Alkylamines Research Articles

Metallaphotocatalytic triple couplings for modular synthesis of elaborate N-trifluoroalkyl anilines.

The integration of trifluoromethyl groups and three-dimensional quaternary carbon moieties into organic molecules has emerged as a prominent strategy in medicinal chemistry to augment drug efficacy. Although trifluoromethyl (hetero)aromatic amines and derivatives are prevalent frameworks in pharmaceuticals, the development of trifluoromethyl-embedded, intricately structured alkyl amine scaffolds for medicinal research remains a significant challenge. Herein, we present a metallaphotoredox multicomponent amination strategy employing 3,3,3-trifluoropropene, nitroarenes, tertiary alkylamines, and carboxylic acids. This synthetic pathway offers notable advantages, including the accessibility and cost-effectiveness of starting materials, high levels of chemo- and regioselectivity, and modularity. Furthermore, this approach enables the synthesis of a broad spectrum of aniline compounds featuring both trifluoromethyl group and distal quaternary carbon motifs along the aliphatic chains. The accelerated access to such elaborate N-trifluoroalkyl anilines likely involves three sequential radical-mediated coupling events, providing insightful implications for the retrosynthesis of potential compounds in organic synthesis and drug discovery.

Copper‐Catalyzed Tandem Cyclization of 2‐(Alkynylaryl)Acetonitriles and Amines: Access to 3‐Hydroxyisoindolinones

AbstractHerein, we describe an approach to the synthesis of 3‐hydroxyisoindolinone derivatives via copper‐catalyzed tandem cyclization of 2‐(alkynylaryl)acetonitriles and amines. This reaction is compatible with 2‐(alkynylaryl)acetonitriles and primary alkyl amines containing various functional groups, providing the corresponding 3‐hydroxyindolinone derivatives with yields ranging from 44%–82%. Preliminary mechanistic studies suggest that the reaction involves oxidation of the benzylic carbon, amide formation, hydration of the alkyne and intramolecular cyclization to produce various 3‐hydroxyisoindolinones. The practicality of the strategy was further demonstrated by gram‐scale synthesis, late‐stage functionalizations, and the post modification of natural products.

Selective C6‐Nitration of Benzothiazolones with Iron Nitrate

AbstractWe report here a selective C6‐nitration of benzothiazolones in the presence of iron nitrate as nitro source. A series of novel 6‐nitrobenzothiazolin‐2‐one derivatives were prepared with moderate to excellent yields at room temperature. The method shows good regioselectivity, broad substrate scope and excellent compatibility with functional groups. Further transformations were performed for the reduction of nitro groups, amination of carbonyl groups and alkylation of amine at the 3‐position in the product.

Synthesis and characterization of a series of amidine-based switch surfactants: toward environmental surface-active materials

A series of newly structured two-tailed cationic surfactants were synthesized via a carbonyl amine condensation reaction aimed at reducing the bioaccumulation of conventional surfactants while maintaining their excellent surface properties. Long-chain alkyl amine compounds can be reversibly converted into charged surfactants through CO2/H2O treatment and an alkyl chain length of between C8 and C12. The structures were characterized by IR,1H NMR and 13C NMR. The main surface activity parameters of the surfactants, containing cmc, γcmc pC20, cmc/С20, Γm and Αmin, were determined. The switching properties of N’-alkyl-N, N-dimethylalkamidine bicarbonate and N, N-dimethyl-N-alkylamidine bicarbonate were demonstrated by investigating their conductivities in solution and carrying out their emulsification-emulsion-breaking experiment.

Intermolecular crosslinking of phenols and alkyl amines with formaldehyde in HFIP for conjugation: A multi-partner bridging model for HFIP promotion

Intermolecular crosslinking of phenols and alkyl amines with formaldehyde in HFIP for conjugation: A multi-partner bridging model for HFIP promotion

Substrate and Product Selective Supramolecular Catalysis by Pillar[5]arene in the Alkylation of Primary Linear Amines with Allyl Bromide

Substrate and Product Selective Supramolecular Catalysis by Pillar[5]arene in the Alkylation of Primary Linear Amines with Allyl Bromide

Synergistic adsorption mechanism of novel combined collector in flotation separation of fayalite from magnetite: Experiments and MD simulations

