Hydroxylamine Hydrochloride In Presence Research Articles

Synthesis, structure, characterization and one pot catalytic activity of half-sandwich iridium(III) complexes

A series of stable mononuclear half-sandwich iridium(III) complexes of the general formula [(η5-C5Me5)Ir(L)Cl](BPh4) has been synthesized in dry methanol using different imino pyridine ligands (L1–L6) and [(η5-C5Me5)2Ir2(µ-Cl)2Cl2] in a 2:1 molar ratio. All complexes were fully characterized by melting point, CHN analysis, FT-IR, UV–visible, 1H NMR, 13C NMR spectroscopy and mass spectrometry. The structure of complex 3 [(η5-C5Me5)Ir(L3)Cl](BPh4) was determined by single crystal X-ray structure analysis, showing a chelating coordination mode of the imino pyridine L3. One pot organic transformations of aldehyde to amide were carried out by complexes 1–6 in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate. The catalytic activity of complex 3 was found to be excellent, showing high conversion with catalytic turnover frequency up to 500.

Synthesis, characterization, electron paramagnetic property and catalytic amidation of binuclear ruthenium(III) complexes

A series of new binuclear ruthenium(III) complexes [ Ru2Cl4(EPh3)4(L)] (E = P or As) were successfully synthesized from 1:2 mol ratio of bi-nucleating ligand precursors (L1H2-L3H2) and [RuCl3(EPh3)3] in benzene for 6 h. The complexes were characterized by elemental analysis, FT-IR, UV–vis, magnetic susceptibility measurements and EPR spectroscopy methods. Rhombic distortion (gx ≠ gy ≠ gz) around the ruthenium ion was confirmed by EPR spectra in liquid nitrogen temperature. Catalytic activity of the facile one pot amidation reaction has been developed. The complex [Ru2Cl4(AsPh3)4(L1)](4) was found to possess excellent conversion up to 100 % of amide in toluene with the presence of hydroxylamine hydrochloride and NaHCO3 at 110 °C in 2 h. The effect of time, temperature, solvents and different catalytic loading experiments was also investigated.

Design, Synthesis, Evaluation of Antitubercular and Antioxidant Activity of Isoxazoline Derivatives Derived from Novel Chalcone Intermediates

Tuberculosis (TB), a bacterial infection caused by Mycobacterium tuberculosis (M-TB) is a fatal disease associated with a high degree of mortality. Present work involved synthesis of a series of novel isoxazoline derivatives (ISOA1-ISOA8) the new antitubercular agents using newly synthesized chalcones (CHL1-CHL8). This was done by subjecting the chalcones to a reaction with hydroxylamine hydrochloride in presence of acetic acid and sodium acetate. The structure of the synthesized compounds was elucidated by IR, 1H NMR and mass spectra. In silico studies of isoxazoline were performed for antitubercular activity by using an enoyl acyl carrier protein (EACP) reductase enzyme. Compound ISOA4 exhibited the best interaction among all these compounds having a docking score of -5.94 compared to standard drug pyrazinamide -6.1. Using in vitro models, purified compounds were tested for their antioxidant and antitubercular properties. Compound ISOA5 showed a significant antioxidant activity compared to ascorbic acid as a standard drug. This study claims new isooxazolines to possess high antioxidant and antitubercular potential, however they must be evaluated for preclinical and clinical significance.

TiO2/SO42- Solid Superacid: A Rapid, Solventless, Recoverable Nanocatalyst for Eco-Friendly Synthesis of Piperidin-4-one Oximes

: A potent, eco-friendly approach for converting 2,6-arylpiperidin-4-ones into their corresponding oximes in the presence of hydroxylamine hydrochloride and catalysed by nanosize sulfated titania (TiO2/SO4 2-) solid superacid was developed. Sol-gel method was employed to synthesize the catalyst and confirmed standard characterization techniques viz., by FT-IR, XRD, TEM, SEM, and EDS analysis. After adding 0.05 g of catalyst, the reaction was carried out under stirring in an oil bath at 130oC for 3-7 min under solvent-free conditions. This approach has advantages like catalyst recyclability, high yields, shorter reaction time, and simple work-up. Additionally, the catalyst TiO2/SO4 2- exhibited good stability, recoverability, and reusability for five consecutive runs without tremendous loss in its catalytic activity. The compounds 3a-o were characterised by IR, 1H and 13C NMR spectral analysis. The coupling constant values in NMR results suggested that the compounds 3a-o exhibit chair conformation with equatorial orientations with all the substituents. This is in agreement with the X-ray crystallography of 3c, confirming that the chair conformation of =N-OH group is syn to C-5 and anti to benzyl group at C-3 and hence if forms more stable (E)-configuration of the oxime 3c.

