Phenoxyacetic Acids Research Articles

Sensitivity change of the modified carbon paste electrodes for detection of chlorinated phenoxyacetic acids

Sensitivity change of the modified carbon paste electrodes for detection of chlorinated phenoxyacetic acids

Combining crop-exposure matrices and land use data to estimate indices of environmental and occupational exposure to pesticides.

Exposure assessment represents a major challenge for studies on the relation between pesticides and health. We developed a method combining information from crop-exposure matrices (CEMs) and land use data, in order to compute indices of environmental and occupational pesticide exposure. We illustrate our approach using French data (1979-2010). We used CEMs for five crops (straw cereals, grain corn, corn fodder, potatoes, vineyards) that describe use (annual probability, frequency, intensity) of pesticide subgroups, chemical families, and active substances by region and time since 1960. We combined these data with land use data from agricultural censuses (1979, 1988, 2000, 2010) to compute indices of environmental and occupational pesticide exposure in cantons (small French administrative units). Indices of environmental exposure were calculated based on the area of each crop in the cantons, while indices of occupational exposure depended on combinations of crops in each farm from the cantons. To illustrate our approach, we selected a pesticide group (herbicides), chemical family of herbicides (phenoxyacetic acids), and active substance from the phenoxyacetic acids chemical family (2,4-D). The estimated proportion of the area of crops with CEMs and of farms sprayed with herbicides was close to 100% between 1979-2010, but the estimated average annual number of applications increased. There were decreasing time-trends for phenoxyacetic acids and 2,4-D over the same period for all indices of exposure. There was a high use of herbicides throughout France in 2010, except in the South coast. For phenoxyacetic acids and 2,4-D, the spatial distribution was heterogeneous for all indices of exposure, with the highest values in the Centre and North regions. Assessment of pesticide exposure is a key issue for epidemiological studies on their association with health outcomes. However, it presents some unique challenges, particularly for retrospective exposure and the investigation of chronic diseases. We present a method to compute indices of exposure by combining information from crop-exposure matrices for five crops and land use data. Specificities of environmental and occupational exposure are addressed using different methods. These methods are applied to pesticides used in agriculture in France for five crops (3 groups, 91 chemical families,197 activesubstances) to produce indices at a small geographic scale from 1979 to 2010 for the whole metropolitan France. Besides using these indices in French epidemiological studies, our approach could be relevant for other countries.

Exposure to phenoxyacetic acids and glyphosate as risk factors for non-Hodgkin lymphoma– pooled analysis of three Swedish case-control studies including the sub-type hairy cell leukemia

The association between pesticide exposure and non-Hodgkin lymphoma (NHL) including hairy cell leukemia (HCL) was analyzed in a pooled study of three case-control studies. Results on exposure to pesticides were based on 1,425 cases and 2,157 controls participating in the studies. Exposures were assessed by self-administered questionnaires completed as needed by phone. In the pooled univariate analyses adjusted by age, gender and year of diagnosis, exposure to herbicides of the phenoxyacetic acid type yielded statistically significant increased risk with odds ratio (OR) = 1.9, 95% confidence interval CI) = 1.4–2.5. The herbicide glyphosate gave OR = 2.2, 95% CI = 1.3–3.8. Impregnating agents increased the risk. No clear dose-response effect was seen. OR was highest in the >10–20 years latency group for herbicides and impregnating agents. In the multivariate analysis including main pesticide groups, statistically significant increased risk was found for herbicides, OR = 1.6, 95% CI = 1.2–2.1 and impregnating agents with OR = 1.4, 95% CI = 1.1–1.8. This analysis confirmed an association between NHL including HCL and exposure to certain herbicides.

Deashed Wheat-Straw Biochar as a Potential Superabsorbent for Pesticides.

Biochar activation methods have attracted extensive attention due to their great role in improving sorptive properties of carbon-based materials. As a result, chemically modified biochars gained application potential in the purification of soil and water from xenobiotics. This paper describes changes in selected physicochemical properties of high-temperature wheat-straw biochar (BC) upon its deashing. On the pristine and chemically activated biochar (BCd) retention of five pesticides of endocrine disrupting activity (carbaryl, carbofuran, 2,4-D, MCPA and metolachlor) was studied. Deashing resulted in increased sorbent aromaticity and abundance in surface hydroxyl groups. BCd exhibited more developed meso- and microporosity and nearly triple the surface area of BC. Hydrophobic pesticides (metolachlor and carbamates) displayed comparably high (88-98%) and irreversible adsorption on both BCs, due to the pore filling, whereas the hydrophilic and ionic phenoxyacetic acids were weakly and reversibly sorbed on BC (7.3 and 39% of 2,4-D and MCPA dose introduced). Their removal from solution and hence retention on the deashed biochar was nearly total, due to the increased sorbent surface area and interactions of the agrochemicals with unclogged OH groups. The modified biochar has the potential to serve as a superabsorbent, immobilizing organic pollutant of diverse hydrophobicity from water and soil solution.

