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This study evaluates the influence of various substrates (glucose, glycerol, and acetic acid) on the growth and metabolite production of Yarrowia lipolytica in fed-batch bioreactors. The primary aim is to understand how substrate choice impacts lipid and β-carotene production, critical for bioenergy and bioproducts. The study demonstrates that the choice of substrate significantly influences biomass yield, lipid content, and β-carotene levels. Among the substrates tested, glycerol yielded the highest biomass concentration of 5.31 g/L. Glucose led to the highest lipid content, with a yield of 35.8% (g lipids/g biomass), while acetic acid resulted in the highest lipid concentration, reaching 1.42 g/L. In terms of β-carotene production, glucose showed the highest content per cell at 63.3 mg/g, whereas glycerol led to the highest overall concentration of 202 mg/L. These findings highlight Y. lipolytica's versatility and potential as a flexible platform to produce lipids and β-carotene, which are essential for developing sustainable biofuels and bioproducts. The study underscores the significant variations in metabolite production based on substrate choice, emphasizing on the importance of tailored strategies to optimize industrial applications. Further research may explore optimizing fermentation conditions to enhance production yields, making this yeast a viable option for various biotechnological applications. Key points: Y. lipolytica produces biodiesel and β-carotene from low-cost substrates. Glucose, glycerol, or acetic acid act differently as substrates on Y. lipolytica. Cheap substrates derived from pollutants can be used for biofuels and bioproducts. [ABSTRACT FROM AUTHOR]

Phenols play a crucial role as core structural motifs in natural products and also serve as fundamental building blocks in synthetic chemistry. Apart from the known protocols for the conversion of aryl precursors to phenols (i. e., decarboxylative oxygenation), we report here the efficient synthesis of phenols from the stable and readily available benzylic carboxylic acids under mild reaction conditions. The photocatalytic conversion of carboxylic acids to peroxides is a crucial step in this strategy, allowing the subsequent C−O bond formation via Hock rearrangement. [ABSTRACT FROM AUTHOR]

Discovered in 1822, the haloform reaction is one of the oldest synthetic organic reactions. The haloform reaction enables the synthesis of carboxylic acids, esters or amides from methyl ketones. The reaction proceeds via exhaustive α‐halogenation and then substitution by a nucleophile to liberate a haloform. The methyl group therefore behaves as a masked leaving group. The reaction methodology has undergone several important developments in the last 200 years, transitioning from a diagnostic test of methyl ketones to a synthetically useful tool for accessing complex esters and amides. The success of the general approach has been exhibited through the use of the reaction in the synthesis of many different complex molecules in fields ranging from natural product synthesis, pharmaceuticals, agrochemicals, fragrants and flavourings. The reaction has not been extensively reviewed since 1934. Therefore, herein we provide details of the history and mechanism of the haloform reaction, as well as an overview of the developments in the methodology and a survey of examples, particularly in natural product synthesis, in which the haloform reaction has been used. [ABSTRACT FROM AUTHOR]

This account describes the latest developments on 3d-metal-catalyzed single-electron-transfer (SET)-induced strategies that use carboxylic acids and their synthetic equivalents as substrates. In general, 3d-metal-promoted SET-mediated transformations of free carboxylic acids proceed readily via the formation of carboxylate radicals, whilst those of carboxylic acid equivalents, bearing an N-donor substituent, proceed via the formation of α-carbo radicals. The advantages of these strategies combine the low-cost of carboxylic acid starting materials and 3d metal catalysts with the possibility of realizing structurally diverse ranges of compounds in an atom- and step-economic manner. Developments primarily achieved by our group and a few by other researchers on this topic are discussed in this account. 1 Introduction 2 Mechanistic Considerations of 3d-Metal-Catalyzed SET-Mediated Transformations 3 Developments Based on SET-Mediated Transformations of Carboxylic Acids 4 Developments Based on SET-Mediated Transformations of Carboxylic Acid Equivalents 5 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Boronate esters are highly valued in synthetic and pharmaceutical industries for their versatility in creating C—C and C—X bonds. They also find applications as catalysts in chemical transformations as well as stimuli‐responsive materials in materials science. Some alkyl boronates themselves also show promising applications in medicinal chemistry. In the past few decades, chemists have been devoted to developing new methods or new starting materials for synthesizing boronate esters. Carboxylic acids and their derivatives are privileged chemical entities due to their readily availability or natural abundance, structural diversity, and chemical stability. Hence, the transformation of carboxylic acid and their derivatives to alkyl/aryl boronate esters has seen its fast development in the past decade. This review summarized the state‐to‐art development of decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives to aryl and alkyl boronate esters. Key Scientists: The decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives started only in the past decade. In 2016, the decarbonylative borylation of carboxylic esters and amides was reported by Zhuangzhi Shi and Magnus Reuping's groups. Then, in 2017, studies on the decarboxylative borylation of redox‐active esters such as NHPI esters started to receive increasing attention by Aggarwal, Baran, Fu, Glorius, and Li's groups. From 2018 to 2023, large numbers of studies on the decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives using transition‐metal‐catalyst, organo‐catalyst, or under photochemical or electrochemical conditions emerged. Due to space limitations, only pictures of scientists who have contributed more than two works in this area are shown herein. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Boronate esters are highly valued in synthetic and pharmaceutical industries for their versatility in creating C—C and C—X bonds. They also find applications as catalysts in chemical transformations as well as stimuli‐responsive materials in materials science. Some alkyl boronates themselves also show promising applications in medicinal chemistry. In the past few decades, chemists have been devoted to developing new methods or new starting materials for synthesizing boronate esters. Carboxylic acids and their derivatives are privileged chemical entities due to their readily availability or natural abundance, structural diversity, and chemical stability. Hence, the transformation of carboxylic acid and their derivatives to alkyl/aryl boronate esters has seen its fast development in the past decade. This review summarized the state‐to‐art development of decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives to aryl and alkyl boronate esters. Key Scientists: The decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives started only in the past decade. In 2016, the decarbonylative borylation of carboxylic esters and amides was reported by Zhuangzhi Shi and Magnus Reuping's groups. Then, in 2017, studies on the decarboxylative borylation of redox‐active esters such as NHPI esters started to receive increasing attention by Aggarwal, Baran, Fu, Glorius, and Li's groups. From 2018 to 2023, large numbers of studies on the decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives using transition‐metal‐catalyst, organo‐catalyst, or under photochemical or electrochemical conditions emerged. Due to space limitations, only pictures of scientists who have contributed more than two works in this area are shown herein. [ABSTRACT FROM AUTHOR]

