Showing papers on "Triazene published in 2017"

Divergent Asymmetric Synthesis of Polycyclic Compounds via Vinyl Triazenes

Abstract: Vinyl triazenes were obtained by enantioselective [2+2] cycloaddition reactions of bicyclic alkenes with 1-alkynyl triazenes in the presence of a RuII catalyst with a chiral cyclopentadienyl ligand. These triazenes serve as unique vinyl cation surrogates. Under acidic conditions, the triazene functionality can be replaced with a variety of groups, including halides, alkoxides, sulfoxides, amides, arenes, and heteroarenes, thus providing efficient access to a pool of chiral polycyclic compounds.

Divergent Synthesis of Porous Tetraphenylmethane Dendrimers.

Abstract: Tetraphenylmethane-ethynylene-based shape-persistent dendrimers are a new class of nanoobjects with an intriguing 3D architecture. We report an efficient divergent strategy for their synthesis based on the Sonogashira Pd-catalyzed coupling of terminal alkynes with aryl iodides. As repeat unit, we prepared a tetraphenylmethane derivative bearing a terminal alkyne and three triazene moieties. Coupling of this building block to tetrakis(p-iodophenyl)methane afforded, after triazene activation, a dodecaiodo-terminated first generation dendrimer, which was transformed by another Sonogashira coupling into a methoxy-terminated second generation dendrimer with persistent globular shape and well-defined cavities. This work also unveils new aspects of triazene chemistry, i.e., the unprecedented efficient generation of an azo compound by mixing of a triazene with phenol.

π-Conjugated Triazenes: Intermediates That Undergo Oxidation and Substitution Reactions.

Abstract: Novel reactivity for π-conjugated triazenes is herein reported. This observed and unprecedented triazene reactivity gave access to oxidation and substitution reactions. These transformations include successful synthesis of aldehydes, ketones, ethers, and sulfides from readily available organic azides via π-conjugated triazene intermediates. Notably, the afforded adducts were obtained in good yields, at room temperature, and in the absence of added metal catalysts.

Asymmetrically substituted triazenes as poor electron donor ligands in the precursor chemistry of iron(II) for iron-based metallic and intermetallic nanocrystals

Abstract: Triazene ligands are introduced, for the first time, in the precursor chemistry for their ability to afford oxygen-free molecular precursors of Fe0 nanoparticles. For this purpose, we synthesized new asymmetric triazene ligands t-BuNN-NHR (R = Et, i-Pr, n-Bu) featuring different alkyl substituents at 1,3-N centers, as well as a symmetric ligand t-BuNN-NHt-Bu and used them to develop novel heteroleptic monomeric FeII triazenide derivatives [Fe(t-BuN3R)2(TMEDA)] (where TMEDA = tetramethylethylenediamine). A range of physico-chemical studies such as FT-IR, TG-DTA, 1H & 13C NMR, mass spectrometry, single crystal X-ray structure analysis, cyclic voltammetry and Mossbauer spectroscopy were used to characterize these newly synthesized ligands and FeII derivatives. One representative derivative [Fe(t-BuN3Et)2(TMEDA)] was evaluated as a precursor for the synthesis of metallic Fe0 and intermetallic Al13Fe4 nanoparticles by the chemical solution deposition method.

Ultrafast Dynamics of a Triazene: Excited-State Pathways and the Impact of Binding to the Minor Groove of DNA and Further Biomolecular Systems

Abstract: Many synthetic DNA minor groove binders exhibit a strong increase in fluorescence when bound to DNA. The pharmaceutical-relevant berenil (diminazene aceturate) is an exception with an extremely low fluorescence quantum yield (on the order of 10–4). We investigate the ultrafast excited-state dynamics of this triazene by femtosecond time-resolved fluorescence experiments in water, ethylene glycol, and buffer and bound to the enzyme β-trypsin, the minor groove of AT-rich DNA, and G-quadruplex DNA. Ab initio calculations provide additional mechanistic insight. The complementing studies unveil that the excited-state motion initiated by ππ* excitation occurs in two phases: a subpicosecond phase associated with the lengthening of the central N═N double bond, followed by a bicycle-pedal-type motion of the triazene bridge, which is almost volume-conserving and can proceed efficiently within only a few picoseconds even under spatially confined conditions. Our results elucidate the excited-state relaxation mechanism...

