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The catalytic activity of a Ru complex 1, bearing a fused π‐conjugated imidazo[1,2–a][1,8]naphthyridine‐based mesoionic carbene (MIC) ligand, is examined for the oxidation of primary amines. Complex 1 affords nitrile or imine depending on the nature of the terminal oxidants and solvents used in the reactions. Primary amines are converted to nitriles using NaIO4 in EtOAc/H2O mixture, whereas imines are obtained under O2 balloon pressure in toluene. A variety of nitriles and imines are accessed with high yields and selectivity. A set of control experiments, reaction profiles, and kinetic studies are undertaken to disclose the mechanistic details for nitrile and imine formation. The catalytic reactions illustrate a subtle dependency on the choice of oxidants and solvents in the oxidation of primary amines. [ABSTRACT FROM AUTHOR]

A catalyst- and additive-free synthesis of 2-benzyl N-substituted anilines from (E)-2-arylidene-3-cyclohexenones and primary amines has been reported. The reaction proceeds smoothly through a sequential imine condensation–isoaromatization pathway, affording a series of synthetically useful aniline derivatives in acceptable to high yields. Mild reaction conditions, no requirement of metal catalysts, operational simplicity and the potential for scale-up production are some of the highlighted advantages of this transformation.

In this work, partial reductive amination of 5‐hydroxymethylfurfural (HMF) with gaseous ammonia over iridium supported on γ‐Al2O3, TiO2, SiO2 and carbon has been studied. The influence of the support and pressure was investigated in the valorization under mild conditions of HMF to 5‐(aminomethyl)‐2‐furanmethanol (AMFM). The catalysts were characterized by TEM, SEM‐EDS, N2 sorption Isotherms, TGA, CO‐Chemisorption, TPR, XRD, NH3‐TPD, ICP‐AES and XPS. The maximum activity and high rates were obtained for all catalytic systems. At 50 minutes of the reaction the Ir/C catalyst achieved 93 % of conversion and exhibited the highest yield and selectivity of 92 % and 99 % respectively, to the desired product 5‐(aminomethyl)‐2‐furanmethanol. The main properties that influence activity and selectivity are related to the amount of iridium on the surface and catalyst acidity. After the third cycle, 63 % and 59 % of selectivity and yield to AMFM respectively at 93 % of conversion were obtained. [ABSTRACT FROM AUTHOR]

9-(Pyridin-2-yl)-7-[2-(pyridin-2-yl)ethyl]-7H-acenaphtho[1,2-b]pyrrole (1) was formed by a reaction of 2-(2-aminoethyl)pyridine and acenaphthenequinone in the presence of ZnCl2. At the first step salt 1-Zn was isolated, which consists of the doubly protonated form of 9-(pyridin-2-yl)-7-(2-(pyridin-2-yl)ethyl)-7H-acenaphtho[1,2-b]pyrrole as the cation and ZnCl42– as the counterion. Salt 1-Zn was further treated by K2C2O4 to give unexpected compound 1. The redox properties of 1 were investigated by voltammetry. It was found that the measured potential values for reduction and oxidation peaks are correspond to acenaphthene-based ligands. Compound 1 is oxidized upon storage in air to give the corresponding 6b-hydroxy-9-(pyridin-2-yl)-7-(2-(pyridin-2-yl)ethyl)-6bH-acenaphtho[1,2-b]pyrrol-8(7H)-one (2). All newly obtained compounds were isolated and characterized by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

9-(Pyridin-2-yl)-7-[2-(pyridin-2-yl)ethyl]-7H-acenaphtho[1,2-b]pyrrole (1) was formed by a reaction of 2-(2-aminoethyl)pyridine and acenaphthenequinone in the presence of ZnCl2. At the first step salt 1-Zn was isolated, which consists of the doubly protonated form of 9-(pyridin-2-yl)-7-(2-(pyridin-2-yl)ethyl)-7H-acenaphtho[1,2-b]pyrrole as the cation and ZnCl42– as the counterion. Salt 1-Zn was further treated by K2C2O4 to give unexpected compound 1. The redox properties of 1 were investigated by voltammetry. It was found that the measured potential values for reduction and oxidation peaks are correspond to acenaphthene-based ligands. Compound 1 is oxidized upon storage in air to give the corresponding 6b-hydroxy-9-(pyridin-2-yl)-7-(2-(pyridin-2-yl)ethyl)-6bH-acenaphtho[1,2-b]pyrrol-8(7H)-one (2). All newly obtained compounds were isolated and characterized by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Ru(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in chloride solutions, that is, formation of RuCl6-n(H2O)n(3-n)- (n=0-6). Therefore, it is difficult to extract Ru(III) by solvent extraction, and Ru(III) is currently separated and purified by the oxidative distillation method. If Ru can be separated and recovered from chloride solutions by solvent extraction, an efficient separation and recovery process for PGMs can be established. Therefore, it is important to investigate the solvent extraction of Ru(III) from chloride solutions. The authors have previously studied solvent extraction of Ru(III) with 2-ethylhexylamine (EHA), which is a primary amine extractant, from chloride solutions and shown that the extraction of Ru(III) with EHA from chloride solutions without the addition of Sn (II)was high. However, the stripping of Ru(III) was difficult. In the present study, extractions of Ru from hydrochloric acid solutions with EHA and octylamine (OA), which are primary amines, were tested to clarify the extraction of Ru and the stripping of Ru with various stripping solutions. The extraction efficiency of Ru with EHA and OA from hydrochloric acid solutions without the addition of Sn (II) was high. And also, it was found that Ru could be easily stripped from EHA with sodium sulfate solutions.

