Synthesis and characterization of new blue‐greenish electroluminescent materials based on 1,3,4‐oxadiazole‐triazolopyridinone hybrids

New functionalized oxadiazole‐triazolopyridinone derivatives were synthesized via arcycloaddition. With the chromophores of triazolopyridinone, the photoluminescence spectra of these compounds in dichloromethane solution showed emission peaks between 430 and 520 nm. Following the spectroscopic studies, and the measurements of cyclic voltammogram, 1,3,4‐oxadiazole‐triazolopyridinone hybrids possess a great potential as highly efficient, blue‐greenish, organic light‐emitting devices materials. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:212–219, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20285     

Synthesis and characterization of 1,3,4‐oxadiazole‐triazolopyridinone hybrid derivatives as new blue‐greenish photoluminescent materials

Recently, New functionalized oxadiazole‐triazolopyridinone hybrid compounds were investigated as photoluminescent materials. In this work, we introduce triazolopyridinone to synthesize a series of oxadiazole‐triazolopyridinone hybrid derivatives as potential photoluminescent materials and explore the effect of modification of the triazolopyridinone moiety. The λ_max values of the photoluminescence (PL) spectra of 1,3,4‐oxadiazole‐triazolopyridinone hybrids are promoted to longer wavelengths (470‐486 nm) than the traditional 1,2,3‐triazole derivatives (410‐425 nm) in solutions. PL spectra 5a, 5d , and 5g of the vacuum evaporated films on quartz substrates, with a maximum at 487 nm, shows a red‐shift (～15‐20 nm), with respect to the solution spectrum. The solution fluorescence quantum yields (Φ_f) were measured, all of which fell into the range 0.65‐0.76, and were determined relative to that of 2‐phenyl‐5‐(4‐biphenyl)‐1,3,4‐oxadiazole in benzene (Φ_f = 0.80). 1,3,4‐Oxadiazole‐triazolopyridinone hybrid derivatives show clearly non‐reversible reduction processes in cyclic voltammogram measurements. Following spectroscopic studies and observation of the electrochemical behaviors, 1,3,4‐oxadiazole‐triazolopyridinone derivatives were determined to be potential efficient bluegreenish photoluminescent materials.     

Synthesis and electroluminescent properties of a novel 1,3,4‐oxadiazole‐containing polymer

The new blue light polymer, poly(1′,4′‐phenylene‐1″,4″‐[2″‐(2″″‐ethylhexyloxy)]phenylene‐1‴,4‴‐phenylene‐2,5‐oxadiazolyl) (PPEPPO) was synthesized through the Suzuki reaction of diboronic acid, 2‐methoxy‐[5‐(2′‐ethylhexyl)oxy]‐1,4‐benzene diboronic acid (MEHBBA) and dibromide, 2,5‐bis(4′‐bromophenyl)‐1,3,4‐oxadiazole. This polymer was characterized with various spectroscopic methods. The solid PL spectrum of PPEPPO has a maximum peak at 444 nm corresponding to blue light. Blue LED has been fabricated using this polymer as the electroluminescent layer, ITO as the anode, and aluminum as cathode. This device emitted a blue light, with 40 V of turn‐on voltage. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3086–3091, 2000     

Synthesis of ribosylated 1,2,3‐triazole derivatives

Ribosylated 1,2,3‐triazole 4 and 5 were synthesized in moderate yields by the reaction of aroyl‐substituted heterocyclic ketene aminals 1 or 2 with 2,3,5‐tri‐O‐benzoyl‐β‐D ‐ribofuranosyl azide ( 3 ). Their structures were determined by elemental analyses and spectroscopic methods. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:487–490, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10167     

New synthesis of highly potential efficient bluish‐green electroluminescent materials based on 1,3,4‐oxadiazole–triazolopyridinone–carbazole derivatives for single‐layer devices