As an iron-bearing silicate mineral, fayalite has similar surface properties to magnetite, which makes it challenging to efficiently separate fayalite from magnetite by flotation. In this study, magnetite and fayalite were separated using novel combined collector polyoxyethylene alkyl amine (PAE) and terpinol (AT) through reverse flotation. Combined with a variety of characterization analysis and molecular dynamics (MD) simulation, the synergistic adsorption mechanism of the combined collector on mineral surface was revealed from multiple perspectives. The optimum scheme and pH response range of the combined collector were determined by micro-flotation test. Compared with PAE alone, the difference value of flotation recovery between fayalite and magnetite using combined collector was increased by 10.16%, and the dosage was reduced by 20%. Additionally, an effectively adsorption of combined collector onto fayalite surface to improve its surface hydrophobicity. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and MD simulations results showed synergistic adsorption was produced onto fayalite surface using combined collector mainly through non-polar interaction, hydrogen bond association and bridge adsorption. Furthermore, the spatial distribution and diffusion behavior of water molecules provide microscopic evidence for the enhancement of surface hydrophobicity of fayalite by combined collector.

Mobile Phase Contaminants Affect Neutral Lipid Analysis in LC-MS-Based Lipidomics Studies.

Lipidomics is a well-established field, enabled by modern liquid chromatography mass spectrometry (LC-MS) technology, rapidly generating large amounts of data. Lipid extracts derived from biological samples are complex, and most spectral features in LC-MS lipidomics data sets remain unidentified. In-depth analyses of commercial triacylglycerol, diacylglycerol, and cholesterol ester standards revealed the expected ammoniated and sodiated ions as well as five additional unidentified higher mass peaks with relatively high intensities. The identities and origin of these unknown peaks were investigated by modifying the chromatographic mobile-phase components and LC-MS source parameters. Tandem MS (MS/MS) of each unknown adduct peak yielded no lipid structural information, producing only an intense ion of the adducted species. The unknown adducts were identified as low-mass contaminants originating from methanol and isopropanol in the mobile phase. Each contaminant was determined to be an alkylated amine species using their monoisotopic masses to calculate molecular formulas. Analysis of bovine liver extract identified 33 neutral lipids with an additional 73 alkyl amine adducts. Analysis of LC-MS-grade methanol and isopropanol from different vendors revealed substantial alkylated amine contamination in one out of three different brands that were tested. Substituting solvents for ones with lower levels of alkyl amine contamination increased lipid annotations by 36.5% or 27.4%, depending on the vendor, and resulted in >2.5-fold increases in peak area for neutral lipid species without affecting polar lipid analysis. These findings demonstrate the importance of solvent selection and disclosure for lipidomics protocols and highlight some of the major challenges when comparing data between experiments.

Organocatalytic asymmetric α-C–H functionalization of alkyl amines

Organocatalytic asymmetric α-C–H functionalization of alkyl amines

Visible-Light-Driven Synthesis of N-Alkyl α-Amino Acid Derivatives from Unactivated Alkyl Bromides and In Situ Generated Imines.

One-pot, multicomponent reactions are known for their green and efficient nature. We report a novel three-component reaction of alkyl amines, alkyl glyoxylates, and unactivated alkyl bromides under visible-light-induced palladium catalysis, yielding N-alkyl unnatural α-amino acid derivatives. This method offers mild conditions, broad substrate scope, and excellent functional group tolerance without requiring stoichiometric organometallic reagents. The approach has promising applications in protein engineering and drug discovery.

CO2 capture using functionalized MIL-101(Cr) metal–organic frameworks: Functionality nanoarchitectonics of nanospace for CO2 adsorption

In this study, we investigated the effect of functional groups of metal–organic frameworks (MOFs) on CO2 adsorption at low pressure through experimental and computational approaches. We compared the performance of −SO3H, –NO2, aryl –NH2, and alkyl –NH2 groups (in similar molar quantities) in CO2 adsorption under the same conditions. The adsorption efficiency followed in the order: alkyl –NH2 > -SO3H>aryl –NH2 > –NO2 because of the different adsorption mechanisms over the groups. The main mechanism over alkyl –NH2 was the formation of ammonium carbamate via the carbamic acid formation. The adsorption mechanism over −SO3H and aryl –NH2 groups was Lewis acid-base and H-bonding interactions, while that over –NO2 group was solely Lewis acid-base interaction. The alkyl amine exhibited the best performance (in adsorption capacity, selectivity, and adsorption heat) due to its ability to form carbamate readily. On the contrary, aryl amine demonstrated lower performance than −SO3H groups, attributed to their low capability to form carbamate. These findings underscore the importance of amine type in CO2 adsorption, highlighting that aryl amines, different from alkyl amines, perform worse than other functional groups, such as −SO3H.

