Reaction Of Amines Research Articles

Sustainable Synthesis of Indole-Substituted Densely Functionalized Pyrrole.

A novel chromatography- and catalyst-free methodology has been developed for the synthesis of poly substituted pyrrole in good yields via a multicomponent reaction of arylglyoxal, 1,3-dicarbonyl, indole, and aromatic amine. This strategy provides various advantages such as simple experimental and workup procedures, mild reaction conditions, no added catalyst, use of green solvent, and simple purification procedure of pure product without using column chromatography. This green method offers a simple and highly effective strategy to synthesize a wide range of indole-pyrrole conjugates in a one-pot operation.

Effect of Protein Surface Hydrophobicity and Surface Amines on Soy Adhesive Strength.

Soy is considered one of the most promising natural materials for manufacturing wood adhesives due to its low cost, high protein content, and ready availability. However, more cost-effective ways of improving its wet shear strength are needed to achieve wider market acceptance. Protein adhesive wet strength depends on the use of (typically expensive) crosslinking additives as well as the processing/denaturation of the protein. It has been commonly stated in the literature that protein denaturation leads to higher bond strength by activating the surface and exposing the reactive groups. Therefore, we investigated how differences in surface reactive groups (surface hydrophobicity and reactive amine groups) brought on with different denaturation treatments relate to bonding performance. Fourteen soy protein isolates (SPIs) with different denaturation histories were investigated. Characterization of the SPIs included surface hydrophobicity, surface amine content, extent of protein hydrolysis, and bond strength (wet and dry, with and without polyamidoamine epichlorohydrin (PAE) crosslinking agent) by ASTM D7998. The molecular weight patterns showed that proteins denatured by extensive hydrolysis had very low bond strengths. Adding the crosslinker, PAE, improved all the shear strength values. We found that the number of water-accessible reactive amine groups on protein surfaces had no impact on the adhesive strength, even with the amine-reactive crosslinker, PAE. Conversely, increased surface hydrophobicity was beneficial to adhesive strength in all cases, though this correlation was only statistically significant for wet strength without PAE. While, in general, denatured proteins are typically thought to form better bonds than native state proteins, this work suggests that it matters how proteins are denatured, and what surfaces become exposed. Denaturation by hydrolysis did not improve bond strength, and extensive hydrolysis seemed highly detrimental. Moreover, exposing hydrophobic surface groups was beneficial, but exposing covalent bond-forming reactive amine groups was not.

Noble metal free double helix binuclear Cu(I) complex as catalyst for carboxylative cyclization of propargylamines with atmospheric carbon dioxide toward oxazolidinones synthesis under mild conditions

The application of economically abundant, renewable and C1-feedstock, carbon dioxide into organically important compounds is considered as the hot topic in modern aspects. In this prospective, a binuclear double helix copper (I) complex (1) was synthesized through insitu reaction between quinolone-2-carbaldehyde and succino-hydrazide with copper (II) nitrate hexahydrate. Single crystal X-ray analysis of complex 1, clearly explained that both tetra co-ordinated Cu(I) ions are in tetrahedral geometric environment, having suprmolecular network arrangement via weak interaction of H-bonding, π…π stacking and CH…π stacking. The complex 1 was found to be effectively active catalyst in carboxylative cyclization reaction of propargylic amines with carbon dioxide towards oxazolidinones synthesis under atmospheric pressure and mild reaction conditions. Due to the initiation of side reaction by –NH2 group of primary propargyliamines, which reduces the yield percentage of respective oxazolidinones as a result the carboxylative cyclization reaction of primary propargylic amines, was rarely developed. In this work both primary and secondary propargylamines smoothly undergoes through this catalytic reaction and produced high percentage of desired oxazolidinones product. Again neat condition for this catalytic reaction makes the methodology more environmentally benign and sustainable. The complex 1 showed luminescent property. Moreover DFT methods were utilized in order to explain the probable mechanistic pathway of carboxylative cyclization reaction.

Metal‐Free Synthesis of 2‐Aminobenzothiazoles via I2‐Catalyzed Tandem Cyclization Reaction of Amines and Carbon Disulfide

Comprehensive SummaryA convenient approach for the construction of 2‐aminobenzothiazoles via I2‐catalyzed tandem cyclization reaction of amines and carbon disulfide has been developed. The present approach starts from simple and readily available starting materials, affording a series of 2‐aminobenzothiazoles in up to 89% yields under metal‐free conditions. In this work, C—H/N—H functionalization was achieved and multiple C‐hetero bonds were successfully constructed in one pot.

