A catalytic asymmetric procedure for the preparation of beta-amino acids (specifically beta-substituted aspartic acid derivatives) is reported. The cinchona alkaloid catalyst benzoylquinine (BQ) mediates up to five distinct steps of a reaction pathway, all in one reaction vessel. The products of this reaction, highly optically enriched beta-substituted aspartic acid derivatives, ...

[reaction: see text] The stereoselective synthesis of novel alpha-epoxy-beta-amino acids is described by a route that combines the chemistry of oxazolinyloxiranyllithiums with that of nitrones. The intermediate trioxadiazadispiro[2.0.4.3]undecanes 4 have been isolated and converted by hydrolysis into epoxy-5-isoxazolidinones 5 which can be transformed into the alpha-epoxy-beta-amino acids 8 by N-O ...

Important secondary metabolites, present in hops (Humulus lupulus L.), include alpha-acids and beta-acids, which are essential for the brewing of beer, as well as the prenylated chalcones, desmethylxanthohumol, and xanthohumol, which exhibit interesting bioactive properties. Their formation and accumulation in five selected hop varieties, Wye Challenger, Wye Target, Golding, Admiral, ...

[reaction: see text] A novel approach to alpha,alpha-disubstituted-beta-amino acids (beta(2,2)-amino acids) was employed in the synthesis of a series of 3-(pyrrolidin-1-yl)propionic acids possessing high affinity for the CCR5 receptor and potent anti-HIV activity. The rat pharmacokinetics for these new analogues featured higher bioavailabilities and lower rates of clearance as compared ...

The retention mechanism for a series of D,L-dansyl amino acids in high-performance liquid chromatography is investigated using a teicoplanin stationary phase and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as the mobile phase additive (0-16mM). A theoretical treatment is developed to determine the HP-beta-CD influence on the equilibrium between the teicoplanin phase and the aqueous ...

A bacterial strain producing a beta-lactam antibiotic acylase, able to hydrolyze ampicillin to 6-aminopenicillanic acid more efficiently than penicillin G, was isolated from soil and characterized. The isolate was identified as Achromobacter sp. using the phenotypic characteristics, composition of cellular fatty acids and 16S rRNA gene sequence. The enzyme synthesis ...

Prolonged exposure to free fatty acids induces beta-cell cytotoxicity. We investigated whether this fatty-acid-induced cytotoxicity is affected by high glucose levels. In clonal beta-cell HIT-T15, palmitate-induced cytotoxicity was potentiated depending on elevated glucose concentrations due to increased apoptosis without cytotoxic effects of high glucose per se. This palmitate cytotoxicity was ...

The trisaccharide, 3-aminopropyl 5-acetamido-3,5-dideoxy-D-glycero-alpha-D-galacto-2-nonulopyranosylonic acid-(2-->3)-beta-D-galactopyranosyl-(1-->4)-2-acetamido-2-deoxy-beta-D-glucopyranoside has been synthesized chemoenzymatically for the first time. First, the acceptor, 3-aminopropyl beta-D-galactopyranosyl-(1-->4)-2-acetamido-2-deoxy-beta-D-glucopyranoside was synthesized in a conventional chemical manner, and then it was coupled with CMP-sialic acid using alpha-(2-->3)-(N)-sialyltransferase to afford the desired trisaccharide by an enzymatically stereocontrolled manner.

[reaction: see text] A variety of beta-amino-gamma-keto acids were prepared in four steps from commercially available l-homoserine. The reaction sequence is highlighted by a Ni-catalyzed Grignard addition to a N-protected derivative of l-homoserine. One of the beta-amino-gamma-keto acids was then used to create a beta-peptide trimer composed solely of beta-amino-gamma-keto ...

We have demonstrated that the high yields and selectivities of 1,3-dipolar cycloadditions can be translated into facile stereoselective syntheses of a diverse array of beta-amino acids, key components of bioactive natural products, beta-lactams, and peptidomimetics. Simply by selecting different combinations of three readily available starting materials (an oxime, a chiral ...

Nine triterpenoid saponins were isolated from the leaves and stems of Schefflera arboricola. The saponins were characterised, on the basis of chemical and spectral evidence, as 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid, 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] echinocystic acid, 3-O-[beta-D-apiofuranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-ramnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic ...

