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Hydrazone bond formation under physiological conditions remains challenging. In this study, bis(salicylaldehyde hydrazone) was synthesized using supramolecular catalysis under physiological conditions and its AT-DNA ratiometric sensing properties were ide

Reactions of triorgano-gallium and –indium etherates with N′-(2-hydroxybenzylidine)benzohydrazide and N′-(2-hydroxy-3-methoxybenzylidine)benzohydrazide in refluxing benzene afforded complexes of composition [{RM}{–O(C6H3R′-3)CH[dbnd]

Two new, binuclear copper(II) hydrazone complexes have been synthesized and characterized by various physico-chemical techniques including single crystal X-ray diffraction. Interaction of these complexes with nucleotide and protein were analyzed by in vit

Bioorthogonal site-specific chemical reaction to label biomolecules in vitro and in living cells is one of the most powerful and convenient tools in chemical biology. Reactive pairs frequently used for chemical conjugation are aldehydes/ketones with hydrazines/hydrazides/hydroxylamines. Although the reaction is generally specific for the two components, even in a cellular environment, the reaction is very slow under physiological conditions. Addition of a phosphate group at the ortho position of an aromatic aldehyde increases the reaction rate by an order of magnitude and enhances the aqueous solubility of the reagent and the product. We have synthesized phosphate-substituted aldehyde synthetic models to study kinetics of their reactions with hydrazines and hydrazides that contain a fluorophore. This rapid bioorthogonal reaction should therefore be potentially a very useful reaction for routine site-specific chemical ligations to study and image complex cellular processes in biological systems.

Three new transition metal complexes of a tridentate Schiff base ligand, H2L?=?N-(2-hydroxybenzylideneamino) benzamide, were synthesized in the presence of pyridine, 3-methylpyridine and the corresponding metal salts, and were characterized by

The reaction of the benzoylhydrazone of 2-hydroxybenzaldehyde (H 2L) with [MoO2(acac)2] proceeds smoothly in refluxing ethanol to afford an orange complex [MoO2L(C 2H5OH)] (1). The substrat

Antibody–drug conjugates (ADCs) are a new class of therapeutics that combine the lethality of potent cytotoxic drugs with the targeting ability of antibodies to selectively deliver drugs to cancer cells. In this study we show for the first time the synthesis of a reactive-oxygen-species (ROS)-responsive ADC (VL-DAB31-SN-38) that is highly selective and cytotoxic to B-cell lymphoma (CLBL-1 cell line, IC50 value of 54.1 nM). The synthesis of this ADC was possible due to the discovery that diazaborines (DABs) are a very effective ROS-responsive unit that are also very stable in buffer and in plasma. DFT calculations performed on this system revealed a favorable energetic profile (ΔGR=?74.3 kcal mol?1) similar to the oxidation mechanism of aromatic boronic acids. DABs’ very fast formation rate and modularity enabled the construction of different ROS-responsive linkers featuring self-immolative modules, bioorthogonal functions, and bioconjugation handles. These structures were used in the site-selective functionalization of a VL antibody domain and in the construction of the homogeneous ADC.

Benzoylhydrazone Schiff base–ligated three new ONO pincer–type palladium(II) complexes, [(PdL1(PPh3)] (1), [(PdL2(PPh3)] (2), and [(PdL3(PPh3)] (3), were synthesized by the reaction of the respective ligand, N-(2-hydroxybenzylidene)benzohydrazide (HL1), N-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (HL2), or N-(5-bromo-2-hydroxybenzylidene) benzohydrazide (HL3), with Pd(OAc)2 and PPh3 in methanol and isolated as air-stable reddish-orange crystalline solids in high yields (78%–83%). All three complexes were fully characterized by elemental analysis, Fourier-transform infrared spectroscopy, UV–Visible, 1H nuclear magnetic resonance (NMR), 13C{1H} NMR, and 31P{1H} NMR spectroscopic studies. The molecular structure of all three complexes was established unambiguously by single-crystal X-ray diffraction studies which revealed a distorted square planar geometry of all three complexes. The ONO pincer–type ligands occupied three coordination sites at the palladium, while the fourth site is occupied by the monodentate triphenylphosphine ligand. The catalytic potential of all three complexes was explored in the carbonylative Suzuki coupling of aryl bromides and iodides with arylboronic acids to yield biaryl ketones, using CHCl3 as the source of carbonyl. The reported protocol is convenient and safe as it obviates the use of carbon monoxide (CO) balloons or pressured CO reactors which are otherwise needed for the carbonylation reactions. The methodology has been successfully applied to the synthesis of two antineoplastic drugs, namely, phenstatin and naphthylphenstatin, in good yields (81% and 85%, respectively). Under the optimized reaction conditions, complex 2 exhibited the best catalytic activity in the carbonylative Suzuki couplings. The reported catalysts have wide reaction scope with good functional group tolerance. All catalysts could be retrieved from the reaction after completion and recycled up to three times with insignificant loss in the catalytic activity.

