Search

The nanocomposites of polythiourethane (PTU) with Fe3O4 were fabricated via an isocyanate-free approach. The nanocomposites simultaneously had the reprocessing, shape memory and photothermal properties. First, a linear PTU carrying a plethora of thiol groups was synthesized via the ring opening polyaddition between a bicyclic trithiocarbonate and a poly (propylene oxide) diamine. In the meantime, the surfaces of Fe3O4 nanoparticles were functionalized with thiol groups. Second, the co-crosslinking between the linear PTU and the thiol-functionalized Fe3O4 was performed via the coupling of thiol radicals with a radical initiator. Notably, the nanocomposites of PTU with Fe3O4 were successfully obtained with the fine dispersion of Fe3O4 nanoparticle in PTU matrix. Compared to control PTU, the nanocomposites displayed the improved thermomechanical properties. More importantly, the nanocomposites had reprocessing properties. The dynamic exchange of disulfide bonds is responsible for the reprocessing behavior. Owing to the crosslinking with disulfide bonds, PTU had shape memory properties. Notably, the incorporation of Fe3O4 nanoparticles was capable of improving the shape memory properties. In addition, the nanocomposites displayed the photothermal properties with the incorporation of Fe3O4 nanoparticles. The photothermal conversion behavior can be utilized to trigger the shape recovery of the nanocomposites under near-infrared light irradiation and in a non-contact fashion. [ABSTRACT FROM AUTHOR]

It was shown that copolyimides based on adamantane-containing diamine and dianhydrides of 2,3,3′,4′-biphenyltetracarboxylic acid (a-BPDA) and 5,5′-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)bis(2-benzofuran-1,3-dione) (6FDA) are characterized by good thermal-oxidative properties (T5% = 465–485 °C) and a high optical transparency (T400 = 60–80%) in comparison with copolyimides based on the same dianhydrides and 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine (TFBA), containing bulky trifluoromethyl fragments (T400 = 38–67%). [ABSTRACT FROM AUTHOR]

New oligoether diamines were synthesized via the step of obtaining oligoether diacrylates, followed by their subsequent reaction with 3-aminomethyl-3,5,5-trimethylcyclohexylamine. A series of urethane-containing elastomers based on them was obtained. The polymers were evaluated by differential scanning calorimetry, and their deformation and strength characteristics were also estimated. It was demonstrated that a low glass transition temperature is characteristic of all the polymers. [ABSTRACT FROM AUTHOR]

Tetrakis-benzimidazoles draw attention with their structural similarities to ethylenediaminetetraacetic acid (EDTA) which is a medication used in the management and treatment of heavy metal toxicity, as well as having many different derivatives. In addition to the tetradentate feature due to the donor characteristic of the C=N nitrogen atom in each benzimidazole unit, there are also tetrakis-benzimidazole derivatives that show ligand properties up to octadentate through donor atoms such as N and O in the bridge units. The applications of tetrakis-benzimidazole derivatives and various metal complexes in many fields such as corrosion inhibitor, catalyst, enzyme inhibitor, superoxide dismutase, catalase activity, superoxide oxidase, DNA affinity, determination of H2O2, were investigated. In this study, a comprehensive review was conducted on N,N,N',N'-tetrakis(1H-benzimidazol-2-ylmethyl)ethane-1,2-diamine (EDTB), a hexadentate tetrakis-benzimidazole derivative. Synthesis routes, properties, various complexes of EDTB and its derivatives, their structural features and application areas have been reviewed and compiled in order to be useful for researchers who will work in this field. [ABSTRACT FROM AUTHOR]

1,3-bis((1H-1,2,4-triazol-1-yl)methyl)hexahydropyrimidine was readily prepared by cyclocondensation of propane-1,3-diamine with a mixture of (1H-1,2,4-triazol-1-yl)methanol and formaldehyde. The 1H- and 13C-NMR spectroscopic data of this ligand have been fully assigned and are consistent with the molecular structure. The crystalline structure of the compound was fully determined by single crystal X-ray diffraction at 150 K and at room temperature, together with the isobaric thermal expansion. Finally, during the first heating, DSC measurements showed no phase transition up to the melting temperature at 385.1 K (111.9 °C). [ABSTRACT FROM AUTHOR]

The current landscape of chiral covalent organic frameworks (COFs) predominantly centered on constructing asymmetric molecular-scale chirality, often introducing an inherent contradiction to the COF symmetry and limiting diversity. Herein, we overcome these challenges by achieving chiral transfer between one-dimensional (1D) imine linear polymers (LPs) and two-dimensional (2D) network β-ketoenamine COFs composed of achiral monomers. We successfully synthesize several 1D imine LPs with mesoscopic helical chirality, comprising achiral C2-symmetric terephthalaldehyde and diamine linkers in a chiral supramolecular transcription system. Leveraging the irreversible tautomerism mechanism within the linker replacement approach, terephthalaldehyde (TPA) units in these helical 1D LPs are substituted with C3-symmetric 1,3,5-triformylphloroglucinol (TP), yielding the corresponding 2D network β-ketoenamine COFs. Crystallinity and helicity of the resultant β-ketoenamine COFs intimately hinge on reaction conditions, including the aldehyde stoichiometry of Tp and TPA, as well as the quantity and concentration of the catalyst employed. Under optimized conditions, the nucleation and growth were precisely governed, achieving a harmonious equilibrium of crystallinity and helicity within the generated 2D network β-ketoenamine COFs, even with covalent bond rupture, recombination, and topological transition (from [C2 + C2] to [C3 + C2]). Impressively, the ground state chirality inherent to helical 1D LPs seamlessly transfers to helical 2D network β-ketoenamine COFs. This study not only offers new perspectives on the development of chiral functional COFs, but also provides fresh insights into the precise control of COFs' microscopic morphology. [ABSTRACT FROM AUTHOR]

The amination of 1,4-benzoquinone monoxime and 5-(hydroximino)quinoline-8(5H)-one with diamines H2N-R-NH2 [R = -(CH2)2-; -(CH2)4-; and trans-cyclohexane-1,4-diyl] gave the corresponding N,N'-bis(4-nitrosophenyl)diamines and N,N'-bis(5-nitrosoquinolin-8-yl)diamines. Stable alkane- and cycloalkanediammonium salts of 1,4-benzoquinone monooxime and 5-(hydroximino)quinolin-8(5H)-one were synthesized. [ABSTRACT FROM AUTHOR]

