Plain Thin-layer Chromatography of Some Herbicides and Related Compounds on Admixture of Barium Sulfate and Calcium Sulphate in Mixed Solvents

Abstract

Some carboxylic herbicides and plant growth regulators such as benzoic acid, 4-chlorophenoxyacetic acid, cinnamic acid, 2,4-D, indole-3-acetic acid, indolepropionic acid, α-naphthalleneacetic acid, β-naphthal eneacetic acid, β-naphthoxyacetic acid, phenoxyacetic acid, TCA and 2,4,5-T have been separated on BaSO₄-CaSO₄ (1:1) coatings in mixed solvent systems.

Quantitative separations of indole-3-acetic acid (100 μg) from 50–100 μg of benzoic acid, α-naphthaleneacetic acid and 2,4,5-T have been carried out successfully.     

Synthesis of natural pulvinic acids based on a ‘[3+2] cyclization-Suzuki cross-coupling’ strategy

A number of pulvinic acid natural products were prepared based on Suzuki cross coupling reactions of α-hydroxy-γ-alkylidenebutenolides which are readily available by cyclization of 1,3-bis-silyl enol ethers with oxalyl chloride. The formal total synthesis of pulvinic acid, atromentic acid, gomphidic acid and of 4-hydroxypulvinic acid, 4′-hydroxypulvinic acid and iso-gomphidic acid are reported. In addition, total syntheses of pinastric acid, xerocomic acid and variegatic acid were accomplished.     

DILUTE SOLUTION BEHAVIOR OF CHITOSAN IN DIFFERENT ACID SOLVENTS

Dilute solution behavior of chitosan was studied in formic acid, acetic acid, lactic acid andhydrochloric acid aqueous solution under different pH values. The reduced viscosities, η_(sp)/C,ofchitosan solutions were dependent on the properties of acid and pH value of solvents. For a givenchitosan concentration, η~(sp)/C decreased with the increase of acid concentration, or decreasing pHof solvent, indicating shielding effect of excessive acid similar to adding salt into solution. Thestabilities of dilute chitosan solution in formic acid and lactic acid were better than that in acetic acid and hvdrochloric acid.     

Synthesis and Hepatic Metabolism of Xanthobilirubinic Acid Regioisomers

Summary.  A set of four regioisomeric dipyrrinone propionic acids has been synthesized and their hepatic metabolism examined in rats: xanthobilirubinic acid and pseudo-xanthobilirubinic acid each with a propionic acid on a pyrrole ring; exo-ψ-xanthobilirubinic acid and endo-ψ-xanthobilirubinic acid, each with a propionic acid transposed to a lactam ring. After intravenous injection all four isomers were excreted to some degree in unchanged form in bile in normal rats. Xanthobilirubinic acid, the structurally closest dipyrrinone to bilirubin, and exo-ψ-xanthobilirubinic acid were excreted almost entirely in unchanged form. However, a small fraction of xanthobilirubinic acid acyl glucuronide was also detected. More extensive acyl glucuronidation was observed for pseudo-xanthobilirubinic acid, and endo-ψ-xanthobilirubinic acid underwent slow metabolism to unidentified more polar products that did not seem to be glucuronides.     

Chromanone Derivatives from the Pericarps of Calophyllum polyanthum

Three new chromanone derivatives, calopolyanic acid ( 1 ), isocalopolyanic acid ( 2 ), and isorecedensic acid ( 3 ), were isolated from the pericarps of Calophyllum polyanthum Wall . ex Choisy , along with seven known compounds, apetalic acid, blancoic acid, chapelieric acid, methyl isoapetalate, isoapetalic acid, isocalolongic acid, and recedensic acid. All of these compounds were reported from C. polyanthum for the first time. The structures of 1 – 3 were elucidated by spectroscopic methods.     

Degradation of benzoic acid and its derivatives in subcritical water

In this research, the stability of benzoic acid and three of its derivatives (anthranilic acid, salicylic acid, and syringic acid) under subcritical water conditions was investigated. The stability studies were carried out at temperatures ranging from 50 to 350 °C with heating times of 10–630 min. The degradation of the benzoic acid derivatives increased with rising temperature and the acids became less stable with longer heating time. The three benzoic acid derivatives showed very mild degradation at 150 °C. Severe degradation of benzoic acid derivatives was observed at 200 °C while their complete degradation occurred at 250 °C. However, benzoic acid remained stable at temperatures up to 300 °C. The degradation products of benzoic acid and the three derivatives were identified and quantified by HPLC and confirmed by GC/MS. Anthranilic acid, salicylic acid, syringic acid, and benzoic acid in high-temperature water underwent decarboxylation to form aniline, phenol, syringol, and benzene, respectively.     

