Search Results
Results 301 - 350 of 918
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Petersson Karsten - - 2004
Nucleobase containing compounds might constitute a potential alternative to conventional antibiotics in the treatment of Helicobacter pylori infections. N4-alkyloxycarbonyl-cytosine derivatives were synthesized and subjected to basic physicochemical characterisation including assessment of hydrolytic stability in various matrices. pH-rate profiles of selected compounds (range 0-12) were constructed. Hydrolysis of the derivatives in ...
Kovácik Vladimír - - 2004
Fragmentation mechanisms of electrospray ionization (ESI) mass spectrometry of aldobiuronic and pseudoaldobiuronic acid derivatives were elucidated by multistage mass spectrometric (MS(n), n = 2-5) measurements of selected ions. Characteristic under the conditions of ESI-MS analysis is the production of alkali metal (Na and K) cationized adducts. The probability the of ...
Kamiński Z J - - 2004
Symmetric, trisubstituted derivatives of cyanuric and isocyanuric acid 3a-e and 4a-e, respectively have been prepared by treatment of cyanuric chloride 1 with appropriate terpenic alcohols 2a-e. Under less basic conditions involving treatment of appropriate alcohols 2a-e with metallic sodium, less polar cyanuric acid derivatives 3a-e were obtained in 74-85 yield. ...
Contreras-Torres Flavio F - - 2005
Imidazo[1,2-a]pyrazine-3,6-diones and imidazo[1,2-a]imidazo[1,2-d]pyrazine-3,8-diones can be produced by pyrolysis of simple amino acids. While such bicyclic and tricyclic amidines were detected and characterized by IR spectroscopy for some alpha-substituted amino acids, the parent systems composed of glycine fragments are unknown up to now. IR spectra for five amidines derived from glycine ...
da Cunha Fernanda M - - 2004
Caffeic acid and some of its derivatives such as caffeic acid phenetyl ester (CAPE) and octyl caffeate are potent antioxidants which present important anti-inflammatory actions. The present study assessed the in vitro and in vivo effects of five caffeic acid derivatives (caffeic acid methyl, ethyl, butyl, octyl and benzyl esters) ...
Csuk René - - 2004
A series of antiviral compounds consisting of an intercalating acridine derived part, a spacer region and a reactive EDTA-derived conjugate was synthesized in an easy sequence starting from 1,omega-alkyldiamines. As shown in model screenings, in the presence of ascorbic acid the Fe-complexes of these compounds reduced the phage-titer of MS2-phages ...
de Moura Rute Mendonça Xavier - - 2004
The antimicrobial activity of ethanolic extract and pure compounds of Gomphrena celosioides have been screened by Kirby-Bauer method. Quantitative determination of 4-hydroxy-3-methoxy-benzoic acid in stems, leaves, flowers and roots was established by TLC-densitometry. Results showed significant activity against Staphylococcus aureus and Salmonella typhi. There were no significant differences in the ...
Chollet Jean-François - - 2004
A series of derivatives of the phenylpyrrole fungicide fenpiclonil was synthesized in which a carboxyl group was present at various sites of this non-phloem-mobile molecule. Using the Kleier model, all these acidic analogues were predicted to be moderately phloem-mobile, especially the N-substituted derivatives. One of these latter molecules, N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole, exhibited ...
Carić Dejana - - 2004
The absorption and fluorescence spectra of indole-3-acetic acid (1), a plant growth regulator (auxin) and experimental cancer therapeutic, 29 ring-substituted derivatives and the 7-aza analogue (1H-pyrrolo[2,3b]pyridine-3-acetic acid) are compared. Two to four absorbance maxima in the 260-310-nm range are interpreted as overlapping vibronic lines of the 1La<--1A and 1Lb<--1A transitions. ...
Nyasse B - - 2004
A new kolavic acid derivative known from spectroscopic analyses as monomethyl ester-15-kolavic acid was isolated from the stem bark of Entada abyssinica, a plant traditionally used in West and East Africa for the management of sleeping sickness. The new derivative showed a strong and selective inhibitory activity on the GAPDH ...
