Hydroxylamine Hydrochloride Research Articles

Regioselective Synthesis of 3,4-Disubstituted Isoxazoles by Using a Chalcone-Rearrangement Strategy

AbstractWe have developed a regioselective synthesis of 3,4-disubstituted isoxazoles by using a chalcone-rearrangement strategy. The reaction of β-ketoacetals with hydroxylamine hydrochloride and pyridine afforded the corresponding 3,4-disubstituted isoxazoles via isoxazolines or oximes. Depending on the substrate, another disubstituted isomer was also obtained under our optimized conditions, and a reaction mechanism for each transformation is proposed.

Continuous-flow Heck coupling reactions catalyzed by Pd complexes of amidoxime fibers

Improving production efficiency and developing green catalytic systems are key issues for applying Heck coupling reactions in the chemical industry. In this study, an amidoxime-fiber-supported Pd catalyst is prepared from polyacrylonitrile fiber, hydroxylamine hydrochloride, and PdCl2. The morphology and structure of amidoxime-fiber-supported Pd are characterized by scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectrometer, X-ray diffraction, and inductively coupled plasma-optical emission spectrometer. A packed-bed flow reactor is designed and employed for catalysis of the Heck reaction of iodobenzene and styrene based on the amidoxime-fiber-supported Pd catalyst. The effects of reaction temperature, flow rate, cycle time, and reactant concentration on the conversion and yield are investigated. The results show that the optimal conditions for the continuous-flow single reactor are 70 °C, iodobenzene concentration of 30 mmol L−1 in a solution of N,N-dimethylformamide (100 mL) under continuous flow at a flow rate of 2 mL min−1. The catalyst showed good activity and stability after a continuous operation time of 50 h, with catalytic activity 2.21 times higher than that obtained with traditional batch reaction. Furthermore, we have established a new flow reaction system based on the numbering-up of reactors with a parallel connection. The catalytic efficiency of four parallel reactors is four times higher than that of a single reactor. Kinetic studies reveal that the reaction has low activation energy (8.8771 kJ mol−1), indicating that amidoxime-fiber-supported Pd has good catalytic activity. This research provides an alternative pathway for highly efficient Heck coupling in continuous flow.

Synthesis, characterization and computational studies of new naphthoquinones fused isoxazoles by the regiospecific tandem sonogashira-cyclization reaction

The fast methodology of tandem Sonogashira-cyclisation reaction of 2-iodo-3‑methoxy-1,4-naphthoquinone with a series of alkynes followed by the addition of hydroxylamine hydrochloride provided a small library of seven novel 1,4-naphthoquinones fused with regiospecific NO isoxazole with moderate yield, up to 62%. The characterization by nuclear magnetic resonance (1H and 13C NMR), gas chromatography-mass spectrometry (GC-MS), and high-resolution electrospray ionization mass spectrometry (ESI-HRMS) was carried out with these seven compounds. The computational analyses were done by density functional theory (DFT) using B3LYP/6–311G* and the geometrical properties, the molecular electrostatic potential (MEP), the frontier molecular orbitals (FMO), and some global parameters were examined for the seven final compounds, the seven intermediaries of the reaction proposed in this study and the seven isomers ON of the isoxazole fused with the 1,4-naphthoquinone. The comparisons of the calculated parameters between the isomers ON and NO demonstrated the superior stability of the isomer NO and their higher tendency of polarizable that support the importance of the study and the potential to have biological activity.

A Green and Ecofriendly Catalytic System for One-Pot Three-Component Synthesis of 5-Substituted 1H-Tetrazoles Under Microwave Irradiation

In this research work, the high-yielding and simple synthesis of 5-substituted 1H-tetrazoles derivatives through the one-pot three-component reaction of aldehydes, hydroxylamine hydrochloride and sodium azide catalyzed by MNPs-Picolylamine-Cu(OAc)2 nanocomposite in water under microwave irradiation has been reported. The MNPs-Picolylamine-Cu(OAc)2 nanocomposite is successfully fabricated through the immobilization of copper (II) acetate stabilized on magnetic Fe3O4 nanoparticles modified with Picolylamine [MNPs-Picolylamine-Cu(OAc)2] and then is well analyzed by various techniques such as FT-IR, XRD, TGA, SEM, TEM, EDS, VSM and ICP-OES. At the end of the reaction, the MNPs-Picolylamine-Cu(OAc)2 catalyst can be easily recycled and reused and the products obtained had high efficiency and purity.