Synthesis and Characterization of New Pyrazoline and Isoxazoline Derivatives Based on Fluorene

The aim of the present work is a synthesis of new fluorene derivatives containing heterocyclic moieties. These compounds were synthesized in four groups, each group containing five compounds. The first group was made up of 2-(3-aryl-2-propenoyl) fluorene derivatives (1a-e) synthesized from the reaction of 2-acetyl fluorene with appropriate aromatic aldehyde in the presence of sodium hydroxide. The other three groups involved compounds produced from the reaction of (1a-e) with hydrazine hydrate (99%) in presence of acetic acid (96%) to give 1-acetyl-5-aryl-3-(fluoren-2-yl) pyrazoline derivatives (2a-e), and with phenyl hydrazine in presence of piperidine to produce 1-phenyl-5-aryl-3-(fluoren-2-yl) pyrazoline derivatives (3a-e), and with hydroxylamine hydrochloride in presence of pyridine to obtain the 5-aryl-3-(fluoren-2-yl) oxazoline derivatives (4a-e). All the compounds of the above three groups were substituted at position (5) in pyrazoline and isoxazoline ring with different aryl groups according to aromatic aldehyde used in the preparation of the first group series compounds. The synthesized compounds were identified by spectroscopic methods: FT-IR and 1H-NMR

Synthesis of Novel Biaryl Fused Thiazolo[3,2-b][1,2,4]triazol-2-amines from Thiazole Amine Involving Suzuki Coupling Reaction under Microwave Irradiation

Novel series of fused heterocycles in which amino triazole fused to biphenyl thiazole were synthesized in a multistep reaction starting from 2-aminothiazole. The amino compound with ethoxy carbonyl isothiocyanate afforded the ethyl carbamate thiomide derivative of thiazole, which further underwent intramolecular cyclization with hydroxyl amine hydrochloride in presence of DIPEA to furnish the fused thiazolotriazole amine. Haloaryl group in the fused heterocycle under Suzuki coupling condition afforded biphenyl derivatives of fused thiazolotriazole amines. All the synthesized compounds were confirmed based on their spectral data.

Synthesis of Some Novel Isoxazoline from Sec 3-Amino Pyridazine Chalcones and Their Antimicrobial Studies

Different novel isoxazolines were synthesized by the cyclization of secondary amino derivatives with pyridazine as a substituted intermediate in the presence of hydroxylamine hydrochloride. Isoxazoline is an important class of nitrogen and oxygen-containing five-membered heterocyclic compounds having great medicinal importance. Many heterocyclic, pharmaceutically active compounds have been synthesized using it as an intermediate. Due to this activity, it is found useful in the treatment of anti-fungal, anti-bacterial, anti-cancer, anti-amoebic, and anti-inflammatory agents. The structures of the isoxazoline derivatives were confirmed by spectral analysis. The synthesized isoxazoline shows moderate activity against bacteria and fungus.

Synthesis, Characterization and Antimicrobial Activity of Isoxazoline Derivatives

In present study isoxazoline derivatives were synthesized and antimicrobial activity of different derivatives were checked with various microbial stain. Various intermediates was synthesized and characterized in between time to time by chromatography using TLC. An isoxazoline series of compounds were synthesized by condensation reaction of phenyl ethyl acetate with substituted benzaldehyde in presence of alcoholic sodium hydroxide to get intermediate phenethyl cinnamate (chalcones), which were further treated with hydroxylamine hydrochloride in presence of sodium hydroxide to get isoxazoline derivatives. The synthesized compounds were characterized on the basis of their spectral (IR) data and evaluated for the antimicrobial activity by using Zone of Inhibition by cup plate method.