New potential bluish‐green electroluminescent materials of 1,3,4‐oxadiazole–triazolopyridin‐ one–carbazole derivatives were synthesized and characterized for single‐layer devices. Carbazole, pyridine, and triazolopyridinone were completely introduced into 1,3,4‐oxadiazole skeletal to play assistant roles in controlling fundamental photolytic process due to the electron‐donating nature, excellent photoconductivity, and flexible structure properties. Following the spectroscopic studies and the measurements of cyclic voltammogram, 1,3,4‐oxadiazole–triazolopyridinone–carbazole derivatives were highly efficient bluish‐green electroluminescent materials. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:160–165, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20201     

Synthesis,structures, and biological activities of new 1H‐1,2,4‐triazole derivatives containing pyridine unit

Fourteen new 1H‐1,2,4‐triazole derivatives containing pyridine moiety were synthesized by condensation of 1‐(pyridine‐3‐yl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone with aryl aldehydes, and their reaction conditions were studied. The title compounds were screened for their antibacterial and plant growth regulatory activities. The screening data revealed that most of the compounds showed some antifungal and plant growth regulatory activities. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:376–380, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20308     

NMR spectroscopic characterization of new 2,3‐dihydro‐1,3,4‐thiadiazole derivatives

The ¹H and ¹³C NMR resonances of twenty‐seven 2,2‐dimethyl‐5‐(2‐nitrophenyl‐5‐substituted)‐2,3‐dihydro‐1,3,4‐thiadiazoles, and twenty‐seven 3‐acyl‐5‐(2‐amino‐5‐substituted)‐2,2‐dimethyl‐2,3‐dihydro‐1,3,4‐thiadiazoles were assigned completely using the concerted application of one‐dimensional and two‐dimensional experiments (DEPT, HMQC and HMBC). NOESY experiments, X‐ray crystallography and conformational analysis confirm the preferred conformation of these compounds. Copyright © 2012 John Wiley & Sons, Ltd.     

Acid Catalyzed tert‐Butylation and Tritylation of 4‐Nitro‐1,2,3‐triazole: Selective Synthesis of 1‐Methyl‐5‐nitro‐1,2,3‐triazole via 1‐tert‐Butyl‐4‐nitro‐1,2,3‐triazole

4‐Nitro‐1,2,3‐triazole was found to react with tert‐butanol in concentrated sulfuric acid to yield 1‐tert‐butyl‐4‐nitro‐1,2,3‐triazole as the only reaction product, whereas tert‐butylation and tritylation of 4‐nitro‐1,2,3‐triazole in presence of catalytic amount of sulfuric acid in benzene was found to provide mixtures of isomeric 1‐ and 2‐alkyl‐4‐nitro‐1,2,3‐triazoles with predominance of N2‐alkylated products. A new methodology for preparation of 1‐alkyl‐5‐nitro‐1,2,3‐triazoles from 1‐tert‐butyl‐4‐nitro‐1,2,3‐triazole via exhaustive alkylation followed by removal of tert‐butyl group from intermediate triazolium salts was demonstrated by the example of preparation of 1‐methyl‐5‐nitro‐1,2,3‐triazole.     

Preparation and characterization of 1,2,3‐triazole‐cured polymers from endcapped azides and alkynes

Fourteen commercial polyols have been characterized by GPC, NMR spectroscopy, and elemental analysis. From these, eight corresponding tosylates, six nitrate esters, seven mesylates, 13 alkynes, and 14 azides have been prepared and all these derivatives have been fully characterized. Five alkyne monomers and eight azide monomers were also prepared. Twelve alkynes and 13 azides (functionality 2–4) were combined in 1,3‐dipolar cycloaddition reactions under neat conditions to prepare triazole‐cured polymers, avoiding any heavy metal catalyst. Characterization by NMR spectroscopy, elemental analysis, and gel permeation chromatography indicated triazole polymers 14 , 22 , 23 , 28 , and 30 with degrees of polymerization of 17–28 to be the best candidates for future work. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 238–256, 2008     

