Search

Reduction of carboxamides is an efficient approach to obtain the corresponding amines, albeit it is one of the most problematic. In this work, by use of pinacolborane (HBpin) as a reductant, the rare‐earth metal tris (arylamido) complex supported by a ferrocenyl‐modified arylamido ligand La[NH‐2,6‐iPr2‐4‐FcC6H2]3 was employed as a precatalyst for primary and secondary amide reductions. This catalyst system exhibited high activity toward hydroborative reduction of amides to amines under mild conditions, as well good tolerance for heteroatoms and functional groups in the reduction. A lanthanide hydride was experimentally verified as the active species and the reduction mechanism was proposed. [ABSTRACT FROM AUTHOR]

A novel metal‐organic frameworks (MOF) material, namely {Zn3(bpybc)(imdc)2·H2O)}n (1), (bpybc2− = 1,1′‐bis(4‐carboxyphenyl)‐4,4′ ‐bipyridinium cation, imdc3− = 4,5‐imidazole‐dicarboxylic acid anion) has been successfully synthesized under solvothermal conditions. The synthesis utilized H2bpybc·2Cl, 4,5‐imidazole‐dicarboxylic acid and Zn(NO3)2·6H2O as the raw materials. Complex 1 not only exhibits reversible photochromic behavior but also features photocontrolled luminescence properties. Notably, complex 1 shows the sensing ability of Cr2O72−. It has the capability to selectively detect ammonia vapor, undergoing a color change from orange to tan in response to ammonia vapors, thereby exhibiting certain sensing properties for ammonia vapor. [ABSTRACT FROM AUTHOR]

The complexes [RuCl(Cy)(NH2Ph)2]Cl (1), [RuCl2(Cy)(NH2Bz)] (2), and [RuCl2(Cy)(NHBz2)] (3) were synthesized under identical conditions from [RuCl2(Cy)]2, where Cy=η6‐p‐cymene, Ph=phenyl, and Bz=benzyl. X‐ray crystallography revealed an additional NH2Ph ligand in 1, distinguishing it from the neutral mono‐amine complexes 2 and 3. The number of amines in these complexes did not correlate clearly with the σ‐donor character or steric hindrance of the amines. Different reactivities were observed for the ROMP of norbornene (NBE), as measured by batch reactions and kinetic studies using Raman and 1H NMR spectroscopy. Semiquantitative conversions reached up to 90 % with complex 1 and around 40 % with complexes 2 and 3. DFT calculations supported the hypothesis that the reaction for complex 1 involves the release of an amine through a dissociative mechanism, whereas complexes 2 and 3 react through an associative mechanism involving amine loss. The presence of an amine in the propagation species of complex 1 suggests the participation of the amine as an ancillary ligand. All carbene species are of the η2‐p‐cymene type, and the catalytic cycle follows a 14–16‐14 electron counting mechanism. [ABSTRACT FROM AUTHOR]

The chemistry of bidentate ligands with a dppf-like motif, where phosphorus is fully or partially replaced by other pnictogens as donor sites, is summarized and discussed in this comprehensive review, while covering the literature from 1966 to 2024, related to more than 165 original references and discussing more than 75 independent chemical entities (1–41). Besides addressing synthetic, structural, and electrochemical aspects of such compounds, their donor properties and metal coordination behavior is discussed, along with catalytic applications. Based on their electronic and steric situations, trends in the performance of such compounds, either as ligands for catalysis or on their own merits for non-catalytic purposes, have been elucidated. Related topics that could not be covered in this article have been acknowledged by referring to the literature for completeness. [ABSTRACT FROM AUTHOR]

New amino-derivatives of 3-oxo-24-nor-allobetulin (3-semicarbazone, 1,2,3-thiadiazole, 3β-amine, methoxylactam) were synthesized. The structures of the 3E-oxime and 3E-methoxyoxime of 24-nor-allobetulin were confirmed by X-ray crystal structure analyses. [ABSTRACT FROM AUTHOR]

Purine stretches, sequences of adenine (A) and guanine (G) in DNA, play critical roles in binding regulatory protein factors and influence gene expression by affecting DNA folding. This study investigates the relationship between purine stretches and cancer development, considering the aromaticity of purines, quantified by methods like Hückel's rule and NICS calculations, and the importance of the flanking sequence context. A pronounced avoidance of long purine stretches by typical cancer mutations was observed in public data on the intergenic regions of cancer patients, suggesting a role of intergenic sequences in chromatin reorganization and gene regulation. A statistically significant shortening of purine stretches in cancerous tumors (p value < 0.0001) was found. The insights into the aromatic nature of purines and their stacking energies explain the role of purine stretches in DNA structure, contributing to their role in cancer progression. This research lays the groundwork for understanding the nature of purine stretches, emphasizing their importance in gene regulation and chromatin restructuring, and offers potential avenues for novel cancer therapies and insights into cancer etiology. [ABSTRACT FROM AUTHOR]

Bisfunctional benzoxazine and polyether diamine‐based polymers show Arrhenius‐like stress‐relaxation varying with stoichiometry and polymerization temperatures proving vitrimeric behavior. Molecular structural investigations reveal the presence of different aminoalkylated phenols occurring at varying ratios depending on polymer composition and polymerization conditions. The vitrimeric mechanism is found to involve an amine exchange reaction of aminoalkylated phenols in an equilibrium reaction like a nucleophilic substitution reaction. As determined by molecular studies and dissolution experiments in reactive solvents, aliphatic and aromatic primary as well as aliphatic secondary amines in the polybenzoxazine structure can act as nucleophiles in reaction with electrophilic methylene bridges. Thus, aminoalkylated phenols proved to be a relevant structural motif resulting in a vitrimeric polybenzoxazine due to amine exchange reaction. [ABSTRACT FROM AUTHOR]