THE 7F0→5D0 EXCITATION SPECTRA OF EUROPIUM(III) COMPLEXES OF AMINOCARBOXYLIC ACIDS

Abstract

The complexation of ethylenediamine, triethylenetetramine, acetic acid, glutaric acid, succinic acid, maleic acid, fumaric acid, malonic acid, iminodiacetic acid, nitrilotriacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, N ¹-(4-isothiocyanatobenzyl)di-ethylene-triaminetetraacetic acid, trans-1, 2-diaminocyclohexane-N, N, N, N'-tetraacetic acid and diethylenetriaminepentaacetic acid (DTPA) with Eu³⁺ ion in aqueous solution has been studied by using the ⁷F_O→⁵D_O excitation spectroscopy of the Eu³⁺ ion. Because the energy of the ⁷F_O→⁵D_O transition of Eu³⁺ is dependent on the coordinating oxygen atoms, the “nephelauxetic” shift parameters for most typical coordinating atoms, such as in the carboxylate group, aliphatic amino nitrogen and the pyridine nitrogen atom were recalculated by multilinear regression with the present set of 22 complexes. The calculated shift parameters were used for the analysis of the excitation spectra of the complexes of diethylenetriaminepentaacetic acid, trans-1, 2-diaminocyclo-hexane-N, N, N, N', -tetraacetic acid and N-(2-hydroxyethyl)ethylenediaminetriacetic acid.     

Determination of Monochloroacetic Acid and Dichloroacetic Acid for Quality Control of Acetic Acid Chlorination Industry by Ion Chromatography

An ion chromatographic method is described for the purpose of quality control in the process of monochloroacetic acid production. Using 2.5 mM NaOH–10% methanol as eluent, the simultaneous determination of acetic acid, monochloroacetic acid, dichloroacetic acid, and Cl⁻ was obtained in a single run. Monochloroacetic acid and dichloroacetic acid showed good linearity in the range 0.1–20 and 0.15–20 μg/ml and correlation coefficients were 0.9999 and 0.9998, respectively. The detection limits (signal-to-noise ratio 3:1) of monochloroacetic acid and dichloroacetic acid were 17 and 25 ng/ml. This simple, sensitive, and time-saving method can be applied for composition analysis in acetic acid chlorination production.     

Fatty acid variability in three medicinal herbs of Panax species

Background

Fatty acid profiling has been widely used in the bacteria species identification, we hypothesized that fatty acid characteristics might discriminate the Panax herbs according to species. To test the hypothesis, fatty acids of Panax species, including Panax ginseng, Panax notoginseng and Panax quinquefolius, were characterized and compared using gas chromatography–mass spectrometry (GC-MS) followed by multivariate statistical analysis.

Results

The content of investigated 11 fatty acids, including myristic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, heptadecanoic acid, stearic acid, oleic acid, linoleic acid, α-linolenic acid, arachidic acid and eicosadienoic acid, obviously varied among three species, suggesting each species has its own fatty acid pattern. Principal component analysis and hierarchical clustering analysis according to the absolute and relative contents of fatty acids, showed that 30 tested samples could be clearly differentiated according to the species.

Conclusions

These findings demonstrated that GC-MS-based fatty acid profiling coupled with multivariate statistical analysis provides reliable platform to classify these three Panax species, which is helpful for ensuring their safety and efficacy.     

Effects of fatty acids on growth and poly-3-hydroxybutyrate production in bacteria

The effects of saturated and unsaturated fatty acids (lauric acid, palmitic acid, steric acid, oleic acid, linoleic acid, soybean oil) on Sphaerotilus natans, 0B17 (Pseudomonas sp.), and recombinant Escherichia coli DH5(/pUC19/CAB were studied. Oleic acid enhances Poly-3-hydroxybutyrate (PHB) production in these three bacterial strains, suggesting that the single double bond of the acid activates the polyhydroxylkanoate accumulation enzymatic reaction. Under the effect of lauric acid and linoleic acid, the growth of S. natans and 0B17 were totally inhibited. However, the enhanced PHB accumulation in recombinant E. coli was observed.     

Optimising oxygen-sensitivity of optical sensor using pyrene carboxylic acid by myristic acid co-chemisorption onto anodic oxidized aluminium plate

Optical oxygen-sensitivity using pyrene carboxylic acid with long alkyl chain (1-pyrenedecanoic acid and 1-pyrenedodecanoic acid) and myristic acid co-chemisorption layer was controlled by varying the molar ratio of myristic acid to pyrene carboxylic acid. The ratio I₀/I₁₀₀, where I₀ and I₁₀₀ represent the detected fluorescence intensities from a substrate exposed to 100% argon and 100% oxygen, respectively, is used as an indicator of the sensitivity of the sensing film. At a composition ratio of 1 pyrene carboxylic acid to 10 myristic acids, the I₀/I₁₀₀ attained its maximum value and then the ratio decreased with increase in the molar ratio of myristic acid to pyrene carboxylic acid. The Stern-Volmer constant (K_SV) also attained its maximum value at a composition ratio of one pyrene carboxylic acid to ten myristic acids and then the ratio decreased with increase in the molar ratio of myristic acid to pyrene carboxylic acid. The oxygen-sensitivity of optical sensor using pyrene carboxylic acid is optimized by myristic acid co-chemisorption.     

