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AbstractThe aza-Michael addition reaction of primary and secondary amines to α,β-unsaturated olefins viz; acrylonitrile, phenyl vinyl sulfone and dimethyl maleate has been carried out using 5–10 mol% Co(NO3)2.6H2O as a catalyst in t-BuOMe at 80–100 °C, giving rise to the desired β-aminocarbonyl compounds or sulfones in moderate to good yields. A wide range of aromatic amines, even those bearing electron withdrawing groups could be added to activated olefins via this strategy. Addition of (hetero)aromatic amines were also feasible, while in case of 2-aminopyridine the reaction was found to be effective only when AgOTf was added along with the catalyst. The aliphatic amines; benzylamine, dibenzylamine, di-n-butylamine were also smoothly added to acrylonitrile and phenyl vinyl sulfone. The methodology describes cobalt(II) nitrate as an eco-friendly, cheap and shelf available catalyst suitable for performing the Michael-type hydroamination reactions. [ABSTRACT FROM AUTHOR]

Electrosynthesis represents a dynamic field in organic chemistry for the development of important and selective reactions. Among the most interesting electrosynthetic transformations is the non‐directed arene C−H amination. Despite increasing reports, the quest for a non‐directed electrochemical arene C−H amination capable of accommodating a wide range of arenes and amines with high site‐selectivity remains ongoing. Non‐directed electrochemical C−H amination presents a metal‐free, mild approach for synthesizing complex aminated compounds of interest in pharmaceuticals and natural products. This concept aims to introduce the concept of non‐directed electrochemical C−H amination and provide an overview of the recent advances in the field as well as the current limitations and potential directions. [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]

This document provides information on the synthesis and characterization of various compounds, including β-aminonitriles, β-amino sulfones, and dimethyl aspartates. The compounds were synthesized using lanthanoid triflates Yb(OTf)3 and Tb(OTf)3 as catalysts and the reactions were optimized for yield. The document also includes spectroscopic data, such as melting points and NMR spectra, for the compounds. The data presented in the document match those previously reported in the literature. The document acknowledges the facilities used for the research and dedicates the work to the late Prof. Ibrahim Ibnusaud. [Extracted from the article]

Reductive N‐11C‐methylation using [11C]formaldehyde and amines has been used to prepare N‐11C‐methylated compounds. However, the yields of the N‐11C‐methylated compounds are often insufficient. In this study, we developed an efficient method for base‐free reductive N‐11C‐methylation that is applicable to a wide variety of substrates, including arylamines bearing electron‐withdrawing and electron‐donating substituents. A 2‐picoline borane complex, which is a stable and mild reductant, was used. Dimethyl sulfoxide was used as the primary reaction solvent, and glacial acetic acid or aqueous acetic acid was used as a cosolvent. While reductive N‐11C‐methylation efficiently proceeded under anhydrous conditions in most cases, the addition of water to the reductive N‐11C‐methylation generally increased the yield of the N‐11C‐methylated compounds. Substrates with hydroxy, carboxyl, nitrile, nitro, ester, amide, and phenone moieties and amine salts were applicable to the reaction. This proposed method for reductive N‐11C‐methylation should be applicable to a wide variety of substrates, including thermo‐labile and base‐sensitive compounds because the reaction was performed under relatively mild conditions (70°C) without the need for a base. [ABSTRACT FROM AUTHOR]

We report a one-step synthesis of trifluoromethyl-substituted di(pyridin-2-yl)amine-based ligands. N-(hetero)aryl-substituted bis(5-(trifluoromethyl)pyridin-2-yl)amines were obtained from 2-bromo-5-(trifluoromethyl)pyridine and corresponding aromatic amines via Pd-catalyzed amination reaction in the presence of a Pd(dba)2/BINAP catalytic system. Four new ligands were prepared in good to high yields and characterized by NMR, IR spectroscopies and mass spectrometry. The structure of one of the products was additionally supported by X-ray analysis. [ABSTRACT FROM AUTHOR]

Cyclopropylmethyl sulfides react with N‐fluorosulfonimide (NFSI) or molecular iodine, enabling C−S cleavage to generate cyclopropylcarbinyl cations, which evolve through cyclopropane ring‐opening reactions into homoallyl cations suitable to react with nucleophiles present in the reaction media. This desulfurative cleavage of cyclopropylmethyl thioethers under non‐acidic conditions facilitates homoallylation of N‐based nucleophiles such as alkyl or aryl amines as well as sulfonimides through a one‐pot protocol in one or two steps depending on the nucleophile. The reaction is initiated by a halogen‐sulfur bond that causes C−S bond cleavage. Moreover, the reaction with iodine proceeds through homoallyl iodide intermediates. [ABSTRACT FROM AUTHOR]