Objective: This article is focused on synthesis and characterisation of 1,1-(((5-(3,4,5triethoxybenzyl)pyrimidine-2,4-diyl))bis(azanediyl))bis(substituted phenyl methylene))bis(naphthalen-2-ol) moieties and evaluated for antibacterial and antioxidant activities as well as molecular docking and molecular dynamic simulation investigations. Methods: In this article we conducted one-pot three component reactions through Betti type reaction. Agar diffusion method was used to evaluate anti-bacterial properties. The DPPH method was used to determine antioxidant activity results. Results: A series of 1,1-(((5-(3,4,5triethoxybenzyl)-pyrimidine-2,4-diyl))bis(azanediyl))bis(substituted phenyl methylene))bis(naphthalen-2-ol) were synthesized via Betti type reaction and evaluated for their antibacterial and antioxidant activities. Further, all the synthesized compounds were characterized by FT-IR, 1H, and 13C NMR, and mass spectral analysis. Discussion: Molecular docking was carried out to study possible potential binding interaction of synthesized Betti base derivatives with 1NC6 PDB as receptor. The molecular dynamic (MD) was performed to investigate stability of binding interaction of drug-target (protein–ligand) complex. All the synthesized compounds were investigated for their antibacterial and antioxidant activity. Conclusions: Betti base derivatives were synthesized and studied on the basis of computer aided drug design including docking and molecular dynamic (MD) simulations and pharmacologically assessed for antioxidant and antibacterial activity. Molecular docking investigation revealed that compounds showed better binding energies in the range –4.1 to –7.3 kcal/mol suggests that the binding occurs efficiently in the receptor–ligand complex. These Betti base derivatives were synthesized via Betti base protocol at 70oC through one-pot three component reaction with acceptable yields, as cost efficient, high yield, easy workup and environmental friendliness. Afterwards, obtained molecules have characterized by FT-IR, NMR, and Mass spectra which confirms the chemical structure of the synthesized compounds. [ABSTRACT FROM AUTHOR]

In this paper, the influence of diamines on the intrinsic structure and molecular mobility of cellulosic complexes is discussed. Cellulose was pre-swollen by ethylenediamine then put in contact with a series of aliphatic diamines at a stoechiometric ratio. These materials were then characterized by Wide Angle X-Ray diffraction (WAXS) and solid-state 13 C NMR spectroscopy. It was observed by WAXS that diamines are able to swell cellulose along the (010) crystallographic plane and are able to modify unit cell angle γ of cellulose monoclinic structure. Moreover according to their periodicity, ordered- or disordered-phases structures were identified in such cellulosic complexes by Cross Polarization - Magic Angle Spinning (CP-MAS) 13 C NMR spectroscpy. Two-dimensional Wide-line Separation (2D WISE) and T 1 relaxation time 13 C NMR spectroscopy experiments showed that complexes do exhibit molecular motions between 23 and 90 ∘ C. Modulated Differential Scanning Calorymetry (MDSC) further showed the presence of two glass transition temperatures T g , which were attributed, in combination with the 13 C NMR spectroscopy observations through a multiscale approach, to relaxation motions internal to the diamines chemical structure and to the motion of cellulose–diamine planes respectively. [ABSTRACT FROM AUTHOR]

Chiral aromatic alcohols with unique structures have attracted wide attention in asymmetric catalysis for decades. In this study, polymeric micelles with chiral diamine-Ru(II) catalysts in the hydrophobic core for asymmetric transfer hydrogenation of ketones affording chiral aromatic alcohols were presented. Firstly, block copolymers with (1R,2R)-(+)-1,2-diphenyl ethylenediamine (DPEN) in the pendant chain were successfully synthesized by Ring-Opening Metathesis Polymerization (ROMP) using 1,1-dimethyl ethyl N-(2-amino-1,2-diphenylethyl) carbamate (NB-DPEN-Boc) and polyethylene glycol (NB-PEG2000) with norbornene groups as raw materials. The structures of block copolymers P(DPEN)-co-P(PEG2000) were characterized by FT-IR and 1H NMR. Next, Block copolymers with chiral DPEN ligand in the pendant chain coordinate with [RuCl2(p-cymene)]2 to provide amphiphilic polymers with chiral diamine-Ru(II) catalyst. Then, the self-assembly of the amphiphilic polymers in water produced the polymeric micelles with chiral diamine-Ru(II) catalysts in the hydrophobic core. The particle sizes were found to be 65 nm by DLS analysis. The polymeric micelles as catalytic nanoreactors were successfully applied in the asymmetric transfer hydrogenation (ATH) of various ketones in water. The heterogenization of homogeneous catalysts and construction of catalysts for aqueous catalysis demonstrate potential application prospects in the preparation of chiral aromatic alcohols. [ABSTRACT FROM AUTHOR]

A vicinal diamine motif can be found in numerous natural compounds and pharmaceuticals, making it an important synthetic target. Herein, we report a telescoped synthesis of vicinal diamines under continuous flow conditions. This approach involves the electrochemical aziridination of alkenes with primary amines, followed by the strain-release driven ring-opening using various nitrogen nucleophiles. The efficacy of the developed method was demonstrated through the synthesis of diverse symmetrically and non-symmetrically substituted vicinal diamines, as well as vicinal amino azides, which can be further hydrogenated to diamines in flow. Additionally, O-centered nucleophiles were employed for the ring-opening of aziridines in our telescoped synthesis, yielding vicinal amino ethers and alcohol. This process offers a streamlined and efficient pathway for the direct synthesis of valuable products from readily available starting materials, bypassing the isolation of unstable aziridine intermediates. [ABSTRACT FROM AUTHOR]

