Aromatic Acid Esters Research Articles

ChemInform Abstract: Interaction of 2-(2-Azahetaryl)-3-oxo-4-chlorobutane Nitriles with Esters of Aromatic Amino Acids.

The reaction of 2-(2-azahetaryl)-3-oxo-4-chlorobutane nitriles with esters of aromatic acids was studied. A series of 1H,4H-3-(2-azahetaryl)pyrrolo[1,2-a] quinazoline-2,5-diones and 1-aryl-2-amino-3-(2-azahetaryl)-4-(5H)-oxopyrroles was obtained. The reaction of the latter with hydrazine and acetic anhydride was investigated.

Lobeline esters as novel ligands for neuronal nicotinic acetylcholine receptors and neurotransmitter transporters

Vesicular monoamine transporter-2 (VMAT2) is a viable target for development of pharmacotherapies for psychostimulant abuse. Lobeline (1) is a potent antagonist at alpha4beta2 * nicotinic acetylcholine receptors, has moderate affinity (K(i)=5.46microM) for VMAT2, and is being investigated currently as a clinical candidate for treatment of psychostimulant abuse. A series of carboxylic acid and sulfonic acid ester analogs 2-20 of lobeline were synthesized and evaluated for interaction with alpha4beta2 * and alpha7 * neuronal nicotinic acetylcholine receptors (nAChRs), the dopamine transporter (DAT), serotonin transporter (SERT) and VMAT2. Both carboxylic acid and sulfonic acid esters had low affinity at alpha7 * nAChRs. Similar to lobeline (K(i)=4nM), sulfonic acid esters had high affinity at alpha4beta2 * (K(i)=5-17nM). Aromatic carboxylic acid ester analogs of lobeline (2-4) were 100-1000-fold less potent than lobeline at alpha4beta2 * nAChRs, whereas aliphatic carboxylic acid ester analogs were 10-100-fold less potent than lobeline at alpha4beta2 *. Two representative lobeline esters, the 10-O-benzoate (2) and the 10-O-benzenesulfonate (10) were evaluated in the (36)Rb(+) efflux assay using rat thalamic synaptosomes, and were shown to be antagonists with IC(50) values of 0.85microM and 1.60microM, respectively. Both carboxylic and sulfonic acid esters exhibited a range of potencies (equipotent to 13-45-fold greater potency compared to lobeline) for inhibiting DAT and SERT, respectively, and like lobeline, had moderate affinity (K(i)=1.98-10.8microM) for VMAT2. One of the more interesting analogs, p-methoxybenzoic acid ester 4, had low affinity at alpha4beta2 * nAChRs (K(i)=19.3microM) and was equipotent with lobeline, at VMAT2 (K(i)=2.98microM), exhibiting a 6.5-fold selectivity for VMAT2 over alpha4beta2 nAChRs. Thus, esterification of the lobeline molecule may be a useful structural modification for the development of lobeline analogs with improved selectivity at VMAT2.

Biomonitoring of Detoxifying Activity as Measured by CYP1A1 Induction in Yangtze and Jialing Rivers in Chongqing City in China

In order to determine the potential toxicities of organic pollutants in the river water of Chongqing City (China), chemicals were extracted from surface water of the Yangtze River and Jialing River between August 2004 and January 2005. Gas chromatography/mass spectrometry (GC/MS) analysis showed that the main compounds detected were polycyclic aromatic hydrocarbons (PAH) and phthalate acid esters (PAE). The ethoxyresorufin O-deethylase (EROD) test showed that the toxic equivalency (TEQ) values of the samples ranged from 0.9 to 13.3 × 10−4 pg 2,3,7,8-TCDD/L river water. Incubation of H4IIE cells with organic extracts produced a time-dependent induction of cytochrome P-450 1A1 (CYP1A1) mRNA expression as determined by (1) reverse-transcription polymerase chain reaction (RT-PCR), (2) positive binding to aryl hydrocarbon receptor (AhR), and (3) activation of xenobiotic response element (XRE) by electrophoretic mobility shift assay (EMSA). Data indicated that organic extracts from the river water of Chongqing City induced CYP1A1 activity in hepatocytes in vitro. A possible mechanism underlying toxicity might involve the AhR signal pathway, but further studies are necessary.

