A novel size exclusion phenomenon between PS-BEMP and sterically bulky BPAs, has been discovered and exploited in a one-pot base-catalysed Michael addition/acid-catalysed enantioselective N-acyliminium cyclisation cascade, allowing the preparation of structurally complex β-carbolines with moderate to good enantiocontrol.

A short, concise synthesis of enantiopure, side chain-modified a-amino acids such as 4-oxo-L-norvaline, 6-oxo-L-homonorleucine, 5-cis-alkyl prolines is described. Knoevenagel condensation of L-aminocarboxylate-derived b-ketoesters with aldehydes followed by reductive decarboxylation results unnatural a-amino acids in good yield. A fluorescent amino acid is synthesized using a similar protocol. These studies show that ...

Several serine hydrolases catalyze a promiscuous reaction: perhydrolysis of carboxylic acids to form peroxycarboxylic acids. The working hypothesis is that perhydrolases are more selective than esterases for hydrogen peroxide over water. In this study, we tested this hypothesis, and focused on L29P-PFE (Pseudomonas fluorescens esterase), which catalyzes perhydrolysis of acetic ...

A highly efficient rhodium-catalyzed protocol for the preparation of 2-arylsuccinic esters and 3-arylpyrrolidines of high optical purity has been achieved. In the presence of 1 mol % of a chiral diene/Rh(I) catalyst, asymmetric addition of various arylboronic acids to di-tert-butyl fumarate (3c) provides the corresponding adducts in up to 99% ...

Long chain l-2-hydroxy acid oxidase 2 (Hao2) is a peroxisomal enzyme expressed in the kidney and the liver. Hao2 was identified as a candidate gene for blood pressure (BP) quantitative trait locus (QTL) but the identity of its physiological substrate and its role in vivo remains largely unknown. To define ...

We present a fast and accurate method for preparation of fatty acid methyl esters (FAMEs) using microwave-assisted derivatization of fatty acids present in yeast samples. The esterification of free/bound fatty acids to FAMEs was completed within 5 min, which is 24 times faster than with conventional heating methods. The developed method ...

Synthesis of triazole based unnatural amino acids and β-amino triazoles has been described via a stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope and has significant potential for the synthesis of unnatural amino ...

Industrial nitriles from biomass: Vanadium-chloroperoxidase is successfully used to transform selectively glutamic acid into 3-cyanopropanoic acid, a key intermediate for the synthesis of bio-succinonitrile and bio-acrylonitrile, by using a catalytic amount of a halide salt. This clean oxidative decarboxylation can be applied to mixtures of amino acids obtained from plant ...

Multivariate analysis of (1)H NMR data has been used for the characterization of 12 blended olive oils commercially available in the U.S. as Italian products. Chemometric methods such as unsupervised Principal Component Analysis (PCA) allowed good discrimination and gave some affinity indications for the U.S. market olive oils compared to ...

Motility plays a major role in pathogenicity of Helicobacter pylori, yet there is scarce data regarding its chemotactic behaviour. The present study was designed to investigate the chemotactic responses of local isolates of H. pylori towards various sugars, amino acids, as well as some other chemical substances. Chemotaxis was assayed ...

Use of cheap, nontoxic, and selective solvents could economically provide a solution to the recovery of carboxylic acids produced by the bioroute. In this regard in the present paper, reactive extraction of citric acid was studied. Problems encompassing the recovery of the acid ([H(3)A] (aq) (o)  = 0.1-0.8) was solved by ...

Divalproex sodium is an antiepileptic drug. Hepatotoxicity is one of the most common side effects induced by divalproex sodium. Impaired fatty acid metabolism is considered to play an important role in the drug-induced hepatotoxicity. The sterol regulatory element-binding protein 1c (SREBP-1c) and peroxisome proliferator-activated receptor α (PPARα) are two key ...

A convenient route to isoindolo[2,1-a]indol-6-ones has been developed starting from the appropriate 2-(N-phthaloyl)benzoic acids. Formation of the acid chlorides with thionyl chloride followed by heating with triethyl phosphite in a suitable solvent resulted in a multistep reaction giving tetracyclic β-ketophosphonates that on reduction with sodium borohydride gave the required indolones ...

