Primary Alkylamines Research Articles

Supramolecular Synthon Approach in Designing Organic Sulfonates as Supramolecular Gelators: An Easily Accessible Topical Gel with Antibacterial Properties

The supramolecular synthon approach in the context of the crystal engineering rationale has been exploited to synthesize a new series of primary ammonium sulfonate salts derived from primary alkyl amines with varying alkyl chain lengths (An = CH3–(CH2)n–NH2; n = 2–11, 13–15, 17) and naphthalene-2-sulfonic acid (N2S) as potential supramolecular gelators. The sulfonate salts AnN2S with n ≥ 9 showed the ability to immobilize a number of polar and nonpolar solvents including dimethyl sulfoxide/water, resulting in supramolecular gels which were characterized by dynamic rheology and transmission electron microscopy. Single-crystal X-ray diffraction studies carried out on eight such salts confirmed the presence of gel-inducing hydrogen bonded supramolecular synthons. Anti-bacterial studies (zone inhibition, turbidity, and tetrazolium assays) revealed that the salt A14N2S had the ability to kill the Gram-positive bacterium Staphylococcus aureus. Laser scanning confocal microscopy and flow cytometry data taken under various staining conditions suggested reactive oxygen species-mediated RNA depletion as the plausible cause of bacterial cell death in the presence of the gelator salt. Shear thinning of the aqueous gel of A14N2S along with its anti-bacterial activity indicated that it could be a potential candidate for topical application.

Novel Bis[N-alkyl-N-(2-diphenylphosphinylethyl)]diglycolamides: Synthesis and NMR Spectroscopy Studies

Pentadentate bis[N-alkyl-N-(2-diphenylphosphinylethyl)]diglycolamides [Ph2P(O)CH2CH2N(R)· C(O)CH2]2O, where R Me, Bu, Oct, were synthesized by reaction of diglycolyl chloride with N-alkyl-N-(2-diphenylphosphinylethyl)amines Ph2P(O)CH2CH2NHR obtained by reacting diphenyl(2-phenoxyethyl)phosphine oxide with primary alkylamines in DMSO in the presence of an aqueous alkali. Structure of the prepared compounds was studied by 1H, 13C, and 31P NMR spectroscopy.

Exploring reactions of amines-model compounds with NH2: In relevance to nitrogen conversion chemistry in biomass

Amine-containing compounds (primary/NH2, secondary/NH and heterocyclic –NH) -are principal nitrogenated species in biomass. Amine radical (NH2) emerge as an important intermediate in the initial stages of biomass combustion and pyrolysis. A detail understanding of the nitrogen conversion chemistry necessitates acquiring accurate reaction rate constants for reactions of NH2 radicals with amine-bearing molecules. With the absence of relevant kinetic parameters, pertinent kinetic model on oxidation of surrogate biomass compounds often utilize values extracted from analogous reactions with OH and CH3 radicals. Herein, we report comprehensive kinetic parameters for H abstraction by NH2 radicals from various C/H sites in seventeen amine model compounds, comprising primary/secondary alkyl and aromatic amines. Fitted activation energies were found to linearly correlate with N–H bond dissociation enthalpies via Evans–Polanyi plots. In primary C2-C4 alkylamines and in diethylamine, abstraction from the α C–H site (gem to the amine group) largely dominates that from the NH2 group. Abstraction from NH and methyl sites in dimethylamine entails comparable importance. A vinylic CH2 group does not alter kinetics of abstraction for unsaturated amines when contrasted with primary amines. Reaction rate constants for H abstraction from heterocyclic-NH structures follow the order carbazole > indole > pyrrole, reflecting corresponding BDHs values for their N–H bonds. Updating kinetic models on combustion of small amines structures, with the newly calculated reaction rate constants, slightly improves their predictive performance toward the yields of NH2/NH3.

Manganese Catalyzed Direct Amidation of Esters with Amines.

The transition metal catalyzed amide bond forming reaction of esters with amines has been developed as an advanced approach for overcoming the shortcomings of traditional methods. The broad scope of substrates in transition metal catalyzed amidations remains a challenge. Here, a manganese(I)-catalyzed method for the direct synthesis of amides from a various number of esters and amines is reported with unprecedented substrate scope using a low catalyst loading. A wide range of aromatic, aliphatic, and heterocyclic esters, even in fatty acid esters, reacted with a diverse range of primary aryl amines, primary alkyl amines, and secondary alkyl amines to form amides. It is noteworthy that this approach provides the first example of the transition metal catalyzed amide bond forming reaction from fatty acid esters and amines. The acid-base mechanism for the manganese(I)-catalyzed direct amidation of esters with amines was elucidated by DFT calculations.