Arylamines, serving as crucial building blocks in natural products and finding applications in multifunctional materials, are synthesized on a large scale via an electrophilic nitration/reduction sequence. However, the current methods for aromatic C–H amination have not yet attained the same level of versatility as electrophilic nitration. Here we show an extensively investigated transition metal-free and regioselective strategy for the amination of nitrobenzenes, enabling the synthesis of 4-nitro-N-arylamines through C(sp2)-H/N-H cross-coupling between electron-deficient nitroarenes and amines. Mechanistic studies have elucidated that the crucial aspects of these reactions encompass the generation of nitrogen radicals and recombination of nitrobenzene complex radicals. The C(sp2)-N bond formation is demonstrated to be highly effective for primary and secondary arylamines as well as aliphatic amines under mild conditions, exhibiting exceptional tolerance towards diverse functional groups in both nitroarenes and amines (>100 examples with yields up to 96%). Notably, this C(sp2)-H/N-H cross-coupling exhibits exclusive para-selectivity. Direct radical C–H amination strategies have exhibited innovation, but challenges remain with C–H amination of electron-poor nitroarenes due to the essence of the electron-deficient nitrogen radical. Herein, the authors report a transition metal-free dehydrogenative C(sp2)-H/N-H cross-coupling between electron-poor nitroarenes and amines. [ABSTRACT FROM AUTHOR]

This study describes the palladium‐catalyzed chemoselective amination of chloro(hetero)aryl triflates in the C−Cl bond for the first time. A newly designed and synthesized alkyl‐pyrazole‐based phosphine ligand, L26 (BirdPhos), which is featured with the pyrazole ligand core and the cyclohexyl group at the C3 and C5 positions, was key to the success of this reaction. A variety of chloro(hetero)aryl triflates coupled with aromatic, aliphatic, and heterocyclic amines smoothly afforded the corresponding products up to 97% yields with general chemoselectivity (>99%) in the C−Cl bond. Drug analogs were also synthesized via the chemoselective intermolecular amination. This study attempts to investigate the structure‐activity relationship of this new class of ligand through experimental and density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Six novel palladium N-heterocyclic carbene complexes bearing different ancillary ligands such as pyridine, 1-methylimidazole, 4,5-dimethylthiazole and 3-bromoquinoline have been successfully prepared in a one-step process. These complexes were used as pre-catalysts in the Buchwald–Hartwig amination of cyclic secondary amines with aryl chlorides. A range of cyclic secondary amines were tolerated to a wide variety of aryl chlorides in presence of 1 mol% catalyst loading under mild conditions. Under the tested reaction conditions, the expected N-arylamines were obtained in moderate to high yields. The results showed that these novel palladium complexes are effective catalysts for the Buchwald–Hartwig amination. [ABSTRACT FROM AUTHOR]

In this report, we describe the use of amino‐λ3‐iodanes in the electrophilic amination of arylboronic acids and boronates. Iodine(III) reagents with transferable amino groups, including one with an NH2 group, were synthesized and used in the amination, allowing the synthesis of a wide range of primary and secondary (hetero)arylamines. Mechanistic studies by DFT calculations indicate that the reaction proceeds through an electrophilic amination process from a tetravalent borate complex with a B−N dative bond. [ABSTRACT FROM AUTHOR]

Aliphatic allylic amines are common in natural products and pharmaceuticals. The oxidative intermolecular amination of C(sp3)-H bonds represents one of the most straightforward strategies to construct these motifs. However, the utilization of widely internal alkenes with amines in this transformation remains a synthetic challenge due to the inefficient coordination of metals to internal alkenes and excessive coordination with aliphatic and aromatic amines, resulting in decreasing the reactivity of the catalyst. Here, we present a regioselective Cu-catalyzed oxidative allylic C(sp3)-H amination of internal olefins with azodiformates to these problems. A removable bidentate directing group is used to control the regiochemistry and stabilize the π-allyl-metal intermediate. Noteworthy is the dual role of azodiformates as both a nitrogen source and an electrophilic oxidant for the allylic C-H activation. This protocol features simple conditions, remarkable scope and functional group tolerance as evidenced by >40 examples and exhibits high regioselectivity and excellent E/Z selectivity. The oxidative intermolecular amination of C-H bonds represents a straightforward method to construct aliphatic allylic amines. However, the utilization of widely available internal alkenes remains a synthetic challenge. Here, the authors present a regioselective Cu-catalyzed oxidative allylic C-H amination of internal olefins with azodiformates. [ABSTRACT FROM AUTHOR]

Cheap, stable and easy‐to‐handle Werner ammine salts have been known for more than a century; but they have been rarely used in organic synthesis. Herein, we report that the Werner hexammine complex [Ni(NH3)6]Cl2 can be used as both a nitrogen and a catalytic nickel source that allow for the efficient amination of aryl chlorides in the presence of a catalytic amount of bipyridine ligand under the irradiation of 390–395 nm light without the need of any additional catalysts. More than 80 aryl chlorides, including more than 20 drug molecules, were aminated, demonstrating the practicality and generality of this method in synthetic chemistry. A slow NH3 release mechanism is in operation, obviating the problem of catalyst poisoning. Still interestingly, we show that the Werner salt can be easily recovered and reused, solving the problem of difficult recovery of transition metal nickel catalysts. The protocol thus provides an efficient new strategy for the synthesis of primary aryl amines. [ABSTRACT FROM AUTHOR]

