Acids - Science topic

In this work, the possibility of lugduname and perillartin electrochemical determination by cathodic process has been given. Both substances are reduced, forming the amino group, which may become protonated in an acidic medium, affecting the DEL ionic force and thereby affecting the analytical signal interpretation. Although even in the acidic medi...

The possibility of sucralose and lugduname electrochemical determination in beverages has been analyzed for the first time from a theoretical point of view. It has been shown that the electrochemical determination of sucralose and lugduname may be carried out efficiently by an anodic process due to the presence of electroactive groups in both subst...

Herein, a new two‐dimensional (2D) Ce‐organic frameworks (referred to as SLX‐4) was achieved by traditional solvothermal conditions. Initial studies of SLX‐4 toward Hantzsch reaction showed that good catalytic activity can be obtained under mild conditions, giving the desired 1,4‐dihydropyridines in moderate to high yields. The catalyst could be re...

Siderite (FeCO 3 ) is an important reservoir of mineral-bound ferrous iron in non-sulfidic, reducing soils and sediments. It is redox sensitive, and its oxidation may facilitate the reduction of a range...

Objective Neural tube defects (NTDs) are serious, life-threatening birth defects. Staple food fortification with folic acid (vitamin B9) is a proven, effective intervention to reduce NTD birth prevalence. Mandatory food fortification with folic acid was implemented in South Africa (SA) in 2003. This article provides an overview of NTD birth prevale...

The energy conversion efficiency of a carbon black-phosphoric acid composite ultracapacitor was determined. A typical ultracapacitor had a maximum energy storage capacity of 24.32J. It had a specific energy of 8.11 J/g of which, during discharge, 36% was dissipated internally in the ultracapacitor, in two resistances of 2.66Ω and 54.01Ω, where the...

In the title compound, 2C7H7N2O+·C2O42 , proton transfer from oxalic acid to the N atom of the heterocycle has occurred to form a 2:1 molecular salt. In the extended structure, N—H� � �O hydrogen bonds link the components into [100] chains, which feature R22(8) and R4 4(14) loops.

A convenient method for the N‐modification of NH‐tetrazoles by the Rh(II)‐catalyzed insertion reaction of diazocarbonyl compounds into the N−H bond has been proposed. A wide range of structurally diverse diazo reagents (including heterocyclic ones) as well as tetrazoles with different substituents in the fifth position have been used to prepare 2,5...

This study aimed to investigate whether beta-alanine supplementation (BA) improves performance and rating of perceived exertion (RPE) and reduces the respiratory exchange ratio (RER) during a CrossFit® workout. Fourteen participants were randomized in a double-blind design to either BA or placebo, with 12 participants (7 males, 5 females, 32 ± 9.2...

Microplastic (MPs) pollution has became a serious issue. Photoaging is one of the main ways to produce MPs. Polylactic acid (PLA) is the most commonly used biodegradable plastic in industry, however, the current reports on the quantitative data of biodegradable PLA MPs produced by photoaging were little known. Therefore, this study selected PLA MPs...

The N−H insertion reaction is a versatile method for creating C−N bonds under mild conditions, providing in particular an efficient access to both natural and non‐natural α‐amino acid derivatives. In this field, the direct N−H insertion on α‐diazo‐β‐hydroxyesters has not yet been investigated and constitutes a significant challenge, due to competit...

We propose SelfSplat, a novel 3D Gaussian Splatting model designed to perform pose-free and 3D prior-free generalizable 3D reconstruction from unposed multi-view images. These settings are inherently ill-posed due to the lack of ground-truth data, learned geometric information, and the need to achieve accurate 3D reconstruction without finetuning,...

Fully substituted divinyl ketones (fsDVKs) have long been regarded as resistant to Nazarov cyclization (NC) unless they contain strategically positioned electronically activating substituents. Here, however, we show that fsDVKs bearing only electronically neutral alkyl or aryl groups actually undergo facile NC due to steric crowding in the pentadie...

Despite the numerous published syntheses and applications of sulfoximines, very few studies describe their physico‐chemical properties and in particular their acidic, basic and lipophilic or hydrophilic characters. We report for the first time the acidity values (pKa) of fluorinated sulfoximines in water and in acetonitrile, as well as the basicity...

Carbonyl‐bearing furans, certain pyrroles, and thiophenes were alkylated using alcohols in an acidic medium. Some 5‐alkylated derivatives of 2‐furoic acid with various adamantyls‐, cycloalkyl‐, other 2°‐ and 3°‐alkyl substituents were synthesized using 2‐furoic acid as a biomass‐derived chemical platform. Side reaction resulted in the substitution...

Chromone-3-carbonitrile has been extensively studied in a panel of high-value transformations. However, existing protocols for the synthesis of this scaffold are often constrained by the structure of the starting materials and harsh conditions. To address these issues, we present a novel strategy that HFIP (hexafluoroisopropanol)-driven strategy, e...

The current research aimed to study and measure the solubility of omeprazole (used to treat and reduce stomach acid) for the first time in pure subcritical and ethanol-modified water. These tests have been performed in the 25–130 °C temperature range and constant pressure of 20 bar with the use of 0–10% ethanol weight as the cosolvent. The solubili...