After systematic realization of decarboxylative functionalization of carboxylic acids under heating conditions in our group, we herein reported an electrochemical method for Ni‐catalyzed decarboxylative oxygenation of arylacetic acids under open air conditions. The protocol provided corresponding carbonyls including aldehydes and ketones in moderate to satisfactory yields with good functional group tolerance, furthermore, the practicability and advantage of the method was highlighted through Ni‐catalyzed oxidative decarboxylation of carboxylic acid‐containing drugs and preformation of scalable transformation. Mechanistic studies demonstrated that the possible involvement of free radical intermediate in the conversion. [ABSTRACT FROM AUTHOR]

1,2,3,4‐Tetrakis(carboxyphenyl)benzene (CPB) forms a predictable ladder‐shaped porous motif through intermolecular hydrogen‐bonding of the carboxy groups. The stacking manner of the ladder motif, on the other hand, cannot be controlled, yielding a crystal structure with discrete inclusion spaces. To modulate the stacking manner, its derivative CPB(OMe) with methoxy substituent groups at 5,6‐positions was synthesized and crystallized to yield a crystalline hydrogen‐bonded organic framework (HOF), in which the ladder motifs are stacking with a different manner to form 1D inclusion channels, instead of discrete voids. Because of the channel structure, removal of the included solvent molecules can be easily conducted, and the resultant activated HOF CPB(OMe)‐a exhibited micropores with BET surface area of 199 m2 g−1, which is larger than that of the other HOF CPB‐a. [ABSTRACT FROM AUTHOR]

For wider use of starch in the production of biodegradable plastics, it is necessary to search for new effective plasticizers. In this study, the effect of seven deep eutectic solvents (DES) based on choline chloride and carboxylic acid (levulinic, lactic, malonic, itaconic, malic, tartaric and citric) on the properties of potato starch were investigated. For this purpose, the thermal and rheological properties of starch/DES mixtures were evaluated. The viscosity of aqueous starch/DES solutions was determined. Subsequently, the starch films were obtained by casting. To determine the plasticization efficiency, mechanical properties, crystallinity and moisture resistance were evaluated. The correlation between the properties of the starch films and the molecular structure of DES acidic component was revealed. [ABSTRACT FROM AUTHOR]

β‐(Trifluoromethyl)styrenes are potentially useful building blocks for the synthesis of organofluorine compounds because their electron‐deficient C=C double bonds can undergo diverse transformations. One of the most practical methods for preparing β‐(trifluoromethyl)styrenes is the decarboxylative trifluoromethylation of readily available cinnamic acid derivatives using the Langlois reagent as a less expensive trifluoromethyl source. We revisited the electrochemical decarboxylative trifluoromethylation of cinnamic acid derivatives to identify modified conditions that reduce the loading of the Langlois reagent without additional additives. The reaction mechanism was computationally investigated to gain insight into the dependence of the product yields on the aryl terminal groups. The synthetic utility of the obtained β‐(trifluoromethyl)styrenes was demonstrated by their transformation into 4‐aryl‐3‐(trifluoromethyl)pyrrolidines. [ABSTRACT FROM AUTHOR]

The new alkaloid lindelofamine N-oxide (1) and the known 1-exo-carboxypyrrolizidine (2) and the quaternary salt of the isoquinoline alkaloid O-methylarmepavine methyliodide (3) were isolated from Lindelofia macrostyla (Bunge) Popov for the first time. The structures were established by NMR spectroscopy, the absolute configuration was determined using X-ray diffraction analysis of the chiral centers of the last two as 1R,4R,8S and 1S, respectively. The new carboxylic acid (2S,3R)-2-hydroxy-2-isopropyl-3-{[(E)-2-methylbut-2-enoyl]oxy}butanoic acid, the structure and absolute configuration (2S,3R) of which were proven by NMR spectroscopy and an XSA, was also isolated. [ABSTRACT FROM AUTHOR]

