Showing papers on "Hydrazone published in 2015"
TL;DR: Increase in activity observed for compounds 2 to 34 clearly highlights the importance of flavone, hydrazide and hydrazone linkage in suppressing the activity of α-glucosidase.
117 citations
TL;DR: The use of formaldehyde N,N-dialkylhydrazones as neutral C1-nucleophiles in the iridium-catalyzed substitution of allylic carbonates is described for two processes, which allows for the construction of optically active allylic nitriles and dithiolanes as well as branched α-aryl aldehydes.
Abstract: The use of formaldehyde N,N-dialkylhydrazones as neutral C1-nucleophiles in the iridium-catalyzed substitution of allylic carbonates is described for two processes. Kinetic resolution or, alternatively, stereospecific substitution affords configurationally stable α,α-disubstituted aldehyde hydrazones in high enantiomeric excess and yield. This umpolung approach allows for the construction of optically active allylic nitriles and dithiolanes as well as branched α-aryl aldehydes. A catalyst-controlled reaction with Enders' chiral hydrazone derivatives followed by diastereoselective nucleophilic addition to the hydrazone products constitutes a two-step stereodivergent synthesis of chiral amines.
85 citations
TL;DR: The discovery of two new classes of catalysts for hydrazone and oxime formation in water at neutral pH, namely 2-aminophenols and 2-(aminomethyl)benzimidazoles, is reported.
80 citations
TL;DR: The hydrazone Schiff base ligands have been used to synthesize the following MnII complexes: the mononuclear complex [Mn(HL1 )2][ClO4]2· 2H2O (1), the cocrystallized discrete dinuclear complex {[Mn[HL1 ]2]· [mn(L 1 ]2]}[ClO 4]2]2 (2), and the phenoxido-bridged dinuclear Complex [Mm(μ•HL2 )(H 2O)]2[Cl
Abstract: The hydrazone Schiff base ligands (E )‐N′‐(2‐hydroxybenzylidene)acetohydrazide (HL1 ) and (E )‐N′‐(2,3‐dihydroxybenzylidene)acetohydrazide (H2L2 ) with a functional group variation in the aromatic moiety have been synthesized. The ligands have been used to synthesize the following MnII complexes: the mononuclear complex [Mn(HL1 )2][ClO4]2· 2H2O (1 ), the cocrystallized discrete dinuclear complex {[Mn(HL1 )2]· [Mn(L1 )2]}[ClO4]2 (2 ), and the phenoxido‐bridged dinuclear complex [Mn(μ‐HL2 )(H2O)]2[ClO4]2 (3 ). The ligands and the complexes were characterized by FTIR and UV/Vis spectroscopic techniques, and their crystal structures were determined by single‐crystal X‐ray diffraction analysis. 1H and 13C NMR spectroscopy shows evidence of keto–enol tautomerism of the ligands in solution. All of the compounds develop hydrogen‐bonded assemblies of different dimensionalities and architectures. CH–π and π–π interactions also contribute significantly to the overall binding energies of the supramolecular assemblies. The supramolecular interaction energies have been computed at the BP86‐D3/def2‐TZVPD level of theory.
75 citations
TL;DR: A serendipitous discovery has led to a new hydrazone-based low molecular weight fluorescent super-hydrogelator that can be switched "ON" and "OFF" using pH, enabling the sensing of biogenic amines emanating from spoiled cod.
68 citations
TL;DR: In this paper, two new cis-MoO2 [MoO 2(L)(EtOH)] (1), MoO2(L)Py [L: (3-methoxy-2oxidobenzylidene)benzohydrazidato], complexes have been synthesized and fully characterized on the basis of elemental analysis, FT-IR, molar conductivity, 1H NMR, 13C NMR and electronic spectra.
62 citations
TL;DR: A hydrazone-based carbene/alkyne cascade produced a variety of bridged and fused polycyclic products and a key mechanistic intermediate, a ring-fused cyclopropene, has been isolated and characterized.
Abstract: A hydrazone-based carbene/alkyne cascade produced a variety of bridged and fused polycyclic products. NaOSiMe3 is a superior base for conversion of hydrazones to diazoalkanes. A key mechanistic intermediate, a ring-fused cyclopropene, has been isolated and characterized.
61 citations
TL;DR: It is shown that an ortho boronic acid substituent makes aryl ketones rapidly conjugate with α-nucleophiles at neutral pH, comparable to the fastest bioorthogonal conjugations known to date.
