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Showing papers on "Triazene published in 2010"


Journal ArticleDOI
TL;DR: Silyl-substituted NHC 2 reacts easily with 1-azidoadamantane to form triazene 3, in which the exocyclic C=N bond is slightly shorter than those of regular NHC-derived triazines.
Abstract: Reaction of IPr x SiCl(2) (1) [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] with 1-azidoadamantane leads to functionalized N-heterocyclic carbene (NHC) 2. Silyl-substituted NHC 2 reacts easily with 1-azidoadamantane to form triazene 3, in which the exocyclic C=N bond is slightly shorter than those of regular NHC-derived triazines. 2 could serve as a promising ligand for transition metals.

55 citations


Journal ArticleDOI
TL;DR: In this article, triazenes are used as masked diazonium ions to improve the chemoselectivity of the Richter cyclization of 4-halocinnoline and 4-cinnolinone products.

42 citations


Journal ArticleDOI
TL;DR: The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and it is expected that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the prepared of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3-triazoles derivatives.
Abstract: We report the copper(II)-catalyzed conversion of organoboron compounds into the corresponding azide derivatives. A systematic series of phenylboronic acid derivatives is evaluated to examine the importance of steric and electronic effects of the substituents on reaction yield as well as functional group compatibility. Heterocyclic substrates are also shown to participate in this mild reaction while compounds incorporating B-C(sp(3)) bonds are unreactive under the reaction conditions. The copper(II)-catalyzed boronic acid-azide coupling reaction is further extended to both boronate esters and potassium organotrifluoroborate salts. The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and we expect that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the preparation of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3-triazoles derivatives.

40 citations


Journal ArticleDOI
TL;DR: Electrochemical studies demonstrated that grafting through the triazene modifier can successfully compete with existing protocols for DNA immobilization through the commonly used alkanethiol linkers and diazonium salts.
Abstract: A new DNA modifier containing triazene, ferrocene, and activated ester functionalities was synthesized and applied for electrochemical grafting and characterization of DNA at glassy carbon (GC) and gold electrodes. The modifier was synthesized from ferrocenecarboxylic acid by attaching a phenyltriazene derivative to one of the ferrocene Cp rings, while the other Cp ring containing the carboxylic acid was converted to an activated ester. The modifier was conjugated to an amine-modified DNA sequence. For immobilization of the conjugate at Au or GC electrodes, the triazene was activated by dimethyl sulfate for release of the diazonium salt. The salt was reductively converted to the aryl radical which was readily immobilized at the surface. DNA grafted onto electrodes exhibited remarkable hybridization properties, as detected through a reversible shift in the redox potential of the Fc redox label upon repeated hybridization/denaturation procedures with a complementary target DNA sequence. By using a methylene...

37 citations


Journal ArticleDOI
TL;DR: In this article, the triazenide complexes were studied as catalysts in the hydrogenation of 2-cyclohexen-1-one and cinnamaldehyde.

29 citations


Journal ArticleDOI
TL;DR: The reaction of methyl anthranilate, sodium nitrite, and 2-aminobenzothiazole produces a new triazenide, namely, 1-[(2-carboxymethyl) benzene]-3-[benzothiazoles]triazene (HL), which has been characterized by X-ray crystallography, cyclic voltammogram and emission spectrum.

26 citations


Journal ArticleDOI
TL;DR: In this paper, a new optical sensor for highly sensitive and selective determination of mercury(II) ion in aqueous solutions is developed, which has a relatively fast response time of less than 5 min.

24 citations


Journal ArticleDOI
TL;DR: In this paper, aldols were obtained with moderate to good yields and enantioselectivities (44-86% ee) with LDA or chiral lithium amides, and resulting lithium enolates were trapped with an aldehyde.
Abstract: Polymer-anchored (Merrifield, trityl chloride, Wang p-nitrophenyl carbonate and triazene supports) nortropinone, or N-protected nortropinone derivatives in solution, were subjected to deprotonation with LDA or chiral lithium amides, and the resulting lithium enolates were trapped with an aldehyde. The aldols were obtained with moderate to good yields (44-84%) and enantioselectivities (44-86% ee).