The one‐carbon degradation  of aliphatic carboxylic acids has been studied using a H2IrCl6‐Ru(CO)4I2 bimetallic catalyst. Alkanes, RH, have been obtained from the corresponding RCOOH in good to near quantitative yields via a process that is thought to involve (i) a decarbonylation process that involves the formation of alkenes along with CO and H2O, (ii) a water–gas shift (WGS) reaction to give H2 and CO2, and (iii) the hydrogenation of the resulting alkenes. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of carboxylic acids to alcohols is generally difficult due to the low reactivity of the carboxy group, and the development of effective catalysts enabling high yields of the target alcohols at low reaction temperatures (<473 K) is challenging. Herein, we found that SiO2‐supported FeOx‐modified Ru (Ru−FeOx/SiO2) with the Fe/Ru molar ratio of 0.4 was an effective and reusable heterogeneous catalyst for the hydrogenation of carboxylic acids at a low reaction temperature of 413 K, providing the alcohols in high yields (up to 97 %). The addition of Fe species drastically suppressed the hydrogenolysis of the C−C bond of the alkyl chain to methane, leading to high selectivity to the alcohols. Based on the activity tests and catalyst characterizations, Ru metals were covered by the reduced Fe species, such as Fe metal or Fe2+, and the active site is the interface between the Fe species and Ru metals. From the reactivity comparison of the related compounds, the alcohol is synthesized via the formation of the aldehyde, and the reactivity of the alcohol is very low in the presence of carboxylic acids. As a result, the hydrogenolysis of the produced alcohol is suppressed, leading to the high selectivity of the alcohol. [ABSTRACT FROM AUTHOR]

Copper compounds in the form of fungicides are most commonly used as a measure of protection against vine diseases. Typically, around a dozen treatments are done throughout a year with a dispersion of approximately 5–10 kg of Cu per hectare. For many years, the remediation of heavy metals has often involved the use of ex-situ soil washing with chelating reagents. Amino acids have a lower metal chelation capability compared to EDTA and its derivatives, but they have numerous other advantages in comparison. The main goal of this research was to investigate the ability of 9 amino acids and one dipeptide to extract Cu from various vineyard soil samples and compare their chelating ability with other 'green' chelating agents. The average content of Cu extracted with amino acids is 34.7 ± 16.7 mg/kg or 30.3 ± 5.43 wt% relative to the pseudo-total content. This is more than what was extracted with carboxylic acid salts (9.91 ± 7.49 mg/kg or 8.45 ± 5.56 wt%) but less than with EDTA (98.5 ± 42.7 mg/kg or 79.9 ± 7.12 wt%). The descending order of tested amino acids relative to the removed Cu (mg/kg) is: His > Ser > Thr > Leu > Gly > Val > Phe > Gly-Gly ~ Ala > Arg. The results of this paper show that the amino acid structure is the most important factor for efficient Cu extraction, while the physicochemical properties of the vineyard soil have less impact. [ABSTRACT FROM AUTHOR]

Tailoring the properties of cellulose aerogel beads was investigated in the present study by using weak organic acids as coagulants. Three different weak acids were specifically chosen, acetic acid, lactic acid and citric acid. For comparative studies, a strong acid, hydrochloric acid was examined. The production of aerogel beads by conventional dropping technique was controlled and optimized for weak acids. Aerogels were characterized by density analyses, scanning electron microscopy, nitrogen adsorption–desorption analysis, X‐ray powder diffractometry and IR spectroscopy. In common, all the aerogel beads showed interconnected nanofibrillar network, high specific surface area, high pore volume, high porosity and meso‐ and macroporous structure. In particular, when the weakest acid (acetic acid) was used as coagulant in the regeneration bath, the lowest shrinkage was observed. As a result, the cellulose aerogel beads produced from acetic acid showed the highest values of specific surface area (423 m2 g−1) and pore volume (3.6 cm3 g−1). The porous structure can be tuned by the choice of regeneration bath, which has either strong acid or a high concentration of weak acid. The aerogel beads were pure and showed cellulose II crystallinity. Hence this study paves an alternative path way to tailor the properties of cellulose aerogel beads. [ABSTRACT FROM AUTHOR]

Glycinium oxalate (GO) and Bis(glycinium) oxalate (BGO) crystals are successfully grown using the slow evaporation solution growth technique. Following their growth, the crystals are subjected to a series of acoustic shock pulses. The effects of these shock pulses on the structural, optical, dielectric, and morphological properties of the crystals are comprehensively analyzed using various characterization techniques, including powder X‐ray diffraction (XRD), UV‐Visible spectroscopy, dielectric spectroscopy, and optical microscopy. Structural analysis through XRD reveals shifts in diffraction peak positions, indicating structural deformations. Fourier transform infrared spectroscopy analysis assesses the chemical stability of GO and BGO under shocked conditions. UV‐Visible spectroscopy shows alterations in optical transmission with successive shock pulses, attributed to structural and surface defects. Dielectric properties are investigated over a frequency range from 1 Hz to 1 MHz, revealing variations in dielectric constant and loss tangent, which provide insights into the electrical behavior of the materials under normal and shocked conditions. Optical and scanning electron microscopy examine surface morphology, visualizing defects induced by the shock pulses. This study highlights the significant impact of shock pulses on the structural properties, optical transmission, dielectric properties, and surface morphology of GO and BGO crystals, offering valuable information on their resilience under dynamic conditions and potential applications. [ABSTRACT FROM AUTHOR]

Sour taste, which is elicited by low pH, may serve to help animals distinguish appetitive from potentially harmful food sources. In all species studied to date, the attractiveness of oral acids is contingent on concentration. Many carboxylic acids are attractive at ecologically relevant concentrations but become aversive beyond some maximal concentration. Recent work found that Drosophila ionotropic receptors IR25a and IR76b expressed by sweet-responsive gustatory receptor neurons (GRNs) in the labellum, a peripheral gustatory organ, mediate appetitive feeding behaviors toward dilute carboxylic acids. Here, we disclose the existence of pharyngeal sensors in Drosophila melanogaster that detect ingested carboxylic acids and are also involved in the appetitive responses to carboxylic acids. These pharyngeal sensors rely on IR51b, IR94a, and IR94h, together with IR25a and IR76b, to drive responses to carboxylic acids. We then demonstrate that optogenetic activation of either Ir94a+ or Ir94h+ GRNs promotes an appetitive feeding response, confirming their contributions to appetitive feeding behavior. Our discovery of internal pharyngeal sour taste receptors opens up new avenues for investigating the internal sensation of tastants in insects.