Cephalexin and Cefaclor, are widely prescribed antibiotics known for their characteristic bitter taste. This bitterness is attributed to the specific chemical composition of these substances. The sensory experience of bitterness is influenced by distinct functional groups present in various foods and chemicals. Researchers have developed diverse techniques and strategies to modify these antibiotics' chemical structure while preserving their therapeutic efficacy to overcome this taste challenge. This study examines the role of the primary amine functional group in generating the bitter taste associated with Cephalexin andCefaclor. Methods: Schiff base reaction used to make Imines of Cephalexin and Cefaclor on their Primary amine functional group by reacting with Aldehydes (Citral, Vanillin, and Benzaldehyde). The Schiff bases bitternesselation evaluated through gustatory volunteers. Results: Formation of imines on the primary amine functional group in both Cephalexin and Cefaclor was achieved through the creation of Schiff bases with aldehydes, specifically Citral, Vanillin, and b enzaldehyde. This chemical transformation led to a slight alteration in the bitterness intensity measurement. Conclusions: The bitterness of Cephalexin and Cefaclor could be attributed to their Primary amine to a considerable extent, but not solely to the primary amine. Since the bitterness would not be obliterated evenafter manipulating it. The bitterness of the Cephalosporins is multifactorial involving other functional groupshappen to be found in their chemical structure. Further investigations should be carried out for each functional group of Cephalexin and Cefaclor evaluating the contribution of each of the

The synthesis of primary amines via the reductive amination of alcohols involves a hydrogen-borrowing or hydrogen-transfer mechanism, which consists of three main steps: alcohol hydroxyl dehydrogenation, carbonyl imidization, and imine hydrogenation. Heterogeneous catalysts are widely used for this reaction because of their high performance and amenability to separation and reuse. However, the efficiency of reductive amination is limited by the dehydrogenation step, which is severely affected by the competitive adsorption of NH3. We hope to improve the efficiency of reductive amination by increasing dehydrogenation efficiency. Therefore, in this overview, we introduce the research progress of alcohol reductive amination reaction catalyzed by heterogeneous metal catalysts, focusing on methods of enhancing dehydrogenation efficiency by screening the metal component and the acidity/alkalinity of the support. Finally, we propose some new strategies for the preparation of catalysts from the perspective of overcoming the competitive adsorption of NH3 and speculate on the design and synthesis of novel catalysts with high performance in the future. [ABSTRACT FROM AUTHOR]

We report herein a straightforward transfer of a free amino group (NH2) from a commercially available nitrogen source to unfunctionalized, native carbonyls (amides and ketones) resulting in direct α‐amination. Primary α‐amino carbonyls are readily produced under mild conditions, further enabling diverse in situ functionalization reactions—including peptide coupling and Pictet–Spengler cyclization—that capitalize on the presence of the unprotected primary amine. [ABSTRACT FROM AUTHOR]

Abstract Pregabalin, a GABA analogue is used to treat epilepsy and neuropathic pain. The drug poses problems in analytical quantification when estimated at a shorter UV wavelength. The expensive and non-repetitive reported analytical methods necessitate the utility and development of an accurate, precise, repetitive, simple and highly sensitive colorimetric method for pregabalin in solution as well as sustained release mini matrices. Pregabalin (having primary amino group) was derivatized at alkaline pH of mixture with optimized ninhydrin solution at ambient temperature (25oC). The ninhydrin-pregabalin derivatized complex (Ruhemann’s Purple) was analyzed for drug concentration at absorption maximum (λmax) of 570nm. The linearity was observed in the concentration range of 5-150 µg/mL with coefficient of correlation, 0.998. The developed analytical method was validated according to ICH guidelines and proved to be highly sensitive (LOD 0.917µg/mL, LOQ 3.055µg/mL), with good inter-day as well as intra-day accuracy and precision as 4.65% and 3.75%, respectively. The proposed method was proved to be a simple, sensitive, precise and accurate for the estimation of the minute concentrations of pregabalin in pure form and the developed formulations. Results verified that the proposed method could determine pregabalin at the ambient temperature without requiring high temperatures used in the existing methods. It was concluded that developed method was easier and more suitable for analysis of pregabalin in quality control of commercial preparations.