Developing cross-linked polymers with both low dielectric constant and degradability for microelectronics and sustainability remains a challenge. Herein, a new fluoro-containing dialdehyde monomer (VF) derived from vanillin was synthesized, which was then cross-linked with a tris (2-aminoethyl) amine (TREN) and different diamines (4, 4′-methylenebis (cyclohexylamine) (PACM), 4, 4′-diaminodiphenylmethane (DDM) and 1, 6-hexamethylenediamine (HMDA)) to give three polyimines thermosets, namely VFT-P, VFT-D and VTF-H, respectively, showing controlled comprehensive properties through regulation of imine cross-linked structures. Properties-function relationship of these polyimines was systematically studied and focused mainly on revealing the degradation process and the mechanism of the degradability of polyimines. The results indicated that among these polyimines, VFT-P exhibited superior conventional properties and acid resistance due to its appropriate reactivity, cross-linked density, rigid non-conjugated Schiff base structures, and high free volume. The storage modulus, glass transition temperature, transmittance, and tensile strength of VFT-P polyimines could reach 3.40 GPa, 134 °C, > 97% (at 500–800 nm) and 62.47 ± 3.65 MPa, respectively. Besides, a low dielectric constant of 2.96 at 100 MHz and superior degradability was achieved. This study introduces a facile and effective design strategy to achieve the compatibility of target properties and also offers a potentially sustainable alternative to conventional cross-linked dielectric polymers. [ABSTRACT FROM AUTHOR]

The imidazolidine derivatives were prepared via [1 + 1] condensation of various aldehydes such as 2-Hydroxy benzaldehyde, 2-fluoro benzaldehyde, 2-chloro benzaldehyde, pyridine-2-carbaldehyde, pyrrole-2-carbaldehyde, thiophene-2-carbaldehyde, furan-2-carbaldehyde with N,N′-bis((pyridine-2-yl)methyl)ethane-1,2-diamine (L) in the solvent of acetonitrile and characterized by the appropriate spectroscopic methods (FT-IR, UV–Vis, molar conductivity, 1H and 13C NMR, EI-Mass, X-ray). By coordinating the imidazolidine ring to the metal ions, this ring can be stabilized or hydrolyzed and converted to initial materials. Therefore, in this research, to investigate the effect of imidazolidine ring pressure and the effect of different groups in neutralizing this pressure in coordination with manganese(II) ion, the Manganese(II) complexes of these compounds were synthesized and characterized by FT-IR, UV–Vis spectroscopy, molar conductivity, EI-Mass spectrometry, and X-ray crystallography. The spectroscopic data for the imidazolidine derivatives confirm their formation. The manganese(II) complex of these compounds showed that the imidazolidine ring was unstable due to coordinated and created pressure on the imidazolidine ring and the presence of different groups on the ring does not affect the stability. [ABSTRACT FROM AUTHOR]

Diiminic Schiff bases (DSBs) were proven to be an intriguing candidate for coinage metal-enhanced fluorescence (MEF). DSBs were synthesized via the condensation reaction of salicylaldehyde (SL) and diamines. Silver and copper nanoparticles (synthesized in situ with the reaction of SL) showed significant enhancement of fluorescence selectively depending on the experimental conditions. SL was oxidized to its quinone form, while Ag+ or Cu2+ was reduced to its zero-valent state at the alkaline condition. DSBs acted as reducing as well as stabilizing agents. By changing diamines, the distance between two iminic bonds was manipulated and different extents of MEF were obtained. Detection of highly toxic metal ions is a challenge in an aqueous system in the context of water pollution. Ionic mercury, copper, and silver (released from natural as well as anthropogenic activities) were sensed selectively using turn-on/off fluorescence with a significant limit of detections involving DSBs-induced MEF. Biological compounds are found in remarkable quantities in natural water, creating a long-lasting effect on the food chain and ecology. Cysteine and dopamine were also sensed via the quenching of DSBs-stimulated MEF. Here, we summarized the toxicity of water pollutants and intriguing role of DSBs in coinage MEF for the decontamination of water with plausible mechanism. Such MEF sensed a series of inorganic and biological emerging pollutants in the water system selectively and sensitively. Imine-induced selectivity and manipulation of experimental conditions help to design intriguing sensing platform for the detection of water pollutants. [ABSTRACT FROM AUTHOR]

An efficient, one-pot quantitative procedure for the preparation of benzo[a]pyrano[2,3-c]phenazine derivatives from four-component condensation reaction of 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamine, aromatic aldehydes, and malononitrile in the presence of [(EtO)3Si(CH2)3N+H3][CH3COO−] as basic ionic liquid as catalyst in homogenous solution under solvent-free conditions at 90 °C is described. Simple procedure, high yields, short reaction times, and an environmentally benign method are advantages of this protocol. The [(EtO)3Si(CH2)3N+H3][CH3COO−] can be recovered and reused several times without loss of its activity. [ABSTRACT FROM AUTHOR]

A procedure has been developed for the synthesis of cis- and trans-diastereoisomeric partially hydrogenated pyrido[1,2-a]pyrimidines and pyrido[2,1-b]quinazolines by the four-component cyclization of ethyl trifluoroacetoacetate with two acetaldehyde molecules and propane-1,3-diamine or 2-(aminomethyl)-aniline. The reactions are accompanied by side formation of zwitterionic tetrahydropyrimidinium carboxylate in the reaction with propane-1,3-diamine and of 7-hydroxy-7-(trifluoromethyl)-5,5a,6,7,8,11-hexahydro-9H-pyrido[2,1-b]quinazolin-9-one in the reaction with 2-(aminomethyl)aniline; in the latter case, the cyclization involved one acetaldehyde molecule. The stereochemical structure of the synthesized compounds was determined by 1H, 19F, and 13C NMR spectroscopy and X-ray analysis. A probable mechanism has been proposed for the formation of new hetero-fused pyridine derivatives. [ABSTRACT FROM AUTHOR]

The Chan–Lam reaction conditions were optimized for the synthesis of N-aryl derivatives of adamantane-containing amines. A number of adamantane-containing amines and diamines with different steric hindrances at the primary amino groups were reacted with p-tolylboronic acid under the optimized conditions [0.1 M solution of amine in MeCN, p-tolylboronic acid (2 equiv), DBU (2 equiv), copper(II) acetate (20 mol %), 25°C, 24 h]. The reactivity of the amines was found to strongly depend on their structure, and the maximum yield of the target products reached 74% from the monoamines and 66% from the diamines. [ABSTRACT FROM AUTHOR]