Zur Bildung isomerer Trihydroxy-octadecensäuren bei der enzymatischen Oxydation von Linolsäure durch Gerstenmehl

Incubation of linoleic acid with barley flour at pH 6.8 leads to the formation of three isomeric trihydroxy octadecenoic acids, namely: 9,12,13-trihydroxy-10-trans-octadecenoic acid, 9,10,13-trihydroxy-11-trans-octadecenoic acid and 9,10,11-trihydroxy-12-trans-octadecenoic acid. The acids were isolated by column chromatography using silicic acid and boric acid impregnated silicic acid and their structures were ascertained by means of IR, NMR and mass spectroscopy.

---

---

Mit 4 Abbildungen     

Nachweis isomerer Aminobenzolsulfonsäuren nebeneinander

Zusammenfassung Beimengungen isomerer Aminobenzolsulfonsäuren können mit Hilfe folgender Farbreaktionen nachgewiesen werden: 1. Orthanilsäure in Metanilsäure bzw. Sulfanilsäure mit diazotierter Metanilsäure; 2. Metanilsäure bzw. Sulfanilsäure in Orthanilsäure mit diazotiertem Anilin; 3. Metanilsäure bzw. Orthanilsäure in Sulfanilsäure mit Dimethylformamid; 4. Metanilsäure in Sulfanilsäure mit Salzsäure-Kaliumbromat und 5. Orthanilsäure bzw. Sulfanilsäure in Metanilsäure mit Brom.

---

Summary Admixtures of isomeric aminobenzenesulfonic acids can be detected by means of the following color reactions: 1. orthanilic acid in metanilic acid or sulfanilic acid with diazotized inetanilic acid; 2. metanilic acid or sulfanilic acid in orthanilic acid with diazotized aniline; 3. metanilic acid or orthanilic acid in sulfanilic acid with dimethylformamide; 4. metanilic acid in sulfanilic acid with hydrochloric acid-potassium bromate and 5. orthanilic acid or sulfanilic acid in metanilic acid with bromine.

     

13N-NMR spectroscopy. XXXV. Sequence analysis of alternating and random copolyamides made up of aliphatic and aromatic ω-amino acids

Alternating copolyamides of various ω-amino acids were synthesized by base-catalyzed polycondensation of N-isothiocyanatoacyl ω-amino acids in solution. Derivatives of the following amino acids were used: glycine, β-alanine, γ-aminobutyric acid, δ-aminovaleric acid, ε-aminocaproic acid, D ,L -β-aminobutyric acid, trans-4-aminocyclohexane 1-carboxylic acid, 4-aminophenyl acetic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 3-amino-4-methyl benzoic acid, and 4-amino-3-methyl benzoic acid. The base-catalyzed polycondensation at lower temperatures gave purer products than the bulk condensation at 180–200°C. ¹³C-NMR and natural-abundance ¹⁵N-NMR spectra measured in trifluoroacetic acid demonstrate that in most cases undisturbed alternating sequences were obtained. Strong neighboring residue effects and long-range sequence effects were found in the ¹⁵N-NMR spectra, and structure/shift relationships are discussed. The sequences of copolyamides obtained by copolymerizations of lactams or β-amino acid N-carboxyanhydrides were investigated by both ¹⁵N-NMR and ¹³C-NMR spectroscopy. ¹³C-NMR spectroscopy was found to be more useful if the copolyamides consist of ω-amino acid units of different chain length. However, ¹⁵N-NMR spectroscopy is more suited if the monomer units differ exclusively by their substituents.     

