The Effects Of Humic Substances On Pinus Callus Are Reversed By 2,4-Dichlorophenoxyacetic Acid

The reversal of humic matter-induced inhibition of callus growth and metabolism by 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in Pinus laricio. Two forest humic fractions (relative molecular mass (M_r) > 3500), derived from soil under Fagus sylvatica (Fs) and Abies alba (Aa) plantation, were used. Pinus laricio callus was grown for a subculture period (4 weeks) on Basal Murashige and Skoog (MS) medium plus forest humic matters (Fs or Aa), at a concentration of 1 mg C/l, and then was transferred, for an additional four weeks, to a MS medium culture without humic matter, but with different hormones: indole-3-acetic acid (IAA, 2 mg/1) or 2,4-dichlorophenoxyacetic acid (2,4-D, 0.5 mg/1) and/or 6-benzylaminopurine (BAP, 0.25 mg/1). Growth of calluse, glucose, fructose, and sucrose contents, and activities of soluble and bound invertases, glucokinase, phosphoglucose isomerase, aldolase, and pyruvate kinase were monitored. The results show a negative effect of humic fractions on callus growth, due to decreased utilization of glucose and fructose, and decreased activities of glycolytic enzymes. The effects are reversible. Substitution of humic fractions with 2,4-D+BAP or 2,4-D is followed by an increase of glycolytic enzyme activities and, consequently, by the utilization of glucose and fructose that induces a restart of growth. In contrast, the inhibitory effects of humic fractions persist when they are substituted with BAP alone, indicating that only the auxin 2,4-D is capable of reversing the negative effects. A possible competitive action on the auxin-binding site between 2,4-D and the chemical structures in the forest humic fractions is suggested.     

Photocatalyzed Degradation of Phenol, 2,4-Dichlorophenol,Phenoxyacetic Acid and 2,4-Dichlorophenoxyacetic Acid over SupportedTiO2 in a Flow System

The photodegradation of phenol, 2,4-dichlorophenol, phenoxyacetic acid and 2,4-dichlorophenoxyacetic acid using TiO₂ as photocatalyst is investigated. The photodegradations of these compounds have been conducted in a continuous mode by means of a flow system, in which TiO₂ remains fixed onto glass pearls. The use of this system gives high yields of degradation for the chemicals tested, except for 2,4-dichlorophenol for which a slow dechlorination process is observed. The rate of photodegradation depends on the pH of the solution, the point of zero charge of TiO₂ and the pK_a of the chemicals being the key parameters. The main aromatic intermediates detected have been hydroquinone,paraquinone and hydrohydroquinone during phenol degradation; phenol and hydroquinone during phenoxyacetic acid degradation; chlorohydroquinone and chlorophenol during 2,4-dichlorophenol degradation; and dichlorophenol during 2,4-dichlorophenoxyacetic acid degradation. Finally, some long term irradiations with phenol as model compound have been performed, showing high degrees of photodegradation. It has been observed that only a periodic evacuation of the effluent out of the reactor is needed to sustain high percentages of photodegradation.     

Formation of red pigment by a two-step 2-thiobarbituric acid reaction of alka-2,4-dienals. Potential products of lipid oxidation

Reaction of 2,4-hexadienal, 2,4-nonadienal and 2,4-decadienal with 2-thiobarbituric acid (TBA) in aqueous acetic acid produced a 532-nm absorbing red pigment. While the 1∶1 reaction of the aldehyde and TBA produced little pigment, reaction of the aldehyde with an excess amount of TBA produced significant amounts. Instant heating of the reaction mixture did not produce the pigment. However, initial reaction at 5°C and subsequent heating to 100°C produced the pigment efficiently (two-step reaction). Pigment formation required water and dissolved oxygen. The yield of the pigment from the alka-2,4-dienals was 1/10–1/20 of that from malonaldehyde. In the first step of the reaction at 5°C, the 1∶1 adducts of the aldehydes at the5-position of TBA and several other uniden-tified adducts were formed. In the second step, these adducts were converted at 100°C, in the presence of water and oxygen, into the red pigment. The structure of the red pigment from 2,4-hexadienal was elucidated to be the 1∶2 adduct of malonaldehyde and TBA. 2-Hexenal andt-butylhydroperoxide showed marked synergistic effects on the pigment formation from the alka-2,4-dienals. Red pigment formation due to the alka-2,4-dienals may be enhanced by the presence of other aldehydes and hydro-peroxides.     

