Aromatic Acid Derivatives Research Articles

Chromatography in Silico, Quantitative Analysis of Retention of Aromatic Acid Derivatives

A quantitative analysis of the retention of aromatic acid derivatives in reversed-phase liquid chromatography (RPLC) is conducted using a molecular mechanics calculation in the CAChe program. The molecular interaction energy value is calculated by subtracting the energy value of the complex from the sum of energy values of a model phase and an analyte. Several model phases are constructed, and the feasibility of applying the method to a variety of compounds is examined based on improving the contact surface area and the capability of computer software and hardware. Interaction energy values are calculated for both molecular and ionic forms. The predicted retention factors of partially ionized acids obtained using a combination of dissociation constants correlated well with the values measured by RPLC with pH-controlled eluents.

Tetramethylated Dimeric Procyanidins Are Detected in Rat Plasma and Liver Early after Oral Administration of Synthetic Oligomeric Procyanidins

Procyanidins (PC) are of great interest in nutrition because they account for a major fraction of the total flavonoids ingested in Western diets and have health benefits in humans. However, it remains unknown which species of PC, namely, monomers, oligomers, or aromatic acid derivatives of gut microflora, are responsible for their beneficial effects in vivo. The high molecular complexity of PC extracts and PC-rich foods is a major problem in absorption studies. To circumvent this difficulty, we have synthesized oligomeric PC consisting of (-)-epicatechin units linked by ethyl bridges. The synthetic PC (SPC) only contains dimers, trimers, tetramers, and nanomers. After oral gavage of this SPC (200 mg/kg body weight) to male Wistar rats, tetramethylated dimeric PC (TDPC) were detected in plasma and liver. TDPC were detected in plasma as soon as 1 h after intake, reaching maximum concentrations (14 mg/L) 2 h after gavage. At this time, liver contained as much as 15 mug of TDPC per gram of tissue. In conclusion, orally administered dimeric PC are rapidly absorbed and internally methylated in rats. To our knowledge, this is the first time that methylated dimeric PC have been detected in plasma and liver. We consider that plasma and liver concentrations of TDPC are sufficient to exert a hormone-like effect and, therefore, that PC dimers are good candidates as agents of the biological activities of PC extracts and PC-rich foods.

Luminescent Properties of Zeolite Modified by Eu(III) and Tb(III) Complexes

The luminescence of the sorbates of the Eu(III) and Tb(III) complexes on the CaA-type zeolite with derivatives of aliphatic and aromatic carbonic acids has been studied. It is shown that the luminescent materials obtained can be used as light regulators and transformers which absorb energy in the UV spectral region and transform it into visible radiation.

Asymmetric Friedel-CraftsReactions: Catalytic Enantioselective Addition of Aromatic and HeteroaromaticC-H Bonds to Activated Alkenes, Carbonyl Compounds, andImines

The development and scope of catalytic enantioselective addition of aromatic and heteroaromatic C-H bonds to α,β-unsaturated alkenes, carbonyl compounds, and imines are presented. α,β-Unsaturated alkenes, 4-substituted 2-oxo-3-butenoate esters and alkylidene malonates react with indoles, furans and electron-rich aromatic compounds in the presence of chiral bisoxazoline-copper(II) complexes to give the Friedel-Crafts alkylation adduct in moderate to high yields and with up to >99.5% ee. Chiral bisoxazoline-copper(II) complexes can also catalyze the enantioselective addition of especially electron-rich aromatic compounds to activated carbonyl compounds such as glyoxylates and trifluoropyruvate to give e.g. optically active aromatic mandelic acid esters in good yields and enantioselectivities. Electron-rich aromatic compounds and heteroaromatic compounds react in an enantioselective fashion with activated N-protected α-imino esters to give optically active aromatic and heteroaromatic α-amino acid derivatives using chiral BINAP­-copper(I) complexes as the catalyst.

