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Yang Yanli - - 2009
A novel beta-cyclodextrin (beta-CD) derivative modified with a degradable and biocompatible oligo(lactic acid) (OLA) group, 6-oligo(lactic acid)cyclomaltoheptaose (6-OLA-beta-CD), was successfully synthesized and used as a chiral selector for the capillary electrophoretic (CE) resolution (R(s)) of several basic analytes. The primary purpose of the research was to explore the capability of ...
Offenberg John H - - 2009
Secondary organic carbon (SOC) concentrations in steady-state aerosol were measured in a series of alpha-pinene/NOx and one series of beta-caryophyllene/NOx irradiation experiments. The acidity of the inorganic seed aerosol was varied while the hydrocarbon and NOx concentrations were held constant in each series of experiments. Measurements were made for acidity ...
Sim??es-Pires Claudia A - - 2009
Bioguided fractionation of Syzygium cumini (Myrtaceae) bark decoction for antiplasmodial activity was performed, leading to the isolation of three known ellagic acid derivatives (ellagic acid, ellagic acid 4-O-alpha-L-2"-acetylrhamnopyranoside, 3-O-methylellagic acid 3'-O-alpha-L-rhamnopyranoside), as well as the new derivative 3-O-methylellagic acid 3'-O-beta-D-glucopyranoside. Activity investigation was based on the reduction of P. falciparum ...
Cossy Janine - - 2009
Beta-amino alcohols derived from natural amino acids have been used extensively as a powerful source of chirality. Transformation of the hydroxy group of these beta-amino alcohols into a good leaving group, by using trifluoroacetic anhydride, led to rearranged beta-amino alcohols in good yields and with high enantiomeric excesses. This rearrangement ...
Motojima Hideko - - 2009
The physicochemical and biological properties of fulvic acid extracted and purified from excess sludge and solubilized excess sludge were studied. Solubilization was introduced to improve the recovery rate of fulvic acid from the sludge. The structural features of fulvic acid from excess sludge and solubilized excess sludge were characterized by ...
Dedoussis George V - - 2009
OBJECTIVE: Adipose tissue contributes in energy, lipid homeostasis and inflammation, through the adipokines it releases. Our aim was to study the associations between adipose tissue (AT) fatty acid content, adipokines' expression in AT and PBMCs and BMI in children. METHODS: Thirty-one (17 male) healthy children aged 10.9+/-1.8years and of BMI ...
Begriche Karima - - 2010
beta-Aminoisobutyric acid (BAIBA) is a catabolite of thymine and antiretroviral thymine analogues AZT and d4T. We recently discovered that this beta-amino acid is able to enhance fatty acid oxidation and reduce body weight in mice through an increased production of leptin by the white adipose tissue (WAT). Furthermore, BAIBA could ...
Bourgoin-Voillard Sandrine - - 2009
The affinity of estradiol derivatives for the estrogen receptor (ER) depends strongly on nature and stereochemistry of substituents in C(11) position of the 17beta-estradiol (I). In this work, the stereochemistry effects of the 11alpha-OH-17beta-estradiol (III(alpha)) and 11beta-OH-17beta-estradiol (III(beta)) were investigated using CID experiments and gas-phase acidity (DeltaH degrees (acid)) determination. ...
Arantes Lucas Micquéias - - 2009
This study focused on the use of NMR techniques as a tool for the investigation of complex formation between proparacaine and cyclodextrins (CDs) or p-sulfonic acid calix[6]arene. The pH dependence of the complexation of proparacaine with beta-CD and p-sulfonic acid calix[6]arene was studied and binding constants were determined by (1)H ...
Haseleu Gesa - - 2009
Thermal treatment of the hop beta-acid colupulone under wort boiling conditions, followed by LC-TOF-MS and 1D/2D NMR spectroscopy, revealed cohulupone, hulupinic acid, nortricyclocolupone, two tricyclocolupone epimers, two dehydrotricyclocolupone epimers, two hydroxytricyclocolupone epimers, and two hydroperoxytricyclocolupone epimers as the major bitter-tasting beta-acid transformation products. Among these compounds, the chemical structures of ...
Samuel Reichel - - 2010
To reduce the recalcitrance and enhance enzymatic activity, dilute H(2)SO(4) pretreatment was carried out on Alamo switchgrass (Panicum virgatum). Ball-milled lignin was isolated from switchgrass before and after pretreatment. Its structure was characterized by (13)C, HSQC, and (31)P NMR spectroscopy. It was confirmed that ball-milled switchgrass lignin is of HGS ...
