Presence Of Sodium Nitrite Research Articles

Synthesis of nitroanilines catalyzed by horseradish peroxidase in the presence of NaNO2 and H2O2

The synthesis of nitroanilines catalyzed by horseradish peroxidase(HRP) in the presence of sodium nitrite and hydrogen peroxide was investigated. o-Nitroaniline and p-nitroaniline were found in the nitrated products. 2-Aminotoluene and 4-aminotoluene could also be nitrated to give corresponding nitrated products. This protocol has great potentials to open new avenues useful for the synthesis of nitroaniline and its derivatives.

Synthesis, Characterization and Testing of Biological Activity of Some Novel Chalcones Derivatives of Coumarin

In the present communication, we herein report the synthesis of some novel derivatives of coumarin i.e. 3-((2E)-(3-(2-hydroxy-5-((aryl)diazenyl)phenyl)acryloyl)-2H-chromen-2-one (2a-2g). Various aromatic amines and salicylaldehyde in the presence of sodium nitrite and conc. HCl yielded 2-hydroxy-5-((aryl)diazenyl)benzaldehyde (1a-1g). A series of 3-((2E)-(3-(2-hydroxy-5-((aryl)diazenyl) phenyl)acryloyl)-2H-chromen-2-one were synthesized by the reaction of 2-hydroxy-5-((aryl)diazenyl) benzaldehyde and coumarin in presence of ethanol and piperidine. Different analytical techniques such as elemental analysis, IR spectra, H NMR spectra and mass spectra were used to elucidate the structures of all newly synthesized compounds (1a-1g and 2a-2g). The anti-bacterial and anti-fungal activity of newly synthesized chalcone derivatives (2a-2g) were evaluated against different bacterial and fungal stains. Some of these compounds showed promising activity against different stains.

P8: Dietary nitrite induces TFF3 and attenuates inflammation in experimental colitis

Nitric oxide (NO) and its derivative nitrite NO 2 - have evolved as important mediators in the prevention of gastrointestinal diseases. A central event in inflammatory bowel disease is the disruption of the mucosal homeostasis. Trefoil peptides (TFFs) are emerging as key mediators in the defense and repair of the gastrointestinal mucosa as they play a key role in epithelial restitution, the initial step in the wound healing process. Here we examined the anti-inflammatory effects of dietary NO 2 - and the potential role of TFFs in a model of ulcerative colitis: the dextran sulfate sodium (DSS) model. Balb/c mice were treated with DSS (2%, drinking water) in the presence of sodium nitrite (1 mg/kg, drinking water), or with 2.5% DSS for 3 days prior to administration of sodium nitrite. At the end of the experiment (7–10 days) the extent of inflammation was measured by the colon length, the disease activity index (DAI), and colonic expression of the intestinal trefoil factor (TFF3). In addition, colon epithelial cells (SW480) were treated with increasing doses of Na NO 2 - (1μM-1 mM), and the mRNA levels of TFF3 were evaluated. Finally, the effect of Na NO 2 - (1 μM−1 mM) was also analyzed in an in vitro wound healing assay (SW480 cells, 0–48 h). DSS groups (2% and 2.5%) developed colitis as evident by a marked reduction in colon length as well as an increase in DAI, compared to the control groups. In both groups nitrite reduced DAI score but the prevention of the decrease in colon length was only significant with 2% of DSS. The colonic levels of TFF3 increased in the presence of 2% DSS but decreased with 2.5% DSS administration. NO 2 - treatment increased TFF3 levels in both groups, but the effect was higher with 2% DSS. A dose-dependent response in mRNA expression of TFF3 was observed in SW480 cells after NO 2 - treatment; where a maximum increase in the expression was reached with 1–10 μM of nitrite. Interestingly, these results mirrored those obtained in the epithelial wound healing model in which nitrite increased the speed of repair. In conclusion, our results show that the dietary administration of nitrite reduces inflammation and improves clinical symptoms in DSS-induced colitis. This protection may involve regulation of the epithelial restitution process, as indicated by the increase in the healing process and the expression of TFF3 by dietary concentrations of nitrite. Disclosure Nothing to disclose.

Halogenation and DNA cleavage via thermally stable arenediazonium camphorsulfonate salts

A series of stable arenediazonium camphorsulfonate salts (2a–2j) were synthesized by simple diazotization of several aromatic amines in the presence of sodium nitrite and camphorsulfonic acid. All the new arenediazonium camphorsulfonates, which were characterized by multinuclear (1H and 13C) NMR, IR, DSC, and X-ray diffraction analysis (2e and 2f) provide unambiguous proof for the molecular structures of 2e and 2f. The efficient application of these salts in halogenation reactions was studied in solvent and solvent-free conditions and the DNA cleavage activity was also assessed. These arenediazonium camphorsulfonate salts are noticed as efficient DNA cleaving agents.