Evaluation of herbicidal and fungicidal activities of six natural components and their phenoxyacetic acids derivatives and assessment of human health risk posed by oral exposure to them

ABSTRACT In the present study, we isolated linalool, geraniol, carvacrol, thymol, menthol and eugenol; synthesised their phenoxyacetic acid derivatives; and assessed their phytotoxic and genotoxic potentials against weeds and agricultural crops. Moreover, the fungicidal activity of both categories of compounds against 12 fungi was examined. Finally, using probabilistic assessment based on Risk Quotient (RQ) by the Monte Carlo simulation (MCS) method, we examined human health risks via oral exposure to these compounds. Toxic potencies to plants demonstrated that all parameters and related indices including germination percentage, mean germination time, germination rate, root length, shoot length, seedling length and vigour index dose-dependently decreased in both weeds and agricultural crops. Based on the comet assay, DNA damage was observed in the root meristems of the plants. Consequently, a significant decrease was observed in head DNA, whereas a significant increase in tail DNA was observed in response to treatments. Besides, the natural components and semisynthetic molecules showed a broad spectrum of fungicidal traits. However, eugenol and eugenoxyacetic acid inhibitory effects on the growth of the tested fungi were similar to that of benomyl. Our probabilistic health risk assessment indicated di minimis risk for natural components and their phenoxyacetic acid derivatives. Sensitivity analysis showed that concentrations of residues of the compounds had the most significant effect on risk. Current findings could offer a platform for developing sustainable approaches to reduce chemical residues and their consequent risks to the environment and human health.

Electrochemical Determination of 4-Bromophenoxyacetic Acid Based on CeO2/eGr Composite.

The determination of plant growth regulators is of great importance for the quality monitoring of crops. In this work, 4-bromophenoxyacetic acid (4-BPA), one of the phenoxyacetic acids, was detected via the electrochemical method for the first time. A CeO2-decorated electrochemical exfoliated graphene (eGr) composite (CeO2/eGr) was constructed as the sensor for sensitive detection of 4-BPA due to the synergistic effect of the excellent catalytic active sites of CeO2 and good electron transference of the eGr. The developed CeO2/eGr sensor displayed a good linearity in a wide range from 0.3 to 150 μmol/L and the lowest detection limit of 0.06 μmol/L for 4-BPA detection. Electrochemical oxidation of 4-BPA follows a mix-controlled process on the CeO2/eGr electrode, which involves 2e in the transference process. This developed CeO2/eGr sensor has excellent repeatability with a relative standard deviation (RSD) of 2.35% in 10 continuous measurements. Moreover, the practical application of the sensor for 4-BPA detection in apple juice has recoveries in the range of 90–108%. This proposed CeO2/eGr sensor has great potential for detecting plant growth regulators in the agricultural industry.

Quantitative Retention (Structure)-Activity Relationships in Predicting the Pharmaceutical and Toxic Properties of Potential Pesticides.

The micellar liquid chromatography technique and quantitative retention (structure)–activity relationships method were used to predict properties of carbamic and phenoxyacetic acids derivatives, newly synthesized in our laboratory and considered as potential pesticides. Important properties of the test substances characterizing their potential significance as pesticides as well as threats to humans were considered: the volume of distribution, the unbonded fractions, the blood–brain distribution, the rate of skin and cell permeation, the dermal absorption, the binding to human serum albumin, partitioning between water and plants’ cuticles, and the lethal dose. Pharmacokinetic and toxicity parameters were predicted as functions of the solutes’ lipophilicities and the number of hydrogen bond donors, the number of hydrogen bond acceptors, and the number of rotatable bonds. The equations that were derived were evaluated statistically and cross-validated. Important features of the molecular structure influencing the properties of the tested substances were indicated. The QSAR models that were developed had high predictive ability and high reliability in modeling the properties of the molecules that were tested. The investigations highlighted the applicability of combined chromatographic technique and QS(R)ARs in modeling the important properties of potential pesticides and reducing unethical animal testing.

