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Showing papers on "Carboxylic acid published in 2015"


Journal ArticleDOI
TL;DR: Pine wood biochar was used as a 3-dimensional adsorbent to remove salicylic acid and ibuprofen from aqueous solutions as mentioned in this paper, and the results showed that the biochar can adsorb far more adsorbate compared to commercial activated carbons.

284 citations


Journal ArticleDOI
TL;DR: Integrated process of VFA production from waste with co-generation of H2 can be considered as a green and sustainable platform for value-addition and illustrated the role of initial pH on carboxylic acids synthesis.

276 citations


Journal ArticleDOI
TL;DR: A rhodium(III)-catalyzed carboxylic acid directed decarboxylative C-H/C-H cross-coupling of car boxylic acids with thiophenes has been developed.
Abstract: A rhodium(III)-catalyzed carboxylic acid directed decarboxylative CH/CH cross-coupling of carboxylic acids with thiophenes has been developed. With a slight adjustment of the reaction conditions based on the nature of the substrates, aryl carboxylic acids with a variety of substituents could serve as suitable coupling partners, and a broad variety of functional groups were tolerated. This method provides straightforward access to biaryl scaffolds with diverse substitution patterns, many of which have conventionally been synthesized through lengthy synthetic sequences. An illustrative example is the one-step gram-scale synthesis of a biologically active 3,5-substituted 2-arylthiophene by way of the current method.

192 citations


Journal ArticleDOI
TL;DR: A novel strategy for specific fluorescence labeling of sialic acid-imprinted core-shell nanoparticles equipped with nitrobenzoxadiazole (NBD) fluorescent reporter groups allowing environmentally sensitive fluorescence detection at convenient excitation and emission wavelengths is reported.
Abstract: The expression of cell surface glycans terminating with sialic acid (SA) residues has been found to correlate with various disease states there among cancer. We here report a novel strategy for specific fluorescence labeling of such motifs. This is based on sialic acid-imprinted core-shell nanoparticles equipped with nitrobenzoxadiazole (NBD) fluorescent reporter groups allowing environmentally sensitive fluorescence detection at convenient excitation and emission wavelengths. Imprinting was achieved exploiting a hybrid approach combining reversible boronate ester formation between p-vinylphenylboronic acid and SA, the introduction of cationic amine functionalities, and the use of an NBD-appended urea-monomer as a binary hydrogen-bond donor targeting the SA carboxylic acid and OH functionalities. The monomers were grafted from 200 nm RAFT-modified silica core particles using ethylene glycol dimethacrylate (EGDMA) as cross-linker resulting in a shell thickness of ca. 10 nm. The particles displayed strong affinity for SA in methanol/water mixtures (K = 6.6 × 10(5) M(-1) in 2% water, 5.9 × 10(3) M(-1) in 98% water, B(max) ≈ 10 μmol g(-1)), whereas binding of the competitor glucuronic acid (GA) and other monosaccharides was considerably weaker (K (GA) = 1.8 × 10(3) M(-1) in 98% water). In cell imaging experiments, the particles selectively stained different cell lines in correlation with the SA expression level. This was further verified by enzymatic cleavage of SA and by staining using a FITC labeled SA selective lectin.

186 citations


Journal ArticleDOI
Jian Kan1, Shijun Huang1, Jin Lin1, Min Zhang1, Weiping Su1 
TL;DR: The silver-catalyzed intermolecular Minisci reaction of aromatic carboxylic acids was developed, which enables a variety of aromatic oil acids to undergo decarboxylative coupling with electron-deficient arenes or heteroarenes regardless of the position of the substituents on the aromatic car boxylic acid.
Abstract: A long-standing challenge in Minisci reactions is achieving the arylation of heteroarenes by oxidative decarboxylation of aromatic carboxylic acids. To address this challenge, the silver-catalyzed intermolecular Minisci reaction of aromatic carboxylic acids was developed. With an inexpensive silver salt as a catalyst, this new reaction enables a variety of aromatic carboxylic acids to undergo decarboxylative coupling with electron-deficient arenes or heteroarenes regardless of the position of the substituents on the aromatic carboxylic acid, thus eliminating the need for ortho-substituted aromatic carboxylic acids, which were a limitation of previously reported methods.