The construction of C−N bonds is considered one of the most useful reactions in synthetic chemistry due to their widespread presence in pharmaceuticals, natural products, etc. Pd‐catalyzed Buchwald–Hartwig amination (BHA) has provided the most efficient method to form (hetero)aryl amines but it required strong base and sophisticated ligands. In comparison, the combination of photocatalysis and nickel chemistry has revolutionized catalytic strategies and is emerging as a quintessence to realize BHA, termed as Ni‐metallaphotoredox BHA. To pursue a universal protocol, diverse photocatalysts were designed and employed in Ni‐metallaphotoredox BHA, and smoothly promoted C−N bond formations under irradiation of light from ultraviolet to red light, respectively. Note that the matching of photocatalyst and light was critical for success. Therefore, this review mainly focuses on the discussion of Ni‐metallaphotoredox BHA according to the irradiation light's wavelength, covering ultraviolet, purple, blue, red, and white light as well as solar light. We try to find a clue in the relationship of structure‐photophysical behaviors of photocatalysts under the same or different irradiation light. At last, current limitations and potential trends for advancing Ni‐metallaphotoredox BHA are highlighted. We deem that it could encourage chemists to continue designing suitable photocatalyst for C−N bond formations under sunlight mimicking plants' photosynthesis. [ABSTRACT FROM AUTHOR]

Objective: To aromatically aminate refined rice bran oil (RBO), a by-product of the rice agro-industry, through a chemical-enzymatic epoxidation based on Novozym 435 and p-xylylenediamine insertion. Design/Methodology/Approach: Refined RBO was epoxidized with H2O2/Novozym 435. The resulting epoxidized rice bran oil (eRBO) was functionalized with the p-xylylenediamine aromatic diamine via epoxy ring-opening (X-eRBO), using ZnCl2 as catalyst. Iodine value (IV), saponification value (SV), and oxirane oxygen content (OOC) were determined to evaluate structural changes in oils. The RBO, the eRBO, and the X-eRBO were identified using FTIR, ¹H, and 13C NMR. Results: The IV, the SV, and the OOC suggest that the synthesis of eRBO and X-eRBO were effective. The increase of molecular weight in eRBO point to the formation of ~6 epoxy rings per original triglyceride. The OOC value of X-eRBO was 22% lower than the OOC value of eRBO, implying that an effective aromatic amination was achieved. The FTIR, ¹H and 13C NMR spectroscopy analysis confirmed the epoxidation and amination of the RBO. Study Limitations/Implications: X-eRBO may be a feasible precursor for value-added products, such as crosslinked polymers or corrosion inhibitors. Findings/Conclusions: Refined rice bran oil was aromatically aminated after two stages under mild thermal conditions. This result was achieved with an epoxidation sequence with H2O2/Novozym 435, followed by functionalization with p-xylylenediamine. [ABSTRACT FROM AUTHOR]

Aryl amines are of constant interest in organic synthesis owing to their ubiquity in natural products, pharmaceuticals, and organic materials. However, C−H amination or pre‐functionalization frequently results in uncontrollable site selectivity, over activation and the generation of inseparable mixtures of regio‐isomers. Here we present a novel metal free Dötz‐type aminobenzannulation reaction that circumvents the selectivity issues inherent in aromatic chemistry, as well as the use of stoichiometric unstable organolithium reagents and toxic chromium complexes. The concept of utilizing readily available isocyanides and Morita–Baylis–Hillman (MBH) carbonates to achieve 1,1‐dipoles cross‐coupling to construct ketenimine is the key to success, which has been experimentally and computationally verified. The tandem 6π‐electrocyclization/aromatization process offers a versatile method for synthesizing functionalized anilines, fused aryl amines and fused heteroaryl amines. [ABSTRACT FROM AUTHOR]

We describe continuous-flow N-methylation with formaldehyde and H2 using heterogeneous Pd catalysts as a green synthetic method to access N-methyl amines. The catalyst exhibited excellent activity for aliphatic and aromatic amines. The developed method was also applied to sequential hydrogenation reactions to access challenging N-monomethyl amines. [ABSTRACT FROM AUTHOR]

Chiral amines are broadly used compounds in pharmaceutical industry and organic synthesis, and reductive amination reactions have been the most appreciated methods for their syntheses. However, one‐step transfer hydrogenative direct asymmetric reductive amination (THDARA) that could expand the scope, simplify the operation and eliminate the use of additives has been challenging. In this work, based on the Xiao's racemic transfer hydrogenative reductive amination in 2010 and our recent work in novel chiral pyridine ligands, chiral half‐sandwich iridium catalysts were rationally designed and synthesized. Using the optimized catalyst and azeotropic mixture of formic acid and triethylamine as the hydrogen source, a broad range of α‐chiral (hetero)aryl amines, including various polar functional groups and heterocycles, were prepared in generally high yield and enantioselectivity under mild and operationally simple conditions. Density functional theory (DFT) calculation of the catalytically active Ir−H species and the key hydride transfer step supported the chiral pyridine‐induced stereospecific generation of the iridium center, and the enantioselection by taming the highly flexible key transition structure with multiple attractive non‐covalent interactions. This work introduced a type of effective chiral catalysts for simplified approach to medicinally important chiral amines, as well as a rare example of robust enantioselective transition‐metal catalysis. [ABSTRACT FROM AUTHOR]