Adhesive properties of cured epoxide resin containing the intermolecular compound of 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid

The intermolecular compound of 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid was synthesized, and the glass transition temperature and the adhesive properties of the cured epoxide resin containing the above compound were studied. Epoxide reacted with amino groups of 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid at the curing conditions of 150 to 180°C for 60 min and formed the cured compounds. The infrared spectra showed that epoxide reacted with isocyanuric acid in the presence of imidazole compounds and converted to 2-oxazolidinone compound on the curing process. The glass transition temperatures of the cured compounds having isocyanurate and 2-oxazolidinone rings in their structures were higher than that of the epoxide resin cured with imidazole and rise as the curing temperature rises, but fall as 2-oxazolidinone ring content increases in their cured compounds. The tensile shear and peel strengths of the steel and steel bonded with the cured compounds and the cured epoxide resin were measured at 25 and 150°C. The adhesive strengths were improved due to isocyanurate and 2-oxazolidinone rings formed in their cured compounds.     

H3PW12O40 Supported on AlMCM-41 molecular sieves: An effectual catalyst for t-butylation of anisole

Mesoporous AlMCM-41 (Si/Al = 25) molecular sieves was synthesized and impregnated with different loadings (10, 20 and 30 wt% H₃PW₁₂O₄₀) of phosphotungstic acid. Their catalytic performance was examined in the vapour phase alkylation of anisole with tert-butanol. The major products were found to be 2-tert-butyl anisole (2-TBA), 4-tert-butyl anisole (4-TBA), 2,4-di-tert-butyl anisole (2,4-DTBA). 4-TBA was the major product formed with high selectivity. The influence of temperature, feed ratio, WHSV was studied and the results are discussed.     

The Conversion of 2,4-Dinitrophenylhydrazine derivatives of monocarbonyls to ethylenethioacetals and ethylenethioketals for analysis by gas liquid chromatography

A method was developed for the direct conversion of 2,4-dinitrophenylhydrazones (2,4-DNPHS) ofn-al-kanals and methylketones int ethylenethioacetals and ethylenethioketals for analysis by gas liquid chromatography (GLC). the method depended on heating the 2,4-DNPHS and 1,2-ethanedithiol with boron fluoride (BF₃) ethyl ether at 125 C for 12 min or withp-toluenesulfonic acid at 200 C for 15 min. The reaction was extracted with pentane, and after evaporation, the product was dissolved ono-cylene and injected into the GLC. High yields of above 90% were obtained from long chain 2,4-DNPHS and somewhat lower yields of about 80% were obtained from short chain 2,4-DNPHS. Eight standard ethylenethioacetals and ethylenethioketals were synthesized; their elemental analysis, bp, mp, and retention times on FFAP and SE-30 GLC columns were determined.     

Controlled release of polymer conjugated agrochemicals. System based on poly(methyl vinyl ether‐alt‐maleic anhydride)

Controlled release formulations were prepared by using commercially available poly(methyl vinyl ether‐alt‐maleic anhydride) (I) and 2,4‐dichlorophenoxy acetic acid herbicide (2,4‐D). The copolymer (I) was reacted with various diamines to produce amido‐amine containing carboxylate copolymers. The produced copolymers were reacted with the acid chloride of herbicide 2,4‐D as model herbicide for carboxylic group functionalized herbicides. The formulations produced were characterized by IR and elemental analyses. The release of the herbicide 2,4‐D from the formulations was studied under different aqueous medium conditions and the effect of copolymer microstructure on release profiles was investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 415–421, 2001     

Preparation of 2,4-dichlorophenoxyacetic acid loaded on cysteamine-modified polydopamine and its release behaviors

With dopamine as the monomer, the model pesticide 2,4-dichlorophenoxyacetic acid (2,4D) was loaded on cysteamine (NHSH)-modified polydopamine (PDA) nanospheres [2,4-dichlorophenoxyacetic acid bound to cysteamine-modified polydopamine (2,4D–PDA–NHSH)] via the construction of amide bonds. We investigated the materials’ structure, adhesive capability, and release behaviors, especially the mechanism of the release processes. The results demonstrate that the materials were spherical in appearance and adhesive. 2,4D loaded on the PDA vehicle was amorphous in structure. The amide bond between PDA and 2,4D generated by NHSH not only enhanced the loading amount of PDA from 296.28 to 692.56 mg/g but also decreased the thermal stability from 291 to 230 °C. The 2,4D–PDA–NHSH showed no pH responsiveness, whereas the PDA system without NHSH modification exhibited pH sensitivity. A mechanism for the observed behaviors was suggested. First-order, logistic, Weibull, and Korsmeyer–Peppas models were applied to describe the release behaviors at different pH values. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47469.     