165 citations


Journal ArticleDOI
TL;DR: End-group ionization approach is important for the design of new pH-responsive copolymer nano-objects as, unlike polyacids or polybases, only a minimal amount of added base (or acid) is required to drive the morphological transition.
Abstract: A carboxylic acid based reversible additionfragmentation transfer (RAFT) agent is used to prepare gels composed of worm-like diblock copolymers using two non-ionic monomers, glycerol monomethacrylate (GMA) and 2-hydroxypropyl methacrylate (HPMA). Ionization of the carboxylic acid end-group on the PGMA stabilizer block induces a worm-to-sphere transition, which in turn causes immediate degelation. This morphological transition is fully reversible as determined by TEM and rheology studies and occurs because of a subtle change in the packing parameter for the copolymer chains. A control experiment where the methyl ester derivative of the RAFT agent is used to prepare the same diblock copolymer confirms that no pH-responsive behavior occurs in this case. This end-group ionization approach is important for the design of new pH-responsive copolymer nano-objects as, unlike polyacids or polybases, only a minimal amount of added base (or acid) is required to drive the morphological transition.

158 citations


Journal ArticleDOI
08 Jan 2015-Nature
TL;DR: The use of this catalyst is demonstrated in the synthesis of the naturally occurring anti-tumour agent neopeltolide and in a single-step stereoselective gram-scale conversion of a renewable feedstock (oleic acid) to an anti-fungal agent, indicating that its utility may extend beyond Z-selective processes.
Abstract: A ruthenium–disulfide catalyst is presented that is effective in generating compounds of medical and industrial utility (alcohols that contain a phenol, an aldehyde, or a carboxylic acid) by room-temperature, inexpensive, high-yielding cross-metathesis. Catalytic olefin metathesis is one of the most widely used reactions in synthetic organic chemistry, but its utility has been limited by the dearth of chemical transformations that directly generate acyclic Z allylic alcohols. In this manuscript, the authors present an electronically modified ruthenium-disulphide catalyst that is uniquely effective in generating compounds of medical and industrial utility (alcohols containing a phenol, an aldehyde or a carboxylic acid) by room-temperature, inexpensive, high-yielding cross-metathesis. The efficiency of the catalyst is demonstrated in the synthesis of naturally occurring antitumour agent neopeltolide and a single-step stereoselective gram-scale conversion of a renewable feedstock to an antifungal agent. Olefin metathesis catalysts provide access to molecules that are indispensable to physicians and researchers in the life sciences1,2. A persisting problem, however, is the dearth of chemical transformations that directly generate acyclic Z allylic alcohols, including products that contain a hindered neighbouring substituent or reactive functional units such as a phenol, an aldehyde, or a carboxylic acid. Here we present an electronically modified ruthenium–disulfide catalyst that is effective in generating such high-value compounds by cross-metathesis. The ruthenium complex is prepared from a commercially available precursor and an easily generated air-stable zinc catechothiolate. Transformations typically proceed with 5.0 mole per cent of the complex and an inexpensive reaction partner in 4–8 hours under ambient conditions; products are obtained in up to 80 per cent yield and 98:2 Z:E diastereoselectivity. The use of this catalyst is demonstrated in the synthesis of the naturally occurring anti-tumour agent neopeltolide and in a single-step stereoselective gram-scale conversion of a renewable feedstock (oleic acid) to an anti-fungal agent. In this conversion, the new catalyst promotes cross-metathesis more efficiently than the commonly used dichloro–ruthenium complexes, indicating that its utility may extend beyond Z-selective processes.

155 citations


Journal ArticleDOI
TL;DR: This is the first cobalt-catalyzed hydrogenation of esters to the corresponding alcohols, and the evidence indicates the unprecedented involvement of ester enolate intermediates.
Abstract: The atom-efficient and environmentally benign catalytic hydrogenation of carboxylic acid esters to alcohols has been accomplished in recent years mainly with precious-metal-based catalysts, with few exceptions. Presented here is the first cobalt-catalyzed hydrogenation of esters to the corresponding alcohols. Unexpectedly, the evidence indicates the unprecedented involvement of ester enolate intermediates.

