Amination Of Aldehydes Research Articles

Catalyst-free reductive amination of aromatic aldehydes with ammonium formate and Hantzsch ester

The protocol of the reductive amination of aromatic aldehydes using ammonium formate and Hantzsch ester is described. It is a mild, convenient, acid- and catalyst-free system applied for the synthesis of both symmetric and asymmetric aromatic secondary amines.

Green synthesis and catalytic properties of palladium nanoparticles for the direct reductive amination of aldehydes and hydrogenation of unsaturated ketones

This paper reports on the synthesis and use of palladium nanoparticles as heterogeneous catalysts for the reductive amination of aldehydes and hydrogenation of unsaturated ketones. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered and reused several times without significant loss of catalytic activity.

ChemInform Abstract: Reductive Amination of Aldehydes and Amines with an Efficient Pd/NiO Catalyst.

AbstractThe Pd/NiO catalyst exhibits excellent activity and selectivity in the reductive amination reaction using a wide range of amines and aldehydes as substrates.

Oligonucleotide Analogues with Integrated Bases and Backbone. Part 32

AbstractThe G[s]G dinucleoside 6 and the G[s]G* dinucleoside 8 were prepared by alkylation of the guanosine thiols derived from 2 and 5, respectively, by the C(8)‐chloromethylated guanosine 4 that was obtained from alcohol 3. Dinucleosides 6 and 8 were deacylated to 7 and 9, and fully deprotected to 10 and 11, respectively. The G[n]G dinucleoside 16 was obtained by reductive amination of aldehyde 13 with an iminophosphorane derived from azide 14 and deprotection of the resulting dimer 15. In the solid state of 6, and in a solution of 6 and 8 in CDCl3, HN(1/I) and HN(1/II) are engaged in intramolecular H‐bonds to the CO of the isobutyryl protecting groups, and HN of the isobutyryl group of unit I forms an interresidue, intramolecular H‐bond to N(7/II), leading to a syn orientation of the nucleobase at unit I, to a tg orientation of the sulfanyl moiety, and to an orthogonal orientation of the nucleobases, preventing any base pairing. The silylated and isopropylidenated dinucleosides 7 and 9 are present in DMSO solution as solvated monoplexes. Broad 1H‐NMR signals of the nucleosides 7 and 16 in CHCl3 solution evidence equilibrating G‐quadruplexes. The quadruplex formation of 7 and 16 was established by 1H‐NMR spectroscopy (only of 16), vapour pressure osmometry, mass spectrometry, and CD spectroscopy. The C(6(I))‐hydroxymethylated analogue 9 in CDCl3 and the fully deprotected dinucleosides 10 and 11 in H2O form only weakly ππ stacked associates, but no G‐quadruplexes, as evidenced by CD spectroscopy.

A two-component pre-seeded dermal–epidermal scaffold

We have developed a bilayered dermal–epidermal scaffold for application in the treatment of full-thickness skin defects. The dermal component gels in situ and adapts to the lesion shape, delivering human dermal fibroblasts in a matrix of fibrin and cross-linked hyaluronic acid modified with a cell adhesion-promoting peptide. Fibroblasts were able to form a tridimensional matrix due to material features such as tailored mechanical properties, presence of protease-degradable elements and cell-binding ligands. The epidermal component is a robust membrane containing cross-linked hyaluronic acid and poly-l-lysine, on which keratinocytes were able to attach and to form a monolayer. Amine–aldehyde bonding at the interface between the two components allows the formation of a tightly bound composite scaffold. Both parts of the scaffold were designed to provide cell-type-specific cues to allow for cell proliferation and form a construct that mimics the skin environment.