Iterative real-time optimization of a reductive amination process in a thermomorphic multiphase system

In this paper, we discuss the optimization of the operation of a reductive amination (RA) reaction process in a miniplant without an accurate process model using iterative real-time optimization (RTO). The rhodium-catalyzed RA of undecanal with diethylamine produces a tertiary amine from a long-chain aldehyde and is performed in a thermomorphic multiphase system (TMS) to recover and reuse the expensive catalyst efficiently. An iterative RTO method called modifier adaptation with quadratic approximation (MAWQA) is used in combination with guaranteed model adequacy (GMA) to drive the RA process to its optimum iteratively. MAWQA utilizes online measurements to overcome model deficiencies. GMA ensures that the model used in MAWQA satisfies the model adequacy conditions. The optimal operating conditions of the RA process in the miniplant were identified during an experimental run of the plant, thereby validating the applicability and efficiency of MAWQA with GMA. The results illustrate the benefits of process optimization using iterative RTO methods without accurate process models.

Insights into the role of the H-abstraction reaction kinetics of amines in understanding their degeneration fates under atmospheric and combustion conditions.

Amines, a class of prototypical volatile organic compounds, have garnered considerable interest within the context of atmospheric and combustion chemistry due to their substantial contributions to the formation of hazardous pollutants in the atmosphere. In the current energy landscape, the implementation of carbon-neutral energy and strategic initiatives leads to generation of new amine sources that cannot be overlooked in terms of the emission scale. To reduce the emission level of amines from their sources and mitigate their impact on the formation of harmful substances, a comprehensive understanding of the fundamental reaction kinetics during the degeneration process of amines is imperative. This perspective article first presents an overview of both traditional amine sources and emerging amine sources within the context of carbon peaking and carbon neutrality and then highlights the importance of H-abstraction reactions in understanding the atmospheric and combustion chemistry of amines from the perspective of reaction kinetics. Subsequently, the current experimental and theoretical techniques for investigating the H-abstraction reactions of amines are introduced, and a concise summary of research endeavors made in this field over the past few decades is provided. In order to provide accurate kinetic parameters of the H-abstraction reactions of amines, advanced kinetic calculations are performed using the multi-path canonical variational theory combined with the small-curvature tunneling and specific-reaction parameter methods. By comparing with the literature data, current kinetic calculations are comprehensively evaluated, and these validated data are valuable for the development of the reaction mechanism of amines.

A rhodium(II)/rhodium(III) redox couple for C-H bond amination with alkylazides: a rhodium(III)-nitrenoid intermediate with a tetradentate [14]-macrocyclic ligand.

The catalytic activity of a rhodium(II) dimer complex, [RhII(TMAA)]2 (TMAA = tetramethyltetraaza[14]annulene), in C-H amination reactions with organic azides is explored. Organic azides (N3-R) with an electron-withdrawing group such as a sulfonyl group (trisylazide; R = S(O)2iPr3C6H2 (Trs)) and a simple alkyl group (R = (CH2)4Ph, (CH2)2OCH2Ph, CH2Ph, or C6H4NO2) are employed in intra- and intermolecular C-H bond amination reactions. The spectroscopic analysis using ESI-mass and EPR spectroscopy techniques on the reaction intermediate generated from [RhII(TMAA)]2 and N3-R reveals that a rhodium(III)-nitrenoid species is an active oxidant in the C-H bond amination reaction. DFT calculations suggest that the species can feature a radical localised nitrogen atom. The DFT calculation studies also indicate that the amination reaction involves hydrogen atom abstraction from the organic substrate R'-H by the NR moiety of 2N˙R and successive rebound of the generated organic radical intermediate R'˙ to [RhIII(NH-R)(TMAA)], giving [RhII(TMAA)] and R'-NH-R (amination product).

Catalytic atroposelective electrophilic amination of diaryl anilines and diaryl phenols for the synthesis of axially chiral diaryl compounds

A CPA-catalyzed atroposelective electrophilic amination reaction has been developed, which provides access to a series of axially chiral diaryl compounds through the desymmetric amination reactions of diaryl anilines/phenols with azodiformates.

