A general method to synthesize functionalized azabicyclo[X.3.0]alkane scaffolds 5 is reported. Key intermediates are azabicycloalkenes such as 1 and 2, which are acylated with unsaturated carboxylic acids and subsequently submitted to tandem olefin metathesis. The resulting bicyclic heterocycles are versatile intermediates for different dipeptide mimetics and can be used as ...

Despite the wide utility of ferrite nanoparticles (FP), a methodology to conjugate heterologous molecules to FP is still limited and characterization of small molecule-conjugated FP is not well known. Here, we describe what kinds of proteins and amino acids are selectively immobilized onto FP when FP is synthesized in the ...

Configurational-bias Monte Carlo simulations were carried out in the Gibbs ensemble to generate phase equilibrium data for several carboxylic acids. Pure component coexistence densities and saturated vapor pressures were determined for acetic acid, propanoic acid, 2-methylpropanoic acid, and pentanoic acid, and binary vapor-liquid equilibrium (VLE) data for the propanoic acid ...

High-affinity nitrilotriacetic acids (NTA) have great potential in the molecular manipulation of His-tagged proteins. We have developed a facile method to synthesize multivalent NTA and its conjugates. Starting with appropriately protected lysine, we synthesized the mono-NTA synthons functionalized with either an amino group or a carboxylic group. We then obtained ...

We have previously demonstrated that the reductive carboxylation of 2-oxoglutarate in Hydrogenobacter thermophilus TK-6 is not simply a reversal of the oxidative decarboxylation catalysed by isocitrate dehydrogenase (ICDH). The reaction involves a novel biotin protein (carboxylating factor for ICDH-CFI) and ATP. In this study, we have analysed the ICDH/CFI system ...

A keratin sponge was chemically modified to obtain carboxyl and amino sponges by the alkylation of a large amount of active SH group on keratin proteins with iodoacetic acid and 2-bromoethylamine, respectively. The carboxyl sponge having a large amount of carboxyl group was a scaffold that could bind significant amounts ...

A sensitive and efficient method using high-performance CE (HPCE) and neuraminidase hydrolysis was developed to study the lactonization and hydrolysis of alpha2,8-pentasialic acid. Eleven lactone species of pentasialic acid formed in glacial acetic acid were detected and classified into three groups based on the number of carboxylic acids: monolactones with ...

A series of one-stage oxygen delignification treatments with a softwood (SW) kraft pulp were studied employing 0.0-0.5% of a bismuth ruthenium pyrochlore oxide catalyst. The results demonstrated that a 0.09-0.18% charge of catalyst in an oxygen stage provided a 52.2-116.0% increase of carboxylic acid groups in the cellulosic component of ...

A practical UV-vis sensing method for enantioselective microanalysis of unprotected amino acids, amines, amino alcohols, and carboxylic acids in aqueous solution has been developed. Both concentration and enantiomeric composition of a wide range of chiral substrates can be determined with high accuracy by two simple competitive binding assays using a ...

The putative substrate-binding site in lipoxygenases is long and internal. There is little direct evidence about how the unsaturated fatty acid substrates enter and move within the cavity to position themselves correctly for electron transfer reactions with the catalytic non-heme iron. An EPR spectroscopy approach, with spin-labeled fatty acids, is ...

Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., ...

Fe(0) was investigated as a cost-effective, environmentally friendly alternative to Cr(II) for the olefination of carbonyls by activated polyhalides. In many instances, Fe(0) was equivalent or superior to Cr(II). Notably, Fe(0), but not Cr(II), proved compatible with a wide range of functionality, inter alia, unprotected phenol, aryl nitro, carboxylic acid, ...

The self-assemblies of di-acids HOOC-(CH(2))(n)-COOH (n = 20, 18, 16, 14, 12, 10) in three solvents hexanoic acid, octanoic acid, and decanoic acid on highly oriented pyrolytic graphite (HOPG) were studied with scanning tunneling microscopy (STM). In the solvent hexanoic acid, solvent molecules coadsorb with HOOC-(CH(2))(n)-COOH (n = 20, 18, ...