Tetrabromomethane functions as an organic catalyst for non-redox reactions of carbonyl species and, in particular, it enhances the aldehyde–acyl hydrazide condensation to give N-acyl hydrazones. This simple, inexpensive, and commercially available halomet

An efficient and BF3·Et2O-catalyzed chemoselective synthesis of diversified 1,3-diarylisobenzofuran in a high yield has been described. The reaction proceeds through sequential hydroarylation-cyclization between 2-formylarylketones and electron-rich arenes/heteroarenes. Advantageous features of the developed methodology include operational simplicity, a broad substrate scope, and applicability towards gram scale synthesis. The utility of isobenzofuran derivatives as the diene was extended to the synthesis of [4+2] cyclo-adducts with DMAD and the synthesis of 1,2-dicarbonylarenes in good yields.

Acylhydrazones formation has been widely applied in materials science and biolabeling. However, their sluggish condensation rate under neutral conditions limits its application. Herein, indolines with electron-donating groups are reported as a new catalyst scaffold, which can catalyze acylhydrazone, hydrazone, and oxime formation via an iminium ion intermediate. This new type of catalyst showed up to 15-fold rate enhancement over the traditional anilinecatalyzed reaction at neutral conditions. The identified indoline catalyst was successfully applied in hydrogel formation.

Although 2-hydroxybenzaldehyde acylhydrazones, such as salicylaldehyde acylhydrazones, are intriguing bioactive molecules, few of their N-alkylated derivatives are known, and only methyl analogues have been reported previously. We achieved selective N-alk

The purpose of this paper was to synthesis new mixed-ligand Cu(II) and Co(II) metal complexes utilizing bidentate and tridentate donor hydrazones derivatives as primary ligands and ortho-Vanillin as co-ligand. The obtained compounds were characterized by

Developing highly efficient catalyst systems to transform lignin biomass into value-added chemical feedstocks is imperative for utilizing lignin as renewable alternatives to fossil fuels. Recently, the pre-activated strategy involving the selective oxidat

Co(III) complexes of tridentate Schiff base ligands derived from N-(2-hydroxybenzylideneamino)benzamide (H2L1) and 2-(2-hydroxybenzylidene)hydrazine-1-carboxamide (H2L2) were synthesized and characterized using

Metal-free addition of salicylhydrazones to electron deficient internal alkynes catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) to yield oxa-bridged 2,6-epoxybenzo[b][1,5]oxazocine heterocycles was achieved. The demonstrated protocol proceeds through an o-quinone methide formation, aza-Michael addition, stereoselective protonation, enamine promoted aromatization, O,O-acetalization and O,N-aminalization sequence to provide privileged heterocycles in good yields with high diastereoselectivities.

Zn2+ plays fundamental roles in cellular metabolism and apoptosis, as well as neurotransmission. However, how to fast detect Zn2+ in biology is still challenging and meaningful. In this study, we rationally synthesized a simple OFF-O

A general and efficient visible light photocatalytic α-amino carbon radical-based cascade reaction of aroylhydrazones has been described. This protocol tolerates a wide array of α-silylamines and aroylhydrazones to afford the corresponding diversely funct

Constitutional dynamic libraries (CDLs) of hydrazones, acylhydrazones, and imines undergo reorganization and adaptation in response to chemical effectors (herein metal cations) via component exchange and selection. Such CDLs can be subjected to training by exposition to given effectors and keep memory of the information stored by interaction with a specific metal ion. The long-term storage of the acquired information into the set of constituents of the system allows for fast recognition on subsequent contacts with the same effector(s). Dynamic networks of constituents were designed to adapt orthogonally to different metal cations by up- and down-regulation of specific constituents in the final distribution. The memory may be erased by component exchange between the constituents so as to regenerate the initial (statistical) distribution. The libraries described represent constitutional dynamic systems capable of acting as information storage molecular devices, in which the presence of components linked by reversible covalent bonds in slow exchange and bearing adequate coordination sites allows for the adaptation to different metal ions by constitutional variation. The system thus performs information storage, recall, and erase processes.

