In this article, we proved that all three key steps in the catalytic cycle of CuAAC can proceed in the presence of carboxylic acids and the latter two steps can be promoted significantly by carboxylic acids. Benzoic acid showed the best promotion activity, and the acids with strong chelating ability ...

Oxygen exchange may occur at carboxyl groups catalyzed by acid. The reaction, however, takes at least several days at room temperature. The long-time exchanging reaction often prevents its application from protein analysis. In this study, an (18)O-labeling method utilizing microwave-assisted acid hydrolysis was developed. After being dissolved in (16)O/(18)O (1:1) ...

Melia azedarach is a species gaining scientific interest mostly concerning its range of biological activities against agricultural target pests. The nematicidal melia methanol extract (MME) obtained from the fruits, acting against the phytonematode Meloidogyne incognita , is herein reported to contain hexadecanoic, acetic, and hexanoic acids as well as furfural, ...

Reaction of a heteroleptic cyclometalated iridium complex incorporating a carboxylic acid appended dipyrrin with copper acetate leads to the formation of a hexanuclear species with the paddlewheel structure.

Determination of the structure of heparin-derived oligosaccharides by (1)H NMR is challenging because resonances for all but the anomeric protons cover less than 2 ppm. By taking advantage of increased dispersion of resonances for the anomeric H(1) protons at low pD and the superior resolution of band-selective, homonuclear-decoupled (BASHD) two-dimensional (1)H ...

A variety of hetero(aromatic) carboxylic acids are shown to undergo decarboxylative homocoupling, mediated by a Pd/Ag system. This novel methodology for the synthesis of symmetrical biaryls avoids the use of haloarenes and organometallic compounds as starting materials.

Organically-modified hydroxyapatite materials were synthesized through the addition of oxalic, succinic, adipic and citric acids to a calcium hydroxide solution before neutralization by ammonium dihydrogenphosphate. All carboxylic acids have a significant influence on apatite crystallinity and nanoparticle size, as indicated by XRD and TEM. Chemical and thermogravimetric analyses as well ...

Raman spectroscopy has many advantages for planetary exploration, and the Raman technique is currently being developed for future space missions. The Raman microspectroscopic study of organic acids (phthalic and mellitic acids) in experimentally prepared mixtures with halite and gypsum was performed using near infrared 785 nm and visible 514 nm ...

The Pipecolic linker is a new highly versatile handle which immobilizes on solid support through a carboxylic acid function a wide range of amines, alcohols, and hydrazines. The anchoring step on pipecolic resin is very easy and efficient, and compounds are released with high purities upon acidic treatment. During this ...

A study of proton-transport rates and mechanisms under anhydrous conditions using a series of acid model compounds, analogous to comb-branch perfluorinated ionomers functionalized with phosphonic, phosphinic, sulfonic, and carboxylic acid protogenic groups, is reported. Model compounds are characterized with respect to proton conductivity, viscosity, proton, and anion (conjugate base) self-diffusion ...

Germanium (Ge) nanowires were produced in solution by supercritical fluid-liquid-solid (SFLS) growth and then functionalized with carboxylic acid groups by in situ thermal thiolation with mercaptoundecanoic acid. Polyethylene glycol (PEG) was grafted to the carboxylic acid-terminated Ge nanowires using carbodiimide coupling chemistry. The nanowires were characterized using attenuated total reflectance ...

A series of molecular complexes, both co-crystals and salts, of a triazole drug-alprazolam-with carboxylic acids, boric acid, boronic acids, and phenols have been analyzed with respect to heterosynthons present in the crystal structures. In all cases, the triazole ring behaves as an efficient hydrogen bond acceptor with the acidic coformers. ...

Nikkomycin Z is a dipeptide antifungal antibiotic characterized by two nonproteinogenic amino acids, nikkomycin C(Z) and 4-(4'-hydroxy-2'-pyridinyl)-homothreonine (HPHT). The HPHT scaffold is assembled by an aldol reaction between 2-oxobutyrate and picolinaldehyde, the latter of which is derived from picolinic acid that is activated and loaded to coenzyme A by the ...