Synthesis of Boltorn 1,2,3‐triazole dendrimers by click chemistry

Second‐, third‐, and fourth‐generation hyperbranched aliphatic polyols namely Boltorn® H20, Boltorn H30, and Boltorn H40 were endcapped with azido and activated acetylenic groups in good to excellent yields (75–95%) following an acid catalyzed procedure. The resultant terminally functionalized dendritic azido and acetylenic groups undergo 1,3‐dipolar cycloaddition using methyl (or ethyl) propiolate and benzyl azide, respectively, under catalytic or noncatalytic conditions below 40 °C to yield 1,2,3‐triazole dendrimeric polymers in 82–95% yield, under extremely mild conditions that could be applied for compounds sensitive to acid, base, or heat. The dendritic azido and activated acetylenic derivatives may act as novel scaffolds to tune the mechanical properties of different polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3748–3756, 2009     

Synthesis and antimicrobial and pharmacological properties of new thiosemicarbazide and 1,2,4‐triazole derivatives

Reaction of 4‐phenyl‐4H‐1,2,4‐triazole‐3‐thione with ethyl bromoacetate has led to the formation of ethyl [(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)sulfanyl]acetate 1 , the structure of which was confirmed by X‐ray analysis. In the next reaction with 80% hydrazide hydrate, appropriate hydrazide 2 was obtained, which in reaction with isothiocyanates was converted to new acyl derivatives of thiosemicarbazides 2 , 3 , 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h . The cyclization of these compounds in alkaline media has led to formation of new derivatives of 5‐{[(4‐phenyl‐4H‐1,2,4‐triazole‐3‐yl)sulfanyl]methyl}‐4H‐1,2,4‐triazole‐3(2H)‐thiones 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4j . The structure of the compounds was confirmed by elementary analysis and IR, ¹H‐NMR, ¹³C‐NMR, and MS spectra. Compounds 2 , 3 , 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h and 4a , 4b , 4c , 4d , 4e , 4f , 4g were screened for their antimicrobial activities, and the influence of the compounds 4a , 4b , and 4e , 4f , 4g on the central nervous system of mice in behavioral tests was examined. J. Heterocyclic Chem., (2011).     

Synthesis and antimicrobial evaluation of some 1,2,4‐triazole, 1,3,4‐oxa(thia)diazole,and 1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazine derivatives

3‐Methyl‐2‐benzofurancarboxylic acid hydrazide ( 2 ) reacts with carbon disulfide and pota‐ ssium hydroxide to give the corresponding potassium carbodithioate salt 3 . Treatment of the latter salt with hydrochloric acid, hydrazine hydrate, and with phen‐ acyl bromide afforded the corresponding 1,3,4‐oxadia‐ zole‐5‐thione 4 , 4‐amino‐1,2,4‐triazole‐5‐thione 5 , and thiazolidine‐2‐thione 9 derivatives, respectively. The reaction of either 1,3,4‐oxadiazole‐5‐thione 4 or 4‐amino‐1,2,4‐triazole‐5‐thione 5 with phenacyl bromide resulted in the formation of 1,2,4‐triazolo[3, 4‐b]‐1,3,4‐thiadiazine derivative 8 . Treatment of compounds 3 or 4 with hydrazonoyl halides 10a–d furn‐ ished the same 1,3,4‐thiadiazol‐2‐ylidene derivatives 11a–d . The 7‐arylhydrazono‐1,2,4‐triazolo[3,4‐ b ]‐1, 3,4‐thiadiazine derivatives 12a–d were obtained either by treatment of 4‐amino‐1,2,4‐triazole‐5‐thione 5 with hydrazonoyl halides 10a–d or by coupling of the 1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazine derivative 8 with diazonium salts. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:621–627, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20162     

Synthesis of new heterocyclic compounds having 1,2,3‐triazole and isoxazole rings in a single molecule

Five series of new heterocyclic compounds of 1,2,4‐triazole Mannich bases, 1,3,4‐oxadiazole Mannich bases, 1,3,4‐oxadiazolines, 1,2,4‐triazolo[3,4‐b]1,3,4‐thiadiazines and 1,2,4‐triazolo[3,4‐b]1,3,4‐thiadiazoles, in which 1,2,3‐triazolyl and isoxazolyl have been united, were synthesized from the intermediate of 5‐methyl‐3‐(2‐phenyl‐2H‐1,2,3‐triazol‐4‐yl)isoxazole‐4‐carbohydrazide, Their structures were established by spectroscopy.     

