Reaction Of Diamines Research Articles

One-pot sequential synthesis of fused and non-fused poly-substituted dihydropyridine derivatives under catalyst-free conditions

A one-pot, sequential, three-component procedure is reported for the synthesis of poly-substituted dihydropyridines via the condensation reaction of diamines or aminophenoles, 1,1-bismethylmethio-2-nitroethylene and α,β-unsaturated aromatic ketones in acetonitrile under reflux conditions. A range of fused and non-fused poly-substituted dihydropyridines were prepared in good to high yields with short reaction times.

PRODUCTION OF CARBON DIOXIDE CORROSION INHIBITORS OF STEEL FROM DIAMINES AND TALL OIL FATTY ACIDS

Substituted imidazolines are one of the most common and effective surface-acting metal corrosion inhibitors. The main tasks of today are to reduce their cost and increase their hydrolytic stability, which is achieved through a targeted choice of the nature and structure of long-chain carboxylic acids in the synthesis of imidazolines. Another way to reduce the cost of producing corrosion inhibitors based on aliphatic ethylenediamines is to use imidazoline precursors – amidoamines and ammonium salts - to protect against corrosion, the production of which is much less energy-consuming.The synthesis of active substances of carbon steel corrosion inhibitors in the reaction of diamines with fatty acids of tall oil was carried out. It is shown that depending on the temperature of the reaction and the introduction of the catalyst – polycationite CU-2-8 - it is possible to selectively obtain derivatives of imidazolines, amidoamines, and ammonium salts, which are capable of inhibiting carbon dioxide corrosion of steel in mineralized water at 60 °C with a degree of protection from 85 % to 91 %. It is noted that the protective effect of amidoamines and ammonium salts is practically not inferior to the action of imidazolines.

Visible Light-Mediated Heterodifunctionalization of Alkynylazobenzenes for 2H-Indazole Synthesis.

We disclose the heterodifunctionalization of alkynylazobenzenes promoted exclusively by visible light in the absence of any transition metal and/or photocatalyst. This reaction features excellent regioselectivity on a broad variety of substrates with perfect atom economy. Alcohols, carboxylic acids, thiols, amides, heterocycles, and even water are suitable substrates for the promotion of the oxyamination, sulfenoamination, and diamination reactions. In this manner, biologically active indazole scaffolds can be rapidly assembled from alkyne feedstocks.

Photocatalytic Unsymmetrical Diamination of Styrenes, Indoles, and Benzofurans Facilitated by Benzotriazolyl and Iminyl Radicals.

Utilizing energy transfer catalysis, this research employed the bifunctional reagents benzotriazole carboxylic acid oxime esters to simultaneously generate benzotriazole and imine radicals. The synthesis of two distinct C-N bonds in a single conversion is showcased through radical addition and radical-radical cross-coupling processes between benzotriazole carboxylic acid oxime ester and olefins. This process facilitates the intermolecular two-component unsymmetrical diamination reaction of olefins. Using this approach, more than 40 benzotriazole-containing molecules were successfully synthesized using styrene, indole, and benzofuran as acceptors, with yields ranging from moderate to excellent.

Visible light-mediated copper catalyzed regioselective diamination of terminal alkynes at room temperature: a facile synthesis of substituted imidazo[1,2-α]pyridines

We have developed a protocol for the regioselective synthesis of substituted imidazo[1,2-α]pyridines at room temperature using low-energy visible light, inexpensive CuCl as a catalyst, readily available starting materials, mild reaction conditions, and O2 as a green oxidant.

Green synthesis of tryptanthrin appended 4-spiropiperidines and their anti-bacterial evaluation

Synthesis of 14 tryptanthrin appended 4-spiropiperidines and their detailed antibacterial evaluation are described. The synthesis was achieved by a green route employing ammonium acetate as a catalyst in the three-component reaction of tryptanthrin, malononitrile and m-phenylene diamine. The in vitro antibacterial activities of compounds were evaluated against ESKAPE pathogens and against clinical multidrug-resistant MRSA and VRSA isolates, from which the bromo- and chloro-substituted spiropiperidines 4b and 4c (MIC 4 μg/mL) was found to be most potent against S. aureus ATCC 29213 and 4c exhibited good selectivity index.

Synthesis,Characterization and Antimicrobial Evolution of New Bi-α-amino Nitrile Compounds

This project is regarding the synthesis of new bi-α-amino nitrile compounds derived from the reaction of di-amine , aldehyde (vanillin oro-vanillin ),and KCN in glacial acetic acid as a solvent . The three components-one pot reaction produced (2,2'-(1,2-phenylenebis(azanediyl))bis(2-(4-hydroxy-3-methoxyphenyl)acetonitrile) (I) and(2,2'-(1,2-phenylenebis(azanediyl))bis(2-(2-hydroxy-3-methoxyphenyl)acetonitrile) (II)considering the formation of bi-imine compounds as intermediate. α-amino nitrile compounds (I and II) were characterized using infrared spectroscopy and mass spectroscopy. The prepared compounds were screened for their anti-microbialactivity. The bacteria are Gram positive (Staphylococcus aurous) and Gram negative (Escherichia coli) in vitro, the results were promising; due to the large inhibition zones.