13 citations


Journal ArticleDOI
TL;DR: A series of 1,4-di-[2-aryl-1-diazenyl]-2-methylpiperazines (4a-n) have been synthesized by the reaction of 2-methyl piperazine with 2 equiv. of the appropriate diazonium salt as mentioned in this paper.
Abstract: A series of 1,4-di-[2-aryl-1-diazenyl]-2-methylpiperazines (4a–n) have been synthesized by the reaction of 2-methylpiperazine with 2 equiv. of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by HR-EIMS, with accurate mass measurement of the molecular ion. The presence of a chiral centre at C2 of the piperazine ring in the bistriazene 4 creates a multitude of diastereotopic protons in the methylene groups of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in some cases, such as the tolyl- (4h) and phenyl- (4j) derivatives. These two compounds also show a discrimination between the two N-arydiazenyl groups, as evidenced by the doubling of several aromatic-carbon signals in the 13C NMR spectra. The assignment of the proton and carbon signals in 4h and 4j has been aided by the use of 2D NMR spectroscopy. A DEPT spectrum of 4j clearly discriminates th...

12 citations


Journal ArticleDOI
TL;DR: In this paper, the synthesis, characterization and crystal structures of three new copper complexes derived from 1,3-bis(aryl)triazenido ligands bearing either a methoxy carbonyl, methylthio or a hydroxymethyl group in the ortho position of one of the aromatic rings are reported.

11 citations


Journal ArticleDOI
TL;DR: In this article, 5-Azidotriazoles bearing a thiazole, benzothiazole or pyridine ring at the 4 position were synthesized and thermolyzed at 60°C.
Abstract: 5-Azidotriazoles bearing a thiazole, benzothiazole or pyridine ring at the 4-position were synthesized and thermolyzed at 60°C. Whereas the 5-azido-4-(thiazol-2-yl)triazole 4 decomposed with extrusion of nitrogen and formation of the triazene 5 as the sole reaction product, the 5-azido-4-(benzothiazol-2-yl)triazoles 11a,b furnished mixtures of the triazenes 12a,b and the tetrazoles 14a,b. In the case of the 5-azido-4-(2-pyridyl)triazoles 17a-d, the product distribution was found to depend strongly on the N-1 aryl substituent, favouring the tetrazole 20 by increasing the electron-withdrawing capacity of this group.

Proceedings ArticleDOI
18 Oct 2010
TL;DR: In this paper, a short review of the use of triazene polymer as a dynamic release layer (DRL) for laser-induced forward transfer (LIFT), before looking at the latest research in more detail is presented.
Abstract: This article presents a short review of the use of triazene polymer as a dynamic release layer (DRL) for laser-induced forward transfer (LIFT), before looking at the latest research in more detail. The field of triazene polymer ablation only started around 20 years ago and has grown rapidly into a number of different application areas. Most promisingly, triazene ablation has been refined as a method for propulsion, bringing the benefits of LIFT to the deposition of sensitive transfer materials. The key to understanding LIFT with a triazene DRL is to understand the more fundamental nature of triazene polymer ablation in both frontside and backside orientations. This article focuses on the most recent experimental results on LIFT with a triazene DRL: the effect of picosecond pulse lengths compared with nanosecond pulse lengths; the effect of reduced air pressure; and the improvements in transfer in terms of range of transfer materials, and transfer across a gap. The results all help improve fundamental understanding of triazene-based LIFT, and the transfer of functioning OLEDs demonstrates the capability of the technique.