Globally, each day a huge amount of agro-wastes (AWs) have been generated in attending to the demands of the rapidly growing population. The invention of technologies or methods by employing AWs in the synthesis of biologically significant chemical substances seems to be a logical solution to the world's most desired areas of research, environment and health. Herein, we report a sustainable and (agro)waste valorization method for the construction of quinoxalines from α-bromo ketones and aromatic 1,2-diamines using water extract of pomegranate peel ash (WEPA). The developed reactions can be carried out in room temperature using biorenewable WEPA as catalyst as well as aqueous reaction media. It avoids the environment toxic/problematic/volatile organic solvents throughout the procedure from synthesis to purification. The products are purified by recrystallization, and the reactions are conducted under external non-renewable catalyst-free conditions. The freshly prepared WEPA was also characterized by using powdered X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray analyses. The first use of biorenewable aqueous extract for the quinoxalines synthesis, effective applicability of organic solid waste, ambient conditions, and avoid of depleting resources originated substances as reaction media/catalyst/purification or work-up agents/promoters/heating conditions are the significant attributes of this investigation. Therefore, this research may attract researcher's attention towards studying the waste-derived ashes in the materials as well as in synthetic chemistry. [ABSTRACT FROM AUTHOR]

A series of green organic light-emitting diodes (OLEDs) that consisted of a tris-(8-hydroxyquinoline)aluminum emitting layer and an N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) hole transport layer were fabricated and characterized. The NPB layers were formed using a solution process and heated at different temperatures. All the fabricated OLEDs showed similar electroluminescence spectra: however, different heat treatment temperatures resulted in efficiency variations. The peak luminous efficiency revealed a significant increase by ~70% when the temperature was increased from 80°C to 100°C and a dramatic decrease by ~57% after a further increase in temperature to 110°C. As a result, the best performance was observed from the device with a treatment temperature of 100°C; the maximum luminance and luminous efficiency were 7600 cd/m2 and 2.75 cd/A, respectively. [ABSTRACT FROM AUTHOR]

A considerable amount of ultrafine magnetite as the iron source will end up in the tailing dams since the magnetic separation process markedly drops as the particle size. Cationic reverse flotation could be one of the main alternatives for recovering ultrafine magnetite. As a systematic approach, this study explored the flotation efficiency and interaction mechanisms of two biodegradable ether amines (diamine and monoamine) to separate ultrafine quartz from magnetite (− 20 µm). Several assessments (single and mixed mineral flotation, zeta potential, contact angle, surface tension measurement, turbidity, and Fourier transform infrared) were conducted to explore the efficiency of the process and the interaction mechanisms. Results indicated that ether diamine and monoamine could highly float ultrafine quartz particles (95.9 and 97.7%, respectively) and efficiently separate them from ultrafine magnetite particles. Turbidity assessments highlighted that these cationic collectors could aggregate magnetite particles (potentially hydrophobic coagulation) and enhance their depression. Surface analyses revealed that the collector mainly adsorbed on the quartz particles, while it was essentially a weak interaction on magnetite. [ABSTRACT FROM AUTHOR]

The reaction of (perfluoroalkyl)furan-3(2H)-ones and β-diketone containing an acetal moiety with (hetero)aromatic 1,2-diamines was studied. Quinoxalines and pyrido[3,4-b]pyrazine bearing the enaminoketone fragment were ynthesized by the regioselective addition of a dinucleophile at the α-dicarbonyl moiety of polyketones. In the case of β-diketone containing acetal and ester groups, the conversion involves the α-ketoester moiety to form a quinoxalinyl-substituted 2,3-butanedione. All products were characterized by NMR spectroscopy and X-ray diffraction. [ABSTRACT FROM AUTHOR]

Objective: To test whether recombinant human diamine oxidase (rhDAO) with a mutated heparin-binding motif (mHBM), which shows an increased alpha-distribution half-life, prevents histamine-induced hemodynamic effects. Material: Thirty-eight female guinea pigs were either pretreated with rhDOA_mHBM or buffer. Treatment and methods: Guinea pigs received a continuous infusion of histamine. Heart rate (HR), body core temperature and mean arterial pressure (MAP) were measured and blood was collected. Results: Continuous intravenous infusion of 8 µg/kg/min histamine increased mean peak plasma histamine levels from 5 (± 0.3 SEM) to 28 ng/mL (± 4.9 SEM) after 30 min but had no effect on oxygen saturation. Guinea pigs pretreated with 4 mg/kg rhDAO_mHBM showed lower mean HR (p = 0.008), histamine plasma concentrations (p = 0.002), and higher body core temperatures at the end of the histamine challenge (p = 0.02) compared to controls. Cessation of histamine infusion led to a rebound increase in MAP, but this hemodynamic instability was prevented by rhDAO_mHBM. Pretreatment with 4 mg/kg rhDAO_mHBM reduced urinary histamine (p = 0.004) and 1-Methylhistamine (p < 0.0001) concentrations compared to controls. Conclusions: Prophylactic infusion of rhDAO_mHBM prevents hemodynamic effects in a guinea pig model of continuous histamine infusion. These findings might help in the translation from animals to humans and in the selection of the optimal dosing of rhDAO_mHBM during human histamine challenge studies. [ABSTRACT FROM AUTHOR]

Multicomponent polymerizations (MCPs) are powerful tools to synthesize functional polymers with great structural diversity, low cost and high efficiency, which usually generate single polymer product. Herein, a robust one-pot diamines, CS2 and monoisocyanide-participated catalyst-free polymerization was developed at room temperature to produce polythiourea and thioformamide simultaneously in equal equivalent, which was featured with cheap monomers, simple operation and mild condition, affording various polythioureas with high Mws of up to 47500 g/mol in high yields of up to 98%. Polythioureas with varied chain composition and sequence-controlled structure could be synthesized in 62 g-scale from copolymerization or multicomponent tandem polymerization, enabling facile tuning of thermal property, crystallinity, mechanical property, and fluorescence. The abundant irregular hydrogen bonds endowed the polythioureas excellent glassy state self-healing property at room temperature or below 0 °C. This polymerization provided an efficient and economic approach to access functional polythioureas. [ABSTRACT FROM AUTHOR]

