- Molybdenum(VI) complexes with tridentate Schiff base ligands derived from isoniazid as catalysts for the oxidation of sulfides: synthesis, X-ray crystal structure determination and spectral characterization
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Two new complexes, including [MoO2(L1)(CH3OH)] and [MoO2(L2)(CH3OH)], with tridentate ONO–donor Schiff base ligands (H2L1: (E)-N'-(2-hydroxy-3-methoxybenzylidene)isoni
- Kargar, Hadi
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- Synthesis and characterization of a series of isoniazid hydrazones. Spectroscopic and theoretical study
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A family of hydrazones of isoniazid and a group of hydroxybenzalaldehydes (vanillin, 5-bromovanillin, 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde) were obtained and fully characterized. The results, including theoretical data, are comparatively ana
- Ferraresi-Curotto, Verónica,Echeverría, Gustavo A.,Piro, Oscar E.,Pis-Diez, Reinaldo,González-Baró, Ana C.
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p. 436 - 447
(2016/12/27)
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- Potent antimicrobial agents against azole-resistant fungi based on pyridinohydrazide and hydrazomethylpyridine structural motifs
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Abstract Schiff base derivatives have recently been shown to possess antimicrobial activity, and these derivatives include a limited number of salicylaldehyde hydrazones. To further explore this structure-activity relationship between salicylaldehyde hydrazones and antifungal activity, we previously synthesized and analyzed a large series of salicylaldehyde and formylpyridinetrione hydrazones for their ability to inhibit fungal growth of both azole-susceptible and azole-resistant species of Candida. While many of these analogs showed excellent growth inhibition with low mammalian cell toxicity, their activity did not extend to azole-resistant species of Candida. To further dissect the structural features necessary to inhibit azole-resistant fungal species, we synthesized a new class of modified salicylaldehyde derivatives and subsequently identified a series of modified pyridine-based hydrazones that had potent fungicidal antifungal activity against multiple Candida spp. Here we would like to present our synthetic procedures as well as the results from fungal growth inhibition assays, mammalian cell toxicity assays, time-kill assays and synergy studies of these novel pyridine-based hydrazones on both azole-susceptible and azole-resistant fungal species.
- Backes, Gregory L.,Jursic, Branko S.,Neumann, Donna M.
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p. 3397 - 3407
(2015/08/03)
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- Heteroleptic binuclear copper(I) complexes bearing bis(salicylidene)hydrazone ligands: Synthesis, crystal structure and application in catalytic N-alkylation of amines
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A new series of heteroleptic binuclear Cu(I) bis(salicylidene)hydrazone complexes (1-4) bearing triphenylphospine coligands have been synthesized from the reactions of copper(II) precursor complex [CuCl2(PPh3)2] with oxadiazole compounds A-D, respectively. It has been observed that the oxadiazole compounds undergo ring cleavage with in situ reduction of Cu(II) ion, during the formation of complexes (1-4). The oxadiazoles (A-D) and the Cu(I) complexes (1-4) have been characterized by analytical and spectroscopic methods. Single crystal X-ray diffraction study of complex 2 has revealed a distorted tetrahedral geometry around each Cu(I) center. Catalytic efficiency of the new complexes on the N-alkylation of amines using alcohols was studied under optimized conditions. The new complexes have also been tested for their catalytic activity towards the direct N-alkylation of 2-nitropyridine.
- Prakash, Govindan,Nirmala, Muthukumaran,Ramachandran, Rangasamy,Viswanathamurthi, Periasamy,Malecki, Jan Grzegorz,Sanmartin, Jesus
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- Ruthenium(II) bis(hydrazone) complexes derived from 1,3,4-oxadiazoles: Synthesis, crystal structure and catalytic application in N-alkylation reactions
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1,3,4-Oxadiazoles (A-C) were derived via a series of reactions between isoniazid and salicylaldehydes. While reacting the oxadiazoles with [RuHCl(CO)(PPh3)3] in the presence of NaOH, mononuclear ruthenium(II) complexes bearing 'salen' type N,N′-bis(salicylidene)hydrazone ligands (1-3) were obtained. The oxadiazoles and ruthenium(II) complexes were characterized by analytical and spectral methods. The single crystal XRD analyses of complexes 1 and 2 suggested an octahedral geometry around ruthenium(II) ions in which the bis(hydrazone) act as mononegative bidentate ligands. It was also observed that the presence of an intramolecular hydrogen bonding between the hydroxyl proton and one of the azomethine nitrogens in all the complexes. Further, the complexes were proved as versatile catalysts for the N-alkylation of amines with alcohols under optimized reaction conditions.
- Prakash, Govindan,Ramachandran, Rangasamy,Nirmala, Muthukumaran,Viswanathamurthi, Periasamy,Sanmartin, Jesus
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supporting information
p. 203 - 210
(2015/01/30)
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- Ruthenium(II) hydrazone Schiff base complexes: Synthesis, spectral study and catalytic applications
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Ruthenium(II) hydrazone Schiff base complexes of the type [RuCl(CO)(B)(L)] (were B = PPh3, AsPh3 or Py; L = hydrazone Schiff base ligands) were synthesized from the reactions of hydrazone Schiff base ligand (obtained from isonicotinoylhydrazide and different hydroxy aldehydes) with [RuHCl(CO)(EPh3)2(B)] (where E = P or As; B = PPh 3, AsPh3 or Py) in 1:1 molar ratio. All the new complexes have been characterized by analytical and spectral (FT-IR, electronic, 1H, 13C and 31P NMR) data. They have been tentatively assigned an octahedral structure. The synthesized complexes have exhibited catalytic activity for oxidation of benzyl alcohol to benzaldehyde and cyclohexanol to cyclohexanone in the presence of N-methyl morpholine N-oxide (NMO) as co-oxidant. They were also found to catalyze the transfer hydrogenation of aliphatic and aromatic ketones to alcohols in KOH/Isopropanol.
- Manikandan,Viswanathamurthi,Muthukumar
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experimental part
p. 297 - 303
(2011/12/13)
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