Highly enantioselective allylic amination reaction through aerobic oxidative organo–organo dual catalytic system

An NHC/chiral tertiary amine dual catalytic system for the aerobic oxidation/allylic amination reaction has been developed. The combination of NHC with organo-catalysts especially with tertiary amine catalysts remains an underexplored area.

Ambient catalyst-free oxidation reactions of aromatic amines using water radical cations.

Water radical cations play a pivotal role in various scientific and industrial fields due to their unique reactivity and capacity to drive complex chemical transformations. Here we explored the formation of quaternary ammonium cations through the direct oxidation reaction of aromatic amines, facilitated by water radical cations within water microdroplets. This process was monitored via in situ mass spectrometry and occurs under ambient conditions, negating the need for traditional chemical catalysts or oxidants and achieving an impressive yield of approximately 80%. Additionally, we employed a multi-channel spray system and enhanced both the reactant concentration and flow rate, thereby enabling gram-scale synthesis. These findings not only demonstrate the effectiveness and eco-friendliness of microdroplet chemistry but also provide a new understanding of heterogeneous ˙OH generation channels, thereby boosting the synthetic efficiency and sustainability of chemical processes.

A novel porphyrin MOF catalyst for efficient conversion of CO2 with propargyl amines.

The capture and conversion of carbon dioxide (CO2) into valuable chemical products under mild conditions is an important and challenging approach for contemporary industry. Carboxylic acid ligands are widely used in the development of functionalized metal organic framework materials due to their excellent stability. Herein, a novel mixed-metal organic framework Cu-TCPP(Fe) was assembled from iron-(Fe)-porphyrin ligands, which can efficiently catalyze the reaction of propargylic amines and CO2 to synthesize 2-oxazolidinones.

Directed nucleophilic aromatic substitution reaction.

In this study, we discovered a directed nucleophilic aromatic substitution reaction, "directed SNAr (dSNAr)," in the reaction of ortho-iodobezamides and amine in the presence of pyridine. The reaction proceeded ortho-specifically and did not require a strong electron-withdrawing group on the arene substrate. Most reactions proceeded at room temperature in the presence of Py, and a wide range of amine nucleophiles can be applied. Furthermore, the reactions with benzamide substituted with multiple halogens were found to be 100% ortho-selective.

A review on vegetable oil-based non isocyanate polyurethane: towards a greener and sustainable production route.

The transition from conventional polyurethane (PU) to non isocyanate polyurethane (NIPU) is driven mainly by safety concerns, environmental considerations, and sustainability issues associated with the current PU technology. NIPU has emerged as a promising alternative, addressing limitations related to traditional PU production. There has been increasing interest in bio-based NIPU aligning with the aspiration for green materials and processes. One important biomass resource for the development of bio-based NIPU is vegetable oil, an abundant, renewable, and relatively low cost feedstock. As such, this review aims to provide insight into the progression of NIPU derived from vegetable oils. This article highlights the synthetic and green approach to NIPU production, emphasizing the method involving the polyaddition reaction of cyclic carbonates and amines. The review includes case studies on vegetable oil-based NIPU and perspectives on their properties. Further, discussions on the potential applications and commercial importance of PU and NIPU are included. Finally, we offer perspectives on possible research directions and the future prospects of NIPU, contributing to the ongoing evolution of PU technology.

6-Aryl-4-cycloamino-1,3,5-triazine-2-amines: synthesis, antileukemic activity, and 3D-QSAR modelling.

Despite significant progress in immunotherapy and chimeric antigen receptor T cell therapy of leukemia, chemotherapy is the major treatment option for the disease. Therefore, the development of potent and safe drugs for standard and targeted chemotherapy of leukemia remains an important task for medicinal chemists. A library of 94 diverse 6-aryl-4-cycloamino-1,3,5-triazine-2-amines was prepared using a one-pot microwave-assisted protocol, which involves a three-component reaction of cyanoguanidine, aromatic aldehydes and cyclic amines, and subsequent dehydrogenative aromatization of the dihydrotriazine intermediates in the presence of alkali. The cytotoxic properties of prepared compounds were evaluated against the leukemic Jurkat T cell line and the selectivity of the 24 most active compounds was also assessed using a normal fibroblast MRC-5 cell line, indicating selective antiproliferative activity against leukemic cells. The structure-activity relationship was analysed, and the prepared 3D-QSAR model was found to predict the antileukemic activity of the compounds with reasonable accuracy. In the cell morphology study, both apoptosis and necrosis features were observed in Jurkat T cells after treatment with the most active compound.