The design and development of highly permeable, selective and stable polymer membranes are great challenges in the gas separation industry. Herein, we constructed two intrinsic microporous polyimides (6FPCA and 6FMCA) derived from two isometric diamines (PCA and MCA), which were synthesized by palladium catalyzed C—N coupling reaction. The PCA and MCA diamines contain a hollow beaded structure of 2,2′-paracyclophane as a building block with a specified window size of 3.09 Å. The chemical structures of monomers, polyimides were confirmed by NMR, FTIR, and elementary analysis. 6FPCA and 6FMCA exhibit good solubility, excellent thermal stability, and mechanical properties. 6FPCA exhibits much larger microporosity (434 versus 120 m2·g−1), FFV (0.22 versus 0.15), d-spacing (6.9 versus 5.9 Å), and over 10 times higher permeability with a very little decrease in selectivity than the corresponding polyimide (6FpA) with a plane structure, which remarkably increased their separation performance from far below the 2008 Robeson Upper bounds to reach these limitations for O2/N2 and CO2/CH4. Additionally, the 6FPCA also demonstrates good plasticization resistance, moderate aging properties, and high CO2/CH4 mixed-gas separation performance. These results indicate that paracyclophane subunit can be successfully incorporated into polymers to enhance their ultra-microporosity and separation properties, which open a new avenue for developing high performance gas separation membranes with topological ultra-micropores. [ABSTRACT FROM AUTHOR]

A three-component approach was conducted to adeptly prepare a new series of (Z)-bis(N-phenylthiazol-2(3H)-imines. The newly synthesized compounds were prepared by refluxing a ternary mixture of phenyl isothiocyanate, the suitable α-bromoketones, and alkane-linked diamines in ethanol. Reaction conditions were optimized by comparing the yield of the final product under various bases, solvents, temperatures, and base-to-starting-materials molar ratios. The intended hybrids were produced with 85–96% yields while using ethanol at 80 °C for 3–5 h in the presence of anhydrous sodium acetate. The ascribed configuration of new products as well as the regioselectivity of the one-pot reaction were confirmed using both spectral data (1D and 2D NMR) and DFT-calculation techniques. [ABSTRACT FROM AUTHOR]

The reaction of isoalantolactone with primary amines or piperazine proceeds under mild conditions with high stereoselectivity to give 11,13-isoalantolactone dimers connected by an alkyldiamine or piperazine linker. The reaction of isoalantolactone with propargylamine hydrochloride afforded the corresponding 13-propargylamino-11,13-dihydroisoalantolactone or 13-propargylamino-N-bis(11,13-dihydroisoalantolactone). The synthesized propargylamines showed high activity in the Cu-catalyzed cycloaddition with organic azides. The newly synthesized compounds with a bis-eudesman structure were found to exhibit antibacterial activity against strains of Staphylococcus aureus, Bacillus cereus, and Escherichia coli. [ABSTRACT FROM AUTHOR]

Ascorbic acid could be applied as a recyclable organocatalyst for the preparation of pyrroles via Paal–Knorr condensation of hexane-2,5-dione with various mono- and diamines. The reaction proceeded smoothly to afford the desired products in moderate to excellent yields under solvent-free conditions. Moreover, the investigations on diamine reactants revealed that both the amount of loaded catalyst and steric or electronic property of substrates are major factors in the selective formation of the corresponding bis-pyrrole or mono-pyrrole products. Density functional theory methods have been employed to provide a better understanding of the catalytic mechanism of ascorbic acid in this reaction. The optimized calculations pointed out the presence of three possible bifunctional hydrogen bond donor sites and one hydrogen bond acceptor site in the molecular structure of ascorbic acid. Although all four possible complexes were studied, the two bidentate hydrogen bond complexes between ascorbic acid and the carbonyl group of hexane-2,5-dione (average hydrogen bond distance ~ 1.8–1.9 Å) were the most stable complexes. MEP maps and NBO analysis of the complexes are in consistent with the obtained free energy. Furthermore, the reduced HOMO–LUMO energy gap values support an increase in the chemical reactivity of catalyzed hexane-2,5-dione toward aniline. Ascorbic acid could be applied as a recyclable bifunctional hydrogen bond organocatalyst for the preparation of pyrroles via Paal–Knorr condensation of hexane-2,5-dione with various mono- and diamines. The DFT calculations support the existence of bidentate hydrogen bond interactions of ascorbic acid with substrates which facilitates the reaction. [ABSTRACT FROM AUTHOR]

A green one-pot synthesis of 3,3′-(1,4-phenylene)bis[2-(furan/thiophen/pyrrol-2-yl)-2,3-dihydro-quinazolin-4(1H)-one] derivatives in 85–90% yield have been developed by using 1H-1,3-benzoxazine-2,4-dione, furane-, thiophene-, or 1H-pyrrole-2-carbaldehyde, and benzene-1,4-diamine as starting materials in the presence of L-proline as catalyst in ethanol at 65–70°C for 90–120 min. The anticancer potential of the synthesized compounds against SKOV3 and DU145 cells has been evaluated, and 1-methyl-5-nitro-1H-pyrrol-2-yl derivative 4h exhibited the prominent activity against SKOV3 and DU145 cells with an IC50 values of 8.5 and 7.9 µM, respectively. The in silico study of the most active compound (–10.8 kcal/mol) showed good binding energies toward human mitogen-activated protein kinase. [ABSTRACT FROM AUTHOR]

The reactions of 4-aryl-1-tosyl-1,2,3-triazoles with substituted primary 2- or 4-nitroanilines, catalyzed by dirhodium tetrapivalate were used to synthesize stable (Z)-N-aryl-N'-tosylethene-1,2-diamines. The analogous reaction of 4-phthalimido-1-tosyl-1H-1,2,3-triazole with 2-bromo-4-nitroaniline proceeded upon heating in the absence of catalyst, providing the first example for non-catalytic insertion of a carbene generated from 1-sulfonyl-1,2,3-triazole into an N–H bond. All ethene-1,2-diamines were isolated without resorting to chromatographic purification. The synthesized ethene-1,2-diamines contained two NH groups in a cis relationship and present interest as new bidentate ligands, as well as substrates for the synthesis of N,N-heterocycles. [ABSTRACT FROM AUTHOR]

Catalyzed by BiCl3, aromatic o-diamines reacted with ketones efficiently to produce 1,5-benzodiazepines in good to excellent yields by condensation–cyclization reaction. Using aldehydes as substrates, mono- or disubstituted benzimidazoles were obtained as the final products. All reactions were carried out under mild reaction conditions and showed good functional group compatibility. [ABSTRACT FROM AUTHOR]