Integrated carbon capture and utilization (ICCU) simplifies the CO2 utilization process by converting chemically combined CO2 molecules into value-added chemicals, leading to a strong energy-saving effect by omitting the CO2 separation process. Two reaction routes for the hydrogenation of amine captured CO2 to methanol over heterogeneous catalysts were summarized: alcoholic hydroxyl groups-promoted CO2 hydrogenation process over Cu or Pd-based catalysts via formate and ester route, and methanol production from the direct hydrogenation of formate over Au-based catalyst. The technical effectiveness of concurrent carbon capture with heterogeneous catalysis toward methanol via alcoholic hydroxyl groups-promoted CO2 hydrogenation is similar to that of the gas-phase CO2 hydrogenation to methanol over heterogeneous catalysts. The sintering of the catalysts, the phase change of the supports, the combination of amines and the catalysts (namely leaching), and the reaction of water with the supports can cause a decrease in the performance of the catalysts. Thus, it is important to rationally design next-generation stable catalysts to achieve amine captured CO2 hydrogenation to methanol while at the same time regenerating amines. The development of heterogeneous catalysts for methanol synthesis in the liquid phase and the development of the CO2 capture process for subsequent conversion(1 ~ 70%) were carefully reviewed. The integration and optimization of multi-pollutant efficient removal technology, selectively coupled CO2 capture technology, and selective routes for methanol synthesis can achieve industrial verification in typical power plants, which is of great significance in promoting energy conservation, emission reduction, and low-carbon footprint. [ABSTRACT FROM AUTHOR]

Coordination compounds of polydentate nitrogen ligands with metals are used extensively in research areas such as catalysis, and as models of complex active sites of enzymes in bioinorganic chemistry. Tris(2-pyridylmethyl)amine (TPA) is a tripodal tetradentate ligand that is known to form coordination compounds with metals, including copper, iron and zinc. The related compound, tris[(6- bromopyridin-2-yl)methyl]amine (TPABr3), C18H15Br3N4, which possesses a bromine atom on the 6-position of each of the three pyridyl moieties, is also known but has not been heavily investigated. The molecular structure of TPABr3 as determined by X-ray diffraction is reported here. The TPABr3 molecule belongs to the triclinic, P1 space group and displays interesting intermolecular Br...Br interactions that provide a stabilizing influence within the molecule. [ABSTRACT FROM AUTHOR]

The conventional use of polyurethane in various applications is hindered by significant challenges, such as toxicity concerns, moisture sensitivity, and environmental impact. In response, there has been a notable surge in research focusing on bio-based alternatives, particularly non-isocyanate polyurethanes (NIPUs), aligning with sustainable development objectives. NIPUs offer a promising solution by eliminating the need for isocyanates, employing cyclic carbonates and diamines instead. Out of various sources available, non-traditional vegetable oils present a viable starting material for cyclic carbonate synthesis due to their availability, renewability, and affordability. However, despite the growing interest in NIPUs, there remains a scarcity of literature on the utilization of non-traditional oils for their development. This short review aims to fill this gap by providing an overview of bio-based NIPUs synthesized from non-traditional vegetable oils such as jatropha oil, castor oil, lignin oil, linseed oil, and rubber seed oil. The review covers the synthesis methods of NIPUs via polyaddition reactions of carbonates and amines, detailing properties, advantages, and applications of each oil-based NIPU. Furthermore, by identifying research gaps and proposing potential solutions, this paper aims to encourage researchers to consider non-traditional oils for NIPU synthesis, facilitating significant advancements in the field. [ABSTRACT FROM AUTHOR]

Compared to modifications at the molecular periphery, skeletal adjustments present greater challenges. Within this context, skeletal rearrangement technology stands out for its significant advantages in rapidly achieving structural diversity. Yet, the development of this technology for ring contraction of saturated cyclic amines remains exceedingly rare. While most existing methods rely on specific substitution patterns to achieve ring contraction, there is a persistent demand for a more general strategy for substitution‐free cyclic amines. To address this issue, we report a B(C6F5)3‐catalyzed skeletal rearrangement of hydroxylamines with hydrosilanes. This methodology, when combined with the N‐hydroxylation of amines, enables the regioselective ring contraction of cyclic amines and proves equally effective for rapid reorganization of acyclic amine skeletons. By this, the direct scaffold hopping of drug molecules and the strategic deletion of carbon atoms are achieved in a mild manner. Based on mechanistic experiments and density functional theory calculations, a possible mechanism for this process is proposed. [ABSTRACT FROM AUTHOR]

A convenient synthetic protocol for diverse 4, 5-disubstituted-6-methyl-2-(methylthio)pyrimidines was successfully developed by Sonogashira reactions. In the presence of Pd-Cu catalysts, one-pot, multi-step reaction of amines, terminal alkynes, and 4-chloro-5-iodo-6-methyl-2-(methylthio)pyrimidine in DMF at 80°C resulted in 4, 5-disubstituted-6-methyl-2-(methylthio)pyrimidine derivatives in moderate to good yields. [ABSTRACT FROM AUTHOR]

Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to a smooth [1,3]-proton shift reaction with a high chirality transfer, affording the corresponding rearranged products in acceptable yields. Without purification, these products were subjected to acid hydrolysis and the subsequent N-Cbz protection, providing the optically active tetrafluoroethylenated amides in moderate three-step yields.

