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During the deamination and amination processes of meso -diaminopimelate dehydrogenase (meso -DAPDH) from Symbiobacterium thermophilum (StDAPDH), residue R71 was observed to display distinct functions. H154 has been proposed as a basic residue that facilitates water molecules to attack the D-chiral carbon of meso -DAP during deamination. Inspired by the phenomenon of R71, the effects of H154 during deamination and amination were investigated in this study with the goal of enhancing the amination activities of StDAPDH. Single site saturation mutagenesis indicated that almost all of the H154 mutants completely lost their deamination activity towards meso -DAP. However, some H154 variants showed enhanced k cat / K m values towards pyruvic acid and other bulky 2-keto acids, such as 2-oxovaleric acid, 4-methyl-2-oxopentanoic acid, 2-ketobutyric acid, and 3-methyl-2-oxobutanoic acid. When combined with the previously reported W121L/H227I mutant, triple mutants with significantly improved k cat / K m values (2.4-, 2.5-, 2.5-, and 4.0-fold) towards these 2-keto acids were obtained. Despite previous attempts, mutations at the H154 site did not yield the desired results. Moreover, this study not only recognizes the distinctive impact of H154 on both the deamination and amination reactions, but also provides guidance for further high-throughput screening in protein engineering and understanding the catalytic mechanism of StDAPDH. • H154 was first experimentally identified to be the fatal residue for deamination. • H154 mutation boosted the amination towards pyruvic acid and bulky 2-keto acids. • Coupling H154 variants with W121L/H227I resulted in enhanced amination activities. • The first report on the contrary effects of H154 during deamination and amination. • A reminder to update the high-throughput screening for DAPDH amination activity. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A visible‐light‐induced photoredox‐catalyzed regioselective and stereoselective C(sp2)–H amination of enamides with bench‐stable and easily accessible N‐aminopyridium salts is developed, affording synthetically and biologically prominent vicinal 1,2‐diamine scaffolds with broad substrate scope and excellent functional group compatibility. The transformation proceeded through a radical pathway involving the Giese addition of the relatively electrophilic N‐centered sulfonamidyl radical species to nucleophilic β‐olefinic position of enamides followed by the ensuing single electron oxidation and β‐H elimination, delivering geometrically‐defined Z‐configured β‐sulfonamidylated enamides. The operational simplicity, environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The synthesis of N‐glycosides has received significant attention due to their crucial role in carbohydrate chemistry. Despite considerable advancements developed in the construction of N‐glycosides, methods for the stereoselective construction of 2‐deoxy‐α‐N‐glycosides are still limited. Herein, we disclosed a nickel‐catalyzed hydroamination of glycals under mild conditions. This transformation could allow for the stereoselective synthesis of an array of 2‐deoxy‐α‐N‐glycosides with excellent α‐stereoselectivity. Nickel‐catalyzed glycosylation reactions, particularly those involving anomeric C(sp3)‐metal bond formation, have proven to be an effective and stereoselective strategy for producing various N‐glycosides. Additionally, with highlight of the application of this reaction, γ‐sugar amino acid derivatives were synthesized. [ABSTRACT FROM AUTHOR]

The document is the contents list for the journal "Chemical Communications" published on September 14, 2024. It includes highlights, feature articles, and communications on various topics in chemistry. Some of the topics covered include transition metal complexes, electrochemical biosensors, and photochemical catalysis. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

Pd-catalyzed regioselective amination of unactivated alkene remains a challenge and is of great interest. Herein, a palladium-catalyzed and ligand-controlled strategy for the Markovnikov selective oxidative amination of 4-pentenoic acid has been described. The protocol effectively reverses the carboxylic acid-directed anti-Markovnikov selectivity in oxidative amination of 4-pentenoic acid, successfully constructing γ-ketoamide derivatives. [ABSTRACT FROM AUTHOR]

A ruthenium‐catalyzed reductive amination via asymmetric transfer hydrogenation (ATH) has been used to perform an efficient dynamic kinetic resolution (DKR) of N‐aryl 2‐formyl pyrroles decorated with a phosphine moiety positioned at the ortho' position. The strategy relies on the labilization of the stereogenic axis in the substrate facilitated by a transient Lewis acid‐base interaction (LABI) between the carbonyl carbon and the phosphorus center. The reaction features broad substrate scope of aliphatic amines and N‐aryl pyrrole scaffolds, and proceeds under very mild conditions to afford P,N atropisomers in good to high yields and excellent enantioselectivities (up to 99 % ee) for both diphenyl and dicyclohexylphosphino derivatives. [ABSTRACT FROM AUTHOR]

