Metabolism of 2,4-dinitrotoluene and 2,6-dinitrotoluene, and their dinitrobenzyl alcohols and dinitrobenzaldehydes by Wistar and Sprague-Dawley rat liver microsomal and cytosol fractions

The metabolism of 2,4-dinitrotoluene (2,4-DNT), 2,4-dinitrobenzyl alcohol (2,4-DNB), 2,4-dinitrobenzaldehyde (2,4-DNBAl), 2,6-DNT, 2,6-DNB and 2,6-DNBAl in the microsomal and cytosol fractions prepared from unfortified male Wistar and male Sprague-Dawley (S.D.) rat livers was investigated. Data obtained by high-performance liquid chromatography (HPLC) indicated that the products of dinitrotoluenes (2,4-DNT and 2,6-DNT), dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB), and dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl) in the microsomal and cytosol preparations containing nicotinamide adenine dinucleotide phosphate (NAD(P] and reduced NAD(P)(NAD(P)H) were dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB), dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl), and dinitrobenzoic acids (2,4-DNBA and 2,6-DNBA), and dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB), respectively. From these results, it was concluded that the dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl) were intermediates in the oxidations of dinitrobenzyl alchols (2,4-DNB and 2,6-DNB) to dinitrobenzoic acids (2,4-DNBA and 2,6-DNBA), and that the oxidations of dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB) to dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl) and the reductions of dinitrobenzaldehydes to dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB) were reversible.(ABSTRACT TRUNCATED AT 250 WORDS)     

Optimizing Separation Conditions for Chlorophenoxycarboxylic Acid Herbicides in Natural and Potable Water Using Capillary Zone Electrophoresis

Chlorophenoxycarboxylic acid herbicides were separated and determined by capillary electrophoresis. An analysis of a six-component mixture containing 2,4-dichlorophenoxybutyric (2,4-DB), 2,4-dichlorophenoxypropionic (2,4-DP), 2,4,5-trichlorophenoxyacetic (2,4,5-T), 2,4-dichlorophenoxyacetic (2,4-D), and phenoxyacetic (PA) acids and 2,4-dichlorophenol (2,4-DCP), the product of their degradation in aqueous media, took no longer than 15 min. Solid-phase extraction on Diapak C-16 cartridges was used for sample preparation. The detection limits for herbicides in water samples with account for preconcentration (K = 250) were found to be 0.0005 mg/L for 2,4-DB, 2,4-DP, 2,4,5-T, and 2,4-D and 0.001 mg/L for PA. It was shown that humic acids (< 50 mg/L) do not interfere with the determination of chlorophenoxycarboxylic acids.     

2,4-Pentanediolate as an alkoxide/diketonate "hybrid" ligand and the formation of aluminum and zirconium derivatives

When 2,4-pentanediol (2,4-H(2)pd) is deprotonated, the resulting dianion (2,4-pd) serves as a type of "hybrid" ligand, i.e., an alkoxide that possesses structural features of a β-diketonate. 2,4-Pentanediol reacts with Al(O-s-Bu)(3) and Zr(O-i-Pr)(4) to form chelated multinuclear complexes. The aluminum-containing product is first isolated as the insoluble [Al(2,4-pd)(2,4-Hpd)](n); on sublimation, a hydrocarbon-soluble mixture of polymetallic species is generated. Mass spectral evidence suggests that both Al(4)(2,4-pd)(6) and Al(5)(2,4-pd)(7)(2,4-Hpd) are present. The zirconium complex is isolated as an adduct, [Zr(2,4-pd)(2)](2)·(2,4-H(2)pd). The pentanediolates decompose on heating to form Al(2)O(3) and ZrO(2). Unlike the mononuclear Al(acac)(3) and Zr(acac)(4) derivatives (acac = acetylacetonate), the formation of aggregates with the 2,4-pd ligand suggests that the latter has more coordinative flexibility. The geometries of several model aluminum complexes with oxygen donor ligands were studied with density functional theory methods. The optimized structures were used with the gauge, including atomic orbital (GIAO) method to calculate their (27)Al NMR magnetic shielding values for comparison with experiment.     

