Nitrodiphenyl Ether Research Articles

Hybrid chitosan-coated manganese ferrite nanoparticles for electrochemical sensing of bifenox herbicide

A novel glassy carbon electrode (GCE) modified with hybrid chitosan-coated manganese ferrite nanoparticles (MnFe2O4@CTS) was applied for the electrochemical determination of bifenox, which is a nitrodiphenyl ether herbicide. The core-shell MnFe2O4@CTS nanoparticles were synthesized via ionic gelation and characterized by different techniques including transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, and thermogravimetric analysis. The modification of the GCE was performed by drop-casting method using MnFe2O4@CTS, previously dispersed by ultrasound. For the first time, the synthesized material was tested in the electroanalysis of environmental pollutants. The innovative modified MnFe2O4@CTS/GCE provided a significant increase of peak currents in the presence of bifenox. Electrochemical and interfacial characteristics of the electrodes were assessed by cyclic voltammetry and electrochemical impedance spectroscopy. Under optimized conditions of square wave voltammetry and supporting electrolyte, it was possible to observe a linear dependence between the anodic peak current and the concentration of bifenox in the range from 0.3 to 4.4 μmol L−1. The limit of detection was estimated as 0.09 µmol L−1. The selectivity of the sensor was verified in the presence of other pesticides and the river water matrix; the interference response was found to be lower than 5%. The sensor showed excellent intra-day and inter-day repeatability presenting a relative standard deviation of 3.99% and 5.79%, respectively. Electrochemical determination of bifenox was performed in river and tap water samples. The recovery values were in the range of 82–97%. The novel analytical platform MnFe2O4@CTS/GCE presented promising features for application in environmental analysis of bifenox.

Гербіциди з групи нітродифенілових етерів: застосування в Україні, методи контролю, методика визначення залишків оксифлуорфену в зерні та олії сої

A review of analytical methods for the determination of herbicide residues from the group of nitrodiphenyl ethers in the environment and agricultural products, developed and validated a method for oxyfluorfen determination in soybean grain and oil method GC/ECD, which meets regulatory requirements and solves the problem of toxicant control in the above matrices. The developed method uses modern methods of sample preparation, identification and quantification of oxyfluorfen (selective extraction, capillary gas-liquid chromatography (GC/ECD GC/MS). The method is validated according to EU requirements) (SANTE/12682/2019 quality control and analytical validation procedures for pesticide residues analysis in food and feed). Key words: gas-liquid chromatography, mass spectrometry, herbicides, nitrodiphenyl ethers, control, residual amounts.

Photolysis of oxyfluorfen in aqueous methanol

Photolysis of oxyfluorfen, an herbicide of the nitrodiphenyl ether class, was studied in aqueous methanol under UV and sunlight. UV irradiation was carried out in a borosilicate glass photoreactor (containing 250 ppm oxyfluorfen in 50% aqueous methanol) equipped with a quartz filter and 125 watt mercury lamp (maximum output 254 nm) at 25 ± 1°C. Sunlight irradiation was conducted at 28 ± 1°C in borosilicate Erlenmeyer flasks containing 250 ppm oxyfluorfen in 50% aqueous methanol. The samples from both the irradiated conditions were withdrawn at a definite time interval and extracted to measure oxyfluorfen content by gas chromatography-flame ionization detector for rate study. The half-life values were 20 hours and 2.7 days under UV and sunlight exposure, respectively. Photolysis of oxyfluorfen yielded 13 photoproducts of which three were characterized by infrared spectrophotometer and 1H NMR and 13C NMR spectroscopy. The rest of the photoproducts were identified by gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC). An ionization potential 70 eV was used for electron impact-mass spectrometry (EI-MS) and methane was used as reagent gas for chemical ionization-mass spectrometry (CI-MS). Two of the photoproducts were also synthesized for comparison. The main phototransformation pathways of oxyfluorfen involved nitro reduction, dechlorination, and hydrolysis as well as nucleophiles displacement reaction.

