Secondary Aliphatic Amines Research Articles

Silver(I)(Pyridine-Containing Ligand)] Complexes As Unusual Catalysts for A3-Coupling Reactions

Two original macrocyclic silver(I)(pyridine-containing ligand) complexes [Ag(I)(Pc-L)] were synthesized and characterized. Their ability to catalyze the coupling among aldehydes, terminal alkynes and amines (A(3)-coupling) was demonstrated. The reaction could be performed under conventional as well as dielectric heating. The catalysts were effective in both cases, but dielectric heating allowed a lower catalyst loading and reduced ratio among reaction partners in shorter reaction times. The reaction scope was broad, including aryl/alkyl aldehydes, aryl/alkyl acetylenes and secondary aliphatic amines. Some unprecedented propargylamines have been prepared. The new catalytic system was also tested with more challenging coupling partners such as aniline and ketones.

Synthesis of monofluoroalkenes using a Pt-catalyzed amination reaction of cyclic 3,3-difluoropropenes with secondary aliphatic amines

The synthesis of monofluoroalkenes using a Pt-catalyzed amination reaction of cyclic 3,3-difluoropropenes is reported. The use of secondary aliphatic amines and cyclic 3,3-difluoropropenes is necessary for the success of the reaction.

Proposed chemical mechanisms leading to secondary organic aerosol in the reactions of aliphatic amines with hydroxyl and nitrate radicals

The presence and importance of amines in the atmosphere, including aliphatic amines, continues to gain more attention. The atmospheric reaction mechanisms of these amines with key atmospheric radicals are important to predict both daytime and nighttime atmospheric chemistry. While previous studies have focused on the production of amine salts, this analysis looks at the importance of peroxy radical reactions to the formation of secondary organic aerosol. Atmospheric oxidation mechanisms are presented to explain the observed chemistry. A series of environmental chamber experiments were conducted in which aliphatic tertiary and secondary amines were reacted with either hydroxyl radical (OH) or nitrate radical (NO3). Chemical composition of the aerosol products was obtained with a High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a Particle Into Liquid Sampler Time of Flight Mass Spectrometer (PILS-ToF-MS), while the chemical composition of the gas-phase products was obtained with a Selected Ion Flow Tube Mass Spectrometer (SIFT-MS). A number of aerosol-phase mass spectra showed highly oxidized fragments at a much higher molecular weight (MW) than the amine precursor. It is proposed that these larger compounds are oligomers formed through peroxy radical reactions with hydrogen rearrangement. Another reaction pathway observed was the formation of amine salts. The relative importance of each pathway to the overall production of aerosol is found to be dependent on the type of amine and oxidant. For example, the oligomers were observed in the tertiary methyl amines, while the formation of amine salts was more prevalent in the secondary and tertiary ethyl amines.

Aliphatic amine discrimination by pentafluorophenyl dibromo BODIPY.

Two new fluorescent BODIPY dyes have been designed and synthesized. They dyes differ in their meso substituents, which have different electronic properties. Their selective reactivity towards an Ar-S(N)2 reaction has been explored as a potential basis for colorimetric and fluorescent discrimination of primary, secondary and tertiary aliphatic amines. This dual-mode, instantaneous recognition event is unprecedented.

Palladium-catalysed C-H activation of aliphatic amines to give strained nitrogen heterocycles.

The development of new chemical transformations based on catalytic functionalization of unactivated C-H bonds has the potential to simplify the synthesis of complex molecules dramatically. Transition metal catalysis has emerged as a powerful tool with which to convert these unreactive bonds into carbon-carbon and carbon-heteroatom bonds, but the selective transformation of aliphatic C-H bonds is still a challenge. The most successful approaches involve a 'directing group', which positions the metal catalyst near a particular C-H bond, so that the C-H functionalization step occurs via cyclometallation. Most directed aliphatic C-H activation processes proceed through a five-membered-ring cyclometallated intermediate. Considering the number of new reactions that have arisen from such intermediates, it seems likely that identification of distinct cyclometallation pathways would lead to the development of other useful chemical transformations. Here we report a palladium-catalysed C-H bond activation mode that proceeds through a four-membered-ring cyclopalladation pathway. The chemistry described here leads to the selective transformation of a methyl group that is adjacent to an unprotected secondary amine into a synthetically versatile nitrogen heterocycle. The scope of this previously unknown bond disconnection is highlighted through the development of C-H amination and carbonylation processes, leading to the synthesis of aziridines and β-lactams (respectively), and is suggestive of a generic C-H functionalization platform that could simplify the synthesis of aliphatic secondary amines, a class of small molecules that are particularly important features of many pharmaceutical agents.

ChemInform Abstract: BippyPhos: A Single Ligand with Unprecedented Scope in the Buchwald—Hartwig Amination of (Hetero)aryl Chlorides.

AbstractIn addition cross couplings of arylchlorides and diamines as well as secondary aliphatic amines are described.

Solventless oxidative coupling of amines to imines by using transition-metal-free metal-organic frameworks.