Bagri Priyanka - - 2009
Two new beta-sitosterol esters have been isolated from the flowers of Punica granatum Linn. (Punicaceae) along with the known compounds n-tricosane (3), n-heptacosanyl n-hexanoate (4), olean-5,12-dien-3beta-ol-28-oic acid (5), and olean-12-en-3beta-ol-28-oic acid (6). The structures of the new phytosterols have been elucidated as stigmast-5-en-3beta-ol-3beta-dodecanoate (beta-sitosterol laurate, 1) and stigmast-5-en-3beta-ol-3beta-tetradecanoate (beta-sitosterol myristate, ...
Tsuneyoshi Yousuke - - 2009
We previously demonstrated that beta-alanyl-branched chain amino acids have excitatory effects. Therefore, we named beta-alanyl-L-leucine, beta-alanyl-L-isoleucine and beta-alanyl-L-valine as Excitin-1, -2, and -3 , respectively. Since there is little known about the effects of Excitins, we clarified whether oral administration of Excitin-1 affects behavior in rats, alters the monoamine and ...
Saavedra Carlos - - 2009
The one-pot conversion of readily available alpha-amino acid into beta-amino acid derivatives was carried out in good yields. The method is a sequential process initiated by a tandem radical decarboxylation-oxidation reaction; the resulting acyliminium ion was trapped by silyl ketenes. Stoichiometric and catalytic versions of this reaction were developed and ...
Duffy Richard J - - 2009
A novel class of small spirocyclic heterocycles, spiroepoxy-beta-lactones (1,4-dioxaspiro[2.3]-hexan-5-ones), is described that exhibit a number of interesting reactivity patterns. These spiroheterocycles, including an optically active series, are readily synthesized by epoxidation of ketene dimers (4-alkylidene-2-oxetanones) available from homo- or heteroketene dimerization. An analysis of bond lengths in these systems by ...
Barghash Reham F - - 2009
A new class of C-glycosyl amino acids displaying a thiourea segment as a linker has been designed and synthesized by addition of peracetylated glycosylmethyl isothiocyanates to an amine-functionalized amino acid (N(alpha)-Fmoc-beta-amino-l-alanine). Three pairs of compounds with alpha- and beta-galacto, alpha- and beta-gluco, and alpha- and beta-manno configuration have been prepared ...
Stochmal Anna - - 2009
Three phenolic glycosides 5-O-{[5''-O-E-(4'''-O-threo-guaiacylglycerol)-feruloyl]-beta-apiofuranosyl-(1-->2)-beta-xylopyranosyl} gentisic acid, 5-O-[(5''-O-vanilloyl)-beta-apiofuranosyl-(1-->2)-beta-xylopyranosyl] gentisic acid and 1-O-[E-(4'''-O-threo-guaiacylglycerol)-feruloyl]-3-O-beta-galacturonopyranosyl glycerol were isolated and identified from the roots of Medicago truncatula together with four known 5-O-beta-xylopyranosyl gentisic acid, vicenin-2, hovetrichoside C and pterosupin identified for the first time in this species. Structural elucidation was carried out on the basis ...
Chaudhuri Prabir Kumar - - 2009
A new ursane triterpenoid ester, urs-12-en-3beta-O-9E,12E-octadecadienoate, was identified from the rhizomes of Nelumbo nucifera by spectral and chemical analyses along with the isolation of seven known compounds: palmitic acid, linoleic acid, 9E,12E,15E-octadecatrienoic acid, alpha-amyrin, beta-sitosterol, betulinic acid, and beta-sitosterol-3-O-glucoside.
Testero Sebastian A - - 2009
The unique hydrophobic surface patches in class D beta-lactamases presented an opportunity for designing two compounds, 6alpha-(1R-hydroxyoctyl)penicillanic acid and 6beta-(1R-hydroxyoctyl)penicillanic acid, as mechanistic probes of these enzymes. In a sequence of three synthetic steps from benzhydryl 6,6-dibromopenicillanate, the targeted compounds were prepared in a stereospecific manner.
Heck Tobias - - 2009
The growing demand for enantiomerically pure beta-amino acids to be used in the pharmaceutical industry and as fine chemicals requires the development of new strategies for their synthesis. The beta-aminopeptidases BapA from Sphingosinicella xenopeptidilytica 3-2W4, BapA from Sphingosinicella microcystinivorans Y2, and DmpA from Ochrobactrum anthropi LMG7991 are hydrolases that possess ...