Oligonucleotide Analogues with Integrated Bases and Backbone (ONIB). Part 31

AbstractThe self‐complementary guanosine‐ and cytidine‐derived aminomethylene‐linked C*[n]G dinucleoside 9 was synthesized by reductive amination of aldehyde 3 with an iminophosphorane derived from azide 7. Deacylation of 9 gave the isopropylidene‐protected dinucleoside 10. The sequence‐isomeric G*[n]C dinucleoside 11 was similarly prepared from aldehyde 8 and azide 5, and deacylated to 12. The association of 10 and 12 in CHCl3 or in CHCl3/DMSO mixtures, and the structure of the associates were studied by 1H‐NMR, ESI‐MS, CD, and vapor pressure osmometry (VPO). Broad 1H‐NMR signals of dinucleosides 10 and 12 evidence an equilibrium between duplexes and quadruplexes (Hoogsteen base pairing between the WatsonCrick base‐paired duplexes). The quadruplex dominates for the G*[n]C dinucleoside 12 between −50° and room temperature. The sequence‐isomeric C*[n]G 10 forms mostly only a cyclic duplex in CDCl3 and in CDCl3/(D6)DMSO 9 : 1.

Ruthenium-Catalyzed Direct Reductive Amination in HCOOH/NEt3 Mixture

A one-pot direct reductive amination of aldehydes with primary and secondary amines using Noyori’s catalyst (η 6-arene)Ru(H)TsDPEN in neat HCOOH/NEt3 mixture has been developed. The catalyst formed in situ allows full conversion of aldehydes with high selectivities towards the desired amine products within hours or even minutes at room temperature. For aromatic aldehydes, both 5:2 and 5:3 HCOOH/NEt3 mixtures prove to be suitable reaction media, with the former affording higher selectivities while the latter leading to much faster reaction rates. For aliphatic aldehydes, the 5:3 HCOOH/NEt3 mixture gives much higher selectivities due to the minimal loss from aldol condensation. This method has great application potential for the synthesis of amine products given the mild conditions.

ChemInform Abstract: Palladium on Activated Carbon Catalyzed Reductive Amination of Aldehydes and Ketones by Triethylsilane.

Various aldehydes and ketones were efficiently transformed into the corresponding amines using amine derivatives in the presence of triethylsilane and a catalytic amount of palladium on activated carbon in ethanol. The proposed method provides a one-pot synthesis of various amines in excellent yields after short reaction times. Copyright © 2013 John Wiley & Sons, Ltd.

Polymer Supported Triphenylphosphine-Palladium Acetate Complex PS-TPP-Pd(OAc)2 as a Heterogeneous and Reusable Catalyst for Indirect Reductive Amination of Aldehydes

Indirect reductive amination of aldehydes, catalyzed by polymer supported triphenylphosphine-palladium acetate complex PS-TPP-Pd(OAc)2 catalyst have been developed. The imine is prepared with molecular sieves in the first stage, followed by reduction with potassium formate catalyzed by PS-TPP-Pd(OAc)2. The recovered catalyst could be reused for four consecutive cycles without loss in activity and provided an excellent yield of the desired products.

Aqueous-phase catalytic oxidation, transfer hydrogenation, reductive amination and hydration reactions

As part of our work devoted to the synthesis of organic compounds using “green” processes, we developed several water-soluble catalysts that allow efficiently the synthesis of ketones, amines, alcohols and amides. CuCl2·2H2O combined to 2,2′-biquinoline-4,4′-dicarboxylic acid dipotassium salt (BQC) was reported as an active catalyst for the selective oxidation with TBHP of alcohols, alkylarenes and alkynes. We developed also successfully hydrogen transfer reactions. While [Ir(COD)Cl]2/BQC proved to be efficient for Oppenauer-type oxidation of secondary alcohols, [Rh(COD)Cl]2/P(m-C6H4SO3Na)3 (TPPTS) showed very good activities for Meerwein–Ponndorf–Verley-type reduction of ketones and aldehydes. Higher alkylated amines and amides were also synthesized respectively, by direct reductive amination of aldehydes with primary and secondary amines catalyzed by water soluble Pd(PhCN)2Cl2/BQC, and hydration of nitriles with [Rh(COD)Cl]2/TPPTS. Many of these catalytic systems are recycled with no significant loss of activity and the final products are isolated in easy manners.