Unusual Catalytic Effect of Fe3+ on 2,4-dichlorophenoxyacetic Acid Degradation by Radio Frequency Discharge in Aqueous Solution

2,4-dichlorophenoxyacetic acid (2,4-D) is a widely used herbicide for controlling broad-leaved weeds. The development of an efficient process for treating the refractory 2,4-D wastewater is necessary. In this study, liquid-phase degradation of 2,4-D induced by radio frequency discharge (RFD) was studied. Experimental results showed that the degradation was more effective in acidic than in neutral or alkaline solutions. During the degradation, a large amount of hydrogen peroxide (H2O2, 1.2 mM/min, almost equal to that without 2,4-D) was simultaneously produced, and catalytic effects of both ferric (Fe3+) and ferrous (Fe2+) ions on the degradation were examined and compared. It was found that 2,4-D degraded more rapidly in the case of Fe3+ than the that of Fe2+. Such a scenario is explained that Fe3+ was successively reduced to Fe2+ by the atomic hydrogen (•H) and •OH-adducts of 2,4-D resulting from RFD, which in turn catalyzed the H2O2 to form more •OH radicals through Fenton’s reaction, indicating that Fe3+ not only accelerates the degradation rate but also increases the amount of •OH available for 2,4-D degradation by suppressing the back reaction between the •H and •OH. 2,4-dichlorophenol, 4,6-dichlororesorcinol, 2-hydroxy-4-chloro- and 2-chloro-4-hydroxy- phenoxyacetic acids, hydroxylated 2,4-Ds, and carboxylic acids (glycolic, formic and oxalic) were identified as the byproducts. Energy yields of RFD have been compared with those of other nonthermal plasma processes.

Novel Imidazole Phenoxyacetic Acids as Inhibitors of USP30 for Neuroprotection Implication via the Ubiquitin-Rho-110 Fluorometric Assay: Design, Synthesis, and In Silico and Biochemical Assays.

USP30, a deubiquitinating enzyme family, forfeits the ubiquitination of E3 ligase and Parkin on the surface of mitochondria. Inhibition of USP30 results in mitophagy and cellular clearance. Herein, by understanding structural requirements, we discovered potential USP30 inhibitors from an imidazole series of ligands via a validated ubiquitin-rhodamine-110 fluorometric assay. A novel catalytic use of the Zn(l-proline)2 complex for the synthesis of tetrasubstituted imidazoles was identified. Among all compounds investigated, 3g and 3f inhibited USP30 at IC50 of 5.12 and 8.43 μM, respectively. The binding mode of compounds at the USP30 binding site was understood by a docking study and interactions with the key amino acids were identified. Compound 3g proved its neuroprotective efficacy by inhibiting apoptosis on SH-SY5Y neuroblastoma cells against dynorphin A (10 μM) treatment. Hence, the present study provides a new protocol to design and develop ligands against USP30, thereby offering a therapeutic strategy under conditions like kidney damage and neurodegenerative disorders including Parkinson's disease.

OXIDATION KINETICS OF PHENOL, ITS DERIVATIVES AND SOME PARA-SUBSTITUTED PHENOL BY PYRAZINIUM CHLOROCHROMATE IN ACIDIC MEDIUM: A NON-LINEAR HAMMETT PLOTS

In the presence of perchloric acid, the kinetics and oxidation of phenol, phenoxy acetic acid, and a few para-substituted phenols and phenoxyacetic acids by pyrazinium chlorochromate (PzCC) were investigated in acetic acid and water medium. The reaction was fractional-order for both the substrates and unit order for oxidant and acid. The products of oxidation are quinone. Comparing the reaction rate for phenols and their derivatives revealed a similar behavior. The oxidation and kinetics of phenol and its derivatives are established using the non-linear Hammett plots plot which reveal that para-methyl groups slow down the reaction rate and para-nitro and para-chloro groups speed up the reaction rate. Based on the kinetic data and product analyses, an appropriate mechanism has been provided

