Presence Of Sodium Nitrite Research Articles

A Review on N-nitrosamine Impurity

Abstract: Nitrosamines are a category of substances that have a nitroso group linked to an amino group in their molecular structure. They are a category of carcinogens developed as a by-product of drug synthesis and also constituted in the presence of sodium nitrite or nitric acid and secondary amines (like dimethyl amines and diethyl amine) that must be monitored in drug production. In mid-June 2018, the Food and Drug Administration and the European Medicines Agency became aware of the existence of an impurity called N-nitrosamine in some frequently used medications, such as those for blood pressure, antacids, and diabetes. N-nitrosamines are of major concern because the ICH M7 (R1)2 guideline categorizes them as Class 1 impurities or mutagenic carcinogens, and the International Agency for Cancer Research categorizes them as potential carcinogens. The existence of N-nitrosamines in pharmaceutical drugs must be minimized to the greatest extent possible and must be at or below the threshold based on ICH M7(R1)2 fundamentals for materials in the "cohort of concern" described in this guideline and measured based on lifetime constant exposure.

Synthesis of Pyrazole Dyes Derivatives

Eight azo dyes were prepared by diazotization of 5-amino-3 (cyanomethyl)-1H- pyrazole-4-carbonitrile in presence of sodium nitrite and hydrochloric acid at 0°C. We reported that the malononitrile molecule was a very active nucleophile, where can react with the diazonium salt of pyrazole in presence of sodium acetate and ethanol to yield corresponding azo dyes of pyrazole. The dyes were characterized by elemental analysis and spectral methods. In addition, the effect of the pH value on the products yield of the dyes was reported.

Исследование нитрования сульфатного лигнина ацетилнитратом в апротонных растворителях

A method for homogeneous nitration of kraft lignin (KL), which consists in its treatment with acetyl nitrate in 1,4-dioxane, tetrahydrofuran, or dimethyl sulfoxide, has been proposed. The effects of reaction time and consumption of acetyl nitrate on KL nitration were studied. A new absorption band with a maximum at 430 nm due to aromatic nitro groups appears in the ionization spectra upon KL nitration. The intensity of this absorption band rises with an increase in consumption of acetyl nitrate and reaction time. At the same time, the intensities of two absorption bands of phenolic hydroxyl groups in the range of 230–300 nm decrease. At the highest acetyl nitrate consumption of 71 mmol / g KL, phenolic absorption bands are practically absent in the ionization spectrum of the products, which, apparently, can be explained by KL acetylation. To analyze the ionization spectra, they were deconvolved. The spectra of reaction products can be described by 3–5 Gaussians with an error of no more than 5 %. The proposed method makes it possible to synthesize the KL nitrated with nitrogen content of up to 2.4 %. Depending on the aprotic solvent used, the kinetic curves of nitration are different. A specific feature of KL nitration in tetrahydrofuran is the presence of an induction period, the duration of which decreases with increasing temperature and which practically disappears at temperatures above 30 °C. The introduction of small additions of nitrites into the reaction mixture makes it possible to reduce the induction period. The KL nitration in dimethyl sulfoxide occurs at a low rate that also increases significantly in the presence of sodium nitrite.

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

Aqueous Polyethylene Glycols as Green Reaction Media for the Nitration of Aromatic and Heterocyclic Compounds in Presence of Sodium Nitrite Under Transition Metal-Free and Mineral Acid-Free Conditions- A Kinetic Study

Aqueous Polyethylene Glycols as Green Reaction Media for the Nitration of Aromatic and Heterocyclic Compounds in Presence of Sodium Nitrite Under Transition Metal-Free and Mineral Acid-Free Conditions- A Kinetic Study

DETERMINATION OF Bisphenol A RELEASED FROM POLYCARBONATE INFANT FEEDING BOTTLES BY UV-VIS SPECTROPHOTOMETRY

Bisphenol A (BPA) is a synthetic organic compound used as a raw material for the production of polycarbonate plastics, which are widely used in infant feeding bottles, kitchen utensils and other food packaging materials. The migration of bisphenol A from polycarbonate feeding bottles into water and milk samples was investigated using UV-Vis spectrophotometry based on diazotization-coupling reaction. The proposed method involves diazotization of 4-aminobenzenesulphonic acid under acidic condition in the presence of sodium nitrite at low temperature, followed by its coupling with Bisphenol A, in alkaline medium to produce yellow color azo-dye. The diazo–coupling reagents and time were optimized, the azo-dye formed has absorption maximum at 439nm. BPA was detected within the range of 0.37 – 5.93 µg/mL in the samples using standard addition method. The validation parameters were LOD: 0.48 µg/mL, LOQ: 1.62 µg/mL, while recovery for spiked samples were averagely 97.87 – 99.63 % and %RSD ranged between 0.12- 4.9%. Milk samples have exceeded the tolerable daily intake (TDI) for BPA of 50μg/kgbw/day recommended by EFSA.