A one-pot parallel reductive amination of aldehydes with heteroaromatic amines.

A parallel reductive amination of heteroaromatic amines has been performed using a combination of ZnCl2-TMSOAc (activating agents) and NaBH(OAc)3 (reducing agent). A library of diverse secondary amines was easily prepared on a 50-300 mg scale.

Preparation and characterization of melamine/formaldehyde/polyethylene glycol crosslinking copolymers as solid–solid phase change materials

A kind of solid–solid phase change materials (SSPCMs), melamine/formaldehyde/polyethylene glycols (MFPEG) crosslinking copolymers, was synthesized referring to the reaction mechanism and conditions of amine–aldehyde condensation reaction and aldolization. The composition and chemical structure, thermophysical and crystallographic properties of MFPEG crosslinking copolymers were investigated by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance spectrometer (1H NMR), differential scanning calorimetry (DSC), thermogravimetry analysis system (TGA), wide-angle X-ray diffraction (WXRD) and polarization optical microscopy (POM). The results indicate that MFPEGs crosslinking copolymers possess excellent phase change properties and an applicable temperature range. The maximal latent heat enthalpies of heating and cooling cycle are 109.4 and 103.9J/g, respectively. The decomposing temperature range of MFPEGs is about 340–455°C in nitrogen atmosphere.

Reductive Amination of Aldehydes and Amines with an Efficient Pd/NiO Catalyst

By applying a simple Pd/NiO catalyst, the reductive amination of amines and aldehydes can progress efficiently under mild reaction conditions, and 24 substituted amines with different structures were synthesized with up to 98% isolated yields.

Reductive amination of aldehydes and ketones catalyzed by deep eutectic solvent using sodium borohydride as a reducing agent

Different derivatives of aldehydes/ketones were subjected under reductive amination reaction in the presence of ChCl/Urea as a green and biocompatible catalyst. Sodium borohydride was used as a reducing agent. Secondary amines were achieved with high selectivities and yields.

ChemInform Abstract: Efficient and Chemoselective Direct Reductive Amination of Aromatic Aldehydes Catalyzed by Oxo—Rhenium Complexes Containing Heterocyclic Ligands.

Abstract This work describes the catalytic activity of 17 oxo–rhenium complexes containing heterocyclic ligands in the direct reductive amination of 4-nitrobenzaldehyde with 4-chloroaniline, using phenylsilane as reducing agent. In general, all of the catalysts tested gave excellent yields of the secondary amine, although, the best result was obtained with the catalytic system PhSiH3/ReOBr2(Hhmpbta)(PPh3) (2.5 mol %). This system was also applied to the synthesis of a large variety of secondary amines in good to excellent yields and tertiary amines in moderate yields, with tolerance of different functional groups.

ChemInform Abstract: Reductive Amination of Tertiary Anilines and Aldehydes.

An unprecedented oxidant-mediated reductive amination of tertiary anilines and aldehydes without external reducing agents was developed via the nucleophilic attack of the oxygen atom of the carbonyl group to in situ generated iminium ions, in which tertiary anilines were used as both nitrogen source and reducing agent for the first time.

Ultrasonic and Lewis acid ionic liquid catalytic system for Kabachnik-Fields reaction

AbstractA combination of ultrasonic (US) and [bmim]AlCl4 ionic liquid is used as an alternative to conventional acid catalysts in the Kabachnik-Fields reaction of an amine and aryl aldehyde with phosphite leading to the formation of aminophosphonates. The reaction time was significantly reduced and the reaction progressed very smoothly.