Catalyst Free Synthesis of 4‐Aryl/Alkylamino‐1,2‐Naphthoquinones: Applications in Fluorescence Microscopy

AbstractAn efficient one‐step reagent‐free synthesis of 4‐Aryl/alkylamino‐1,2‐naphthoquinones in water and iPrOH (1 : 1) mixture was carried out at room temperature (RT) using 4‐amino‐3‐hydroxynaphthalene‐1‐sulfonic acid and various primary and secondary aryl and alkyl amines. The reaction did not proceed in the absence of air or oxygen. In all cases, good yields (isolated yield: ≥65 %) were observed. The compounds exhibited fluorescence emission bands (400–470 nm) in the visible region upon excitation at their respective λmax values (330–350 nm). We evaluated in vitro cytotoxicity of some of the derivatives against two human breast cancer cell lines (MCF‐7, and MDA‐MB‐231) using the WST‐1 assay. The naphthoquinone derivatives did not show any cytotoxic effects at concentration levels relevant to cellular fluorescence imaging. The imaging experiments revealed that a few of the derivatives hold the potential to be used as cellular fluorescent imaging probes.

Systematic anode engineering enabling universal efficiency improvements in organic solar cells

Anode modification and optimization is crucial towards improving performance of organic solar cells (OSCs). PEDOT:PSS is the most common choice as a hole transport layer (HTL) material, but suffers from issues including low conductivity. In this work, three alkyl amine derivatives - methylamine hydrochloride (MA), ethylamine hydrochloride (EA) and propylamine hydrochloride (PA) are doped into the commercially available Al 4083 PEDOT:PSS to form PEDOT:PSS-MA, PEDOT:PSS-EA and PEDOT:PSS-PA, as modified HTLs. All these modified HTLs exhibit improved chemical and electrical properties including work functions (WF), conductivities and charge carrier motilities. The alkyl amine doping shows compatibility in both Small Molecular Acceptors and All-Polymer OSCs. With PEDOT:PSS-MA demonstrates a highest PCE of 18.49 % compared to the 17.84 % of OSC devices prepared with pristine PEDOT:PSS with the PM6:L8-BO system, while PM6:PY-IT all-polymer OSCs improve PCE from 14.53 % to 15.22 %. AFM characterizations reveal that the introduction of the dopants have smoothened the surface morphology of spin-coated HTL films, which contributes towards more efficient charge extraction. In summary, this study not only presents a method of improving OSC efficiencies, but also provides insight and further possible directions towards anode optimization of OSCs.

Hydride Shuttle Catalysis: From Conventional to Inverse Mode.

Hydride shuttle catalysis has emerged as a powerful synthetic platform, enabling the selective formation of C-C bonds to yield sp3-rich structures. By virtue of the compelling reactivity of sterically encumbered Lewis acids from the frustrated Lewis pair regime, hydride shuttle catalysis enables the regioselective functionalization of alkyl amines at either the α- or β-position. In contrast to classical Lewis acid reactivity, the increased steric hindrance prevents interaction with the Lewis basic amine itself, instead leading to reversible abstraction of a hydride from the amine α-carbon. The created positive charge facilitates the occurrence of transformations before hydride rebound or a similar capture event happen. In this Perspective, we outline a broad selection of transformations featuring hydride shuttle catalysis, as well as the recently developed approach of inverse hydride shuttle catalysis. Both strategies give rise to a wide array of functionalized amines and offer elegant approaches to otherwise elusive bond formations.

Direct synthesis of alkyl amines from dinitrogen and alkenes

In a recent issue of Nature, Hou, Luo and Shima presented a transformative approach for synthesizing alkyl amines, utilizing a trititanium polyhydride framework for the direct hydroamination of alkenes with atmospheric dinitrogen. This method not only bypasses traditional ammonia-dependent processes but also introduces a novel strategy for C–N bond formation under mild conditions. This advancement holds great promise for significant progress in sustainable chemical manufacturing.

1-Iodoglycal: A Versatile Intermediate for the Synthesis of d-Glyco Amides and Esters Employing Carbonylative Cross-Coupling Reaction.

In this study, we present the development of two catalytic processes: a Pd-PEPPSI-catalyzed aminocarbonylation and a Pd(OAc)2-Xantphos-catalyzed alkoxycarbonylation of d-glycals, utilizing carbonylative cross-coupling reactions. We explored successfully various types of aromatic amines, as well as alkyl amines and amino acids, to synthesize new d-glycal amides. However, we observed limitations in the reactivity of alkyl and heteroaromatic amines. The processes enabled the synthesis of 20 novel C1-branched glycoamides and 7 new d-gluco esters.

Iron-Catalyzed Multicomponent C-H Alkylation of in Situ Generated Imines via Photoinduced Ligand-to-Metal Charge Transfer.