Synthesis and Applications of Aurin Tricarboxylic Acid-Copper Metal Organic Framework for Rechargeable Lithium-Ion Batteries

Organic electrode materials for lithium-ion batteries are essential tools for energy storage systems starting from portable electronics to electric vehicles. Many attempts have been made to improve the electrochemical behavior of organic electrode materials for lithium-ion batteries. Herein we have proposed a new electrode material called Aurin tricarboxylic acid synthesized via the condensation of aldehyde and acid in the presence of sodium nitrite which is further converted into the metal-organic framework using copper salt to increase its conductivity and used as an anode material for both aqueous and non-aqueous rechargeable lithium-ion batteries. The electrochemical performance of modified Aurin Tricarboxylic acid copper metal-organic framework (ATC-MOF) was studied using cyclic voltammetry, galvanostatic cycling with potential limitation and Potentio electrochemical impedance spectroscopy techniques and the structures were confirmed using 1H-NMR, FT-IR spectroscopy, and Powder XRD techniques. It exhibits excellent cyclability and a good discharge capacity of about 438.09 mA h g−1 in a non-aqueous electrolyte and 169.69 mAh g−1 in an aqueous electrolytic system. The electrochemical activity of the ATC-MOF shows that it can be used as electrode material in aqueous and non-aqueous rechargeable lithium-ion battery systems.

Colour analysis of organic synthetic dye coating paint films consisting 4-hydroxycoumarin derivatives after exposed to UV-A

This work investigates the visible optical stability of coating paint film consisting organic synthetic dye, 4-hydroxycoumarin derivatives to the exposure to ultraviolet A (UV-A) light. An azo dye was synthesized by coupling diazonium salt of aniline derivative (obtained by diazonation of 4-chloroaniline in presence of sodium nitrite and hydrochloric acid) with 4-hydroxycoumarin in the presence of sodium hydroxide. The azo dye was mixed with xylene before using it as a pigment in the coating composition. The mixture of poly(methyl methacrylate) (PMMA) and acrylic polyol was used as the coating binder. The synthesized dye and binder were then mixed at specific ratio to form a complete coating solution. Two coating solutions with PMMA having different molecular weights (Mw: 350,000 gmol−1 and Mw: 996,000 gmol−1) were used in this study. Each of them was labelled as 350 K and 996 K indicating its molecular weight. Both mixtures were applied as coating paint films on glass substrates were exposed to UV-A for fast photo-degradation process. The visible optical stability of the coating paint films was measured and recorded at an interval of eight-hours exposure for 35 days using the Commission Internationale de l’Eclairage (CIE) L*a*b* colour coordinate system. The obtained datas were analysed using standard deviation (STD). In this study, both coating samples showed low standard deviation for hue angle, namely 0.206 for 996 K and 0.258 for 350 K which indicates a high colour stability. However, the 350 K possesses a smaller colour difference (ΔE) of 0.798 compared to 1.418 for 996 K.

NaNO2/I2 as an alternative reagent for the synthesis of 1,2,3-benzotriazin-4(3H)-ones from 2-aminobenzamides

An efficient transformation of 2-aminobenzamides to 1,2,3-benzotriazin-4(3H)-ones in the presence of sodium nitrite (NaNO2) and Iodine (I2) is described. The reaction is proposed to proceed via formation of nitrosyl halide that induces nitrosylation of the amino group of 2-aminobenzamide leading to diazotization followed by intramolecular cyclization.

Three-Component Synthesis and Optical Properties of Nicotinic Acid Esters Containing Buta-1,3-dien-1,1,3-tricarbonitrile Fragment

Three-component synthesis of ethyl 4-aryl-2-methyl-5-cyano-6-(dicyanomethylidene)-1,6-dihydropyridine-3-carboxylates was developed consisting in the reaction of acetoacetic ester, aromatic aldehydes, and malononitrile dimer in the presence of sodium nitrite. Optical properties of synthesized compounds were investigated and it was demonstrated that they possessed intensive fluorescence in solution and in solid state with emission maxima in the yellow and green region of the visible light.