A one‐pot synthesis of 2,3,4‐unprotected β‐N‐glycopyranosides from glycals and amines with exclusive β‐stereoselectivity under room temperature conditions is reported. This method was achieved via palladium‐catalyzed Tsuji‐Trost amination followed by dihydroxylation directly, tolerating anilines, heterocyclic aromatic amines, and N,O‐dimethylhydroxylamine, especially the reaction of primary amines and glycals has not been reported before. Furthermore, the protocol was applied to modify clinical drugs (prazosin, imiquimod) and construct the analogue of the natural product amphimedoside A. [ABSTRACT FROM AUTHOR]

An efficient protocol for the C−N cross‐coupling of aryl chlorides with (hetero)aryl‐ and alkyl amines under nickel catalysis has been developed. The main advantage of the protocol is the use of a self‐activated Ni/NHC catalytic system generated in situ from readily available bench‐stable air‐tolerant precursors: NiCl2Py2, IPr ⋅ HCl, and sodium tert‐butoxide. A mass spectrometry mechanistic study of the reaction system revealed the dynamics of competitive processes of Ni/NHC active species formation and degradation involving NHC reductive elimination reactions and tert‐butoxide base. Optimization of the NiCl2Py2/IPr ⋅ HCl/tBuONa ratio and the reaction temperature allowed efficient catalysis to be achieved. The developed simple protocol represents an alternative for methods relying on the use of air‐sensitive and unstable Ni(cod)2 or expensive well‐defined Ni/NHC precatalysts. [ABSTRACT FROM AUTHOR]

A series of nickel(II) porphyrins bearing one or two bulky nitrogen donors at the meso positions were prepared by using Ullmann methodology or more classical Buchwald–Hartwig amination reactions to create the new C-N bonds. For several new compounds, single crystals were obtained, and the X-ray structures were solved. The electrochemical data of these compounds are reported. For a few representative examples, spectroelectrochemical measurements were used to clarify the electron exchange process. In addition, a detailed electron paramagnetic resonance (EPR) study was performed to estimate the extent of delocalization of the generated radical cations. In particular, electron nuclear double resonance spectroscopy (ENDOR) was used to determine the coupling constants. DFT calculations were conducted to corroborate the EPR spectroscopic data. [ABSTRACT FROM AUTHOR]

Herein, we developed a fluoride‐mediated nucleophilic aromatic amination of chloro‐1H‐1,2,3‐triazolium salts. Various functional groups were tolerated in this reaction, which enabled the synthesis of functionalized amino‐1H‐1,2,3‐triazolium salts. In addition, we investigated the catalytic properties of triazolium‐based N‐heterocyclic imines (NHIs) for cyanosilylation of ketones. The substituent was found to play a crucial role for inducing high catalytic activity. [ABSTRACT FROM AUTHOR]

Single-electron reduction of a carbonyl by photoredox catalysis enables the generation of ketyl radicals, providing a benign procedure for constructing C–C bonds. However, external photocatalysts are required. In this paper, photoinduced generation of ketyl radicals and application in C–C coupling are reported, which require no use of any external photocatalyst. Irradiation of carbonyl with purple light in the presence of a tertiary amine generates highly reactive ketyl radicals, enabling a series of important reactions in synthetic chemistry, such as the reductive coupling of aldehydes, ketones, and imines, the allylation of aldehydes, the Barbier reaction, reductive arylation, and aldehyde–aniline coupling. We also present evidence to support the ketyl radicals being formed via photoinduced intermolecular electron transfer from the tertiary amine to aryl aldehydes. [ABSTRACT FROM AUTHOR]

Reversing the conventional site‐selectivity of C−H activation provides efficient retrosynthetic disconnections to otherwise unreactive bonds. Described herein is the Brønsted acid‐catalyzed reaction that selectively performs meta‐amination of anisidines with aliphatic‐, heterocyclic‐ and aromatic amines in a one‐pot procedure. In addition to dramatically simplifying the synthesis of meta‐substituted anilines, our approach has the advantage of the scalability and remarkable functional group tolerance, including late‐stage functionalization of pharmaceutical compounds and natural products. The control experiments and detailed computational analysis provide insight into the reaction mechanism and the origin of meta‐selectivity. The protocol extended to the synthesis of challenging tri‐aminated arenes and successfully applied for the efficient synthesis of 5‐HT6 receptor antagonists, the anti‐psychotic drugs viz.. SB‐214111, SB‐258510, and specifically, anti‐schizophrenic drug SB‐271046. [ABSTRACT FROM AUTHOR]

A facile reductive amination procedure for electron-poor heterocyclic amines with aromatic and aliphatic aldehydes has been developed. The key to success was the use of triethylsilane (Et3 SiH) as reducing agent, in combination with trifluoroacetic acid (TFA) in refluxing CH2 Cl2. The reductive aminations are fast and clean, and allow for the isolation of the alkylated amines in high yields and purity after crystallization or chromatographic purification. The robustness and scalability of the process has been demonstrated for one substrate combination on 750 g scale, leading to the isolation of the corresponding product in 93% yield. [ABSTRACT FROM AUTHOR]