Fungal biosolubilization of rhenish brown coal monitored by Curie-point pyrolysis/gas chromatography/mass spectrometry using tetraethylammonium hydroxide

Residues and coal fractions that remained after the biosolubilization of Rhenish brown coal by strains of Lentinula edodes and Trametes versicolor have been studied by Curie-point pyrolysis/gas chromatography/mass spectrometry using tetraethylammonium hydroxide (NEt4OH) at 610 degrees C. To differentiate methyl derivatives of esters and ethers from free or bound hydroxyl and carboxyl groups NEt4OH was used in the thermochemolysis experiments instead the commonly used tetramethylammonium hydroxide. A comparison of humic acid fractions before and after fungal attack shows considerable alteration of the soluble macromolecules of coal. Depending on the coal fraction studied and the fungi used, the assortment of fatty acid esters released during the pyrolysis varies significantly. Furthermore, dicarbonic acid ethyl diesters as well as ethyl derivatives of aromatic ethers and acids yield information about humic acid structure and the biosolubilization of brown coal. Variations in the mixture produced are possibly caused by differences in the pattern of extracellular enzymes secreted that attack the macromolecular structural elements of brown coal. Therefore pyrolysis of native and microbiologically altered geomacromolecules using NEt4OH allows one to differentiate between free hydroxyl groups as well as substances that are attached to humic substances via ester or ether bridges, and their methylated counterparts.

Dissociation constants of neutral and charged acids in methyl alcohol. The acid strength resolution

A comprehensive and critical compendium of the p K a values in methanol of phenol derivatives, carboxylic acids, both aliphatic and aromatic acid derivatives, protonated amines and nitrogen-protonated heterocyclic bases is given in this paper. Values have been correlated with those obtained in aqueous solution and linear relationships for each series of compounds have been established. The proposed equations can be used to estimate accurately the dissociation constant value in water or in methanol of any compound of the mentioned chemical families, from the experimental value in methanol or in water, respectively. The acid strength resolution in the alcohol with reference to water is discussed according to the chemical structure of the compounds involved and to the solvating properties of methanol and water.

Synthesis and antiinflammatory activity of new derivatives of aromatic α-keto acids

Synthesis and antiinflammatory activity of new derivatives of aromatic α-keto acids

Use of sensitized luminescence of lanthanides in analysis of drugs

The sensitization of the Tb(III) and Eu(III) ions luminescence by drugs, the pyrocatechol, naphthyridine and heterocyclic aromatic acid derivatives, were studied. It was shown that a result of intramolecular energy transfer from the ligand molecule to the lanthanide ion increases the luminescence intensity of the latter by 108–1010 times. The luminescence properties of the complexes in solutions were investigated. The highly sensitive methods for luminescence determination of dopegyt, levodopum, dophaminum, nevigramon, furosemidum and cinchophenum were developed. The detection limits of the drugs are 0.0005, 0.02, 0.5, 0.01, 0.05 and 0.1, respectively.

Design and synthesis of a targeted set of aromatic amino acid derivatives for identification of new lead compounds

A targeted set of 256 aromatic α-amino acid derivatives is described to provide new lead compounds for biological screening. The utility is exemplified by identification of ligands for the human neuromedin B (hNMB) receptor, such as compound 3 (Ki hNMB 37nM). A targeted set of 256 aromatic α-amino acid derivatives is described to provide new lead compounds for biological screening. The utility is exemplified by identification of ligands for the human neuromedin-B receptor, such as compound 3 (K i hNMB 37nM).

Identification of phenolic acids and inositols in balms and tissues from an Egyptian mummy

A number of samples taken from an Egyptian mummy (ca. 100 B.C.) from the Guimet Museum in Lyon have been analyzed by GC-MS. Derivatives of aromatic acids (hydroxyhydrocinnamic, vanillic, protocatechuic and gallic acids) and inositols (non-methylated and mono- O-methyl) have been found among the constituents of extracts prepared by methanolysis and trimethylsilylation. From the reported electron impact mass spectra, ion sets where proposed for a sensitive and selective profiling of these selected compounds by mass fragmentometry. The source of gallic acid and inositol was found to be a vegetable tannin, an ingredient which was not previously known to be used for mummification in ancient Egypt. The nature and abundance ratios of the detected inositols also appeared to be a promising criterion further investigate the botanical source of the tannin employed.

ChemInform Abstract: A New, Palladium‐Catalyzed Synthesis of Aromatic Mercapturic Acid Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

A new, palladium-catalyzed synthesis of aromatic mercapturic acid derivatives

N-Acetyl-L-cysteine methyl ester ( 1) reacts under mild conditions with aryl iodides 2 in the presence of a palladium catalyst prepared in situ from Pd 2dba 3 and dppf to give S-aryl derivatives 3 in moderate to good yields.