Twelve bi-/tridentate Schiff-base ligands (L1-L12) have been designed, synthesized and coordinated with ion-exchanged Co-MOR (Mordenite) forming a series of Co-MOR(L) composite catalysts, for which various analyzes and characterizations are conducted. Selectively catalytic epoxidation of α-pinene with dry air over Co-MOR(L) catalysts has been carried out, where uses TBHP in small amounts as the initiator. Among these Co-MOR(L) catalysts, Co-MOR(L8) exhibits the best activity for the titled reaction to obtain 85.8 mol% conversion and 90.8% selectivity of epoxide. Some factors such as the structure of ligands, the oxidants, the solvents, the catalyst amount, the reaction temperature and time play important roles in controlling the epoxidation. The recyclable stability of the Co-MOR(L8) catalyst is confirmed. The studies on the electrochemical behaviors of Co species in Co-MOR(L8) reveal the importance of reversible change between Co oxidation states for the epoxidation.

Cobalt(iii) complexes of the type [Co(HL)(L)] were synthesized under solvothermal conditions staring from [Co(C5H7O2)3] and the corresponding ligand H2L (salicylaldehyde 4-hydroxybenzhydrazone, 3-meth

We use Schiff-base salicylaldehyde benzoylhydrazone (HL) as the ligand for copper(II), resulting in the complexes [CuCl(L)] · H2O (C1), [CuNO3(L)] · H2O (C2) and [CuBr(L)]2 (C3). We characterize the Cu(II) compo

Efficient synthetic procedures for the preparation of acid hydrazines and hydrazides were developed by converting the corresponding carboxylic acid into the methyl ester catalyzed by Amberlyst-15, followed by a reaction with hydrazine monohydrate. Sulfohydrazides were prepared from the corresponding sulfonyl chlorides and hydrazine monohydrate. Both of these group of compounds were condensed with substituted salicylaldehydes using gradient concentration methods that generated a large library of hydrazone, hydrazide and sulfohydrazide analogs. Antifungal activity of the prepared analogs showed that salicylaldehyde hydrazones and hydrazides are potent inhibitors of fungal growth with little to no mammalian cell toxicity, making these analogs promising new targets for future therapeutic development.

An efficient synthesis of substituted 1,3-dihydroisobenzofurans is developed. In this novel route, o-aroylbenzaldehydes, as key intermediates, can be obtained by lead tetraacetate oxidation of N-aroylhydrazones of salicylaldehydes. The mild and general st

The Mn-hydrazone Schiff base has been prepared, characterized, and encapsulated into NaY to prepare a new heterogeneous catalyst. Elemental analysis, UV-Vis, infrared spectroscopic analysis, diffuse reflectance spectroscopy, thermal analysis, small angle X-ray diffraction, and N2 sorption indicate the presence of Mn-hydrazone Schiff base within the nanocavity pores of zeolite-Y. The catalysts showed excellent catalytic efficiency in epoxidation with various olefinic compounds including cyclooctene, using tert-BuOOH as oxidant. Cyclooctene showed high conversion (97%) as well as epoxide selectivity (89%) with tert-BuOOH. Moreover, the encapsulated complex showed good recoverability without significant loss of activity and selectivity within successive runs.

We report here a Cu(II)-Schiff base complex that can assemble into one-dimensional (1D) nanoscale fibers, belts, and rods under different synthetic conditions. The ligand-structure effect is investigated by modification of the ligand structure. The format

In a study of the spectroscopic behavior of two Schiff base derivatives, salicylaldehyde salicylhydrazone (1) and salicylaldehyde benzoylhydrazone (2), Schiff base 1 has high selectivity for Zn2+ ion not only in abiotic systems but also in living cells. The ion selectivity of 1 for Zn2+ can be switched for Mg2+ by swapping the solvent from ethanol-water to DMF (N,N-dimethylformamide)-water mixtures. Imine 2 is a good fluorescent probe for Zn2+ in ethanol-water media. Many other ions tested, such as Li+, Na+, Al3+, K+, Ca 2+, Cr3+, Mn2+, Fe3+, Co 2+, Ni2+, Cu2+, Ag+, Cd 2+, Sn2+, Ba2+, Hg2+, and Pb 2+, failed to induce any spectral change in various solvents. The selectivity mechanism of 1 and 2 for metal ions is based on a combinational effect of proton transfer (ESPT), C=N isomerization, and chelation-enhanced fluorescence (CHEF). The coordination modes of the complexes were investigated.