We report an iron‐catalyzed decarboxylative C(sp3)−O bond‐forming reaction under mild, base‐free conditions with visible light irradiation. The transformation uses readily available and structurally diverse carboxylic acids, iron photocatalyst, and 2,2,6,6‐tetramethylpiperidine 1‐oxyl (TEMPO) derivatives as oxygenation reagents. The process exhibits a broad scope in acids possessing a wide range of stereoelectronic properties and functional groups. The developed reaction was applied to late‐stage oxygenation of a series of bio‐active molecules. The reaction leverages the ability of iron complexes to generate carbon‐centered radicals directly from carboxylic acids by photoinduced carboxylate‐to‐iron charge transfer. Kinetic, electrochemical, EPR, UV/Vis, HRMS, and DFT studies revealed that TEMPO has a triple role in the reaction: as an oxygenation reagent, an oxidant to turn over the Fe‐catalyst, and an internal base for the carboxylic acid deprotonation. The obtained TEMPO adducts represent versatile synthetic intermediates that were further engaged in C−C and C‐heteroatom bond‐forming reactions using commercial organo‐photocatalysts and nucleophilic reagents. [ABSTRACT FROM AUTHOR]

Palladium‐catalyzed enantioselective C(sp3)−H functionalization reactions has attracted considerable attention due to its ability for the synthesis of enantiomerically enriched molecules and stimulation of novel retrosynthetic disconnections. Understanding the reaction mechanism, especially the stereochemical process of the reaction, is crucial for the rational design of more efficient catalytic systems. Previously, we developed a Pd(II)/sulfoxide‐2‐hydroxypridine (SOHP) catalytic system for asymmetric C(sp3)−H functionalization reactions. In this study, we focused on unraveling the chemistry of chiral palladacycles involved in the Pd(II)‐catalyzed enantioselective C(sp3)−H functionalization. We have isolated key palladacycle intermediates involved in the enantioselective β‐C(sp3)−H arylation of carboxylic acids catalyzed by the Pd(II)/SOHP system. These palladacycles, exhibiting ligand‐induced chirality, provided a significant opportunity to investigate the stereochemical process and the ligand effect in this asymmetric C−H functionalization. Our investigation provided direct evidence for the C−H palladation step as the enantioselectivity‐determining step, which forms diastereomeric palladacycles that exhibited preservation of chirality in the functionalization step. DFT calculations provided insights into the chiral induction in palladacycle formation. This work highlights the value of chiral palladacycle chemistry in offering mechanistic insights into the Pd(II)‐catalyzed asymmetric C(sp3)−H functionalization reactions. [ABSTRACT FROM AUTHOR]

We designed and synthesized a ureido‐linked zinc bisporphyrinate [Zn2(UBis)]. CD spectra show that this zinc bisporphyrinate has the ability to sense the chirality of chiral carboxylic acids without derivatization. Our studies suggest that the phenyl ring in the linker forms π‐π interactions with porphyrin planes and that the carboxylic acid is coordinated to the zinc in the host‐guest complex. DFT calculations show that the bisporphyrin adopts a "Z"‐shaped configuration, and that the ureido group forms hydrogen bonds with carboxylic acids. The combination of π‐π interactions, coordination interactions and hydrogen bonding interactions leads to the chirality sensing ability of [Zn2(UBis)]. [ABSTRACT FROM AUTHOR]

Functional group compatibility in an amide bond cleavage reaction with hydrazine was evaluated for 26 functional groups in the functional group evaluation (FGE) kit. Accurate and rapid evaluation of the compatibility of functional groups, such as nitrogen-containing heterocycles important in drug discovery research, will enhance the application of this reaction in drug discovery research. These data will be used for predictive studies of organic synthesis methods based on machine learning. In addition, these studies led to discoveries such as the unexpected positive additive effects of carboxylic acids, indicating that the FGE kit can propel serendipitous discoveries. [ABSTRACT FROM AUTHOR]

This article explores the electrochemical hydro- and deuterocarboxylation of allenes using carbon dioxide (CO2) and deuterium oxide (D2O) as starting materials. The authors discuss the challenges of activating CO2 and propose photochemical and electrochemical methods as potential solutions. They present their own findings on the electrochemical hydrocarboxylation and deuterocarboxylation of allenes, demonstrating good regioselectivity and high yields of carboxylic acids. The authors suggest possible mechanisms for these reactions and highlight their potential applications in reaction mechanism studies and drug development. The article also provides detailed experimental procedures and results, including information on the synthesis and characterization of various compounds. [Extracted from the article]

The narrow pH application range and lower utilization of ferrous ions (Fe(II)) restrict the application of Fe(II)/persulfate (PS) technology. In this paper, simulated sunlight and citric acid (Cit) as a chelator were introduced in an Fe(II)/PS system to overcome the drawbacks and enhance the degradation of typical antibiotic sulfamethoxazole (SMX) in secondary wastewater. The degradation kinetics, mechanism, and influence factors of SMX in a sunlight/Fe(II)/Cit/PS system and a sunlight/Fe(II)/Cit system as a comparable system were investigated. The removal efficiency of SMX can reach 71.15% and 85.25% in the sunlight/Fe(II)/Cit system and sunlight/Fe(II)/Cit/PS system with 0.1 mM Fe(II), 0.6 mM Cit, and 1 mM PS. The increase of Fe(II) concentration in both systems proved that sunlight promoted the regeneration of Fe(II) from the ferric ion chelates. However, the Fe(II) concentration decreased after 30 min in the sunlight/Fe(II)/Cit/PS system because of the decomposition of Cit. Radical quencher experiments indicated that SO4·−, ·OH, and O2·− contributed 2.48%, 88.43%, and 6.91% to the removal of SMX, respectively. Electron paramagnetic resonance spectra also proved the formation of ·OH and O2·−. The degradation of SMX was proposed to proceed via isomerization, cleavage of S–N bond, and hydroxylation. Overall, the sunlight/Fe(II)/Cit/PS process can be used as an advanced treatment technology for antibiotics in municipal wastewater. [ABSTRACT FROM AUTHOR]