Synthesis of a magnetoactive compound based on iron(II) sulfate

The effect of synthesis parameters on properties of a magnetoactive compound (MAC) prepared via condensation of iron(II) sulfate in the presence of sodium nitrite is investigated. It is found that nitrite ions almost completely coprecipitate with the solid phase during the formation of a magnetoactive compound and subsequently participate in the redox conversions to yield magnetite. In order to obtain a magnetoactive compound with high relative magnetic susceptibility, condensation from the initial solutions is to be carried out at least 15 min after it is prepared; sodium nitrite consumption is to be at least 0.12 mol/mol FeSO4.

Determination of Meloxicam in Pharmaceutical Formulation byAzo-Coupling Reaction with Sulphanilic Acid Using Both Batch and Flow- Injection Technique

Two sensitive and fast spectrophotometric methods were used by batch and flow-injection spectrophotometric techniques for the determination of meloxicam are proposed. The methods were based on azo-coupling reaction of meloxicam with sulphanilic acid in the presence of sodium nitrite in alkaline medium after converted to primary aromatic amine. The calibration curves resulting from measuring the absorbance at 365 nm are linear over the ranges 1.0-20 and 3.0-30µg/ml with detection limits of 0.5 and 1.0µg/ml, respectively. The molar absorptivity and Sandell index were 1.3839×104l/mol.cm and 2.539×10-2µg/cm2 respectively. The methods are applied to the routine analysis of meloxicam in pharmaceutical formulations.

Design, synthesis and reactivity with dichloro-bis(triphenylphosphine) platinum(II) of two triazenide compounds

In the presence of sodium nitrite, the reaction of methyl anthranilate and 2-aminopyridine or o-aminobenzoic acid gives two triazenes, 1-[(2-carboxymethyl)benzene]-3-[2-pyridine]triazene (HL) and 1-[(2-carboxymethyl)benzene]-3-[o-aminobenzoic acid]triazene (H 2L′), respectively. In the presence of Et 3N, the reaction of Pt(PPh 3) 2Cl 2 and HL or H 2L′ produces two triazenido platinum(II) complexes, Pt(PPh 3) 2(L)Cl ( 1) and Pt(PPh 3) 2(L′) (2), respectively, which have been characterized by X-ray crystallography, 31P NMR spectra, UV–Vis spectra, emission spectra and cyclic voltammetry. When excited at 310 nm, complexes 1 and 2 show luminescence at 432 and 442 nm, respectively, which is consistent with the trend of the lowest-energy absorption wavelengths of 1 (376 nm) and 2 (379 nm). Complexes 1 and 2 exhibit one or two redox waves and follow the order 1 (0.97 V) → 2 (0.89 and 0.07 V), which is also in accordance with the trend of the lowest-energy absorption spectra of 1 (376 nm) and 2 (379 nm).

Role of Glycogen in Processes of Cerebellar Glial Cells under Conditions of Its Damage with Sodium Nitrite

Ultrastructure of processes of glial cell, astrocytes of the molecular layer of cerebellar cortex in Rana temporaria frog, under conditions of damage to the cerebellum caused by NO-generating compound sodium nitrite was studied under an electron microscope. It was found that astrocytes have at least two types of processes: the first (fibrillar) primarily contained numerous fibrils and few glycogen granules and the second (granular) primarily containing glycogen granules. In the presence of NO-generating compound in toxic doses, fibrillar processes are damaged or completely degrade more rapidly than granular ones. The processes containing glycogen can protect both damaged synapses and individual synaptic buttons by forming a compact structure, wrapping, around them. We analyzed the possible role of glycogen of cerebellar glial cell processes in neuroglial interactions in the presence of sodium nitrite.

