Amination Of Alcohols Research Articles

Molybdenum Complex-Catalyzed N-Alkylation of Bulky Primary and Secondary Amines.

Aliphatic allylic amines are present in a large number of complex and pharmaceutically relevant molecules. The direct amination of allylic electrophiles serves as the most common method toward the preparation of these motifs. However, the use of feedstock reaction components (allyl alcohol and aliphatic amine) in these transformations remains a great challenge. Such a challenge primarily stems from the high Lewis basicity and large steric hindrance of aliphatic amines, in addition to the low reactivity of allylic alcohols. Herein, we report a general solution to these challenges. The developed protocol allows an efficient allylic amination of allyl alcohols with sterically bulky aliphatic amines in the presence of an inexpensive earth-abundant molybdenum complex. This simple and economic protocol also enables regioselective branched amination; the practicality of the reaction was shown in an efficient, scaled-up synthesis of several drugs.

Photochemical generation of ketenes from phenanthrene-based cyclobutanones

Various 9,10-cyclopropanated phenanthrenes have been shown previously to be viable photochemical precursors to many different types of carbenes. There is also one known example in the literature of a related approach used to generate diphenylketene from a phenanthrene-derived cyclobutanone in a laser flash photolysis study. In an effort to broaden the scope of this promising yet under-utilized method of ketene generation, the synthesis and characterization of several phenanthrene-based cyclobutanones, and their subsequent photolysis to produce a variety of ketenes, are presented in this report. The ketenes are produced, along with phenanthrene, by a formal 2 + 2 cyclo-reversion of the cyclobutanone moiety and have been intercepted by benzyl alcohol and benzyl amine to form the corresponding benzyl esters and amides respectively.

Magnetically Induced Amination of Alcohols Using MNi@Cu (M=Fe, Co) Nanoparticles as Catalysts

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

Photocatalytic Direct Para‐Selective C−H Amination of Benzyl Alcohols: Selectivity Independent of Side Substituents

AbstractAminoarenes are important molecules for broad applications in nearly all modern industries that involve chemicals. Direct and site‐selective C−H bond amination of arenes provides the most efficient and convenient method to prepare aminoarenes. A main challenge is to selectively install the amino group (or other functional groups) to the distal para‐carbon of arenes (especially multi‐substituted arenes) during the C−H bond functionalization events. Herein, we address this problem by designing a new strategy via a sequential radical dearomatization/radical amination/rearomatization process for para‐selective amination of benzyl alcohols. The para‐selectivity of our reaction is completely independent of the electronic and steric properties of the other substituents of the arene substrates. Aminoarenes with many substituents (up to full substitution) and diverse substitution patterns, including those difficult to synthesize previously, could be readily prepared using our protocols. Further exploration of the current strategy shall lead to other challenging C−H functionalization of arenes.

Photocatalytic Direct Para-Selective C-H Amination of Benzyl Alcohols: Selectivity Independent of Side Substituents.

Aminoarenes are important molecules for broad applications in nearly all modern industries that involve chemicals. Direct and site-selective C-H bond amination of arenes provides the most efficient and convenient method to prepare aminoarenes. A main challenge is to selectively install the amino group (or other functional groups) to the distal para-carbon of arenes (especially multi-substituted arenes) during the C-H bond functionalization events. Herein, we address this problem by designing a new strategy via a sequential radical dearomatization/radical amination/rearomatization process for para-selective amination of benzyl alcohols. The para-selectivity of our reaction is completely independent of the electronic and steric properties of the other substituents of the arene substrates. Aminoarenes with many substituents (up to full substitution) and diverse substitution patterns, including those difficult to synthesize previously, could be readily prepared using our protocols. Further exploration of the current strategy shall lead to other challenging C-H functionalization of arenes.

Current Status of Amine Dehydrogenases: From Active Site Architecture to Diverse Applications Across a Broad Substrate Spectrum

AbstractAmine 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.

Chiral ferrocenylimine alcohols and corresponding reduced ferrocenyl secondary amine alcohols: synthesis, X-crystal structures and characterization

Chiral ferrocenylimine alcohols and corresponding reduced ferrocenyl secondary amine alcohols: synthesis, X-crystal structures and characterization

Asymmetric Amination of Primary Alcohols via Dynamic Kinetic Resolution: Enantioconvergent Access to Chiral Benzomorpholines

Asymmetric Amination of Primary Alcohols via Dynamic Kinetic Resolution: Enantioconvergent Access to Chiral Benzomorpholines

Employing Ammonia for the Synthesis of Primary Amines: Recent Achievements over Heterogeneous Catalysts.