Stabilization of 4-phenylurazole by electrografting on a nano-fibrillated mesoporous carbon modified electrode. Reactivity of anchored triazolinedione groups against Michael-type addition at electrode/electrolyte interface

Fabricartion of a redox-active electrode by modification of a glassy carbon electrode (GCE) with a unique ionic liquid derived fibrillated mesoporous carbon (IFMC) following the electrografting of 4-phenylurazole via electrochemical reduction of 4-(4-nitrophenyl)urazole in the presence of sodium nitrite has been described. The resulted electrode shows the prominent electrochemical performance. The efficiency of the electrode has been evaluated over the entire range of pHs. The oxidized form of ungrafted 4-phenyluazole, 4-phenyl-1,2,4-triazoline-3,5-dione, is highly unstable due to fast ring cleavage. In contrast to oxidation of the ungrafted 4-phenylurazole, the electrografted 4-phenyl-1,2,4-triazoline-3,5-dione exhibits a high stability in a wide range of pHs. The anchored 4-phenyl-1,2,4-triazoline-3,5-dione groups are reactive against Michael-type addition. Further modification of the electrode can be achieved by the Michael-type addition reaction of the triazolinedione groups with nucleophiles at the solid/liquid interface.

Nitrite-derived nitric oxide reduces hypoxia-inducible factor 1α-mediated extracellular vesicle production by endothelial cells

IntroductionExtracellular vesicles (EVs) are small, spherical particles enclosed by a phospholipid bilayer (∼30–1000 nm) released from multiple cell types, and have been shown to have pathophysiological roles in a plethora of disease states. The transcription factor hypoxia-inducible factor-1 (HIF-1) allows for adaptation of cellular physiology in hypoxia and may permit the enhanced release of EVs under such conditions. Nitric oxide (NO) plays a pivotal role in vascular homeostasis, and can modulate the cellular response to hypoxia by preventing HIF-1 accumulation. We aimed to selectively target HIF-1 via sodium nitrite (NaNO2) addition, and examine the effect on endothelial EV, size, concentration and function, and delineate the role of HIF-1 in EV biogenesis. MethodsEndothelial (HECV) cells were exposed to hypoxic conditions (1% O2, 24 h) and compared to endothelial cells exposed to normoxia (21% O2) with and without the presence of sodium nitrite (NaNO2) (30 μM). Allopurinol (100 μM), an inhibitor of xanthine oxidoreductase, was added both alone and in combination with NaNO2 to cells exposed to hypoxia. EV and cell preparations were quantified by nanoparticle tracking analysis and confirmed by electron microscopy. Western blotting and siRNA were used to confirm the role of HIF-1α and HIF-2α in EV biogenesis. Flow cytometry and time-resolved fluorescence were used to assess the surface and intravesicular protein content. ResultsEndothelial (HECV) cells exposed to hypoxia (1% O2) produced higher levels of EVs compared to cells exposed to normoxia. This increase was confirmed using the hypoxia-mimetic agent desferrioxamine. Treatment of cells with sodium nitrite (NaNO2) reduced the hypoxic enhancement of EV production. Treatment of cells with the xanthine oxidoreductase inhibitor allopurinol, in addition to NaNO2 attenuated the NaNO2-attributed suppression of hypoxia-mediated EV release. Transfection of cells with HIF-1α siRNA, but not HIF-2α siRNA, prior to hypoxic exposure prevented the enhancement of EV release. ConclusionThese data provide evidence that hypoxia enhances the release of EVs in endothelial cells, and that this is mediated by HIF-1α, but not HIF-2α. Furthermore, the reduction of NO2− to NO via xanthine oxidoreductase during hypoxia appears to inhibit HIF-1α-mediated EV production.

Palladium-Catalyzed C–H Monoalkoxylation of α,β-Unsaturated Carbonyl Compounds

An efficient method for the direct introduction of alkoxy groups into the β-position of alkene moieties of various α,β-unsaturated carbonyl compounds through the palladium-catalyzed C(sp2)–H monoalkoxylation using alcohols in the presence of sodium nitrite was developed; the corresponding enol ethers were selectively synthesized with minimal generation of acetals.