A highly efficient, simple, and versatile transition-metal-free metal-organic framework catalytic system is proposed for the oxidative coupling of amines to imines. The catalytic protocol features high activities and selectivities to target products; compatibility with a variety of substrates, including aliphatic amines and secondary amines; and the possibility to efficiently and selectively promote amine cross-coupling reactions. A high stability and recyclability of the catalyst is also observed under the investigated conditions. Insights into the reaction mechanism indicate the formation of a superoxide species able to efficiently promote oxidative couplings.

Copper-catalyzed intermolecular C-H amination of (hetero)arenes via transient unsymmetrical λ³-iodanes.

A one-pot two-step method for intermolecular C-H amination of electron-rich heteroarenes and arenes has been developed. The approach is based on a room-temperature copper-catalyzed regioselective reaction of the in situ formed unsymmetrical (hetero)aryl-λ(3)-iodanes with a wide range of primary and secondary aliphatic amines and anilines.

Sustainable heterogeneous platinum catalyst for direct methylation of secondary amines by carbon dioxide and hydrogen.

Pt and MoO(x) co-loaded TiO2 is found to be highly effective for direct methylation of aliphatic and aromatic secondary amines by CO2 and H2 under solvent-free conditions. This is the first additive-free and reusable heterogeneous catalytic system with acceptable turnover number.

CMO1 encodes a putative choline monooxygenase and is required for the utilization of choline as the sole nitrogen source in the yeast Scheffersomyces stipitis (syn. Pichia stipitis)

Sixteen yeasts with sequenced genomes belonging to the ascomycete subphyla Saccharomycotina and Taphrinomycotina were assayed for their ability to utilize a variety of primary, secondary, tertiary and quartenary aliphatic amines as nitrogen sources. The results support a previously proposed pathway of quaternary amine catabolism whereby glycine betaine is first converted into choline, which is then cleaved to release trimethylamine, followed by stepwise demethylation of trimethylamine to release free ammonia. There were only a few instances of utilization of N-methylated glycine species (sarcosine and N,N-dimethylglycine), which suggests that this pathway is not intact in any of the species tested. The ability to utilize choline as a sole nitrogen source correlated strongly with the presence of a putative Rieske non-haem iron protein homologous to bacterial ring-hydroxylating oxygenases and plant choline monooxygenases. Deletion of the gene encoding the Rieske non-haem iron protein in the yeast Scheffersomyces stipitis abolished its ability to utilize choline as the sole nitrogen source, but did not affect its ability to use methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, ethanolamine or glycine as nitrogen sources. The gene was named CMO1 for putative choline monooxygenase 1. A bioinformatic survey of eukaryotic genomes showed that CMO1 homologues are found throughout the eukaryotic domain.

ChemInform Abstract: Synthesis of Some Novel α‐Cyanoketene‐N,S‐acetals (III) Derived from Secondary Aliphatic Amines and Their Use in Pyrazole Synthesis.

ChemInform Abstract: Synthesis of Some Novel α‐Cyanoketene‐N,S‐acetals (III) Derived from Secondary Aliphatic Amines and Their Use in Pyrazole Synthesis.

Inhibition of corrosion and hydrogen permeation into carbon steel in solutions containing hydrogen sulphide and carbon dioxide

The efficiency of ethoxy higher aliphatic amines (EOAs) against carbon dioxide and hydrogen sulphide corrosion and hydrogen permeation into carbon steel in acid solutions has been studied. The influence of the number of ethoxy groups (2, 5 and 14), the length of the hydrocarbon radical (R = C10 – C13 and R = C17 – C20), medium acidity (0.005–0.05 M HCl), and electrode potential was investigated. Concurrently, the influence of higher aliphatic amine bottoms (emulgin) that are a mixture of primary and secondary aliphatic amines was studied. The protective efficiency of EOAs reaches 95–99.9%, hydrogen permeation decreases both at the corrosion potential and under conditions of anodic and cathodic polarization of the steel electrode. The inhibiting effect of emulgin is 96–97%.

ChemInform Abstract: Diversity Oriented Catalyst‐Free and Solvent‐Free One‐Pot MCR at Room Temperature: Rapid and Regioselective Convergent Approach to Highly Functionalized Dihydro‐4H‐thiopyrans.

Abstract Highly convergent and regioselective approach to hitherto unreported and synthetically demanding 6-cycloamino-2-(methyl/benzyl)sulfanyl-3-(aroyl/hetaroyl/alkanoyl)-4-aryl-5,6-dihydro-4H-thiopyrans has been developed via one-pot three-component domino coupling of β-oxodithioesters, α,β-unsaturated aldehydes, and cyclic aliphatic secondary amines at room temperature under catalyst-free and solvent-free conditions. The attractive features of this strategy include mild conditions, short reaction time, high atom-economy, excellent yields, and efficacy of forming three new bonds (C–C, C–N and C–S) and one ring in a single stroke.

ChemInform Abstract: Direct N‐Cyclopropylation of Secondary Acyclic Amides Promoted by Copper.

AbstractThe N‐cyclopropylation of aromatic and aliphatic secondary amines (I), known as poor nucleophiles, is accomplished using a simple and inexpensive copper system.