Primary amines represent highly privileged chemicals for synthesis of polymers, pharmaceuticals, agrochemicals, coatings, etc. Consequently, the development of efficient and green methodologies for the production of primary amines are of great importance in chemical industry. Owing to the advantages of low cost and ease in availability, ammonia is considered as a feasible nitrogen source for synthesis of N-containing compounds. Thus, the efficient transformation of ammonia into primary amines has received much attention. In this review, the commonly applied synthetic routes to produce primary amines from ammonia were summarized, including the reductive amination of carbonyl compounds, the hydrogen transfer amination of alcohols, the hydroamination of olefins and the arylation with ammonia, in which the catalytic performance of the recent heterogeneous catalysts is discussed. Additionally, various strategies to modulate the surface properties of catalysts are outlined in conjunction with the analysis of reaction mechanism. Particularly, the amination of the biomass-derived substrates is highlighted, which could provide competitive advantages in chemical industry and stimulate the development of sustainable catalysis in the future. Ultimately, perspectives into the challenges and opportunities for synthesis of primary amines with ammonia as N-resource are discussed.

Magnetically Induced Amination of Alcohols Using MNi@Cu (M=Fe, Co) Nanoparticles as Catalysts.

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

C(sp3)-N Bond Formation via Deoxygenative Amination of Alcohols

C(sp3)-N Bond Formation via Deoxygenative Amination of Alcohols

Primary Allylic Amine Synthesis via Pd-Catalyzed Direct Amination of Allylic Alcohols with Ammonium Acetate.

Pd/DPEphos-catalyzed direct amination of allylic alcohols with readily available ammonium acetate as a nitrogen source provides access to convenient and scalable syntheses of primary allylic amines with high monoallylation selectivity. Mechanistic studies revealed that ammonium acetate functions as a Brønsted acid to activate the hydroxyl groups and inhibit overreaction.

Preparation and Rheological Properties of the PVA/CMC/Gel Composite for Mining.

A composite gel material with an interpenetrating network structure was formed using the chemical cross-linking method. The viscosity, yield stress, and thixotropy of a poly(vinyl alcohol)/carboxymethyl cellulose/gelatin (PVA/CMC/Gel) composite gel slurry with different ratios were tested using a viscometer, and the interaction between the surface of the gelling agent and the cross-linking agent was analyzed by calculating the frontline orbital energy of a single polymer material molecule. The seepage diffusion characteristics of the composite gel in a goaf were then studied through a numerical simulation. The results indicate that the PVA/CMC/Gel composite gel exhibits shear thinning behavior following the power law model and behaves as a pseudoplastic fluid. The optimal ratio for the composite gel at 30 °C is determined as follows: 30 wt % for the gelling agent (PVA/(Gel + CMC) = 20:10), 4 wt % for the cross-linking agent, 3.09 wt % for the carbide slag, 7.5 wt % for the alcohol amine solution, and 0.5% sodium dodecyl sulfonate + 0.1% alkyl glycoside for the foaming agent. Gel exhibits the lowest energy band gap (0.096 eV), indicating strong reaction activity and strong reaction with the cross-linking agent (sodium tetraborate). PVA has the largest energy band gap (0.238 eV), strong molecular stability, and weak reaction with the cross-linking agent (sodium tetraborate). When the dip angle of the goaf is 4° and the injection time is 40 min, the composite gel tends to diffuse more easily along the dip. The investigation into the rheological properties of the PVA/CMC/Gel composite gel holds significant importance in the design of coal mine pipeline transportation and understanding diffusion flow in goaf.

Molecular dynamics study of the anticorrosive lubricating effects and interfacial behavior of dicarboxylic acid alcohol amine

In this study, water-soluble additives with excellent performance were designed, and their anticorrosive, tribological characteristics, and antibacterial properties were evaluated. Combined with molecular dynamics (MD), the interfacial behavior of additives on metal surfaces was investigated at the atomic scale. The results showed that the additive molecules could reduce the wear rate of ethylene glycol aqueous (EGaq) by 94.7 %, exhibiting excellent anticorrosive efficiency while also possessing certain antibacterial properties. MD results indicated that the additive could firmly adhere to the metal surface due to its higher electron transfer rate, and the interfacial interaction energy increased with the extension of the carbon chain. The coexistence of longer alkyl chains and frictionally active elements ensured the overall stability of the adsorption film.

Free-Radical Deoxygenative Amination of Alcohols via Copper Metallaphotoredox Catalysis.