Cobalt (Co) as a substitute of noble-metal catalysts shows high catalytic capability for production of the widely used primary amines through the reductive amination. However, the synthesis of Co catalysts usually involves the introduction of organic compounds and the high-temperature pyrolysis, which is complicated and difficult for large-scale applications. Herein, we demonstrated a facile and efficient strategy for the preparation of Co catalysts through the in situ reconstruction of cobalt borate (CoBOx) during the reductive amination, delivering a high catalytic activity for production of benzylamine from benzaldehyde and ammonia. Initially, CoBOx was transformed into Co(OH)2 through the interaction with ammonia and subsequently reduced to Co nanoparticles by H2 under the reaction environments. The in situ generated Co catalysts exhibited a satisfactory activity and selectivity to the target product, which overmatched the commonly used Co/C, Pt or Raney Ni catalysts. We anticipate that such an in situ reconstruction of CoBOx by reactants during the reaction could provide a new approach for the design and optimization of catalysts to produce primary amines.

Beta-zeolite supported ruthenium catalysts for reductive amination of 5-hydroxymethyl-2-furaldehyde (HMF) with an aqueous solution of ammonia (NH3 aq.) and molecular hydrogen (H2) are examined to synthesize the corresponding primary amine of 5-aminomethyl-2-furylmethanol (FAA). Various SiO2/Al2O3 (Si/2Al) ratios of the beta-zeolite support were used to prepare the Ru-based catalysts. It was observed that the Si/2Al ratio was contributed to the catalytic activity, and the Si/2Al = 150 of beta-zeolite was found to be the most active for Ru catalyzed reductive amination of HMF, affording ca. 70% yield. Characterization techniques were taken to analysis the factors that influence the reactivity of catalysts, and which revealed that not only the ruthenium nanoparticle size but also the ratio of RuO2 against metallic Ru species were crucial factors for the reactivity of reductive amination of HMF to FAA. [ABSTRACT FROM AUTHOR]

Open‐air plasma jets are becoming increasingly popular due to easy and affordable large‐scale coating deposition on diverse substrates. However, direct deposition of primary amine groups (NH2), which are attractive as covalent anchor points for molecule grafting, remains challenging. In this study, 3‐aminopropyltrimethoxysilane (APTMS) has been directly polymerized on glass by a plasma jet. Quantification of NH2 showed that APTMS polymerization and NH2 degradation were correlated with Yasuda's parameter and that a compromise between NH2 retention and coating stability is required. Evaporation of APTMS was found to improve surface smoothness and homogeneity but was found to decrease the deposited NH2 concentration, from 3.7 ± 1.3 NH2/nm2 to three times lower. Results showed that deposited NH2 could be used as anchor points for polyethylene glycol chain immobilization. [ABSTRACT FROM AUTHOR]

Aqueous asymmetric catalysis using chiral covalent organic frameworks (COFs) represents a significant advancement but remains to be explored. Herein, we present the first example of aqueous asymmetric catalysis catalyzed by a primary amine-tagged chiral D -ADP-TAPB COF. The D -ADP-TAPB COF was synthesized by the postsynthetic deprotection of D -ADP-TAPB-Boc bearing a protective tert-butoxycarbonyl (Boc) group, which was constructed by a Schiff-base reaction between an alanine-derived chiral building block ( D -ADP-Boc) and 1,3,5-tris(4-aminophenyl)benzene (TAPB). The crystalline D -ADP-TAPB COF exhibits a uniform, spherical morphology with abundant, well-distributed chiral primary amines, rendering it highly active in the asymmetric aldol reaction between cyclohexanone and 4-nitrobenzaldehyde. Notably, this reaction is conducted entirely in water, achieving impressive yields and enantiomeric excess (ee) values of up to 90 and 85%, respectively. To the best of our knowledge, D -ADP-TAPB COF represents the first chiral COF catalyst with high reactivity and enantioselectivity for an asymmetric aldol reaction solely in water, eliminating the need for conventional organic solvents. Moreover, a plausible mechanism for D -ADP-TAPB COF-mediated aqueous asymmetric aldol reactions is elucidated. This work not only expands the toolbox for designing rare primary amine-functionalized chiral COFs for asymmetric catalysis but also opens exciting avenues for developing green and water-based enantioselective catalysis.

Amines play an important role in synthesizing drugs, pesticides, dyes, etc. Herein, we report on an efficient catalyst for the general construction of amine mediated by nickel boride nanoclusters supported by a TS-1 molecular sieve. Efficient production of amines was achieved via catalytic hydrogenation of N=X (X = C, O, H) bonds. In addition, the catalyst maintains excellent performance upon recycling. Compared with the previous reports, the high activity, simple preparation and reusability of the Ni-B catalyst in this work make it promising for industrial application in the production of amines. [ABSTRACT FROM AUTHOR]