Ethyl 1-Aminotetrazole-5-carboxylate로부터 유도된 헤테로고리 화합물들의 항균 활성 시험

Ethyl 1-aminotetrazole-5-carboxylate (1)를 hydrazine hydrate와 반응시켜서 대응하는aminohydrazide 2를 합성한 후에, 화합물 2를carbon disulfide와 반응시켜서 1,3,4-oxadiazole-5-thiol structure 3을 합성하였다. 얻어진 화합물 3을 either chloroacetone 또는 ethyl chloroacetate와 반응시켜서S-acyl 1,3,4-oxadiazole 유도체인 4 와 5를 합성하였으며, 또한 hydrazine hydrate와 반응시켜서 4-amino-1,2,4-triazole-5-thiol 유도체인 6을 합성하였으며, 화합물 6을 glacial acetic acid와 반응시켜서 6-methyl-1,3,4-triazolo[3,4-b]-1,3,4-thiadiazole (7)을 합성하였다. 한편, 알려진 방법에 따라서, 화합물 1로부터 tetrazolo[5,1-f]-1,2,4-triazine 9을 얻은 다음에, 화합물 9를 carbon disulfide와 반응시켜서 8-thione 유도체인 10을 합성한 후에, 대응하는 화합물 11, 12 및 13을 합성하였다. 얻어진 화합물13을 이용하여1,2,4-triazolo[4,3-d]tetrazolo[5,1-f]-1,2,4-triazines 14와 15를 합성하였다. 새롭게 합성한 화합물들의 화학구조를 확인하였으며, 합성한 화합물들에 대한 항균 활성시험을 수행하였다. Ethyl 1-aminotetrazole-5-carboxylate (1) reacted with hydrazine hydrate to give the corresponding aminohydrazide 2. Cyclization of 2 by carbon disulfide yielded 1,3,4-oxadiazole-5-thiol structure 3. Reaction of 3 with either chloroacetone or ethyl chloroacetate furnished S-acyl 1,3,4-oxadiazole derivatives 4 and 5, respectively. Also compound 3 reacted with hydrazine hydrate afforded 4-amino-1,2,4-triazole-5-thiol derivative 6. 6-Methyl-1,3,4-triazolo[3,4-b]-1,3,4-thiadiazole structure 7 was synthesized by reaction of aminothiol 6 with glacial acetic acid. Diazotization of 1 with sodium nitrite in presence of hydrochloric acid yielding the diazonium salt which on treating with hippuric acid, oxazolone derivative 8 was obtained. Furthermore, tetrazolo[5,1-f]-1,2,4-triazine 9 was constructed via cyclization of aminoester 1 with formamide. Compound 9 reacted with carbon disulfide to furnish 8-thione derivative 10 which reacting with chloroacetone, ethyl chloroacetate, and hydrazine hydrate, the corresponding chemical structures 11, 12, and 13 were synthesized. 1,2,4-Triazolo[4,3-d]tetrazolo[5,1-f]-1,2,4-triazines 14 and 15 were resulted by treating of compound 13 with triethyl orthoformate, and glacial acetic acid, respectively. The structures of the newly synthesized products were elucidated according to elemental analyses and spectroscopic evidences. Some of the representative members of the prepared compounds were screened for antimicrobial activity.

Direct spectroscopic observation of binding of sugars to polymers having phenylboronic acids substituted with an ortho-phenylazo group

A novel vinyl monomer, 3-dimethylamino-6-( p-methacrylamidophenylazo)phenylboronic acid (AzoPBA), which had been prepared by the coupling of p-aminophenyl methacrylamide hydrochloride with m-dimethylaminophenylboronic acid in the presence of sodium nitrite, was polymerized with 3-dimethylaminopropylacrylamide (DMAPAA). The copolymer obtained (Poly(DMAPAA/AzoPBA)) bound to sugars such as fructose and glucose in a weakly alkaline region (8 < pH), which was indicated by the absorbance change of the diphenylazo group at 557 nm. In contrast with this, a copolymer of N, N-dimethylacrylamide (DMAA) and the AzoPBA (Poly(DMAA/AzoPBA)) bound to sugars in a more alkaline region (9 < pH). The larger sensitivity of the former copolymer to the sugars than the latter in a weakly alkaline region is due to the supporting effect of tertiary amino group in the DMAPAA residue to the binding of sugar to the phenylboronic acid moiety. The association constant ( K) of boronic acid residue in these copolymers with fructose was larger than that with glucose. These results indicated the usefulness of the DMAPAA/AzoPBA copolymer for the sensing of sugars in the weakly alkaline region near the physiological pH.

Bilitrienones from the chemical oxidation of dodecasubstituted porphyrins

The structure of the ring-opened product from direct oxidation of meso-tetra-arylporphyrins has been controversial for three decades. Herein we show that bilitrienones 2 are obtained from oxidation of metal-free dodecasubstituted porphyrins 1 in the presence of sodium nitrite, trifluoroacetic acid, and air oxygen. The presence of the para-nonyl groups in 1b stabilized the corresponding bilitrienone 2b, which was characterized by X-ray crystallography. In the absence of the para-nonyl groups bilitrienone 2a undergoes a rapid hydration reaction, giving biladienone 3a as the major isolated product. The molecular structures of 2b and 3a, and the photochemical isomerization of 3a are discussed.