139 citations


Journal ArticleDOI
TL;DR: A pyridine-type ligand is developed that overcomes this limitation of the N-methoxyamide auxiliary, leading to a significant improvement of β-arylation of carboxylic acid derivatives, especially α-amino acids.
Abstract: Pd-catalyzed β-C–H functionalizations of carboxylic acid derivatives using an auxiliary as a directing group have been extensively explored in the past decade. In comparison to the most widely used auxiliaries in asymmetric synthesis, the simplicity and practicality of the auxiliaries developed for C–H activation remains to be improved. We previously developed a simple N-methoxyamide auxiliary to direct β-C–H activation, albeit this system was not compatible with carboxylic acids containing α-hydrogen atoms. Herein we report the development of a pyridine-type ligand that overcomes this limitation of the N-methoxyamide auxiliary, leading to a significant improvement of β-arylation of carboxylic acid derivatives, especially α-amino acids. The arylation using this practical auxiliary is applied to the gram-scale syntheses of unnatural amino acids, bioactive molecules, and chiral bis(oxazoline) ligands.

135 citations


Journal ArticleDOI
TL;DR: The reaction presents a new type of acyl Michael addition using stable and easily accessible carboxylic acid to formally generate acyl anion through photoredox-catalyzed radical decarboxylation.

133 citations


Journal ArticleDOI
TL;DR: In this article, composite membranes are fabricated by incorporating amino acid-functionalized graphene oxide (GO-DA-Cys) nanosheets into a sulfonated poly(ether ether ketone) (SPEEK) polymer matrix.
Abstract: Composite membranes are fabricated by incorporating amino acid-functionalized graphene oxide (GO-DA-Cys) nanosheets into a sulfonated poly(ether ether ketone) (SPEEK) polymer matrix. Graphene oxide (GO) nanosheets are functionalized with amino acids through a facile two-step method using dopamine (DA) and cysteine (Cys) in succession. The CO2 separation performance of the as-prepared membranes is evaluated for CO2/CH4 and CO2/N2 systems. GO nanosheets increase more tortuous paths for larger molecules, enhancing the diffusivity selectivity. Amino acids with carboxylic acid and primary amine groups simultaneously enhance the solubility selectivity and reactivity selectivity. Accordingly, CO2 molecules can transport quickly due to the enhanced selectivity. The optimum separation performance is achieved at the GO-DA-Cys content of 8 wt% with selectivities of 82 and 115 for CO2/CH4 and CO2/N2, respectively, and a CO2 permeability of 1247 Barrer, significantly surpassing the Robeson upper bound reported in 2008. Besides, the mechanical and thermal stabilities of the composite membranes are also improved compared with the pristine SPEEK membrane.

Journal ArticleDOI
TL;DR: A recent breakthrough is described that enables the catalytic conversion of amides into esters for the first time.
Abstract: Breaking good: The amide bond is widely recognized as the strongest bond among the carboxylic acid derivatives. Therefore, the potential of amides to serve as synthetic building blocks has remained mostly untapped thus far. This Highlight describes a recent breakthrough that enables the catalytic conversion of amides into esters for the first time.

Journal ArticleDOI
TL;DR: It is now clear that Sm(II)-mediated ET to carboxylic acid derivatives constitutes a general strategy for inverting the polarity of the carbonyl, allowing nucleophilic carbon-centered radicals to be formed and exploited in novel chemical processes.
Abstract: ConspectusReductive electron transfer (ET) to organic compounds is a powerful method for the activation of substrates via the formation of radicals, radical anions, anions, and dianions that can be exploited in bond-cleaving and bond-forming processes. Since its introduction to the synthetic community in 1977 by Kagan, SmI2 has become one of the most important reducing agents available in the laboratory. Despite its widespread application in aldehyde and ketone reduction, it was widely accepted that carboxylic acid derivatives could not be reduced by SmI2; only recently has our work led to this dogma being overturned, and the reduction of carboxylic acid derivatives using SmI2 can now take its place alongside aldehyde/ketone reduction as a powerful activation mode for synthesis. In this Account, we set out our studies of the reduction of carboxylic acid derivatives using SmI2, SmI2–H2O, and SmI2–H2O–NR3 and the exploitation of the unusual radical anions that are now accessible in unprecedented carbon–carb...

Journal ArticleDOI
TL;DR: The first catalytic decarboxylative fluorination reaction based on the nucleophilic fluoride ion is described, which allows the facile replacement of various aliphatic carboxylic acid groups with fluorine.
Abstract: We describe the first catalytic decarboxylative fluorination reaction based on the nucleophilic fluoride ion. The reported method allows the facile replacement of various aliphatic carboxylic acid groups with fluorine. Moreover, the potential of this method for PET imaging has been demonstrated by the successful 18F labeling of a variety of carboxylic acids with radiochemical conversions up to 50 %, representing a targeted decarboxylative 18F labeling method with no-carrier-added [18F]fluoride. Mechanistic probes suggest that the reaction proceeds through the interaction of the manganese catalyst with iodine(III) carboxylates formed in situ from iodosylbenzene and the carboxylic acid substrates.