Reaction of 3,4,6-trioxoalkanoic acid esters with 2,4-dinitrophenylhydrazine

Methyl 3,4,6-trioxoalkanoates (3,4-dihydroxy-6-oxo-2,4-alkadienoates) reacted with 2,4-dinitrophenylhydrazine to give methyl 3,6-bis[(2,4-dinitrophenyl)hydrazinylidene]-4-oxoalkanoates or methyl {5-alkyl-2-hydroxy-1-(2,4-dinitroanilino)-3-oxo-2,3-dihydro-1H-pyrrol-2-yl }acetates. Alkyl 3,6-bis[(2,4-dinitrophenyl) hydrazinylidene]-4-oxoalkanoates were also synthesized by reaction of disodium 1-alkoxy-1,6-dioxoalka-2,4-diene-3,4-diolates with 2,4-dinitrophenylhydrazine.     

Synthesis of chiral hydrazine reagents and their application for liquid chromatographic separation of carbonyl compounds via diastereomer formation

Five new chiral derivatizing reagents 5-hydrazino-2,4-dinitrophenyl-l-alaninamide (HDNP-l-Ala-NH2), 5-hydrazino-2,4-dinitrophenyl-l-phenylalaninamide (HDNP-l-Phe-NH2), 5-hydrazino-2,4-dinitrophenyl-l-valinamide (HDNP-l-Val-NH2), 5-hydrazino-2,4-dinitrophenyl-l-leucinamide (HDNP-l-Leu-NH2) and 5-hydrazino-2,4-dinitrophenyl-l-phenylglycinamide (HDNP-d-Phg-NH2) were synthesized by straightforward two-step synthesis starting from 1,5-difluoro-2,4-dinitrobenzene. Nucleophilic substitution of one fluorine atom in DFDNB with different amino acid amides yielded Marfey's reagent (5-fluoro-2,4-dinitrophenyl-l-alaninamide) and its structural variants (5-fluoro-2,4-dinitrophenyl-l-phenylalaninamide, 5-fluoro-2,4-dinitrophenyl-l-valinamide, 5-fluoro-2,4-dinitrophenyl-l-leucinamide and 5-fluoro-2,4-dinitrophenyl-d-phenylglycinamide). Chiral hydrazine reagents were prepared by nucleophilic substitution of remaining fluorine atom in Marfey's reagent and its variants with hydrazine under basic conditions. These reagents react quantitatively with chiral carbonyl compounds under mild conditions (30 degrees C, 30 min) to form hydrazone diastereomers. The labeling reaction occurs only in the presence of acid which has a catalytic action and diastereomers have strong absorbance around 348 nm. The separation of diastereomers was tried on a reversed-phase C18 HPLC column using different binary solvent combinations. Excellent separation was achieved in case of cyclic ketones having substitution at alpha-position. Optimization for derivatization yield, limit of detection, limit of quantification, linearity, accuracy and precision was carried out with respect to HDNP-l-Val-NH2. Studies related to effects of structural modification in reagents and analytes on chromatographic behavior of diastereomers were also analyzed.     

Structure of chlorinated poly(vinyl chloride). XII. Configuration and reactivity of low-molecular-weight models of poly(vinyl chloride) in the course of chlorination

The chlorination of poly(vinyl chloride) (PVC) was investigated by means of low-molecular-weight models of PVC—a dimer and trimer of PVC, viz., 2,4-dichloropentane (2,4-DCP) and 2,4,6-trichloroheptane (2,4,67-TCH). Chlorinations of stereoisomeric mixtures of 2,4-DCP and 2,4,6-TCH have revealed that the d,1 form of 2,4-DCP (syndio-2,4-DCP) is more reactive in the chlorination than the meso form of 2,4-DCP (iso-2,4-DCP), while in the case of the chlorination of 2,4,6-TCH the reactivity of stereoisomers decreases in the order iso-> hetero->syndio-2,4,6-TCH; consequently, analogous structures of stereoisomers of 2,4-DCP and 2,4,6-TCH react in a reverse order and not in the same one. The qualitative order of reactivities of stereoisomers may be correlated formally with the magnitude of their dipole moments. The reactivity of stereoisomers of 2,4-DCP and 2,4,6-TCH decreases with increasing dipole moment.     

Alkylation of Pyrimidine Derivatives with Chloroacetic Acid Esters

Alkylation of 6-methyluracil, 5-hydroxy-6-methyluracil, and 6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-ylammonium sulfate with isopropyl and ethyl chloroacetates afforded previously unknown alkyl 2-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)acetates, alkyl 2-(1-alkoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-3-yl)acetates, 1,3-bis(alkoxycarbonylmethyl)-6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-ylammonium sulfates, and alkyl 2-[1,3-bis(alkoxycarbonylmethyl)-6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yloxy]acetates.     