Antinociceptive (aminoalkyl)indoles

The (aminoalkyl)indole (AAI) derivative pravadoline (1a) inhibited prostaglandin (PG) synthesis in mouse brain microsomes in vitro and ex vivo and exhibited antinociceptive activity in several rodent assays. In vitro structure-activity relationship studies of this new class of PG synthesis inhibitors revealed a correspondence in three respects to those reported for the arylacetic acids: (1) "alpha-methylation" caused an increase in PG inhibitory potency, (2) the (R)-alpha-methyl isomer was more active than the S isomer, (3) the hypothesized aroyl group conformation of the 2-methyl derivatives corresponded to the proposed and reported "active" conformations of the aroyl and related aromatic acetic acid derivatives. The 1H NMR chemical shift of the C-4 hydrogen of pravadoline in comparison to the deshielding seen with 50, which lacks a substituent at C-2, suggested that the carbonyl group of pravadoline is located near C-2 but is located near C-4 in 50. Associated with this conformational change of the carbonyl group of 1a is a diminution of PG synthetase inhibitory activity. The results of UV and difference nuclear Overhauser studies of the two compounds were consistent with these conformational assignments. The low eudismic ratios of the alpha-methyl derivatives and the observation that the side chain may be extended by three methylene groups without significant loss of PG inhibitory potency suggests that this class of inhibitors bound less strongly and less selectively to the active site of PG synthetase than do the arylacetic acids. Two AAIs, 1a and 30, were found to be metabolized to the corresponding acetic acid derivatives, both of which inhibited PG synthesis. An exception to the observation that the antinociceptive activity of the AAIs was associated with PG synthetase inhibitory activity was the 1-naphthoyl derivative 67 since neither it nor its acetic acid metabolite 74 inhibited PG synthesis. Yet 67 was antinociceptive in four different rodent assays. This naphthoyl derivative, like opioids, also inhibited electrically stimulated contractions in the mouse vas deferens (MVD) preparation. Unlike opioids, however, the inhibition was not antagonized by naloxone. A subseries of AAIs was identified, of which 67 was prototypic. These compounds lacked PG synthetase inhibitory activity, but their inhibitory potency in MVD preparations correlated roughly with their antinociceptive potency in vivo. Pravadoline was also inhibitory in the MVD. Its antinociceptive activity, therefore, may be a consequence of both its PG synthetase inhibitory potency and another antinociceptive mechanism, the latter associated with its inhibitory potency in the MVD.(ABSTRACT TRUNCATED AT 400 WORDS)

Aromatic acid derivatives as corrosion inhibitors for aluminium in acidic and alkaline solutions

The inhibition of aluminium corrosion in solutions of hydrochloric acid or sodium hydroxide has been studied using weight‐loss and hydrogen evolution methods. Benzoic acid and its derivatives inhibit acidic and alkaline corrosion effectively. The efficiency of inhibitors increases in the order: benzamide < benzaldehyde < acetophenone < benzoic acid < benzophenone (100%). The inhibition efficiency of acid anhydrides follows the sequence: pyromellitic > naphthalic > trimellitic. Inhibition takes place through adsorption by a one‐step process with greater efficiency in alkaline than in acidic methanolic solutions.

ChemInform Abstract: Reactions of Trimethylsilylmethyl Azide with Aromatic Acid Derivatives Catalyzed by Fluoride Ion.

AbstractThe reaction 0f(I) with (II) in the presence of KF and crown ether gives the products (IV) [by trimerization of the intermediate (III)] and (V)‐(VII) [yield of (VId) with 3mol KF: 22%].

Reactions of Trimethylsilylmethyl Azide with Aromatic Acid Derivatives Catalyzed by Fluoride Ion

Abstract The treatment of an aromatic acid halide with trimethylsilylmethyl azide (TMSMA) in the presence of potassium fluoride and crown ether gave triazine, methanediamine, and benzamide derivatives, while the reaction of acid anhydride with TMSMA gave tertiary amine together with methanediamine and benzamide under similar conditions.