The dissolution and pharmacokinetics (PK) of two carboxylic acid co-crystals (cinnamic acid and benzoic acid) with the corresponding amide co-crystals (cinnamamide and benzamide) of AMG 517 were investigated. Powder and intrinsic dissolution studies were performed in fasted simulated intestinal fluid (FaSIF). Suspension formulations in 1% polyvinylpyrrolidone K25 in water were ...

A variety of optically active carboxylic esters are produced by the kinetic resolution of racemic alpha-substituted carboxylic acids using achiral alcohols, aromatic or aliphatic carboxylic anhydrides, and chiral acyl-transfer catalysts. The combination of 4-methoxybenzoic anhydride (PMBA) or pivalic anhydride with the modified benzotetramisole-type catalyst ((S)-beta-Np-BTM) is the most effective for ...

The hexamer and octamer of trans-2-aminocyclobutane carboxylic acid were prepared and their conformational preferences studied experimentally and using molecular modeling. All observations suggest a marked preference for the folding of these oligomers into a well-defined 12-helical conformation, in both solution and the solid state.

A facile synthesis of 2H-3,1-benzothiazine-2,4(1H)-dithiones (trithioisatoic anhydrides) or 2H-naphtho[2,3-d][1,3]thiazine-2,4(1H)-dithione solely from anthranilic acids or 3-amino-2-naphthoic acid and carbon disulfide, performed at room temperature in 1,4-dioxane in the presence of Et(3)N, is reported. Corresponding 2-alkylsulfanyl derivatives were obtained in one-pot reactions under the same conditions after addition of alkyl halides. The ...

A direct, selective and highly efficient method has been developed for the hydrocarboxylation of C(n) gaseous alkanes into C(n+1) carboxylic acids, in aqueous acid-solvent-free medium at low temperatures. The approach is based on a metal-free or copper-promoted reaction of ethane, propane or n-butane with carbon monoxide and water, in a ...

We demonstrate that single wall carbon nanotubes (SWCNTs) can be coated by a layer of silica through the reaction between chlorosilane and acid-treated SWCNTs. The presence of carboxylic acid groups in the SWCNTs provides the active sites where chlorosilane can be anchored to form the silica coating. Silica nanotubes with ...

Cytochrome P450(BSβ), a H(2)O(2)-dependent cytochrome P450 catalyzing the hydroxylation of long-alkyl-chain fatty acids, lacks the general acid-base residue around the heme, which is indispensable for the efficient generation of the active species using H(2)O(2). On the basis of the crystal structure of the palmitic acid bound form of cytochrome P450(BSβ), ...

The UV-dissipative mechanisms of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and the 4,7-dideutero derivative (DHICA-d(2)) in buffered H(2)O or D(2)O have been characterized by using ultrafast time-resolved fluorescence spectroscopy. Excitation of the carboxylate anion form, the dominating state at neutral pH, leads to dual fluorescence. The band peaking at ...

We describe the one-pot synthesis of a large variety of nucleic acid bases and related compounds from formamide in the presence of zirconium minerals as catalysts. The major products observed are: purine, 2-hydroxy pyrimidine, 5-hydroxy pyrimidine, isocytosine, adenine, urea, and carbodiimide. The synthesis of low molecular weight amides and carboxylic ...

We use solution NMR techniques to analyze the organic/inorganic interface of CdSe quantum dots (Q-CdSe) synthesized using oleic acid as a surfactant. It is shown that the resulting Q-CdSe are stabilized by tightly bound oleic acid species that only exchange upon addition of free oleic acid. The NMR analysis points ...

The M13 bacteriophage has been demonstrated to be a robust scaffold for bionanomaterial development. In this paper, we report on the chemical modifications of three kinds of reactive groups, i.e., the amino groups of lysine residues or N-terminal, the carboxylic acid groups of aspartic acid or glutamic acid residues, and ...