2,4-二氯苯酚的电化学氧化降解反应研究

采用循环伏安法和原位红外光谱技术研究了2,4-二氯苯酚在Pt电极上的电化学氧化降解反应,结合Fukui函数值预测了2,4-二氯苯酚在电化学氧化过程中的反应位点. 结果表明,Pt电极对2,4-二氯苯酚有良好的电催化活性,2,4-二氯苯酚在电极表面反应主要有3个途径：直接通过电化学反应脱去氯离子,生成苯酚;在·OH的进攻下,C—Cl键断裂,4位Cl较2位Cl先脱去,生成苯二酚,并可进一步氧化生成苯醌以及不饱和羧酸;在·OH的进攻下发生苯环开环反应,生成含氯不饱和羧酸. 在1700 mV左右,2,4-二氯苯酚可经电化学氧化生成CO₂.     

Synthesis and study of a sorbent based on silica gel modified with hyperbranched poly(dichloromethylsilylpropyl)carbosilane with molecular imprints of 2,4-dichlorophenoxyacetic acid

A new sorbent for selective sorption of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solutions—silica gel modified with hyperbranched poly(dichloromethylsilylpropyl)carbosilane with molecular imprints of 2,4-D (SG-MI)—has been synthesized, and its specific surface area has been estimated. Sorption of 2,4-D has been studied under static conditions. Analysis of sorption isotherms shows that SG-MI is capable molecular recognition of 2,4-D. The selectivity of the sorbent synthesized was estimated for structurally related compounds.     

Synthesis of 2,4-diphenyl-1H-pyrrol-1-amine derivatives

The direction of the reaction of 4-bromo-1,3-diphenyl-2-buten-1-one (γ-bromodypnone) with hydrazines depends on the nature of the substituent they contain. Reaction with 1-methylhydrazinium hydrosulfate gives 1-methyl-3,5-diphenylpyridazin-1-ium bromide but carboxylic acid hydrazides give N-(2,4-diphenyl-1H-pyrrol-1-yl)carboxylic acid amides. γ-Bromodypnone and phenylhydrazine give both 1,3,5-triphenyl-1,4-dihydropyridazine and N,2,4-triphenyl-1H-pyrrol-1-amine (15%). 1-(2,4-Dinitrophenyl)hydrazine gives the 2,4-dinitrophenylhydrazone of (Z)-4-bromo-1,3-diphenyl-2-buten-1-one. Condensation of 2,4-diphenyl-1H-pyrrol-1-amine with aromatic aldehydes readily leads to N-(arylmethylidene)-2,4-diphenyl-1H-pyrrol-1-amines and alkylation with methyl iodide gives N,N-dimethyl-2,4-diphenyl-1H-pyrrol-1-amine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–414, March, 2009.     

The roughened silver–palladium cathode for electrocatalytic reductive dechlorination of 2,4-Dichlorophenoxyacetic acid

The roughened silver–palladium (Pd/Ag(r)) electrode was fabricated by a convenient metallic replacement reaction, and its electrocatalytic property towards reductive dechlorination of 2,4-Dichlorophenoxyacetic acid (2,4-D) in basic aqueous solution have been evaluated. Experimental evidence is presented that Pd/Ag(r) exhibited powerful electrocatalytic activity for dechlorination of 2,4-D. In addition, a new dechlorination mechanism of 2,4-D was proposed, in which the formation of adsorbed 2,4-D on Ag is a key step.     

Novel and versatile reactions of trifluoroamine oxide: a new route to polyfluorinated ethers