Earth abundant metal‐based heterogeneous catalysts with highly active and at the same time stable isolated metal sites constitute a key factor for the advancement of sustainable and cost‐effective chemical synthesis. In particular, the development of more practical, and durable iron‐based materials is of central interest for organic synthesis, especially for the preparation of chemical products related to life science applications. Here, we report the preparation of Fe‐single atom catalysts (Fe‐SACs) entrapped in N‐doped mesoporous carbon support with unprecedented potential in the preparation of different kinds of amines, which represent privileged class of organic compounds and find increasing application in daily life. The optimal Fe‐SACs allow for the reductive amination of a broad range of aldehydes and ketones with ammonia and amines to produce diverse primary, secondary, and tertiary amines including N‐methylated products as well as drugs, agrochemicals, and other biomolecules (amino acid esters and amides) utilizing green hydrogen. [ABSTRACT FROM AUTHOR]

Multienzyme cascades (MECs) have gained much attention in synthetic chemistry but remain far from being a reliable synthetic tool. Here we report a four‐enzyme cascade comprising a cofactor‐independent and a cofactor self‐sustaining bienzymatic modules for the enantioselective benzylic C−H amination of arylalkanes, a challenging transformation from bulk chemicals to high value‐added chiral amines. The two modules were subsequently optimized by enzyme co‐immobilization with microenvironmental tuning, and finally integrated in a gas‐liquid segmented flow system, resulting in simultaneous improvements in enzyme performance, mass transfer, system compatibility, and productivity. The flow system enabled continuous C−H amination of arylalkanes (up to 100 mM) utilizing the sole cofactor NADH (0.5 mM) in >90 % conversion, achieving a high space‐time yield (STY) of 3.6 g ⋅ L−1 ⋅ h−1, which is a 90‐fold increase over the highest value previously reported. [ABSTRACT FROM AUTHOR]

Tris-(2-pyridylmethyl)amines (TPA or TPMA) are polipyrydine-based ligands extensively used in catalysis and supramolecular chemistry due their capability to form stable tetradentate complexes with a large variety of metals. The unsubstituted ligand, which is also commercially available, can be synthesised by consecutive alkylation of a picoline or by reductive amination of a pyridine aldehyde. In this article, we report a novel synthetic method which opens to the post-functionalisation of these ligands in the benzylic position. This novel derivatization strategy, beside providing synthetic access to novel structures and functions, has been used to prepare a series of metal complexes which have been tested in photochemical hydrogen evolution. [ABSTRACT FROM AUTHOR]

Machine learning has gained attention due to its ongoing advancements and diverse applications. Within the field of homogeneous catalysis, a prominent area of research in machine learning revolves around predicting reaction yield in Pd‐catalyzed Buchwald–Hartwig amination reactions. This study sought to determine the optimal descriptors for representing the both structural and physical information associated with the reaction, particularly focusing on product details. To achieve this, we assessed the utilization of product extended molecular fingerprints (PEMF) and selected physical parameters (SPP). The utilization of a random forest model incorporating these descriptors yielded promising results in the prediction of reaction yields in Pd‐catalyzed Buchwald–Hartwig amination reactions. The model achieved an impressive R2 value of 0.943. Data preprocessing on PEMF and sorting preprocessing on physical parameters resulted in a significant reduction in data size to 259 bits PEMF+2 SPPs per prediction, much less than the two previous random forest models which utilized 480 physical parameters and 21,073 bits molecular fingerprints. Although establishing definitive correlations between SPPs and reaction yield presented challenges, our findings indicate that the presence of heavier atoms in the aryl halides may have a beneficial impact within the examined Pd‐catalyzed Buchwald–Hartwig amination reactions, as compared to their analogues. [ABSTRACT FROM AUTHOR]

Amine dehydrogenases (AmDHs) are NAD(P)H‐dependent oxidoreductases that catalyze the reductive amination between carbonyl compounds and ammonia as the amine donor yielding valuable amines, typically with excellent enantioselectivity. While nature has provided enzymes with inherent AmDH activities, protein engineering techniques allowed researchers to expand the toolbox of available AmDHs, extend their substrate scope, improve their catalytic activities and stability under synthetically relevant conditions and even enable new reactivity concepts. The biocatalytic synthesis of amines using AmDHs has matured to a point where hundreds of aldehydes or ketones, of varying steric demands and bearing diverse functional groups, can be efficiently transformed. This review offers an overview of the available AmDHs and their substrate spectrum, covering from structural and evolutionary analyses to diverse methods employing these enzymes. Depending on the catalytic activities of other enzymes as reaction partners, AmDHs were applied in kinetic resolution (KR) and deracemization processes, cascade reactions for the amination of alcohols and alkenes or for the synthesis of amines and amino alcohols featuring multiple stereogenic centers. Moreover, the synthetic potential of AmDHs in novel pathways, such as the synthesis of secondary amines or alcohols, presents exciting opportunities for expanding their catalytic repertoire. [ABSTRACT FROM AUTHOR]