The review presents approaches to the synthesis of trifluoromethyl-containing N,O,S-heterocyclic compounds such as imidazolidin-2-ones(thiones), 1,2,4-triazine-3-thiones(ones), 1,2,4-triazine-3-amines, bis(trifluoromethyl)-2,3-dihydropyrazine-1,4-dioxides based on reactions of perfluorobiacetyl with bi- and trifunctional nucleophilic agents: urea, N- and N,N′-substituted ureas, thiourea, thiosemicarbazide, semicarbazide hydrochloride, aminoguanidine bicarbonate, and N,N′-dihydroxy-2,3-dimethylbutane-2,3-diamine. The reaction of 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazilidin-2-one with urea in N,N-dimethylacetamide at elevated temperature afforded bis(trifluoromethyl)-glycoluril. Monosubstituted N-alkyl(aryl)-4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidin-2-ones reacted with urea under similar conditions to give 1-alkyl(aryl)bis(trifluoromethyl)imidazooxazoles. The condensation reaction of trifluoromethyl-containing imidazolidin-2-ones(thiones) with thiourea and NH4SCN in a dipolar aprotic solvent at elevated temperature resulted in thioglycolurils, thioxoimidazothiazolones, and oxoimidazothiazolones. The first nitrogen-containing heterocycles containing a CF3 group at the vicinal position to the N-O fragment were synthesized by the reaction of perfluorobiacetyl with N,N′-dihydroxy-2,3-dimethylbutane-2,3-diamine. [ABSTRACT FROM AUTHOR]

As replacements for bisphenol-A, new bio-based and reactive epoxy-amine coatings have been investigated in this study. Bio-based precursor, epoxy-functionalized tung oil (ETO) was synthesized using glycidyl methacrylate (GMA) and tung oil via a Diels–Alder reaction according to our previous work. The new ETO-diamine-cured systems were prepared with the equivalent molar ratio at room temperature. ETO was cured with acyclic aliphatic (Jeffamine D400) and cyclic aliphatic (Epicure 3300) amines, at four temperatures ranging from 25 to 150°C. The coatings were then compared in terms of their thermal and mechanical properties. The cured coatings were analyzed by IR, thermogravimetric analysis (TGA), and gel content tests. TGA analysis showed that the epoxide-diamine polymers demonstrated thermal stability up to 170°C. The mechanical properties of the films were investigated by pendulum hardness, pencil hardness, cross-hatch adhesion, pull-off adhesion, impact resistance, reverse resistance, and chemical resistance testing. While all the cured systems exhibited good pencil hardness, cross-hatch adhesion, impact resistance, and reverse resistance properties, the epoxide-acyclic diamine system demonstrated greater pendulum hardness and notable pull-off adhesion at 150°C. The research demonstrates the potential for greener and more reactive tung oil-based epoxide coatings with enhanced properties. [ABSTRACT FROM AUTHOR]

The inhibitory effect of di-imine-SB namely ((N1Z, N4E)-N1, N4-bis (4 (dimethylamino) benzylidene) butane 1,4-diamine) on X65-steel in 1 M HCl has been investigated experimentally and theoretically. The electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and weight loss outcomes display the anticorrosion properties of "di-imine- SB". The inhibitory efficiency exceeds 90% at the optimal concentration of 1 × 10–3 M "di-imine- SB". The metal surface was examined further using scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The effectiveness of the di-imine-SB is returned into its adsorption on X65-steel surface and found in agreement with Langmuir adsorption isotherm. According to the standard Gibbs free energy of adsorption (Δ G ads ∘) , di-imine-SB adsorption tends to be chemical rather than physical, it increases the activation energy ( E a ) of metal dissolution reaction and makes it hard to occur. The PDP data suggested anodic and cathodic type of the di-imine-SB inhibitor. Meanwhile, increasing the resistance of X65-steel to 301 Ω cm2 after adding 1 mM of di-imine-SB confirms its protective effect. Whereas, the positive value of the fraction of electron transference (ΔN, 0.746), confirms the affinity of di-imine-SB to share electrons to the partially filed 3d-orbital of Fe forming strong protective film over X65-steel surface. Aided by Monte Carlo (MC) simulation, the calculated adsorption energy (Eads) suggests excessive adsorption affinity of di-imine-SB on metal surface over the corrosive chlorides and hydronium ions. A good correlation between the theoretical hypothesis and the experimental inhibition efficiency has been achieved. The comparative study showed the superior of the di-imine-SB as potential corrosion inhibitor compared with those reported before. Finally, global reactivity descriptors; electron affinity (A), ionization potential (I), electronegativity (χ), dipole moment (µ), global hardness (η ), electrophilicity index and, Fukui indices were also calculated and found well correlated to the reactivity of di-imine-SB. [ABSTRACT FROM AUTHOR]

In this paper, the stable synthesis of benzimidazoles catalyzed by reduced graphene oxide/palladium nanoparticle bonded to N,N'-bis(2-aminophenyl)-1,2-ethanediamine (RGO/N-ligand-Pd(0) nanocomposite) through acceptorless dehydrogenative coupling (ADC) of 1,2-phenylenediamine and benzyl alcohol is investigated. The main advantage of this report is the use of RGO/N-ligand-Pd(0) nanocomposite as a new and highly efficient heterogeneous catalyst for the synthesis of a wide range of 2-substituted benzimidazoles using the benign environmental process ADC, because in this process valuable by-products of water and hydrogen gas are produced. The prepared catalyst was identified using various techniques. The results showed that the N-ligand-Pd(0) anchored steadily to the GO nanosheets. The current method has several advantages such as short reaction time, large surface area, and high thermal stability of the catalyst, the ability to reuse the catalyst several times without significant loss of catalytic activity, and the use of benzyl alcohol as a primary material. [ABSTRACT FROM AUTHOR]

It was shown that the optical and dielectric properties of polyimides (PIs) are affected by both the presence of an alicyclic fragment and the non-coplanarity of the structural elements of the polymer chain. The combination of these factors contributed to an increase of the transparency of the PIs in the optical range and a decrease of the dielectric constant. It was determined that the introduction of 20 mol.% adamantane-containing diamine into the PI structure contributed to its more complete amorphization and increased its transparency. [ABSTRACT FROM AUTHOR]