Gold‐Catalyzed Synthesis of 1,3‐Diaminopyrazoles from 1‐Alkynyltriazenes and Imines

Abstract: A new procedure for the synthesis of highly substituted 1,3-diaminopyrazoles is described. As substrates, we have employed 1-alkynyltriazenes and imines. The formation of pyrazoles was achieved by two-fold C-N coupling reactions in the presence of (JohnPhos)AuCl and AgNTf2 as catalyst precursors. The regioselectivity of the reaction was inferred from a crystallographic analysis of one reaction product. This article is protected by copyright. All rights reserved.

Synthesis of 5,5′-azoxybistetrazole via nitration and de-oxygen rearrangement of triazene

Abstract: An efficient approach to synthesize 5,5′-azoxybistetrazoles has been achieved via the treatment of tetrazolyl triazenes with fuming nitric acid and acetic anhydride in a two-step one-pot reaction. Herein, 5,5′-azoxybistetrazole is proposed to be formed via a nitroso triazene intermediate generated from tetrazolyl triazene by nitration and de-oxygen rearrangement. All compounds were fully characterized using IR, 1H and 13C NMR spectroscopy, and HRMS. In the case of 2,2′-dimethyl-5,5′-azoxybistetrazole (2a), single crystal X-ray structuring and 15N NMR spectroscopy were also performed. The calculations predict that 2f has a detonation velocity of 8066 m s−1 and a detonation pressure of 25.8 GPa.

Corrosion Inhibition of Brass in 0.5 M HNO3 by 3-hydroxy-3-(4-chlorophenyl-1-(4-sulphonato (sodium salt)) Phenyl Triazene (HCST): Adsorption and Thermodynamic Study

Abstract: Accepted on 8 th January 2016 _____________________________________________________________________________ ABSTRACT The effect of the concentration and nature of novel 3-hydroxy-3-(4-chlorophenyl-1-(4-sulphonato (sodium salt)) phenyl triazene (HCST) on corrosion and dezinfication of 70/30 brass in 0.5N HNO3 solution has been investigated by weight loss method. Inhibition efficiency of this corrosion inhibitor was also evaluated at different temperature ranging from 303K-333K. It was observed that HCST showed 88.13% inhibition efficiency at 303K upto 0.005M concentration of inhibitor. Weight loss method has been used to analyze the corrosion behavior of the brass in the absence and presence of different concentration of inhibitor. The corrosion inhibition efficiency increases with increasing concentration of inhibitor and decreases with rise in temperatures. Activation energy (Ea), Enthalpy (∆H), Entropy (∆S) and Gibbs free energy (∆G) for corrosion process have also been calculated. The adsorption behavior of HCST on brass surface has been found to obey Langmuir adsorption isotherm. Results reveal that hydroxytriazenes can be potential corrosion inhibitors.

Synthesis and biological evaluation of glycosides containing triazene-chalcones

Abstract: By combining triazenes with chalcones, we designed and synthesized 12 novel glycosides. The antiproliferative activity of all products was screened using an MTT assay against MGC803 cells and PC-3 cells. Compound $$\mathbf{2b}_{6}$$ displayed more potent antiproliferative activity than dacarbazine. Furthermore, we explored the preliminary structure activity relationship of all target compounds. The derivatives in this work might serve as bioactive fragments and lead compounds for developing more potent cytotoxic agents.