ХАРАКТЕРИСТИКА ПРЕДСТАВИТЕЛЯ РОДА CELLULOSIMICROBIUM КАК ДЕСТРУКТОРА 2,4-ДИХЛОРФЕНОКСИУКСУСНОЙ КИСЛОТЫ

On the basis of the cultural, morphological, physiological and biochemical features, the taxonomic position of the NPZ-121 strain (isolated from the soil contaminated with chemical waste in Ufa (Russia)) as belonging to the species Cellulosimicrobium funkei was specified. In a batch culture the dynamics of growth of the strain C. funkei NPZ-121 and utilization of 2,4-dichlorophenoxyacetic acid at a concentration of 100 mg/l were described. For 11 days the culture used up to 69% of the substrate from the initial value. The ability of the strain to metabolize 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was revealed previously. Thus, the polysubstrate activity to chlorinated phenoxyacetic acids of the NPZ-121 strain was established.

Bioactivity and molecular properties of Phenoxyacetic Acids Derived from Eugenol and Guaiacol compared to the herbicide 2,4-D.

Herbicides are agrochemicals applied in the control of weeds. With the frequent and repetitive use of these substances, serious problems have been reported. Compounds of natural origin and their derivatives are attractive options to obtain new compounds with herbicidal properties. By aiming to develop compounds with potentiated herbicidal activity, phenoxyacetic acids were synthesized from eugenol and guaiacol. The synthesized compounds were characterized and the herbicidal potential of phenoxyacetic acids and precursors was evaluated through bioassays regarding the germination and initial development of Lactuca sativa and Sorghum bicolor seedlings, with the induction of DNA damage. The induction of changes in the mitotic cycle of meristematic cells of roots of L. sativa was also analyzed. At the concentration of 3 mmol L-1, phenols and their respective phenoxyacetic acids presented phytotoxic and cytotoxic activities in L. sativa and S. bicolor. Eugenol and guaiacol also presented genotoxic action in L. sativa. The toxic effect of eugenoxyacetic acid was more pronounced in L. sativa than in S. bicolor, similar to the commercial 2,4-D herbicide. Molecular properties of the phenols and their derivatives phenoxyacetic acids were compared with the ones obtained for the herbicide 2,4-D, where it was found a correlation between their molecular properties and bioactivity.

Recent Updates on Free Fatty Acid Receptor 1 (GPR-40) Agonists for the Treatment of Type 2 Diabetes Mellitus.

The global incidence of type 2 diabetes mellitus (T2DM) has enthused the development of new antidiabetic targets with low toxicity and long-term stability. In this respect, free fatty acid receptor 1 (FFAR1), which is also recognized as a G protein-coupled receptor 40 (GPR40), is a novel target for the treatment of T2DM. FFAR1/GPR40 has a high level of expression in β-cells of the pancreas, and the requirement of glucose for stimulating insulin release results in immense stimulation to utilise this target in the medication of T2DM. The data used for this review is based on the search of several scienctific databases as well as various patent databases. The main search terms used were free fatty acid receptor 1, FFAR1, FFAR1 agonists, diabetes mellitus, G protein-coupled receptor 40 (GPR40), GPR40 agonists, GPR40 ligands, type 2 diabetes mellitus and T2DM. The present review article gives a brief overview of FFAR1, its role in T2DM, recent developments in small molecule FFAR1 (GPR40) agonists reported till now, compounds of natural/plant origin, recent patents published in the last few years, mechanism of FFAR1 activation by the agonists, and clinical status of the FFAR1/GPR40 agonists. The agonists of FFAR1/GRP40 showed considerable potential for the therapeutic control of T2DM. Most of the small molecule FFAR1/GPR40 agonists developed were aryl alkanoic acid derivatives (such as phenylpropionic acids, phenylacetic acids, phenoxyacetic acids, and benzofuran acetic acid derivatives) and thiazolidinediones. Some natural/plant-derived compounds, including fatty acids, sesquiterpenes, phenolic compounds, anthocyanins, isoquinoline, and indole alkaloids, were also reported as potent FFAR1 agonists. The clinical investigations of the FFAR1 agonists demonstrated their probable role in the improvement of glucose control. Though, there are some problems still to be resolved in this field as some FFAR1 agonists terminated in the late phase of clinical studies due to "hepatotoxicity." Currently, PBI-4050 is under clinical investigation by Prometic. Further investigation of pharmacophore scaffolds for FFAR1 full agonists as well as multitargeted modulators and corresponding clinical investigations will be anticipated, which can open up new directions in this area.