A new group of aromatic porphyrinoids was obtained by an oxidative insertion of primary amines into the antiaromatic ring of 5,14-dimesityl-norcorrolatonickel(II) activated by iodosobenzene. The substituted 10-azacorroles thus formed were characterized by spectroscopic and electrochemical methods, and XRD analysis. Protonated forms of azacorroles were shown to remain aromatic despite disconnection of the original π-electron delocalization path. [ABSTRACT FROM AUTHOR]

The construction of N-substituted amines from biomass-derived aryl ethers via reductive aminolysis is an emerging and highly attractive strategy for biomass valorization. However, realizing this transformation remains a great challenge over heterogeneous catalysts at a low H2 pressure. Herein, we designed Hf-exchanged montmorillonite supported Pd nanoparticles (Pd/Hf-MMT) as a functional heterogeneous catalyst. Very interestingly, the fabricated Pd/Hf-MMT was highly efficient for the direct reductive aminolysis of aryl ethers with amines to synthesize various N-cyclohexyl-substituted amines at a low H2 pressure of 0.3 MPa without using any homogeneous acidic additives. Systematic investigations revealed that the strong acidity of Hf-MMT and the lower electron density of metallic Pd synergistically resulted in the excellent activity of Pd/Hf-MMT. Notably, the Pd/Hf-MMT catalyst has great potential for practical applications because of some obvious advantages, such as low H2 pressure, the heterogeneous nature, high efficiency, and broad substrate scope. [ABSTRACT FROM AUTHOR]

The performance of a series of cobalt-based composites in catalytic amination of aromatic aldehydes by amines in the presence of hydrogen as well as hydrogenation of quinoline was studied. The composites were prepared by pyrolysis of CoII acetate, organic precursor (imidazole, 1,10-phenantroline, 1,2-diaminobenzene or melamine) deposited on aerosil (SiO2). These composites contained nanoparticles of metallic Co together with N-doped carboneous particles. Quantitative yields of the target amine in a reaction of p-methoxybenzaldehyde with n-butylamine were obtained at p(H2) = 150 bar, T = 150 °C for all composites. It was found that amination of p-methoxybenzaldehyde with n-butylamine and benzylamine at p(H2) = 100 bar, T = 100 °C led to the formation of the corresponding amines with the yields of 72–96%. In the case of diisopropylamine, amination did not occur, and p-methoxybenzyl alcohol was the sole or the major reaction product. Reaction of p-chlorobenzaldehyde with n-butylamine on the Co-containing composites at p(H2) = 100 bar, T = 100 °C resulted in the formation of N-butyl-N-p-chlorobenzylamine in 60–89% yields. Among the considered materials, the composite prepared by decomposition of CoII complex with 1,2-diaminobenzene on aerosil showed the highest yields of the target products and the best selectivity in all studied reactions. [ABSTRACT FROM AUTHOR]

Allylamines are important building blocks in the synthesis of bioactive compounds. The direct coupling of allylic C−H bonds and commonly available amines is a major synthetic challenge. An allylic C−H amination of 1,4‐dienes has been accomplished by palladium catalysis. With aromatic amines, branch‐selective allylic aminations are favored to generate thermodynamically unstable Z‐allylamines. In addition, more basic aliphatic cyclic amines can also engage in the reaction, but linear dienyl allylic amines are the major products. [ABSTRACT FROM AUTHOR]

A protocol for parallel C(sp3)−C(sp3) coupling of (hetero)aromatic aldehydes and (hetero)arylmethyl amines based on a reductive amination – "nitrogen deletion" reaction sequence has been developed. After preliminary validation experiments, an illustrative compound library of 25 members was prepared with 76 % synthetic efficiency. The estimated chemical space accessible by the proposed approach covers almost 600 000 representatives that are scarcely represented in current compound databases. [ABSTRACT FROM AUTHOR]

A ruthenium(II)‐catalyzed hydroamination of allenoates with arylamines has been developed. This strategy provides an approach to synthesize E‐allylic amines in good yields with high atom‐economy and high levels of chemo‐, regio‐ and E‐selectivities with a broad substrate scope. [ABSTRACT FROM AUTHOR]

Herein, we report a new, simple, one pot and chemoselective method for N‐methylation and N,N‐dimethylation of aliphatic and aromatic amines under ambient conditions using NHC‐borane i.e 1,3‐dimethylimidazole‐2‐ylidene borane (diMe‐Imd‐BH3), as reducing agent. The present strategy has significant advantages like mild reaction conditions, quick and effortless work‐up processes, and the use of non‐toxic inexpensive reagents. The amines with acid‐sensitive moieties are also methylated successfully. [ABSTRACT FROM AUTHOR]