An ecologically effective water treatment technique using electrochemically generated hydroxyl radicals for in situ destruction of organic pollutants: Application to herbicide 2,4-D

The electrochemical production of Fenton's reagent by simultaneous reduction of dioxygen and ferric ions on a carbon felt electrode, permits a controlled, in situ generation of hydroxyl (OH^·) radicals. The possibility of using electrochemically produced OH radicals for solving environmental problems is investigated. Continuous and controlled production of hydroxyl radicals was achieved by electrochemical reduction of O₂ in the presence of a catalytic amount of ferric or ferrous ion. These radicals are used for remediation of water containing toxic-persistent-bioaccumulative organic pollutants through their transformation into biodegradable compounds or through their mineralization into H₂O and CO₂. A widely used herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), was selected as a model for a toxic organic pollutant. High pressure liquid chromatography (HPLC) was used to quantify the distribution of the hydroxylated products obtained. Rate constants for the hydroxylation reactions of 2,4-D, 2,4-dichlorophenol (2,4-DCP), 2,4-dichlororesorcinol (2,4-DCR) and 4,6-dichlororesorcinol (4,6-DCR) were determined. The mineralization of 2,4-D and its derivatives was followed by total organic carbon (TOC) measurements. More than 95% of 2,4-D and the intermediates generated during the electrolysis can be mineralized.     

Effects of Linalyl Oleate on Soybean Oil Flavor and Quality in a Frying Application

Bread pieces were fried at 180 °C in soybean oil (SBO) containing no additives (control), 0.1% linalyl oleate (LO), or 10 ppm methyl silicone (MS). After 2 h of heating, the MS-containing oil was the most stable, followed by the oil with LO and the control, based on conjugated dienoic acid percentage (CD) and the ratio of linoleate%/palmitate%. Oil extracted from the fresh fried bread showed similar, but not significant, trends for CD and PV. Fresh and stored (60 °C, 2 days) bread fried in LO-containing oil had less hexanal than the other two treatments, and the stored LO bread had less t,c- and t,t-2,4-heptadienal than the control. Fresh bread fried in LO-containing oil had a less rancid flavor than did the other two treatments, and the LO treatment had less fishy flavor than the control. In stored bread, the MS treatment was less rancid than the control. In oil extracted from the stored bread, the amounts of t,c-2,4-heptadienal and 2-decenal correlated (p ≤ 0.05) with the amounts of individual unsaturated fatty acids and with CD, but only t,c-2,4-heptadienal correlated with the PV. The t,c-2,4-heptadienal correlated with individual Polyunsaturated fatty acids (PUFA) in freshly fried bread. In general, oil and fried bread had improved flavor quality and/or oil stability when they contained MS or LO.     

Synthesis and antimicrobial evaluation of some pyrazolo-thiazolyl alkoxy-1H-isoindole-1, 3(2H)-dione derivatives

1,3-Thiazolidine-2,4-dione 2 has been synthesized by the cyclisation reaction of thiourea and chloroacetic acid in the presence of ethanol. The reaction of compound 2 with substituted aromatic aldehyde afforded the corresponding derivatives of substituted 5-benzylidene-1,3-thiazolidinone-2,4-dione 3a–d, which upon reflux with ω-bromoalkoxyphthalimide gave 2-{[-5-(substituted benzylidine)-2,4-dioxo-1,3-thiazolidine-3-yl]alkoxy} -1H-isoindole-1,3(2H)-dione 4a–i. Further, compounds 4a–i were treated with phenyl hydrazine and 2,4 dinitro phenyl hydrazine in the DMF to yield the title compound 2-[5-oxo-2,3-substituted diphenyl-2H-pyrazolo[3,4-d][1,3]thiazol-6(5H)-yl)alkoxy]-1H-isoindole-1,3(2H)-dione 5a–r. Structures of newly synthesized compounds were established based on elemental analysis, IR, ¹H NMR and mass spectral data. Synthesized compounds have been assayed for their antibacterial activities against B. subtilis, K. pneumoniae, P. aeruginosa and S. aureus and antifungal activities against A. fumigatus and C. albicans.     