Amine detection is of great importance as excess volatile amine exposure and increased concentration of biogenic amines in human body can cause adverse effects to human health. Thus, the development of easy-accessible and efficient fluorescent probes for amine detection is of great importance. In this study, we are the first to establish a cascade reaction sequence featuring imine formation followed by 6- endo - dig cyclization reaction for the development of sensitive and selective "turn-on" fluorescent probes toward primary amines by using the ortho -ethynylbenzaldehydes (EBAs) as the reaction site. The corresponding isoquinolinium products generated give a significant red-shifted absorbance change and highly intense "turn-on" fluorescence. Nine EBAs (EBA-1a-1e , EBA-2–5) were designed and synthesized to study the structure-photophysical property relationship (SPPR) for selective primary amine sensing. Our EBAs possessed a highly sensitive response toward primary amines in aqueous conditions within 30 min (LOD as low as 0.45 µM) with tunable absorption (338–430 nm) and emission (410–535 nm), large Stokes shift (up to 115 nm), and high fluorescence quantum yield (up to 0.86). EBA -loaded paper strips were prepared as a portable low cost tool for amine detection in solution, vapor, and food. Fluorogenic protein labelling and in-gel fluorescent imaging were efficiently achieved by using EBAs in which the fluorescence signal was obviously observed by naked eyes under 365 nm UV lamp. Moreover, the favorable membrane permeabilization, low to moderate cytotoxicity, and "turn-on" fluorescent response of EBA-1a-1e and EBA-4–5 allow wash-free live cell imaging. Interestingly, EBA-1a-1e and EBA-4 showed high selectivity to fluorescent imaging of mitochondria. [Display omitted] • Nine EBA probes detected primary amines via imine formation followed by 6- endo - dig cyclization. • The high selectivity toward primary amines was due to the formation of isoquinolinium products. • EBA -loaded paper strips detected primary amines in solution and vapor formats as well as food. • EBA acted as fluorogenic protein labelling reagents in solution and SDS-PAGE gel observed by 365 nm UV lamp. • EBA imaged mitochondria in live cell without installing mitochondrial targeting groups. [ABSTRACT FROM AUTHOR]

• The catalyst shows excellent catalytic activity for oxidation of primary amines. • Mechanistic studies revealed the generation of nitrile as an intermediate. • The catalyst is very stable and can be used repeatedly without loss of activity. • No palladium leached from PdNPore during the oxidation reaction. An efficient and highly selective heterogeneous catalyst system for aerobic oxidation of primary amines was developed using unsupported palladium nanopores (PdNPore). A variety of aromatic, aliphatic, and heterocyclic primary amines were oxidized to the corresponding amides in satisfactory to excellent yields using ambient air as an oxidant. No palladium was leached from PdNPore during the oxidation reaction. The catalyst could be readily recovered and reused without a decrease in catalytic activity. The kinetic studies and control experiments demonstrated that nitrile acts as an intermediate, which undergo hydration to afford amide as the final product. The nanoporous palladium was a highly efficient heterogeneous catalyst for oxidation of primary amines using air as an oxidant. A variety of primary amides were oxidized to the corresponding amides in high yields with excellent selectivities. The catalyst is easily recovered and reused without leaching and loss of activity. [Display omitted] [ABSTRACT FROM AUTHOR]

Chiral p -phenylene-based dicarboxamides featuring carboxamide and 2-arylacrylamide motifs were synthesised through a synthetic sequence involving conventional organic reactions followed by palladium-catalysed aminocarbonylation. 4-Iodoacetophenone was used as starting material to prepare to 1',4-diiodostyrene, which underwent several aminocarbonylation reactions, using in situ formed palladium-phosphine catalysts and various biologically relevant amines as N -nucleophiles such as, amino acid esters, nortropine, and aminoandrostane derivatives. By exploring the remarkable difference in reactivity between the iodoalkene and iodoarene functionalities, the aminocarbonylation of the iodoalkene moiety was carried first with high chemoselectivity, followed by sequential transformation of the iodoarene functionality into the corresponding carboxamide using a different nucleophile. This approach allowed us to obtain a range of otherwise challenging chiral dicarboxamides, in moderate to high isolated yields through highly chemoselective reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to apply the C-H activation strategy to the synthesis of novel organic catalysts, a novel primary amine-thiourea catalyst is designed and synthesized by using the developed inert C(sp3)-H amination method as a key step. First, using phenylalanine as the substrate and di-tert-butyl-azodicarboxylic acid as the nitrogen source, the corresponding amination products are obtained by employing the Pd-catalyzed inert C(sp3)-H amination method. Next, the chiral skeleton of 1,2-diamine privileged in organocatalysts is obtained by simple conversion. Then, a novel chiral primary amine-thiourea bifunctional organic catalyst is synthesized, whose structure is characterized by nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS). The synthesized catalyst is also successfully applied to the asymmetric Michael addition reaction of isobutyraldehyde with nitroolefins. Due to the advantages of transition metal-catalyzed C-H activation, such as simplicity, high efficiency, high atomic economy, and non pre-functionalization, its application to the development of small molecular catalysts will undoubtedly make the structure of catalyst more diversified and the synthesis process more efficient.