Herein, we report a new, simple, one pot and chemoselective method for N‐methylation and N,N‐dimethylation of aliphatic and aromatic amines under ambient conditions using NHC‐borane i.e 1,3‐dimethylimidazole‐2‐ylidene borane (diMe‐Imd‐BH3), as reducing agent. The present strategy has significant advantages like mild reaction conditions, quick and effortless work‐up processes, and the use of non‐toxic inexpensive reagents. The amines with acid‐sensitive moieties are also methylated successfully. [ABSTRACT FROM AUTHOR]

The catalytic properties of a nickel phosphide catalyst supported on silica gel in the reductive amination of carbonyl compounds were studied in a flow reactor using molecular hydrogen as a reducing agent. The reaction was carried out in toluene with a slight excess of amine at a total pressure of 10 bar and a temperature of 140–170°C. With the use of primary aliphatic amines, the 6.3% Ni2P/SiO2 catalyst provided the formation of secondary amines with a yield to 99%. The yield of the target product depended on the carbonyl compound and decreased in the following order: aliphatic aldehydes > aliphatic ketones ~ aromatic aldehydes > aromatic ketones. This was explained by a decrease in the electrophilic properties in this sequence. At the same time, the yield of secondary amines in reactions involving aromatic amines, which are weaker nucleophiles, was much lower. [ABSTRACT FROM AUTHOR]

An account of our development of reactions to construct N -heterocycles by triggering cyclization–migration tandem reactions from aryl azides, nitroarenes, and aryl amines is described. The reactivity patterns of metal N -aryl nitrenes, nitrosoarenes, N -aryl nitrogen radical anions, and N -aryl nitrenoids are compared. 1 Introduction 2 Unlocking the Reactivity Embedded in Aryl Azides 3 Exploiting the Reactivity of Nitrosoarenes Generated from Nitroarenes 4 Radical Anion N -Aryl Nitrogen Reactive Intermediates from Nitroarenes 5 Oxidation of Aryl Amines to Access Electrophilic N -Aryl Nitrenoids 6 Conclusion [ABSTRACT FROM AUTHOR]

An electrosynthetic approach was developed for the oxidative C–H/N–H cross-coupling amination of cyclic sulfamidate imines under undivided electrolytic conditions via an atom- and step-economic method. In this transformation, a wide variety of cyclic or acyclic dialkyl amines, amino acid derivatives, and more challenging primary anilines acted as suitable substrates with good reaction outcomes. The synthetic advantage of this electrochemical method is augmented by high functional group compatibility (86 examples), ease of scale-up to gram scale, and accomplishment of late-stage functionalization of complex biologically relevant molecules, which provides an efficient tool with broad potential application prospects in medicinal and synthesis chemistry. Mechanistic studies reveal that this transformation probably occurred through a radical process. [ABSTRACT FROM AUTHOR]

The immobilization of ciprofloxacin on chloromethyl polystyrene resin can be used as an efficient recyclable ligand for promoting a copper-catalyzed coupling reaction of (hetero)aryl halides and amines, and provides excellent results. The ligand is easily recovered and reused without significantly reducing its catalytic ability. It is environmentally friendly, and no ciprofloxacin was detected in the reaction solution. Thus, many important structural units for the pharmaceutical and chemical industries can be assembled utilizing this method. [ABSTRACT FROM AUTHOR]

A transition‐metal‐free aminocyanation of aryl alkynes has been achieved using indium tribromide, InBr3 or B(C6F5)3 as a Lewis acid. This aminocyanation protocol features with non‐toxic cyanide source, a good substrate scope and potentially valuable aminocyanation products. Mechanistic studies reveal the complex formation between Lewis acid and alkyne to produce in situ alkyne nitrile as a key intermediate. Further hydroamination of alkyne nitrile with arylamines affords the E‐selective (E:Z=70:30 to 90:10) β‐aminoacrylonitrile derivatives. [ABSTRACT FROM AUTHOR]

The functionalization of surfaces using chitosan oligomers is of great interest for a wide range of applications in biomaterial and biomedical fields, as chitosan oligomers can provide various functional properties including biocompatibility, wetting, adhesion, and antibacterial activity. In this study, an innovative process for the regiospecific chemical grafting of reducing-end-modified chitosan oligomers brushes onto silicon wafers is described. Chitosan oligomers (COS) with well-defined structural parameters (average DP ~19 and DA ~0%) and bearing a 2,5-anhydro-d-mannofuranose (amf) unit at the reducing end were obtained via nitrous acid depolymerization of chitosan. After a silanization step where silicon wafers were modified with aromatic amine derivatives, grafting conditions were studied to optimize the reductive amination between aldehydes of amf-terminated COS and aromatic amines of silicon wafers. Functionalized surfaces were fully characterized by AFM, ATR-FTIR, ellipsometry, contact angle measurement, and ToF-SIMS techniques. Smooth surfaces were obtained with a COS layer about 3 nm thick and contact angle values between 72° and 76°. Furthermore, it was shown that the addition of the reducing agent NaBH3CN could positively improve the COS grafting density and/or led to a better stability of the covalent grafting to hydrolysis. Finally, this study also showed that this grafting process is also efficient for chitosan oligomers of higher DA (i.e., ~21%). [ABSTRACT FROM AUTHOR]