A novel, efficient, and expedient route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed starting from readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl triflates.

A series of acylated chitin derivatives was prepared by reacting chitin in a solution of trifluoroacetic anhydride and each of the cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl carboxylic acids. The degree of O-acyl substitution was in a range of 1.1-1.4 depending upon the nature of the cyclic acid added, as determined ...

Genetic factors within the major histocompatibility locus (MHC) have been shown to influence body odors in mice. MHC-dependent preferences for body odors also have been reported in humans. The axillary glands are a key odor-forming organ in humans, and it is assumed that they provide behaviorally relevant odors. Volatile carboxylic ...

Aleuritic (9,10,16-trihydroxypalmitic) acid self-assembly on mica from solution has been studied using AFM, ATR-FTIR and MD simulations. The goal of this study is to define the role of hydroxyl groups in the interaction between molecules as reference data to understand the mechanism of formation of synthetic and natural biopolyesters from ...

Decomposition products formed/released during ammonia fiber expansion (AFEX) and dilute acid (DA) pretreatment of corn stover (CS) were quantified using robust mass spectrometry based analytical platforms. Ammonolytic cleavage of cell wall ester linkages during AFEX resulted in the formation of acetamide (25mg/g AFEX CS) and various phenolic amides (15mg/g AFEX ...

The synthesis of a new photolabile protecting group for carboxylic acids, alpha-carboxy-6-nitroveratryl (alphaCNV), is described. Bromide 3, prepared in four steps from 3,4-dimethoxyphenylacetic acid, was used to alkylate carboxylic acids under mild conditions in good yield. Palladium-catalyzed deallylation afforded the acids 4a-h, which underwent rapid and quantitative photolysis at wavelengths ...

The interface of electron-selective ZnO in inverted polymer bulk-heterojunction (BHJ) solar cells was modified with a series of fullerene-based self-assembled monolayers (C(60)-SAM) containing different anchoring groups (catechol, carboxylic acid, and phosphonic acid), linkage location, and functionalization. The formation of the C(60)-SAM to the surface of ZnO was investigated by processing ...

Amides as neutral and hydrophobic internucleoside linkages in RNA are highly interesting modifications for RNA interference. However, testing amides in siRNAs is hampered by the shortage of efficient methods to synthesize the monomeric building blocks, the nucleoside amino acid equivalents. This paper reports an efficient synthesis of protected ribonucleoside 5'-amino ...

An unexpected coupling reaction of arene carboxylic acid with nitroethane via a combination of decarboxylation and dehydrogenation is described. The method provides exclusively (E)-beta-nitrostyrenes.

A new class of oxadiazoles is prepared by treating aminosulfonylacetic acids with different carboxylic acid hydrazides. Interconversion of oxadiazoles to thiadiazoles is carried out with thiourea. The compounds are screened for antimicrobial and antioxidant activities.

Application of a laccase mediator system (an L stage) to TCF and ECF bleached pulp from Eucalyptus globulus with low residual lignin content (KN(lig)1.0) provides useful information about its effects on hexenuronic acids, functional groups (carboxyl and carbonyl) and electrokinetic properties such as zeta potential and surface charge. The use ...

Statins are cholesterol-lowering pharmaceuticals and commonly prescribed drugs in European countries. Their discharge into the aquatic environment has increased in the last few years and they are present at detectable levels in most sewage effluents. The aim of the present study was to quantify the cytotoxic effects of acid and ...

A helical aromatic oligoamide foldamer encapsulates tartaric acid with exceptional affinity, selectivity, and diastereoselectivity. The structure of the complex has been elucidated both in solution by NMR spectroscopy and in the solid state by X-ray crystallography, making it possible to rationalize the strong effects observed, particularly the role of hydrogen ...

The reactivity of radical cation carboxylic acids is investigated on the basis of mass spectrometry, infrared-vacuum ultraviolet (IR-VUV) photoionization spectroscopy, and high level correlated ab initio calculations. Their reactivity is found to be highly conformation specific and is governed by their initial charge distribution following ionization. In the present work, ...