Adsorption and Electrodegradation of Phenoxyacetic Acids on Various Activated Carbons

Adsorption and Electrodegradation of Phenoxyacetic Acids on Various Activated Carbons

Solid-phase extraction of phenoxyacetic acid herbicides in complex samples with a zirconium(IV)-based metal-organic framework.

A zirconium(IV)-based metal-organic framework material (MOF-808) has been synthesized in a simple way and used for the extraction of phenoxyacetic acids in complex samples. The material has good thermal and chemical stability, large specific surface area (905.36m²/g), and high pore size (22.18Å). Besides, it contains a large amount of Zr-O groups, easy-to-form Zr-O-H bond with carboxyl groups of phenoxyacetic acids, and possesses biphenyl skeleton structure, easy to interact with compounds through π-π and hydrophobic interactions. These characteristics make the material very suitable for the extraction of certain compounds with a high extraction efficiency and excellent selectivity. The extraction conditions were optimized, and then an analytical method was successfully established and applied for analysis of actual samples. The solid-phase extraction method based on prepared material had a wide linear range of 0.2-250μg/L and a low detection limit of 0.1-0.5μg/L for four phenoxyacetic acid compounds including 2,4-dichlorophenoxyacetic acid, 2-(2,4-dichlorophenoxy) propionic acid, 4-chlorophenoxyacetic acid, and dicamba. The relative standard deviations of intra- and interday precision were 1.8-3.8 and 4.3-6.9%, and the recoveries after spiking were between 77.1 and 109.3%. The results showed that the material is a desired substituent for the extraction of compounds with benzene ring structure containing carboxyl groups.

Conversion of 4-Chlorophenoxyacetic Acid by the Pseudomonas sp. 36DCP Strain

The new natural 36DCP strain, which is capable of using 4-chlorophenoxyacetic acid (4-CPA) as the sole source of carbon and energy, was characterized. A culture isolated from a soil sample contaminated with chemical waste was identified according to physiological, biochemical, cultural, morphological features and analysis of the 16S rRNA gene sequence as a strain belonging to the Pseudomonas genus. In the batch culture, Pseudomonas sp. 36DCP degraded 45% of 4-CPA from the initial concentration after 5 days of incubation. Based on the identified intermediate metabolites in the culture medium (para-benzoquinone and hydroquinone), it was found that the conversion of 4-CPA in Pseudomonas sp. 36DCP proceeds through the hydroquinone pathway. This degradation pathway of monochlorinated phenoxyacetic acids has not previously been described in bacteria.

Zirconium(IV)-based metal-organic frameworks (UiO-67) as solid-phase extraction adsorbents for extraction of phenoxyacetic acid herbicides from vegetables.

A zirconium(IV)-based metal organic framework, composed of 4,4'-biphenyldicarboxylic acid ligands and Zr6 O4 (OH)4 clusters, was successfully fabricated. Characterizations were performed on fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller, and thermogravimetric analysis, which confirmed that it possessed large specific surface area, high pore volume, and strong acid resistant stability. Furthermore, the prepared material containing biphenyl skeleton and a large number of Zr-O bonds, can grasp acid herbicides especially phenoxyacetic acid herbicides with aromatic structures through π-π interaction, hydrophobic interaction and Zr-O-H+ bonds. Based on these advantages, a method was developed for the determination of four phenoxyacetic acid herbicides from vegetable samples. Under the optimal conditions, wide linearities from 0.3 to 250 μg/L and low limits of detection from 0.1 to 0.5 μg/L were obtained. The intra- and interday relative standard deviations were 1.56-3.92 and 5.01-7.65%, respectively. The proposed method was applied to analyze phenoxyacetic acid herbicides residues in the tomato, cucumber, and white gourd samples. The satisfactory recoveries (86.12-103.44%) for the spiked samples in vegetable samples were achieved which demonstrated the method was an efficient pretreatment procedure and has a potential application for the trace determination of phenoxyacetic acids from a complex matrix.