A concise sequential protocol is developed to synthesize 3C-alkylated active methylene substituted 2H-indazole derivatives via a nucleophilic ring opening reaction (NRO) of o-nitro donor–acceptor cyclopropanes (DACs) with primary arylamines catalyzed by Ni(ClO4)2·6H2O followed by a SnCl2·2H2O-mediated intramolecular reductive cyclisation. The di-ester functionality can be transformed into the corresponding monoesters, acids, alcohols and amides that form the core units of important biologically active molecules. [ABSTRACT FROM AUTHOR]

Nitrogen fixation is industrially realized by mass production of ammonia, the principal intermediate nitrogen source for N‐containing organic molecules. Instead, direct C−N bond formation from dinitrogen (N2) is of great interest but remains a challenge. Here, by virtue of unique plasma–liquid interactions, we developed an environmentally benign one‐pot approach to directly couple benzene and N2, two naturally abundant yet chemically inert molecules, into value‐added arylamines. Under the optimal conditions, an amination yield of 45 % was rapidly achieved, far better than the reported benzene amination efficiency using ammonia. A tentative reaction mechanism was proposed involving the long‐lived N2 (A3Σu+) and N2+ species, as evidenced by the key intermediates detected. With a deeper mechanistic understanding and by further optimizing the plasma reactor, the realization of cost‐effective electrical amination of benzene with N2 could become reality. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru@Beta was directly synthesized to confine Ru NPs within Beta zeolites. • Ru@Beta was highly active in the N-alkylation of amines with aromatic alcohols. • High yield/TON/TOF, stable recyclability, and broad substrate scope were obtained. • Synergy of confined Ru NPs and acid sites contributed to the high performance. • Moderate Ru − H intensity on the confined metal sites accelerated H-transfer process. Direct hydrogen transfer amination of alcohols with amines is an environmentally friendly and atom-economical route for the synthesis of N-alkylamines. Noble metal species are highly catalytic active sites, but the exorbitant price makes the urgency to boost the atom efficiency with stable recyclability. Herein, we demonstrated that encapsulation of Ru nanoparticles (NPs) within BEA zeolite through direct hydrothermal approach greatly promoted the catalytic efficiency in the N-alkylation of aromatic alcohols and amines under additive- and solvent-free conditions, resulting in the high yield (∼93 %), maximum turnover number (TON) of 12,822 and turnover frequency (TOF) of 9012 h−1, with stable recyclability and extendable substrate scope. The kinetic studies and in-situ characterizations revealed that the synergy of confined Ru NPs and adjacent acid sites of BEA zeolite significantly promoted the C–H bond activation in the rate-determining step of alcohol dehydrogenation into aldehydes. Besides, the acid sites also accelerated the condensation of aldehyde intermediates and anilines to promote the kinetic equilibrium, while the moderate strength of the Ru–H bond resulting from the confined Ru NPs is advantageous to balance the dehydrogenation and hydrogenation steps to reach the fascinating H-transfer process. [ABSTRACT FROM AUTHOR]

• RONCs transformation and ammonification is the key step for total nitrogen removal. • The cleavage of C-N bond limited the transformation of electrophilic RONCs to NH 4 +. • Electrostimulation enhances the anaerobic reduction of RONCs into aromatic amines. • Micro-aeration enhances the aerobic oxidation of amine products into NH 4 +. • Regulating microbial redox reactions facilitates the transformation of RONCs. Biotechnology for wastewater treatment is mainstream and effective depending upon microbial redox reactions to eliminate diverse contaminants and ensure aquatic ecological health. However, refractory organic nitrogen compounds (RONCs, e.g., nitro-, azo-, amide-, and N-heterocyclic compounds) with complex structures and high toxicity inhibit microbial metabolic activity and limit the transformation of organic nitrogen to inorganic nitrogen. This will eventually result in non-compliance with nitrogen discharge standards. Numerous efforts suggested that applying exogenous electron donors or acceptors, such as solid electrodes (electrostimulation) and limited oxygen (micro-aeration), could potentially regulate microbial redox reactions and catabolic pathways, and facilitate the biotransformation of RONCs. This review provides comprehensive insights into the microbial regulation mechanisms and applications of electrostimulation and micro-aeration strategies to accelerate the biotransformation of RONCs to organic amine (amination) and inorganic ammonia (ammonification), respectively. Furthermore, a promising approach involving in-situ hybrid anaerobic biological units, coupled with electrostimulation and micro-aeration, is proposed towards engineering applications. Finally, employing cutting-edge methods including multi-omics analysis, data science driven machine learning, technology-economic analysis, and life-cycle assessment would contribute to optimizing the process design and engineering implementation. This review offers a fundamental understanding and inspiration for novel research in the enhanced biotechnology towards RONCs elimination. [Display omitted] [ABSTRACT FROM AUTHOR]