Alcohols are among the most abundant chemical feedstocks, yet they remain vastly underutilized as coupling partners in transition metal catalysis. Herein, we describe a copper metallaphotoredox manifold for the open shell deoxygenative coupling of alcohols with N-nucleophiles to forge C(sp3)-N bonds, a linkage of high value in pharmaceutical agents that is challenging to access via conventional cross-coupling techniques. N-heterocyclic carbene (NHC)-mediated conversion of alcohols into the corresponding alkyl radicals followed by copper-catalyzed C-N coupling renders this platform successful for a broad range of structurally unbiased alcohols and 18 classes of N-nucleophiles.

Metal-acid synergistic catalysis accelerates the hydrogen borrowing amination of alcohols by confining Ru sites in Beta zeolite

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.

Selective amination of furfuryl alcohol to furfurylamine over nickel catalysts promoted by alumina encapsulation

Direct amination of bio-based furfuryl alcohol over metal catalysts provides an alternative route to produce furfurylamine without consuming expensive reducing reagents. The harsh and reductive condition of furfuryl alcohol amination, however, requires high durability and excellent resistance to side furan-ring hydrogenation for efficient catalysts, which is still substantially challenging to non-noble metals. We show here that alumina-encapsulated Ni catalysts prepared via a sol–gel method exhibited an outstanding and stable performance in selective amination of furfuryl alcohol to furfurylamine under mild NH3 and H2 partial pressures. Structural characterization unveiled that the alumina framework with appropriate mesopores effectively restrained the agglomeration of Ni nanoparticles and the side furan-ring hydrogenation. A volcano-type dependance of the intrinsic activity of Ni nanoparticles on their sizes was established with the maximum attained at about 5 nm, which correlated well with the redox ability of surface Ni sites. Kinetic assessments further indicated the kinetic relevance of furfural formation from furfuryl alcohol dehydrogenation, evidenced by quasi-zero and negative reaction orders on NH3 and H2 pressures, respectively. Combined with infrared spectroscopy, furfuryl alcohol was identified as the predominant adsorbed species with a nearly saturated coverage under reaction condition, consistent with the high susceptibility of furan-ring hydrogenations to H2 pressure. As a consequence, a slight amount of inert Ag (0.05 wt%) was introduced onto the alumina-encapsulated Ni catalysts to weaken the adsorption of furfuryl alcohol and its derivatives, which suppressed the side over-hydrogenation reactions to an extremely low level without sacrificing catalytic activity significantly.

Recent Advances in Catalytic Systems for the Reduction of Aromatic and Aliphatic Nitrile Compounds to Amines.

Amines are important and valuable compounds widely used in the chemical industry to produce various products such as dyes, detergents, solvents, additives, pharmaceutical products, and anti-foam agents. A property that distinguishes primary amines from other compounds is their straightforward functionalization. Therefore, the synthesis of different amine compounds has been considered by many researchers in recent years. Usually, primary amines are produced via amination of alcohols, reductive amination, and reduction of nitro and amide compounds. Furthermore, a useful and atom-economical method for producing primary amines is reducing nitrile compounds using catalytic systems. Traditionally, nitriles are reduced using metal hydrides such as LiAlH4 or NaBH4. These methods have important restrictions in terms of selectivity and waste generation. Hence, the heterogeneous and homogeneous catalysts were investigated for the hydrogenation of nitriles to diverse amines. This review describes the performance of different catalytic systems for reducing nitrile compounds to their corresponding amines.

Direct N‐Alkylation of Amines with Alcohols Catalyzed by N‐Heterocyclic Carbene Cobalt‐Pincer Catalyst under Mild Conditions

AbstractAlcohols are widely available and can be derived from renewable resources. Catalytic alcohol amination for N‐alky amine synthesis using the borrowing hydrogen strategy is an environmentally benign and prominent sustainable method, which produces water as the sole byproduct. However, expensive noble metals are generally employed for this transformation, while the nonprecious metal‐based catalysts were also known for this reaction and have attracted considerable attention recently. Herein, an efficient N‐alkylation of amines with alcohols using base‐metal cobalt catalysts is reported. This reaction is catalyzed by an N‐heterocyclic carbene cobalt‐pincer catalyst and the reaction operates simply and under mild conditions. Various alcohol and aniline substrates and functional groups including nitrile, ether, thioether and alkene could be well tolerated. Moreover, experimental studies and DFT calculations were also performed to illustrate the reaction mechanism. Our results suggest that the N‐alkylation reaction proceeds via a hydrogen autotransfer mechanism.

Three-Component Transformation of CO 2 , Propargyl Alcohols and Secondary Amines into β-Oxopropylcarbamates Promoted by a Noble Metal-Free Metal–Organic Framework Catalyst

Three-Component Transformation of CO ₂ , Propargyl Alcohols and Secondary Amines into β-Oxopropylcarbamates Promoted by a Noble Metal-Free Metal–Organic Framework Catalyst