A handheld Raman spectrometer (Ahura First Defender) was tested for the unambiguous identification of biomolecules (pure amino acids, carboxylic acids, saccharides and trehalose) in the solid state under outdoor conditions (including moderate climate conditions as well as cold temperatures and high altitudes). The biomolecules investigated represent important objects of interest ...

Volatile methyl esters are common constituents of plant volatiles with important functions in plant defense. To study the biosynthesis of these compounds, especially methyl anthranilate and methyl salicylate, we identified a group of methyltransferases that are members of the SABATH enzyme family in maize (Zea mays). In vitro biochemical characterization ...

Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under nitrogen atmosphere. Purification with concentrated nitric acid introduced approximately 0.1 mol/g of carboxylic acid groups as found by acid-base titrimetric analysis. XRD pattern showed the 0.15 mol/g basic graphitic structure of these nano carbon materials. ...

We developed a fluorous scavenging-derivatization method for reagent peak-free liquid chromatography (LC)-fluorescence analysis of carboxylic acids. In this method, carboxylic acids were fluorescently derivatized with 1-pyrenemethylamine in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 1-hydroxy-1H-benzotriazole. Residual excess unreacted reagent was tagged with 2-(perfluorooctyl)ethyl isocyanate and could be selectively removed by microfluorous solid-phase ...

In this paper, we describe the SAR of ozonide carboxylic acid OZ78 (1) as the first part of our search for a trematocidal synthetic peroxide drug development candidate. We found that relatively small structural changes to 1 resulted most commonly in loss of activity against Fasciola hepatica in vivo. A ...

A novel species of amides formed from degradation of one of the most important key intermediates in Maillard hexose chemistry-1-deoxyhexo-2,3-diulose-was investigated. In 1-deoxyhexo-2,3-diulose/N(alpha)-t-BOC-lysine reaction mixtures four amides, N(epsilon)-acetyl lysine, N(epsilon)-formyl lysine, N(epsilon)-lactoyl lysine and N(epsilon)-glycerinyl lysine, were identified and their structures verified by authentic reference standards. Amides and corresponding carboxylic ...

The role of selected carboxylic acids and their potential to influence the glycation pattern and the enzymatic activity of lysozyme using glucose and ribose were investigated independently of the pH of the reaction medium. The model systems were incubated with and without selected carboxylic acids (maleic, acetic, oxalic, and citraconic) ...

A new substituted polythiophene derivative bearing malonic acid, poly(2-thiophen-3-yl-malonic acid), has been prepared and characterized using a strategy that combines both experimental and theoretical methodologies. The chemical structure of this material has been investigated using FTIR and (1)H NMR, and its molecular conformation has been determined using quantum mechanical calculations. ...

Herein, the concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied in several classic dipolar [3+2] cycloadditions involving azides, nitrile oxides, and nitrones as partners. These cycloadditions can be used to produce pharmaceutically interesting, small heterocyclic products, such as triazoles, isoxazoles, and isoxazolidines. These ...

Saturated and unsaturated fluorotelomer carboxylic acids (fluorotelomer acids: FTAs) represent important intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (PFCAs). Recent studies have detected FTAs at low concentrations (ng/L) in precipitation and surface waters; however, information regarding chronic toxicity is lacking. The present study assessed the chronic ...

The detection and identification of organic molecules on Mars are of prime importance to establish the existence of a possible ancient prebiotic chemistry or even a biological activity. To date, however, no complex organic compounds have been detected on Mars. The harsh environmental conditions at the surface of Mars are ...

Glutaric acid, a common short-chain aliphatic dicarboxylic acid, was investigated in the negative ion mode by subjecting its [M-H](-) ion to collision-induced dissociation (CID) experiments in an infinity ion cyclotron resonance (ICR) cell coupled to a hexapole-quadrupole-hexapole ion guide. A 12 Tesla magnet was used for high-resolution measurements. Two distinctive ...