Microwave-Assisted Synthesis and Characterization of Certain Oximes, Hydrazones, and Olefins Derived fromβ-Keto Sulfones

A new series ofβ-keto sulfone derivatives containing oximes4a–e, hydrazones5a, b, and chalcones7a–dwere prepared using microwave irradiation (MWI) by the reaction ofβ-keto sulfones3with hydroxyl amine, hydrazines, and aromatic aldehydes, respectively. The comparative study between microwave irradiation and conventional syntheses showed that MWI is effective in the synthesis of the title compounds through shortening of the reaction time and improvements in their yields. The structures of the synthesized compounds were established under the basis of their spectral data and X-ray single crystal analysis of compound5a. The crystal of5abelongs to triclinic space groupP-1, witha=5.7735 (2) Å,b=9.3224 (3) Å,c=13.1696 (5) Å,α=76.411 (1)°,β=89.571 (1)°,γ=79.9380 (9)°,Z=2, V=677.97 (4) Å3,Dc=1.513 Mg m−3,μ=0.44 mm−1,F(000)=320,R=0.026, andwR=0.070for 2690 observed reflections withI>2σ(I).

Silica nanosphere-supported palladium(ii) furfural complex as a highly efficient and recyclable catalyst for oxidative amination of aldehydes

The present work reports the fabrication of a novel and highly efficient silica nanospheres-based palladium catalyst (SiO2@APTES@Pd-FFR) via immobilization of a palladium complex onto silica nanospheres functionalized with 3-aminopropyltriethoxysilane (APTES), and its catalytic application for the oxidative amination of aldehydes to yield commercially important amides. The structure of the nano-catalyst was confirmed by Solid-state (13)C CPMAS and (29)Si CPMAS NMR spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FT-IR), Energy dispersive X-ray fluorescence spectroscopy (ED-XRF), Atomic absorption spectroscopy (AAS), Transmission electron microscopy (TEM) and elemental analysis. The nano-catalyst was found to be highly effective for the oxidative amination of aldehydes using hydrogen peroxide as an environmentally benign oxidant to give amides. The effect of various reaction parameters such as temperature, amount of catalyst, reaction time, type of solvent, oxidant used, substrate to oxidant ratio etc. have been demonstrated to achieve high catalytic efficacy. Moreover, this nanostructured catalyst could be recovered with simplicity and reused for several cycles without any significant loss in its catalytic activity. In addition, the stability of the reused nano-catalyst was proved by FT-IR and HRTEM techniques. It is worth noting that the features of mild reaction conditions, simple work-up procedure, high product yield, no use of toxic organic solvents, high turn-over frequency (TOF), and easy recovery and reusability of the present quasi-homogeneous nano-catalyst make this protocol an attractive alternative to the existing catalytic methods for the oxidative amination of aldehydes to furnish industrially important amides.

Light-responsive fluorescent cross-linked polymeric micelles based on a salicylidene Schiff base pendant-functionalized block copolymer

A well-defined block copolymer polystyrene-block-poly(2-hydroxy-5-vinylbenzaldehyde) (PS-b-PHVB) was synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization of HVB using a trithiocarbonate terminated polystyrene macro-chain transfer agent. Sequential grafting of monoamine-terminated PEG (PEG–NH2) and 2-(2-aminoethoxy)ethanol (AME) onto the HVB blocks of PS-b-PHVB via aldehyde–amine condensation afforded an amphiphilic block copolymer PS-b-(PHVB-g-PEG-and-AME) bearing a pendant salicylidene Schiff base with a precise structure. PS-b-(PHVB-g-PEG-and-AME) could self-assemble in ethanol into micelles with salicylidene Schiff base groups at the core–shell interface. Addition of Zn2+ ions into the resulting micellar solution not only endowed the micelles with fluorescent features but also enabled the resulting luminescent micelles to be stabilized through ionic cross-linking in consequence of the salicylaldimine–Zn2+ complexation. The obtained fluorescent cross-linked micelle was “light-controllable” in terms of its fluorescence emission and cross-linking structure due to the reversibility of the salicylaldimine–Zn2+ coordinative bond in response to light stimuli. The reversible fluorescence decrease and recovery could be achieved periodically upon alternative 254 nm UV irradiation and maintaining in the dark, and the micelles could be de-stabilized by UV irradiation-induced de-cross-linking. The capture of guest molecules and the light-triggered release of the guests for this Zn2+ coordinated micelle were also demonstrated using the coumarin-153 dye as a model guest molecule.