Developed here is a highly fluorescent organic N,O bidentate BF2 complex from isoxazole in the presence of a Ru(II) catalyst. Herein, the complexation proceeds via a selective N–O cleavage of the isoxazole ring. The complex shows absorption (λmax,abs) in the range of 352–363 nm with an extinction coefficient (ε) in the range of 8000–64 000 M−1 cm−1, and fluorescence emission (λmax,em) in the range of 413–485 nm with a Stokes shift of 61–125 nm having quantum yield up to 33%. Apart from the solution state, the solid BF2 complex 2u exhibits absorption at 405 nm and strong fluorescence emission at 550 nm with a quantum yield of 26.9%. [ABSTRACT FROM AUTHOR]

We report facile and versatile procedures for the synthesis of exo - and endo -isomeric spirocyclic hybrids of pharmacophoric (1 R ,5 S)-8-azabicyclo[3.2.1]octane (nortropane) and 1,3-oxazinan-2-one fragments. Our approach consists of the hydrocyanation of endo - and exo -isomeric N -Cbz-protected nortropane-3-spiroepoxides, the reduction of hydroxy nitriles into amino alcohols, the synthesis of N -alkylated amino alcohols via reductive amination, the spirocyclization of the amino alcohols, N -alkylation of the unsubstituted 1,3-oxazinan-2-one fragment in the spiro compounds, and removal of the Cbz protecting groups. [ABSTRACT FROM AUTHOR]

This article explores the synthesis of new amide derivatives of the sesquiterpene aryl-himachalene, a compound found in Atlas cedar oil. The researchers successfully synthesized several amide derivatives using different reaction conditions and acyl chlorides, with good yields. The results highlight the potential for using renewable and readily available natural resources in the production of valuable molecules. The document also provides a general procedure for synthesizing amides and includes data on the yields, physical properties, and analysis of the synthesized amides. The authors declare no conflicts of interest. [Extracted from the article]

Sulfinamidines are promising aza‐SIV chiral building blocks in asymmetric synthesis and drug discovery. However, no report has documented their enantioselective synthesis. Here we present an enantioselective synthesis of sulfinamidines via electrophilic amination of sulfenamides using an enantiopure N−H oxaziridine. The resulting enantiomerically enriched primary sulfinamidines are configurationally stable at 90 °C in solution and show remarkable stability against organic acids and bases under non‐aqueous conditions. We also demonstrate a one‐pot, three‐component, enantioselective synthesis of sulfinamides using N−H oxaziridine reagents. [ABSTRACT FROM AUTHOR]

In the presence of 1 mol % of a chiral iron porphyrin catalyst, various 3‐arylmethyl‐substituted 2‐quinolones and 2‐pyridones underwent an enantioselective amination reaction (20 examples; 93–99 % ee). The substrates were used as the limiting reagents, and fluorinated aryl azides (1.5 equivalents) served as nitrene precursors. The reaction is triggered by visible light which allows a facile dediazotation at ambient temperature. The selectivity of the reaction is governed by a two‐point hydrogen bond interaction between the ligand of the iron catalyst and the substrate. Hydrogen bonding directs the amination to a specific hydrogen atom within the substrate that is displaced by the nitrogen substituent either in a concerted fashion or by a rebound mechanism. [ABSTRACT FROM AUTHOR]

In this study, a novel approach for the tertiary α‐alkylation of ketones using alkanes with electron‐deficient C─H bonds is presented, employing a synergistic catalytic system combining inexpensive copper salts with aminocatalysis. This methodology addresses the limitations of traditional alkylation methods, such as the need for strong metallic bases, regioselectivity issues, and the risk of over alkylation, by providing a high reactivity and chemoselectivity without the necessity for pre‐functionalized substrates. The dual catalytic strategy enables the direct functionalization of C(sp3)─H bonds, demonstrating remarkable selectivity in the presence of conventional C(sp3)─H bonds that are adjacent to heteroatoms or π systems, which are typically susceptible to single‐electron transfer processes. The findings contribute to the advancement of alkylation techniques, offering a practical and efficient route for the construction of C(sp3)─C(sp3) bonds, and paving the way for further developments in the synthesis of complex organic molecules. [ABSTRACT FROM AUTHOR]

Herein, the use of economically and environmentally friendly bis(pinacolato)diboron (B2Pin2) is described as a non‐metallic reductant in mediating Ni‐catalyzed C(sp3)–C(sp2) reductive cross‐coupling of alkyl electrophiles with aryl/vinyl halides. This method exhibits excellent suitability for heteroaryl halides and alkyl halides/Katritzky salts. The present study is compatible with an in situ halogenation of alcohol method, allowing for selective mono‐functionalization of diols and bio‐relevant alcohols (e.g., carbohydrates). The use of B2Pin2 shows potential for easy scalability without introducing additional metal impurities into the products. It is observed for the first time in the realm of cross‐electrophile coupling chemistry that B2Pin2 can sever as a reductant to reduce NiII to Ni0. This mechanistic insight may inspire the development of new reductive bond‐forming methodologies that can otherwise be difficult to achieve with a metal reductant. [ABSTRACT FROM AUTHOR]