Journal ArticleDOI
TL;DR: A novel method for preparation of N-methylated tertiary amines, including tropanes, based on quaternization and nucleophilic debenzylation of so formed ammonium salts immobilized via benzyl amine linkage on a widely available solid support, the Wang gel is described.
Abstract: Synthesis on solid phase is one of modern methodologies especially useful in parallel and combinatorial syntheses. Tertiary amine functionalities are found in many important classes of catalysts, reagents and biologically active compounds. The tertiary N-methyl group is also present in structures of tropane alkaloids and majority of synthetic tropane derivatives with potential biological activity. Despite of well-defined tropane scaffold structure, which is present in known or potentially bioactive functionalized tropane derivatives only a few approaches to tropanes libraries and supported synthesis have been studied. Our approach to supported synthesis of tropane derivatives is based on anchoring nortropinone (1, Scheme 1), a secondary amine which naturally required a postcleavage N-methylation with one of the known procedures. Although secondary amines can be anchored reversibly via several well-known linkers including activated Wang carbonate, and triazene T2, we also looked for other methods. The linkers preserving the amine character of the anchored nitrogen atom, such as REM (via Michael addition-Hofmann elimination), amino acetals (DSEM and POEM), BAL-type, BOBA and several widely available polymeric gels (Merrifield, trityl chloride), could offer certain advantages. The motivation for seeking such anchors was an observation that the reactions of lithium enolates of tropinone and N-benzylnortropinone (both tertiary amines) in solution were more stereoselective and higher yielding than reactions of corresponding N-diazaphenyl (triazene) or carbobenzyloxy (uretane) derivatives. Therefore, we undertook a study on anchoring, and cleavage of nortopinone (1) on various polymeric supports with emphasis on methods for conversion of immobilized nortropane scaffold to tertiary amines such as tropane (2, Scheme 1). Solid-phase methods for synthesis of tertiary amines including N-methyl amines have been reported by Andersson. Others reported solid-phase alkylation and cleavage of tertiary amines by Hofmann type elimination from REM-type resins. An interesting method for debenzylating cleavage of quaternized amines from the Merrifield support based on nucleophilic displacement was reported by Cai. In our report, we wish to describe a novel method for preparation of N-methylated tertiary amines, including tropanes, based on quaternization and nucleophilic debenzylation of so formed ammonium salts immobilized via benzyl amine linkage on a widely available solid support, the Wang gel. We also report results of our approaches to reversible immobilization of nortropinone on polystyrene type supports with MOM analogue, BOM analogue, Wang type, PAL-type, Merrifield, para-C3-T2 triazene, carbamate Wang, and trityl linkers (Figure 1). Reversible Anchoring of the Amino Ketone. The cyclic secondary amines like nortropinone (1) could, in principle, be immobilized in a form of a tertiary amine via several linkers such as REM, Wang, and BAL linkers. The REM linker could not be used for our purposes because of its incompatibility with the basic conditions of enolate reactions, such as the directed aldol reaction. The Wang and BAL type linkers are typically used for releasing amine derivatives, usually amides or sulfonamides. However, the recent reports prompted us to investigate their use for immobilization of amino ketones such as nortropinone. We found that even though nortropinone could be anchored to Wang polymer (to give 6) and the 2,6-dimethoxy Wang polymer (to give 10, PAL type linker) very effectively (87-100%, Table 1, Figure 1), cleavage of this amino ketone was not feasible. Attempted oxidative cleavage of the Wang linker 6 (with DDQ) and simple benzylamine linker 7 derived from Merrifield polymer (with ceric(IV) ammonium nitrate, CAN), in our hands, did not provide any amine products (Figure 1). Therefore, we investigated amino acetal linkers analogous to MOM and BOM protecting groups for amines (8 and 9, Figure 1). Preparation of similar linkers by two different methods was reported. Unfortunately, we were able to obtain only modest loadings of the test amine, 4-benzylpiperidine or nortropinone 1, via such linkers prepared by either method (Figure 1). The cleavage provided poor loadings of released amines (17 and 9%, Table 1) despite using trifluoroacetic acid (TFA) at different concentrations, addition of water, prolonged cleavage times, and ultrasound. The only practical method for reversible linking of the amino ketone 1 to polymers in the form of a tertiary amine was the reactions with Merrifield gel or trityl chloride gel to form loaded polymers 7 and 3, respectively (Figure 1). The amino ketone could however be cleaved off the Merrifield support only by the procedure of Leysen et al. (action of 1-chloroethyl chloroformate (ACE-Cl) in 1,2dichloropropane (DCP), followed by methanolysis) in an analogy to the known reactions in solution, albeit with moderate yield (37% of the theoretical loading). As expected, nortropinone was very efficiently anchored and cleaved from supports with trityl linker 3 and carbamate Wang linker 4, (ca. 100% of the theoretical loadings). Immobilization and