MICROWAVE ASSISTED SOLVENT FREE SYNTHESIS AND EVALUATION OF ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES OF SOME NOVEL 3, 4-BIS (SUBSTITUTED PHENYL)-7-(6-METHYL PYRIDIN-2-YL)-3, 3A, 3B, 4-TETRAHYDRO7H-PYRROLO [2, 3-C : 5,4-C']DIISOXAZOLE

Novel heterocyclic compounds were synthesized, characterized and screened for antimicrobial activity and antioxidant activity. This series of novel bis-isoxazole derivatives were synthesized via reaction of bis chalcone of succinimide treated with hydroxyl amine hydrochloride in presence of neutral alumina by microwave assisted solvent free method in good yield. It was observed that microwave assisted method produced a greater yield of products in shorter reaction times. The structures of synthesized compounds were characterized by their spectral analyses (elemental analysis, FTIR, 1H NMR) and the purity of synthesized compounds were confirmed by TLC. All the synthesized compounds were evaluated for antimicrobial activity against gram positive bacteria Staphylococcus aureus (NCIM 2079) and gram negative bacteria Escherichia coli (NCIM 2109) using DMSO solvent and antifungal activity against fungal strain Aspergillus Niger (NCIM 545). Most of the synthesized compounds exhibited a moderate grade of anti-microbial activity. The study concluded that the compound 4c exhibited potent anti-bacterial activity when compared to Chloramphenicol as standard drug while compound 4b, 4c, 5b, 5c, 5e exhibited significant anti-fungal activity when compared to Amphotericin B as standard drug. All the synthesized compounds were screened for their antioxidant activities. Among them, compounds 4a, 4e, 5a, 5b, 5c and 5e showed moderate to good antioxidant activity when compared to ascorbic acid as standard drug.

One‐step synthesis of novel N1‐substituted benzimidazole derivatives: Experimental and theoretical investigations

AbstractIn this work, we describe a simple and efficient route for the synthesis of novel N1‐substituted benzimidazole derivatives (8–14) by a rearrangement reaction of N1‐alkyl‐1,5‐benzodiazepine‐2‐thiones (1–7) in the presence of hydroxylamine hydrochloride in boiling ethanol. Good to excellent yields were achieved for a wide range of alkyl partners with both short‐chain and long‐chain substituents. The title products were identified using 1H and 13C‐NMR spectroscopic measurements and confirmed by single‐crystal X‐ray diffraction techniques for 8–10. In addition, we performed theoretical studies of 8–10 using Hirshfeld surface analysis, molecular docking studies and, along with experimental data. The predicted spectral data were obtained using density functional theory (DFT) at the B3LYP/6‐311++G(d,p) level of theory. Also, according to Monte Carlo simulations, the inhibition trend is 10 > 8 > 9 toward all metals in an acidic environment. Good inhibition performance is predicted for iron as compared to copper and aluminum metals.

Synthesis, characterization and antimicrobial activity of some new isoxazole derivatives

A series of isoxazole derivatives, 3-aryl-5-[5-(4-nitrophenyl)-2-furyl]-2,3-dihydroisoxazoles (5a-j) were synthesized by cyclocondensation reaction between 1-aryl-3-[5-(4-nitrophenyl)-2-furyl]prop-2-en-1-ones (4a-j) and hydroxylamine hydrochloride in presence of sodium acetate in glacial acetic acid at reflux temperature. Formerly, compounds (4a-j) were synthesized by the condensation of 5-(4-nitrophenyl) furan-2-carbaldehyde (3) with various aromatic ketones by using alkali as catalyst. The structures of the synthesized various isoxazole have been characterized by using elemental analysis, Infrared,1H-NMR spectroscopy and further supported by Mass spectroscopy. All the products have been screened for their in-vitro biological assay like antibacterial activity towards Gram-positive and Gram-negative bacterial strains and antifungal activity towards Aspergillus niger at a concentration of 40 µg/ml. It was exposed that the compounds 5a, 5c, 5e, 5f, and 5i showed inspiring antibacterial and antifungal activity compared to the used reference standard.

Synthesis, biological activities of chalcones and novel 4-acetylpyridine oximes, molecular docking of the synthesized products as acetylcholinesterase ligands

Heterocyclic chalcones were synthesized by reaction of 4-acetylpyridine with the corresponding aromatic aldehydes under Claisen Schmidt conditions. These chalcones were used as starting material for the synthesis of oximes in the presence of hydroxylamine hydrochloride. The structures of the synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and ESI-MS, HRMS spectral analyses. All the synthesized compounds were evaluated for their antioxidant activity by DPPH• method and their in vitro antimicrobial activity by disk diffusion method against two Gram-negative bacteria, one Gram-positive bacteria and two fungal strains (C. albicans and A. niger). The results showed that the synthesized compounds did not display significant antioxidant activity. However, compounds 3b, 3d, 3f, 3h, 3i showed excellent antibacterial activity better than the standard drug against the bacterial strain S. aureus (ATCC 25923). The two compounds 3c, 3d proved very active against the fungal strain A. niger (MIC= 7.81 µg/ mL, 15.62 µg/mL respectively) while the antifungal drug used as reference (Fluconazole) was inactive. Molecular docking and molecular dynamics results revealed that the synthesized compounds, 4e, 4c, and 5j, were involved in a large number of favorable interactions with the active site residues of the acetylcholinesterase protein, which can stabilize the ligands in the active site and increase their affinities.