N-Substituted 5-(hydroxymethyl)-2-furfuryl amines have been obtained through the reductive amination of 5-hydroxymethylfurfural (HMF) with a variety of primary amines using a non-noble metal catalyst based on monodisperse Co nanoparticles covered by a thin carbon layer. The Co@C catalyst was highly active, selective and stable, allowing us to perform the reductive amination of HMF under very mild reaction conditions (60 °C and 4 bar H2) using ethanol as a green solvent and achieve the corresponding amino-alcohol in yields ranging from 80 to 99%. Moreover, the reaction was extended to other furanic aldehydes with excellent success. Furthermore, in order to synthesize amino-ester derivatives, precursors of ammonium salt-based surfactants, the reductive amination of HMF with methylamine was coupled with the selective esterification of the hydroxymethyl group of the furan ring with fatty acids using lipase CALB (Novozym 435) as a biocatalyst in 2-methyltetrahydrofuran as a green and enzyme compatible solvent, achieving practically total conversion to the corresponding amino-esters. The process was implemented in flow reactors by combining two consecutive fixed bed reactors, achieving a global yield of the amino-ester derivative of 85%, which was maintained over 86 h of operation. [ABSTRACT FROM AUTHOR]

Catalytic transformation of renewable biomass into value-added chemicals is an appealing strategy to upgrade biomass resources. Due to the presence of abundant oxygen-containing groups such as hydroxyl and aldehyde, biomass and its derived platform molecules have been served as ideal starting feedstock to synthesize valuable N-containing chemicals through reductive amination. In this mini review, we overviewed the recent advances in the reductive amination of several key bio-platform molecules including hydroxyl carboxylic acids, furfural, 5-hydroxylmethyl furfural and levulinic acid, with a focus on the production of amino acids, furan amines and pyrrolidones using thermocatalysis, electrocatalysis or photocatalysis. Moreover, the functions of active sites and the reaction mechanisms in different catalytic systems are discussed to get insights into the key factors in the reductive amination of biomass resources. [ABSTRACT FROM AUTHOR]

[Display omitted] Hard carbon as a negative electrode material for sodium-ion batteries (SIBs) has great commercial potential and has been widely studied. The sodium-ion intercalation in graphite domains and the filling of closed pores in the low voltage platform region still remain a subject of controversy. We have successfully constructed hard carbon materials with a pseudo-graphitic structure by using polymerizable p -phenylenediamine and dichloromethane as carbon sources. This was achieved by a halogenated amination reaction and oxidative polymerization. It was found that the capacity of hard carbon materials mainly originates from intercalation into graphite domains. The study found that the prepared hard carbon could store 339.33 mAh g−1 of sodium in a reversible way at a current density of 25 mA g−1, and it had an initial coulomb efficiency of 80.23%. It even maintained a reversible sodium storage capacity of 125.53 mAh g−1 at a high current density of 12.8 A g−1. Based on the analysis of hard carbon structure and electrochemical performance, it was shown that the materials conform with an "adsorption-intercalation" mechanism for sodium storage. [ABSTRACT FROM AUTHOR]

A seven-step ex-chiral-pool synthesis of optically active 4-alkylidenetetrahydroisoquinolines was developed. Starting from 6-bromopiperonal and (S)-serine esters, N -benzylation via reductive amination gave enantiopure N -piperonyl serine esters. Subsequent NH and OH protection delivered defined (S)-serine building blocks. The best results to achieve the conversion into the corresponding serinal were obtained via a two-step sequence of NaBH4 /LiCl reduction and subsequent TEMPO oxidation. Then, chain elongation using the Masamune–Roush variant of the Horner olefination afforded ethyl (E)-4-(N -6-bromopiperonyl)-substituted pentenoates in high yields. Intramolecular Heck cyclization employing the Herrmann–Beller catalyst enabled generation of enantiopure 4-(2-ethoxycarbonylmethylidene)tetrahydroisoquinoline building blocks in high Z -selectivity. Subsequent selected functional group transformations gave carbinols and lactones, which can be used as key intermediates in crinane alkaloid total syntheses. [ABSTRACT FROM AUTHOR]

An efficient and scalable Buchwald‐Hartwig amination towards the synthesis of the API candidate 4‐((2‐Chlorophenyl)amino)‐6‐((6‐methylpyridin‐2‐yl)amino)nicotinamide as a JAK inhibitor was described. The process was developed using water and a water‐miscible co‐solvent. It was facilitated by the benign by design surfactant TPGS‐750‐M, that promoted the robust and reliable preparation of our target compound in high yields, with improved reaction profile and via an operationally simple protocol. [ABSTRACT FROM AUTHOR]

Nitrogen containing compounds like chiral amines have been widely used in synthetic medicines, biomass, and fine chemical products because of their particularly valuable motifs and exceedingly broad range of functionality. Enantioconvergent synthesis of chiral amines has high atomic economy and enantioselectivity with theoretically 100 % yield of enantioenriched products. In this concept article, we hope to provide a further understanding of chiral amines enantioconvergent synthesis methodology with an introduction of recent progresses in enantioconvergent amination reactions catalyzed by early transition metals and facilitate the development of enantioconvergent C(sp3)−N coupling for benign and efficient preparation of highly valuable chiral nitrogen‐containing units. [ABSTRACT FROM AUTHOR]