Abstract: Bioorthogonal reactions that are fast and reversible under physiological conditions are in high demand for biological applications. Herein, it is shown that an ortho boronic acid substituent makes aryl ketones rapidly conjugate with α-nucleophiles at neutral pH. Specifically, 2-acetylphenylboronic acid and derivatives were found to conjugate with phenylhydrazine with rate constants of 10(2) to 10(3) M(-1) s(-1) , comparable to the fastest bioorthogonal conjugations known to date. (11) B NMR analysis revealed the varied extent of iminoboronate formation of the conjugates, in which the imine nitrogen forms a dative bond with boron. The iminoboronate formation activates the imines for hydrolysis and exchange, rendering these oxime/hydrazone conjugations reversible and dynamic under physiological conditions. The fast and dynamic nature of the iminoboronate chemistry should find wide applications in biology.
60 citations
TL;DR: A novel series of N-arylidene-2-(2,4-dichloro phenyl)-1-propyl-1H-benzo[d] imidazole-5-carbohydrazides having different substitution on the arylidene part were synthesized in good yield, and exhibited remarkable paw-edema inhibition in the initial one hour of administration indicating the higher potentiality of these molecules.
57 citations
TL;DR: A new complex of Co(III) using an oxidative stable hydrazone ligand, CoL, was synthesized and characterized by elemental analysis, spectroscopic methods and single crystal X-ray analysis, revealing that the complex is mononuclear and the coordination environment around the Co( III) core is trans-[CoN4Cl2].
Abstract: A new complex of Co(III) using an oxidative stable hydrazone ligand, CoL, was synthesized and characterized by elemental analysis, spectroscopic methods and single crystal X-ray analysis where HL is bis-[(E)-N'-(phenyl(pyridin-2-yl)methylene)]carbohydrazide. X-ray analysis revealed that the complex is mononuclear and the coordination environment around the Co(III) core is trans-[CoN4Cl2]. The catalytic activity of the complex in the oxygen reduction reaction was investigated. The complex is a highly oxidative resistant cobalt-hydrazone which can efficiently catalyze the reduction of oxygen (O2) by a weak electron donor ferrocene, (Fc), at the polarized water/1,2-dichloroethane (DCE) interface. Oxygen reduction is coupled with proton transfer from water to the organic phase to form hydrogen peroxide, which is extracted into the aqueous phase.
40 citations
TL;DR: The first examples of catalytic cyclization reactions between the Huisgen zwitterion and α-ketoester derivatives are reported, furnishing either the corresponding cycloadducts or the hydrazone derivatives in moderate to good yields.
TL;DR: The antiproliferative activity of all dioxidovanadium(V) complexes was studied, which reveal all compounds are significantly cytotoxic towards the HeLa cell line.
TL;DR: In this article, the synthesis of three new palladium(II) complexes bearing heterocyclic hydrazone ligands is presented along with their structural characterization using IR, 1H and 13C NMR spectra.
Abstract: Facile synthesis of three new palladium(II) complexes bearing heterocyclic hydrazone ligands are presented along with their structural characterization using IR, 1H and 13C NMR spectra. Molecular structures of the complexes determined by single-crystal XRD revealed a distorted square-planar geometry around the metal ion to which the hydrazone was attached in a tridentate fashion. Catalytic activity of these complexes tested towards the Suzuki–Miyaura cross coupling reaction of substituted aryl boronic acids with aryl chlorides in a water–toluene system (90 : 10%) without using any promoting additives or phase transfer agents, proved that they are highly active with 0.01 mol% loading under optimized conditions to afford 99% yield of the coupled product. Effects of temperature, solvent and base on the cross-coupling reaction were carried out as well. These complexes showed significant catalytic activity up to five cycles.
TL;DR: A new series of quinoline hydrazone derivatives and their metal complexes have been synthesized and their biological properties have been evaluated against Mycobacterium tuberculosis (H37 RV strain).
Abstract: A new series of quinoline hydrazone derivatives and their metal complexes have been synthesized and their biological properties have been evaluated against Mycobacterium tuberculosis (H37 RV strain). Most of the newly synthesized compounds displayed 100% inhibitory activity at a concentration of 6.25–25 μg/mL, against Mycobacterium tuberculosis. Fluorescence properties of all the synthesized compounds have been studied.