Effect of nitrofen in the final stages of development of the diaphragm muscle in rats

To evaluate the expression of myosin in muscle fibers of the diaphragm in experimental congenital diaphragmatic hernia (CDH). Fetuses of pregnant rats were divided into four groups: External Control (EC), composed of non-manipulated rats; Nitrofen, composed of pregnant rats that received 100 mg of nitrofen (2,4-dichloro-4'nitrodiphenyl ether) diluted in olive oil on gestational day (GD) 9.5, whose fetuses developed CDH (N+) or not (N-), and Olive Oil Placebo (OO), composed of pregnant rats that received the oil on the same GD. The fetuses were collected on GD 18.5, 19.5, 20.5 and 21.5 (term = 22 days). We obtained body weight (BW) and photographed the diaphragm area (DA), hernia area (HA) and subsequent calculated the HA/DA ratio in N+ group. Samples of Diaphragm muscle were processed for histological staining with H/E and immunohistochemistry (IHQ) for myosin. The fetuses of N- and N+ groups had decreased BW and DA compared to EC and OO groups (p < 0.001). HA was decreased on GD 18.5 compared to 21.5 (p < 0.001) and the HA/DA ratio showed no difference. IHQ showed decreased expression of myosin in nitrofen groups. CDH induced by nitrofen model contributes to the understanding of muscularization in the formation of the diaphragm where the myosin expression is decreased.

Electrochemical Study of Diphenyl Ether Derivatives Used as Herbicides

The electrochemical behaviour of five nitro diphenyl ethers used as herbicides is investigated in acetonitrile. A detailed study by cyclic voltammetry and exhaustive electrolysis is carried out for the anodic oxidation of 2-Chloro-6-nitro-3-phenoxyaniline (aclonifen) and shows that the major oxidation product is a dimeric compound. A mechanistic scheme involving a coupling process is postulated for the electrochemical oxidation of this compound. Furthermore, the use of differential pulse voltammetry on a glassy carbon electrode permits the selective determination ofaclonifen. The limit of detection is 0.6 μg/mL.

ChemInform Abstract: 4‐Hydroxy‐2′‐nitrodiphenyl Ether Analogues as Novel Tyrosinase Inhibitors.

AbstractA series of hydroxy‐ and nitro‐substituted diphenyl ethers are prepared as novel tyrosinase inhibitors.

4-Hydroxy-2'-Nitrodiphenyl Ether Analogues as Novel Tyrosinase Inhibitors

Tyrosinase ubiquitously existing from microorganisms to animals and plants is known to be the most critical and rate limiting enzyme during melanin biosynthesis. In order to develop new tyrosinase inhibitor we have synthesized 14 diphenyl ether compounds possessing hydroxyl, bromo, and nitro groups in the structure. Among the compounds prepared, 18 and 19 have shown much stronger inhibition of tyrosinase monophenolase function than arbutin used as a positive control. Both compounds 18 and 19 possess para-hydroxyphenyl moiety in their structure, which might reinforce the importance of p-hydroxyphenyl group in the tyrosinase inhibitory process. In the DPPH radical scavenging activity test, none of the compounds even 18 and 19 showed significant antioxidant activity. The results suggest that elaborate adjustment of diphenyl ether analogues with proper substituents have potential to be developed as new skin whitening agents working on the tyrosinase function.

Nitrophenoxy groups containing polybenzimidazoles as polymer electrolytes for fuel cells: Synthesis and characterization

AbstractPolybenzimidazoles containing different contents of pendant nitrophenoxy groups were prepared by condensation of 3,3′‐diamino‐benzidine with a mixture of 3,5‐dicarboxyl‐4′‐nitro diphenyl ether and isophthalic acid (IPA) in different ratios in polyphosphoric acid. The polymers are soluble in polar aprotic solvents, they have inherent viscosities in the range of 0.75–1.10 dL g−1 and they form tough and transparent films on solution casting. They have good thermal stability with initial decomposition temperature ranging from 380 to 416°C in nitrogen, good tensile strength ranging from 56 to 65 MPa and reasonably good oxidative stability. Phosphoric acid uptake of these polymers is low compared with PBI and membranes doped with phosphoric acid exhibit good proton conductivity in the range of 6.6× 10−3 to 1.9× 10−2 S/cm at 25°C and 1.2× 10−2 to 4.9× 10−2 S/cm at 175°C, compared with 3.9× 10−3 S/cm at 25°C and 3.2× 10−2 S/cm at 175°C for PBI. These membranes are suitable for applications as polymer electrolyte for fuel cell and presumably for gas separation at high temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

ChemInform Abstract: Novel Synthesis of Anthelmintic Drug 4‐Isothiocyanato‐4′‐nitrodiphenyl Ether and Its Analogues.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Novel Synthesis of Anthelmintic Drug 4-Isothiocyanato-4′-nitrodiphenyl Ether and Its Analogs

An efficient, mild, chemoselective, and convenient protocol for synthesis of isothiocyanate derivatives. This protocol was applied successfully in the novel synthesis of anthelmintic drug 4-isothiocyanato-4′-nitrodiphenyl ether and its analogs.