Journal ArticleDOI
TL;DR: Highly selective decarboxylative ortho-heteroarylation of aromatic carboxylic acids with various heteroarenes has been developed through Rh(III)-catalyzed two-fold C-H activation, which exhibits a wide substrate scope.

Journal ArticleDOI
TL;DR: In this paper, the effects of carboxylic acids formed in the proceeding of the degradation of organic pollutants on the photo-Fenton reactions were discussed, and a kinetic model simulating the dynamic behaviors of iron redox cycle and OH radical generation was developed.

Journal ArticleDOI
Yong Xia1, Lili Lin1, Fenzhen Chang1, Xuan Fu1, Xiaohua Liu1, Xiaoming Feng1 
TL;DR: A highly efficient asymmetric ring-opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N'-dioxide-scandium(III) complex as catalyst.
Abstract: A highly efficient asymmetric ring-opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N'-dioxide-scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99% yield and 95% ee. This is also the first example of one catalytic system working for the ring-opening reaction of donor-acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version.

Journal ArticleDOI
TL;DR: This work determined metabolic stability and metabolites of N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole- 3-carboxamide (AB-PINACA) and 5-fluoro-AB- PINACA (5F-AB -PINACA), two new synthetic cannabinoids, and investigated if results were similar.
Abstract: Whereas non-fluoropentylindole/indazole synthetic cannabinoids appear to be metabolized preferably at the pentyl chain though without clear preference for one specific position, their 5-fluoro analogs’ major metabolites usually are 5-hydroxypentyl and pentanoic acid metabolites. We determined metabolic stability and metabolites of N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (AB-PINACA) and 5-fluoro-AB-PINACA (5F-AB-PINACA), two new synthetic cannabinoids, and investigated if results were similar. In silico prediction was performed with MetaSite (Molecular Discovery). For metabolic stability, 1 μmol/L of each compound was incubated with human liver microsomes for up to 1 h, and for metabolite profiling, 10 μmol/L was incubated with pooled human hepatocytes for up to 3 h. Also, authentic urine specimens from AB-PINACA cases were hydrolyzed and extracted. All samples were analyzed by liquid chromatography high-resolution mass spectrometry on a TripleTOF 5600+ (AB SCIEX) with gradient elution (0.1% formic acid in water and acetonitrile). High-resolution full-scan mass spectrometry (MS) and information-dependent acquisition MS/MS data were analyzed with MetabolitePilot (AB SCIEX) using different data processing algorithms. Both drugs had intermediate clearance. We identified 23 AB-PINACA metabolites, generated by carboxamide hydrolysis, hydroxylation, ketone formation, carboxylation, epoxide formation with subsequent hydrolysis, or reaction combinations. We identified 18 5F-AB-PINACA metabolites, generated by the same biotransformations and oxidative defluorination producing 5-hydroxypentyl and pentanoic acid metabolites shared with AB-PINACA. Authentic urine specimens documented presence of these metabolites. AB-PINACA and 5F-AB-PINACA produced suggested metabolite patterns. AB-PINACA was predominantly hydrolyzed to AB-PINACA carboxylic acid, carbonyl-AB-PINACA, and hydroxypentyl AB-PINACA, likely in 4-position. The most intense 5F-AB-PINACA metabolites were AB-PINACA pentanoic acid and 5-hydroxypentyl-AB-PINACA.

Journal ArticleDOI
TL;DR: The evolution of an Escherichia coli MG1655 derivative at neutral pH in minimal media produced a strain with increased tolerance to exogenous octanoic acid, with a more dynamic membrane composition, showing both a larger number of significant changes and larger fold changes in the relative abundance of membrane lipids.

Journal ArticleDOI
TL;DR: A series of nine complexes and 109 literature examples containing a carboxylic acid functional group and a pyridine functional group on separate molecules follow the ΔpKa rule such that proton transfer occurs at values above 3 to form a molecular salt and none at values below 0 to form co-crystal.
Abstract: A series of nine complexes and 109 literature examples containing a carboxylic acid functional group and a pyridine functional group on separate molecules follow the ΔpKa rule such that proton transfer occurs at values above 3 to form a molecular salt and none at values below 0 to form a co-crystal. In the intermediate range, there is a predominance of molecular salt over co-crystal formation. The complexes discussed show that calculated pKa's are good predictors of the outcome.