(E)-1-(5-Methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one Oxime

The reaction of 1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (1) with excess hydroxylamine hydrochloride (2 mole equivalents) in dry ethanol afforded (E)-1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one oxime (2) in 86% yield. The structure of the new heterocycle 2 was confirmed using nuclear magnetic resonance spectroscopy, single crystal X-ray and elemental analysis.

Ring transformation reactions of 4-hydroxy-3-nitro-6-phenyl-6H-pyrano[3,2-c]quinoline-2,5-dione and antioxidant activity

4-Hydroxy-3-nitro-6-phenyl-6H-pyrano[3,2-c]quinoline-2,5-dione was reacted with some 1,2-binucleophiles, such as hydrazine, phenylhydrazine, and hydroxylamine hydrochloride affording the interesting pyrazolyl and isoxazolylquinolinones. Nucleophilic reactions of 3-nitropyranoquinolinone with different 1,4-binucleophiles, leading to a variety of novel diazepinyl, oxazepinyl, and thiadiazepinylquinolinone derivatives, were described. The structure of compounds was proved by elemental analysis and spectral data. Selected products were screened for their antioxidant activity and showed higher radical scavenging abilities.

Mass Spectrometry-Based Atlas of Extracellular Matrix Proteins across 25 Mouse Organs.

The extracellular matrix (ECM) is a critical non-cellular component of multicellular organisms containing a variety of proteins, glycoproteins, and proteoglycans which have been implicated in a wide variety of essential biological processes, including development, wound healing, and aging. Due to low solubility, many ECM proteins have been underrepresented in previous proteomic datasets. Using an optimized three-step decellularization and ECM extraction method involving chaotrope extraction and digestion via hydroxylamine hydrochloride, we have generated coverage of the matrisome across 25 organs. We observe that the top 100 most abundant proteins from the ECM fractions of all tissues are generally present in all tissues, indicating that tissue matrices are principally composed of a shared set of ECM proteins. However, these proteins vary up to 4000-fold between tissues, resulting in highly unique matrix profiles even with the same primary set of proteins. A data reduction approach was used to reveal related networks of expressed ECM proteins across varying tissues, including basement membrane and collagen subtypes.

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 6-substituted-3-formyl chromone derivatives as anti-leishmanial agents and their possible mechanism of action in Leishmania donovani

Eleven new compounds, including the hydrazones 4a-h, pyrazole 5, and pyrazole-oximes 7b-c, were synthesized by condensation reaction between 6-substituted (-H, -Me, -F) 3-formylchromones 1a-c with N-substituted hydrazines 2a-d and hydroxylamine hydrochloride 3. The synthesized compounds were evaluated for their in vitro antileishmanial activity to determine the IC50 values. Compounds 4b, 4c and 4e exhibited the strongest antileishmanial activity with IC50 values between 1.6 – 4.7 µm. A plausible mechanism of action is proposed for the antileishmanial activity of the above-mentioned compounds. We also studied the effect of these three compounds on macrophages, which represent the mammalian host-cell. The results obtained on this system were about one order of magnitude larger when compared to those of L. donovani, thus supporting these compounds potential as precursors of antileishmanial drugs.

Efficient Synthesis of 4-Arylmethylene-3-methylisoxazol-5(4H)-one Derivatives Catalyzed by Malic Acid

Abstract:The efficient, straightforward, and green procedure was established in the direction of synthesis of 4-arylmethylene-3-methylisoxazol-5(4H)-one derivatives using the malic acid, which acted as the catalyst for the three-component heterocyclization reaction. In this reaction, aryl/heteroaryl aldehydes, hydroxylamine hydrochloride, and ethyl acetoacetate/ethyl benzoylacetate were applied as the reactants. The reaction was optimized to attain the best conditions for the synthesis of target heterocyclic compounds in a single step route. The best results were obtained from optimization experiments using 10 mol% malic acid as the catalyst, water solvent, and 50ºC temperature. The noticeable features of this process are the simplicity of the experimental procedure, the easy separation of the pure compounds from the product mixture, the simplicity of operation, avoidance of any hazardous organic solvents, no use of chromatographic purification techniques, clean reaction profiles, high yields, relatively short reaction time, and eco-friendliness