Synthesis and Characterization of Some New Azo Dyes Derivatives Via Chalcone and Study Some of Their Biological Activity

This work includes synthesis of new six membered heterocyclic rings with effective amino group using the reaction of benzylideneacetophenone (chalcone) (1) with thiourea or urea in alcoholic basic medium to form: 1,3-thiazen-2-amine (2), and 1,3-oxazin-2-amine (8) respectively. The diazotization reaction was carried out with sodium nitrite in presence of hydrochloric acid to form diazonium salts which suffered coupling reaction with naphthols and phenols in the presence of sodium hydroxide to form colored azo dyes (4-7, and 10-13). o-methylation reaction of compounds (7) and (10) yielded : 1,3-thiazin -2-yl-diazenyl (14), and 1,3-oxazin-2-yl-diazenyl (15) respectively.The new compounds were characterized using various physical techniques like: UV-Vis., FT-IR, and 1HNMR spectra. Some new compounds were tested against bacteria.

Green Synthesis of Tetrazines and their Role as Human Cytomegalovirus (HCMV) Protease Inhibitor

Herein, we report a one-pot, efficient, and environmentally benign synthesis of biological and pharmacological potent tetrazines and tetrazines were synthesized via reaction of benzyl cyanide and hydrazine in the presence of sodium nitrite and hydrochrloic acid at room temperature in bronsted acidic ionic liquid as a green solvent and efficient catalytic media. Further, computational studies of the synthesized tetrazines have been performed against Human cytomegalovirus (HCMV) protease and found to inhibitors for HCMV. Therefore, tetrazines have been proposed as potent antiviral agents.

Synthesis and Characterization of Some New Azo Dyes Derivatives Via Chalcone and Study Some of Their Biological Activity

This work includes synthesis of new six membered heterocyclic rings with effective amino group using the reaction of benzylideneacetophenone (chalcone) (1) with thiourea or urea in alcoholic basic medium to form: 1,3-thiazen-2-amine (2), and 1,3-oxazin-2-amine (8) respectively. The diazotization reaction was carried out with sodium nitrite in presence of hydrochloric acid to form diazonium salts which suffered coupling reaction with naphthols and phenols in the presence of sodium hydroxide to form colored azo dyes (4-7, and 10-13). o-methylation reaction of compounds (7) and (10) yielded : 1,3-thiazin -2-yl-diazenyl (14), and 1,3-oxazin-2-yl-diazenyl (15) respectively.The new compounds were characterized using various physical techniques like: UV-Vis., FT-IR, and 1HNMR spectra. Some new compounds were tested against bacteria.

English

Listeria monocytogenes is widely distributed in nature and has been isolated from numerous sources such as meat and fermented meat products. This pathogenic microorganism can resist conditions of low pH, low water activity (Aw), high salt (NaCl) concentrations and the presence of sodium nitrite, being able to survive the commercial sausage manufacturing process. The aim of this work was to evaluate the antilisterial activity of a lactic acid bacterium (Lactococcus lactis subsp. lactis PD 6.9) isolated from Italian-style salami in conditions that simulate salami fermentation. L. lactis PD 6.9 produces nisin Z and grows well in pork lean meat broth, a feature that would be useful to compete with food-borne pathogens. The peak of nisin Z production by L. lactis PD 6.9 in pork lean meat broth occurred after 14 h of fermentation, but the inhibitory activity decreased if the producer organism was maintained in stationary phase. When L. lactis PD 6.9 (107CFU ml-1) and Listeria monocytogenes LMA 20 (106CFU ml-1) were co-inoculated in pork lean meat broth, growth of L. lactis PD 6.9 was unaffected. The decrease in viable cell number of Listeria coincided with an increase in bacteriocin activity produced by L. lactis PD 6.9 in pork lean meat broth. Co-culture experiments indicated that L. lactis PD 6.9 was able to control the growth of L. monocytogenes even if the Listeria population was 1000-fold greater than the L. lactis population. These results demonstrate the potential application of L. lactis PD 6.9 in controlling the growth of L. monocytogenes during salami fermentation and its usefulness as a starter culture for fermented sausages. Key words: Listeria monocytogenes, bacteriocins, lactic acid bacteria, co-cultivation, salami.