A series of pyrimidine methyl and polyfluoroalkyl ethers were synthesized from the reactions of trifluoroamine oxide (1) with several 5-substituted uracils in the presence of tetrabutylammonium hydroxide and methanol, 2,2,2-trifluoroethanol (6), or 1H,1H-pentafluoropropanol (7). With 5-(trifluoromethyl)uracil (2), the new ethers formed were 5-fluoro-5-(trifluoromethyl)-6-methoxypyrimidine-2,4-dione (8), 5-fluoro-5-(trifluoromethyl)-6-(trifluoroethoxy)pyrimidine-2,4-dione (9), and 5-fluoro-5-(trifluoromethyl)-6-(1H,1H- pentafluoropropoxy)pyrimidine-2,4-dione (10). With 5-chlorouracil (3), the new ethers 5-chloro-5-fluoro-6-methoxypyrimidine-2,4-dione (11), 5-chloro-5-fluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (12), and 5-chloro-5-fluoro-6-(1H,1H-pentafluoropropoxy)pyrimidine-2,4-dione (13) were obtained. With 5-fluorouracil (4), the new ethers 5,5-difluoro-6-methoxypyrimidine-2,4-dione (14), 5,5-difluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (15) and 5,5 difluoro-6-(1H,1H-pentafluoropropoxy)pyrimidine-2,4-dione (16) were found. By reaction of 5-nitrouracil (5), the new ethers 5-nitro-5-fluoro-6 methoxypyrimidine-2,4-dione (17), 5-nitro-5-fluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (18), and 5-nitro-5-fluoro-6-(1H,1H-pentafluoropropoxy)pyrimidine-2,4-dione (19) were obtained. Each of the new compounds was characterized by using IR, 19F and 1H NMR, and mass spectroscopy, and elemental analysis. A single-crystal X-ray diffraction study of 8 was helpful in confirming compound structure.     

Herbizide,VI [1] kernfluorierte 2,4-dianilino-6-(dihexylamino)-1,3,5-triazine

The nucleophilic substitution of the chlorine atoms in 2,4-dichloro- 6-(dihexylamino)-1,3,5-triazine by aniline leads to 2,4-dianilino-6-(dihexylamino)- 1,3,5-triazine and by fluorinated amines to (dihexylamino)- 1,3,5-triazines bearing groupings as follows: (2-fluoroanilino)-, (3-fluoroanilino)-, (4-fluoroanilino)-, (2,4-difluoroanilino)-, (2,5-difluoroanilino)-, and (2,6-difluoroanilino)-. The new compounds are characterized by IR, ¹-NMR, and mass spectroscopy. 2,4-Bis-(2,4-difluoroanilino)- 6-(dihexylamino)-1,3,5-triazine in particular shows herbicidal and anti- diabetic activity.     

2, 4-二卤代高立方烷的合成

高立方烷-2, 4-二羧酸(1)通过Barton脱羧氯化反应, 可合成出2, 4-二氯高立方烷(3); 而通过改进的Hunsdiecker反应, 则可分别合成出2, 4-二溴高立方烷(4)和2, 4-二碘高立方烷(5)。     

中空纤维三相液相微萃取-高效液相色谱法测定环境水样中7种苯氧羧酸类除草剂

建立了利用中空纤维三相液相微萃取-高效液相色谱联用技术(HF-LPME-HPLC)同时测定环境水中痕量麦草畏(dicamba)、氟草烟(fluroxypyr)、4-氯苯氧乙酸(4-CPA)、2甲4氯(MCPA)、2,4-滴(2,4-D)、2,4-滴苯氧丁酸(2,4-DB)和2甲4氯苯氧丁酸(MCPB)等7种苯氧羧酸类除草剂的分析方法。考察了萃取剂﹑接受相和给出相pH值、萃取时间﹑搅拌速度和盐效应等对检测的影响,通过正交试验优化萃取条件,得到的最佳萃取条件为正辛醇作萃取剂,给出相pH为3,接受相pH为12,萃取30 min,搅拌速度400 r/min。结果表明7种除草剂在较宽的线性范围内线性良好,相关系数为0.9953～0.9988,检出限(信噪比为3)为0.2～1.0 μg/L,富集倍数为76.7～121,加标回收率为68%～104%,相对标准偏差为3.2%～8.1%。该法灵敏度高、操作简单、检测快速、有机溶剂消耗少,为环境水样中痕量苯氧羧酸类除草剂残留的分析提供了有益的参考。     

New microporous coordination polymer affording guest-coordination sites at channel walls

Utilization of a metalloligand, ([Cu(2,4-pydca)2(H2O)].2Et3NH) (1) (2,4-pydca = pyridine-2,4-dicarboxylate), as a building unit provides a novel porous coordination polymer, ([ZnCu(2,4-pydca)2(H2O)3(DMF)].DMF)n (2), in which the Zn(II) ion at the node of the network acts as a linker and the Cu(II) ion in the channel wall is available for guest-coordination.     