Elucidation of Carbene Ambiphilicity Leading to the Discovery of Reversible Ammonia Activation

An N,N'-diamidocarbene (DAC) was found to activate a broad range of primary as well as secondary aliphatic and aromatic amines. The relative rates measured for the insertion of the DAC into the primary amines were consistent with an electrophilic activation mechanism; in contrast, the DAC functioned as a nucleophile upon treatment with secondary aryl amines. Collectively, these results constituted the first ambiphilic process for an isolable carbene. By comparison, an analogous diaminocarbene was found to serve exclusively as a nucleophile under similar conditions and led to the discovery of the first organic reagent to reversibly activate ammonia.

Synthesis and gelation property of amino acids-based dendronised oligomers

The first- and second-generation dendrons constructed from alanine and aspartic acids were synthesised and further modified with a polymerisable acrylamide group at the focal point (MG1 and MG2). The corresponding dendronised oligomers were obtained by polymerisation, and then hydrolysed to afford them with multi-carboxyl groups on the periphery of branched side chains (PG1-COOH and PG2-COOH). The structures of the oligomers were characterised by 1H NMR, Fourier transform infrared and gel permeation chromatograph, and their gelation behaviour was examined. It was found that PG1-COOH and PG2-COOH could form two-component gels, especially, PG1-COOH showed better gelation property. For example, it could gel with aliphatic primary or secondary amines in dimethylformamide and with melamine in acidic aqueous solution. Transmission electron microscopy and atomic force microscopy images showed that the gelators self-assembled into the fibrous networks.

Synthesis of Some Novel α-Cyanoketene-N,S-acetals Derived from Secondary Aliphatic Amines and Their Use in Pyrazole Synthesis

New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence of triethylamine, under reflux in ethanol, for 1–16 h, depending on the amine used. Five N-methylalkyl amines and pyrrolidine yielded exclusively mono-substituted N,S-acetals 2(a–f) in good yields. On the other hand, N-ethylbenzylamine gave a mixture of monosubstituted products including N,S-acetal 2g in 35% yield and the unexpected product ethyl 3-[benzyl(ethyl)amino]-2-cyanoacrylate 3g in 50% yield. N-Ethylcyclohexylamine and N-ethylbutylamine did not produce N,S-acetals and gave only the unexpected products ethyl 2-cyano-3-[cyclohexyl(ethyl)amino]acrylate 3h and ethyl 3-[butyl(ethyl)amino]-2-cyanoacrylate 3i in good yields. The α-cyanoketene-N,S-acetals 2(a–f), 2j, and 2k underwent cyclization with the binucleophile hydrazine in ethanol under reflux to afford substituted pyrazoles 4(a–f), 4j, and 4k in good yields. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]

The vaporization enthalpy and vapor pressure of S (+)-methamphetamine at T = 298.15 K by correlation gas chromatography

The vaporization enthalpy and vapor pressure of S (+)-methamphetamine is evaluated by correlation-gas chromatography. A vaporization enthalpy of (58.7±4.3)kJ·mol−1 and a vapor pressure, p=(38±9)Pa has been obtained using a variety of secondary aliphatic amines as standards. In addition, equations describing the vapor pressure temperature dependence are provided for standards and S (+)-methamphetamine covering the temperature range from T=298.15K to the boiling temperature. Boiling temperatures are reproduced within an interval of 8K or less.

Parallel synthesis of 7-heteroaryl-pyrazolo[1,5-a]pyrimidine-3-carboxamides

A simple and practical four-step protocol for the parallel synthesis of 7-heteroaryl-pyrazolo[1,5-[Formula: see text]]pyrimidine-3-carboxamides was developed. The synthesis starts with transformation of commercially available 2-acetylpyridine and acetylpyrazine with [Formula: see text] [Formula: see text]-dimethylformamide dimethylacetal into the corresponding [Formula: see text]-3-(dimethylamino)-1-(heteroaryl)prop-2-en-1-ones followed by cyclisation with methyl 5-amino-1[Formula: see text]-pyrazole-4-carboxylate to give methyl 7-heteroarylpyrazolo[1,5-[Formula: see text]]pyrimidine-3-carboxylates. Hydrolysis of the ester group and subsequent amidation of the so formed carboxylic acids with 12 primary and secondary aliphatic amines furnished a library of 24 title compounds in good overall yields and purity.

The Tandem Mannich–Electrophilic Amination Reaction: a Versatile Platform for Fluorescent Probing and Labeling

Tandem fluorogenic reaction: A new platform for the direct, selective and sensitive detection of formaldehyde and/or secondary aliphatic amines, based on a tandem Mannich-electrophilic amination reaction, is described. Biological applications of hydrophilic, water-soluble fluorescent 2,2-dialkyl-2,3-dihydro-[1,2,4]triazolo[4,3-a]pyridin-2-ium-8-carboxylates (Safarinium P probes) are exemplified by labeling of the amine-containing Ac-AKF-NH2 peptide and Bacillus subtilis spores in aqueous solution.