ChemInform Abstract: PALLADIUM‐CATALYZED SYNTHESIS OF AROMATIC ACID DERIVATIVES BY CARBONYLATION OF ARYL IODIDES AND ALK3SNNU (NU = MEO, ET2N, PHS, ETS)

Chemischer InformationsdienstVolume 16, Issue 39 Preparative Organic Chemistry ChemInform Abstract: PALLADIUM-CATALYZED SYNTHESIS OF AROMATIC ACID DERIVATIVES BY CARBONYLATION OF ARYL IODIDES AND ALK3SNNU (NU = MEO, ET2N, PHS, ETS) N. A. BUMAGIN, N. A. BUMAGINSearch for more papers by this authorYU. V. GULEVICH, YU. V. GULEVICHSearch for more papers by this authorI. P. BELETSKAYA, I. P. BELETSKAYASearch for more papers by this author N. A. BUMAGIN, N. A. BUMAGINSearch for more papers by this authorYU. V. GULEVICH, YU. V. GULEVICHSearch for more papers by this authorI. P. BELETSKAYA, I. P. BELETSKAYASearch for more papers by this author First published: October 1, 1985 https://doi.org/10.1002/chin.198539141Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue39October 1, 1985 RelatedInformation

Hetero‐chain polymers based on natural amino acids. Synthesis of polyamides from Nα, Nε‐bis(trimethylsilyl)lysine alkyl esters

AbstractHigh‐molecular‐weight polyamides based on the natural amino acid lysine were synthesized by condensation of Nα, Nε‐bis(trimethylsilyl)lysine alkyl esters (1a–c) with derivatives of aromatic dicarboxylic acids (2a–c). The best results were obtained with diacyl dichlorides. However, in the case of aliphatic dicarboxylic acid derivatives, preference should be given to their active diesters. The properties of the resulting polyamides were shown to be determined, to a considerable degree, by the nature of the reaction medium. Polyamides with free carboxyl groups, capable of further polymeranalogous conversions, were obtained by means of saponification of the side chain alkyl ester groups. The substituted phenols, resulting from the polycondensation of 1a–c with active diesters, could be used for the synthesis of polyamides with active ester groups in the side chains.

Palladium-catalyzed synthesis of aromatic acid derivatives by carbonylation of aryl iodides and Alk 3SnNu (Nu = MeO, Et 2N, PhS, EtS)

Carbonylation of the ArI/Alk 3SnNu system (Nu=MeO, Et 2N), leading to esters and amides of substituted benzoic acids, occurs readily in the presence of phosphinepalladium complexes. When Nu = PhS and EtS either a cross-coupling product (Ar = p-NO 2C 6H 4) or a carbonylation product (Ar = Ph) is formed predominantly, depending on the nature of ArI. Stoichiometric reactions of ArPdI(PPh 3) 2 with carbon monoxide, resulting in acylpalladium complexes, and reactions of ArCOPdI(PPh 3) 2 with Alk 3SnNu have been studied. Some mechanistic aspects are discussed.

Identification of aromatic dihydroxy acids in biological fluids.

3,5-Dihydroxyphenylpropionic acid, 3,5-dihydroxycinnamic acid and 2,3-dihydroxycinnamic acid were detected for the first time to be components of human urine. In the course of this investigation all constitutional isomers of dihydroxy-benzoic, -phenylpropionic, -phenylacetic and -cinnamic acid were synthesized. Mass spectra and retention indices of methyl and trimethylsilyl (TMS) derivatives were determined. In contrast to many other substituted aromatic compounds the mass spectra of methyl and TMS derivatives of dihydroxy aromatic acids often allow a firm distinction to be made between constitutional isomers: TMS derivatives of aromatic acids containing two hydroxy groups located in the ortho position to each other can be recognized by ions resulting from a primary cleavage reaction mainly in the side chain or ester group, followed by loss of tetramethylsilane. In methyl derivatives of 1,2,3-trisubstituted isomers, methoxy groups are lost much more easily from the ions corresponding to the benzylic cleavage than in other isomers. Methyl derivatives of dihydroxycinnamic acids containing at least one methoxy group in the ortho position to the side chain are characterized by a fragmentation reaction, corresponding to the loss of dimethyl ether. TMS and methyl derivatives of 3,5-dihydroxy aromatic acids show unique structure-specific fragmentation reactions.