Development of vanillin-based crosslinking agent with phase-locked dynamic imine bonds for shape-memory polyurethanes

Scientists have gained so much attention due to one of polyurethane's tuneable and unique characteristics, i.e., the shape-memory effect. But, the simplistic fabrication of such materials persists a challenging work. In the current work, we report the synthesis and detailed characterization of shape-memory polyurethane obtained by incorporating lower concentrations of imine bonds, which readily undergo phase-locking systems beneficial for microphase separation. A symmetric imine moiety (DIM) was designed through the simple Schiff-base reaction of naphthalene diamine and vanillin. The tensile strength of the films reached up to 30 MPa with an %elongation of 87% by tuning the hard segment content and the concentration of imine bonds. Also, in the meantime, the films showed excellent shape memory effect, where the shape could recover its original form within 2 s at the highest loading of DIM. The remarkable balance between the mechanical properties and the shape memory effect could be associated with the two main factors. Firstly, incorporating symmetrical and rigid CN along with the naphthalene promoted the microphase separation and smoothened the orientation of the chain segments at the strain-induced crystallization at lower temperatures. Secondly, the phase locking occurred at lowered temperatures due to dynamic imine exchange reaction and H-bonding. The phase recovery started, and chains settled at their original positions once the temperature was elevated.

Green synthesis and theoretical study of new 1,3,4‐oxadiazoles: Application of Cu/Fe3O4@MWCNT magnetic nanocomposites

Cu/Fe3O4@MWCNT magnetic nanocomposites (MNCs) as an effective catalyst was promoted producing of novel derivatives of 1,3,4‐oxadiazols in high yields. These new compounds were synthesized by using multicomponent reaction of ninhydrins, diamines or hydroxyamines, ester of acetylene with electron deficient, α‐haloketones, hydrazoyl chloride, and synthesized nanocatalyst in aqueous media. It should be mentioned that the high performance of nanocatalyat was synthesized by using water extract of Petasits hybridus leaves, which was utilized in these reactions for many times to confirm the reusability of nanocatalyst. The antioxidant property of new synthesized 1,3,4‐oxadiazols is owing to having NH group which was evaluated by two procedures named diphenyl‐picrylhydrazine (DPPH) radical trapping and Ferric ions (Fe3+) reducing potential (FRAP) experiment. Also, the antimicrobial activity of new generated 1,3,4‐oxadiazols was evaluated by disk distribution process utilizing two kinds of Gram‐negative bacteria and Gram‐positive bacteria, proving bacterial growth was stopped by using of these compounds. This employed procedure for preparation of 1,3,4‐oxadiazols derivatives conveys benefits including reaction with low time, products with high yields, and possibility of separating catalyst and products using an easy procedure.

Iridium(III)-Catalyzed Regioselective B(4)-H Amination of o-Carboranes with Sufilimines.

Iridium(III)-catalyzed regioselective B(4)-H amination is developed from the reaction of o-carborane acids with sulfilimines without any oxidants under mild conditions, which leads to a wide range of B(4)-H aminated o-carboranes in good yields with a broad substrate scope. Moreover, the selective B(3,6)-diamination reaction of the o-carborane acid was achieved. The present reaction is attractive from a practical point of view because dibenzothiophene is quantitatively recovered and reused.

Copolymers of poly(aryl ether ketone)/poly(ether ether amide) containing different numbers of methylene in the main chain: Synthesis and properties

Abstract“One‐step polymerization method” was used to improve the thermal property of semi‐aromatic poly(ether ether amide) (PEEA). Firstly, a series of difluorobenzamide monomers containing different numbers of methylene were synthesized by the reaction of diamine and 4‐fluorobenzoic chloride using a facile interfacial reaction method. Then, these syntheses were conducted to react with bisphenol AP and 4,4′‐difluorobenzophenon to synthesize the novel poly(aryl ether ketone)/semi‐aromatic poly(ether ether amide) copolymers (PAEK/PEEA) with different chain lengths in the chain through nucleophilic substitution by a one‐step method. The obtained copolymers were amorphous with inherent viscosities of 0.373–0.433 dLg−1. They were found to have high glass transition temperatures (Tg) of 160–191°C, good thermal stability with 5% weight‐loss temperature (T5%) of 409–437°C. The tensile strengths of the copolymers were 65.0–75.8 MPa. The storage modulus were over 0.9 GPa at 120°C. At room temperature, the copolymers were soluble in NMP, slightly soluble in DMF, CH2Cl2, CH3Cl, indicating that the synthesized copolymers could be processed by solution method. The results of optical performance showed that the copolymers had good optical transmittance with the optical transmittance of 75.7%–86.1% at 450 nm. They have the potential to be applied as the novel heat‐resistance optical films as the novel copolymers.