Journal ArticleDOI
TL;DR: In this paper, the effect of monomer/sodium nitrite ratio on the solubility of the polymers, as well as the dependence of properties such as electrical conductivity and ESR upon the main chain structure, have been investigated.


Journal ArticleDOI
TL;DR: A computational study of a series of model triazene-based anticancer agents based on methyl and amidyl-substituted 5-(1-triazenyl)imidazoles has been carried out, including the drugs Dacarbazine,...
Abstract: A computational study of a series of model triazene-based anticancer agents based on methyl- and amidyl-substituted 5-(1-triazenyl)imidazoles has been carried out, including the drugs Dacarbazine, ...

Journal ArticleDOI
TL;DR: In the presence of Et3N, the reaction of HL and CuCl2·2H2O gives a μ4-oxo-bridged tetranuclear copper(II) complex [Cu4OL3Cl3]·1.5THF (1· 1.5thF), which has been characterized by X-ray crystallography and magnetic susceptibility measurements as mentioned in this paper.
Abstract: The reaction of methyl anthranilate, sodium nitrite, and 2-aminopyridine produces a triazenide, namely, 1-[(2-carboxymethyl)benzene]-3-[2-pyridine]triazene (HL). In the presence of Et3N, the reaction of HL and CuCl2·2H2O gives a μ4-oxo-bridged tetranuclear copper(II) complex [Cu4OL3Cl3]·1.5THF (1·1.5THF), which has been characterized by X-ray crystallography and magnetic susceptibility measurements.

Journal ArticleDOI
TL;DR: In this paper, the Sandmeyer reaction was used to convert triazenyl triazenes to substituted anilines by reduction or to novel substituted aromatics by a modified sandmeyer reaction.
Abstract: Reaction of (2-, (3-, and (4-bromophenyl)-3,3-(1,4-butanediyl)triazenes (derived from the corresponding 2-, 3-, and 4-bromoanilines) with sec- or tert-butyllithiums gave the corresponding (triazenylaryl)lithiums; these intermediates reacted with a variety of electrophiles to give substituted aryl triazenes. These products cound be converted to substituted anilines by reduction or to novel substituted aromatics by a modified Sandmeyer reaction

Journal ArticleDOI
TL;DR: The crystal structure of the title compound, (C6F5)2N3H, is stabilized by N—H⋯N hydrogen bonding, forming centrosymmetric dimers organized in a herringbone motif, resulting in higher precision for the C—C bond lengths.
Abstract: The crystal structure of the title compound, (C6F5)2N3H, is stabilized by N—H⋯N hydrogen bonding, forming centrosymmetric dimers organized in a herringbone motif. Important geometrical parameters are N—N = 1.272 (2) and 1.330 (2) A and N—N—N = 112.56 (15)°. The dihedral angle between C6F5 groups is 21.22 (9)°. The room temperature structure was reported by Leman et al. (1993). Inorg. Chem. 32, 4324–4336]. In the current determination, the data were collected to a higher θ angle, resulting in higher precision for the C—C bond lengths(0.001–0.005 versus 0.003 A).