In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly ...

Elevated production of hydrogen peroxide (H2O2) in the central nervous system has been implicated in the pathogenesis of several neurodegenerative diseases, including Parkinson's disease, ischemic reperfusion, stroke, and Alzheimer's disease. Pyruvic acid has a critical role in energy metabolism and a capability to nonenzymatically decarboxylate H2O2 into H2O. This study ...

Biphenylylacetic acid (BPAA) was linked to the free hydroxyl group of 2,6-di-O-methyl-beta-Cyclodextrin (DM-beta-CyD) through an ester linkage to obtain the site specific release of the drug to the colon. The conjugate at 1:1 mole ratio was separated from the reaction mixture by semipreparative reverse-phase HPLC and characterized by 1H-NMR, 13C-NMR, ...

1R-(-)-myrtenal was tested as a chiral derivatising agent for the determination of the enantiomeric purity of aliphatic primary amines, beta-aminoalcohols, beta-diamines and alpha-amino-acids. Derivatisation procedure consists in mixing one equivalent each of the amine and 1R-(-)-myrtenal directly into the nuclear magnetic resonance (NMR) tube before addition of the appropriate deuterated ...

2H-Pyran-2-ones 1 were transformed with various hydrazines into (E)- or (Z)-alpha, beta-didehydro-alpha-amino acid (DDAA) derivatives 4 (and 7) containing a highly substituted pyrazolyl moiety attached at the beta-position. With heterocyclic hydrazines, the products 4 were accompanied also by decarboxylated enamines E-6. In order to separate (E/Z)-mixtures of acids, they were ...

The seeds and one to three years old plants of Asian ginseng (Panax ginseng C.A. Meyer) were analyzed for their free amino acid contents. The neuro-excitatory beta-ODAP (beta-N-oxalyl-L-alpha,beta-diaminopropionic acid), suggested to be the cause of the crippling neurolathyrism, was the major component in the seed extract (70% of the total ...

The lipids extracted with CHCl(3)/MeOH mixtures from mycelium of the lower filamentous fungus Absidia corymbifera F-295 were found to contain three glycolipids. Based on the IR, 1H and 13C NMR spectra, plasma-desorption ionisation (PDI) mass spectra as well as chemical degradation results, the glycolipids were established to be 1-O-beta-D-glucopyranosyl-2-N-(2'-D-hydroxyhexadecanoyl)-9-methylsphinga-4(E),8(E)-dienine (glucosyl ...

Two new triterpenoid saponins, 3beta-O-beta-D-xylopyranosyl (1 --> 3)-alpha-L-rhamnopyranosyl-pyrocincholic acid 28-O-beta-D-glucopyranosyl (1 --> 6)-beta-D-glucopyranosyl ester (1), and 3beta-O-beta-D-xylopyranosyl(l --> 3)-alpha-L-rhamnopyranosyl-cincholic acid 28-O-beta-D-glucopyranosyl ester (2) were isolated from the roots of Adina pilulifera, together with 18 known compounds. The structures of 1 and 2 were determined by spectroscopic methods.

Glucotoxicity and lipotoxicity contribute to the impaired beta-cell function observed in type 2 diabetes. Here we examine the effect of saturated and monounsaturated fatty acids at different glucose concentrations on human beta-cell turnover and secretory function. Exposure of cultured human islets to saturated fatty acid and/or to an elevated glucose ...

We report a practical and scalable synthetic route for the preparation of alpha-substituted beta-amino acids (beta(2)-amino acids). Michael addition of a chiral hydroxylamine, derived from alpha-methylbenzylamine, to an alpha-alkylacrylate followed by cyclization gives a diastereomeric mixture of alpha-substituted isoxazolidinones. These diastereomers are separable by column chromatography. Subsequent hydrogenation of the ...

A thermostable N-carbamoyl- l-amino acid amidohydrolase ( l-N-carbamoylase) gene composed of an 1,230-bp ORF encoding a 44.3-kDa protein was cloned from the thermophile Bacillus kaustophilus CCRC11223. This l-N-carbamoylase contained six cysteine residues that form three disulfide bridges. The purified l-N-carbamoylase was stringently l-specific and exhibited high activity in the hydrolysis ...