Modular three-component synthesis of 6H-benzochromenone based blue luminogens under catalyst- and solvent-free conditions

Highly efficient synthesis of benzochromenone based blue luminogens via a three-component reaction of 2-hydroxychalcones, primary amines and β-ketoesters was demonstrated.

A mixed-valence CuI/CuII metal–organic framework for CO2 conversion

A CuI/CuII mixed-valence metal–organic framework with a rarely reported (3,4,4)-c network topology has been prepared. It can effectively catalyze the cyclization reaction of epoxides or propargyl amines with carbon dioxide.

Design, synthesis and characterization of new azoflavone derivatives through diazotisation - coupling reactions of aromatic amines (sulfanilic acid, 2-amino pyridine)

In this research, new azochalcone derivatives (6, 7) were synthesized by using three methods: the first one is diazotization - coupling method of different aromatic amines (sulfanilic acid, 2-aminopyridine) with chalcone (5), the second, aldol condensation method of azoaryl hydroxyacetophenone compounds with 4-dimethylamino benzaldehyde in presence of sodium hydroxide as a catalyst, the last one is method of aldol condensation of azoaryl hydroxyacetophenone compounds with 4-dimethylaminobenzaldehyde in presence of piperidine as an organic catalyst. The yield was the best by using the aldol condensation method with sodium hydroxide as a catalyst. New azoflavone derivatives (8, 9) with good yields (78-84 %) were also synthesized by performing cyclization reactions of azochalcone derivatives using iodine in dimethyl sulfoxide. The identity of the new compounds was determined using spectroscopic methods (FT-IR, 13C-NMR, 1H-NMR).

Metal-free efficient synthesis of aryl sulfonamides from N-hydroxy sulfonamide and amines.

A simple and novel approach has been developed for the synthesis of sulfonamides from N-hydroxy sulfonamide. Notably, the iodine-tert-butyl hydroperoxide (TBHP) system efficiently promoted the sulfonylation reactions of N-hydroxy sulfonamides and amines via the oxidative cleavage of an S-N bond. A variety of aryl sulfonamides were prepared in moderate to good yields using readily available starting materials and the biomass-derived 2-MeTHF solvent. The present method has the advantages of using metal-free reagents, an eco-friendly medium, cost-effective reagents, wide substrate scope, and mild conditions.

Synthesis of imines from the coupling reaction of alcohols and amines catalyzed by phosphine-free cobalt(II) complexes.

Phosphine-free, air stable cobalt(II) based complexes (1a and 1b) consisting of ligands L1H2 and L2H2 (L1H2 = N,N'-((1,2-phenylenebis(azaneylylidene))bis(methaneylylidene))diphenol and L2H2 = N,N'-bis(4-diethylaminosalicylidene)-4,5-dichloro-1,2-phenylenediamine) were synthesized and utilized as catalysts in the coupling reaction of alcohols with amines into imines following an acceptorless dehydrogenative pathway. The reactions were carried out in the presence of t-BuOK base with low catalyst loading (1 mol%) in an open atmosphere. The corresponding imines were isolated in moderate to excellent yields. The methodology was screened with different substituted alcohols and amines. The proposed mechanistic pathway of this reaction was ascertained through intermediate mass and 1H NMR analyses. Most of the previously reported 3d transition metal catalysts used in imine synthesis reactions have a phosphine ligand environment, and the reactions were performed under inert conditions. Herein we have developed a sustainable route for the synthesis of imines from the coupling reaction of alcohols with amines under aerial reaction conditions using phosphine-free air stable cobalt catalysts.

Lactic, Malic, Tartaric, Citric and Ascorbic Acid as Natural and Green Organocatalysts for Microwave-Induced Solvent-Free Synthesis of Enaminones

The enaminone framework is a versatile building block used in organic synthesis. Herein, a series of β-enaminones were synthesized in good to excellent yields from the reaction of various aliphatic and aromatic primary amines with 1,3-dicarbonyl compounds using common natural organic acids (lactic, malic, tartaric, citric and ascorbic acid) as green, eco-friendly and efficient catalysts under microwave irradiation and solvent-free conditions.