Synthesis and antimycobacterial activity of alkyl 1‐heteroaryl‐1H‐1,2,3‐triazole‐4‐carboxylates

A series of alkyl l‐heteroaryl‐1H‐1,2,3‐triazole‐4‐carboxylates 6a‐u were synthesised in four steps from methyl (Z)‐2‐benzyloxycarbonylarmino‐3‐(dimethylamino)prop‐2‐enoate ( 1 ) and heterocyclic amines 2a‐s. Triazoles 6a‐o were tested against antimycobacterial activity. For the most active compound, n‐pentyl 1‐(6‐phenylpyridazin‐3‐yl)‐1H‐1,2,3‐triazole‐4‐carboxylate ( 6n ), minimum inhibitory concentration 3.13 μg/ml was determined.     

Synthesis and properties of novel polytriazoleimides derived from 1,2,3‐triazole‐containing diamines and aromatic dianhydrides

A new kind of 1,2,3‐triazole‐containing aromatic diamines were synthesized by the Cu(I)‐catalyzed 1,3‐dipolar cycloaddition reaction. These diamines were employed to synthesize a series of novel polytriazoleimides (PTAIs) by polycondensation with various aromatic dianhydrides in N,N‐dimethylacetamide (DMAc) via the conventional two‐step method. The obtained polyimides were characterized by Fourier transform infrared, hydrogen‐1 nuclear magnetic resonance, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis techniques. The results show that the PTAIs are soluble in most of strong polar solvents and have inherent viscosity values of 0.47–0.68 dl/g (DMAc). PTAI films have tensile strengths of 60.6–102.6 MPa and elongations at breakage of 3.0–4.1%, glass transition temperatures (T_g) of 208–262°C, and decomposition temperatures (at 5% weight loss) of 368–401°C in N₂ atmosphere, which depend on the structure of the polymers. The PTAIs also exhibit good adhesion to copper and gas separation properties. Copyright © 2011 John Wiley & Sons, Ltd.     

Acid‐mediated regioselective alkylation of 1,2,3‐triazole

1,2,3‐Triazole reacts with isopropyl alcohol in concentrated sulfuric acid to yield 1‐isopropyl‐1H‐1,2,3‐triazole as the only reaction product.     

Synthesis and antimicrobial activity of some heterocyclic 2,6‐bis(substituted)‐1,3,4‐thiadiazolo‐, oxadiazolo‐, and oxathiazolidino‐pyridine derivatives from 2,6‐pyridine dicarboxylic acid dihydrazide

In this work, we report on the synthesis and preliminary biological activity screening of several heterocyclic derivatives 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 10a , 10b , 11 , 11a , 11b , 12 , 12a , 12b , 13 , 13a , 13b , 14 , 15 based on N2′,N6′‐diphenylthiosemi‐carbazide pyridine‐2,6‐dicarbohydrazide 2 , which has been obtained from the corresponding dihydrazide 1 . The biological screening showed that many of these compounds have good antimicrobial activities. The structure of the new compounds has been established on the bases of chemical and spectroscopic evidences. J. Heterocyclic Chem., (2011).     

Synthesis of 2(5H)‐Furanone Derivatives with Bis‐1,2,3‐triazole Structure

A series of new chiral 2(5H)‐furanone derivatives containing bis‐1,2,3‐triazole moiety were designed and synthesized from (5S)‐5‐alkoxy‐3,4‐dihalo‐2(5H)‐furanones 1 , dicarboxyl amino acids 2 , propargyl bromide, and organic azides 5 under mild conditions via the sequential three steps, including asymmetric Michael addition‐elimination, substitution and no‐ligand click reaction. Twelve new intermediates, including N‐[5‐alkoxy‐2(5H)‐furanonyl] dicarboxyl amino acids 3 and their corresponding propargyl esters 4 , and twelve target molecules 6 were characterized by FTIR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The influences of different synthetic conditions and substrates in each step were investigated. The research provides a new method and idea for the synthesis of 2(5H)‐furanone compounds with polyheterocyclic structure due to the diversities of four basic unit molecules.