Patent
22 Mar 2010
TL;DR: In this paper, a manufacturing method of carbon nitride with high crystallinity and high hydrogen storage capacity is presented, which includes the following steps: manufacturing dihalogen triazene intermediate by reacting a triazine group compound and halogenated triazine in 0°C or less.
Abstract: PURPOSE: Carbon nitride with high crystallinity and high hydrogen storage capacity, a manufacturing method thereof, and a hydrogen storage material using the same are provided to synthesize the carbon nitride at a low temperature without using a metallic catalyst. CONSTITUTION: A manufacturing method of carbon nitride with high crystallinity and high hydrogen storage capacity includes the following steps: manufacturing dihalogen triazene intermediate by reacting a triazine group compound and halogenated triazine in 0°C or less; manufacturing monohalogenation triazene intermediate and dihalogen triazene intermediate in 0~100 °C; and heat-treating monohalogenation triazene intermediate at a temperature of 100~150 °C.

Patent
23 Jun 2010
Abstract: The invention relates to a triazene compound 1-(8-quinoline)-3-(2-pyridyl)-triazene (QPyT) which contains heterocycle. The preparation method of the invention comprises the steps: diazotizing 8-amino quinoline by using sodium nitrate under acidic condition and reacting with 2-aminopyridine in alcoholic solution. The compound is not only a good visualization reagent, but also a fluorescent reagentwith high sensitivity and good selectivity, which can be used for fluoroscopic examination of metal ion, in particular for the examination of Pb (II) in alkaline medium.

01 Jan 2010
TL;DR: In this article, the authors investigated the effect of extra ligand on the rate of oxidation, nature and percentage yield of products in C2H5OH-CH2Cl2 (1:1) mixed solvent system.
Abstract: Rh(I) complexes of S-triazene were found moderately efficient towards the catalytic oxidation of internal alkenes, terminal alkenes, and alcohol in C2H5OH-CH2Cl2 (1:1) mixed solvent system both under normal and high pressure of molecular oxygen. No diminished catalytic activity was observed even after 6-8 repeated catalytic runs. Effect of extra ligand on the rate of oxidation, nature and percentage yield of products was investigated. On the basis of

01 Jan 2010
TL;DR: In this paper, the UV and IR spectral properties of twenty eight N 3 -(aryl/substituted aryl)-N 1 -oxides are reported, which reveal the intramolecular hydrogen bonded triazene-1-oxide structure of these compounds.
Abstract: The UV and IR spectral studies of twenty eight N 3 -(aryl/substituted aryl)-N 1 - (alkyl/aryl/substituted aryl)-triazene-N 1 -oxides are reported, which reveal the intramolecular hydrogen bonded triazene-1-oxide structure of these compounds.

Journal ArticleDOI
TL;DR: Sunlight irradiation of solid mixed crystals of the photolabile triazene 1-oxides and α- or β-naphthol afford azo dyes.
Abstract: Sunlight irradiation of solid mixed crystals of the photolabile triazene 1-oxides and α- or β-naphthol afford azo dyes.

Journal ArticleDOI
TL;DR: In this article, the photochemical decomposition of substituted triazenes and pentazadienes is investigated in view of their application as promoters in laser-induced polymer ablation, and the influence of substituents on the aryl moiety on the quantum yield is analyzed in terms of a correlation with the calculated N1=N2 bond order.
Abstract: Molecular geometries, electronic transitions, bond orders, and dipole moments are calculated for 19 l-aryl3,3-diethyltriazenes and two 3-alkyl- 1 ,5-diarylpentazadienes, using standard AM1 and PM3 semiempirical methods. Calculated UV spectra compare well with the experimental results, A strong correlation is established between the barrier to internal rotation, AG*, and the N2-N3 bond order. The photochemical decomposition of substituted triazenes and pentazadienes is of interest in view of their application as promoters in laser-induced polymer ablation. Therefore, the photolysis quantum yields at 308 nm are investigated in various solvents. The influence of substituents on the aryl moiety on the quantum yield is analyzed in terms of a correlation with the calculated N1=N2 bond order. The effects of different nitrogen-bound alkyl substituents on the photochemical decomposition behavior can be represented by a similar correlation. Differences between the photolysis behavior of triazene and pentazadiene derivatives are discussed.