A gold(I)‐catalyzed intramolecular dehydrative amination method has been developed to synthesize diverse cyclic sulfamides efficiently. Reactions proceed smoothly at room temperature using a combination of (IPr)AuCl (5 mol%) and AgBF4 (5 mol%). This method showcases a broad substrate scope, encompassing challenging seven‐membered ring structures, and exhibits functional group compatibility. Moreover, the reaction demonstrates high stereoselectivity, allowing the synthesis of enantiomerically enriched cyclic sulfamides from chiral secondary allylic alcohols. The synthesized cyclic sulfamides serve as valuable intermediates for generating 1,3‐diamines. This approach provides an improved route for cyclic sulfamide synthesis and a strategic entry point for obtaining essential 1,3‐diamine derivatives. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Green Chemistry," published by The Royal Society of Chemistry. It highlights the articles and research papers included in the issue, covering topics such as sustainable water treatment, lignocellulose pretreatment, and biomass valorization. The journal aims to promote cutting-edge research for a greener and more sustainable future. [Extracted from the article]

Catalytic olefin hydroamination reactions are some of the most atom‐economical transformations that bridge readily available starting materials–olefins and high‐value‐added amines. Despite significant advances in this field over the last two decades, the formal hydroamination of nonactivated aromatic compounds remains an unsolved challenge. Herein, we report the extension of olefin hydroamination to aromatic π‐systems by using arenophile‐mediated dearomatization and Cu‐catalysis to perform 1,2‐hydroamination on nonactivated arenes. This strategy was applied to a variety of substituted arenes and heteroarenes to provide general access to structurally complex amines. We conducted DFT calculations to inform mechanistic understanding and rationalize unexpected selectivity trends. Furthermore, we developed a practical, scalable desymmetrization to deliver enantioenriched dearomatized products and enable downstream synthetic applications. We ultimately used this dearomative strategy to efficiently synthesize a collection of densely functionalized small molecules. [ABSTRACT FROM AUTHOR]

Organic electrochemistry is currently experiencing an era of renaissance, which is closely related to the possibility of carrying out organic transformations under mild conditions, with high selectivity, high yields, and without the use of toxic solvents. Combination of organic electrochemistry with alternative approaches, such as photo‐chemistry was found to have great potential due to induced synergy effects. In this work, we propose for the first time utilization of plasmon triggering of enhanced and regio‐controlled organic chemical transformation performed in photoelectrochemical regime. The advantages of the proposed route is demonstrated in the model amination reaction with formation of C−N bond between pyrazole and substituted benzene derivatives. Amination was performed in photo‐electrochemical mode on the surface of plasmon active Au@Pt electrode with attention focused on the impact of plasmon triggering on the reaction efficiency and regio‐selectivity. The ability to enhance the reaction rate significantly and to tune products regio‐selectivity is demonstrated. We also performed density functional theory calculations to inquire about the reaction mechanism and potentially explain the plasmon contribution to electrochemical reaction rate and regioselectivity. [ABSTRACT FROM AUTHOR]

Furfural is a well-recognized biomass platform. Hydrogenation and reductive amination of furfural are two principal routes in the valorization of this compound. In both reactions, the presence of reducible species (SMSI effect) and acid sites could favor the selectivity toward some interesting products. Both conditions could be obtained using metal particles supported on reducible mixed oxides. In this work, we investigate the use of Pt/Nb2O5-Al2O3 catalysts for the hydrogenation and reductive amination of furfural at distinct Nb2O5 contents. A decaniobate salt was used as a precursor of Nb2O5. The solids were reduced at 500 °C to assure the migration of reducible NbOx species. The solids were characterized by XRD, Raman spectroscopy, HR-TEM, N2-physisorption, NH3-TPD and Pyr-DRIFTS. The results showed that higher Nb2O5 loadings led to a lower distribution of Al2O3 and Pt, favoring the catalysts' acidity. This fact implies that large particle size and the presence of Nb2O5 islands favor the formation of furfuryl alcohol but have a detrimental effect on the amine formation in the reductive amination of furfural. [ABSTRACT FROM AUTHOR]

An efficient catalytic asymmetric dearomatizing amination of 2-naphthols and phenols catalyzed by N,N′-dioxide-copper(I) complex as a chiral catalyst was presented. A variety of optically active β-naphthalenone compounds with a nitrogen-containing quaternary carbon stereocenter were obtained with high yield and enantioselectivity under mild reaction conditions. Mechanistic studies indicated that this Csp2–N dearomatizing coupling proceeds via 1,3-reductive elimination of phenolate-CuIII-amino intermediate in five-membered ring transition states. The origin of enantioselectivity has also been elucidated based on density functional theory calculations. [ABSTRACT FROM AUTHOR]