Ionic Liquid as Catalyst for Solid−Liquid Phase Transfer Catalyzed Synthesis of p-Nitrodiphenyl Ether

The novelties of solid−liquid phase transfer catalyzed synthesis of p-nitrodiphenyl ether from p-nitrochlorobenzene and potassium phenoxide were studied in detail with ionic liquids as phase transfer catalysts among others. Tetradecyl(trihexyl)phosphonium bromide was found to be the best catalyst leading to 100% selectivity toward the desired product p-nitrodiphenyl ether. Ionic liquids offer excellent conversions and selectivity, stability at high temperatures, and reusability in this reaction. A mathematical model was developed to study the kinetics of the reaction and used to extract both the rate constant and ion-exchange equilibrium constant. The contribution of the uncatalyzed reaction was also considered in this model. The activation energy and Gibb’s free energy for a combined ion exchange were also calculated. Microwave irradiation was also employed as an effective alternative to conventional heating.

Metabolism of Nitrodiphenyl Ether Herbicides by Dioxin-Degrading Bacterium Sphingomonas wittichii RW1

Nitrodiphenyl ether herbicides, including chlomethoxyfen, nitrofen, and oxyfluorfen are potent herbicides. Some metabolites and parent compounds are considered as possible mutagens and endocrine disruptors. Both properties pose serious hygienic and environmental risks. Sphingomonas wittichii RW1 is a well-known degrader of polychlorinated dibenzo- p-dioxins, dibenzofurans, and diphenyl ethers. However, no detailed research of its metabolic activity has been performed against pesticides with a diphenyl ether scaffold. In this study, we report S. wittichii RW1 as a very potent diphenyl ether herbicide-metabolizing bacterium with broad substrate specificity. The structures of metabolites were determined by instrumental analysis and synthetic standards. Most pesticides were rapidly removed from the culture medium in the order of nitrofen > oxyfluorfen > chlomethoxyfen. In general, herbicides were degraded through the initial reduction and N-acetylation of nitro groups, followed by ether bond cleavage. Relatively low concentrations of phenolic and catecholic metabolites throughout the study suggested that these metabolites were rapidly metabolized and incorporated into primary metabolism. These results indicate that strain RW1 has very versatile metabolic activities over a wide range of environmental contaminants.

A caffeine-sensitive membrane electrode: Previous misleading report and present approach

Although a previous study [S.S.M. Hassan, M.A. Ahmed, M.M. Saoudi, Anal. Chem. 57 (1985) 1126] had shown that a caffeine-sensitive electrode made with picrylsulfonate and 1-octanol as a cation-exchanger and a solvent mediator, respectively, had a wide working pH range (5.5–9.5) and exhibited a Nernstian response, we could not find such response in this electrode. The present result was reasonable, because the p K a value of caffeinium ion was reported to be around 0.7 and the neutral form of caffeine was predominant in the pH range examined. Thus, we reinvestigated the response characteristics of a caffeine electrode, taking into consideration the p K a value, and constructed a new electrode with a combination of the lipophilic cation-exchanger, tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate (HFPB), and the solvent mediator with high degree of dielectric constant, 2-fluoro-2′-nitrodiphenyl ether (FNDPE). This electrode showed a pH-dependent response to caffeinium ion and gave a detection limit of 50 μM with a slope of 55 mV per concentration decade at pH 2. The use of other solvent mediators was less effective than that of FNDPE. The electrode was applied for the determination of caffeine in some central stimulants.