Design and synthesis of a photocleavable biotin-linker for the photoisolation of ligand–receptor complexes based on the photolysis of 8-quinolinyl sulfonates in aqueous solution

The ability of avidin (Avn) to form strong complex with biotin (Btn) is frequently used in the detection and isolation of biomolecules in biochemical, analytical, and medicinal research. The fact that the binding is nealy irreversible, however, constitutes a drawback in term of the isolation and purification of intact biomolecules. We recently found that 8-quinolinyl esters of aromatic or aliphatic sulfonic acids undergo photolysis when irradiated at 300–330 nm in aqueous solution at neutral pH. In this work, a biotin–dopamine (BD) conjugate containing a photocleavable 8-quinolinyl benzenesulfonate (QB) linker, BDQB, was designed and synthesized for use in the efficient recovery of dopamine–protein (e.g., antibody) complexes from an Avn–Btn system. The complexation of BDQB with a primary anti-dopamine antibody (anti-dopamine IgG 1 from mouse) on an Avn-coated plate was confirmed by an enzyme-linked immunosorbent assay (ELISA) utilizing a secondary antibody (anti-IgG 1 antibody) conjugated with horseradish peroxidase (HRP). Upon the photoirradiation (at 313 nm) of the BDQB–IgG 1 complex, the release of dopamine–IgG 1 complex was confirmed by ELISA. Characterization of the resulting photoreleased dopamine–anti-dopamine IgG 1 complex was performed by SDS–PAGE and Western blot.

Synthesis of (5R,8R)-2-(3,8-Dimethyl-2-oxo-1,2,4,5,6,7,8,8α-octahydroazulen-5-yl) Acrylic Acid (Rupestonic Acid) Amide Derivatives and in vitro Inhibitive Activities against Influenza A3,B and Herpes Simplex Type 1 and 2 Virus

19 Aromatic ring and L-amino acid ester contained rupestonic acid amide derivatives 2a~2l, 3a~3g were synthesized and preliminarily evaluated in vitro against influenza virus <TEX>$A_3$</TEX>,B and herpes simplex virus type 1 (HSV-1), 2(HSV-2) by the national center for drug screening of China. The rusults showed that 2i possessed the highest inhibition against both influenza virus <TEX>$A_3\;(TC_{50}\;=\;120.6\;{\mu}mol/L,\;IC_{50}=\;19.2\;{\mu}$</TEX>mol/L, SI = 6.3) and B (T<TEX>$C_{50}\;=\;120.6\;{\mu}mol/L,\;IC_{50}=\;29.9\;{\mu}$</TEX>mol/L, SI = 4.0); 2g was more active against influenza <TEX>$A_3$</TEX> virus at very low cytotoxicity (<TEX>$TC_{50}\;>\;2092.1\;{\mu}mol/L,\;IC_{50}=\;143.7\;{\mu}mol/L,$</TEX> SI > 14.6) than the parent compound; Compounds 2b, 2c, 2f showed higher activities both against HSV-1 and HSV-2 than that of the parent compound, and 2f was the most potent inhibitor of HSV-1 (<TEX>$TC_{50}\;=\;200.0\;{\mu}mol/L,\;IC_{50}\;=\;11.3\;{\mu}mol$</TEX>/L, SI = 17.7 ) and HSV-2 (<TEX>$TC_{50}\;=\;200.0\;{\mu}mol/L,\;IC_{50}\;=\;20.7\;{\mu}mol$</TEX>/L , SI = 9.7).

Simple and Efficient Synthesis of Racemic Substituted Mandelic Acid Esters from Nonactivated Arenes and Ethyl Glyoxylate

Direct synthesis of racemic aromatic α-hydroxyacetic acid esters via Friedel-Crafts reaction of nonactivated, simple arenes with ethyl glyoxylate promoted by SnCl 4 or AlCl 3 is described. The use of SnCl 4 opens a fast access to various alkyl- and aryl-substituted mandelic acids esters at room temperature within two hours in good yield (>80%) and with high regioselectivity. The procedure was successfully employed also for the alkylation of compounds with condensed aromatic rings. Alternative hydroxyalkylations with AlCl 3 require longer reaction time and higher temperature to get a good yield.

Effects of Aromatic Acids on Stimulating Blood Circulation and Removing Blood Stasis

Abstract Objective The aim of this study is to determine the effects of aromatic acids on stimulating blood circulation and removing blood stasis. Methods A systematic study of aromatic acids concentration in the herbs frequently used in Traditional Chinese Medicine (TCM) formula to stimulate blood circulation and remove blood stasis is performed to help to establish a bio-activity basis and a compatibility principle for TCM formula. Results Through the study, we find that aromatic acids' effect of stimulating blood circulation and removing blood stasis may be increased by combing with alkali. Besides, aromatic acid esters can better stimulate blood circulation and remove blood stasis. What's more, the solubilization of aromatic acids helps stimulating blood circulation and removing blood stasis. Conclusions Aromatic acids have been proved to be effective in preventing platelet aggregation and anti-thrombus. On the one hand, they have a biological contribution to TCM formula and on the other hand they improve blood circulation through working with other elements in the TCM formula. Aromatic acids make a lot of contributions to the whole TCM formula.