Unprecedented Cyclic Isomer of Triazenes: A Computational Identification

Abstract: Isomerism is very important in chemistry. Over the past 65 years, the energy-rich N3R3 family has received considerable attention both experimentally and computationally. Up to now, four isomeric types of N3R3 have been identified, i.e., triazenes I, triimides II, iso-triazenes III, and cyclo-triazanes IV. In this work, via the composite CBS-QB3 study on the isomers and transition states of N3H3—the simplest N3R3 system, we unexpectedly found a new structural type V, which contains a N3 three-membered ring with one nitrogen-nitrogen dative bond in the ring (i.e., cyclic ammonia-nitrene interaction). Of all the N3H3 isomers, V lies the highest in energy (78.7 kcal/mol above the global triazene) and possesses a relatively low conversion barrier 8.9 kcal/mol. Yet quite promisingly, suitably choosing substituents can tune the rate-determining barrier of V to reach around 20 kcal/mol. Thus, synthesis of the newly found triazene isomer V is highly probable.

Using the azo coupling of 3-chloro-2-ethoxiethilaniline for its determination in form of related triazene derivative by method of the high performance liquid chromatography.

Abstract: Triazene 3-chloro2-ethoxiethilaniline (CEA) from 4-nitrophenyldiazonium cations was synthesized. By elemental analysis method, its structure has been confirmed. The effect of hydrogen ions on the formation of CEA azoderivate was studied within the range of 2.8–12.6 pH, the optimum being pH 3.5–5.5. The decrease in the yield of triazene CEA at pH 7 is due to a decrease in the diazonium-cation concentration. The yield of amine triazene also depends on the reaction time, as well as on the excess of the diazo reagent. The effect of the concentration of the reagent on the formation of azoderivate was studied, while the diazonium-cation concentration was varied from 1 to 30 times with respect to the amount of CEA. Azoderate is formed already at the ratio of components 1 : 1 in the amount of almost 50% of the theoretically calculated yield of the substance. With a further increase in the concentration of the diazo reagent by up to an order, the amount of formation of azoderivate sharply increases. At concentrations of more than 10 multiple amounts, almost complete formation of azo condensation is achieved. In further studies, its 20 times excess was used. To extract and recover the azoderivate, a number of organic solvents were examined: hexane, toluene, o-xylene, dichloromethane, chloroform, dichloroethane, ethyl acetate, butyl acetate, isoamyl acetate. The best were dichloromethane and chloroform. For practical purposes, chloroform was subsequently used. The kinetics of the formation of azoderivate was studied. Already in the first minutes of the solution exposure, almost half of the theoretically calculated yield of triazene is formed and increases significantly over a period of up to 40 minutes exposure of solutions. With an increase in the interaction time of the components to 40–100 min, the yield of azoderevate increases insignificantly. Optimum is 60 minutes exposure of solutions. A linear dependence of the area of chromatographic peaks on the concentration of CEA is observed in the range 22–4,300 μg/dm3. Based on the data obtained, a methodology for determining CEA in wastewater and soils has been developed.

Novel photolytic triazene polymer

Abstract: The invention belongs to the technical field of the laser-induced forward transfer, and particularly relates to a novel photolytic triazene polymer. The provided triazene polymer has the novel structure, and is photolytic. The light absorption peak wave length thereof is more than 380 nm. The damage to cells caused by an ultraviolet source can be effectively avoided, and the potential requirement of applying the laser-induced forward transfer technology to the biomedical science experimental research can be satisfied. In addition, the triazene polymer has high purity and good solubility, can be decomposed into small pieces during the photolysis process, and decomposed into a gaseous product in the melting plume. The cellular layer cannot be polluted, and a solid melting product kept on the surface of the cellular layer can be taken away. An additional cleaning step is not needed.