Effects of antioxidant vitamins on molecular regulators involved in lung hypoplasia induced by nitrofen

Introduction Oxidant herbicide nitrofen (2,4-dichloro-4′-nitrodiphenyl ether) induces in rat embryos congenital diaphragmatic hernia (CDH) with lung hypoplasia. The present study aims at examining whether antioxidant vitamins A, E, and C reverse the effects of the teratogen in the lungs of exposed rats and how they modify the expression of molecular regulators known to be involved in their pathogenesis. Materials and Methods Wet lung weight–body weight ratio, total DNA, and total protein were determined. Thyroid transcription factor 1 (TTF-1), hepatocyte nuclear factor 3 β (HNF-3 β), and surfactant protein B (SP-B) proteins were measured by immunoblot assay in lung homogenates from rat fetuses exposed in utero to either nitrofen 100 mg intragastrically or vehicle. The coexpression of these factors in the alveolar epithelium was demonstrated by immunohistochemistry. The effects of the addition of vitamins A, C, and E were assessed by comparison with analysis of variance. Results Nitrofen decreased lung weight, total DNA, and total protein. The addition of antioxidant vitamins had no effect on lung weight, but increased DNA and protein contents. TTF-1, HNF-3 β, and SP-B proteins were decreased in lung homogenates of exposed rats with CDH. The addition of antioxidant vitamins nearly normalized these values. Conclusions The effects of nitrofen in fetal rat lungs are reversed in part by antioxidant vitamins by upregulating the expression of TTF-1, HNF-3 β, and SP-B. This approach could help to develop transplacental prenatal interventions for CDH.

Effects of Nitrofen and Vitamins A, C and E on Maturation of Cultured Human H441 Pneumocytes

Background/Aim: Nitrofen (2,4-dichloro-4´-nitrodiphenyl ether), a teratogen with oxidant properties, induces congenital diaphragmatic hernia (CDH) with lung hypoplasia and delayed lung development and maturation in rat embryos. Several phenotypic features of the alveolar epithelium including surfactant proteins A and B synthesis and its regulation by transcription factors are reproduced in cultured human H441 pneumocytes. The aim of the present study was to test whether vitamins A, E and C with anti-oxidant properties were able to recover the expression of such regulators in an in vitro setting. Materials and Methods: Cultured human H441 pneumocytes were treated with nitrofen with or without additional exposure to vitamins A, E and C. Thyroid transcription factor 1 (TTF-1), hepatocyte nuclear factor 3-β (HNF-3β) and hepatocyte nuclear factor 3-β surfactant protein B (SP-B) mRNAs were measured by real-time polymerase chain reaction (RT-PCR). The cells were also immunohistochemically stained for assessment of proliferation (PCNA) and apoptosis (bis-benzimide) status and SP-B and TTF-1 protein expressions. Results were compared by ANOVA with a significant threshold of 5%. Results: Nitrofen severely decreased TTF-1, HNF-3β and SP-B mRNA expression by H441 pneumocytes in culture. Addition of vitamin E normalized the levels of the three transcripts, while vitamin A normalized only those of TTF-1 and SP-B mRNA. Vitamin C was significantly beneficial only for SP-B transcript. Nitrofen decreased proliferation and TTF-1 and SP-B protein expressions with no apparent effect on apoptosis. Additional exposure to vitamins A, C or E rescued near normal values. Conclusions: The changes induced by nitrofen in cultured H441 human pneumocytes are reverted in part by anti-oxidant vitamins by upregulating TTF-1, HNF-3β and SP-B and stimulating proliferation and maturity in nitrofen-treated cells. These effects of anti-oxidant vitamins could be of some interest for developing new transplacental therapeutic strategies aimed at improving lung development and maturation in fetuses with CDH.

Novelties of selective synthesis of 3-methyl-4′-nitro-diphenyl ether under solid–liquid phase transfer catalysis

3-Methyl-4′-nitro-diphenyl ether, an important agrochemical, is normally synthesized by employing aprotic polar solvents, or Ullmann reaction at elevated temperatures leading to a number of by-products and the process is costly. The current paper presents a cost effective and simpler process of synthesis of 3-methyl-4′-nitro-diphenyl ether from sodium salt of m-cresol and p-chloronitrobenzene (PCNB) by using o-xylene as a solvent under solid–liquid phase transfer catalysis (S–L PTC), at 120 °C, which is 100% selective. The liquid–liquid (L–L) PTC process does not work at the same conditions due to poor reactivity of the ion-pair. A novel mathematical model is developed to determine simultaneously the rate constant and anion exchange equilibrium constant from the same set of data. This will be helpful in reactor design and scale up. The activation energy and Gibb's free energy for a combined ion exchange and partitioning of ion pairs is are also calculated. The reactivity of sodium salts of o- and p-cresol with PCNB is also tested.