Cobalt(III)‐Catalyzed Aerobic Diamination of α‐Alkyl Styrenes with Anilines

AbstractA commercially available cobalt complex Cp*CoIII(CO)I2 has been found to effectively catalyze the diamination of α‐alkyl styrenes with anilines under a mild reaction condition, using dioxygen as the oxidant. This reaction features a reasonably good substrate scope of amines and a good functional group tolerance. Preliminary mechanistic studies have shown that Cp*CoIII(CO)I2 alone can promote the diamination reaction.

Synthesis of 3‐Aminopiperidines via I(III)‐Mediated Olefin Diamination with (Hetero)aryl Nucleophiles

Abstract3‐Aminopiperidines are a valuable motif present in small molecule pharmaceuticals and bioactive natural products. Synthesis of these moieties via olefin diamination would be an attractive approach, however significant challenges remain with regards to both regioselectivity and exogenous nucleophile scope. Herein, we report a metal‐free olefin diamination via a “heterocyclic group transfer“ (HGT) reaction of I(III) N‐HVI reagents, giving rise to 3‐aminopiperidines with high selectivity. The HGT strategy leverages heteroarenes as oxidatively masked amine nucleophiles, giving rise to (hetero)arylonium salt products which are isolated via simple trituration and provide a versatile handle for downstream diversification. This represents only the second 6‐endo selective I(III)‐mediated diamination reaction and mechanistic studies indicate ring opening of an intermediate aziridinium ion is responsible for the 6‐endo selectivity.

Pyrolysis and thermal degradation studies of non-isocyanate polyurethanes modified by polyhedral oligomeric silsesquioxanes

This work reports on the thermal properties of non-isocyanate polyurethanes (NIPUs) obtained via the polyaddition reaction of polyether diamine with five membered tri(cyclic carbonate) by using a prepolymerization method. The non-isocyanate polyurethanes were further chemically modified by trifunctional polyhedral oligomeric silsesquioxane (POSS) - triglycidylisobutyl POSS (3epPOSS), resulting in hybrid composite materials containing 5 to 15 wt% POSS. Thermal properties of the obtained materials were studied by various methods, such as Thermogravimetric analysis (TGA), Pyrolysis with gas chromatography and mass spectrometry (Py-GC/MS), and Microscale Combustion Calorimetry (MCC), and were later discussed in dependence of their composition and structure assessed by Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques. FTIR spectra confirm the successful synthesis of NIPUs and their hybrids with POSS. The results of XRD and SEM revealed homogeneous distribution of silsesquioxane in the bulk of the NIPU matrix. Depending on the POSS concentration in the PU hybrids, various self-assembling structures were formed. TGA analysis indicated a two- and three-step degradation process of NIPU materials in inert and oxidative atmospheres, respectively. Significantly higher degradation temperatures and a remarkably reduced degradation rate for composite materials compared to unmodified NIPU matrix were observed during the second degradation step under an oxidative atmosphere. Based on the overall stabilization effect (OSE), hybrids containing 10 and 15 wt% of 3epPOSS were more thermally stable than the unmodified NIPU matrix. Py-GC/MS demonstrated that the products of NIPU thermal decomposition originate from hydroxyurethane moieties, main substrate core structures, and others, such as catalysts. Incorporation of 3epPOSS into the NIPU matrix decreases its flammability, as evidenced by the results of the MCC, with a nearly 20 % reduction effect noted for the composite with of 15 wt% of POSS, compared to the unmodified NIPU matrix. Importantly, chemical modification of NIPU by POSS caused a reduction of the heat of combustion in the final stage of degradation by ca. 30 %.

Room-Temperature Self-Healing Polyurea with High Puncture and Impact Resistances

Polyureas are widely used as protective materials because they have good mechanical strength, toughness, and strain-rate-dependent behavior. However, the fast reaction between −NCO and the −NH2 component results in gelation in seconds, limiting their performance regulation and applications. In this study, we report a novel strategy to fabricate one-component polyurea with room-temperature self-healing, puncture resistance, and impact resistance. First, a latent curing agent was synthesized via the Schiff base reaction of an aliphatic diamine with isobutyraldehyde. Then, they were mixed directly with isocyanate. Such a mixture was uncured in storage without moisture, but it was cured once in contact with moisture in the application. So, it was called one-component polyurea. The polyurea exhibits room-temperature self-healing properties with a healing efficiency of up to 98%. It has puncture displacement as high as 15.1 cm by sharp objects. The polyurea also exhibits excellent impact resistance and dissipative energy capacity because it possesses strain-rate-dependent behavior. The polyurea can be integrated into Kevlar fabrics to form a flexible puncture-resistant composite and combined with carbon nanotubes to form flexible and wearable strain sensors. It is expected to find applications in intelligent soft materials, soft body armor, wearable flexible sensors, and other fields.