A series of novel beta-amino acids has been synthesized and tested for their in vitro antifungal activity against Candida albicans. A steep SAR was observed. beta-Amino acid 21 (BAY 10-8888/PLD-118) revealed the most favourable activity-tolerability profile and was selected for clinical studies as a novel antifungal for the oral treatment ...

To investigate the mechanism of action of two antiplasmodial compounds, ellagic acid and 3,4,5-trimethoxyphenyl (6'-O-galloyl)-beta-D-glucopyranoside (TMPGG), we studied in vitro two metabolic reactions of intraerythrocytic parasites: the activity of recombinant plasmepsin II, one of the haemoglobin proteases, and the detoxification of haematin into beta-haematin. Both compounds inhibited plasmepsin II activity, ...

Infrared and Raman microspectroscopy have been used to follow the photodimerisation reactions of single crystals, the alpha- and beta-forms of trans-cinnamic acid. This approach allows the starting materials and products-alpha-truxillic acid that has Ci symmetry and beta-truxinic acid, which has Cs symmetry-to be identified. It also allows the topotactic nature ...

From the leaves of barley, Hordeum vulgare, one new flavone C-glucoside and three known flavone glucosides were isolated and characterized by (1)H and (13)C NMR and MALDI-TOF-MS. The novel flavone C-glucoside was isovitexin 7-O-beta-[6' "-O-(E)-p-coumaroyl]glucoside (6' "-coumaroylsaponarin), and the known compounds were isovitexin 7-O-beta-[6' "-O-(E)-feruloyl]glucoside, isoorientin 7-O-beta-[6' "-O-(E)-feruloyl]glucoside, and tricin ...

Acid beta-glucocerebrosidase (N-acylsphingosyl-1-O-beta-D-glucoside:glucohydrolase) is a lysosomal glycoprotein that catalyzes the hydrolysis of the glycolipid glucocerebroside to glucose and ceramide. Inadequate levels of this enzyme underly the pathophysiology of Gaucher's disease. Cerezyme (Genzyme Corporation, Cambridge, MA, USA) is a partially deglycosylated form of recombinant human acid beta-glucocerebrosidase that is used in ...

Recognition of five steroid compounds, beta-estradiol, ethynylestradiol, estradiolbenzoate, testosterone and methyltestosterone were studied using a synthesized molecularly imprinted polymer (MIP). When beta-estradiol was used as the template molecule, the polymer was synthesized with methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linking agent ...

A reinvestigation of the equilibria of (S)-alpha-alaninehydroxamic acid (alpha-Alaha) and (R)-aspartic-beta-hydroxamic acid (Asp-beta-ha) with copper(II) was performed in aqueous solution in order to clarify some contradictory literature reports regarding the stoichiometry of the polynuclear complexes formed. beta-Alaninehydroxamic acid (beta-Alaha, HL), for which the formation of a planar 12-metallacrown-4, [Cu(5)L(4)H(-4)](2+), was ...

Acidity constants of six substituted 1-benzyl-1-methoxy-2-nitroethylenes (2-Z with Z = m-NO(2), m-CF(3), m-Cl, H, p-Me, p-MeO) and their respective nitronic acids were determined in 50% DMSO-50% water (v/v) at 20 degrees C. Kinetic data were obtained on the reversible deprotonation of all six 2-Z by OH(-) and piperidine and on ...

The amino acid beta-alanine is an intermediate in pantothenic acid (vitamin B(5)) and coenzyme A (CoA) biosynthesis. In contrast to bacteria, yeast derive the beta-alanine required for pantothenic acid production via polyamine metabolism, mediated by the four SPE genes and by the FAD-dependent amine oxidase encoded by FMS1. Because amine ...

The influence of adipate concentration and dissolved oxygen on production of adipoyl-7-aminodeacetoxycephalosporanic acid (ad-7-ADCA) by a recombinant strain of Penicillium chrysogenum expressing the expandase gene from Streptomyces clavuligerus was studied in glucose-limited continuous cultures. Operating conditions were maintained constant but the adipate and dissolved oxygen concentrations (DOC) were varied separately ...

(+/-)-alpha-Hydrastine and (+/-)-beta-hydrastine were isolated from Corydalis longipes; both exhibited considerable efficacy against spore germination of some saprophytic and phytopathogenic fungi. While (+/-)-alpha-hydrastine was effective against most of the fungi, Helminthosporium echinoclova was least affected even at the highest dose (150 ppm). (+/-)-beta-Hydrastine was equally effective against several fungi. Mixture ...