Fulvic acids are one of the largest classes of dissolved organic matter, but they are poorly defined and of unclear origin. Three fulvic acid isolates of different origin were analyzed by size-exclusion chromatography coupled to electrospray ionization-Fourier-transform ion cyclotron resonance (FTICR)-mass spectrometry, and molecular formulas for 700-1900 species in these ...

The electrocarboxylation of benzyl halides to the corresponding carboxylic acids through homogeneous charge-transfer catalysis was investigated both theoretically and experimentally to determine the influence of the operative parameters on the yield of the process and on the catalyst consumption. Theoretical considerations, based on fast kinetics of redox catalysis, were confirmed ...

The total synthesis of apoptolidin A is described employing an early glycosylation strategy. Strategic disconnections were chosen between C11-C12 (cross-coupling) and C19O-C1 (macrocyclization). The cis-selective glycosylation at C9-OH was achieved with the new SIBA protective group at O2/O3 of the L-glucose residue. Auxiliary substitutents at the 2-position of the 2-deoxy ...

Two different phosphonic acid monolayer films for immobilization of bioactive molecules such as the protein BMP-2 on titanium surfaces have been prepared. Monolayers of (11-hydroxyundecyl)phosphonic acid and (12-carboxydodecyl)phosphonic acid molecules were produced by a simple dipping process (the T-BAG method). The terminal functional groups on these monolayers were activated (carbonyldiimidazole ...

The formation of short-chain carboxylic acids was studied in Maillard model systems (90 degrees C, pH 6-10) with emphasis on the role of oxygen and water. The total amount of acetic acid formed did not depend on the reaction atmosphere. In the presence of labeled dioxygen or water (18O2, H2 ...

Aryl-substituted five-membered heteroaromatics have attracted great interest over the past years due to their presence in a large number of pharmaceuticals and natural products. Recently, an advance in the preparation of these scaffolds was achieved by employing a C-H functionalization strategy. This method allows easy access to these biaryl motifs ...

We designed self-etching primers consisting of a series of four N-methacryloyl-omega-amino acids, MomegaA, of different methylene chain numbers for resin core construction. The interacted amount of MomegaA's carboxylic acid with root or crown dentin apatite was determined, and its effects on dentin bond durability examined. The addition of both dentin ...

Recent studies of cellulose-based polymers substituted with carboxylic acids like cellulose acetate phthalate (CAP) have demonstrated the utility of using carboxylic acid groups instead of the more common sulfate or sulfonate moieties. However, the pK(a) of the free carboxylic acid group is very important and needs careful selection. In a ...

Carboxylic acids are known for their strong intermolecular associations. With chiral carboxylic acids, this behavior can be studied using vibrational circular dichroism (VCD). Tetrahydrofuran-2-carboxylic acid 1, a chiral building block for beta-lactam antibiotics, is studied by emphasizing the effect of the dimerization. Experimental results indicate that for solutions of 1 ...

We have achieved a total synthesis of telomestatin, and its absolute configuration was determined to be (R). Coupling of cysteine-containing trisoxazole amine and serine-containing trisoxazole carboxylic acid, followed by macrocyclization, provided a 24-membered diamide. The seventh oxazole ring was formed by a Shin's procedure via dehydroamide. Cyclodehydration of a modified ...

Previous studies have revealed the fractionation processes of rare earth elements (REEs) in hydroponic plants, with a heavy REE (HREE, the elements from Gd to Lu) enrichment in leaves. In this study, effects on the HREE enrichment in soybean leaves with additions of carboxylic acids (acetate, malate, citrate, NTA, EDTA ...

The chain and radial functional group distributions in carboxylic acid-functionalized poly(N-isopropylacrylamide)-based microgels have significant impacts on the types of swelling responses exhibited by the microgels upon the application of a temperature and/or pH stimulus. Potentiometric, conductometric, and calorimetric titration approaches are used in this work to characterize the chain distributions ...

IR spectroscopy of probe molecules (pyridine, 2,6-dimethylpyridine, and CO) as well as high-resolution solid state NMR and especially double-resonance experiments give a new insight into the acidic sites of amorphous silica alumina (ASA). ASA samples are heterogeneous compounds that contain a silica alumina mixed phase as well as aluminum clusters ...

[reaction: see text] (+/-)-Mitorubrinic acid, a member of the azaphilone family of natural products, has been constructed in 12 steps. Key aspects of the synthesis include elaboration and oxidative dearomatization of an isocoumarin intermediate to provide the azaphilone nucleus with a disubstituted, unsaturated carboxylic acid side chain.