Abstract This study developed a novel and highly active heterogeneous catalyst of nickel nanoparticles supported on β-cyclodextrin-grafted magnetic Fe3O4 nanoparticles (Ni@β-CD@Fe3O4). β-CD, a biodegradable, biocompatible, green, and non-toxic cyclic oligosaccharide, was modified with Fe3O4 nanoparticles to create β-CD@Fe3O4. The nickel was then immobilized onto this support. The catalyst was characterized using FT-IR, XRD, TEM, AAS, FE-SEM, TGA, EDX, DRS-UV-Vis spectra, and VSM techniques. The catalytic activity of Ni@β-CD@Fe3O4 was evaluated for the reduction of nitroarene compounds in water at 25 ℃. This nanocatalyst indicated great activity and selectivity in reducing various nitroarenes, including nitrobenzene, nitroaniline, nitrotoluene, and nitrophenol derivatives. Additionally, the catalyst showed significant reusability and could be easily separated using an external magnet, highlighting its potential for green chemistry and sustainable industrial applications.

Silica and silicate scale deposition in the production systems resulted in reduced production rates and equipment damages. Chemical scale inhibition using squeeze method is advantageous for petroleum reservoir conditions. This paper aims to assess the adsorption and squeeze performance of developed scale inhibitors that consist of polyamidoamine (PAMAM) dendrimers and pteroyl-L-glutamic acid (PGLU). Commercial inhibitor, diethylenetriamine penta(methylene phosphonic acid), also known as DETPMP, was also used to benchmark the laboratory findings. Static adsorption test and core flooding were performed to investigate the adsorption characteristics and retention of the inhibitors in Berea sandstone cores. Simulation was also conducted to estimate the squeeze performance of the inhibitors. Results revealed that PAMAM-2-PGLU scale inhibitor exhibited the highest adsorption and retention in the sandstone core. The treatment of PAMAM-2-PGLU and PAMAM-1-PGLU inhibitors increased the core permeabilities. SQUEEZE IV model predicted that both PAMAM-PGLU inhibitors yielded longer squeeze lifetime than DETPMP inhibitor. Both experimental and simulation results showed good fit in terms of adsorption and squeeze lifetime. In this paper, the tested PAMAM-PGLU scale inhibitors have demonstrated better adsorption, retention, and squeeze lifetime in sandstone formation. They could offer effective and low-toxicity alternatives to commercial inhibitors due to raising environmental concerns.

Combining simple amines with the bench‐stable sulfinylamine Tr‐NSO allows in situ preparation of reactive alkyl sulfinylamines, which when combined with alkyl radicals generated by photocatalytic decarboxylation, provides N‐alkyl sulfinamides. The reactions are broad in scope and tolerate a wide variety of functional groups on both the acid and amine components. The sulfinamide products are used to prepare a selection of challenging S(VI) products. The method provides a convenient way to use reactive and unstable alkyl sulfinylamines. [ABSTRACT FROM AUTHOR]

Porphyrins‐based porous organic polymers (POP) were widely used in photocatalytic oxidation under visible light owing to their superiority in the activation of oxygen. In contrast, the efficiency is usually limited due to the fast recombination and slow electron transfer. Herein, we report the use of a trioporphyrins‐based covalent triazine framework (Por‐CTF) as visible‐light‐active photocatalyst for the coupling oxidative of amines to imines at room temperature. By incorporating the π‐conjugated porphyrin building block led to the enhanced electron transport between molecules, and the extended recombination time of excited electrons. The photocatalytic efficiency of Por‐CTF is superior to that of polymer in absence of triazine framework (POP‐TSP), which was prepared by radical polymerization using tetra‐(4‐vinylphenyl) porphyrin (TSP) as monomer. Por‐CTF catalyst presented excellent efficiency for various primary amines and stability. This work provides a reasonable guidance of catalyst molecular structure design for enhancing efficiency in the photocatalytic oxidation. [ABSTRACT FROM AUTHOR]

A highly effective approach has been proposed for the synthesis of unique imidazole aniline compounds via a reaction sequence including acylation of substituted anilines with 2-chloroacetyl chloride, alkylation of 2-butyl-5-chloro-1H-imidazole-4-carbaldehyde with the resulting 2-chloroacetanilides, and con-densa-tion of 2-(2-butyl-5-chloro-4-formyl-1H-imidazol-1-yl)-N-(substituted phenyl)acetamides with 4-{4-[5-(amino-methyl)-2-oxo-1,3-oxazolidin-3-yl]phenyl}morpholin-3-one. The newly synthesized compounds have been screened for their in vitro antimalarial potential against Plasmodium falciparum and found to exhibit incredibly impressive half-maximum inhibitory concentration (IC50) values. Molecular docking has been performed for the most active compound and dihydrofolate reductase–thymidylate synthase (DHFR-TS) from the wild-type Plasmodium falciparum, and hydrogen bond interactions between the amino acid residues Ser167 and Ser111 and azomethine and imidazole nitrogen atoms, respectively, have been revealed. [ABSTRACT FROM AUTHOR]

Development of elegant, selective, and efficient strategies for the production of value‐added platform chemicals from renewable feedstocks are in high demand to achieve the future needs and sustainable goals. In this context, an efficient acid‐promoted synthesis of highly valuable hydroxymethylfurfural (HMF) has been demonstrated from glucose, a major constituent of lignocellulosic biomass. The major challenge in the conversion of glucose to HMF is the selective isomerization of glucose to ketose, which in the present work has been successfully addressed through the amine‐mediated rearrangement of glucose to aminofructose under Amadori rearrangement. Importantly, subsequent dehydration step affords HMF and regenerates the amine employed in the first step, which could be readily recovered. In addition, scale‐up and successful integration into one‐pot synthesis of HMF proves the efficiency and applicability of the present transformation in large scale application. In addition, the method was also successfully extended to other monosaccharides and disaccharides to produce HMF. [ABSTRACT FROM AUTHOR]

