to 2a-c, 3a-c, and the well-known systems for the palladium-catalysed Sonogashira reaction. The reactivity of 4a-c in these preliminary Sonogashira coupling tests seems to be higher than that of previously reported catalytic systems based on Pd(NHC) moieties. These new palladium NHC complexes are among the first reported palladium catalysts that are efficient for catalysing the Sonogashira reaction from arylchloride substrates.