Fortuneanosides G-L, dibenzofuran glycosides from the fruit of Pyracantha fortuneana

Six new dibenzofuran glycosides, fortuneanosides G (1), H (2), I (3), J (4), K (5), and L (6), were isolated from the fruit of Pyracantha fortuneana (MAXIM) LI. Their structures were determined to be 3,7-dihydroxy-2,4-dimethoxy-dibenzofuran 7-O-beta-D-glucopyranoside, 3,7-dihydroxy-2,4-dimethoxy-dibenzofuran 7-O-(alpha-L-rhamnopyranosyl)-(1-6)-beta-D-glucopyranoside, 3,6-dihydroxy-2,4-dimethoxy-dibenzofuran 6-O-beta-D-glucopyranoside, 2,4-dimethoxy-3,6,9-trihydroxy-dibenzofuran 6-O-beta-D-glucopyranoside, 3,9-dihydroxy-2,4-dimethoxy-dibenzofuran 3-O-beta-D-glucopyranoside, and 2-methoxy-3,4,9-trihydroxy-dibenzofuran 4-O-beta-D-glucopyranoside based on spectroscopic analysis. Fortuneanosides G-J showed more potent tyrosinase-inhibitory activity than arbutin.     

Disposable multichannel immunosensors for 2,4-dichlorophenoxyacetic acid using acetylcholinesterase as an enzyme label

An improved version of the disposable multichannel immunochemical biosensor for the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) based on a screen-printed amperometric transducer and monoclonal antibodies (MAb) against 2,4-D is reported. Entrapment within a thin Nafion film was used for the direct immobilization of MAb at the electrode surface. The amount of the tracer (2,4-D conjugated to acetylcholinesterase) bound in a competitive immunochemical reaction was determined amperometrically using acetylthiocholine iodide as substrate. The measuring procedure (times of incubation with tracer and substrate, pH, tracer concentration) was optimized. The sensor was able to detect less than 0.01 μg/L of free 2,4-D in water. One analysis (8 samples) was completed in 30 min (20 min for immunochemical reaction, 5 min incubation with substrate, 5 min measurement). The performance of the immunosensor (two configurations) was evaluated on real samples (tap water) with added 2,4-D. The determined amounts (mean values 0.097 to 0.105 and 0.89 to 1.13) corresponded well with the added contents of 2,4-D (0.100 and 1.00 μg/L, respectively).     

Electrochemically Deposited Polymer‐Coated Gold Electrodes Selective for 2,4‐Dichlorophenoxyacetic Acid

Electropolymerized membranes on gold electrodes doped with 2,4‐dichlorophenoxyacetic acid (2,4‐D) were prepared from a solution containing resorcinol, o‐phenylenediamine and 2,4‐D. Fourier Transform Infrared (FTIR) spectroscopy was used to evaluate the incorporation and interaction of 2,4‐D with the polymer matrix prior to and after the sensing experiments. The FTIR data indicate that 2,4‐D does not leach appreciably from the polymer matrix under experimental conditions employed for the sensing studies. The electrochemical current response for 2,4‐D is compared for the doped polymer‐coated and control polymer‐coated electrode. The response of the doped polymer‐electrode was dependent on increasing concentrations of 2,4‐D and 2,4‐dichlorophenol while unresponsive to benzoic acid.     

Pteridines. Part XLII. Synthesis and properties of 8-substituted 2,4-dithiolumazines

Condensation reactions of the 5-amino-6-(subst. amino)-2,4-dithiouracils 12 and 13 with diacetyl or benzil led to the 6,7,8-trisubstituted 2,4-dithiolumazines 14 – 16 . Methylation of these compounds affected both thio functions forming various types of 2,4-bis(methylthio)lumazine derivatives depending on the nature of the substituents at C(7) and N(8). The 6,7,8-trimethyl-2,4-dithiolumazine ( 14 ) was converted into 7,8-dihydro-6,8-dimethyl–7-methylidene-2,4-bis(methylthio)pteridine ( 17 ), whereas the 8-methyl-6,7-diphenyl-(15) and the 8-(2-hydroxyethyl)-6,7-diphenyl-2,4-dithiolumazine ( 16 ) yielded the corresponding covalent inter- or intramolecular 7,8-adducts 18 – 21 . The unusual structures were proven by spectroscopic means and those of the alcohol adducts 20 and 21 , furthermore, confirmed by X-ray analysis.