This study aims to analyze the degradation behavior and mechanisms of amine-cured epoxy asphalt (EA) under the combined effects of ultraviolet (UV) radiation, oxygen, and temperature. To achieve this, amine-cured epoxy resin (ER) and EAs containing 35%, 45%, and 55% asphalt content were prepared and subjected to simulated UV-based aging. Various analytical techniques were employed to investigate the mechanical properties, microstructure, morphology, and oxidation layer of ER and EAs. The results indicate that after UV-based aging, ER and EAs with 35%–45% asphalt content experienced an increase in mass, a decrease in strength and glass transition temperature. In comparison, EAs with 55% asphalt content exhibited the opposite trends. The elongation and (Tanδ)max of ER and EAs reduced, whereas the storage modulus and hardness at mid to high temperatures rose. At the microstructural level, the degradation of the resin phase was confirmed by changes in ether, ester, and amide groups, whereas the generation of sulfoxide groups was associated with the oxidation of the asphalt phase. Compared with ER, the surface of EA has obvious defects after aging, which is the main reason for the decrease in contact angle. As the asphalt content increases, EAs exhibit higher carbonyl concentration, more profound oxidation, and more obvious performance degradation. This trend suggests that the resin phase mitigates the aging of the asphalt phase by absorbing harmful UV radiation and oxygen. [ABSTRACT FROM AUTHOR]

Mixed-ligand complexes of Pd(II) and Pt(II) with 2H-benzo[e][1,3] oxazine-2,4(3H)-dione (HBzoxe), tertiary phosphines (dppe, dppp, dppf and Ph3P), 2,2′-bipyridine (Bipy) and 1,10-phenanthroline (Phen) have been synthesized and characterized by molar conductance measurements, elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopy. In addition, the antimicrobial activity assay studies. The results showed that the HBzoxe ligand behaves as a bidentate chelation ligand through the O and N atoms in [M(Bzoxe)2] {MII = Pd(1) and Pt(2)} complexes, whereas it acts as monodentate ligand through the oxygen atom in complexes (3–14) to afford a square planner geometry around Pd(II) and Pt(II) for all of the complexes. All of the complexes were moderately active on all the bacteria tested (Staphylococcus aureus and Escherichia coli). Hirshfeld surface analysis was carried out to investigate the cooperative non-covalent supramolecular interactions within the various complexes. [ABSTRACT FROM AUTHOR]

Two novel viologen-functionalized Supramolecular compounds {[H2bpybc]0.5⋅[H2BTEC]0.5⋅ H2O}n (1) and {[H2bpybc]⋅[H3BTEC]2⋅2H2O}n (2), were synthesized through a solution-based approach in the presence of 1,1'-bis((4-carboxybenzyl)-4,4'-bipyridine) chloride (H2bpybc⋅2Cl), 1,2,4,5-benzenetetracarboxylic acid (H4BTEC), and Zn(NO3)2⋅6H2O. Single crystal X-ray diffraction analysis showed the three-dimensional supramolecular network structures within compounds 1 and 2. Notably, these compounds exhibit reversible photochromism due to the formation of viologen radicals, facilitating electron transfer. The order of light response time follows the sequence 1 > 2. To further elucidate the discoloration mechanism, Time dependent density functional theory (TDDFT) was employed. Additionally, compound 1 showed interesting photomodulated fluorescence behavior. Faster responsive rate is observed in the system of 1 due to its shorter D–A distance and intramolecular hydrogen bonding structure. Remarkably, compound 1 displays selective sensing capabilities towards NH3 and triethylamine among various organic amines. Given its photochromic properties, compound 1 holds promise as a potential candidate for photochromic materials, anti-counterfeit paints, and information monitoring technology applications. [ABSTRACT FROM AUTHOR]

The N‐methylation reaction of amines with methanol via the borrowing‐hydrogen strategy is an important method for the construction of C−N bonds. Compared with other C1 sources, such as toxic formaldehyde or expensive formic acid, methanol is more suitable for N‐methylation reactions due to its eco‐friendliness and low price. Using this strategy, various types N‐methylated products, including biological and pharmaceutical molecules have been prepared. Here, we present a thorough survey of decades of articles showing current developments in N‐methylation reactions with methanol. We discuss homogenous, heterogenous and light‐driven catalytic systems for both N‐methylation and N,N‐dimethylation reactions. This review presents the shortcomings of current developments and provides future development progress in N‐methylation reactions with methanol. [ABSTRACT FROM AUTHOR]

In this study, the high potential tertiary N-methyl-4-piperidinol or MPDL (0.25–1.00 M) was blended with 5 M monoethanolamine (MEA) to formulate 5.25–6.00 M MEA-MPDL solvent and compare with the benchmark 5 M MEA. It was found that the density and the Henry's constant slightly decreased, while the viscosity increased as the MPDL concentration in the blend increased. Even though the equilibrium CO2-loaded viscosity considerably increased (by 34.3–40.2%) as the MPDL content increased, it was still in a great operating region of less than 10 mPa.s. Experimental overall reaction kinetics constant ( k ov ) was well corresponding with the zwitterion mechanism of MEA and the base-catalyze hydration mechanism of MPDL based absorption kinetics model, with %AAD of 0.56%. Interestingly, an addition of MPDL into 5 M MEA slightly enhanced k ov (1.2–3.3% increment) and considerably favored absorption capacity (13–31% elevation), and regeneration heat duty (28–47% reduction), respecting 5 M MEA. The proposed strategic blending can maintain the overall solvent reactivity at the same level of the benchmark, while obviously increase the absorption capacity and largely reduce the regeneration heat duty. This highly favors a solvent upgrading for the existing 5 M MEA based CO2 capture plant. According to the recent data, 5 M MEA + 1.00 M MPDL was suggested. Since the blend was formulated at high concentration, its corrosiveness should also be considered. [ABSTRACT FROM AUTHOR]