Smith James M - - 2004
The potentially prebiotic synthesis of ribo-nucleotides by stepwise pyrimidine nucleobase assembly on arabinose-3-phosphate derivatives has been demonstrated in previous work. Consideration of the provenance of pentose phosphates, by aldolisation or sugar phosphorylation, suggested that 2-phosphate derivatives might be generated more easily than 3-phosphate derivatives. In the 2-phosphate series, nucleobase-assembly chemistry ...
Sekine Mitsuo - - 2004
To study the structure-activity relationship of phosmidosine, a variety of phosmidosine derivatives 9a-g were synthesized by condensation of N-diisopropyl N'-(N-tritylprolyl)phosphorodiamidite 6 with appropriately protected nucleoside derivatives 7a-g. As the result, replacement of the 7,8-dihydro-8-oxoadenine base by adenine and 6-N-acetyladenine did not affect the antitumor activity. However, phosmidosine derivatives containing uracil, ...
N'goka Victor - - 2004
Nipecotic acid derivatives bearing an aryl iminoxymethyl side chain at the position 6 were synthesised and tested for their GABA uptake inhibitory properties. Contrarily to the N-substituted derivatives 2, 3 the introduction of the oxime function in the side chain of analogues of the active nipecotic derivative 4 does neither ...
Verma Rajeshwar P - - 2004
Caffeic acid and its derivatives are already known to possess a wide range of biological activities. We have developed quantitative structure-activity relationships (QSARs) for different series of caffeic acid derivatives (including caffeic acid) in order to understand the chemical-biological interactions governing antitumor activity against six different tumor cell lines, nitric ...
Okamoto Shigeru - - 2004
Two new decalin derivatives, eujavanoic acids A (1) and B (2), were isolated from Eupenicillium javanicum, along with several compactin derivatives. The structures of 1 and 2 were determined by spectroscopic methods and modified Mosher's method. The side chain (2-methylbutanoyloxy) and acid functionalities of compactin derivatives were necessary to show ...
Ashby Michael T - - 2004
Sulfenyl thiocyanate (RSSCN) derivatives of penicillamine (PENSCN) and glutathione (GSSCN) have been synthesized in situ at pH = 0 from equilibrium mixtures that consists of hypothiocyanous acid (HOSCN), thiocyanogen ((SCN)2), and trithiocyanate ((SCN)3-). The electrophilic thiocyanating agent N-thiocyanatosuccinimide (NTS) also reacts with PEN and GSH to yield the corresponding RSSCN ...
Pan Yanbin - - 2004
N-Acetyl-D-neuraminic acid (NeuNAc) aldolase is an important enzyme for the metabolic engineering of cell-surface NeuNAc using chemically modified D-mannosamines. To explore the optimal substrates for this application, eight N-acyl derivatives of D-mannosamine were prepared, and their accessibility to NeuNAc aldolase was quantitatively investigated. The N-propionyl-, N-butanoyl-, N-iso-butanoyl-, N-pivaloyl-, and N-phenylacetyl-D-mannosamines ...
Miron T - - 2004
Allicin (diallylthiosulfinate), the active substance of garlic, has been shown to possess a variety of biological activities. Mechanistic and pharmacokinetic studies of allicin and its derivatives raise the need for a labeled compound. However, labeling of this volatile and unstable liquid requires delicate handling. Here, we describe a simple method ...
Andersen Claus Yding - - 2004
The clinical efficacy of commercial gonadotrophin preparations has been the subject of an intense debate during recent years. Arguments have primarily focused on the origin of FSH activity (urine versus recombinant derived) and whether the preparation included LH-like activity. FSH isoform composition has received little or no attention, and is ...
Gesell Manuela - - 2004
The ability of the imperfect soil fungus Paecilomyces lilacinus to transform the environmental pollutant dibenzofuran was investigated. Transformation of dibenzofuran and related derivatives lead to 14 products, which were identified by UV spectroscopy, mass spectrometry, and proton nuclear magnetic resonance spectroscopy. Biotransformation was initiated by two separate hydroxylation steps, leading ...