One-pot photoinduced synthesis of dansyl containing acrylamide hydrogels and their chemosensing properties

Novel fluorescent acrylamide hydrogel containing dansyl moiety (DNS-gel) was synthesized via free-radical photopolymerization of acrylamide/N,N′-methylenebisacrylamide by using dansyl chloride as a photoinitiator. DNS-gel presented dual-fluorescence emission when excited at 344 nm in acetonitrile:water (1:1) solvent system due to twisted intramolecular charge transfer between dimethylamino and naphthalene units in the dansyl moiety. Synthesized fluorophore containing gel was utilized as a fluorescent sensor against specific metal ions (Pb²⁺, Hg²⁺, Co²⁺, Cd²⁺, Mn²⁺, and Zn²⁺) and nitroaromatic compounds [1,2-dinitrobenzene, 2,4,6-trinitro-1-phenol [picric acid (PA)], 4-nitrophenol, 2,4,6-trinitrotoluene, 2,4-dinitrophenol (2,4-DNP), and 2-nitrotoluene]. Fluorescence intensity of DNS-gel was diminished by degrees upon the infusion of metal ions and nitroaromatics. For all compounds, the greatest quenching effectiveness was attained in the presence of Co²⁺ (72.56%), PA (88.55%), and 2,4-DNP, suggesting that DNS-gel could be employed as a potential Co²⁺, PA, and 2,4-DNP chemical probes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47096.     

Synthesis of Diuloses by Chain Elongation of Aldonoyl Chlorides

2,3,4,5,6-Penta-O-acetyl-D -galactonic acid chloride ( 1a ) and D -gluconic acid chloride ( 1b ), respectively, react with alkyl acetoacetates and benzoylacetates 2 , respectively, to yield derivatives 3 of diuloses with an alkoxycarbonyl group in the branch. Decarboalkoxylation of these compounds gives 1,3-didesoxy-nono-2,4-diuloses 4a,b and 2-deoxy-octo-1,3-diuloses 4c , respectively. Compound 4a and diazomethane react to furnish the corresponding methyl enol ether 5a and 5b .     

Synthesis,Crystal Structure and Luminescence Property of a New (6,3)-Connected Zn(II) Coordination Polymer

The 2D coordination polymer, [Zn(dpa)(bpp)] _n (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, bpp = 1,3-di(4-pyridyl)propane) was prepared by hydrothermal synthesis in the presence of NaOH and characterized by single-crystal X-ray diffraction, FTIR spectra, element analysis and thermal analysis. The crystal structure determination reveals that the carboxylate groups of 2,4′-biphenyldicarboxylic acid are acting as bridging ligands and adopt two coordination modes; bis-monodentate and bidentate chelating. The network consists of a 2D (6,3)-connected architecture. At room temperature the solid-state luminescence spectrum of [Zn(dpa)(bpp)] _n shows a blue emission at about 354 nm upon excitation at 333 nm.     

Structure–Activity Relationships of Benzoic Acid Derivatives as Antifeedants for the Pine Weevil, Hylobius abietis

Aromatic organic compounds found in the feces of the pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), have been shown to deter feeding behavior in this species, which is a serious pest of planted conifer seedlings in Europe. We evaluated 55 benzoic acid derivatives and a few homologs as antifeedants for H. abietis. Structure–activity relationships were identified by bioassaying related compounds obtained by rational syntheses of functional group analogs and structural isomers. We identified five main criteria of efficiency as antifeedants among the benzoic acid derivatives. By predicting optimal structures for H. abietis antifeedants, we attempted to find a commercial antifeedant to protect conifer seedlings against damage by H. abietis in regenerating forests. New, highly effective antifeedants are methyl 2,4-dimethoxybenzoate, isopropyl 2,4-dimethoxybenzoate, methyl 2-hydroxy-3-methoxybenzoate, methyl (3,5-dimethoxyphenyl)acetate, and methyl (2,5-dimethoxyphenyl)acetate. Of these, methyl 2,4-dimethoxybenzoate and isopropyl 2,4-dimethoxybenzoate have the highest antifeedant indices of all substances tested and are the best candidates for practical applications in order to protect planted seedlings in the field.     