The formation of carbon‐nitrogen bonds holds paramount importance in the realm of synthetic organic chemistry, finding extensive applications in the synthesis of pharmaceuticals, agrochemicals, and organic materials. Herein, we describe a novel EDA complex mediated, metal‐ and photocatalyst‐free, visible‐light‐initiated direct C‐3 amination of biologically important, quinoxalin‐2(1H)‐one moiety. The key to the success lies in the formation of a photoactivated electron donor‐acceptor complex between quinoxalin‐2(1H)‐one and amine, which undergo subsequent electron transfer reaction to effect the desired transformation. A diverse array of 3‐aminoquinoxalin‐2(1H)‐ones were prepared employing this process and the yields are up to 87%. This work represents a significant advancement toward a more environmentally friendly and efficient approach, characterized by mild reaction conditions and a high atom economy. [ABSTRACT FROM AUTHOR]

Here we present a hybrid catalytic pathway for efficient synthesis of 5-aminomethyl-2-furancarboxylic acid (AMFC), a bio-based nylon-6 analogue monomer, from 5-hydroxymethylfurfural (HMF). This method combines homogeneous-catalyzed selective oxidation of HMF to 5-formyl-2-furancarboxylic acid (FFCA) with heterogeneous-catalyzed reductive amination using ammonia as the nitrogen source. Through this relay strategy, we achieve significant enhancements in overall efficiency, resulting in isolation yields of up to 92% for highly selective and scalable AMFC production from HMF. [ABSTRACT FROM AUTHOR]

In recent years, mechanochemistry has become recognized as an efficient, practical, and sustainable alternative for chemical synthesis. Adhering to the principles of green chemistry, mechanochemistry enables solvent-free, faster, and energy-efficient reactions, thereby reducing waste production and enhancing atom economy. Herein, we present a new nickel-catalyzed mechanochemical High Throughput Experimentation (HTE) amination protocol enabled by Resonant Acoustic Mixing (RAM). The developed C–N cross-coupling reactions avoid possible contamination, scaling-up challenges, and parallel reaction limitations by applying an accelerated screening and optimization protocol. The reduced amount of solvents in the reactions and the minimal amount of reagents required highlight the advantages of our approach over most common solvent-based reactions, aligning with the principles of sustainability and resource efficiency. Furthermore, the mechanochemistry methodology demonstrates seamless scalability to a multigram scale without additional optimizations, emphasizing its potential for streamlined, environmentally friendly, and large-scale industrial production. [ABSTRACT FROM AUTHOR]

Alkylamine structures represent one of the most functional and widely used in organic synthesis and drug design. However, the general methods for the functionalization of the shielded and deshielded alkyl radicals remain elusive. Here, we report a general deoxygenative amination protocol using alcohol-derived carbazates and nitrobenzene under electrochemical conditions. A range of primary, secondary, and tertiary alkylamines are obtained. This practical procedure can be scaled up through electrochemical continuous flow technique. Secondary arylalkylamines represent important building blocks for organic synthesis, and as such their straightforward synthesis from readily available chemicals remains a priority in organic chemistry. Here, the authors report a synthesis of arylalkylamines from nitroarenes and carbazates via paired electrolysis. [ABSTRACT FROM AUTHOR]

An operationally simple approach to azolo[4,5‐b]quinolines based on the condensation of 2‐aminobenzaldehydes with various azolones is developed. A series of 22 compounds was synthesized typically in good yields (40–92 %). [ABSTRACT FROM AUTHOR]

This work describes a novel iron‐catalysed approach for the synthesis of aryl‐substituted benzimidazoles and benzoxazoles. The methodology employs reductive carbonylation using readily available aryl iodides and aryl amines as precursors, with carbon monoxide serving as the efficient carbonyl source. The reaction proceeds under mild conditions with the addition of hydrosilanes and bases. Notably, aryl aldehydes are generated in situ from the aryl iodides, which subsequently react with o‐phenylenediamine or 2‐aminophenol to afford the desired products in high yields. The structures of the synthesized benzimidazoles and benzoxazoles were confirmed using 1H and 13C NMR spectroscopy and mass spectrometry. [ABSTRACT FROM AUTHOR]

Reductive amination by amine dehydrogenases is a green and sustainable process that produces only water as the by-product. In this study, a continuous flow process was designed utilizing a packed bed reactor filled with co-immobilized amine dehydrogenase wh84 and glucose dehydrogenase for the highly efficient biocatalytic synthesis of chiral amino alcohols. The immobilized amine dehydrogenase wh84 exhibited better thermo-, pH and solvent stability with high activity recovery. (S)-2-aminobutan-1-ol was produced in up to 99% conversion and 99% ee in the continuous flow processes, and the space-time yields were up to 124.5 g L-1 d-1. The continuous reactions were also extended to 48 h affording up to 91.8% average conversions. This study showcased the important potential to sustainable production of chiral amino alcohols in continuous flow processes. [ABSTRACT FROM AUTHOR]