Manifestations of crystallinity in polyamidobenzimidazoles

Polyamidobenzimidazoles derived from 3,3′,4,4′-tetraaminodiphenyl ether, diphenyl esters of aliphatic and aromatic dicarboxylic acids, and ɛ-caprolactam were prepared by solid-phase polycondensation. The relative degree of crystallinity, imparting the plasticity to the polymers as compared to the corresponding polybenzimidazoles, was determined by X-ray phase analysis.

Cytotoxic kurubasch aldehyde from Trichilia emetica

Kurubasch aldehyde, a sesquiterpenoid with an hydroxylated humulene skeleton, was isolated as free alcohol from Trichilia emetica Vahl. (Meliaceae), belonging to the order Sapindales. Related substances have been previously found in plants as esters of aromatic acids, and these plants were species belonging to the distant order Apiales. This is the first report of humulenes found in the genus Trichilia and only the second of humulenes in the order Sapindales. The aldehyde is a modest inhibitor of the growth of Plasmodium falciparum (IC50 76 µM) and slow-proliferating breast cancer cells MCF7 (78 µM), but a potent inhibitor of proliferation of S180 cancer cells (IC50 7.4 µM).

Organosilicon synthesis of isocyanates: III. Synthesis of aliphatic, carbocyclic, aromatic, and alkylaromatic isocyanatocatboxylic acid esters

A series of aminoacid esters was prepared by treating the aminoacid suspensions in ethanol with thionyl chloride. Best conversion of aminoacid esters to corresponding isocyanates was achieved in the case of aromatic and carbocyclic aminoesters by phosgeneation of their N-silyl derivatives, and in the case of aliphatic and alkylaromatic aminoesters by phosgeneation of O-silyl or N,O-bissilylurethanes on their basis. In the last case additional step of esterification of the by-products isocyanatoalkylcarboxylic acid chlorides is required after phosgeneation. Unusual generation of cynnamates and intramolecular N→O-migration of trimethylsilyl group in the solutions of silylated alkylaromatic β-aminoacid esters were found.

Extracellular Polymer Produced in the Presence of Copper Minerals

A qualitative and semiquantitative assay was applied to estimate production of peripheral exopolymers by strains of bacteria isolated from flotation wastes during growth on copper sulphides and copper minerals wastes at neutral pH. Exopolymer production, expressed as percentage of Alcian Blue adsorption per μ g of cell protein, was the lowest on a complete organic medium and the highest on a nutrient-limited mineral medium. The exopolymer was highly resistant to acid hydrolysis and contained hydrocarbons, saturated and unsaturated fatty acids, aromatic acids and aromatic acid esters, which are well known as artificial surfactants and plasticizers. Carbohydrates appeared incidentally and in trace amount only. Chemical components of the exopolymer or chemically similar compounds also were found in black shale particles in the flotation wastes.

Microbial deracemisation of aromatic β-hydroxy acid esters

Aromatic β-hydroxy acid esters were found to undergo deracemisation using whole cells of Candida parapsilosis. The conditions for the deracemisation reaction were optimised where ∼75% isolated yield and >95% enantiomeric excess of the product was achieved. The effect of electron donating as well as electron withdrawing groups present in the standard substrate, ethyl 3-hydroxy 3-phenyl propionate was studied to establish the generality of the reaction. The enantiomeric excess of the product remains high (>95%) irrespective of the different substituents in the para position but substitution at the ortho position obstructs the process. Similarly, ethyl and methyl esters of the standard substrate undergo deracemisation reaction giving high ee of the product, but the benzyl ester of the standard substrate did not undergo deracemisation.

Biotransformation of isoprenoids and shikimic acid derivatives by a vegetable enzymatic system.

In biotransformations carried out under similar conditions enzymatic systems from carrot (Daucus carota L.), celeriac (Apium graveolens L. var. rapaceum) and horse-radish (Armoracia lapathifolia Gilib.) hydrolyzed the ester bonds of acetates of phenols or alicyclic alcohols. Nevertheless, methyl esters of aromatic acids did not undergo hydrolysis. Alcohols were oxidized to ketones in a reversible reaction.

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.