Aziridination of Internal Alkenes Using Primary Alkyl Amines in a Microflow Electrocell

Aziridines are versatile synthetic intermediates en route to structurally diverse and complex nitrogen-containing molecules. In this issue of <i>Chem</i>, Noël and co-workers report the aziridination of internal alkenes with primary alkyl amines through novel electrochemical activation with hydrogen gas generated as the byproduct, assisted by a microflow electrocell.

Reframing primary alkyl amines as aliphatic building blocks.

While primary aliphatic amines are ubiquitous in natural products, they are traditionally considered inert to substitution chemistry. This review highlights historical and recent advances in the field of aliphatic deamination chemistry which demonstrate these moieties can be harnessed as valuable C(sp3) synthons. Cross-coupling and photocatalyzed transformations proceeding through polar and radical mechanisms are compared with oxidative deamination and other transition metal catalyzed reactions.

Adsorption of alkylamines on Cu surfaces: identifying ideal capping molecules using first-principles calculations.

We used dispersion-corrected density-functional theory to perform an in silico search over a series of primary alkylamines, including linear, branched, and cyclic molecules, to identify capping molecules for shape-selective Cu nanocrystal synthesis. We identify several attributes associated with successful capping agents. Generally, molecules with good geometric matching to the Cu surfaces possessed the strongest molecule-surface chemical bonds. However, non-bonding van der Waals interactions and molecular packing constraints can play a more significant role in determining the overall binding energy, the surface coverage, and the likely efficacy of the capping molecule. Though nearly all the molecules exhibited stronger binding to Cu(100) than to Cu(111), all predicted Wulff shapes are primarily {111}-faceted, based on ab initio thermodynamics calculations. From predicted capping-molecule densities on Cu(100) and Cu(111) for various solution environments, we identified several candidate molecules to produce {100}- or {111}-faceted nanocrystals with kinetic shapes, based on synthesis conditions used to grow Cu nanowires with ethylenediamine capping agent. Our study reveals the complexity of capping-molecule binding and important considerations that go into the selection of a successful capping agent.

Electrochemical Aziridination of Internal Alkenes with Primary Amines

<h2>Summary</h2> Aziridines are useful synthetic building blocks, widely employed for the preparation of various nitrogen-containing derivatives. As the current methods require the use of prefunctionalized amines, the development of a synthetic strategy toward aziridines that can establish the union of alkenes and amines would be of great synthetic value. Herein, we report an electrochemical approach, which realizes this concept via an oxidative coupling between alkenes and primary alkylamines. The reaction is carried out in an electrochemical flow reactor leading to short reaction/residence times (5 min), high yields, and broad scope. At the cathode, hydrogen is generated, which can be used in a second reactor to reduce the aziridine, yielding the corresponding hydroaminated product. Mechanistic investigations and DFT calculations revealed that the alkene is first anodically oxidized and subsequently reacted with the amine coupling partner.

γ-Amino phosphonates via the photocatalytic α-C–H alkylation of primary amines

Abstract We report a simple photocatalytic protocol for the direct synthesis of γ-amino phosphonates via the α-C–H alkylation of unprotected, aliphatic primary amines with diethyl vinylphosphonate. These motifs are valuable bioisosteres of γ-amino acids and O-phosphorylated amino alcohols. Visible-light photoredox catalysis in combination with hydrogen atom transfer (HAT) catalysis is used to access the necessary α-amino radical intermediates for C–C bond formation. The procedure is also demonstrated on gram-scale in continuous flow for the synthesis of a racemic, protected derivative of the mGlu agonist 2-amino-4-phosphonobutyric acid (AP4).

Applications of primary alkylamines in nanoparticles formation and stabilization

Fatty amines or primary alkyl-amines like hexylamine, Octylamine, Decylamine, Dodecylamine, Tetradecylamine, Hexadecylamine, and Octadecylamine have been used widely in nanoparticles formation, preparation and for stabilization issue; due to their low toxicity and easily utility. The most common use of fatty amines in many research work that has been reviewed is as capping and stabilizing agent for the nanoparticles, and that is related to their abilities to stabilize nanoparticles and reduce Ostwald ripening after nanoparticles formation. Moreover, Fatty amines surfactants have been reported in many research works to assist the formation of monodisperse size because they can be adsorbed on the surface of nanoparticles which limit variability in nanoparticles size and also they can form a coat around nanoparticles that prevent agglomeration or aggregation of nanoparticles. Also, other uses that have been addressed for fatty amines as they served as hydrophobic part due to hydrocarbon chain tail. These tails for fatty amines especially those with long hydrocarbon chain more than 12 carbons like; Dodecylamine C12, tetradecylamine C14, hexadecylamine C16 and octadecylamine C18 can be fabricated and conjugated with other molecules or polymers for many nanoparticles synthesis which can help in the self-assembly of nanoparticles. Moreover, due to their high boiling point; they used as solvents and reaction catalyst facilitate the formation of nanoparticles. Finally, fatty amines surfactant used as the ligating compound also assist the formation of nanoparticles.