The objective of the study is to synthesize economical and facile ethylenediamine (ED) based protic ionic liquids (PILs) containing various carboxylate anions for CO2 capture for post-combustion method. The PILs were synthesized using a straightforward process, and the behavior of their CO2 absorption was investigated in relation to the alkyl chain of odd and even chain anions. The PILs were characterized using 1H NMR, 13C NMR, and HRMS techniques. The study results indicate that ED-ILs with longer alkyl chains are better at absorbing CO2. Among all the PILs, [ED][Hep] exhibited the highest absorption capacity except [ED][But], absorbing 0.26 CO2/mol of IL at 298K and 0.1 MPa. The thermophysical properties, including density, sound speed, viscosity, and refractive index of neat ED-based PILs, were tested at different temperatures and 0.1 MPa. Furthermore, the derived parameters such as expansion coefficient (α), molecular volume (V), isentropic compressibility (βs), lattice potential energy (UPOT), standard entropy (S0), Intermolecular free length (Lf) and free volume (Vm) were determined using experimental parameters. It was shown that these characteristics were directly related to the PILs ability to absorb CO2. Overall, the investigation demonstrated that [ED][But] offers a great potential for utilization as a CO2 absorption solvent because of its high absorption capacity and special qualities as a PIL.

The generation of thioesters through thioesterification of carboxylic acid has significant synthetic value given the easy availability of various carboxylic acids and the extensive application of thioesters. An economical and rapid thioester synthesis approach is still needed. Herein, we achieved thioesterification of carboxylic acids with valuable glycosyl thiol, aromatic and aliphatic thiols mediated by sulfonyl fluoride (SO2F2). The compatibility of numerous carboxylic acid substrates was tested, including (hetero)aromatic and aliphatic carboxylic acids and the reaction proceeded smoothly under mild conditions at good yields. Late‐stage modification of drug molecules rac‐Naproxen and Loxoprofen proved feasible. Besides, the gram‐scale reaction demonstrated the utility of this protocol. [ABSTRACT FROM AUTHOR]

BODIPY based molecules functionalized with water soluble moieties have been developed and recognized as liable triplet photosensitizers for phototherapeutic applications. In this work, we have prepared BODIPY analogues with dicarboxylic acid groups and bearing iodine or fullerene moieties for efficient intersystem crossing which display far‐red absorption band and high singlet oxygen production both in organic and aqueous media. In this perspective by using similar design the effect of the halogenation of the dyes versus spin converter on the skeleton were compared. The structures of the synthesized BODIPYs and BODIPY‐C60 (6–10) were elucidated by mass, 1H and 13C NMR spectroscopic techniques. Photophysical and photochemical properties of the compounds were examined using UV‐Vis. absorption and fluorescence emission spectrophotometers. The absorption intensities of the trap molecules (DPBF and ADBA) reduced because of singlet oxygen generation in the media. This study may provide useful infrastructure to elucidate the relationship between the use of fullerene (9) or iodine (10) where singlet oxygen quantum yield of 9 and 10 are determined as 0.87 and 0.97 respectively. [ABSTRACT FROM AUTHOR]

Electrochemical hydrogenations are considered a sustainable alternative to classical thermocatalytic processes prevalent in industrial conversions. Using a base metal sulfide of the pentlandite class, the hydrogenation of glutaraldehyde and propionic acid was investigated. While propionic acid could not be converted, glutaraldehyde was conveniently transformed to the semi‐ and fully hydrogenated products 5‐hydroxypentanal and 1,5‐pentanediol with a partial current density of up to 34 mA cm−2 and a Faraday efficiency of 34 %. Crucial factors for a stable and efficient reaction were found to be the use of an appropriate buffer, avoidance of low pH and the used membrane type. The reaction was implemented into a zero‐gap cell reaching a single pass conversion of up to 22 %, underlining the potential for future application. [ABSTRACT FROM AUTHOR]

Soil alkalization is an important environmental factor limiting crop production. Despite the importance of root secretion in the response of plants to alkali stress, the regulatory mechanism is unclear. In this study, we applied a widely targeted metabolomics approach using a local MS/MS data library constructed with authentic standards to identify and quantify root exudates of wheat under salt and alkali stresses. The regulatory mechanism of root secretion in alkali-stressed wheat plants was analyzed by determining transcriptional and metabolic responses. Our primary focus was alkali stress-induced secreted metabolites (AISMs) that showed a higher secretion rate in alkali-stressed plants than in control and salt-stressed plants. This secretion was mainly induced by high-pH stress. We discovered 55 AISMs containing –COOH groups, including 23 fatty acids, 4 amino acids, 1 amino acid derivative, 7 dipeptides, 5 organic acids, 9 phenolic acids, and 6 others. In the roots, we also discovered 29 metabolites with higher levels under alkali stress than under control and salt stress conditions, including 2 fatty acids, 3 amino acid derivatives, 1 dipeptide, 2 organic acids, and 11 phenolic acids. These alkali stress-induced accumulated carboxylic acids may support continuous root secretion during the response of wheat plants to alkali stress. In the roots, RNAseq analysis indicated that 5 6-phosphofructokinase (glycolysis rate-limiting enzyme) genes, 16 key fatty acid synthesis genes, and 122 phenolic acid synthesis genes have higher expression levels under alkali stress than under control and salt stress conditions. We propose that the secretion of multiple types of metabolites with a –COOH group is an important pH regulation strategy for alkali-stressed wheat plants. Enhanced glycolysis, fatty acid synthesis, and phenolic acid synthesis will provide more energy and substrates for root secretion during the response of wheat to alkali stress. [ABSTRACT FROM AUTHOR]