Zvilichovsky Gury - - 2004
The nucleophilic ring opening of the isoxazolone ring in 2-oxo-3-phenylisoxazolo[2,3-a]pyrimidine derivatives by optically active amino acid amides and ephedrine led to pyrimidinylmethylamino acid amides. Using amides of different L-amino acids and (-)-ephedrine resulted in different degrees of stereoselectivity. The degree of streoselectivity depended mostly on the nucleophile used. When applying ...
Almeida Maria Rosário - - 2004
In familial amyloidotic polyneuropathy, TTR (transthyretin) variants are deposited as amyloid fibrils. It is thought that this process involves TTR tetramer dissociation, which leads to partially unfolded monomers that aggregate and polymerize into amyloid fibrils. This process can be counteracted by stabilization of the tetramer. Several small compounds, such as ...
Hany Roland - - 2004
The side-chain double bonds of bacterial poly[3-hydroxyalkanoate-co-3-hydroxyalkenoate] (PHAE, 1) were transformed into thioether bonds (derivative 2) via the radical addition reaction of 11-mercapto-1-undecanol. The terminal hydroxy functionalities of derivative 2 were subsequently esterified with cinnamic acid (derivative 3), sulfatized with ClSO(3)H (derivative 4), or coupled with tert-butyldimethylsilyl-protected coumaric acid, to ...
Jikumaru Yusuke - - 2004
Several types of jasomonic acid (JA) derivatives, including JA--amino acid conjugates, a JA--biotin conjugate, a JA--dexamethasone heterodimer, and a JA-fluoresceine conjugate, were prepared as candidates for molecular probes to identify JA--binding proteins. These JA derivatives, excepting the JA--fluoresceine conjugate, exhibited significant biological activities in a rice seedling assay, a rice ...
Céspedes Carlos L - - 2004
The methanol extract from the aerial parts of Roldana barba-johannis (Asteraceae) afforded sargachromenol, sargahydroquinoic acid, and sargaquinoic acid. These natural products and their corresponding acetylated and methylated derivatives showed insecticidal and insect growth regulatory activities against the Fall Armyworm [Spodoptera frugiperda J.E. Smith, (Lepidoptera: Noctuidae)], an important insect pest of ...
Mukherjee Rama - - 2004
New 3-O-acyl, 3-benzylidene, 3-hydrazone, 3-hydrazine, 17-carboxyacryloyl ester derivatives of betulinic acid (2-6, 8-11, 13, 17, 18, 21, and 22) were synthesized and evaluated in vitro for anti-angiogenic activity on endothelial cell cytotoxicity, specificity, and tube-formation ability. All derivatives reported here showed IC(50)<4 microg/mL. Compounds 3, 9, 10, 17, 21, and ...
Zanetta Jean-Pierre - - 2004
C-mannosylation of Trp residue is one of the most recently discovered types of glycosylation, but the identification of these mannosylated residues in proteins is rather tedious. In a previous paper, it was reported that the complete analysis of all constituents of glycoproteins (sialic acids, monosaccharides, and amino acids) could be ...
Yanai Koji - - 2004
PF1022A, a cyclooctadepsipeptide possessing strong anthelmintic properties and produced by the filamentous fungus Rosellinia sp. PF1022, consists of four alternating residues of N-methyl-L-leucine and four residues of D-lactate or D-phenyllactate. PF1022A derivatives obtained through modification of their benzene ring at the para-position with nitro or amino groups act as valuable ...
Rivière Johann - - 2004
Oxidation products of cytosine, including 5-hydroxycytosine and 5-hydroxyuracil, are highly susceptible to subsequent oxidation. Here, the oxidation products of 5-hydroxy-2'-deoxyuridine have been studied by NMR and MS analyses. The initial products were diastereomers of isodialuric acid nucleoside. These products subsequently decomposed into corresponding dialuric acid derivatives at neutral pH. The ...