Optimizing the usability of unwanted latex yield by in situ depolymerization and functionalization

Functionalized liquid natural rubber (FLNR) derived from unwanted latex yield was synthesized by redox method using hydrogen peroxide (H2O2) in the presence of sodium nitrite (NaNO2). Hydroxylation was confirmed by FTIR with a peak at 3424cm−1. Response surface methodology was used to investigate the effect of varying feed parameters towards response of molecular weights and OH values. Response surface contours were constructed for modeling the relationship between processing factors and response output. The developed models show NaNO2 as the main factor followed by H2O2 that influences the FLNR properties. Multi response optimization was done using Derringer’s desirability function. The optimum conditions for minimizing Mn and MWD while maximizing OH value was determined to be at low ratios of NaNO2/H2O2 and high ratios of H2O2/isoprene unit. The predicted optimum response for Mn was around 30,000g/mol, MWD between 1.48 and 1.61 and OH value between 194 and 229mg KOH/g.

Химическое окисление продуктов трансформации несимметричного диметилгидразина в воде

Oxidation of unsymmetrical dimethylhydrazine (UDMH) during a water treatment has several disadvantages including formation of stable toxic byproducts. Effectiveness of treatment methods in relation to UDMH transformation products is currently poorly studied. This work considers the effectiveness of chemical oxidants in respect to main metabolites of UDMH – 1-formyl-2,2-dimethylhydrazine, dimethylaminoacetontrile, N-nitrosodimethylamine and 1-methyl-1H-1,2,4-triazole. Experiments on chemical oxidation by Fenton's reagent, potassium permanganate and sodium nitrite were conducted. Quantitative determination was performed by HPLC. Oxidation products were identified by gas chromatography-mass spectrometry in combination with solid-phase microextraction. 1-Formyl-2,2-dimethylhydrazine was completely oxidized by Fenton's reagent with formation of formaldehyde N-formyl-N-methyl-hydrazone, 1,4-dihydro-1,4-dimethyl-5H-tetrazol-5-one by the action of potassium permanganate and N-methyl-N-nitro-methanamine in the presence of sodium nitrite. Oxidation of 1-formyl-2,2-dimethylhydrazine also resulted in formation of N-nitrosodimethylamine. Oxidation of dimethylaminoacetontrile proceeded with formation of hydroxyacetonitrile, dimethylformamide and 1,2,5-trimethylpyrrole. After 30 days, dimethylaminoacetontrile was not detected in the presence of Fenton’s reagent and potassium permanganate, but it’s concentration in samples with sodium nitrite was 77.3 mg/L. In the presence of Fenton’s reagent, potassium permanganate and sodium nitrite after 30 days, N-nitrosodimethylamine concentration decreased by 85, 80 and 50%, respectively. In control sample, N-nitrosodimethylamine concentration decreased by 50%, indicating that sodium nitrite has no effect of on N-nitrosodimethylamine concentration. Only Fenton's reagent allowed to reduce the concentration of 1-methyl-1H-1,2,4-triazole to 50% in 30 days. In the presence of other oxidants, 1-methyl-1H-1,2,4-triazole concentration decreased by 15-20%. As a result of the experiment, Fenton's reagent proved to be the most effective oxidant.

Mechanistic studies on formation of the dinitrosyl iron complex of the [2Fe-2S] cluster of SoxR protein.

The transcriptional activation of SoxR in Escherichia coli occurs through direct modification of the [2Fe-2S] by nitric oxide (NO) to form a dinitrosyl iron complex (DNIC). Here, we investigated the reactions of NO with [2Fe-2S] clusters of SoxR; the results were compared with those obtained for spinach ferredoxin (Fd). UV-visible absorption and ESR spectra of SoxR upon treatment with an NO donor showed the formation of DNIC of SoxR efficiently, whereas those of Fd exhibited small changes. Upon pulse radiolysis of a deaerated solution of SoxR in the presence of sodium nitrite, a biphasic change in absorption, consisting of a faster phase and a slower phase, was observed. The slower phase fraction was increased with increases in the [NO]/[SoxR] molar ratio, reaching a plateau at ∼2 equivalents of NO. On the basis of these results, we propose that the faster phase corresponds to the reaction of the first NO molecule with [2Fe-2S] of SoxR, followed by the reaction of the second NO molecule. In the reaction of NO with Fd, no slower phase was observed. These results suggest that the reaction of the second equivalent of NO is an important process for the formation of DNIC.