The photoassisted mineralization, i.e., conversion to CO2 and water, of malonic acid over P25 TiO2 was investigated by in situ attenuated total reflection infrared (ATR-IR) spectroscopy in a small volume flow-through cell. Reassignment of the vibrational bands of adsorbed malonic acid, assisted by deuterium labeling, reveals two dissimilar carboxylate groups ...

4-{[2-[(2-Furylsulfonyl)(isobutyl)amino]-5-(trifluoromethyl)phenoxy]methyl}benzoic acid analogs 2a and b and a series of the acid analogs, in which the carboxylic acid residue of 2b was replaced with various kinds of carboxylic acid bioisosteres, were synthesized and evaluated as EP1 receptor antagonists. Compound 2b and its monocyclic acid analogs, in which the carboxylic acid ...

In this paper, we report the reactivity of fluoro-N,N,N',N'-tetramethylformamidinium hexafluorophosphate (TFFH), a reagent for transformation of carboxylic acids into acid fluorides in solution, toward self-assembled monolayers (SAMs) of 16-mercaptohexadecanoic acid on gold. Contrary to the solution-based reactions, we found that only interchain carboxylic anhydrides (ICAs), not acid fluorides (AFs), were ...

Population density, temperature and food availability all regulate the formation of the Caenorhabditis elegans dauer larva by modulating endocrine signaling pathways. The orphan nuclear receptor DAF-12 is pivotal for the decision to form a dauer or to undergo normal reproductive development. The DAF-12 ligand has been predicted to be a ...

The electrospray mass spectrometric characterization of neutral dendrons with a carboxylic acid function or a t-butyl ester moiety at the central point and up to eight peripheral C60 subunits has been performed and is described in detail. Molecules bearing a carboxylic acid group at the center turned out to be ...

The adsorption of glycine (NH2CH2COOH) was examined by scanning tunneling microscopy (STM) on TiO2(110) surfaces at room temperature. A (2x1) ordered overlayer was observed on the TiO2(110)-(1x1) surface. The adsorption of acetic acid and propanoic acid was also investigated on this surface and their STM images were quite similar to ...

The palladium acetate-catalyzed coupling reaction of aryl boronic acid with carboxylic anhydride or acyl chloride was carried out smoothly in water in the presence of poly(ethylene glycol) (PEG) or 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) to give high yields of ketones without the use of phosphine ligands. The Pd(OAc)2-H2O-[bmim][PF6] catalytic system can be ...

(3R,4R,5S)-4-Acetylamino-5-amino-3-hydroxy-cyclohex-1-ene-carboxylic acid ethyl ester, a functionalized cyclohexene skeleton of GS4104, was diastereoselectively synthesized. A major advantage of this synthesis is the use of readily available L-serine to replace frequently used (-)-shikimic acid or (-)-quinic acid as the starting material. Ring-closing metathesis and diastereoselective Grignard reactions successfully served as the key ...

A convenient two-step, one-pot procedure was developed for the conversion of primary alcohols to carboxylic acids. The alcohol was first treated with NaOCl and TEMPO under phase-transfer conditions, followed by NaClO2 oxidation in one pot. This reaction is applicable to a wide range of alcohols and the mild reaction conditions ...

We prepared molecularly imprinted polymers for an amnesic shellfish poison, domoic acid. To prepare the polymer, we tested several commercial aromatic dicarboxylic compounds such as isomers of phthalic acid for templates of molecularly imprinted polymers. The highest selective recognition ability of the polymer for domoic acid in the tested compounds ...

Fourier transform-infrared (FT-IR) spectroscopy has become an important tool for rapid analysis of complex biological samples. The infrared absorbance spectrum could be regarded as a "fingerprint" which is characteristic of biochemical substances. In this study, Pseudomonas putida NCIMB 9869 was grown with either 3,5-xylenol or m-cresol as the sole carbon ...

The acid-base properties of humic acids (HAs) and fulvic acids (FAs) isolated from liquid swine manure (LSM), soils amended with either 90 or 150 m(3)ha(-1)year(-1) of LSM for 7 years, and the corresponding unamended control soil were investigated by a current potentiometric titration method. The non-ideal competitive adsorption (NICA)-Donnan model ...