Synthesis of 3,4,4'- and 2',3,4-Triaminodiphenyl Ethers

Procedures were developed for preparing 3,4,4'- and 2',3,4-triaminodiphenyl ethers by the reaction of 4-acetylaminophenol with, respectively, 4-nitro- or 2-nitrochlorobenzene, followed by nitration of the resulting 4-acetylamino-4'- or -2'-nitrodiphenyl ether, hydrolysis of the product, 4-acetylamino-3,4'- or -2',3-dinitrodiphenyl ether, and reduction of 4-amino-3,4'- or -2'-3-dinitrodiphenyl ether.

Ultrastructural Changes in Placenta of Rats Treated with Nitrofen During Pregnancy

ABSTRACTNitrofen (2,4-dichloro-4′-nitrodiphenyl ether), a diapheny ether herbicide, is known to induce a variety of congenital cardiovascular anomalies together with diaphragmatic hernia and hydronephrosis in rat fetuses. After confirming pregnancy with the vaginal smear method, the primira rats were separated into two groups (n=30), a control group and an experimental group. On the first day of birth, the placenta regions were dissected under ketamine HCL anesthesia. The placental tissues of the nitrofen group and controls were compared microscopically. The results showed vascularisations in the gigant cells, edema in the placental stroma and trophoblastic cells in the basal zone that were significantly larger in the nitrofen group than in the control group except in the neonatal period.

Mutagenicity of sulfoscanate: a comparative study

The mutagenic activity of sulfoscanate (SSC) (4-isothiocyanate-4′-nitrodiphenyl sulphide) has been compared with that of the following reported drugs: (a) nitroscanate (NSC) (4-isothiocyanate-4′-nitrodiphenyl ether) which is a veterinary anthelmintic drug and (b) amoscanate (ASC) (4-isothiocyanate-4′-nitrodiphenyl amine) which is effective against schistosomes. SSC has been found to be a very potent mutagen towards TA98 and TA100 inducing 26.0 and 475.5 revertants/nmole, respectively. NSC was found to induce mutations at a rate of 11.1 and 21.5 revertants/nmole in TA98 and TA100, respectively. ASC was found to be non-mutagenic as such, but the urine of animals given the drug displayed mutagenicity. When SSC was tested in TA98/1,8-DNP 6, deficient in O-acetyltransferase, the activity decreased to 10.0 revertants/nmole. However, in case of NSC the mutagenic activity was reduced to 0.24 revertants/nmole, indicating the importance of O-acetyltransferase in generating N-acetoxyarylamine. In TA98NR, deficient in nitroreductase, the mutagenicity of SSC and NSC was totally absent. The positional isomers of SSC, 4-isothiocyanate-3′-nitro- and 4-isothiocyanate-2′-nitrodiphenyl sulphide, were found to be non-mutagenic in both TA98 and TA100. Our comparison of the mutagenic activity of SSC, NSC and ASC indicates that the pattern of activity is SSC>NSC>ASC.

Synthesis of haptens and protein conjugates for the development of immunoassays for the insect growth regulator fenoxycarb.

Sensitive and selective enzyme-linked immunosorbent assays (ELISAs) in the immobilized antigen format were developed for fenoxycarb (1), an insect growth regulator (IGR). The parent molecule [ethyl 2-(4-phenoxyphenoxy)ethylcarbamate] was derivatized at several positions to obtain haptens (2-5) that were used to produce protein conjugates and rabbit polyclonal antisera. Amino derivatives of fenoxycarb at the terminal and internal rings (2 and 3, respectively) were linked to carrier proteins by azo coupling. Carboxyalkyl-spacer groups were attached to the ethyl group and the nitrogen atom of the target compound (1) to obtain haptens 4 and 5, respectively. Hapten-homologous ELISAs based on protein conjugates of compounds 2 and 4 determined fenoxycarb in the mid-ppb range (IC(50), 102 and 95 ppb, respectively). A more sensitive hapten-heterologous ELISA (IC(50), 17 ppb; detection limit 0.5 ppb) involved the antiserum raised against a conjugate of hapten 2 and the plate-coating antigen obtained from compound 3. These assays displayed no significant interferences with photodegradation products of fenoxycarb, the IGRs methoprene and pyriproxyfen, and a variety of pesticides including the pyrethroids fenvalerate and cypermethryn, the phenoxyacetic acid herbicide 2,4-D, DDT, and the nitrodiphenyl ether herbicides acifluorfen and fluorodifen.