Site-Selective Oxidative Coupling Reaction of Diamines toward Aminoazo Compounds

A selective oxidative coupling reaction of a diamine containing both C- and N-NH2 was achieved using acidic potassium permanganate as the coupling reagent. The reaction conditions were optimized, and the reaction selectivity was illustrated by quantum calculations. Furthermore, the azo-coupled product was derivatized to four nitroamine energetic materials with excellent detonation performances.

Synthesis and Characterization of new Mannich Bases for Pyrazole containing Benimidazole Ring

This research includes synthesis of new derivatives of benzimidazole , the compound (A1*) prepared by reaction of o-phenylene diamine with carbon disulfide in alcoholic potassium hydroxide. Then the compound (A1*) was reaction with ethyl chloroacetate and potassium hydroxide to give ester (A2*). Then preparation of hydrazide (A3*) by the reaction of (A2*) with hydrazine hydrate (80%). Then we used the hydrazide (A3*) to prepare pyrazole (A4), then preparation of mannich basses by reaction of compound (A4) with different primary aromatic amines and formaldehyde

Anchored ferrocene based heterogeneous electrocatalyst for the synthesis of benzimidazoles

A facile and sustainable electrochemical synthetic strategy for phenyl benzimidazoles has been developed using a ferrocene-based electrocatalyst anchored on Toray carbon paper (TCP) coated with conducting polymeric film. The developed electrode was used for the electrochemical dehydrogenative cyclization reaction of o-phenylene diamine and benzaldehyde using lithium perchlorate/acetonitrile as electrolyte. The surface characteristic properties of the developed electrode were characterized by FESEM, Optical profilometer and X-ray photoelectron spectroscopy. Electron transfer mechanism of the anchored ferrocene-based electrocatalyst was thoroughly studied. To determine the efficacy of the catalyst, the electron transfer coefficient (0.5) and apparent rate constant 41.4 s−1 were determined. The cyclic voltammetry studies reveal that the electrochemical oxidation peak for the synthesis of benzimidazole occurs at 0.48 V. The formation of the product was confirmed by Gas chromatography and Nuclear Magnetic Resonance spectroscopy. A comparison chart is presented for the green metrics and sustainability of the present strategy with other electrochemical approach.

β-cyclodextrin: Green catalyst for the efficient and expeditious synthesis of benzodiazepines under aqueous conditions

An efficient and facile green method for synthesis of four substituted 1,5-benzodiazepine derivatives via a three-component reaction of dimedone, o-phenyl diamine, and various substituted aldehydes are designed using β-cyclodextrin as a catalyst at reflux condition. The current one-pot multicomponent methodology offers several advantages, such as good to excellent yields, simplicity in experimental procedure, easy work-up procedure, shorter reaction time, energy-conserving, broad substrate scope, avoidance of hazardous chemicals, etc. Further, the catalyst was recovered and recycled 4–5 times without compromising the yield of the final product.

Synthesis and Molecular Docking Studies of New Series of Bis-Schiff Bases Thiadiazoles Derived From Disulfides and Thioethers with Potent Antibacterial Properties

Two new series of various heterocyclic bis-Schiff bases of Thiadiazoles disulfides and thioethers are synthesized. The first series was the synthesis of bis-Schiff of thiadiazole disulfides (4a-h) synthesized from their corresponding Schiff bases after oxidation by hydrogen peroxide. The second series was the synthesis of bis-Schiff base thiadiazole thioethers (7a-h). It was obtained from the reaction of bis-thiadiazole diamine (6) with different aldehyde. The diamine (6) was generated by reacting thiadiazole with dibromoethane in dimethylformamide and triethylamine as a catalyst. All of the synthesized compounds were analyzed by using FT-IR, 1H-NMR, 13C-NMR, and C-APT techniques. The synthesized compounds were screened against two gram-positive bacteria (Staphylococcus and streptococcus), and two strains of gram-negative (E. coli and klebsiella) in comparison to two standard strong antibiotic drugs (ciprofloxacin and vancomycin). Generally, all the synthesized compounds showed highly antibacterial properties, particularly, compounds (4b,4f, and 7b) which observed potent anti-bacterial properties against both gram- (positive, negative) bacteria were even higher than the standard drugs. Lastly, molecular docking studies were also applied to find the binding affinity and active sides of the products with the target proteins.