Evaluation of the influence of proline, hydroxyproline or pyrrolidine in the presence of sodium nitrite on N-nitrosamine formation when heating cured meat

N-nitrosamines are meant to be probable or possible carcinogenic components, possibly formed out of a reaction between nitrite and N-containing substances such as amino acids and secondary amines. Nitrite is often used for processing meat products because of its colouring and antimicrobial properties. During this experimental setup, the influence of proline, hydroxyproline or pyrrolidine on N-nitrosamine formation in meat samples was evaluated. The N-nitrosamines concentrations were measured with gas chromatography-thermal energy analyzer. Only the concentrations of N-nitrosodimethylamine and N-nitrosopyrrolidine were found above the limit of detection in a number of tested experimental conditions. The concentration of these two N-nitrosamines was modelled as a function of temperature and nitrite concentration for different situations (presence or absence of added natural N-containing meat components). It could be concluded that proline and pyrrolidine promoted the formation of N-nitrosopyrrolidine. It could also be confirmed that the higher the temperature of the meat processing procedure and the higher the sodium nitrite amounts added, the higher were the yields of the respective N-nitrosamines.

ChemInform Abstract: Unexpected Result of the Reaction of Perimidines with 1,3,5‐Triazine in the Presence of Sodium Nitrite.

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Synthesis and application of a highly efficient tetraester calix[4]arene based resin for the removal of Pb 2+ from aqueous environment

The present study describes the Pb 2+ sorption potential of newly synthesized tetraester calix[4]arene (TC4) based resin from aqueous media. The TC4 resin was synthesized through diazotization reaction of TC4 with Amberlite XAD-4 in the presence of sodium nitrite in acidic medium. The TC4 resin was characterized by using different analytical techniques such as FT-IR, elemental analysis and scanning electron microscopy (SEM). The Pb 2+ removal ability of the resin from the aqueous environment has been evaluated by both batch adsorption as well as column studies. The experiments have been conducted involving the determination of effect of pH, adsorbate concentration, adsorbent dosage, contact time and temperature. Moreover, on the basis of kinetic studies, the pseudo-first-order and pseudo-second-order adsorption kinetics were calculated. The thermodynamic parameters of lead adsorption were also calculated. Equation isotherms such as Langmuir (L), Freundlich (F), and Dubinin–Radushkevich (D–R) were successfully used to model the experimental data. From the D–R isotherm parameters, it was considered that the uptake of Pb 2+ by TC4 resin is ion exchange mechanism. From the results it has been found that the TC4 resin is a versatile adsorbent for the removal of Pb 2+ from the aqueous environment. The study also confers its impact on human health, reinstate of polluted sites and other fields of material science.

Joint Theoretical Experimental Investigation of the Electron Spin Resonance Spectra of Nitroxyl Radicals: Application to Intermediates in in Situ Nitroxide Mediated Polymerization (in Situ NMP) of Vinyl Monomers

Density functional theory (DFT) calculations have been performed to address the structure of nitroxide intermediates in controlled radical polymerization. In a preliminary step, the reliability of different theoretical methods has been substantiated by comparing calculated hyperfine coupling constants (HFCCs) to experimental data for a set of linear and cyclic alkylnitroxyl radicals. Considering this tested approach, the nature of different nitroxides has been predicted or confirmed for (a) the reaction of C-phenyl- N- tert-butylnitrone and AIBN, (b) N- tert-butyl-alpha-isopropylnitrone and benzoyl peroxide, (c) tert-butyl methacrylate polymerization in the presence of sodium nitrite as mediator, and (d) for the reaction of a nitroso compound with AIBN. Values of HFCC experimentally determined have been confirmed by DFT calculations.

Unexpected result of the reaction of perimidines with 1,3,5-triazine in the presence of sodium nitrite

Unexpected result of the reaction of perimidines with 1,3,5-triazine in the presence of sodium nitrite

Nitrite-Derived Nitric Oxide Protects the Rat Kidney against Ischemia/Reperfusion Injury In Vivo