Amines are an important class of compounds in natural products and medicines. The universal availability of amides provides a potential way for the synthesis of amines. Herein, Ru/Nb2O5 catalyst is demonstrated to be highly efficient and stable for the selective hydrogenation of propionamide to propylamine (as a model reaction), with up to 91.4% yield of propylamine under relatively mild conditions. Results from XPS analyses, CO chemisorption, TEM images and DRIFTS spectra revealed that the unique properties of Nb2O5 can effectively activate the C=O group of amides, and the smaller Ru particles on Nb2O5 could further promote the activation, leading to superior catalytic performance of Ru/Nb2O5 for amide hydrogenation. Meanwhile, reducing the surface acidity of Nb2O5 can greatly inhibit the side reactions to by‐products, and further enhance the selectivity to amine. Moreover, this catalytic system is also applicable for the hydrogenation of a variety of amides and provides high potential for the industrial production of primary amines from amides. [ABSTRACT FROM AUTHOR]

Amino-functionalized six-membered cyclic carbonate tert-butyl(2-oxo-1,3-dioxan-5-yl) carbamate (TBC) was synthesized with tert-Butyloxycarbonyl (Boc) as protected group. Due to its thermal properties, ring-opening polymerization (ROP) carried out in a relatively low temperature, and Sn (Oct)2 as catalyst. A series of copolymers were prepared with L-lactide (LA), ε-Caprolactone (CL) as co-monomers, searching for proper components and ratios. The protecting Boc-group was easy to remove by using trifluoroacetic acid (TFA). The structures of TBC and copolymers were confirmed by 1H NMR and 13C NMR analysis. Copolymers were characterized by DSC, GPC and water contact angle analysis. The introduction of pendant amino groups resulted in a significant enhancement of hydrophilicity of the copolymers. [ABSTRACT FROM AUTHOR]

A catalyst- and additive-free synthesis of 2-benzyl N -substituted anilines from ( E )-2-arylidene-3-cyclohexenones and primary amines has been reported. The reaction proceeds smoothly through a sequential imine condensation-isoaromatization pathway, affording a series of synthetically useful aniline derivatives in acceptable to high yields. Mild reaction conditions, no requirement of metal catalysts, operational simplicity and the potential for scale-up production are some of the highlighted advantages of this transformation., (Copyright © 2024, Li et al.)

Even though natural products or crops have been more common and popular in the recent, the chemicals without side-effects have been also addressed in various fields of industries due to possibility obtaining the large quantity and more bio-efficacy. In that context, many drugs have been developed for antibacterial activities but the over-uses of those relevant drugs have caused that microorganisms have adapted and evolved resistance against those drugs. Those lead to the researchers to focus on newly synthesized or functionalized molecules. In that context, nanotechnology, especially modified nanocarbon tubes (NCTs), are of the great interest of the various industries. Along with the current study, multi-walled carbon nanotubes (MWCNTs) were functionalized with three steps. Firstly, the carbon nanotube with a carboxylic acid tip on its surface was commercially purchased and then converted into acyl chloride, and later converted into a more reactive group. Then, the nucleophilic amino group such as diethylene triamine is bonded onto the carbon nanotube. Finally, after the carbon nanotube material with amine groups was functionalized with boric acid, carbon nanotube molecules carrying boric acid molecules were synthesized. Following modification and functionalization of MWCNTs, the newly synthesized molecules were characterized using FT-IR, SEM, TEM and XPS. After chemical characterization, the relevant molecules were screened for their anti-bacterial activities in comparison to those of well-known antibiotics. For anti-bacterial assays, molecules were tested against K. pneumoniae, E. coli, P.aeruginosa, S. aureus and B. subtilis. Concerning the findings of the antibacterial assays, concentrations of 40 and 80 μg /mL exhibited a range of activities but in parallel with those of standard antibiotics whereas the lower concentration, viz. 5, 10 and 20 μg / mL did not exhibit any activities. The highest activity was noted for 80 μg / mL, in comparison to those of antibiotics and other concentrations, against B. subtilis, with a 23 mm inhibition zone. [ABSTRACT FROM AUTHOR]

• Thermal degradation of primary amines was studied experimentally and computationally. • Results show that the primary amines follow a similar thermal degradation mechanism. • The amine loss during the experiment was ranked as: AMB > MEA > 2-AP > 1-AP > AMP. • The ring closure is the limiting step in the thermal degradation of primary amine. • The methyl group at β-carbon hinders the ring closure reaction of 1AP. CO 2 loaded amine polymerizes during solvent regeneration at temperatures above 100 °C, resulting in the deterioration of solvent performance. Herein, five primary amines were heated to 120, 135 and 150 °C with CO 2 loading of 0.4C/N to study thermal degradation. It was found that 2-amine-1-butanol showed the greatest amine loss of 38.5 % after heating to 135 °C for 672 hrs while 2-amino-2-methyl-1-propanol was most stable with amine loss of 17.4 % under the same conditions. The degradation products were identified and the reaction pathway was studied through density functional theory (DFT) calculation. Furthermore, the transition state for ring closure and opening reactions was analyzed. The ring closure reaction to form oxazolidinones had a higher energy barrier, showing that it was the limiting step. This is further supported by the good agreement with experimental results. The structure–activity relationship showed the strong steric hindrance effect and the methyl group at β-carbon improved the amine stability. [ABSTRACT FROM AUTHOR]