Moisture stress on soil nutrient in acid soil

This review article discusses and summarizes the synthesis and applications of luminescent metal–organic frameworks (MOFs) for sensing dipicolinic acid in biological and water samples.

A divergent total synthesis of bioactive, naturally occurring decanolides, pinolidoxin and bellidisin C, was accomplished by taking advantage of chiral templates L-ribose and L-malic acid. In particular, bellidisin C, which is the first total synthesis so far, was achieved through a cascade reaction of reductive elimination and nucleophilic additio...

A method to form a UV-Visible active derivative of Salicylic acid was developed. The method was based on the reaction of salicylic acid, forming a colored derivative, which was UV-Visible active. The method was used to analyze pharmaceutical dosage form for trace amount of salicylic acid using UV-Visible spectrophotometer. The formed derivative exh...

Over the past years, enzymatic depolymerization of PET, one of the most widely used plastics worldwide, has become very efficient leading to the end products terephthalic acid (TPA) and ethylene glycol (EG) used for PET re‐synthesis. Potent alternatives to these monomers are the intermediates BHET and MHET, the mono‐ and di‐esters of TPA and EG whi...

In this paper, tartaric acid (C4H6O6) was used as a reductant to treat chromium (VI)-containing solution. Several independent experimental parameters, including reaction temperature, concentration of H2SO4, concentration of C4H6O6 and reaction time, on the reduction process were studied. The results showed that 100% of the Cr (VI) could be reduced...

A stepwise copper‐catalyzed boracarboxylation then palladium‐catalyzed Suzuki‐Miyaura cross‐coupling methodology was developed to access 2,3‐diarylpropionic acid derivatives regioselectively by pre‐setting the position of the carboxylic acid in the boracarboxylation reaction. This method provides access to a wide range of aryl and heteroaryl produc...

The changes in the crystal structure of the W−V‐Nb complex oxide with phosphorus addition to the hydrothermal synthesis process are investigated. The effect of the constituent units and crystal structure of phosphorus‐added W−V‐Nb complex oxide catalysts on the activity and selectivity for selective oxidation of acrolein is discussed. Phosphorus ad...

Correction for ‘A safe and efficient synthesis of N-Boc-β³-amino acid methyl esters from α-amino acids: applications in the formal synthesis of sedum alkaloids’ by Bohua Long et al., RSC Adv., 2024, 14, 36016–36021, https://doi.org/10.1039/D4RA07506D.

A group of new zwitterion based ionic liquid crystals (ILCs) has been synthesized. Depending on the counter anion (mesylate or hydrogen sulfate) the phase behavior of the resulting ILCs is...

The title compound, trans-11-(3,4-Dimethoxyphenyl)-2,3,8,9-tetramethoxy-6-oxo-11,12-dihydro-6H-dibenzo[c,h]chromene-12-carboxylic acid (4), was synthesized for the first time via a two-step protocol from 3,4-dimethoxyhomophthalic anhydride (1) and 3,4-dimethoxybenzaldehyde (DMBA). In the first step, 1 reacts with DMBA to give trans-3-(3,4-dimethoxy...

Asymmetric de novo synthesis of benzocyclobutenes (BCBs) via catalytic intermolecular reaction is highly desired for efficient access to this important class of compounds, yet such a strategy remains unmet challenge. Here, we report a Pd/Pyrox‐catalyzed asymmetric [2+2] annulation between arylboronic acids and functionalized alkenes, providing an u...

В нескольких исследованиях была продемонстрирована кардиотропная активность производного малоновой кислоты — этмабена, возможность применения эмпаглифлозина при хронической сердечной недостаточности доказана рядом доклинических и клинических исследований. Авторы провели сравнительную оценку эффективности препаратов в схемах монотерапии и комбиниров...

The obtained results reveal simple synthetic approach for bidentate boron Lewis acids with the ‐OB(C6F5)2 acid group and aliphatic or aromatic linkers. Computational results showed comparable FIA for the ‐OB(C6F5)2 site in boron bidentate Lewis acids relative to initial B(C6F5)3. The relative Lewis acid strength of R[OB(C6F5)2]2 (R=C2H4, p‐C6H4, m‐...

The quinoline-based tripodal fluororeceptor 1 has been designed and synthesized for the detection of citric acid in less polar solvents. Receptor 1 shows monomer emission quenching followed by excimer emission upon hydrogen bond-mediated complexation of citric acid. In comparison, receptor 2, in presence of the same acid, gives rise to a decrease i...

We report a catalytic late‐stage bromination strategy for the α‐C−H functionalization of aryl acetic acid. The aryl acetic acid was transformed into enediolate in the presence of an (AcO)4B2O with the combination of DBU, and consequently underwent an electrophilic bromination reaction with pyridinium tribromide. A wide range of α‐bromo aryl acetic...

A medicina antienvelhecimento tem como foco melhorar a qualidade de vida durante o envelhecimento, levando em consideração a influência de fatores ambientais como poluição, tabaco, dieta inadequada, estresse e sono irregular. Os produtos cosméticos antienvelhecimento, especialmente os que contêm ácido retinóico, têm se destacado por suas propriedad...