Aromatic β-Amino Acids as Asp-Phg Mimics in LDV Derived VLA-4 Antagonists­

Aromatic β-amino acid esters 2a-h were prepared in racemic and enantiomerically pure form by the Radionow reaction or based on the method described by Davis and used as mimics of the Asp-Phg C-terminus in LDV derived VLA-4 antagonists. As a promising β-amino acid ester, 11 was identified and used for the synthesis of the highly potent VLA-4 antagonist S9059 with an IC50 of 1.6 nM in a cell attachment assay.

Egyptian propolis: 3. Antioxidant, antimicrobial activities and chemical composition of propolis from reclaimed lands.

The free radical scavenging effect of two propolis samples collected from reclaimed land, Egypt as well as of vitamin C and caffeic acid in 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical system was determined. The antimicrobial (Staphylococcus aureus; Escherichia coli and Candida albicans) activity was also investigated. The results of the free radical scavenging effect of El-Saff and Ismailia propolis showed a concentration-dependent activity. The antioxidant activity was varied according to the examined material. It was obvious that caffeic acid and vitamin C showed the highest activity if compared with the propolis samples. El- Saff propolis had a higher antioxidant activity than Ismailia propolis, it showed a higher antibacterial activity against Staphylococcus aureus and a higher anti-fungal activity against Candida albicans. While the Ismailia propolis had a higher antibacterial activity against Escherichia coli, than El-Saff propolis. The chemical composition of propolis samples was investigated by GC/MS, where 75 compounds were identified, 22 being new for propolis. The Ismailia propolis was characterized by the presence of a highly significant amount of aromatic acid esters (47.3%) and triterpenoids (17.3%), while El-Saff propolis contained 3% and 1.9% respectively. The new esters belonged to 4-methoxyhydrocinnamic acid, hydroferulic acid and ferulic acid. El-Saff propolis had a very high significant amount (27%) of 2,6-bis-(pentanyloxy)-4-pentanylphenethanol, which is also a new compound for propolis.

Catalytic ketonization over oxide catalysts, Part VI.a Cross-ketonization of aliphatic and aromatic esters

Activity of 20 wt.% MO2/Al2O3 catalysts, where M = Mn, Ce and Zr has been studied in cross-ketonization of ethyl esters of aliphatic and aromatic acids in a flow system. Pentan-3-one and tridecan-7-one were formed in ketonization of pure aliphatic esters, ethyl propanoate and ethyl heptanoate. Benzene was obtained instead of diphenylmethanone as the product of ethyl benzoate transformations. Only two ketones, dialkyl and aralkyl, were obtained from the cross-ketonization of a mixture of aliphatic and aromatic esters. The highest yield of 1-phenyl-1-heptanone (70%) from ethyl heptanoate and ethyl benzoate was reached at 698 K in the presence of MnO2/Al2O3 catalyst. Under similar conditions cross-ketonization of a mixture of ethyl propanoate and ethyl benzoate led to 1-phenyl-1-propanone (60% at 673 K).

Determination of chemical composition of Turkish propolis.

The aim of the present work is to study the chemical composition of Turkish propolis. Propolis samples were collected from different regions of Turkey (Bursa, Erzurum-Askale, Gumushane-Sogutagil and Trabzon-Caglayan) in 1999. Ethanol extracts of propolis (EEP) were prepared for chemical analysis, using gas chromatograph coupled with mass spectrometry (GC-MS). Our findings show that propolis samples from Trabzon and Gumushane region have a similar chemical composition. In both samples aromatic acids, aliphatic acids and their esters, and also ketone derivatives are the main compound groups. The chemical composition of the single sample that was collected from Erzurum region shows a very different pattern than the other two samples. In this propolis, the main compounds are aromatic acid esters and alcohols. However, it contains a high amount of amino acids compared to the other samples. The other samples collected from three different region of Bursa City are rich with flavavones, aromatic acids and their esters, terpenoids, flavones and ketones.

Synthesis of D-Mannite Esters of Aliphatic and Aromatic Acids

Mono- and diesters of D-mannite with aliphatic acids and mixed diesters with aliphatic and aromatic acids were synthesized by transesterification of their methyl esters. The structures of the products are confirmed by PMR,13C NMR, and IR spectra

Interaction of 2-(2-azahetaryl)-3-oxo-4-chlorobutane nitriles with esters of aromatic amino acids

The reaction of 2-(2-azahetaryl)-3-oxo-4-chlorobutane nitriles with esters of aromatic acids was studied. A series of 1H,4H-3-(2-azahetaryl)pyrrolo[1,2-a] quinazoline-2,5-diones and 1-aryl-2-amino-3-(2-azahetaryl)-4-(5H)-oxopyrroles was obtained. The reaction of the latter with hydrazine and acetic anhydride was investigated.