Humic acid and biochar as specific sorbents of pesticides

PurposeThe aim of the research was to compare the effect of two types of organic sorbents—humic acid (HA) and biochar (BC)—in sorption-desorption processes of different polar pesticides, which residues are commonly present in arable soils and are potentially harmful for the environment. It also aims to advance the understanding of behavior of both ionizable and nonionizable pesticides in the presence of BC and HA in soils.Materials and methodsThree different classes of pesticides were investigated: carbamates (carbaryl and carbofuran), phenoxyacetic acids (2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA)), and aniline derivatives (metolachlor). Investigated humic acid was extracted by Shnitzer’s method from topsoil horizon of arable Gleyic Phaeozem. Biochar was produced from wheat straw in gasification process at 550 °C, remaining 30 s in the reactor. To obtain the experimental goal structural properties of both sorbents were determined and sorption-desorption experiments conducted. To the investigated organic matter samples (HA or BC), 10 or 15 mg L−1 pesticide solutions in 10 mM CaCl2 were added and the mixtures were shaken for 24 h. Afterwards, the samples were centrifuged and supernatants analyzed by LC-MS/MS for the pesticide content. Analogous experiment was performed for desorption studies (samples refilled with 10 mM CaCl2).Results and discussionHumic acids exhibited strong affinity for the ionic substances, for which high-percentage uptake (74.6 and 67.9% initial dose of 2,4-D and MCPA, respectively) was obtained. Retention of nonionic carbamates on HA was much weaker (35.4% of carbofuran and 10.2% of carbaryl sorbed). Sorption of carbamates to BC was significantly reduced (76.4–84.3%) by the alkaline hydrolysis. Metolachlor was bound comparably strong both by HA (72.9%) and BC (70.2%), although different mechanisms governed its sorption. Noticeable desorption occurred only in the case of 2,4-D bound to HA (over 50%), whereas other studied compounds were released from HA within the range of 4.4–10.8% of the dose sorbed. Oppositely to HA, desorption of all studied pesticides from BC was completely inhibited, except for 2,4-D (3.7% desorbed).ConclusionsInvestigated humic acid has high affinity to polar, ionic pesticides of high water solubility, which are sorbed via specific interactions with HA functional groups. Studied biochar, due to its moderately hydrophobic character, preferentially attracts nonionic pesticides of relatively high logP values and low water solubility. Hydrophobic bonding is postulated as a main mechanism of their attraction to BC. Besides sorbent structural properties, pH is the main factor governing sorption equilibria in the studied mixtures.

Toxicity of thymol, carvacrol and their respective phenoxyacetic acids in Lactuca sativa and Sorghum bicolor

Natural and semisynthetic compounds may be useful to obtain novel herbicides. Thymol and carvacrol, which belong to the class of phenols, are examples of molecules found in the nature that present phytotoxic activity. Thus, we aimed to synthesize phenoxyacetic acids from thymol and carvacrol and to use them in plant bioassays. The thymoxyacetic and carvacroxyacetic acids were obtained from thymol and carvacrol, respectively, in the presence of sodium chloroacetate, under reflux, followed by acidification. These compounds were tested against Lactuca sativa and Sorghum bicolor initial seed development and their effects were tested on L. sativa and S. bicolor DNA. We also evaluated the performance of these compounds in the mitotic cycle of meristematic cells of L. sativa roots. The synthesized compounds were characterized by mass spectrometry and nuclear magnetic resonancespectroscopy (NMR) of 1H and 13C. The compounds were tested in different concentrations regarding the biological assays: 0.0, 0.375, 0.750, 1.50 and 3.0 mmol L−1. After the analysis of the comet assay, carvacrol and carvacroxyacetic acid showed the most damaging effects on L. sativa and S. bicolor DNA. To corroborate the results found for these two compounds, we carried out an analysis with ISSR to verify the molecular damages in the two tested plants. We concluded that carvacrol, thymol, carvacroxyacetic and thymoxyacetic acids presented phytotoxic and cytotoxic activities. Carvacrol and the carvacroxyacetic acid also showed genotoxic action at the concentration of 3.0 mmol L−1. The toxic effect of the thymoxyacetic acid was similar to that of the commercial herbicide 2,4-D, that is, more pronounced in L. sativa (eudicot) than in S. bicolor (monocot).

Synthesis of Amides from Aliphatic Acids and Amines by using of I2/TBHP at Room Temperature

AbstractA novel metal free system of I2/TBHP for coupling of anilines with various acids leading to amidation has been developed. The reaction possibly proceeds via acetic hypoiodous anhydride formation. Besides, the scope of the method was also extended to thioglycolic acid and phenoxy acetic acids. The reaction is easy to set up, involves mild conditions and proceeds efficiently over a wide range of substrates with excellent functional group tolerance.