A series of hydrotalcite‐derived nickel catalysts were synthesized and employed for the direct amination of biomass‐based furfuryl alcohol with NH3 via the hydrogen borrowing strategy. The effects of the Ni/Al molar ratio and calcination temperature of the NiAl hydrotalcite‐like precursors on the performance of the NixAl‐CT catalyst were investigated. The systematic characterization showed that the synergistic catalysis of the metal and acid‐base sites was of vital importance for the amination of alcohols. In particular, the Ni2Al‐600 catalyst with high amount of Ni0 sites (1.26 mmol g−1) and suitable density of acid‐base sites (0.71 mmol g−1 and 1.10 mmol g−1, respectively) exhibited the best dehydrogenation capability and therefore excellent catalytic activity. An 84.1 % yield of furfurylamine with complete conversion of furfuryl alcohol was obtained under the reaction conditions of 180 °C and 0.4 MPa NH3 in 36 h. The presence of Ni3N in the spent catalyst, confirmed by XRD, TEM and XPS characterizations, was demonstrated to be responsible for the deactivation of the NixAl‐CT catalyst. In addition, the Ni2Al‐600 catalyst exhibited satisfactory performance toward another important biomass‐related transformation of 5‐(aminomethyl)‐2‐furanmethanol to 2,5‐bis(aminomethyl)furan, with a yield of 70.5 %. [ABSTRACT FROM AUTHOR]

Novel and efficient multicomponent reactions (MCRs) involving diketene, ninhydrin (indane-1,2,3-trione) and one primary amine (3CR) or two different primary amines (4CR) were achieved for the successful synthesis of dihydro-4H-indeno[1,2-b]furan-3-carboxamides or tetrahydroindeno[1,2-b]pyrrole-3-carboxamides, respectively. The merits of this method are highlighted by using either commercially available or easily accessible starting materials, operational simplicity, facile workup procedure, efficient usage of all the reactants, tolerance of a variety of functional groups and ability to conduct under un-catalyzed reaction condition. The products were also isolated by just decantation of the solvent, and for the purification column chromatography was non-required. [ABSTRACT FROM AUTHOR]

While imines are frequently used substrates in asymmetric Brønsted acid catalysis, their corresponding salts are generally considered unsuitable reaction partners. Such processes are challenging because they require the successful competition of a catalytic amount of a chiral anion with a stoichiometric amount of an achiral one. We now show that enantiopure disulfonimides enable the asymmetric reduction of N–H imine hydrochloride salts using Hantzsch esters as hydrogen source. Our scalable reaction delivers crystalline primary amine salts in great efficiency and enantioselectivity and the discovery suggests potential of this approach in other Brønsted acid catalyzed transformations of achiral iminium salts. Kinetic studies and acidity data suggest a bifunctional catalytic activation mode. [ABSTRACT FROM AUTHOR]

A series of molybdenum(0), (I) and (II) complexes ligated by different PNP and NNN pincer ligands were synthesized and structurally characterized. Along with previously described Mo−PNP complexes Mo‐1 and Mo‐2, all prepared compounds were tested in the catalytic hydrogenation of aromatic nitriles to primary amines. Among the applied catalysts, Mo‐1 is particularly well suited for the hydrogenation of electron‐rich benzonitriles. Additionally, two aliphatic nitriles were transformed into the desired products in 80 and 86 %, respectively. Moreover, catalytic intermediate Mo‐1a was isolated and its role in the catalytic cycle was subsequently demonstrated. [ABSTRACT FROM AUTHOR]

In this work, a novel method for assigning the absolute configuration of a chiral primary amine has been developed based on the experimental and DFT-calculated 19F NMR chemical shift differences of its derived two fluorinated amides by reacting with two enantiomers of a chiral derivatizing agent FPP (α-fluorinated phenylacetic phenylselenoester) separately. Comparing the experimental chemical shift difference Δδα-FR,S of (R)-FPA-amide/(S)-FPA-amide with the calculated Δδα-FR,S of (R)-FPA-(R)-amide/(S)-FPA-(R)-amide, if the experimental Δδα-FR,S has the same symbol (positive or negative) as one of the theoretical Δδα-FR,S, the assigned configuration of the amine is considered to be consistent with the theoretical one. Our method could be applied to a broad substrate scope avoiding wrong conclusion due to empirical judgment.