The direct asymmetric reductive amination of heteroaryl ketones has been a long‐standing synthetic challenge. Here we report the engineering of an amine dehydrogenase (AmDH) from Jeotgalicoccus aerolatus for the asymmetric synthesis of chiral α‐(hetero)aryl primary amines in excellent conversions (up to 99 %) and enantioselectivities (up to 99 % ee). The best AmDH variant (Ja‐AmDH‐M33) exhibited high activity and specificity toward alkyl (hetero)aryl ketones, even for those bearing a bulky alkyl chain. An efficient directed evolution approach based on molecular docking was implemented to enlarge the active pocket with a more hydrophobic entrance, which is responsible for the high activity. The Ja‐AmDH‐M33 was also used for preparative‐scale synthesis of pharmaceutically relevant amines and a key intermediate of chiral pincer ligands, which highlighted its practical application in synthetic chemistry. [ABSTRACT FROM AUTHOR]

We describe the oxygenation of tertiary arylamines, and the amination of tertiary arylamines and phenols. The key step of these coupling reactions is an iron‐catalyzed oxidative C−O or C−N bond formation which generally provides the corresponding products in high yields and with excellent regioselectivity. The transformations are accomplished using hexadecafluorophthalocyanine−iron(II) (FePcF16) as catalyst in the presence of an acid or a base additive and require only ambient air as sole oxidant. [ABSTRACT FROM AUTHOR]

A protocol for the synthesis of unsymmetrical ureas substituted by pyridyl/quinolinyl moiety has been developed. This method concluded in metal‐ and base‐free reamination of N,N‐dimethyl‐N'‐hetaryl ureas with a wide range of aryl and alkyl amines. The isolated yields vary from 40 to 96% depending on the nucleophilicity of the amines. The scope of this method includes more than 50 examples. The reaction is not hindered by either donor or acceptor groups as well as diverse functionalities. The synthesis can be easily scaled to gram quantities. Theoretical calculations supported by experimental data allowed us to propose a plausible mechanism for the process. This reaction takes place through the intermediate formation of hetaryl isocyanate. [ABSTRACT FROM AUTHOR]

NADH-dependent phenylalanine amine dehydrogenase (F-AmDH) engineered from phenylalanine dehydrogenase (PheDH) catalyzes the synthesis of aromatic chiral amines from prochiral ketone substrates. However, its low coenzyme affinity and catalytic efficiency limit its industrial application. Here, we developed a chimeric amine dehydrogenase, cFLF-AmDH, based on the relative independence of the structure at the domain level, combined with a substrate-binding domain from F-AmDH and a high-affinity cofactor-binding domain from leucine amine dehydrogenase (L-AmDH). The kinetic parameters indicated that cFLF-AmDH showed a twofold improvement in affinity for NADH and a 4.4-fold increase in catalytic efficiency (kcat/Km) compared with the parent F-AmDH. Meanwhile, cFLF-AmDH also showed higher thermal stability, with the half-life increased by 60% at 55 °C and a broader substrate spectrum, than the parent F-AmDH. Molecular dynamics simulations suggested that the constructed cFLF-AmDH had a more stable structure than the parent F-AmDH, thereby improving the affinity of the coenzyme. The reaction rate increased by 150% in the reductive amination reaction catalyzed by cFLF-AmDH. When the NAD+ concentration was 0.05 mM, the conversion rate was increased by 150%. These results suggest that the chimeric protein by domain shuffling from different domain donors not only increased the cofactor affinity and catalytic efficiency, but also changed the specificity and thermal stability. Our study highlights that domain engineering is another effective method for creating biodiversity with different catalytic properties. [ABSTRACT FROM AUTHOR]

An efficient access to the novel 5-(het)arylamino-1,2,3-triazole derivatives has been developed. The method is based on Buchwald–Hartwig cross-coupling reaction of 5-Amino or 5-Halo-1,2,3-triazoles with (het)aryl halides and amines, respectively. As result, it was found that palladium complex [(THP-Dipp)Pd(cinn)Cl] bearing expanded-ring N-heterocyclic carbene ligand is the most active catalyst for the process to afford the target molecules in high yields. [ABSTRACT FROM AUTHOR]

The mini-review systematizes recently published data on nucleophilic N- and C-amination of electron-deficient tropylium salts with aromatic amines. [ABSTRACT FROM AUTHOR]

The reductive amination of aromatic aldehydes and aromatic amines, performed in the Brønsted acidic ionic liquid [Et3NH][HSO4], using sodium borohydride as a reducing agent is reported. In this protocol, the ionic liquid plays a crucial role in efficiently converting aromatic aldehydes to amines in excellent yields, without the formation of side products. In the presence of [Et3NH][HSO4], the imine was generated in situ from the reaction between the aromatic aldehydes and aromatic amines, and underwent smooth reduction with sodium borohydride. This one‐pot synthesis is practically simple and sustainable. The catalyst [Et3NH][HSO4] also has a demonstrably wide applicability, in that it can be used with a variety of aromatic aldehydes and aromatic amines substituted by various electron‐withdrawing and electron‐donating groups. The role of IL [Et3NH][HSO4] in catalytic reductive amination is validated with the help of density functional theory (DFT)‐based computational studies. [ABSTRACT FROM AUTHOR]