Spectrophotometric Assay for the Determination of Phenylephrine-HCl using Sodium Nitroprusside and Hydroxylamine Hydrochloride as a reagents

This study addressed a straightforward, precise and easy spectrophotometric method to determine phenylephrine hydrochloride (PHP) in bulk and pharmaceuticals dosage (drops and syrup). This method involves the interaction of sodium nitroprusside (SNP) with phenylephrine hydrochloride and hydroxylamine hydrochloride (HAH) in a phosphate buffer solution (pH 12) to produce a green color product. The overlain spectra of the product showed maximum PHP absorption at 714nm. The absorbance was started to increase linearly with the increased concentration of PHP. Under the optimal conditions, Beer’s law has been obeyed within the concentration range 0.2 – 8µg/mL. The developed method has good accuracy (average recovery) of 101.04% and precision (RSD) is less than 1.2%. with molar absorptivity 4.4610x104 L.mol-1.cm-1. The detection limit (LOD) and limit of quantification limit (LOQ) were 0.047 and 0.155ng/mL respectively. The suggested approach was applied practically to the determination of PHP in drug products (drops and syrup) with good precision and sensitivity. In addition, the validity of the suggested procedure was confirmed by the standard addition method. The advanced spectrophotometric procedure for assay of PHP is precise, simple, and reproducible with inexpensive and quite safe solvents. It could be applied in principles and practice for routine work analysis of PHP in bulk and pharmaceutical dosages.

Synthesis, Spectroscopic Study of new Substituted heterocyclic compounds derived from Molononitrile and Cytotoxic agents against MCF-7 Human Cancer Cells

In the present work , 4-((dicyanomethyl)diazenyl)-N-(5-methylisoxazol-3-yl)benzene sulfonamide E and 2,2'-(1E,1E')-(sulfonylbis(4,1-phenylene))bis(diazene-2,1-diyl) dimalononitrile C were synthesized from the reaction of Sulfamethaxazole and Dapsone with Malononitrile and condensed with 2,4dinitophenyl hydrazine derivatives to produce 3,5diaminopyrazole derivatives E1 and C1.condensation with hydroxyl amine hydrochloride produce isoxazole derivative E2,C2 .Treatment of E and C with urea and thiourea yielded the pyrimidine derivatives E3-E4,C3-C4 and treatment with secondary amine afforded piperazine derivatives E5,C5. While its condensation with thiosemicarbazide yielded the derivatives E6, C6. The structure of the newly synthesized compound were established on the basis of physical data and spectral methods such as IR, 1H-NMR ,13C-NMR and Mass spectra. Cytotoic evaluation of four compounds, against MCF-7 (human breast adeno carcinoma) cell lines.

Synthesis and Characterization of Mixed Ligand Complexes of Co(II) And Ni(II) with Hippuric Acid, Ammonium Thiocyanate and Hydroxyl Ammonium Chloride

Synthesis and Characterization of Mixed Ligand Complexes of Co(II) And Ni(II) with Hippuric Acid, Ammonium Thiocyanate and Hydroxyl Ammonium Chloride

Synthesis and Reactions of Some Novel 4H-3,1-Benzoxazinone Bearing Chalcone Moiety with Antibacterial Evaluation

2-[3-(4-Methoxy-3-methylphenyl)-3-oxoprop-1-enyl]-4H-3,1-benzoxazin-4-one 2 was synthesized by the cyclization of the respective N-acylanthranilc acid 1. The bromination of benzoxazinone 2 afforded the dibromo anthranilic acid 3, which gave N-pyrazolyl anthranilic acid 4 on treatment with hydrazine. The ethanolysis of benzoxazinone 2 with sodium ethoxide gave ethyl anthranilate derivative 5 which on treatment with amines furnished the corresponding ethyl N-substitutedanthranilate 6a-b. The aminolysis of benzoxazinone 2 with ammonium acetate, primary amines and/ or secondary amines afforded the corresponding amides 7a-c and 8a-b. The treatment of benzoxazinone 2 with 2-aminophenol and/ or o-phenylendiamine gave the corresponding 3-(benzooxazol-2-yl) propenone 9 and 3-(benzimidazol-2-yl) propenone 10, respectively. 3-Thiourido-3(4H)-quinazolinone derivative 11 was obtained on the treatment of benzoxazinone 2 with thiosemicarbazide. The reaction of the benzoxazinone 2 with hydroxylamine hydrochloride furnished the corresponding 3-hydroxy-2-isooxazoline-5-yl-4(3H)-quinazolinone 12. The synthesized compounds were screened against strains of bacteria and showed mild to moderate activity towards both gram-positive bacteria and gram-negative bacteria.