The direct functionalization of quinones has always fascinated research communities due to their biological and redox activities and subsequent application. Quinone motifs play a vital role as precursors for many bioactive compounds and materials; hence, many ingenious methodologies have been elaborated for exploring these units. A significant part of the synthetic strategies towards the functionalized quinones has been achieved by installing substituents on hydroquinones, phenols, or quinone itself by different oxidative coupling reactions via radical pathways with or without the utilization of metal catalysts. The functionalization of simple quinones via direct C−H bond remains challenging due to their inherited electronic nature and high bond dissociation energy. This review article summarizes the recent advancement made for functionalized quinones through direct functionalization of simple quinones. Our primary focus will be on the synthetic approaches and mechanistic pathways of these reactions that have appeared in the last two decades, along with a short historical importance of the quinone family. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive overview of various methods for the synthesis of substituted naphthalene derivatives. Naphthalene is a versatile organic compound with applications in materials chemistry, electronics, and medicine. The synthesis of naphthalene involves metal-catalyzed reactions, such as palladium-catalyzed carboannulation, and yields derivatives with diverse substituents. These derivatives have medicinal importance and exhibit a wide range of therapeutic activities. The article discusses different metal-catalyzed reactions, their mechanisms, and examples of reactions. It also highlights the need for more environmentally friendly approaches to naphthalene synthesis. [Extracted from the article]

Chiral amines are valuable building blocks in the manufacture of agrochemicals, pharmaceuticals, natural products, fine chemicals, functional materials among others. Compared to asymmetric hydrogenation of imines/enamides and biocatalytic/organocatalytic asymmetric reductive amination, transition metal catalyzed direct asymmetric hydrogenative amination reactions (DAHA) using molecular dihydrogen as the reductant are highly economical, atom and/or step‐efficient and thus attractive for researchers from both industry and academia. In previous reviews, catalysts/methods development, applications in synthesis of pharmaceuticals and [N] source were summarized and discussed. In this review, we summarize and discuss the ketone substrates scope upon utilizing the state‐of‐the‐art transition metal catalysts. The substrate limitations, potential applications and key mechanisms are also critically concluded. [ABSTRACT FROM AUTHOR]

7‐Aminoindoles are important synthetic intermediates to a broad range of bioactive molecules. Transition metal‐catalyzed directed C−H amination is among the most straightforward route for their synthesis, whereas methods that could directly incorporate an NH2 group in a highly selective manner remains elusive. Moreover, there is still high demand for the development of earth‐abundant metal catalysis for such attractive reactivity. We present here the first C‐7 selective NH2 amination of indoles through a directed homolytic aromatic substitution (HAS) with iron‐aminyl radical. The reaction exhibits broad substrate scope, tolerates variety of functional groups, and is readily scalable with catalyst loading down to 0.1 mol % and turnover number (TON) up to 4500. [ABSTRACT FROM AUTHOR]

The cooperation between a geometrically constrained, highly electrophilic phosphorus(V) center, and an electronically rich tetradentate bis(amidophenolate) ligand enables the cleavage of the C＝O bond from typical aldehydes and ketones delivering iminio phosphoramidate species. The amphiphilic nature of these products, which is demonstrated through their reaction with typical Lewis acids and bases, enables their use as a mild source of silylium cations from silanes, allowing the selective reductive coupling of aldehydes to ethers under catalytic conditions. [ABSTRACT FROM AUTHOR]

A transition metal‐free Se‐catalyzed C−H amination protocol for α’‐amination of enol derivatives has been developed. This reaction can be used to functionalize a wide variety of oxygen‐ and halogen‐substituted alkenes spanning a vast range of nucleophilicities, giving α’‐aminated enol derivatives with high regioselectivity. Amination of E/Z mixtures of alkenes proceeds stereoconvergently to give the (Z)‐enol derivatives exclusively. Mechanistic studies revealed that the relative reactivity and α’‐regioselectivity of these transformations is determined by substantial resonance donation to the heteroatom‐bound carbon in the transition state. These products participate in traditional reactions of enol derivatives, allowing for efficient functionalization of both α‐ and α’‐positions from a single enol derivative with high diastereocontrol. [ABSTRACT FROM AUTHOR]

As the global surfactant market continues to expand, there is an increasing need to develop bio‐based alternatives in the shift towards a circular economy. This study focuses on the synthesis of polar, amphoteric, amine‐oxide surfactants starting from biomass‐derived monosaccharides and demonstrating their potential in various applications. The synthesis involved a reductive amination of the sugars with an alkylamine and formaldehyde followed by oxidation to produce N‐oxide surfactants. These bio‐based surfactants exhibited promising properties, including high solubility, foamability, surface tension reduction, and critical micelle concentration. In particular, N‐GalA1.10 and N‐GalA1.12 showed comparable performance to commercial surfactants. Furthermore, these bio‐based surfactants demonstrated significantly lower skin irritation potential when compared to petrochemical‐derived counterparts like sodium laureth sulfate (SLES), making them potentially suitable for personal care products. The biodegradability assessment revealed that N‐GalA1.12 exhibited good biodegradation, indicating its potential environmental compatibility. In conclusion, this study highlights the potential of bio‐based N‐oxide surfactants derived from monosaccharides as sustainable and skin‐friendly alternatives to traditional amphoteric surfactants, like cocamidopropyl betaine (CAPB). [ABSTRACT FROM AUTHOR]