Ultrasound-assisted one-pot three-component synthesis of new isoxazolines bearing sulfonamides and their evaluation against hematological malignancies

In the present study, following a one-pot two-step protocol, we have synthesized novel sulfonamides-isoxazolines hybrids (3a-r) via a highly regioselective 1,3-dipolar cycloaddition. The present methodology capitalized on trichloroisocyanuric acid (TCCA) as a safe and ecological oxidant and chlorinating agent for the in-situ conversion of aldehydes to nitrile oxides in the presence of hydroxylamine hydrochloride, under ultrasound activation. These nitrile oxides could be engaged in 1,3-dipolar cycloaddition reactions with various alkene to afford the targeted sulfonamides-isoxazolines hybrids (3a-r). The latter were assessed for their antineoplastic activity against model leukemia cell lines (Chronic Myeloid Leukemia, K562 and Promyelocytic Leukemia, HL-60).

Benzofuran-oxadiazole hybrids: Design, Synthesis and antimicrobial activity studies

The six benzofuran-oxadiazole derivatives (4a-d) and (5a-b) have been designed, synthesized, characterized and evaluated for antimicrobial activity. The key synthetic intermediate 5-bromo-N'-hydroxybenzofuran -2-carboxamidine (3) was prepared from 5-bromobenzofuran-2-carboxylic acid (1) in two consecutive steps involving reaction with NaN3, in presence of TEA, Xtalfluor-E, PPh3 in dry DCM at 0oC followed by the treatment of resulting carbonitrile (2) with hydroxylamine hydrochloride in presence of sodium methoxide under reflux in aqueous ethanol. Reaction of carboxamidine (3) with different aryl esters in presence of K2CO3 under reflux conditions in toluene afforded 3-(5-bromobenzofuran-2-yl)-5-substituted phenyl-1,2,4-oxadiazoles (4a-d) while the refluxion of a solution of carboxamidine (3) in dichloromethane with chloro/bromo acetyl chloride in presence of TEA and a catalytic amount of HBTU furnished 3-(5-bromobenzofuran-2-yl)-5-(chloromethyl)-1,2,4-oxadia zole (5a) and 3-(5-bromobenzofuran-2-yl)-5-(bromomethyl)-1,2,4-oxadiazole (5b).

Synthesis of Acrylonitrile Based High Internal Phase Emulsion Monoliths and their Application in Recovery of Heavy Metal Ions

Polymeric monoliths based on acrylonitrile-divinyl benzene were synthesized successfully by high internal phase emulsion (HIPE) polymerization. Highly porous polyHIPEs were prepared by variation in oil to water ratio as well as type and concentration of porogens. The porogens evaluated were toluene, chlorobenzene, heptane and chloroform. The effect of oil to water ratio and porogen type and concentrations on morphology and surface area of polyHIPEs were investigated. The polyHIPEs were modified to amidoxime functionality by treating base catalyzed reaction with hydroxylamine hydrochloride in presence of base. The treated and modified polymeric monoliths were characterized by FT-IR, SEM and surface area analysis. The modified porous polyHIPEs were tested for adsorption of Cr(VI) metal ions at various pH.

Synthesis and Biological Evaluation of Some Novel Mannich Bases of Isoxazoline Derivatives as Possible Antimicrobial Agents

Novel isoxazoline derivatives were synthesized by condensation of substituted acetophenones with aldehyde in presence of alcoholic NaOH to get intermediate chalcones, which were further treated with hydroxylamine hydrochloride in presence of sodium hydroxide to get isoxazoline derivatives. The latter were refluxed separately with isonicotinic acid hydrazide and sulphanilamide in presence of formaldehyde for 6-10 h to afford corresponding Mannich bases. The structures of synthesized compounds were established on the basis of melting point, TLC, IR, 1H NMR and HRMS. Antimycobacterial activity of compounds (3a-j) were assessed against M. tuberculosis (vaccine strain, H37 Rv strain) ATCC27294 using microplate Alamar Blue assay (MABA). Further the derivatives were evaluated for the antibacterial activity against Gram positive bacteria S. aureus (ATCC 9144), S. epidemidis (ATCC12228) and Gram negative bacteria E. coli (ATCC 25922), Klebsiella (ATCC 4352), while antifungal activity against A. flavus (ATCC 9643) and A. niger (ATCC 16404) by using agar well diffusion method using ciprofloxacin and fluconazole as standards, respectively. The results of antimicrobial studies showed that some of the derivatives posses mild to moderate biological activity as compared to standard.