TL;DR: In this paper, an o-methoxybenzaldehyde benzoylhydrazone (MBH) was synthesized and fully characterized by elemental analysis, FTIR, 1 HNMR and mass spectra.
TL;DR: In this paper, two new binuclear Cu(II and Co(II) and mononuclear Ni(II)-complexes of the flexible hydrazone Schiff base, (E)-N′-(1-(2-aminophenyl) ethylidene)-2-oxo-2-(phenylamino) acetohydrazide (H 2 AAH) have been synthesized and characterized by conventional techniques.
TL;DR: A series of phosphine-functionalized hydrazone/thiosemicarbazone ligands and their corresponding ruthenium(II) carbonyl complexes of the type [RuCl(CO)(AsPh3)(L)] were characterized by elemental analyses and various spectral methods as discussed by the authors.
TL;DR: In this paper, a novel fluorescent Al 3+ -sensor (8-Hydroxyquinoline-7-aldehyde-(2′-methylquinoline)-4′-formyl hydrazone, L 1 ) based on quinoline derivative has been designed and synthesized.
TL;DR: A new hydrazone Schiff base, (E)-N′-(3-ethoxy-2-hydroxybenzylidene)isonicotinohydrazide (H2L), has been prepared and characterized by elemental analyses, spectroscopic methods, and single-crystal X-ray diffraction as discussed by the authors.
Abstract: A new hydrazone Schiff base, (E)-N′-(3-ethoxy-2-hydroxybenzylidene)isonicotinohydrazide (H2L), has been prepared and characterized by elemental analyses, spectroscopic methods, and single-crystal X-ray diffraction. The corresponding dioxomolybdenum(VI) complex [Mo(O)2(L)(CH3OH)] was synthesized and characterized by spectroscopic methods and by single-crystal X-ray diffraction. The hydrazone ligand coordinates to Mo through the phenolate O, imine N, and enolic O. The Mo center displays a distorted octahedral geometry with the three donors of the ligands and an oxo defining the equatorial plane, and one methanol and another oxo occupying the axial positions.
TL;DR: Metal(II) coordination compounds of a tridentate hydrazone ligand (HL) derived from the condensation of cephalexin antibiotic with 2-hydrazinopyridine were synthesized and studied on three bacteria strains by agar diffusion disc method.
TL;DR: In this article, the trifluoromethylation of N,N-disubstituted hydrazones using the Togni reagent is demonstrated to proceed efficiently for aliphatic aldehyde-derived substrates.
Abstract: The copper-catalyzed C(sp2)¢H trifluoromethylation of N,N-disubstituted hydrazones using the Togni reagent is demonstrated to proceed efficiently for aliphatic aldehyde-derived substrates. The success of the reactions relied on the choice of the N,N-diphenylamino group as the terminal hydrazone amino group where N,N-dialkylamino groups were preferred for (hetero)aromatic aldehyde-derived substrates. In addition, the trifluoromethylated N-arylhydrazones are shown to be ideal substrates for Fischer indole synthesis allowing a straightforward, three-step access to 2-trifluoromethylindole derivatives from simple aldehydes.
TL;DR: In this paper, a triazolo(4,3-a) pyrimidin-5(1H)-one derivatives were converted with dierent aldehydes to give the corresponding hydrazone derivatives 15a{f.
Abstract: The reaction of thione 3 or its 2-methylthio derivative 4 with hydrazonoyl halides 5a{l, in the presence of triethylamine, yielded the corresponding triazolo(4,3-a)pyrimidin-5(1H)-ones 8a{l. The structure of compounds 8a{l was further conrmed by the reaction of 3 with the appropriate active chloromethylenes 11a{c followed by coupling of the products with benzenediazonium chloride to aord the azo-coupling products 6b, f, and j, which were converted in situ to 8b, f, and j. 2-Hydrazinyl-pyrido(3',2':4,5)thieno(3,2-d)pyrimidin-4(3H)-one (13) was prepared and condensed with dierent aldehydes{f to give the corresponding hydrazone derivatives 15a{f. Oxidative cyclization of the hydrazones 15a{f give the corresponding triazolo(4,3-a) pyrimidin-5(1H)-one derivatives 16a{f. The antimicrobial activity of the products was evaluated and the results revealed that compounds 8f and 15f showed strong activity against gram-positive bacteria while compound 15d showed the highest activity against gram- negative bacteria. Moreover, compounds 15b, 8d, 8e, 8c, 8l, and 8j exhibited signicant antifungal activity. In addition, the antitumoral activity of the synthesized products against dierent cancer cell lines was determined and the results revealed that compound 12c was the most active against MCF-7, HepG-2, HCT-116, and HeLa with IC50 values of 0.51, 0.72, 0.95, and 0.95, respectively, as compared with doxorubicin as positive control.