Cordero Franca M - - 2009
1-(2-Pyrrolidinyl)cyclopropanecarboxylic acids (alpha-cyclopropyl-beta-homoprolines) were prepared by 1,3-dipolar cycloadditions of cyclic nitrones onto bicyclopropylidene followed by trifluoroacetic acid induced thermal fragmentative rearrangement. With the use of enantiopure pyrroline N-oxides derived from easily available chiral pool molecules, beta-homoprolines were formed with high stereocontrol. The incorporation of one of these new cyclic beta-amino ...
Conrad Jürgen - - 2009
The first phytochemical analysis of the aquatic macrophyte Stratiotes aloides afforded two new flavonoid glucuronides, luteolin 7-O-beta-D-glucopyranosiduronic acid-(1-->2)-beta-D-glucopyranoside (1) and chrysoeriol 7-O-beta-D-glucopyranosiduronic acid-(1-->2)-beta-D-glucopyranoside (2), as well as the new 2-(2-hydroxypentyl)-5-carboxy-7-methoxychromone (5) and chrysoeriol 7-O-beta-(6-O-malonyl)glucopyranoside (3), which has been assigned via NMR data for the first time. Additionally, free amino acids ...
Viney Mark E - - 2009
Nematodes are important parasites of humans and other animals. Nematode parasitism is thought to have evolved by free-living, facultatively developing, arrested larvae becoming associated with animals, ultimately becoming parasites. The formation of free-living arrested larvae of the nematode Caenorhabditis elegans is controlled by the environment, and involves dafachronic acid (DA) ...
Elfita Elfita - - 2009
Phytochemical investigations of four Garcinia spp. from Indonesia, i.e. Garcinia griffithii T. Anderson, Garcinia celebica L., Garcinia cornea L. and Garcinia cymosa K. Schum (Clusiaceae), have resulted in the isolation of a xanthone, 1,5-dihydroxy-3,6-dimethoxy-2,7-diprenylxanthone, 1,7-dihydroxyxanthone, isoxanthochymol, beta-sitosterol-3-O-beta-D-glucoside and stigmasterol-3-O-beta-D-glucoside from the stem bark of G. griffithii; friedelin and 3beta-hydroxy-23-oxo-9,16-lanostadien-26-oic acid ...
Metzner Linda - - 2009
The orally administered creatine analogue beta-guanidinopropionic acid (beta-GPA) decreases plasma glucose levels by increasing the sensitivity to insulin. This effect is based on a beta-GPA induced expression of mRNA and total protein content of the insulin-responsive glucose transporter GLUT4. Although the oral availability of beta-GPA is well established, the underlying ...
Michaux Julien - - 2009
Owing to their significant abundance in natural products, chiral beta,beta'-disubstituted alpha-amino acids remain an important synthetic objective. Emphasis has been focused in this critical review on the great diversity of enantio- and diastereoselective methodologies to reach these highly functionalized compounds. The oldest and cutting edge synthetic methods are described in ...
Kim Deog J - - 2009
Clavulanic acid is a member of the beta lactam family of antibiotics with little or no intrinsic antibacterial activity of its own; instead, it is used to enhance the activity of antibiotics by blocking bacterial beta-lactamases. Because clavulanic acid by itself is very safe, orally active and shows good brain ...
Tava Aldo - - 2009
The reinvestigation of saponin composition from Medicago arabica from Italy allowed the detection of nineteen (1-19) saponins. All of them were purified by reverse-phase chromatography and their structures elucidated by spectroscopic and spectrometric (1D and 2D NMR; ESI-MS/MS) and chemical methods. Fourteen were known saponins, previously found in other plants ...
Hang Jianfeng - - 2009
The beta,gamma-unsaturated amino acids are versatile chiral building blocks and biologically interesting compounds. The asymmetric synthesis of beta,gamma-unsaturated amino acids presents a challenging task as these compounds are labile toward racemization as well as the undesirable double bond isomerization. An efficient, general and mild kinetic resolution with readily accessible and ...