We investigated the effects of an angiotensin-converting enzyme inhibitor (temocapril) and an angiotensin II type 1 receptor blocker (olmesartan) on changes in myocardial sympathetic nervous activity, fatty acid metabolism and myocardial blood flow using 131I-meta-iodobenzylguanidine, 125I-beta-methyl-iodophenyl pentadecanoic acid and 99mTc-tetrofosmin, respectively, in rats with isoproterenol-induced cardiac hypertrophy. Male Sprague-Dawley rats ...

Assay-guided fractionation of the ethanol extract of the twigs and leaves of Miconia trailii yielded two new flavanone glycosides, matteucinol 7-O-alpha-l-arabinopyranosyl(1-->6)-beta-d-glucopyranoside (miconioside A, 1) and farrerol 7-O-beta-d-apiofuranosyl(1-->6)-beta-d-glucopyranoside (miconioside B, 2), along with the known compounds matteucinol 7-O-beta-d-apiofuranosyl(1-->6)-beta-d-glucopyranoside (3), matteucinol (4), 2alpha,3beta,19alpha-trihydroxyolean-12-ene-24,28-dioic acid (bartogenic acid, 5), 2alpha,3beta,23-trihydroxyolean-12-ene-28-oic acid (arjunolic acid, 6), ...

Beta(3)-adrenoceptor is the predominant beta-adrenoceptor in adipocytes and has drawn much attention during the investigation for anti-obesity and antidiabetes therapeutics. Thirteen new compounds have been evaluated for their potencies and efficacies as beta(3)-adrenoceptor agonists on human beta(3)-adrenoceptor expressed in COS-7 and Chinese hamster ovary (CHO) cells using radioligand binding assay ...

New and very easily accessible monodentate phosphoramidite ligands have been developed that lead to excellent ee's and full conversions in the hydrogenation of (E)- and (Z)-beta-dehydroamino acid derivatives with both aliphatic and aromatic side chains. Particularly, two different catalytic systems were established for (E)-beta-(acylamino)acrylates (98-99% ee) and (Z)-beta-(acylamino)acrylates (92-95% ee) ...

A phytochemical study on the ethanol extract of the aerial parts of Schnabelia tetradonta led to the isolation of five new compounds, 1-5, together with seven known compounds. The structures of the new compounds were elucidated on the basis of spectral data interpretation as 2alpha,3alpha,23,29-tetrahydroxyolean-12-en-28-oic acid (1), 3-O-beta-d-glucuronopyranosyl-2beta,3beta,16beta-trihydroxy-28-norolean-12-en-15-on-23-oic acid (2), ...

beta,beta-Carotene 15,15'-monooxygenase (formerly termed beta,beta-carotene 15,15'-dioxygenase, EC 1.13.11.21) catalyzes the conversion of provitamin A carotenoids to retinal in vertebrate tissues. In the present study, we investigated whether preformed vitamin A or beta-carotene and its direct metabolites can regulate the enzyme activity in vivo. We found dose-dependent decreases in intestinal beta,beta-carotene ...

The crystal structure of the inclusion complex of beta-cyclo-dextrin with mefenamic acid has been determined from a combination of high-resolution synchrotron powder-diffraction data and molecular-mechanics calculations. A grid search indicates two possible solutions, which are corroborated by molecular-mechanics calculations, while Rietveld-refinement results suggest the crystal structure that is more likely ...

Bacillus amyloliquefaciens strain RC-2 produced seven antifungal compounds (1-7) secreted into the culture filtrate. These compounds inhibited the development of mulberry anthracnose caused by the fungus, Colletotrichum dematium. Chemical structural analyses by NMR and FAB-MS revealed that all these compounds were iturins (cyclic peptides with the following sequence: L-Asn --> ...

Humic acids are large, complex, organic molecules which are ubiquitous components of aquatic environments as products of degradation of plant material. In aqueous solution they form microvesicles. As many teleost pheromones are steroidal in nature, we hypothesised that they would preferentially dissolve in the organic, hydrophobic core of these vesicles ...