Journal ArticleDOI
TL;DR: In this paper, the Diels-Alder reaction of furan and acrylic acid was run at 298 K and was catalyzed by Lewis acidic (Hf-, Zr-, and Sn-Beta) zeolite catalysts, and achieving a high turnover frequency (∼2 h −1) and no side reactions were observed.
Abstract: Routes to benzoic acid starting from furan—obtained from hemicellulose in high yield—and methyl acrylate are reported. These routes involve Diels–Alder and dehydration reactions of furan and acrylic acid (or methyl acrylate) in a two-step reaction protocol that minimizes side reactions. The Diels–Alder reaction of furan and methyl acrylate (or acrylic acid) was run at 298 K and was catalyzed by Lewis acidic (Hf-, Zr-, and Sn-Beta) zeolite catalysts, and achieving a high turnover frequency (∼2 h–1) and no side reactions were observed. The oxanorbornene product was dehydrated at low temperatures (298 to 353 K) in mixtures of methanesulfonic acid and acetic anhydride in 96% yield. This is compared to an only 1.7% yield of methyl benzoate obtained for the dehydration of the oxanorbornene in neat methanesulfonic acid. The effect of oxanorbornene concentration and stereochemistry was found not to decrease the yield of aromatics, while dehydration of the carboxylic acid form of the oxanorbornene led to a decreas...

Journal ArticleDOI
TL;DR: In this article, the first metal-catalyzed protocol for direct amidation of nonactivated carboxylic acids at ambient temperature (26 °C) is presented, employing a commercial hafnium complex, [Hf(Cp)2Cl2], as catalyst.
Abstract: Herein, the first example of a metal-catalyzed protocol for direct amidation of nonactivated carboxylic acids at ambient temperature (26 °C) is presented. The mild reaction conditions give rise to high yields of a range of amides in reaction times as short as 90 min, employing a commercial hafnium complex, [Hf(Cp)2Cl2], as catalyst. Amino acids are transformed into their corresponding amides without racemization, and the catalyst displays full selectivity for the amidation of carboxylic acids over esters. Electronic properties of the carboxylic acids were found to have a strong influence on the rate of the amidation reaction, and the need for a balanced amount of molecular sieves was observed to be highly important for optimal reaction outcome.

Journal ArticleDOI
TL;DR: The substantially higher adsorption of propionic acid demonstrated by IR spectroscopy and the higher reactivity to O2 exchange reactions with the more active catalyst indicate that the higher concentration of active oxygen defects on m-ZRO2 compared to t-ZrO2 causes the higher activity of Ni/m-Z rO2.
Abstract: The role of the specific physicochemical properties of ZrO2 phases on Ni/ZrO2 has been explored with respect to the reduction of stearic acid. Conversion on pure m-ZrO2 is 1.3 times more active than on t-ZrO2 , whereas Ni/m-ZrO2 is three times more active than Ni/t-ZrO2 . Although the hydrodeoxygenation of stearic acid can be catalyzed solely by Ni, the synergistic interaction between Ni and the ZrO2 support causes the variations in the reaction rates. Adsorption of the carboxylic acid group on an oxygen vacancy of ZrO2 and the abstraction of the α-hydrogen atom with the elimination of the oxygen atom to produce a ketene is the key to enhance the overall rate. The hydrogenated intermediate 1-octadecanol is in turn decarbonylated to heptadecane with identical rates on all catalysts. Decarbonylation of 1-octadecanol is concluded to be limited by the competitive adsorption of reactants and intermediate. The substantially higher adsorption of propionic acid demonstrated by IR spectroscopy and the higher reactivity to O2 exchange reactions with the more active catalyst indicate that the higher concentration of active oxygen defects on m-ZrO2 compared to t-ZrO2 causes the higher activity of Ni/m-ZrO2 .

Journal ArticleDOI
TL;DR: Pyrrolidine-derived propargylamines, in the absence of directing groups, can be transformed to the corresponding allenes without loss of enantiopurity.
Abstract: Pyrrolidine and related amines undergo asymmetric A3 reactions in the presence of copper iodide and an easily accessible cocatalyst possessing both a carboxylic acid and a thiourea moiety. Propargylamines are obtained with up to 96% ee, and catalyst loadings can be as low as 1 mol %. Pyrrolidine-derived propargylamines, in the absence of directing groups, can be transformed to the corresponding allenes without loss of enantiopurity.