Innocenti Alessio A Università degli Studi di Firenze, Polo Scientifico, Sesto Fiorentino, Florence, - - 2009
Inhibition of the beta-carbonic anhydrases (CAs, EC 4.2.1.1) from the pathogenic fungi Cryptococcus neoformans (Can2) and Candida albicans (Nce103) with a series of aromatic, arylalkenyl- and arylalkylboronic acids was investigated. Aromatic, 4-phenylsubstituted- and 2-naphthylboronic acids were the best Can2 inhibitors, with inhibition constants in the range of 8.5-11.5microM, whereas arylalkenyl ...
Kaji Y - - 2009
BACKGROUND: D-beta-aspartic acid residues, which are biologically uncommon, have been reported to accumulate in various proteins of the living body with age. In the present study, D-beta-aspartic acid-containing proteins were found to be localised in pingueculae, which represent one of the most prominent age-related ocular changes. METHODS: Surgical specimens of ...
Tang Kewen - - 2009
This article reports a new chiral separation method-biphasic recognition chiral extraction for the separation of mandelic acid enantiomers. Distribution behavior of mandelic acid enantiomers was studied in the extraction system with O,O'-di-benzoyl-(2S,3S)-4-toluoyl-tartaric acid (D-(+)-DTTA) in organic phase and beta-CD derivatives in aqueous phase, and the influence of the types and ...
Morgan Noel G - - 2009
PURPOSE OF REVIEW: The rising incidence of type 2 diabetes is due, in part, to the detrimental effects of certain fatty acids on pancreatic beta-cell function and viability. The present review examines recent advances in the understanding of the molecular mechanisms by which fatty acids influence the life and death ...
Hyyryläinen Anna R M - - 2009
Chiral differentiation of four enantiomeric pairs of beta-amino acids, cis-(1R,2S)-, cis-(1S,2R)-, trans-(1R,2R)-, and trans-(1S,2S)-2-aminocyclopentanecarboxylic acids (cyclopentane beta-amino acids), and cis-(1R,2S)-, cis-(1S,2R)-, trans-(1R,2R)-, and trans-(1S,2S)-2-aminocyclohexanecarboxylic acids (cyclohexane beta-amino acids) was performed successfully by using host-guest complexes and ion/molecule reactions. The experiments were conducted by using electrospray ionization Fourier transform ion cyclotron ...
Liou Benjamin - - 2009
The hydrolysis of glucosylceramide by acid beta-glucosidase proceeds via a two-step, double displacement mechanism that includes cleavage of the O-beta-glucosidic bond, enzyme-glucosylation and, then, enzyme-deglucosylation. Two residues that may impact this cycle are N370 and E235. The N370S mutant enzyme is very common in Gaucher disease type 1 patients. Homology ...
Tabopda Turibio Kuiate - - 2009
Antibacterial bioassay-guided fractionation of the methanol extract of the stem bark of Terminalia superba led to the isolation of four new triterpene glucosides (1-4) which were characterized as 2 alpha,3 beta-dihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (1), 2 alpha,3 beta, 21 beta-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (2), 2 alpha,3 beta, 29-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (3) and ...
Bhujbal Namdeo N - - 2009
Synthesis of catechuic acid (1) and ethyl 2,4,5-trihydroxybenzoate (2) from D-glucose-derived beta-ketoester is described. The polyhydroxylated beta-ketoester obtained from the hydrolysis of sugar beta-ketoester 3 was subjected to an aldol-type condensation to get 4 that on enolization, dehydration, and hydrogenation afforded ethyl 2,4,5-trihydroxybenzoate (2). On the other hand, hydrogenation of ...
Fustero Santos - - 2009
The first general approach for the diastereoselective formation of a variety of optically pure anti-beta-fluoroalkyl beta-amino acid derivatives is described. The process relies on the stereocontrolled reaction, mediated by a remote sulfoxide, of fluorinated imines with sulfinylated benzyl carbanions, which are used as synthetic equivalents of chiral ester enolates.
Luo Jie-Min - - 2009
Guided by nature: A flexible and epimerization-free approach for the asymmetric syntheses of melleumin A and four analogues of melleumins A and B was developed, which allowed confirming the stereochemistry at C-4 of melleumin A, and revealed that the unnatural 4-epi-melleumin B possesses a modest inhibitory activity on Wnt signaling. ...
Hiraishi Tomohiro - - 2009
Pedobacter sp. KP-2 can degrade and metabolize thermally synthesized alpha,beta-poly(D,L-aspartic acid) (tPAA), which contains 70% of unnatural beta-amide units, with high-molecular-weight. In this study, gene cloning and molecular characterization of PAA hydrolase-1 from KP-2 was carried out. Gene analysis reveals that deduced amino acid sequence of the enzyme shows a ...