In normal conditions, nitric oxide (NO) is oxidized to the anion nitrite, but in hypoxia, this nitrite may be reduced back to NO by the nitrite reductase action of deoxygenated hemoglobin, acidic disproportionation, or xanthine oxidoreductase (XOR). Herein, is investigated the effects of topical sodium nitrite administration in a rat model of renal ischemia/reperfusion (I/R) injury. Rats were subjected to 60 min of bilateral renal ischemia and 6 h of reperfusion in the absence or presence of sodium nitrite (30 nmol) administered topically 1 min before reperfusion. Serum creatinine, serum aspartate aminotransferase, creatinine clearance, fractional excretion of Na(+), and plasma nitrite/nitrate concentrations were measured. The nitrite-derived NO-generating capacity of renal tissue was determined under acidic and hypoxic conditions by ozone chemiluminescence in homogenates of kidneys that were subjected to sham, ischemia-only, and I/R conditions. Nitrite significantly attenuated renal dysfunction and injury, an effect that was abolished by previous treatment of rats with the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazole-1-oxyl-3-oxide (2.5 mumol intravenously 5 min before ischemia and 50 nmol topically 6 min before reperfusion). Renal tissue homogenates produced significant amounts of NO from nitrite, an effect that was attenuated significantly by the xanthine oxidoreductase inhibitor allopurinol. Taken together, these findings demonstrate that topically administered sodium nitrite protects the rat kidney against I/R injury and dysfunction in vivo via the generation, in part, of xanthine oxidoreductase-catalyzed NO production. These observations suggest that nitrite therapy might prove beneficial in protecting kidney function and integrity during periods of I/R such as those encountered in renal transplantation.

Sodium Nitrite‐Catalyzed Oxybromination of Aromatic Compounds and Aryl Ketones with a Combination of Hydrobromic Acid and Molecular Oxygen under Mild Conditions

AbstractA novel and efficient catalytic system for the oxybromination of aromatic compounds and aryl ketones utilizing a combination of aqueous hydrobromic acid and molecular oxygen in the presence of sodium nitrite under mild conditions has been developed. The newly developed catalytic system utilizes cheap and readily available reactants, exhibits high bromine atom economy and releases only innocuous water as the by‐product.

Cyclic trimeric perfluoro- o-phenylenemercury: a highly efficient phase transfer catalyst for nitration of aromatic substrates with dilute nitric acid

Cyclic trimeric perfluoro- o-phenylenemercury ( o-C 6F 4Hg) 3 ( 1) exhibits a high catalytic activity in the phase transfer nitration of various aromatic substrates (2-methylnaphthalene, 1,3- and 2,6-dimethylnaphthalenes, acenaphthene, anthracene, pyrene) with dilute nitric acid in the presence of sodium nitrite as an initiator and sodium chloride as a promoter. The reactions proceed at room temperature in good or close to quantitative yields. In the absence of the catalyst, the rate of the process is sharply diminished. The best results in the nitration were obtained on using benzene–nitrobenzene mixtures as the organic phase. The replacement of the PhH/PhNO 2 mixtures by benzene decreases the reaction rate. An important role in these reactions is played by sodium chloride in the absence of which the catalyst completely loses its activity. Mercury dichloride and bis(perfluorophenyl)mercury do not catalyse the phase transfer nitration with dilute nitric acid even in the presence of sodium chloride. The mechanism of the promoting influence of NaCl on the process of the nitration is discussed. The ability of macrocycle 1 to catalyse the proton transfer from an aqueous phase to an organic phase is also reported.

Catalytic adsorptive stripping voltammetry versus electrothermal atomic absorption spectrometry in the determination of trace cobalt and chromium in human urine

Two methods of the determination of cobalt and chromium in human urine of non-occupationally exposed populations—highly sensitive catalytic adsorptive stripping voltammetry (CAdSV) and electrothermal atomic absorption spectrometry (ET-AAS)—are evaluated and compared. The CAdSV methods are based on adsorptive accumulation of a cobalt–nioxime (1,2-cyclohexanedione dioxime) or a chromium–DTPA (diethylenetriammine- N, N, N′, N″, N″-pentaacetic acid) complexes on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of the catalytic reduction current of the adsorbed complex in the presence of sodium nitrite in case of cobalt or in the presence of sodium nitrate in case of chromium determination. In the CAdSV procedure UV-photolysis was used for the sample pre-treatment; the ET-AAS determination did not require any separate preliminary decomposition of the analyte urine samples. The accuracy of the procedures was checked by the analysis of commercially available quality control urine samples. The detection limits (3 σ) were 0.13 μg l −1 for Co and 0.18 μg l −1 for Cr in ET-AAS determination and 0.007 μg l −1 for Co and 0.002 μg l −1 for Cr in CAdSV measurements. Precision (R.S.D.) was less than 5% for both methods. The study has shown that the CAdSV is a more reliable and sensitive technique for the determination of very low cobalt and chromium contents in urine, the detection of which is not possible when using the AAS technique.