9,9-Bis(4-iodophenyl)xanthene (BIPX) was prepared in good yield by the sequential diazotization–iodination of 9,9-bis(4-aminophenyl)xanthene with a KI/NaNO2/p-TsOH system in acetonitrile at room temperature. A series of novel aromatic polyamides (PAs) were prepared by a carbonylation polymerization of BIPX, aromatic diamines and carbon monoxide in DMAc with Pd(PPh3)2Cl2 as the catalyst in the presence of PPh3 and 1,8-diazabicyclo[5,4,0]-7-undecene (DBU). The resulting PAs bearing inherent viscosity of 0.65–0.75 dL/g were amorphous and readily soluble in organic polar solvents such as NMP, DMF, DMAc, DMSO and Py. These new PAs exhibited good thermal stability with glass-transition temperature of 241–359 °C, 10% weight loss temperature of 480–492 °C and char yield of 47.8–56.7% at 800 °C in nitrogen. Meanwhile, all obtained PAs exhibited low water uptake of 0.98–2.37%, and their transparent, tough and flexible films presented high optical transparency with a cutoff wavelength in the 322–370 nm range and had the tensile strength in the range of 73.4–83.4 MPa, elongation at breakage of 6.7–13.8% and tensile modulus of 1.6–2.2 GPa, respectively. [ABSTRACT FROM AUTHOR]

Racemic 1-(adamantan-1-yl)propane-1,2-diamine was synthesized from trans-2-(adamantan-1-yl)-3-methylaziridine, and its optical resolution was achieved with the use of L-malic acid. The isolated (1S,2R)-stereoisomer was derivatized with benzil, and enantiomeric purity of the resulting (2S,3R)-2-(adaman-tan-1-yl)-3-methyl-5,6-diphenyl-2,3-dihydropyrazine was determined by chiral HPLC. The reaction of (1S,2R)-1-(adamantan-1-yl)propane-1,2-diamine with carbon disulfide gave (4S,5R)-4-(adamantan-1-yl)-5-methylimidazolidine-2-thione whose absolute configuration was established by X-ray analysis. Racemic and optically pure (1S,2R)-1-(adamantan-1-yl)propane-1,2-diamines were used to obtain ligands and their metal complexes, and the latter were studied as catalysts in model epoxidation, Michael, and Henry reactions. Enantiodivergence was observed in the Henry reaction catalyzed by structurally related ligands. [ABSTRACT FROM AUTHOR]

Polyureas are an emerging class of materials which have broad potential applications because of their versatility, complex internal structures. Here polyureas are prepared by the reaction of hexamethylene diisocyanate with either aliphatic or aromatic diamines. Multiple characterization techniques revealed that polyurea materials are porous in nature and stable up to 250 ℃. Further, CP TOSS (Cross Polarized Total Sideband Suppression) 13C solid state NMR revealed the formation of polyurea. PXRD showed that some polyureas were crystalline and formed a network structure through hydrogen bonds which served as a cross linker. Their highly insoluble nature in polar and non-polar solvents, layered structure makes them apt heterogeneous catalysts. A higher catalytic performance was detected in Knoevenagel condensation reaction between aromatic aldehyde and malononitrile in the presence of polyurea. A decrease in the catalytic activity was detected in the 7th recycle tentatively due to the adsorption of water molecule. [ABSTRACT FROM AUTHOR]

Dynamic dielectric properties of an isotactic polypropylene matrix grafted with maleic anhydride (CA 100) and then crosslinked by polyether amine molecules and reinforced with different weight percentages of graphite nanoplatelets (GNPs), KNG180, were studied for the first time and compared to those obtained by DMA (Dynamic Mechanical Analysis). The main objective of this work was to investigate the reinforcement effect of GNPs focusing on the GNPs/matrix interfacial adhesion using dynamic dielectric relaxation spectroscopy in the frequency range from 0.1 Hz to 1 MHz and temperature range from 20 to 140 °C. The obtained interfacial polarization increments Δ ε MWS from MWS (Maxwell Wagners Sillars) relaxation showed a threshold value of 3% in weight of KNG180. This analysis suggests that interfacial compatibility between matrix and fillers in the case of nanocomposite KNG180 3 wt% is higher than those of other nanocomposites. A new plasma treatment was used to modify graphite nano-fillers to produce different types of nanocomposites. The 5 wt% plasma treated graphite nanocomposite shows a good dispersion of the nano-fillers but also a high value of Δ ε MWS , which is an indication of high graphite/graphite interaction. This evolution could show that this material can be close to the formation of an electrical percolation network. [ABSTRACT FROM AUTHOR]

To develop a variety of algaecides for harmful algae control that cause water pollution, we synthesized a series of 79 derivatives based on the structure of N1-benzyl-N3, N3-diethylpropane-1,3-diamine and analyzed their structure-activity relationships toward a harmful and a harmless algal species. Among the derivatives, the best algicidal activities with LC50 values of 0.49 (compound 24) and 0.42 µM (compound 34) in Cyanobacteria, respectively were achieved when CH3 and F groups were substituted at the R2 position, with CH3CH3 group at the R3 position, and amine chain length 3 at the R4 position after fixing Cl substituent group at the R1 position of the benzaldehyde group. The compounds 24 and 34 decreased the chlorophyll content of treated groups by approximately 75–80% as compared to the control. Algicidal activities for harmful algal species were as follows, in the order of greatest to the least: Microcystis sp. > Microcystis aeruginosa > Hererocapsa circularisquama > Chattonella marina > Heterosigma akashiwo. The acute toxicities of compounds 24 and 34 against Daphnia magna showed EC50 values of 20.18 and 22.32 µM, respectively, which were approximately 46.4 and 44.69 times higher than the LC50 value against Microcystis sp., showing low ecotoxicity. In the case of Danio rerio, they showed very low ecotoxicity with EC50 values of 94.97 and 45.97 µM, respectively. These results indicate that compounds 24 and 34 could be potential agents for selectively controlling harmful algal blooms. [ABSTRACT FROM AUTHOR]

Present embodiment is a study of evaluation of antioxidant property of bis-adamantylated resorcinol [4, 6- bis(1-adamantyl) resorcinol] 1b on nylon-12 as base polymer using differential scanning calorimetry (DSC) via oxidation induction time (OIT) studies. The DSC curves of 0.5% 1b mixed nylon-12 showed unusual pattern as it showed initially a hint of onset of oxidation but no prominent exotherm subsequently, thereby indicating no further oxidation of material. This behaviour showed that the 1b can be used as an antioxidant for variety of polymers. In this study, 1b has been functionalized to corresponding diamines 1bb which can be used for synthesis of bis-imides. 1b can itself be used as a precursor material for other polymers and active pharmaceutical ingredients. [ABSTRACT FROM AUTHOR]