Sugar Amino Acids (SAAs) are sugar moieties containing at least one amino and one carboxyl group. The straightforward synthesis of two furanoid SAAs, 3-amino-3-deoxy-1,2-isopropylidene-alpha-D-ribofuranoic acid (f-SAA1) and 3-amino-3-deoxy-1,2-isopropylidene-alpha-D-allofuranoic acid (f-SAA2) starting from diacetone glucose, is described. These SAAs were used as structural templates aiming at new structures for peptidomimetic drug ...

FT-IR spectroscopy was applied to investigate 15 different carotenoids. The following compounds were examined: beta-carotenone (1); semi-beta-carotenon-epoxide (2); beta-apo-8'-carotenal (3); ethyl-beta-apo-8'-carotenoate (4); beta-citraurin (5); 5,6-Epoxy-beta-caroten-8'-al (6); beta-citraurin-epoxide (7); apo-10'-violaxanthal (8); persicaxanthin (9); capsylaldehyde (10); capsanthylal (11); retinol (12); retinal (13); retinoic acid (14); and bixin (15). Some characteristic functional groups ...

A new alkaloid, 1,2,3,9-tetrahydropyrrolo(2,1-b)quinazolin-1-carboxylic acid (1), together with eight known compounds, 7-hydroxy vasicine (2), benzyl alcohol beta-D-(2'-O-beta-xylopyranosyl)glucopyranoside (3), benzyl alcohol O-beta-D-glucopyranoside (4), benzyl alcohol O-beta-D-primveroside (5), 3,5-dimethyl-4-hydroxy benzaldehyde (6), gluco-syringic acid (7), syringin (8), and liriodendrin (9), were isolated from the plants of Linaria vulgaris. Their structures were established by ...

Clavulanic acid is only a modestly effective antibiotic against bacterial infections in humans, but a potent inhibitor/inactivator of beta-lactamase enzymes that confer bacterial resistance. The biosynthetic pathway to clavulanic acid is considerably more complex than that to the structurally related penicillins and cephalosporins and has revealed several interesting reactions.

From the bark of Mitragyna inermis, two 27-nor-triterpenoid glycosides, named inermiside I (1) and II (2), were isolated and their structures determined based on extensive 2D-NMR and MS spectral analysis as 6-deoxy-beta-D-glucopyranosyl-[3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]-pyrocincholate and 6-deoxy-beta-D-glucopyranosyl-pyrocincholate, respectively. In addition, the known quinovic acid (6), 3-O-[beta-D-glucopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl]-quinovoic acid (3),beta-D-glucopyranosyl-[3-O-(beta-D-glucopyranosyl)]-quinoviate (4) and cytotoxic 3-O-(beta-D-6-deoxy-glucopyranosyl)-quinovic acid ...

The first synthesis of (alphaS,betaS)-beta-hydroxy-alpha-[(methoxycarbonyl)amino]-4,6-dimethyl-9-oxo-3-beta-D-ribofuranosyl-4,9-dihydro-3H-imidazo[1,2-a]purine-7-butanoic acid methyl ester [(alphaS,betaS)-11] has been achieved by OsO(4) oxidation of [S-(E)]-4-[4,6-dimethyl-9-oxo-3-[2,3,5-tris-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]-4,9-dihydro-3H-imidazo[1,2-a]purin-7-yl]-2-[(methoxycarbonyl)amino]-3-butenoic acid methyl ester (13) followed by successive gamma-deoxygenation through the cyclocarbonates, separation from the (alphaS,betaR)-isomer by means of flash chromatography, and deprotection. On the other hand, the minor nucleoside of rat liver tRNA(Phe) ...

L-Asparaginase is known to catalyze the hydrolysis of L-asparagine to L-aspartic and ammonia, but little is known about its action on peptides. When we incubated L-asparaginases purified either from Escherichia coli or Erwinia chrysanthemi - commonly used as chemotherapeutic agents because of their antitumour activity - with eight small beta-aspartylpeptides ...

Magnaporthe grisea is a fungal pathogen that infects rice leaves and causes rice blast, a devastating crop disease. M. grisea produces active elicitors of the hypersensitive response in rice that were previously identified as ceramide monohexosides (CMHs). Using several chromatographic approaches, mass spectrometry, and nuclear magnetic resonance, we identified ceramide ...