Herein, a microwave promoted tandem reaction of free primary arylamines with diazo compounds in water for clean synthesis of 2,2‐disubstituted 3‐oxindoles is present. Water plays important roles in the whole cascade process: O−H insertion to diazo, air oxidation, ortho C−H functionalization, cyclization and 1,2‐ester migration. In particular, water plays a mediation role in the site selective ortho‐C−H addition. [ABSTRACT FROM AUTHOR]

In drilling, mitigating wellbore instability issues in reactive shale formations is crucial and takes top priority. These instabilities often lead to significant disruptions in drilling operations, resulting in loss of time and increased operational costs. This study is aimed at mitigating these challenges, with a primary focus on reducing filtration loss volume and enhancing wellbore stability within shale formations. In this study, the filtration properties of water-based mud along with Ranikot shale stability were investigated in presence of PAC and Amine. In this revolutionary study, the synergistic effect of two additives on the filtration properties of water-based mud and Ranikot shale was comprehensively investigated and visualized through 3D surface plots. A total of 13 distinct mud samples were meticulously formulated using Central Composite Design, a pivotal subset of response surface methodology. The result of the study shows that there were no drastic variations in the mud weight recorded with changes in concentration of PAC and amine. Moreover, sample 4 with least concentration of both additives demonstrates a highest fluid loss volume of 13.5 mL/30 min, which highlights the importance of optimal concentration of PAC and amine in WBM. Furthermore, this low concentration sample formed a mud cake with rough and thick texture, exhibiting a high permeability of 0.54371 µD. In contrast, samples with high concentrations were extremely successful in maintaining a low fluid loss volume and forming a dense and compacted mud cake. Additionally, the combined influence of these particle on enhancing the hydrophobic behavior of the shale sample was also investigated. Sample 4 with least particles concentration demonstrated a contact angle of 37.398°, while the highest contact angle of 86.792° was exhibited by sample with greater concentration of amine and PAC. The result showed that the high concentration of PAC and amine in the mud sample led to a substantial enhancement of the shale hydrophobic character. This shows that when PAC and amine interact with the shale pellets it reduces the affinity for water and thereby increases its resistance to water ingress, which play a pivotal role in wellbore stability. The study's outcomes underscore the remarkable efficacy of PAC and amine in considerably reducing the filtrate loss, thereby leading to enhanced drilling efficiency and operational performance. [ABSTRACT FROM AUTHOR]

The synthesis of tertiary amines from alcohols (i.e. heptanol, dodecanol, cyclohexanol, benzylalcohol) and secondary amines (Me2NH (DMA), nPr2NH, nBu2NH) has been achieved in one step using trimetallic nanoparticles (NPs) displaying a magnetic core (Co4Ni6 and Fe3Ni7) and a Cu shell as both catalysts and heating agent in the presence of an alternating magnetic field. This methodology limits the redistribution reactions occurring on amines at high temperature leading to both much higher conversion and selectivity in the absence of solvent than usually observed using conventional heating. Moreover, Co4Ni6@Cu NPs were found moisture resistant, thereby allowing for performing the reaction with commercial DMA in water (40 % wt) with again high conversion and selectivity. [ABSTRACT FROM AUTHOR]

Herein, we disclose a new strategy that rapidly and reliably incorporates bromine atoms at distal, secondary C(sp3)−H sites in aliphatic amines with an excellent and predictable site‐selectivity pattern. The resulting halogenated building blocks serve as versatile linchpins to enable a series of carbon‐carbon and carbon‐heteroatom bond‐formations at remote C(sp3) sites, thus offering a new modular and unified platform that expediates the access to advanced sp3 architectures possessing valuable nitrogen‐containing saturated heterocycles of interest in medicinal chemistry settings. [ABSTRACT FROM AUTHOR]

We have developed a one-pot, four-component synthetic approach utilizing 5-sulfosalicylic acid dihydrate (5-SSA.2H2O) as an organocatalyst, enabling the synthesis of polyfunctional 3-pyrrolin-2-one molecules by employing dialkylacetylenedicarboxylate, amines, and either formaldehyde or aromatic aldehydes at room temperature. This approach presents numerous notable benefits such as shorter reaction time, simple and eco-friendly procedure, excellent yield, broad applicability across various substrates, and the use of a cost-effective, easily accessible and biodegradable catalyst. The structures of the 3-pyrrolin-2-one molecules were confirmed using techniques such as FTIR, 1HNMR, 13CNMR and HRMS. Overall, this study demonstrates a promising method for producing environmentally friendly polyfunctional 3-pyrrolin-2-one efficiently and smoothly at ambient temperature. [ABSTRACT FROM AUTHOR]