含胆酸高分子化合物的制备和特性*

胆酸是哺乳动物体内合成的一种天然化合物,具有特殊的分子结构和优良的生物适应性。由胆酸合成的高分子化合物保持了胆酸的部分性质,如双亲性、手性、侧基反应活性和自组装性能等。在化学和药学领域,含胆酸高分子材料具有重要的应用价值。本文从自由基聚合形成的含胆酸高分子化合物、胆酸修饰的高分子化合物和胆酸聚合物等几个方面综述了含胆酸高分子化合物的制备和特性,并对胆酸在高分子材料方面的新用途作了展望。     

Preparation of chitosan‐based molecularly imprinted material for enantioseparation of racemic mandelic acid in aqueous medium by solid phase extraction

An S‐mandelic acid imprinted chitosan resin was synthesized by cross‐linking chitosan with glutaraldehyde in 2% acetic acid solution. S‐Mandelic acid imprinted chitosan resin was used to enantioselectively separate racemic mandelic acid in aqueous medium. When keeping the pH of sample solution (100 mM Tris‐H₃PO₄) at 3.5 and adsorption time at 40 min, the enantiomer excess of mandelic acid in supernatant was 78.8%. The adsorption capacities of S‐mandelic acid imprinted chitosan resin for S‐ and R‐mandelic acid were determined to be 29.5 and 2.03 mg/g, respectively. While the adsorption capacities of non‐imprinted cross‐linked chitosan for S‐ and R‐mandelic acid were 2.10 and 2.08 mg/g, respectively. The result suggests that the imprinted caves in S‐mandelic acid imprinted chitosan resin are highly matched with S‐mandelic acid molecule in space structure and spatial arrangement of action sites. Interestingly, the enantiomer excess value of mandelic acid in supernatant after adsorption of racemic mandelic acid by R‐mandelic acid imprinted cross‐linked chitosan was 25.4%. The higher enantiomer excess value by S‐mandelic acid imprinted chitosan resin suggests that the chiral carbons in chitosan and the imprinted caves in S‐mandelic acid imprinted chitosan resin combine to play roles for the enantioselectivity of S‐mandelic acid imprinted chitosan resin toward S‐mandelic acid. Furthermore, the excellent enantioselectivity of S‐mandelic acid imprinted chitosan resin toward S‐mandelic acid demonstrates that using chiral chitosan as functional monomer to prepare molecularly imprinted polymers has great potential in enantioseparation of chiral pharmaceuticals.     

Studies on the Ion-Exchange Chromatographic Separation of L-Ascorbic Acid and Oxalic Acid

L-Ascorbic acid and oxalic acid could be successfully separated with a column of 8% cross-linked sulfonated polystyrene cation-exchange resin in hydrogen form, and eluted with 0.01% aqueous solution of nitric acid, sulfuric acid, or phosphoric acid. Among the mineral acids used, nitric acid showed the best separatory effect. The minimum detectable quantities of the acids were 0.05 μg and 0.5 μg per 0.5 ml sample solution for L-ascorbic acid and oxalic acid, respectively. Under this condition, the acids could be detected by using automatic UV-monitor apparatus.     

Polyaniline doped by a new class of dopants,benzoic acid and substituted benzoic acid: synthesis and characterization

This work reports on a new class of dopants, benzoic acid and substituted benzoic acids such as 2‐hydroxybenzoic acid, 2‐chlorobenzoic acid, 4‐nitrobenzoic acid, 2‐methoxybenzoic acid, 3‐methylbenzoic acid, 4‐methylbenzoic acid, 3‐aminobenzoic acid and 4‐aminobenzoic acid, for polyaniline. Benzoic acids can be used to dope polyaniline by mixing benzoic acid (or a substituted benzoic acid) with polyaniline in the common solvent 1‐methyl‐2‐pyrrolidone. Properties of benzoic acid doped polyaniline salts are studied using Fourier transform infra‐red, X‐ray diffraction spectroscopy, scanning electron microscopy, thermogravimetric analysis and conductivity measurements. The conductivity of polyaniline‐benzoic acid salt was found to be high (10⁻² S/cm) when compared to polyaniline‐substituted benzoic acid salts (10⁻³–10⁻⁵ S/cm). Copyright © 2005 John Wiley & Sons, Ltd.     

Preparation of 2‐, 4‐, 5‐, and 6‐aminonicotinic acid tert‐butyl esters

Procedures are reported to prepare the tert‐butyl esters of 2‐aminonicotinic acid, 4‐aminonicotinic acid, 5‐aminonicotinic acid, and 6‐aminonicotinic acid from 2‐chloronicotinic acid, 4‐chloronicotinic acid, 5‐bromonicotinic acid, and 6‐chloronicotinic acid, respectively, without need for purification of intermediates. J. Heterocyclic Chem., (2012).     

锰(Ⅲ)离子与羧酸或α-羟基羧酸体系引发丙烯酰胺聚合

 锰(Ⅲ)离子可以引发烯类单体自由基聚合。羧酸,α-羟基羧酸对丙烯酰胺聚合有促进作用,其活性顺序为羟基多元羧酸(柠檬酸)>羟基羧酸(乳酸)>羧酸(正丁酸)。测定了在较高酸性([H⁺]=3.0M)的硫酸水溶液中,单独Mn³⁺,Nn³⁺-乙醇酸,Mn³⁺-乳酸引发丙烯酰胺聚合的活化能与动力学方程。