Three tridentate or bidentate Schiff-base ligands inclusive of salicylaldehyde benzoylhydrazone (L1), vanillic aldehyde benzoylhydrazone (L2) and 4-methyl benzaldehyde benzoylhydrazone (L3), have been designed, synthesized and employed to coordinate with Co2+ ions and ion-exchanged Co-ZSM-5 forming several Co-L complexes and Co-ZSM-5(L) composite catalysts. The catalytic epoxidation of several alkenes with dry air has been carried out at 90 °C under atmospheric pressure using Co-L complexes and Co-ZSM-5(L) catalysts (using TBHP in small amounts as the initiator). In contrast, the catalysts Co-ZSM-5(L) shows higher catalytic activity than Co-ZSM-5 itself and Co-L complexes. Among three Co-ZSM-5(L) catalysts, Co-ZSM-5(L1) exhibits the highest activity for the selective epoxidation of alkenes. Recycling studies show the recyclability of Co-ZSM-5(L1) as a heterogeneous catalyst, which does not lose the catalytic activity after even eight reuses appreciably. Based on the experiments, one possible reaction mechanism is proposed.

The present invention relates to the use of mixtures containing hydrazone compounds and copper for controlling the growth of fungi.

(Chemical Equation Presented) A convenient, versatile, and regiospecific synthesis of functionalized 1,3-diarylisobenzofurans has been developed. It involves chemoselective addition of arylmagnesium reagents to the aldehyde function of o-aroylbenzaldehydes, themselves readily obtained by lead tetraacetate oxidation of N-aroylhydrazones of salicylaldehydes. Various functional groups, including nitro, iodo, or ester functionalities, have thus been positioned with complete regiospecificity on the 1,3-diphenylisobenzofuran backbone.

A simple, efficient and eco-friendly method for the synthesis of acylhydrazones from acylhydrazides and aldehydes under microwave (MW) irradiation was reported, no solvent and catalyst was used. The method is combined with a combinatorial approach and fou

The 2 percent cross-linked poly[styrene(iodoso diacetate)] was used to synthesis of 1,2-diacylbenzenes, which gave high yields, and could be recycled.

Methods of inhibiting fibrosis comprising administering certain pyridoxal benzoyl hydrazones or analogs thereof are disclosed. Preferred hydrazones are pyridoxal benzoyl hydrazone, 3-hydroxyisonicotinaldehyde benzoyl hydrazone and salicylaldehyde benzoyl hydrazone. The methods are useful in treating fibrosing disorders, including dermal fibrosing disorders, fibrosis of internal organs and fibrotic conditions of the eye.

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2'-Hydroxyacetophenone and 2'-hydroxypropiophenone acylhydrazones 3 are oxidized to 1,2-diacylbenzenes 4 using [(diacetoxy)iodo]benzene in dichloromethane at room temperature in a synthetically useful and high yield reaction.

Infrared spectra have been obtained for pyridoxal isonicotinoyl hydrazone, pyridoxal benzoyl hydrazone, salicylaldehyde isonicotinoyl hydrazone and salicylaldehide benzoyl hydrazone.Vibrational assignements are proposed mainly in the 2000-1200 cm-1/

Lanthanum(III), cerium(III), praseodymium(III), neodymium(III), samarium(III), gadolinium(III), terbium(III), dysprosium(III) and yttrium(III) complexes of salicylaldehyde benzoyl hydrazone (H2L), salicylaldehyde 2-picoloyl hydrazone (H2L'), and of o-hydr

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Magnesium(II), zinc(II), cadmium(II), mercury(II) and lead(II) complexes of (substituted) salicylidene-benzoyl hydrazide, salicylidene-2-picoloyl hydrazide, salicylidene-2-quinoloyl hydrazide and salicylidene-8-quinoloyl hydrazide schiff bases have been s

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