Objectives: Reflecting the need for an effective support for the daily oral hygiene routine of patients experiencing (symptoms of) gum inflammation, a new mouthwash has been developed containing an amine + zinc lactate + fluoride system. The in vitro efficacy of this product was assessed using traditional laboratory methods, as well as novel experimentation. Materials and Methods: This mouthwash has been evaluated in a series of laboratory tests including two short interval kill tests (SIKTs), a 12‐h (longer term) biofilm regrowth assay, a plaque glycolysis assay, and an aerobic, repeated exposure biofilm model, as well as tests for soft tissue uptake and LPS neutralization. Results: Several laboratory studies demonstrate that a mouthwash containing an amine + zinc lactate + fluoride system provides short‐term and long‐term antibacterial activity. While the immediate efficacy of this formula has been shown to be driven by the presence of the amine, zinc lactate provides a long‐term antibacterial effect, as well as is able to inhibit bacterial metabolism. Conclusions: This research provides the basis for understanding the mode of action of this new mouthwash formulation and explains the previously observed clinical efficacy of this formula against plaque and gingivitis. [ABSTRACT FROM AUTHOR]

Biocatalysis provides an attractive approach to facilitate synthetic reactions in aqueous media. Motivated by the discovery of promiscuous aminolysis activity of esterases, we exploited the esterase from Pyrobaculum calidifontis VA1 (PestE) for the synthesis of carbamates from different aliphatic, aromatic, and arylaliphatic amines and a set of carbonates such as dimethyl‐, dibenzyl‐, or diallyl carbonate. Thus, aniline and benzylamine derivatives, aliphatic and even secondary amines could be efficiently converted into the corresponding benzyloxycarbonyl (Cbz)‐ or allyloxycarbonyl (Alloc)‐protected products in bulk water, with (isolated) yields of up to 99 %. [ABSTRACT FROM AUTHOR]

We report on the preparation of a polyethyleneimine‐incorporated hydroxyapatite (PEI‐HAP) and its enhanced colloidal stability. Three PEI‐HAPs having different amine contents are synthesized by hydrothermal treatment (200 °C) of the HAP prepared at room temperature (rt‐HAP). The crystallinity of PEI‐HAP is improved compared to rt‐HAP due to the heat treatment. In addition, the size of PEI‐HAP (50.4 nm) increased compared to rt‐HAP (32.1 nm) after heat treatment. However, the presence (or concentration) of PEI has little effect on the crystallinity and size of the samples. Ninhydrin test indicates the presence of amine group in PEI‐HAPs. XPS experiments verified that maximum amine content amounts to 2.81%. As the amount of amine increases, the zeta potential is changed from −22.6 to +31.7 mV due to the adsorption of PEI on HAP surface. Consequently, the sample having high positive valuable zeta potential of +31.7 mV exhibits colloidal stability of more than 6 h. [ABSTRACT FROM AUTHOR]

Absorption is the most widely used carbon dioxide (CO2) removal technology. The CO2 absorption performance of monoethanolamine (MEA), the most commonly used CO2 absorbent, can be improved by suspending nanoparticles. This work examined the performance of graphene nanoplatelets (GNPs) as additives to enhance CO2 absorption in MEA. The GNPs were characterized by HRTEM, FTIR, and XRD. The study examined the influence of GNP concentrations on CO2 absorption at room temperature. The images from HRTEM confirmed that the implemented graphene consists of several layers of graphene sheets. Increasing the loading of particles increased the solubility of CO2 until the optimum concentration was reached. From this work, it is evident that incorporating GNPs into MEA enhances the CO2 absorption performance of MEA. Thus, the addition of nanoparticles to the absorbent can enhance its CO2 absorptivity. [ABSTRACT FROM AUTHOR]

Carbon capture is an essential technology in mitigating climate change by reducing greenhouse gas emissions, particularly CO2, from industrial and power generation sources. This study investigates the post-combustion carbon capture using amine-based absorbents and evaluates the efficiency of CO2 removal and energy consumption in absorption section of this process. Through simulation with Aspen-Hysys and design of experiment (DoE) using response surface methodology (RSM) as well as optimization, the study investigates the effects of operational parameters such as temperature and pressure of absorption column, number of stages in absorption column, flue gas/amine ratio, and CO2 mol fraction in inlet flue gas on CO2 capture efficiency and energy consumption. Key performance metrics such as capture efficiency, energy consumption for compressor and cooler, and optimal operational conditions were analyzed. In optimum conditions, CO2 removal efficiency of more than 98 % with possible minimum energy consumption of 6035 KW as well as minimum number of stages of 16 were achieved. The results significantly highlight not only improvements in capture efficiency, reduced energy and capital cost savings, but also address the significant environmental benefits, providing crucial insights into the design and operation of more efficient carbon capture systems.

The study is dedicated to the investigation of the catalytic activity of zinc carboxylates in the condensation reaction of camphor with aliphatic diamines. The reaction of camphor with 1,6-hexanediamine was selected as the model system. The research demonstrated that the reaction does not proceed without a catalyst, while the use of zinc carboxylates as catalysts leads to a higher conversion and selectivity compared to the classical catalyst for this reaction, Et2O∙BF3. The best results were achieved using zinc 2-ethylhexanoate, which provided an 88.4 % conversion of camphor and a 76.9 % selectivity for the formation of diimine. It was established that the catalytic activity of zinc carboxylates in the condensation reaction of camphor with diamines is related to the structure of the acid residue of the salt. Based on the obtained data, a reaction mechanism was proposed, associated with the formation of a complex between the zinc carboxylate and the initial amine, which is confirmed by FTIR and UV–vis spectroscopic data.