New cholic acid based calix[4]pyrroles and porphyrins were prepared and their properties were studied. It was confirmed by spectral measurements that the superassembly of 5,15-bis(3α,7α,12α-trihydroxy-5β-cholan-24-yl)-10,20-diphenylporphyrin, the best candidate for this study from the conjugates prepared, may be influenced not only by the solvent mixture composition (polar/non-polar component ratio) but by ...

A new 7-nitrobenz-2-oxa-1,3-diazole (NBD)-based fluorescent chiral chemosensor (NBD-1) was prepared and applied to the recognition of the two enantiomers of the tetrabutylammonium salts of N-t-Boc-α-amino acids and chiral carboxylic acids including naproxen. In particular, the chiral recognition by the new fluorescent chiral chemosensor for the two enantiomers of N-t-Boc-threonine (tetrabutylammonium ...

The objective was to examine the effect of the additives acetic acid, lactic acid, sodium bicarbonate, sodium chloride, and sodium hydroxide on the hydrolysis of whey protein isolate with subcritical water. A screening experimental design was used to study the effect of temperature, time, and additives. The most influential additive, ...

Syntheses of four castor oil fatty acid-based novel lipoconjugates of phenolic acids were carried out following Mitsunobu methodology. The lipid part consists of methyl ricinoleate and its saturated analogue, methyl-12-hydroxystearate and the phenolic moieties are ferulic and vanillic acid. Synthesised compounds are evaluated for antioxidant activity using three in vitro ...

O-benzyl-L-serine carboxyanhydrides were synthesized via diazotization of O-benzyl-L-serine with sodium nitrite in aqueous sulfuric acid solution followed by cyclization of the resulting serine-based α-hydroxy acid with phosgene. Degradable, water-soluble poly(α-hydroxy acids) bearing pendant hydroxyl groups were readily prepared under mild conditions via ring-opening polymerization of O-benzyl-L-serine carboxyanhydrides followed by removal ...

Microcontact chemistry has been applied to patterned glass and silicon substrates by successive reaction of unprotected and monoprotected heterobifunctional linkers with alkene-terminated self-assembled monolayers (SAMs) to produce bi-, tri-, and tetrafunctional surfaces. Photochemical microcontact printing of an azide thiol linker followed by immobilization of an acid thiol linker on an ...

Styrene is formed by the thermal decarboxylation of cinnamic acid during wort boiling or by enzymatic decarboxylation during fermentation. The enzymatic reactions proceed in parallel to the decarboxylation of ferulic- and p-cumaric acid to 4-vinylguaiacol and 4-vinylphenol by the same decarboxylase enzyme. However, the formation of styrene occurs much faster ...

An Eu-based metallo-supramolecular polymer (polyEu) was prepared by self-assembly coordination polymerization. Unique vapoluminescence property of polyEu triggered by acid-base vapor was found and a photoluminescence display in switchable imaging by acid-base vapor was fabricated.

The purpose of this study was to demonstrate that the surface of CaCO(3) fillers could be coated with an N-halamine based fatty acid to make the filler surface organophilic and accomplish antibacterial activity simultaneously, rendering the resulting polymer-filler composites antimicrobial. Thus, a new bi-functional compound, 4, 4 -Dimethyl hydantoin-undecanoic acid ...

Nitrones and tert-butanesulfinyl imines undergo conjugate addition to alkyl allenoates under SmI(2)-mediated reductive coupling conditions to produce novel β-methylenyl-substituted γ-amino esters. The latter were readily transformed into the corresponding β-methylenyl-γ-lactams by simple zinc reduction (N-hydroxy amines) or by acid hydrolysis (sulfinamides). The diastereoselective preparation of various β-methylenyl-γ-lactams offers a route ...

Viruses play an important role in acute otitis media (AOM) pathogenesis, and live viruses may cause AOM in the absence of pathogenic bacteria. Detection of AOM pathogens generally relies on bacterial culture of middle ear fluid. When viral culture is used and live viruses are detected in the middle ear ...

Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant ...

Eggplant (Solanum melongena) is a very rich source of polyphenol oxidase (PPO), which negatively affects its quality upon cutting and postharvest processing due to enzymatic browning. PPO inhibitors, from natural or synthetic sources, are used to tackle this problem. One isoform of PPO was 259-fold purified using standard chromatographic procedures. ...

Chiral conducting polymers prepared by electropolymerising PEDOT in the presence of chiral anions such as hyaluronic acid and anionic collagen or in a chiral nematic phase (hydroxypropyl cellulose, HPC) show excellent chiral acid recognition. This paper demonstrates the enantioselective recognition and transfer of protonated mandelic acid and protons using chiral ...

By designing a long and hydrophobic stilbeneboronic acid (STDBA) and allowing it to be included within the cavity of γ-cyclodextrin (γ-CyD) we succeeded in developing a fluorescent 2 : 2 STDBA-γ-CyD ensemble that shows a selective and sensitive response toward glucose in aqueous solutions, with satisfactory application in artificial urine samples.

A novel method for the preparation of N-acylpyrrole is described. The method involves condensation of carboxylic acids with 2,4,4-trimethoxybutan-1-amine, followed by acid-mediated cyclization to form the pyrrole ring. The preparative procedure is highly tolerant of a variety of functional groups.

The α- and β-d-glucoseptanose pentaacetates have been prepared by treatment of ethyl 1-thio-β-d-glucoseptanoside tetraacetate with mercury(II) acetate in acetic acid. The solid state structure of the β-isomer has been determined by X-ray diffraction.

A novel silica-based reversed-phase/strong anion-exchange mixed-mode stationary phase named C18SAX was synthesized based on the polar-copolymerized approach. C18SAX stationary phase showed excellent compatibility with 100% aqueous mobile phase and comparable performance with commercial SunFire™ C18 column in terms of column efficiency and methylene selectivity. And the results indicated that hydrophobic ...

Current affairs: Adiponitrile, used to produce nylon 6.6, is prepared from the renewable compound glutamic acid by an electrochemical route, involving electro-oxidative decarboxylation and Kolbe coupling reactions. The new route is an example of the use of glutamic acid as a versatile substrate in the transformation of biomass into chemicals. Also, ...

Built in for clicks: A specially evolved pyrrolysyl-tRNA synthetase from Methanosarcina mazei was used to incorporate a norbornene amino acid into proteins in E. coli. This unit can be site-selectively modified under mild physiological conditions using a [3+2] cycloaddition reaction with nitrile imines.

The silylated derivatives of a layered alkali silicate, magadiite, modified with propylsulfonic or arylsulfonic acid were synthesized and used as catalysts for a acid-catalyzed condensation of phenol with acetone. The propylsulfonated magadiites with the different amount of the attached silyl group was synthesized by the silylation of the dodecylammonium-exchanged magadiite ...

A practical, mild and highly selective protocol for the monodeuteration of a variety of arenes and heteroarenes is presented. Catalytic amounts of Ag(i) salts in DMSO/D(2)O are shown to facilitate the deutero-decarboxylation of ortho-substituted benzoic and heteroaromatic α-carboxylic acids in high yields with excellent levels of deuterium incorporation.

In the milk of marsupials, oligosaccharides usually predominate over lactose during early to mid lactation. Studies have shown that tammar wallaby milk contains a major series of neutral galactosyllactose oligosaccharides ranging in size from tri- to at least octasaccharides, as well as β(1-6) linked N-acetylglucosamine-containing oligosaccharides as a minor series. ...

3-Methyl-1-sulfonic acid imidazolium nitrate ([Msim]NO3) as a new Brønsted acidic ionic liquid and nitrating agent was prepared, and used for the efficient nitration of aromatic compounds (even aniline derivatives). The dramatically effect of this reagent by in situ formation of nitrogen dioxide as a radical, on aromatic compounds to give ...