In the present study, the effectiveness of catalytic wet oxidation triggered by using Cu-Ce/γ-Al2O3 to degrade antibiotic excess sludge was investigated, during which some small molecule carboxylic acids were produced, which are valuable in biological wastewater treatment as an organic carbon source. The influence of reaction parameters on the degradation efficiency was explored through single-factor and orthogonal experiments, including catalyst amount, reaction temperature and time, and oxygen supply amount. The results illustrated that the treatment system can achieve 81.2% COD and 93.8% VSS removal rates under optimized reaction conditions. Carboxylic acids produced after the sludge degradation mainly included acetic acid, propanoic acid, etc. The results of wastewater biological treatment experiments exhibited that the degraded solution after catalytic wet oxidation has potential to be used as a carbon source to meet the demand of biological treatment, which helps the removal of COD and TN. This work confirms the effectiveness of catalyst for enhancing antibiotic excess sludge treatment, which provided a new idea for the rational disposal of antibiotic excess sludge. [ABSTRACT FROM AUTHOR]

Here we report the challenging O‐trifluoromethylation of carboxylic acids via the formation and activation of acyloxy(phenyl)trifluoromethyl‐λ3‐iodanes. The method provides an easy access to various potentially valuable and hitherto elusive trifluoromethyl carboxylic esters. A remarkably wide range of substrates with commonly encountered functional groups are compatible with this reaction, including aromatic and aliphatic carboxylic acids, as well as Food and Drug Administration (FDA) approved drugs and pharmaceutically relevant molecules. The reaction mechanism and the origins of the enhanced reactivity by zinc chloride (ZnCl2) were discussed from experimental evidence and density functional theory (DFT) calculation. [ABSTRACT FROM AUTHOR]

Pyridine‐borane complex was widely used as a reducing agent, but the exploration of such reagent as a catalyst for amidation of carboxylic acids are still unknown. Here we reported the first example of direct amidation of carboxylic acids catalyzed by pyridine‐borane complexes. This protocol features a low catalyst loading (0.2–10 mol %), broad substrate scope, good functional group compatibility, and affording the amides in high yields. [ABSTRACT FROM AUTHOR]

A new electrochemical transformation is presented that enables chemists to couple simple alkyl carboxylic acid derivatives with an electrophilic amine reagent to construct C(sp3)−N bond. The success of this reaction hinges on the merging of cooperative electrochemical reduction with nickel catalysis. The chemistry exhibits a high degree of practicality, showcasing its wide applicability with 1°, 2°, 3° carboxylic acids and remarkable compatibility with diverse functional groups, even in the realm of late‐stage functionalization. Furthermore, extensive mechanistic studies have unveiled the engagement of alkyl radicals and iminyl radicals; and elucidated the multifaceted roles played by iPr2O, Ni catalyst, and electricity. [ABSTRACT FROM AUTHOR]

Zeta potential is an important colloid parameter that dictates many intriguing phenomena such as colloid stability/aggregation, electrophoretic deposition and particle separation technology. Zeta potential is commonly used to characterise colloid particles' electrostatic interactions coupled with other forces such as van der Waals attraction, hydration and steric forces. However, the measurement of zeta potential involves complicated sample preparation and instrument/theory selection, often resulting in inaccurate measurement. Here, we developed a simple method that combines Stern–Grahame and Gouy–Chapman theories, for estimating zeta potential using parameters such as acid site pKa, acid site density and particle size. The method is applied to a wide range of carboxylic acids' functionalised colloid particles with various pKa. Results show that the new method is capable of capturing zeta potential dependence on pKa and pH. The new method can be applied to particles with complicated or multiple acid/base sites. Without the need for sample preparation/instrument, this new method is believed to save efforts for estimating zeta potential with good accuracy. [ABSTRACT FROM AUTHOR]

The selection of a "perfect tool" for the theoretical determination of acid-base dissociation constants (Ka) is still puzzling. Recently, we developed a user-friendly model exploiting CAM-B3LYP for determining pKa with impressive reliability. Herein, a new challenge is faced, examining a panel of functionals belonging to different rungs of the "Jacob's ladder" organization, which classifies functionals according to their level of theory. Specifically, meta-generalized gradient approximations (GGAs), hybrid-GGAs, and the more complex range-separated hybrid (RSH)-GGAs were investigated in predicting the pKa of differently substituted carboxylic acids. Therefore, CAM-B3LYP, WB97XD, B3PW91, PBE1PBE, PBEPBE and TPSSTPSS were used, with 6-311G+(d,p) as the basis set and the solvation model based on density (SMD). CAM-B3LYP showed the lowest mean absolute error value (MAE = 0.23) with relatively high processing time. PBE1PBE and B3PW91 provided satisfactory predictions (MAE = 0.34 and 0.38, respectively) with moderate computational time cost, while PBEPBE, TPSSTPSS and WB97XD led to unreliable results (MAE > 1). These findings validate the reliability of our model in predicting carboxylic acids pKa, with MAE well below 0.5 units, using a simplistic theoretical level and a low-cost computational approach. [ABSTRACT FROM AUTHOR]