TL;DR: All the derivatives showed good CNS depressant activity and showed protection in the MES test, indicative of their ability to inhibit the seizure spread, and were nontoxic.
Abstract: A series of 2-(substituted-phenyl)-3-(2-oxoindolin-3-ylidene)amino)-thiazolidin-4-one derivatives were designed and synthesized under microwave irradiation, using an eco-friendly, efficient, microwave-assisted synthetic protocol that involves cyclocondensation of 3-substituted benzylidine-hydrazono-indolin-2-one 3a-j with thioglycolic acid in dimethyl formamide (DMF) as solvent and anhydrous zinc chloride as a catalyst, keeping in view the structural requirement of the pharmacophore. The intermediate compounds 3a-j were obtained by condensation of the hydrazone of indoline-2,3-dione with aromatic aldehydes. The synthesized derivatives were evaluated for CNS depressant activity and anticonvulsant activity in mice using the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (sc-PTZ) induced seizure tests. All the derivatives showed good CNS depressant activity and showed protection in the MES test, indicative of their ability to inhibit the seizure spread. A histopathological study was performed to evaluate liver toxicity caused by the synthesized compounds. The compounds were nontoxic. A computational study was performed, in which log P values were calculated experimentally. Virtual screening was performed by molecular docking of the designed compounds into the ATP binding sites of the NMDA and AMPA receptors, to predict if these compounds have analogous binding modes.
TL;DR: Metal(II) coordination compounds of a hydrazone ligand (HL) derived from the condensation of cephalexin antibiotic with 2,6-diacetylpyridine bis(hydrazone) ligand HL behaves as a monoanionic tetradentate NNNO chelating agent.
TL;DR: In this article, the energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital has been calculated using the theoretical computations to reflect the chemical reactivity and kinetic stability of compounds.
TL;DR: A series of novel 17-exo-oxadiazole and -thiadiazoles in the Δ(5) androstene series were efficiently synthesized from pregnenolone acetate and pregnadienol one acetate via multistep pathways to enlarge the compound library available for pharmacological studies.
TL;DR: In this paper, a new series of phenylazo indole dyes was synthesized and the structures of the dyes were confirmed by UV-vis, FT-IR, HRMS and 1H/13C NMR spectroscopic techniques.
TL;DR: In this paper, the main issues of structure and reactivity of active substrates and the influence of the reaction conditions and catalysts on the reaction regioselectivity and efficiency are discussed.
Abstract: The [2+2]-, [4+2]- and [3+2]-cycloaddition reactions of hydrazones and 1,2-diazabuta-1,3-dienes, azomethine imines, nitrile imines and azomethine ylides formed upon hydrazone transformations with dienophiles, dipolarophiles and dienes are considered. The principal issues of structure and reactivity of active substrates and the influence of the reaction conditions and catalysts on the reaction regioselectivity and efficiency are discussed. The bibliography includes 288 references.
TL;DR: The dual activation of acyl phosphonates and formaldehyde tert-butyl hydrazone by a BINAM-derived bis-urea catalyst is the key to achieve high reactivities and enantioselectivities in the synthesis of densely functionalized quaternary α-hydroxy phosphonate.
TL;DR: All the newly synthesized compounds were found to be more potent antifungal agents than reference drug against Candida albicans, whereas except 3e all other compounds also shown good activity against Saccharomyces cerevisiae.
Abstract: In the present investigation, ten new 2-((3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)-1-(4,6-dimethylpyrimidin-2-yl)hydrazine (3a–j) having pyrimidinyl and pyrazolyl moieties were synthesized. Structures of all compounds were confirmed by their spectral and elemental data. Most of the tested compounds were found to be significantly more effective against bacterial strains Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa than the reference drug ciprofloxacin. All the newly synthesized compounds were found to be more potent antifungal agents than reference drug against Candida albicans, whereas except 3e all other compounds also shown good activity against Saccharomyces cerevisiae.