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.

Selective micro extraction of rare earth elements and yittrium in rock samples using silica modified with xylenol orange and their determination by ICP-AES

A systematic study on the selective extraction of rare earth elements (REEs) and yttrium onto silica modified with xylenol orange (SMXO) was carried out and a scheme for the pre-concentration and separation of REEs and Y in rock samples is discussed. A simple single step preparation of silica and its modification by xylenol orange in presence of cetyltri-methylammonium bromide is enumerated. Characterisation of prepared adsorbent was carried out by surface area analysis, IR data and SEM data. REEs and Y were adsorbed onto SMXO at pH ≥ 3 and after a contact period of 30 minutes. Adsorbed REEs and Y were eluted from SMXO with 0.5% (w/v) EDTA solution. Aluminium and iron when present above 200 mg/L were interfering in the analysis of REEs. Aluminium interference was eliminated by removing it as sodium aluminate in the fusion stage of rock samples. Interference of Fe3+was avoided by reducing Fe (III) to Fe (II) using hydroxylamine hydrochloride. Separated REEs were determined by ICP-AES. The proposed method is simple, accurate and the precision is characterized by the % RSD ranges from 2.0-5.1% at the determination limit ranging from 0.2-5µg/mL.

Degradation of bisphenol A in Fe-doped layered double hydroxide activated persulfate systems by enhancing with hydroxylamine hydrochloride

Degradation of bisphenol A in Fe-doped layered double hydroxide activated persulfate systems by enhancing with hydroxylamine hydrochloride

Transition metal-free and temperature dependent one-pot access to phenanthrene-fused heterocycles via a 1,3-dipolar cycloaddition pathway.

A versatile, operationally simple, temperature-dependent, and transition metal-free one-pot protocol has been devised for the preparation of novel phenanthrene-fused pyrazoles. Notably, the overall process involved an intermolecular condensation, an intramolecular 1,3-dipolar cycloaddition, and an aromatization sequence starting from biaryl-2,2'-aldehydes bearing enoate esters with various hydrazine hydrochlorides. Notably, the sequential one-pot three-component operation has also been achieved. Importantly, it was also shown that this protocol was amenable to hydroxylamine hydrochloride as the nitrogen source and furnished phenanthrene-fused isoxazoles. Notably, the temperature dependent nature of this protocol was also demonstrated, which led to the formation of dealkoxylcarbonylated phenanthrene-fused pyrazoles at slightly higher temperatures and longer reaction times. Remarkably, this metal-free protocol effectively constructed two C-N bonds and one C-C bond and exhibited a broad substrate scope.

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.

Molecular mechanism of the transformation of oxidized lignin to N-substituted aromatics.

The cleavage of C-C bonds in oxidized lignin model compounds is a highly effective methodology for achieving lignin depolymerization, as well the generation of N-substituted aromatics. Here, density functional theory calculations were performed to understand the mechanism of the transformation of an oxidized lignin model compound (ligninox) and hydroxylamine hydrochloride to N-substituted aromatics. The reaction was proposed to proceed via an energetically viable mechanism featuring the initial production of HOAc acting as proton bridge. According to our calculations, Z-type oxime is the major intermediate of the reaction, with an energy barrier of 22.9 kcal mol-1, owing to the weak interactions between methoxy and oximino groups being stronger than that of E-type oxime. Additionally, the hydroxy addition is the rate-determining step, with an energy barrier of 27.0 kcal mol-1. Moreover, the huge net energy change of Beckmann and abnormal Beckmann rearrangements is the main overall thermodynamic driving force for producing N-substituted aromatics from oximes. The theoretical results have provided a clear picture of how ligninox transforms into N-substituted aromatics and are expected to provide valuable theoretical guidance for lignin depolymerization.