Volatile compounds in the peel of calamansi (Citrus microcarpa) from Malaysia, the Philippines and Vietnam were extracted with dichloromethane and hexane, and then analysed by gas chromatography-mass spectroscopy/flame ionisation detector. Seventy-nine compounds representing >98% of the volatiles were identified. Across the three geographical sources, a relatively small proportion of potent ...

The apical sodium dependent bile acid transporter (ASBT) and sodium-taurocholate cotransporting polypeptide (NTCP) are potential prodrug targets, but the structural requirements for these transporters are incompletely defined. The objective of this study was to evaluate the effect of C-3 and C-7 substitution on bile acid interaction with these bile acid ...

This study investigated the effect of salt reduction and partial replacement with KCl on the microbiological and sensory characteristics of fresh and matured Halloumi cheese. Halloumi samples were matured for 8 wk and moisture, fat, protein, pH, lactic acid, sodium, and potassium contents determined. Instrumental textural characteristics of the samples ...

A modified chemical-precipitation method is proposed to synthesize MgO nanopowders with high crystallinity at a low temperature of 400 degrees C using acetic acid as a modifier. The as-obtained intermediates and final products were investigated by Fourier-transformed infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and transmission electron microscopy, respectively. The influence ...

To evaluate the alteration of chemical behavior of L-ascorbic acid (vitamin C) with metal ion (nickel) at different pH solutions in vitro. Spectra of pure aqueous solution of L-ascorbic acid (E mark) compound and NiSO4 (H2O) (sigma USA) were evaluated by UV visible spectrophotometer. Spectral analysis of L-ascorbic acid and ...

A biodegradable nanocarrier system based on PLGA applicable for FR targeting is described. PEI-based conjugates with covalently coupled folic acid are synthesized, characterized with regard to their composition and used for DNA complexation. The preparation of composites is performed by a solvent displacement technique, assuming an electrostatic interaction of PEI-based ...

The objective of this study was to understand the prolonged analgesic action of morphine hydrochloride observed in the presence of sodium 12-oxochenodeoxycholanate. Based on literature, this phenomenon may be due to the formation of aggregates in the cell between the molecules of bile acids and morphine. In addition to the ...

G-quadruplex (G4) is a characteristic secondary structure of nucleic acids containing repetitive tandem guanines. G4-forming sequences are found prevalent in the human genome by bioinformatics analysis. Accumulating evidence has suggested that G4s are involved in many biological processes. Selective isolation of G4s would be an effective tool in the study ...

A denuder/filter apparatus was used to collect the gaseous and particulate reaction products from ozonlysis of α-pinene, limonene and α-terpineol in an effort to develop sampling techniques for characterizing indoor environment chemistry. Carboxylic acids found in the particulate phase were derivatized to 2,2,2-trifuoroethylamides by reaction with 3-ethyl-1-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC) and ...

Amidase-catalyzed desymmetrization of meso-N-heterocyclic dicarboxamides under very mild conditions provided a highly efficient and practical method for the preparation of enantiomerically pure carbamoyl-substituted heterocyclic amino acids that were unique and versatile platforms for the construction of both antipodes of aza-sugar containing nucleoside analogs.

OBJECTIVES: The aim of the study was to determine in situ the relative abilities of two desensitising toothpastes to occlude dentinal tubules with or without acid challenge. MATERIALS AND METHODS: The study design was a single centre, randomised, split mouth crossover model examining four treatments over two periods. The primary ...

Structured phenolic lipids (PLs) were obtained by lipase-catalyzed transesterification of flaxseed oil, in a solvent-free system (SFS), with selected phenolic acids, including hydroxylated and/or methoxylated derivatives of cinnamic, phenyl acetic and benzoic acids. A bioconversion yield of 65% was obtained for the transesterification of flaxseed oil with 3,4-dihydroxyphenyl acetic acid ...

We have reported that lactobionic acid is produced from lactose by Acetobacter orientalis in traditional Caucasian fermented milk. To maximize the application of lactobionic acid, we investigated favorable conditions for the preparation of resting A. orientalis cells and lactose oxidation. The resting cells, prepared under the most favorable conditions, effectively ...