Krohn Karsten - - 2004
Six known metabolites, two new isocoumarins 4 and 8, and one new highly substituted benzoic acid derivative 9 were isolated from the ethyl acetate culture extract of a fungal endophyte, Scytalidium sp. In addition, another new benzoic acid 10 with an unusual 1,2-dicarbonyl side chain was indirectly identified from its ...
Hernández J Nicolás - - 2004
The consecutive treatment of N-Cbz amino protected compounds with LiHMDS and CbzCl provides a practical method for the preparation of N,N-benzyloxycarbamoyl (N,N-di-Cbz) derivatives in good yield. When alpha-amino acids are used the protection occurs without racemization. The method is compatible with a wide range of other functional and protecting groups. ...
Watanabe Yutaka - - 2004
Contrary to the usually accepted phenomena, an optically heterogeneous 1:1 diastereomixture of DS and LS and a racemate of LS and DR obtained, respectively, from a racemic myo-inositol derivative and (S)- and racemic O-acetylmandelic acid formed stronger organogels, especially with aromatic fluids, than those formed from homochiral isomers, DS and ...
Dong Mi-Sook - - 2004
The structural relationship of 16 asiatic acid (AA) derivatives, including AA and asiaticoside (AS) to cytotoxicity and anti-hepatofibrotic activity in HSC-T6 cells, were investigated. Cytotoxicities of AA derivatives varied from 5.5 microM to over 2000 microM of IC50 depending on AA functional group modifications. Substituting the hydroxyl group at the ...
Pipino Sandra - - 2004
Three chromogenic products of AHTN have been detected after photo-oxidation and shown to react with glycine or albumin, giving rise first to a blue color, followed by pink and, finally, a dark green colour. The absorption spectrum associated with the late green colour showed an increased absorbance in the long ...
Tremblay Steve - - 2004
Brevifoliol is a natural diterpene isolated from Taxus baccata Nutt. A series of brevifoliol 1 derivatives, 2-8 and 10, were prepared for characterization and semisynthesis purposes and included the introduction of acetyl, Troc, and TES groups at C-5 and C-13. Derivatives 16-20 of 5-acetylbrevifoliol 2 were obtained via esterification with ...
Xie Dong - - 2004
It is known that unreacted 2-hydroxyethyl methacrylate (HEMA) in current resin modified glass ionomer cements (RMGICs) shows potential cytotoxicity to pulp and surrounding tissues. Elimination of HEMA could make RMGICs more attractive for dental applications. In this research, novel six acrylate and methacrylate derivatives of amino acids were synthesized, characterized ...
Schram Karl - - 2004
Samples of 1,3- (1) and 1,5-dicaffeoylquinic acid (2) and their hexaacetate derivatives were examined using positive and negative electrospray ionization mass spectrometry and tandem mass spectrometry. Differences in the various spectra allow the discrimination of each of the isomers. Specific losses in the spectra of 2 also permit the identification ...
Shidoji Yoshihiro - - 2004
Geranylgeranoic acid (GGA; all-trans 3,7,11,15-tetramethyl-2,6,10,14-hexadecatetraenoic acid) has been shown to induce apoptosis in a human hepatoma-derived cell line, HuH-7. We aimed not only to confirm the apoptogenic properties of GGA and its derivatives, but also to search for natural GGA in medicinal herbs. GGA induced apoptosis in human hepatoma-derived cell ...
Kota Parvathi - - 2004
Although S-adenosyl-l-methionine (SAM) dependent caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase (COMT) is one of the key enzymes in lignin biosynthesis, the present work demonstrates that alfalfa COMT methylates benzaldehyde derivatives more efficiently than lignin pathway intermediates. 3,4-Dihydroxy, 5-methoxybenzaldehyde and protocatechuic aldehyde were the best in vitro substrates for OMT activity in extracts ...
Hanczkó R - - 2004
The stability and characteristics of the C6-C8 n-aliphatic and phenylethylamines have been investigated as their o-phthaldialdehyde (OPA)/3-mercaptopropionic acid, OPA/N-acetyl-L-cysteine, OPA/2-mercaptoethanol and OPA/ethanethiol derivatives. Stoichiometric studies have been followed by photodiode array and fluorescence detection, simultaneously, while the composition of derivatives was confirmed by on line HPLC-electrospray ionization (ESI)-MS measurements. All ...