Métro Thomas-Xavier - - 2009
Beta-amino alcohols derived from alpha-amino acids have been extensively used as a powerful source of chirality. Transforming the alcohol moiety into a good leaving group has allowed the rearrangement of these beta-amino alcohols and the introduction of a large number of nucleophiles through the anchimeric participation of the nitrogen atom. ...
North Michael - - 2009
Hidden talent: Often perceived to be too thermodynamically and kinetically inert to be a useful chemical feedstock, carbon dioxide adds to allenes under exceptionally mild reductive conditions in the presence of a palladium pincer complex to give beta,gamma-unsaturated carboxylic acids (see scheme). This transformation is discussed in the context of ...
Kulakovskaya Tatyana - - 2009
Basidiomycetous yeasts Cryptococcus humicola and Pseudozyma fusiformata secrete cellobiose lipids into the culture broth. In the case of Cr. humicola, 16-(tetra-O-acetyl-beta-cellobiosyloxy)-2-hydroxyhexadecanoic acid was defined as major product and 16-(tetra-O-acetyl-beta-cellobiosyloxy)-2,15-dihydrohexadecanoic acid was defined as minor product, while Ps. fusiformata secreted mainly 16-[6-O-acetyl-2'-O-(3-hydroxyhexanoyl)-beta-cellobiosyloxy)-2,15-dihydroxyhexadecanoic acid. These compounds exhibit similar fungicidal activities against different ...
Kohl Ingrid - - 2009
What's the matter? The laboratory Raman spectra for carbonic acid (H(2)CO(3)), both for the beta-polymorph and its amorphous state, are required to detect carbonic acid on the surface of the pole caps of Mars in 2009, when the Mars Microbeam Raman Spectrometer lands on the planet. The picture shows a ...
Nahrwold Markus - - 2009
Novel procedures have been developed to condense benzaldehyde effectively with beta-amino acid amides to cyclic benzyl aminals. Double carbamate protection of the heterocycle resulted in fully protected chiral beta-alanine derivatives. These serve as universal precursors for the asymmetric synthesis of functionalised beta(2)-amino acids containing acid-labile protected side chains. Diastereoselective alkylation ...
Li Rui - - 2009
The present work was aimed at the influence of ethanol on the complex formation of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) with oleanolic acid (OA) and ursolic acid (UA), two insoluble isomeric triterpenic acids. Phase solubility studies were carried out to evaluate the solubilizing power of HP-beta-CD, in association with ethanol, toward OA and ...
Tsakris Athanassios - - 2009
The worldwide increase in the occurrence and dissemination of KPC beta-lactamases among gram-negative pathogens makes critical the early detection of these enzymes. Boronic acid disk tests using different antibiotic substrates were evaluated for detection of KPC-possessing Klebsiella pneumoniae isolates. A total of 57 genotypically confirmed KPC-possessing K. pneumoniae isolates with ...
Saito Norio - - 2008
The structures of 11 acylated cyanidin 3-sophoroside-5-glucosides (pigments 1-11), isolated from the flowers of Iberis umbellata cultivars (Cruciferae), were elucidated by chemical and spectroscopic methods. Pigments 1-11 were acylated with malonic acid, p-coumaric acid, ferulic acid, sinapic acid and/or glucosylhydroxycinnamic acids. Pigments 1-11 were classified into four groups by the ...
Choi Hyun-Sik - - 2008
Three new lupane-type saponins, acankoreosides F--H (1--3) were isolated from the methanol extract of the leaves of Acanthopanax koreanum NAKAI. The structures of these three saponins were established by chemical and spectroscopic analysis as 3alpha,30-dihydroxylup-20(29)-en-23,28-dioic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester (1), 3alpha,30-dihydroxylup-23-al-20(29)-en-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester (2), and (20S) 3alpha-hydroxylup-23-al-28,29-dioic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester ...
Khasanova Tatyana V - - 2008
This paper introduces polar and hydrophobic variants of the unnatural amino acid Hao, which mimics the hydrogen-bonding functionality of one edge of a beta-strand. In these variants, the methyl side chain of Hao is replaced with acidic, basic, and hydrophobic groups. These modifications can impart improved solubility and additional side-chain ...
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