Herein, we describe a novel photoinduced iron-catalyzed strategy for multicomponent C-H alkylation of in situ generated imines. By utilizing the alkyl radicals generated through iron-mediated photocatalytic C-H activation, the imines formed in situ are further subjected to addition reactions, resulting in the synthesis of various secondary and tertiary amine products. This method is simple to operate and does not require additional oxidants. It is applicable to inert alkane substrates such as cyclic alkanes, cyclic ethers, toluene, and ketones. The reaction is also compatible with various aromatic amines, alkyl amines, halogenated aromatic amines, as well as aromatic aldehydes, alkyl aldehydes, and cinnamaldehyde, among other different types of aldehydes.

Iron(II)-Catalyzed 1,2-Diamination of Styrenes Installing a Terminal NH2 Group Alongside Unprotected Amines.

1,2-Diamination of alkenes represents an attractive way to generate differentiated vicinal diamines, which are prevalent motifs in biologically active compounds and catalysts. However, existing methods are usually limited in scope and produce diamines where one or both nitrogens are protected, adding synthetic steps for deprotection and further N-functionalization to reach a desired target. Furthermore, the range of amino groups that can be introduced at the internal position is fairly limited. Here we describe a 1,2-diamination of styrenes that directly installs a free amino group at the terminal position and a wide variety of unprotected nitrogen nucleophiles (primary or secondary alkyl or aromatic amines, sulfoximines, N-heterocycles, and ammonia surrogate) at the internal position. Two complementary sets of conditions encompass electronically activated and deactivated styrenes with diverse substitution patterns and functional groups. Moreover, this strategy can be extended to the 1,2-aminothiolation of styrenes.

Iron(II)‐Catalyzed 1,2‐Diamination of Styrenes Installing a Terminal NH2 Group Alongside Unprotected Amines

1,2‐Diamination of alkenes represents an attractive way to generate differentiated vicinal diamines, which are prevalent motifs in biologically active compounds and catalysts. However, existing methods are usually limited in scope and produce diamines where one or both nitrogens are protected, adding synthetic steps for deprotection and further N‐functionalization to reach a desired target. Furthermore, the range of amino groups that can be introduced at the internal position is fairly limited. Here we describe a 1,2‐diamination of styrenes that directly installs a free amino group at the terminal position and a wide variety of unprotected nitrogen nucleophiles (primary or secondary alkyl or aromatic amines, sulfoximines, N‐heterocycles, and ammonia surrogate) at the internal position. Two complementary sets of conditions encompass electronically activated and deactivated styrenes with diverse substitution patterns and functional groups. Moreover, this strategy can be extended to the 1,2‐aminothiolation of styrenes.

Performance of Aromatic Amine-Modified Metallocene Polyalphaolefin Lubricant Base Oil

With the continuous advancement of industrial technology, higher demands have been placed on the properties of gear oils, such as oxidation stability and shear resistance. Herein, the oxidation stability of high-viscosity metallocene poly-α-olefins (mPAOs) was improved by chemical modification via aromatic amine alkylation. The modified mPAO base oils were synthesized separately with diphenylamine (mPAO-DPA) and N-phenyl-α-naphthylamine (mPAO-NPA), and their applicability in industrial gear oil formulations was evaluated. The composition and physicochemical properties of the obtained samples were assessed using 1H NMR spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, and the American Society for Testing and Materials standards (ASTM D445, ASTM D2270, ASTM D92, etc.) confirming the successful completion of the alkylation reaction. The oxidation stability of the samples was also evaluated using pressurized differential scanning calorimetry. The initial oxidation temperature of mPAO-NPA (230 °C) was 53 °C higher than that of mPAO, and the oxidation induction period of mPAO-DPA was nearly twice that of mPAO-NPA. Thermogravimetric analysis in air revealed the increased thermal decomposition temperature and improved thermal stability of modified mPAO. ISO VG 320 industrial gear oils were formulated using mPAO alkylated with N-phenyl-α-naphthylamine(Lub-2) and commercially purchased PAO100 (Lub-1) as base oil components. The antioxidant performance of two industrial gear oils was evaluated through oven oxidation and rotating oxygen bomb tests. The oxidation induction period of Lub-2 was 30% higher than that of Lub-1, with the latter having a lower acid number and a smaller increase in viscosity at 40 °C. Finally, the friction performance of the samples was assessed on a four-ball friction tester, revealing the synergistic effect of the mPAO-NPA base oil with the HiTEC 3339 additive, forming a more stable oil film with a smaller wear scar diameter.