ABSTRACTFunctional ionic liquids have been widely used in the fields of synthetic chemistry, analytical chemistry, electrochemistry and material chemistry owing to their excellent properties such as easy structure modification and adjustable properties. In this work, a series of basic functionalized ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) or hexamethylenetetramine (HMTA) with various halogenated hydrocarbons, then these functional ionic liquids and water were used as solvent-catalyst system in the Knoevenagel reaction of various aldehydes with ethyl cyanoacetate or malononitrile, the influence of the structure of the ionic liquid and the content of water was investigated. The results showed that the composite solvent-catalyst system mixed by the functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo [2.2.2] octane bromide with water can effectively promote the Knoevenagel reaction and the alkalinity of amine and hydrogen bond play an important role. Aromatic aldehydes with electron-donating or electron-withdrawing groups can obtain the target product at an excellent yield (79-99%). It is worth noting that the polycyclic aromatic aldehydes with high steric hindrance, 86%-95% yields of the object products were also obtained after 15 h-25 h. Furthermore, the catalyst could be reused for 6 times without any loss in its catalytic activity.The composite solvent-catalyst system mixed by the Functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo[2.2.2]octane bromide with water can effectively promote the Knoevenagel reaction, even for the electron-rich aromatic aldehydes with poor reactivity, high yields of the target products and fast reaction rate were also obtained at room temperature.

In the title molecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, five-membered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitrogen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O—H...N and N—H...O hydrogen bonds plus C—H...π(ring) and weak π-stacking interactions.

With the growing significance of green chemistry in organic synthesis, electrochemical oxidation has seen rapid development. Compounds undergo oxidation–reduction reactions through electron transfer at the electrode surface. This article proposes the use of electrochemical methods to achieve cleavage of the benzyl C–N bond. This method selectively oxidatively cleaves the C–N bond without the need for metal catalysts or external oxidants. Additionally, primary, secondary, and tertiary amines exhibit good adaptability under these conditions, utilizing water as the sole source of oxygen. [ABSTRACT FROM AUTHOR]

[Display omitted] Photocatalytic oxidative coupling of amines is considered a mild, efficient, and sustainable strategy for the synthesis of imines. As a versatile organic semiconductor, conjugated microporous polymers (CMPs) are attractive in photocatalysis areas due to the diversity of their polymeric monomers. Herein, we report that in addition to the design of monomers, size-confined polymerization is also a feasible strategy to modulate the structure and photocatalysis properties of CMPs. We adopted dibromopyrazine as polymeric units to prepare pyrazine-involved hollow spherical CMPs (H-PyB) using a template method and successfully performed size-confined polymerization of hollow samples by resizing the templates. Interestingly, the small confinement space induced the formation of CMPs with better conjugate extensibility, resulting in enhanced conductivity, narrowed bandgaps, improved photoelectric performance, etc. As a result, small-sized H-PyB CMPs had superior activity for the photocatalytic oxidation of amines. Particularly, the smallest H-PyB CMPs that we designed in the present work exhibited excellent performance for the photocatalytic coupling oxidation of amines. When using benzylamine as a model substrate, the yield of the corresponding imine reached ∼ 113 mmol·g−1·h−1, accompanied by almost 100 % selectivity. Furthermore, the as-designed confined samples exhibited stable photocatalytic activity as well as good applicability for oxidative coupling of different amines. This work not merely reports a kind of CMP photocatalysts with excellent performance for the imine coupling oxidation but also proposes an alternative strategy for constructing high-performance organic photocatalysts by size-confined synthesis. [ABSTRACT FROM AUTHOR]

The present work investigates the volumetric and viscometric properties of an aqueous solution of 1,2-dimethylethylenediamine (DEEDA) over an entire concentration range and an absorber operating temperature range of 313.15K-333.15K at atmospheric pressure. The investigated volumetric properties included the density, excess molar volume, partial molar volume, and the investigated viscometric properties included the viscosity, viscosity deviation, free energy for activation of viscous flow, excess free energy for activation of viscous flow, and excess entropy for activation of viscous flow. The results indicated that there are strong intermolecular interactions and suitable molecular packing in the binary DEEDAewater mixture. Hence, the mixture was found to deviate from a real mixture according to the calculated excess properties. The DEEDA solvent's preliminary volumetric and viscometric properties revealed convincing potential as a novel amine for carbon capture. Additionally, the Redlich-Kister-based correlations showed favorable correlative performance for excess molar volume, viscosity deviation, and excess entropy for activation of viscous flow. [ABSTRACT FROM AUTHOR]

Stable boroxine-amine adducts comprising dative B←N bond(s) were prepared by mechanochemically-induced reactions of phenylboronic acid (PBA) and amines (pyridine, DMAP, 1Hpyrazole, piperidine, DABCO, hexamethylenetetramine, or 4,4'-bipyridine). In-situ Raman monitoring, ex-situ PXRD and DFT calculations were used for product identification. Stoichiometry of the product (3: 1, 3:2 or 6:1 adduct) was controlled by the amine structure and the molar ratio of the reactants. The 1:2 Hbonded assembly of PBA and 4,4'-bipyridine (bpy) was confirmed as an intermediate in the adduct formation for bpy. Competitive binding experiments indicated that the exchange of the amines in the 3:1 adducts follows the computed adduct stabilities that increase with the amine basicity. Following the DFT prediction, the first adduct with two different amines, DMAP and pip, bound to one boroxine moiety was isolated and structurally characterized. Results show that calculations can be used to predict possible and preferred product(s) and their spectral characteristics. [ABSTRACT FROM AUTHOR]