Effect of metal nature on reductive amination was investigated with biomass‐based furfural as a typical substrate. Among the tested heterogeneous metal catalysts, cobalt proved to be the most effective metal for the synthesis of the corresponding primary amine. Under a relatively mild reaction condition, 98.9 % yield of furfurylamine was obtained over Raney Co and it can be reused more than eight times without a significant decrease in the catalytic performance. By extensively studying the catalytic pathways and reaction mechanism, it is found that the selectivity to primary amine and secondary amine was governed by the relative rate of hydrogenolysis and hydrogenation of the Schiff base intermediate. The superiority of Raney Co in furfurylamine synthesis can be ascribed to its high efficiency on hydrogenolysis of the Schiff base intermediate and its low performance in the hydrogenation of the Schiff base, carbonyl group and furan ring. Furthermore, ammonia greatly promoted the catalytic hydrogenolysis of the Schiff base intermediate over Raney Co without clear deactivation of the metal active sites. [ABSTRACT FROM AUTHOR]

A homogeneous liquid-liquid microextraction procedure based on primary amine phase separation was developed as a novel approach for the pretreatment of biological fluids. The procedure assumes primary amine dissolution in the aqueous sample phase, resulting in the creation of a homogeneous sample solution followed by phase separation and analyte extraction in the presence of a polar, water-miscible organic solvent. The phenomenon of primary amine phase separation from homogeneous aqueous solution in the presence of a polar, water-miscible organic solvent was studied in detail and applied for separation and preconcentration in chemical analysis for the first time. The suggested approach was used for the HPLC-UV determination of meropenem as a proof-of-concept analyte in human plasma and serum samples. Under optimal conditions, the detector response of meropenem was linear in the concentration range of 0.1–100.0 mg L−1. The limit of detection was calculated from a blank test based on 3σ, was 0.03 mg L−1. • Fast, cheap and efficient approach for sample pretreatment. • Liquid-liquid microextraction based on primary amine phase separation. • Primary amine phase separation from homogeneous solution investigation. • Polar solvent as initiator of primary amine phase separation. • 1-octylamine as extraction solvent for meropenem. • HPCL-UV determination of meropenem using proposed approach. [ABSTRACT FROM AUTHOR]

In this work, a series of novel organocatalysts derived from unique unnatural β‐amino acid scaffold were synthesized and further developed to enhance the desired catalytic properties. Their evaluation was carried out in the asymmetric crossed‐aldol condensation of isatin and enolizable ketone donors. Following a systematic study of the reaction parameters including variations of additive, solvent, temperature, catalyst loading and substrate scope, (1R,2R)‐2‐amino‐N‐((R)‐1‐phenylethyl)cyclohexane carboxamide 9 proved particularly successful, affording the corresponding 3‐hydroxy‐3‐alkyl‐2‐oxindole in excellent yield (>99%) and distereoselectivity (>99% dr) with good enantioselective control (up to 52% ee) in the presence of p‐nitrophenol and EtOH in <24 h. An added benefit of this catalyst was its catalytic activity and selectivity at room temperature eliminating the requirement of reduced reaction temperatures. This scaffold, comprising of β‐amino amide, has not yet been applied in organocatalysis, thus, this is the first reported in this growing area. In mechanistic studies, direct infusion ESI‐MS proved a valuable tool forproposal of the catalytic cycle, confirming the formation of 2 key reaction intermediates. [ABSTRACT FROM AUTHOR]

Highlights • The primary amine (–NH 2) was chemically modified on the hyper-cross-linked polymers (HCLPs). • The adsorption of salicylic acid (SA) on the chemically modified HCLPs was evaluated. • The uploaded –NH 2 groups are greatly helpful for the equilibrium adsorption. • Multiple interactions such as acid-base interaction and hydrogen bonding are driving forces. • The hierarchical microporous and mesoporous structure are favorable for the kinetic adsorption. Abstract Chemically functionalized hyper-cross-linked polymers (HCLPs) are desired for efficient adsorption of aromatic compounds. Herein primary amine (–NH 2) was indirectly functionalized on the HCLPs and the aniline-modified HCLPs namely An-HCLP was assessed by adsorption of salicylic acid from aqueous solution. The results indicated that 2.24 mmol·g−1 of –NH 2 groups were uploaded and they are greatly beneficial for the adsorption, the enthalpy change was figured out to be −35.27 kJ·mol−1, and multiple interactions including acid-base interaction and hydrogen bonding are the main driving forces. Moreover, An-HCLP owned hierarchical porosity with continuous micropores and mesopores, which endowed them with fast kinetic adsorption, 55 min is sufficient for the adsorption attaining equilibrium, and the pseudo-second-order rate equation describes the kinetic very well with the kinetic constant (k 2) of 1.266 × 10−3 g·mg−1·min−1. [ABSTRACT FROM AUTHOR]