Acid-base dissociation constants (pK(a) values) are important in understanding the chemical, environmental and toxicological properties of molecules. Though various methods have been developed to predict pK(a) by experimental and theoretical models, prediction of pK(a) is still complicated. Hence, a new approach for predicting pK(a) using the group philicity concept has ...

4,4'-Bipyridine cocrystallizes with 3-hydroxy-2-naphthoic acid in a 1:2 ratio to give a centrosymmetric three-component supramolecular adduct, namely 3-hydroxy-2-naphthoic acid-4,4'-bipyridine (2/1), C11H8O3.0.5C10H8N2, in which 4,4'-bipyridine is located on an inversion center. The pyridine-carboxylic acid heterosynthon generates an infinite one-dimensional hydrogen-bonded chain via pi-pi interactions between naphthyl and 4,4'-bipyridine groups. The one-dimensional ...

Access to glycopeptides with C-terminal thioester functionality is essential for the synthesis of large glycopeptides and glycoproteins through the use of native chemical ligation. Toward that end, we have developed a concise method for the synthesis of a glycopeptide thioester having an intact complex-type dibranched disialyl-oligosaccharide. The synthesis employed a ...

(E/Z)-isomers containing vinyl bromides were stereoselectively carbonylated to the corresponding (E)-alpha,beta-ethylenic carboxylic acids in the ionic liquid [BMIM]PF6. Vinyl dibromides also underwent hydroxycarbonylation to give monoacids. The products are pure by proton NMR spectroscopic determination without purification by silica gel column chromatography or recrystallization.

[reaction: see text] Whereas ozonization of furan 3a affords little or no carboxylic acid 5, ozonization of the corresponding trans-enedione 6 afforded carboxylic acid 5 in 82.4% yield (cryst., overall from furan, 100 g scale; after workup with dimethyl sulfide, followed by mildly basic hydrogen peroxide). This new approach to ...

Glycidyl esters upon treatment with a mixture of carboxylic acid anhydride (CAA) and trimethylsilyl halide (TMSX) in the presence of tetra-n-butylammonium halide (Bu(4)NX, X=Cl, Br or I) undergo stereospecific and regioselective opening of the oxirane ring to afford mixed-(or mono)-acid 1,2(2,3)-diacyl-3(1)-halo-sn-glycerols in high yields.

[reaction: see text] C,D-ring symmetric chlorins 8 were prepared in 47-85% yield, on scales up to several hundred milligrams, by condensation of appropriately substituted bis-formyldihydrodipyrrins 6 and dipyrromethane bis-carboxylic acids 7 in 5% TFA/CH2Cl2 (25 examples). Target chlorins were chosen to systematically probe the effect of lipophilic and hydrophilic substituents ...

[reaction: see text] A very efficient method for the simultaneous protection of the amino group and activation of the carboxyl group of amino acids is reported using propargyl pentafluorophenyl carbonate (PocOPfp). The amino group is protected as a propargyloxycarbonyl (Poc) derivative, and the carboxyl group is activated as a pentafluorophenyl ...

Two bifunctional linkers, a rigid-rod p-ethynyl-isophthalic acid capped with a Ru(II)-polypyridyl complex and 3-mercaptopropionic acid, were covalently bound to ZnO nanotip films grown by metal-organic chemical vapor deposition (MOCVD) technology. This highly vertically aligned, crystalline form of ZnO had not been functionalized before. The binding was studied by Fourier transform ...

The acid unfolding of staphylococcal nuclease (SNase) is very cooperative (Whitten and García-Moreno, Biochemistry 2000;39:14292-14304). As many as seven hydrogen ions (H+) are bound preferentially by the acid-unfolded state relative to the native (N) state in the pH range 3.2-3.9. To investigate the mechanism of acid unfolding, structure-based pKa calculations ...

This review presents more than 260 naturally occurring (as well as 47 synthesized) neo fatty (carboxylic) acids, neo alkanes, and their analogs and derivatives, isolated and identified from plants, algae, fungi, marine invertebrates, and microorganisms, that demonstrate different biological activities. These natural metabolites are good prospects for future chemical preparations ...