Aryl C(sp2)-X Coupling (X = C, N, O, Cl) and Facile Control of N-Mono- and N,N-Diarylation of Primary Alkylamines at a Pt(IV) Center.

We present the first example of an unprecedented and fast aryl C(sp2)–X reductive elimination from a series of isolated Pt(IV) aryl complexes (Ar = p-FC6H4) LPtIVF(py)(Ar)X (X = CN, Cl, 4-OC6H4NO2) and LPtIVF2(Ar)(HX) (X = NHAlk; Alk = n-Bu, PhCH2, cyclo-C6H11, t-Bu, cyclopropylmethyl) bearing a bulky bidentate 2-[bis(adamant-1-yl)phosphino]phenoxide ligand (L). The C(sp2)–X reductive elimination reactions of all isolated Pt(IV) complexes follow first-order kinetics and were modeled using density functional theory (DFT) calculations. When a difluoro complex LPtIVF2(Ar)(py) is treated with TMS–X (TMS = trimethylsilyl; X= NMe2, SPh, OPh, CCPh) it also gives the corresponding products of the Ar–X coupling but without observable LPtIVF(py)(Ar)X intermediates. Remarkably, the LPtIVF2(Ar)(HX) complexes with alkylamine ligands (HX = NH2Alk) form selectively either mono- (ArNHAlk) or diarylated (Ar2NAlk) products in the presence or absence of an added Et3N, respectively. This method allows for a one-pot preparation of diarylalkylamine bearing different aryl groups. These findings were also applied in unprecedented mono- and di-N-arylation of amino acid derivatives (lysine and tryptophan) under very mild conditions.

Synthesis of β-Diamine Building Blocks by Photocatalytic Hydroamination of Enecarbamates with Amines, Ammonia and N-H Heterocycles.

3‐Amino‐substituted saturated nitrogen heterocycles are an important subclass of β‐diamines, appearing in a number of clinical agents. Herein, we report a unified approach to these products based upon the regioselective photoredox‐mediated hydroamination of enecarbamates. The amine coupling partner can encompass diverse amine types under a single set of reaction conditions, including primary alkyl amines, ammonia, aryl and heteroaryl amines, and N−H heterocycles. The method enables the synthesis of a wide range of pharmaceutically relevant building blocks.

Luminescent Colloidal InSb Quantum Dots from In Situ Generated Single-Source Precursor.

Despite recent advances, the synthesis of colloidal InSb quantum dots (QDs) remains underdeveloped, mostly due to the lack of suitable precursors. In this work, we use Lewis acid–base interactions between Sb(III) and In(III) species formed at room temperature in situ from commercially available compounds (viz., InCl3, Sb[NMe2]3 and a primary alkylamine) to obtain InSb adduct complexes. These complexes are successfully used as precursors for the synthesis of colloidal InSb QDs ranging from 2.8 to 18.2 nm in diameter by fast coreduction at sufficiently high temperatures (≥230 °C). Our findings allow us to propose a formation mechanism for the QDs synthesized in our work, which is based on a nonclassical nucleation event, followed by aggregative growth. This yields ensembles with multimodal size distributions, which can be fractionated in subensembles with relatively narrow polydispersity by postsynthetic size fractionation. InSb QDs with diameters below 7.0 nm have the zinc blende crystal structure, while ensembles of larger QDs (≥10 nm) consist of a mixture of wurtzite and zinc blende QDs. The QDs exhibit photoluminescence with small Stokes shifts and short radiative lifetimes, implying that the emission is due to band-edge recombination and that the direct nature of the bandgap of bulk InSb is preserved in InSb QDs. Finally, we constructed a sizing curve correlating the peak position of the lowest energy absorption transition with the QD diameters, which shows that the band gap of colloidal InSb QDs increases with size reduction following a 1/d dependence.

Selective Pd-Catalyzed Monoarylation of Small Primary Alkyl Amines through Backbone-Modification in Ylide-Functionalized Phosphines (YPhos).