1-Pyrenylboronic acid (1-PBA) is a type of a reactive matrix useful for the analysis of polyfunctional compounds by MALDI mass spectrometry. It exhibits conventional matrix properties (absorption and transfer of laser radiation energy) and acts as a derivatizing reagent capable of interacting with vicinal functional groups under mild conditions and forming covalent adducts. Pyrenyl group in its structure, which has high ability to absorb UV laser quanta, ensures the detection of analyte derivatives containing a 1-PBA residue as radical cations, which is untypical for MALDI. The effectiveness of its use was earlier proved for compounds containing 1,2-diol fragments. This work presents additional cases of using this reactive matrix in the analysis of practically significant compounds of this type, demonstrating that 1-PBA can also react with distant OH groups. Many examples show its applicability to the study of various α-hydroxy acids and vicinal aminols and capability of forming cyclic covalent adducts with 1,2-diamines. [ABSTRACT FROM AUTHOR]

A series of new and significative γ-butyrolactone-based phenazines were synthesized through two-step one-pot five-component reactions of 2-hydroxy-1,4-naphthoquinone, a variety of aromatic aldehydes, benzene-1,2-diamine, tetronic acid, and ammonium acetate in glacial acetic acid. The synthesis proceeded via condensation, Michael addition, tautomerization sequence of steps. All the synthesized compounds were fully characterized by spectral data. [ABSTRACT FROM AUTHOR]

N,N′-Diarylation of alkane- and oxaalkane-α,ω-diamines has been performed for the first time under the Chan–Lam coupling conditions using p-tolylboronic acid as a model reagent. Optimization of the conditions showed that best results were obtained with 4 equiv of p-tolylboronic acid, 3 equiv of DBU as a base, 20 mol % of copper(II) acetate as a catalyst, and a substrate concentration of 0.05 M. The arylation of oxadiamines provided better yields (up to 80%) in comparison to diamines. [ABSTRACT FROM AUTHOR]

A one-step synthesis of 1-(isocyanatomethyl)-3,5-dimethyladamantane with a yield of 87% is described. The reaction of 1-(isocyanatomethyl)-3,5-dimethyladamantane with aliphatic diamines gave a series of symmetrical 1,3-disubstituted ureas with 63–99% yields. The synthesized ureas hold promise as human soluble epoxide hydrolase inhibitors. [ABSTRACT FROM AUTHOR]

High molecular weight poly(amide-imide)s containing cardo structures were readily prepared by a supported palladium-catalyzed carbonylation polymerization of diiodo imide monomers, aromatic diamines containing cardo groups, and carbon monoxide. Polycondensation reaction proceeded effectively in N,N-dimethylacetamide (DMAc) at 100 °C in the presence of a bidentate phosphino-modified magnetic nanoparticles-anchored palladium complex [2P-Fe3O4@SiO2-PdCl2] as catalyst and 1,8-diazabicyclo[5,4,0]-7-undecene (DBU) as base under 1 atm of CO, yielding a series of new poly(amide-imide)s with inherent viscosities up to 0.95 dL/g. All the polymers obtained were easily soluble in some strong polar aprotic organic solvents and could be cast into transparent, flexible and tough films from their DMAc solutions. These cardo poly(amide-imide)s displayed high thermal stability with the glass transition temperatures ranging from 237 to 265 °C, the temperatures at 5% weight loss ranging from 433 to 475 °C in nitrogen. These PAI films also exhibited good mechanical behavior and high optical transparency. The present method provides the flexibility of incorporating different ratios of imide and amide groups in the polymer backbone in a controlled manner and eliminates the possibility of postpolymerization curing due to the imide moiety being preformed. Importantly, the supported palladium catalyst can be conveniently separated from the polymer by simply using an external magnetic field and recycled at least 8 times without apparent loss of catalytic efficiency. [ABSTRACT FROM AUTHOR]

Cyclic biscarbonates were synthesized from CO2 and diepoxides in the presence of a chromium(III) salen complex. The effect of the reaction conditions on the process kinetics, recorded by monitoring the CO2 absorption during the reaction, has been studied for the first time. After complete conversion of diepoxides to cyclic biscarbonate, the same catalytic system was used in the reaction of biscarbonates with diamines to form polyhydroxyurethanes. The thermal characteristics of the synthesized polymers are mainly determined by the structure of the diepoxide and, to a lesser extent, by the nature of the amine used in the second stage of the process. [ABSTRACT FROM AUTHOR]

A series of N,N′-disubstituted bis-ureas containing a lipophilic 4-(trifluoromethoxy)phenyl fragment were synthesized in 58–80% yields by reaction of 4-(trifluoromethoxy)phenyl isocyanate with aliphatic diamines. The synthesized compounds are promising as inhibitors of human soluble epoxide hydrolase. [ABSTRACT FROM AUTHOR]

Polymers based on the furanic compounds derived from renewable carbohydrates have seen massive growth due to their unique properties and increasing concerns about sustainability and environmental challenges. In this study, fully bio-based four new linear ion-exchange polyamides were synthesized by interfacial polymerization of bisfuran diamine monomer (BFN). The BFN monomer is prepared by condensing 2-aminomethyl furan with levulinic acid using an acid catalyst. The bisfuran polyamides are generally considered hydrophilic, with an observed swelling capacity range from 108 to 192%. The ion exchange capacity range was observed from 2.19 to 2.35. The thermal properties of the bisfuran polyamides were studied with differential scanning calorimetry and thermal gravimetric analysis. The glass transition values were ranged from 162.2 to 122.1 °C, and the 1% mass loss at temperatures was above 215 °C. An X-ray diffraction study proves amorphous nature with some degree of crystallinity at θ = 20°. [ABSTRACT FROM AUTHOR]

A three-component reaction of ethyl trifluoropyruvate, methyl ketones, and ethylenediamine or 1,3-diaminopropane afforded hexahydropyrrolo[1,2-a]imidazol-5-ones and hexahydropyrrolo[1,2-a]pyrimidin-6-ones. When using an excess of ethyl trifluoropyruvate in reactions with acetone and diamines, dipyrrolo[1,2-a:2',1'-b]imidazole-3,8-dione and dipyrrolo[1,2-a:2',1'-b]pyrimidine-3,9-dione were obtained. An aldol mechanism for the formation of the bi- and tricyclic compounds was proposed, and their diastereomeric structure was established. Some of the obtained heterocycles were found to possess analgesic activity. [ABSTRACT FROM AUTHOR]