Journal ArticleDOI
TL;DR: In this paper, the influence of the carboxylic acid chemical structure on the properties of poly(3-hexylthiophene) (P3HT) prepared via DArP was investigated.
Abstract: Carboxylic acids are known to have a profound effect on the rate of direct arylation. Despite this, little attention has been paid to them as additives for direct arylation polymerization (DArP). Here we report the influence of the carboxylic acid chemical structure on the properties of poly(3-hexylthiophene) (P3HT) prepared via DArP. We study the effect that acid pKa, steric bulk, and backbone cyclization have on the reactivity of the DArP catalytic system. We found that pKa values do not correlate with DArP reactivity in the pKa range of 4.76–5.05. The increase of acid size in the classes of linear, secondary, and tertiary acids leads to a continuous increase in polymer yield and molecular weight, whereas for the case of cyclic secondary acids the trend is reversed and a decrease of acid size leads to an increase in polymer yield and molecular weight in an alternating (zigzag) fashion depending on whether the acid contains an even or odd number of carbons. A profound enhancement of reactivity was found ...

Journal ArticleDOI
TL;DR: In this article, acid additive effects in the Ir-catalyzed C-H amidation of arylphosphoryl compounds were examined. And the role of carboxylic acid additive operating both in the generation of an iridacyclic intermediate and in the protodemetalation process to release amidated products.

Journal ArticleDOI
TL;DR: It is argued that this behavior stems from the dissociative adsorption of carboxylic acids at the oxide surface, and both proton and carboxylate moieties must be regarded as X- type ligands yielding a combined X2 binding motif that allows for self-adsorption and exchange for L-type ligands.
Abstract: Ligand exchange is central in the processing of inorganic nanocrystals (NCs) and requires understanding of surface chemistry. Studying sterically stabilized HfO2 and ZrO2 NCs using 1H solution NMR and IR spectroscopy as well as elemental analysis, this paper demonstrates the reversible exchange of initial oleic acid ligands for octylamine and self-adsorption of oleic acid at NC surfaces. Both processes are incompatible with an X-type binding motif of carboxylic acids as reported for sulfide and selenide NCs. We argue that this behavior stems from the dissociative adsorption of carboxylic acids at the oxide surface. Both proton and carboxylate moieties must be regarded as X-type ligands yielding a combined X2 binding motif that allows for self-adsorption and exchange for L-type ligands.

Journal ArticleDOI
TL;DR: Various allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere to afford branched carboxylic acids predominantly.
Abstract: Various allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere (1 atm). This carboxylation proceeded in a highly regioselective manner to afford branched carboxylic acids predominantly. The β,γ-unsaturated carboxylic acid thus obtained was successfully converted into an optically active γ-butyrolactone, a known intermediate of (R)-baclofen.

Journal ArticleDOI
TL;DR: In this paper, the ability of two commercially available nanofiltration membranes (NF) to efficiently separate a mixture of carboxylic acids while simultaneously retaining sugars in actual lignocellulosic biomass digestion liquor was evaluated.

Journal ArticleDOI
TL;DR: The short relative half-life of the acyl glucuronide (high acyl migration rate), high daily dose and detection of acyl CoA conjugates, or further metabolites derived from acyl coA together seem to indicate that carboxylic acid-containing drugs have a higher probability to cause drug-induced liver injury (DILI).
Abstract: Many carboxylic acid-containing drugs are associated with idiosyncratic drug toxicity (IDT), which may be caused by reactive acyl glucuronide metabolites. The rate of acyl migration has been earlier suggested as a predictor of acyl glucuronide reactivity. Additionally, acyl Coenzyme A (CoA) conjugates are known to be reactive. Here, 13 drugs with a carboxylic acid moiety were incubated with human liver microsomes to produce acyl glucuronide conjugates for the determination of acyl glucuronide half-lives by acyl migration and with HepaRG cells to monitor the formation of acyl CoA conjugates, their further conjugate metabolites, and trans-acylation products with glutathione. Additionally, in vitro cytotoxicity and mitochondrial toxicity experiments were performed with HepaRG cells to compare the predictability of toxicity. Clearly, longer acyl glucuronide half-lives were observed for safe drugs compared to drugs that can cause IDT. Correlation between half-lives and toxicity classification increased when “r...