The switchable synthesis of 3-aminoindolines and 2′-aminoaryl acetic acids from the same substrates, 3-azido-2-hydroxyindolines, was developed through denitrogenative electrophilic amination of Grignard reagents. The key to success is the serendipitous discovery that the reaction conditions, including solvents and reaction temperature, can affect the chemoselectivity. It is noteworthy that isotope-labeling experiments revealed the occurrence of the aziridine intermediate in the production of 2′-aminoaryl acetic acids. [ABSTRACT FROM AUTHOR]

Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen‐containing molecules. Here, we report the sustainable production of amino acids from biomass‐derived hydroxy acids with high activity under visible‐light irradiation and mild conditions, using atomic ruthenium‐promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu−1 ⋅ h−1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O−H bond dissociation of the α‐hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique "double activation" mechanism of both the CH−OH and CH3−CH−OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine. [ABSTRACT FROM AUTHOR]

This document discusses the development of a fluorescent probe, called compound 22, for the cannabinoid CB2 receptor. The probe was designed to visualize the receptor without the need for a toxic copper-mediated reaction. It demonstrated reasonable affinity for the CB2 receptor, selectivity over the CB1 receptor, and acted as an inverse agonist. The study also highlights the potential impact of small structural changes in compounds on the functional behavior of the CB2 receptor. This research contributes to the development of CB2 receptor-selective drugs for various applications. [Extracted from the article]

Polytetrafluoroethylene (PTFE) and, by extension, fluoropolymers are ubiquitous in science, life, and the environment as perfluoroalkyl pollutants (PFAS). In all cases, it is difficult to transform these materials due to their chemical inertness. Herein, we report a direct amination process of PTFE and some fluoropolymers such as polyvinylidene fluoride (PVDF) and Nafion by lithium alkylamide salts. Synthesizing these reactants extemporaneously between lithium metal and an aliphatic primary di- or triamine that also serves as a solvent leads to the rapid nucleophilic substitution of fluoride by an alkylamide moiety when in contact with the fluoropolymer. Moreover, lithium alkylamides dissolved in suitable solvents other than amines can react with fluoropolymers. This highly efficient one-pot process opens the way for further surface or bulk modification if needed, providing an easy, inexpensive, and fast experiment protocol on large scales. [ABSTRACT FROM AUTHOR]

Lignin is an inexpensive bio-adsorbent and has many applications in the adsorption of heavy metals. The structure and size of the lignin molecular chain affect its properties. Introducing of amino functional groups to the structure of lignin can improve its physical and chemical properties and increase its reactivity and adsorption power. Lignin cross-linking also improves its performance and adsorption characteristics. In the first step, lignin as a black liquor was extracted and purified from the waste of the wood factory. The lignin was then reacted with phenol to obtain lignophenol. The obtained lignophenol was then aminated via reacting with the ethylene diamine. Finally, in order to increase the strength of the adsorbent structure and prevent the dissolution of the adsorbent at low pHs (suitable for adsorption), 37% aqueous formaldehyde was added to the aminated lignin, from which aminated and cross-linked lignophenol was then obtained. Different types of lignins including lignin, lignophenol and amine-functionalized (branched or cross-linked) lignophenol were well synthesized and identified. The results of FT-IR spectrum showed that the amine functional groups were well attached to the lignophenol branches and the lignophenol was converted to the amino-containing lignophenol. Also, the results of acid–base titration and 11HNMR show that phenol was successfully bonded onto the lignin and amine functional groups were observed in lignin structure. The results of acid–base titration, elemental analysis and zeta potential tests also confirmed amination of lignophenol. [ABSTRACT FROM AUTHOR]

Using palladium-catalyzed arylation of (S)-2,2′-diamino-1,1′-binaphthalene (BINAM) with the halogen derivatives of naphthalene, anthracene, and anthraquinone, the corresponding N,N′-diaryl derivatives were synthesized. The dependence of the yields of the compounds on the structure of the initial halogen derivatives was shown. The synthesized compounds were studied in fluorescent enantioselective detection of amino alcohols. The synthesized derivatives demonstrate a response in the case of complex formation with some amino alcohols, but the response is most pronounced for the derivative with anthraquinone substituents. This detector can recognize enantiomers of leucinol, 2-phenylglycinol, and prolinol by different changes in the fluorescence enhancement in the presence of opposite optical isomers. In the case of 2-amino-1-propanol, fluorescence enhancement is observed only in the presence of the (S)-isomer. [ABSTRACT FROM AUTHOR]