A chitosan-supported CuI (CS@CuI) catalyst was developed for the synthesis of quinazolinones from 2-halobenzoic acids (including iodine and bromine) and amidines. The reaction proceeds under mild reaction conditions, demonstrating a broad substrate scope (30 examples) and good catalytic efficiency (up to 99% yield).

We report sulfonated hypercrosslinked polymers (SHCPs) as heterogeneous catalysts for the selective esterification of hexanoic acid with benzyl alcohol. The SHCPs demonstrate tuneable catalytic activity and selectivity, outperforming conventional acid...

Despite extensive efforts to develop γ‐lactamization reactions for pyrrolidinone synthesis using either cyclometallation, C−H insertion, or radical C−H abstraction strategies, γ‐lactamization reactions of aliphatic amides using practical catalysts and common protecting groups remain extremely rare. Herein we report copper‐catalyzed γ‐C(sp³)−H lacta...

Eragrostis tef is a small annual cereal crop that naturally produces many tillers. In the past, there has been a focus on selecting for high tillering. However, having many tillers can negatively impact grain size, increase lodging, and result in uneven grain maturation. This study aimed to investigate the effectiveness of using plant growth regula...

Alkylphenyl imidazolines with phenyl (PHI), 4-methylphenyl (TI) and 4-isopropoxyphenyl (IPRI) substituents were synthesized and their properties in slowing down the corrosion of 08PS low-carbon steel have been studied in 2 M HCl, 2 M H 2 SO 4 and 2 M H 3 PO 4 (t=25-95 C). It has been demonstrated that for the protection of steel in mineral acid sol...

The steel ball, as a key rolling element in mechanical equipment, directly affects the performance and service life of the bearing through its surface quality. Traditional methods for detecting surface defects on steel balls often face challenges in efficiency and stability. They struggle with three-dimensional surfaces and are easily affected by n...

The present work reports on the production of di-isoamyl ether from the etherification of isoamyl alcohol, using the sulphonic resin Amberlyst®-15 (A-15) as a catalyst. Parameters such as temperature, reaction time and amount of catalyst were studied. Although the etherification reaction shows low conversions (9-18%), when glycerol is added to the...

thường được sử dụng ăn tươi hoặc sản phẩm chế biến như nước dứa ép, nước dứa cô đặc, dứa sấy… Hiện nay, sản phẩm mứt nhuyễn từ dứa chưa phổ biến trên thị trường và chưa có nghiên cứu đầy đủ về công nghệ chế biến sản phẩm này. Mục đích của nghiên cứu này nhằm xác định được một số thông số công nghệ bao gồm tỷ lệ phối trộn nước cốt dừa, hàm lượng aci...

C 7 H 3 ClF 3 NO 2 , triclinic, P 1 ‾ $P\overline{1}$ (no. 2), a = 5.8837(5) Å, b = 14.1634(14) Å, c = 15.3120(15) Å, α = 92.667(5)°, β = 100.364(5)°, γ = 99.475(5)°, V = 1,234.2(2) Å ³ , Z = 6, R gt ( F ) = 0.0458, wR ref ( F ² ) = 0.1012, T = 298 K.

A modular, 3‐steps protocol for the synthesis of N‐sulfonyl squaramides has been developed. The strategic installation of a tetrahedral, electron‐withdrawing sulfonyl group into the squaramido core allowed the prevention of undesired self‐aggregations, therefore upgrading the solubility in common organic solvents, and moreover, enhancing their H‐bo...

It gives an insightful approach to the concept of pH, Acids and bases. The fundamental concept of acid and alkaline solutions, relationship between acids and bases, their pH of the various regions in the body, pH in disease and disorders and the application of pH in pharmacy, medicine and other fields.

Reliable radical precursors are crucial for photocatalytic processes. In particular, heteroatom‐stabilized radicals have attracted considerable research interest in photocatalysis. Among them, α‐amino radicals have received the most attention, while the research on α‐hydroxy radicals is much less developed. Herein, we present O‐PMP α‐hydroxycarboxy...

A diaminomethylenemalononitrile organocatalyst efficiently promoted the asymmetric conjugate addition of cyclic β‐keto esters to (E)‐β‐nitroacrylate derivatives, yielding the corresponding β‐nitro esters derivatives with excellent enantioselectivities (up to >99 % ee). This is the first successful example of highly stereoselective conjugate additio...

β³-Amino acids are essential components in the synthesis of biologically active compounds. However, obtaining them in enantiomerically pure forms remains challenging. This study investigates a safe and efficient method for synthesizing enantiopure N-Boc-β³-amino acid methyl esters, incorporating both natural and unnatural side chains. The procedure...

(−)-Pleurotin (1) and (+)-dihydropleurotinic acid (2) are benzoquinone meroterpenoids isolated from fungal sources with powerful antitumor and antibiotic activities. Concise asymmetric total syntheses of the stereochemically pure (+)-dihydropleurotinic acid (2) and (−)-pleurotin (1) from the chiral pool (R)-Roche ester-derived vinyl bromide 7 have...