Xu Shangjie - - 2004
A novel diamino-substituted hypocrellin derived from hypocrellin B (HB) was synthesized by a mild method. The red absorption of the resulting product was significantly enhanced relative to the parent hypocrellins and any other hypocrellin derivatives, and the active oxygen species generating abilities were enhanced distinctly, which will remarkably improve its ...
Kosíková Bozena - - 2004
The ability of the yeast, Sporobolomyces roseus, isolated from leafy material, to modify lignin derived from beechwood pulping was examined by FTIR and 13C NMR spectroscopy, which revealed oxidative cleavage of the Calpha-Cbeta linkages between lignin units. Using veratryl alcohol as a model substrate confirmed that Sp. roseus could oxidize ...
Luppi B - - 2004
Benzophenone-3 (BZP) or oxybenzone is widely used in many cosmetic formulations, such as sunscreen lotions or emulsions, shampoos and hair sprays. The nature of the vehicle used can enhance or block the percutaneous absorption of UV filter. In this work, we hydrophobically modified polyvinylalcohol 10 000 (PVA) with fatty acids ...
Brtko J - - 2004
Kojic acid (5-hydroxy-2-hydroxymethyl-4-pyranone) represents an attractive polyfunctional skeleton for development of biologically active compounds. The authors prepared a great variety of kojic acid derivatives and selected biological properties have been studied. Thus, kojic acid derivatives are promising compounds that might advantageously be used in human and/or veterinary medicine and also ...
Matos M Agostinha R - - 2004
The standard (p(o)= 0.1 MPa) molar energies of combustion in oxygen, at T= 298.15 K, of four 1,3-benzodioxole derivatives (sesamol, piperonyl alcohol, piperonylic acid and homopiperonylic acid) were measured by static bomb calorimetry. The values of the standard molar enthalpies of sublimation, at T= 298.15 K, were derived from vapour ...
Locke Darren - - 2004
To facilitate the use of oligosaccharides as analytical tools in biological studies, we have designed, synthesized, and conjugated to maltosaccharides a novel series of homologous small fluorescent moieties that differ in formal charge. These moieties are amide derivatives of anthranilic acid: uncharged N-(2-aminobenzoyl)glycinamide (ABGlyAmide; 2), acidic N,N-dimethyl-N(')-(2-aminobenzoyl)ethylenediamine (ABGlyDIMED; 3), and ...
Wang Qin - - 2004
Derivatives of somatostatin (SST) represent the most important peptides for receptor targeting in oncological applications. Whereas the pharmacophor in somatostatin receptor-affine substances has been thoroughly investigated, the influence of modifications at the N-terminal has not yet been systematically studied. In order to investigate the influence of hydrophilic versus lipophilic modifications ...
Rontani J-F - - 2004
The electron ionization (EI) mass spectral fragmentation of omega-hydroxycarboxylic and omega-dicarboxylic acid trimethylsilyl derivatives was investigated. The mass spectra of these compounds exhibited fragment ions resulting from classical fragmentation of the trimethylsilyl ether and ester groups, and others resulting from the interactions between the two functionalities (m/z 147, 204, 217, ...
Monsur Ali Md - - 2004
We have previously demonstrated that the phenylsulfide and phenylsulfoxide derivatives of 2-amino-6-vinylpurine exhibit efficient cross-linking with high selectivity towards cytidine through synchronous activation within duplex. In this study, we synthesized their conjugates with PEG for possible application to in vitro as well as in vivo antisense agents. Thus, the ODN ...
Berardini Nicolai - - 2004
Polyphenolics were extracted from peels, pulp and kernels of mango fruits (Mangifera indica L. cv. 'Tommy Atkins') and characterized by high-performance liquid chromatography/electrospray ionization mass spectrometry. In the peel 18 gallotannins and five benzophenone derivatives were detected which were tentatively identified as galloylated maclurin and iriflophenone glucosides. Twenty-one and eight ...
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