Use of labeled compounds to study the mechanism of flavor formation in oxidizing fats

2-¹⁴C-Hexanal,trans, trans-5-¹⁴C-2,4-decadienal, 4-¹⁴C-1-octen-3-ol, 4-¹⁴C-1-octen-3-one and 1-¹⁴C-1-pentanol were synthesized and added to freshly deodorized soybean oil in concentrations ranging from 7–125 ppm. The soybean oil was oxidized, and the fate of the labeled compounds was followed. Hexanal was converted to hexanoic acid especially at 50 C or higher. The 2,4-decadienal was converted to 2,4-decadienoic acid at room temperature, and heptenal, 2-octanal, 2-nonanal, glyoxal and malonaldehyde were found among the labeled products. 1-Octen-3-ol was converted to 1-octen-3-one at room temperature, but the 1-octen-3-one formed a stable end product that produced no other labeled compounds. 1-Pentanol was converted to pentanoic acid at 50 C or higher. One of 13 papers presented in the symposium “Flavor Research in Fats and Fat Bearing Foods,” AOCS Meeting, Atlantic City, October 1971. Journal Paper No. J-7082 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa 50010. Project 1856.     

2,4-二氯-5-磺酰氨基苯甲酸合成工艺研究

2,4-二氯苯甲酸为原料,经氯磺化、氨解、水解酸化三步反应制备了2,4-二氯-5-磺酰氨基苯甲酸(1)。研究了各步反应的影响因素,确定反应的最佳工艺为:n(氯磺酸)∶n(2,4-二氯苯甲酸)=3.5∶1,反应温度为130～140°C,反应时间为3.5h。得产品2,4-二氯-5-磺酰氨基苯甲酸(2)。n(氨水)∶n(2)=4∶1,10～15°C反应3h,盐酸酸化,得到(1),总收率79.3%,纯度98.7%(HPLC),结构经IR与1H NMR证实。     

Synthesis of Novel Pyridine-Carboxylates as Small-Molecule Inhibitors of Human Aspartate/Asparagine-β-Hydroxylase

The human 2-oxoglutarate (2OG)-dependent oxygenase aspartate/asparagine-β-hydroxylase (AspH) is a potential medicinal chemistry target for anticancer therapy. AspH is present on the cell surface of invasive cancer cells and accepts epidermal growth factor-like domain (EGFD) substrates with a noncanonical (i. e., Cys 1–2, 3–4, 5–6) disulfide pattern. We report a concise synthesis of C-3-substituted derivatives of pyridine-2,4-dicarboxylic acid (2,4-PDCA) as 2OG competitors for use in SAR studies on AspH inhibition. AspH inhibition was assayed by using a mass spectrometry-based assay with a stable thioether analogue of a natural EGFD AspH substrate. Certain C-3-substituted 2,4-PDCA derivatives were potent AspH inhibitors, manifesting selectivity over some, but not all, other tested human 2OG oxygenases. The results raise questions about the use of pyridine-carboxylate-related 2OG analogues as selective functional probes for specific 2OG oxygenases, and should aid in the development of AspH inhibitors suitable for in vivo use.     

Specific determination of malonaldehyde by N-methyl-2-phenylindole or thiobarbituric acid

Reactivity of a commercially available test kit (LPO-586), based on N-methyl-2-phenylindole, toward aldehydes was characterized and compared with that of thiobarbituric acid (TBA). In hydrochloric acid, LPO-586 produced a violet pigment with malonaldehyde (MA) but not with other tested aldehydes. In methane sulfonic acid, LPO-586 produced the violet pigment with MA and 4-hydroxynonenal (HNE), but not with other tested aldehydes. Pigment formation with MA was not inhibited by other aldehydes, but that with HNE was inhibited by alka-2,4-dienals. TBA produced a red pigment with MA but not with other tested aldehydes in hydrochloric acid or in acetate with ethylenediaminetetraacetic acid (EDTA). Both the LPO-586 test in hydrochloric acid and the TBA test in hydrochloric acid or in acetate with EDTA can be used for specific measurement of MA in oxidized lipid samples.     

Adsorption of 2,4-D onto activated carbon: Application of Nth order approximation

Adsorption kinetics of 2,4-dichlorophenoxyacetic acid (2,4-D) onto activated carbon is presented in this paper. The equilibrium adsorption of 2,4-D is described by a Freundlich type isotherm and the batch kinetic experiments are analysed using a surface diffusion model. The model equations are simplified by an nth order approximation and, when applied to the experimental data, the approximation predicted the film transfer and diffusion coefficients with a good accuracy.