Amidation of aldehydes using mono-cationic half-sandwich rhodium(III) complexes with functionalized phenylhydrazone ligands

A series of mono-cationic half-sandwich rhodium(III) complexes have been synthesized in methanol using phenylhydrazone-derived ligands (L1–L6) and the starting precursor [(η5-C5Me5)2Rh2(μ-Cl)2Cl2] in a 2:1 molar ratio. The N,N′-phenylhydrazone complexes have been isolated as tetraphenylborate salts. All complexes were characterized by elemental analysis, FT-IR, UV–visible, NMR spectroscopy and mass spectrometry. The molecular structure of complex [(η5-C5Me5)Rh(L1)Cl](BPh4) (1) was confirmed by single-crystal X-ray structure analysis. Complex [(η5-C5Me5)Rh(L3)Cl](BPh4) (3) was used as an efficient catalyst for the amide formation reaction, with up to 99% conversion after 2 h in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate.

Simultaneous determination of different ruthenium species by rate differential kinetic spectrophotometry

With increasing nuclear fuel burning up, the yield of fission products increases and the reaction of high-yield fission products comparatively stands out. The precious metal ruthenium is one of the main fission products and a very important indicator in reprocessing and recovery, but the removal of this metal in the first co-decontamination step of plutonium uranium recovery by extraction is difficult. To rapidly determine the ruthenium concentrations in a uranium purification cycle and radioactive waste treatment processes, a simple and sensitive differential kinetic spectrophotometry that allows the simultaneous determination of ruthenium and nitrosyl ruthenium in a complex system is proposed. Based on the determination of the initial apparent rate constant, the reaction order in terms of the Ru3+ and [Ru(NO)]3+ concentrations, the equilibrium constant for the reaction of bipyridyl with Ru3+ and [Ru(NO)]3+ in the presence of hydroxylamine hydrochloride, and the measurement of the initial formation rate and equilibrium concentration of products [Ru(bipy)3]2+, Ru3+, and [Ru(NO)]3+ in the complex system were analyzed using mathematical models, obtaining satisfactory results. The recovery rates ranged from 95.5% to 105%, and the relative standard deviations ranged from 2.9% to 4.3%.

Spectrophotometric Determination of Sulfamethoxazole Based on Charge-Transfer Complexation with Sodium Nitroprusside

A simple, accurate and precise spectrophotometric method has been developed for the analysis of sulfamethoxazole (SMZ) in pure form and pharmaceutical preparation. The method involves a direct charge transfer complexation of sulfamethoxazole (SMZ) with sodium nitroprusside (SNP) in alkaline medium and the presence of hydroxyl amine hydrochloride. Variables affecting the formation of the formed orange colored complex were optimized following two approaches univariate and central composite experimental design (CCD) multivariate. Under optimum recommended conditions, the formed complex exhibits λmax at 512 nm and the method conforms Beer's law for SMZ concentration in the range of 5.0-150.0 (µg.mL-1) with molar absorptivity 1.139×103 L.mol-1.cm-1, and r = 0.9997. Analysis of SMZ pharmaceutical dosages shows a good agreement with the real amounts.

Development of Spectrophotometric Method for the Determination of Azoxystrobin Fungicide after Derivatization

A UV-Visible spectrophotometric method has been developed for the determination of azoxystrobin fungicide. Complexation reaction of the azoxystrobin fungicide was carried out with the Ferric (III) chloride in presence of hydroxylamine hydrochloride in alkaline medium resulting in a reddish-brown color complex. The absorbance of the complex was measured at 513 nm using UV-visible spectrophotometer. Different parameters affecting the derivatization reactions were carefully studied and optimized. Beer’s law was obeyed in the concentration range of 1-12 μg mL-1. The molar absorptivity, limit of detection and limit of quantification were calculated and found to be 4.3 × 10-4 L mol-1 cm-1, 0.38 μg mL-1 and 1.26 μg mL-1 respectively. Similarly, the mean limit of detection and limit of quantification were calculated for residue determination and were found to be 3.8 ± 1.02 μg mL-1 and 3.98 ± 1.4 μg mL-1, respectively. The proposed method was successfully applied for the determination of azoxystrobin in pure form and in commercial formulations.