During recrystallization from benzene or toluene of the products of interaction of triarylantimony or triarylbismuth with carboxylic acids, phenol, or oxime in the presence of tert-butyl hydroperoxide (molar ratio 1 : 2 : 1, diethyl ether, 24°C, 24 h), minor products, adducts of aryl compounds of antimony or bismuth of the Ar3MX2 type with carboxylic acids, phenol, and oxime are isolated. According to X-ray structural analysis conducted at 293 K using an automatic D8 Quest Bruker four-circle diffractometer (two-coordinate CCD detector, Mo Kα radiation, λ = 0.71073 Å, graphite monochromator), the metal atoms in the crystals of m-Tol3Sb[OC(O)C6H3F2-2,5]2 ⋅ HOC(O)C6H3F2-2,5 (1) [C42H31O6F6Sb, M 867.42; triclinic system, symmetry group P ; cell parameters a = 8.78(5) Å, b = 13.10(6) Å, c = 16.64(8) Å; α = 102.86(19)°, β = 99.3(2)°, γ = 98.0(3)°; V = 1813(16) Å3; Z 2; reflection index intervals –7 ≤ h ≤ 7, –11 ≤ k ≤ 11, –14 ≤ l ≤ 14; total reflections 14 149; independent reflections 2603; Rint 0.0284; GOOF 1.049; R1 = 0.0348, wR2 = 0.0938; residual electron density 0.55/–0.42 e/Å3], p‑Tol3Bi[OC(O)C6HF4-3,4,5,6]2 ⋅ HOC(O)C6HF4-3,4,5,6 (2) [C42H25O6F12Bi, M 1062.60; triclinic system, symmetry group P ; cell parameters a = 12.246(11) Å, b = 12.976(18) Å, c = 14.391(13) Å; α = 68.27(4)°, β = 69.89(3)°, γ = 86.11(5)°; V = 1990(4) Å3; Z 2; reflection index intervals –15 ≤ h ≤ 15, ‒16 ≤ k ≤ 16, –18 ≤ l ≤ 18; total reflections 48 542; independent reflections 9207; Rint 0.0321; GOOF 1.136; R1 = 0.0322, wR2 = 0.0648; residual electron density 1.81/–1.08 e/Å3], [(2-MeO-5-BrC6H3)3SbOC6H4Br-4]2O ⋅ 2HOC6H4Br-4 (3) [C66H54Br10O11Sb2, M 2065.69; monoclinic system, symmetry group C21/c; cell parameters a = 12.017(14) Å, b = 25.54(3) Å, c = 13.181(18) Å; β = 116.71(5)°; V = 3613(8) Å3; Z 2; reflection index intervals –13 ≤ h ≤ 13, –27 ≤ k ≤ 27, –12 ≤ l ≤ 12; total reflections 29 461; independent reflections 4545; Rint 0.0656; GOOF 1.062; R1 = 0.0565, wR2 = 0.1200; residual electron density 1.59/–1.31 e/Å3], and [(2-MeO)C6H4]3Sb[ON=CHC4H2(NO2-2)]2 ∙ 2HON=CHC4H2(NO2-2) ∙ 1/2PhH (4) [C44H38N8O19Sb, M 1104.57; triclinic system, symmetry group P ; cell parameters a = 10.240(5) Å, b = 14.480(8) Å, c = 18.093(11) Å; α = 103.43(3)°, β = 104.50(2)°, γ = 98.876(17)°; V = 2461(2) Å3; Z 2; reflection index intervals –13 ≤ h ≤ 13, –18 ≤ k ≤ 18, –23 ≤ l ≤ 23; total reflections 58 643; independent reflections 10 886; Rint 0.0558; GOOF 1.061; R1 = 0.0429, wR2 = 0.1095; residual electron density 1.91/–0.51 e/Å3] show distorted trigonal-bipyramidal coordination with oxygen atoms in axial positions. Full tables of atom coordinates, bond lengths, and valence angles for the structures are deposited in the Cambridge Structural Database (no. 2050322 for 1, no. 2045173 for 2, no. 2070387 for 3, and no. 2119790 for 4; deposit@ccdc.cam.ac.uk; https://www.ccdc.cam.ac.uk). [ABSTRACT FROM AUTHOR]

Biomass, as the exclusive and abundant organic resources, is considered to be the promising renewable resource. Carboxylic acids are one of the many compounds that can be obtained from raw biomass. Decarboxylation of carboxylic acids into fuels and chemicals via electrochemical method at mild reaction condition has been studied for many years. The (non-)Kolbe reaction, one of the oldest organic electrochemical reactions, is the decarboxylation of carboxylic acids to produce alkanes, alcohols, esters, etc. And electrode materials influence the production of electrocatalytic decarboxylation products from carboxylic acids. Therefore, this work mainly reviews the recent advances in applications of anodic materials for (non-)Kolbe electrocatalytic decarboxylation of carboxylic acids. It discusses the reaction mechanism of (non-) Kolbe electrolytic reaction, and the electrocatalytic oxidation of carboxylic acid using different electrodes and electrolytic systems to synthesize fuels and chemicals. Also, various types of electrode catalysts, such as Pt-based catalysts, C-based catalysts, and other catalysts, are introduced in detail. Finally, the challenges and future trends of the (non-)Kolbe reaction of carboxylic acids are presented. This review found that platinum-based electrocatalysts proved to be the most promising catalysts at present. And in recent years, a variety of synthesis methods have been developed to synthesize small size and high-performance noble metal based amorphous catalysts. Another approach is to study catalysts without platinum electricity, such as Ru, Ir, Ti and carbon materials. The review is helpful in understanding and know the anodic materials and their application in (non-)Kolbe electrocatalytic decarboxylation of carboxylic acids for the readers.