We demonstrate the reduction of gold (Au) on silica monoliths by surface decoration of amine and imine (formed by reaction of amine present in 3‐amino propyl triethoxy silane (APTES) and acetone) functionalities on the surface of silica. The reduction of Au3+ to Au0 was confirmed by X‐ray diffraction (XRD), UV‐Diffuse reflectance and X‐ray Photo electron spectroscopic techniques. Without employing the conventional strategies with reducing agents like sodium borohydride and sodium citrate, here, the surface functionalized amine and imine was found to reduce the metal ions, additionally, the surface silanols was found to anchor and serve as the adsorption sites to hold the metal ions prior to reduction. The control experiment was performed with silica monoliths without the surface functionalities displayed no evident reduction of Au3+ to their respective metallic form. Interestingly, the reduction of Au was found to be more facile on imine modified silica, due to the strong electrostatic interaction of highly polarized imine with Au3+ ions. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of previously unknown azides, iminophosphoranes and amines from commercially available mucochloric and mucobromic acids is reported. The reaction of 5-alkoxy-3,4-dihalo-2(5H)-furanones with sodium azide resulted in the regioselective formation of furanone 4-azidoderivatives. A series of novel iminophosphoranes was obtained from the reaction of corresponding azides with triphenylphosphine. Reduction of iminophosphoranes with stannous chloride dihydrate led to the heterocycles, possessing an amino group at the C4 carbon atom of the unsaturated γ-lactone ring. [ABSTRACT FROM AUTHOR]

The odor space of aquatic organisms is by necessity quite different from that of air-breathing animals. The recognized odor classes in teleost fish include amino acids, bile acids, reproductive hormones, nucleotides, and a limited number of polyamines. Conversely, a significant portion of the fish olfactory receptor repertoire is composed of trace amine-associated receptors, generally assumed to be responsible for detecting amines. Zebrafish possess over one hundred of these receptors, but the responses of olfactory sensory neurons to amines have not been known so far. Here we examined odor responses of zebrafish olfactory epithelial explants at the cellular level, employing calcium imaging. We report that amines elicit strong responses in olfactory sensory neurons, with a time course characteristically different from that of ATP-responsive (basal) cells. A quantitative analysis of the laminar height distribution shows amine-responsive cells undistinguishable from ciliated neurons positive for olfactory marker protein. This distribution is significantly different from those measured for microvillous neurons positive for transient receptor potential channel 2 and basal cells positive for proliferating cell nuclear antigen. Our results suggest amines as an important odor class for teleost fish. [ABSTRACT FROM AUTHOR]

In the title molecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, fivemembered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitrogen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O--H...N and N--H...O hydrogen bonds plus C--H...π(ring) and weak π-stacking interactions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fossil fuel power plants are the primary contributors to carbon dioxide (CO2) emissions, necessitating effective and stable methods for adsorbing CO2 from flue gas under diverse conditions. Achieving this remains challenging due to the complexity of flue gas compositions and the prolonged operation of adsorption processes. RESULTS: This study focuses on enhancing CO2 adsorption in flue gas using attapulgite (ATP), activated by acid and modified with tetraethylenepentamine (TEPA) via an impregnation method. Characterization through X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and N2 adsorption–desorption revealed that acidic treatment removed impurities, enhancing BET (Brunauer–Emmett–Teller) surface area. TEPA modification significantly increased CO2 adsorption capacity by providing more active sites. Notably, 30TEPA/HATP exhibited the best performance at 3.28 mmol g−1. Optimal CO2 adsorption occurred at 60 °C in simulated flue gas, with water improving amine utilization. Furthermore, 30TEPA/HATP demonstrated consistent CO2 adsorption capacity (3.04 mmol g−1) across concentrations (10–20 vol%) and maintained stability after ten cycles, experiencing only a 7.0% decrease. CONCLUSION: The findings underscore the success of low‐cost ATP, modified with TEPA, in achieving excellent CO2 capture and stability under diverse flue gas conditions. This material holds promise for practical engineering applications in mitigating carbon emissions from fossil fuel power plants. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

This works documents a new silica gel-supported nanocatalyst (Si@NSBPdNPs 3) with low Pd loadings for n-alkylation reactions at room temperature. Post synthesis characterisation using SEM-EDX and ICP techniques provided a quantitative assessment of palladium species. Additionally, TEM analysis unveiled an average palladium nanoparticle size of 5.87 ± 0.2 nm. In-depth X-ray Photoelectron Spectroscopy (XPS) analysis revealed its predominant composition as Pd(0) complexed to a Schiff base ligand on low cost silica matrix. The nanocatalyst exhibited high efficacy in the catalysis of n-alkylation (Michael addition) reactions with various α,β-unsaturated Michael acceptors, yielding the corresponding n-alkyl products at room temperature with exceptional yields. Notably, the catalyst exhibited good stability and could be easily separated from the reaction mixture. Moreover, the catalyst displayed recyclability potential, maintaining its original catalytic efficacy for up to seven cycles without any discernible loss.

Abstract Objectives Reflecting the need for an effective support for the daily oral hygiene routine of patients experiencing (symptoms of) gum inflammation, a new mouthwash has been developed containing an amine + zinc lactate + fluoride system. The in vitro efficacy of this product was assessed using traditional laboratory methods, as well as novel experimentation. Materials and Methods This mouthwash has been evaluated in a series of laboratory tests including two short interval kill tests (SIKTs), a 12‐h (longer term) biofilm regrowth assay, a plaque glycolysis assay, and an aerobic, repeated exposure biofilm model, as well as tests for soft tissue uptake and LPS neutralization. Results Several laboratory studies demonstrate that a mouthwash containing an amine + zinc lactate + fluoride system provides short‐term and long‐term antibacterial activity. While the immediate efficacy of this formula has been shown to be driven by the presence of the amine, zinc lactate provides a long‐term antibacterial effect, as well as is able to inhibit bacterial metabolism. Conclusions This research provides the basis for understanding the mode of action of this new mouthwash formulation and explains the previously observed clinical efficacy of this formula against plaque and gingivitis.