Synthesis and characterization of Bis (3-hydroxy-3-phenyl-1-O-carboxyphenyl triazene) Manganese (II) complex

Abstract: 3-hydroxy-3-phenyl-1-o-Carboxyphenyltriazene (HT) was synthesized by coupling ethanolic solution of diazonium salt of 2-aminobenzoic acid with phenylhydroxylamine in 1:1 molar proportion at 0-5 O C in a refrigerator. Interaction of ethanolic solution of the ligand and aqueous solution of Manganese (II) sulphate heptahydrate formed bis (3-hydroxy-3-phenyl-1-o-carboxyphenyltriazene) Manganese (II) monohydrate. The ligand is soluble in many organic solvents; however, it is slightly soluble in water. Similarly the Manganese (II) complex is soluble in some organic solvents and water. The molar conductance of the complex is 36.7 Ohm -1 Cm 2 Mol -1 which is quite low, suggesting that the compound is non-electrolyte. The complex compound decomposed at 208 O C, indicating good thermal stability. The infrared of the ligand and the complex showed bands, which are attributable to ʋ (N=N) stretching vibration at 1397 and 1400 Cm -1s . The bands at 3425 and 3463 Cm -1 are assigned to ʋ (O-H) vibration in the complex and the ligand respectively. The empirical formular calculation from gravimetric analysis results revealed a 1: 2 metal to ligand ratio. Keywords: Schiff base complex, 3-hydroxy 3- phenyl-1-o-carboxyphenyltriazene

Organic Synthesis Reaction Involved by Aryl-Triazene As an Arylation Reagent

Abstract: The aryl-triazene, as an extremely useful and versatile organic synthesis midbody, can be extracted from the aromatic amines in a simple way. This paper mainly describes the arylation reaction between palladium catalysis aryl-triazene and indole and azole compounds; the cyclization reaction between rhodium catalysis aryl-triazene and N-methoxybenzamide; while we also design a cross-coupling reaction of palladium catalysis aryl-triazene with indole, and filter catalysts, solvents and additives to contribute the best experiment conditions and a good harvest in the end. The results deduced in the paper show that aryl-triazene attributes to a useful organic synthesis midbody which actively involves in coupled reaction with indole-2.

The synthetic potential and the biological action of 1(2)-amino-9,10-anthracenediones and their functional derivatives

Abstract: The review has systematized the literature data of the structural modification methods for 1(2)-amino-9,10-anthracenedione derivatives with alkyl, aryl, acyl, sulfur- and nitrogen-containing acyclic and heterocyclic condensed and non-condensing fragments; the results of the experimental studies of the biological activity of this class of compounds have been analyzed. The conditions of alkylation and arylation of the amino group of amino-9,10-anthracenediones are presented. The methods of acylfunctionalization of aminoanthracenediones have been analyzed. The use of bifunctional chloroanhydrides in obtaining various acyclic and heterocyclic derivatives has been shown. The synthetic potential of the dediazonization reaction has been discovered in production of a wide class of derivatives. Much attention has been paid to production of heterocyclic annelated (imidazole, oxazole, thiazole, azine, phenothiazine, pyrazole, phenanthroline, quinoline) and nonannelated (triazene, furane, pyridine, acridine, thiophene, pyrolytic, triazine, quinoxaline, thiazole) derivatives. In addition, the modification of the amino group has been clarified using aryliso(thio)cyanates, and the use of benzoyl isothiocyanates in the synthesis of thiazole, triazole and tetrazole derivatives has been demonstrated. The review shows that compounds of this type have different types of the biological activity. In particular, they are characterized by the antitumor, antiviral, antimicrobial, antifungal, antioxidant, antithrombotic activities.

Triazene mixture and preparation method thereof

Abstract: The application belongs to the technical field of laser-induced forward transfer (LIFT) and in particular relates to a triazene mixture and a preparation method thereof. The triazene mixture provided by the invention is prepared from triazene and polydimethylsiloxane; the triazene mixture is easy to form on an interface of air; a preparation process of a LIFT source part is simplified; the shape accuracy of material deposition is improved; the requirements of a LIFT technology on forming of a sacrificial layer when a complex shape is deposited can be met; application of the LIFT technology to scientific experimental research of biomedicine is promoted.