The advancement of sustainable photoredox catalysis in synthetic organic chemistry has evolved immensely because of the development of versatile and cost‐effective reagents. In recent years, a substantial effort has been dedicated to exploring the utility of formic acid salts in various photochemical reactions. In this context, formates have demonstrated diverse capabilities, functioning as reductants, sources of carbonyl groups, and reagents for hydrogen atom transfer. Notably, the CO2⋅– radical anion derived from formate exhibits strong reductant properties for cleaving both C−X and C−O bonds. Moreover, these salts play a pivotal role in carboxylation reactions, further highlighting their significance in a variety of photochemical transformations. The ability of formates to serve as reductants, carbonyl sources, and hydrogen atom transfer reagents reveal exciting possibilities in synthetic organic chemistry. This minireview highlights an array of captivating discoveries, underscoring the crucial role of formates in diverse and distinctive photochemical methods, enabling access to a wide range of value‐added compounds. [ABSTRACT FROM AUTHOR]

In pKa computational determination, the challenge in exploring and fostering new methodologies and approaches goes in parallel with the amelioration of computational performances. In this paper a "ready to use methodology" has been compared to other strategies, such as the re‐shaping in solvation cavity (Bondi radius re‐shaping), wanting to assess its reliability in predicting the pKa of a broad list of carboxylic acids. Thus, the functionals B3LYP and CAM‐B3LYP have been selected, using SMD as continuum solvation model. Exploiting our previous results, two water molecules were made explicit on the reaction centre. Data show that our model (CAM‐B3LYP/2H2O) is capable to accurately predict pKa, leading to mean absolute error (MAE) values lower than 0.5. Noteworthy, good results were achieved in computing the pKa of substituents bearing nitro and cyano groups. Focusing on B3LYP, eventually remarkable outputs were obtained only when Bondi correction was applied to the complex with two water molecules. Hence, massive outcomes were obtained in foreseeing the trichloro and trifluoro acetic acid pKa. These findings demonstrated that no complex level of theory nor external factor is required to accurately predict carboxylic acids pKa, with MAE well below 0.5 units. [ABSTRACT FROM AUTHOR]

This document provides a series of chemical reactions and their corresponding products, specifically focusing on the synthesis of various urea compounds starting from different acids. The authors provide detailed experimental procedures and characterization data, including NMR spectra, melting points, and yields for each compound. The compounds synthesized include ureas and triazoles, and the data presented can be valuable for researchers studying the synthesis and characterization of these compounds. [Extracted from the article]

This study employs computational simulations to comprehensively investigate the molecular properties of 1,4-Dinitrosopiperazine-2-carboxylic acid. Through rigorous analysis, the research explores the compound's structural characteristics, vibrational assignments, chemical shifts, electronic properties, donor-acceptor interactions, Mulliken atomic charges, molecular electrostatic potential surface (MESP), and thermodynamic parameters. The findings provide intricate insights into the behavior of the compound, unveiling potential applications in diverse chemical contexts. This thorough examination contributes significantly to our understanding of the fundamental properties of 1,4-Dinitrosopiperazine-2-carboxylic acid, offering invaluable knowledge for both further research endeavors and practical applications. The detailed elucidation of these properties holds promise for advancements in various fields, from pharmaceuticals to materials science, marking a significant stride towards harnessing the full potential of this compound in contemporary chemistry. [ABSTRACT FROM AUTHOR]

Nanotechnology is playing a significant role in modern life with tremendous potential and promising results in almost every domain, especially the pharmaceutical one. The impressive performance of nanomaterials is shaping the future of science and revolutionizing the traditional concepts of industry and research. Titanate nanotubes (TNTs) are one of these novel entities that became an appropriate choice to apply in several platforms due to their remarkable properties such as preparation simplicity, high stability, good biocompatibility, affordability and low toxicity. Surface modification of these nanotubes is also promoting their superior characters and contributing more to the enhancement of their performance. In this research work, an attempt was made to functionalize the surface of titanate nanotubes with carboxylic groups to increase their surface reactivity and widen the possibility of bonding different molecules that could not be bonded directly. Three carboxylic acids were investigated (trichloroacetic acid, citric acid and acrylic acid), and the prepared composites were examined using FT-IR and Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The toxicity of these functionalized TNTs was also investigated using adherent cancer cell lines and fibroblasts to determine their safety profile and to draw the basic lines for their intended future application. Based on the experimental results, acrylic acid could be the suitable choice for permanent surface modification with multiple carboxylic groups due to its possibility to be polymerized, thus presenting the opportunity to link additional molecules of interest such as polyethylene glycol (PEG) and/or other molecules at the same time. [ABSTRACT FROM AUTHOR]

New N-heterocylic, homocyclic and aliphatic dronic acids were synthesized through an improved facile and versatile route by the reaction of various carboxylic acids with Phosphorus trichloride (PC), phosphorus acid (PA) and methanesulfonic acid under reflux and inert atmosphere. Representatively, the dronic acid derived from stearic acid as a long chained fatty acid was also synthesized. All the obtained compounds were analyzed and characterized by means of FT IR, 1H, 13C and 31P NMR spectroscopic techniques. In addition, the compound derived from stearic acid was characterized by means of FT IR and Mass spectrometry due to its insolubility in D2O and DMSO-d6. [ABSTRACT FROM AUTHOR]