Ylide-substituted phosphines have been shown to be excellent ligands for C–N coupling reactions under mild reaction conditions. Here we report studies on the impact of the steric demand of the substituent in the ylide-backbone on the catalytic activity. Two new YPhos ligands with bulky ortho-tolyl (pinkYPhos) and mesityl (mesYPhos) substituents were synthesized, which are slightly more sterically demanding than their phenyl analogue but considerably less flexible. This change in the ligand design leads to higher selectivities and yields in the arylation of small primary amines compared to previously reported YPhos ligands. Even MeNH2 and EtNH2 could be coupled at room temperature with a series of aryl chlorides in high yields.

Nickel-Catalyzed Amination of (Hetero)aryl Halides Facilitated by a Catalytic Pyridinium Additive.

An efficient and operationally simple Ni-catalyzed amination protocol has been developed. This methodology features a simple NiII salt, an organic base and catalytic amounts of both a pyridinium additive and Zn metal. A diverse number of (hetero)aryl halides were coupled successfully with primary and secondary alkyl amines, and anilines in good to excellent yields. Similarly, benzophenone imine gave the corresponding N-arylation product in an excellent yield.

Transition-Metal-Catalyzed Reductive Amination Employing Hydrogen.

The reductive amination, the reaction of an aldehyde or a ketone with ammonia or an amine in the presence of a reducing agent and often a catalyst, is an important amine synthesis and has been intensively investigated in academia and industry for a century. Besides aldehydes, ketones, or amines, starting materials have been used that can be converted into an aldehyde or ketone (for instance, carboxylic acids or organic carbonate or nitriles) or into an amine (for instance, a nitro compound) in the presence of the same reducing agent and catalyst. Mechanistically, the reaction starts with a condensation step during which the carbonyl compound reacts with ammonia or an amine, forming the corresponding imine followed by the reduction of the imine to the alkyl amine product. Many of these reduction steps require the presence of a catalyst to activate the reducing agent. The reductive amination is impressive with regard to the product scope since primary, secondary, and tertiary alkyl amines are accessible and hydrogen is the most attractive reducing agent, especially if large-scale product formation is an issue, since hydrogen is inexpensive and abundantly available. Alkyl amines are intensively produced and use fine and bulk chemicals. They are key functional groups in many pharmaceuticals, agro chemicals, or materials. In this review, we summarize the work published on reductive amination employing hydrogen as the reducing agent. No comprehensive review focusing on this subject has been published since 1948, albeit many interesting summaries dealing with one or the other aspect of reductive amination have appeared. Impressive progress in using catalysts based on earth-abundant metals, especially nanostructured heterogeneous catalysts, has been made during the early development of the field and in recent years.

Photocatalytic α-Tertiary Amine Synthesis via C–H Alkylation of Primary Amines

Photocatalytic α-Tertiary Amine Synthesis via C–H Alkylation of Primary Amines

Synthesis and Characterization of Fatty Acid Amides from Commercial Vegetable Oils and Primary Alkyl Amines for Phase Change Material Applications

The feasibility of synthesizing bio-based fatty acid amides for phase change material (PCM) applications was studied. Fatty acid amides (FAAms) were successfully synthesized from commercial vegetable oils and primary alkyl amines. The chemical structures of the samples were characterized through FTIR, ¹H-NMR, and ¹³C-NMR, while their thermal properties were studied using DSC and TGA. Results show the potential of FAAms synthesized from corn and sunflower oils to be used as PCMs, which exhibited single transitions over narrow temperature ranges upon cooling/heating even when no fractionation or separation of the material was carried out. The melting temperature of the FAAms increased with the length of the precursor amine, and a similar trend was observed for latent heat except for FAAms from hexadecylamine. Latent heats of the synthesized materials were as high as 141 kJ/kg, and all the FAAms were thermally stable under 200 °C.

Reaction of Amines with NO at room temperature and atmospheric pressure: is nitroxyl a reaction intermediate?

Abstract The novelty of this work lies in the experimental confirmation that alkylamines react with Nitric oxide (NO) in aqueous solution at room temperature and atmospheric pressure conditions releasing HNO. We combined spectroscopic, electrochemical, and kinetic techniques to describe the reactions intermediates and characterized end products determined by UV–vis, NMR, and GC-MS. Nitrosamine and propene were detected for the reactions of diethylamine and isopropylamine, showing differential mechanisms between primary and secondary alkylamines. Finally, mechanistic analysis using ab-initio methods was performed and compared with the molecular mechanism proposed for the decomposition of NONOates. The results are discussed in the context of the growing interest in the NO/HNO interconversion reactions, required to understand their overlapping and different reactivity.

Palladium-Catalyzed Oxidation of β-C–H Bonds of Primary Alkylamines

Key words palladium catalysis - oxidation - alkylamines - DFT calculations