Graphical abstract The divergent route was used to prepare a highly branched dendrimer with terminal symmetric amine groups on the surface of SiO 2 -Al 2 O 3 mixed-oxide nanoparticles to serve as an adsorbent of salicylic acid. Abstract The aim of this work is to evaluate the uptake of salicylic acid (SA), an emerging pollutant, using a nano-polar dendrimer containing highly branched terminal symmetric amine groups immobilized on mixed-oxide nanoparticles of SiO 2 -Al 2 O 3. Several variables, including the effect of initial SA concentration, contact time, temperature, initial pH, adsorbent dosage, interfering ions, and the hydrophobicity of the adsorbent (SANP-G1.0) were studied. Because of the electrostatic and hydrogen bonding interactions between SA and the amine functional sites of the nano-polar dendrimer, the adsorbent featured a remarkable SA uptake capacity of over 254.5 mg/g after 5 min contact time. The solution pH had a considerable impact on SA uptake by SANP-G1.0, with optimal uptake occurring around pH 2–5. Kinetic and isotherm studies confirmed that SA removal could be fit with the Sips and pseudo-second-order kinetic models, respectively, implying that a chemical process dominates SA uptake by the SANP-G1.0. The uptake of SA decreased at elevated temperature, demonstrating that this is a chemically and naturally exothermic process between 15 and 80 °C. The uptake efficiency of the reused nanodendrimer was 54% after the tenth adsorption-desorption cycle. Moreover, the SANP-G1.0 showed a high capacity for adsorbing SA from Cayuga Lake water. We studied the possible mechanism of SA uptake, including the effect of interfering ions, using zeta potential, X-ray photoelectron spectroscopy, infrared spectroscopy, and the hydrophobicity of the nanodendrimer. The prepared supported dendrimer, featuring high chemical and mechanical stability, demonstrates good reusability for SA adsorption from aqueous media. An artificial neural network (ANN) model was also designed to simulate SA uptake by SANP-G1.0. The results revealed an excellent fit between the ANN-modeled and experimental data, with a correlation coefficient (R2) of 0.9841. [ABSTRACT FROM AUTHOR]

In this study, a simple and appropriate procedure for the synthesis of functionalized benzothiadiazine 1,1-dioxide with good yields via the Cu-catalyzed intramolecular C-H activation reaction from benzenesulfonylchloride and N,N′,N′′-trisubstitutedguanidines, generated by copper(II) oxide-catalyzed hydroamination of carbodiimides, is reported. [ABSTRACT FROM AUTHOR]

• The Pd-Ni oxide nanoclusters within S-1 exhibited excellent activity for nitrile base-free hydrogenation. • The yield of benzylamine achieved 92% with a TON of 1667. • Upscaling reaction of 500 mg benzonitrile also gave a benzylamine yield of 92%. • The key success factor was the cooperative interaction of bimetallic Pd-Ni species. The selective hydrogenation of nitrile represents an atom-economical and reliable method to synthesize primary amine, a privileged compound in chemistry, biology, and medicine. However, this approach often displays severe selectivity issues, and additives or reducing agents are generally required to solve this problem. In this work, we aim to synthesize primary amine on a green catalytic system and probe into the catalytic mechanism of Pd-Ni interaction using benzonitrile (BN) as a model compound. The nitrile hydrogenation reaction was catalyzed by bimetallic Pd-Ni oxide nanospecies confined in Silicalite‑1 (S-1) zeolite using H 2 as hydrogen donor without any additive which was environmentally friendly and economic. A 92% yield of benzylamine (BA) was achieved on the Pd0.6Ni@S-1 catalyst with a turnover number (TON) of 1667, and such BA yield was still maintained in upscaling experiment. Detailed characterizations shed light on the mechanism of the extraordinary performance of Pd-Ni oxide nanospecies on base-free nitrile hydrogenation. [ABSTRACT FROM AUTHOR]

Starting from primary amine bearing cyclic carbonate tert-butyl-(2-oxo-1,3-dioxan-5-yl) carbamate (TBODC) and caprolactone (CL), amphiphilic poly(caprolactone-ran-amino trimethyl carbonate)s (P(CL-ran-ATC)s) random copolymers with controlled molecular weight and composition were synthesized via ring opening polymerization (ROP) and deprotection, using stannous octoate (Sn(Oct)2) as catalyst and benzyl alcohol (BnOH) as initiator. Therefore, hydrophilic/lipophilic ratio (HLR) of the P(CL-ran-ATC)s copolymers can be finely adjusted by the feed ratio of TBODC and CL. The antimicrobial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) of P(CL-ran-ATC)s were proportional to HLR, and P(CL-ran-ATC)s presented more vigorous bactericidal activity towards S. aureus. The minimum inhibitory concentration (MIC) values of P(CL-ran-ATC 50.9%) are 2000 μg mL−1 and 3000 μg mL−1 for S. aureus and E. coli. While P(CL-ran-ATC 50.9%) exhibited deficient hemolytic activity as 1.41%. In addition, the P(CL-ran-ATC)s showed extremely low cytotoxicity towards fibroblast L929 cells.

1-(Substituted-1-ylmethyl)indoline-2,3-dione 1a-c have been synthesized from different types of secondary amine with isatin and formaldehyde in alcohol. The compound 1 have then been converted to the respective compound 2a-g (Z)3-(4- subsitutedphenylimino)-1-(substituted-1-ylmethyl)indolin-2-one by treatment with different types of primary amines. Interaction of compound 2 with thioglycolic acid and chloro acetyl chloride results in cyclization to give compound spiro isatin derivatives compounds 3a-g. The anti-microbial activity screening of novel spiro isatin substituted compounds have also been carried out. [ABSTRACT FROM AUTHOR]