Cyclecondensation of 3-amino-1,2,4-triazole with substituted methyl cinnamates

The reaction of 3-amino-1,2,4-triazole ( 1 ) with substituted methyl cinnamates 2a-h leads selectively to the formation of 7-aryl-6,7-dihydro[1,2,4]triazolo[1,5-a]pyrimidin-5(4H)-ones 3a-h . The structure eluci dation of the products is based on ir, ¹H and ¹³C nmr measurements and X-ray diffraction.     

The chameleon-like behaviour of 3-amino-1,2,4-triazole in the Biginelli reaction: unexpected formation of a novel spiroheterocyclic system

A novel Biginelli-like assembly of 3-amino-1,2,4-triazole with methyl acetoacetate and salicylaldehyde has been developed to enable easy access to spiro{[1]benzopyran-2,7′-[1,2,4]triazolo[1,5-a]pyrimidine} compounds as representatives of a new class of spiro-fused heterocycles. A three-component condensation mechanism is proposed and discussed.     

Synthesis of some substituted 1,2,4-triazole and 1,3,4-thiadiazole derivatives

New S-substituted 1,2,4-triazole and 1,3,4-thiadiazole derivatives have been prepared. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1712–1715, November, 2008.     

Synthesis and central nervous system stimulant activity of 5,8-methanoquinazolines fused with 1,2,4-triazole,tetrazoleand 1,2,4-triazine

5,8-Methanoquinazolines fused with 1,2,4-triazole 4–5 , tetrazole 6 , and 1,2,4-triazine 8 were prepared starting from 2-hydrazino-5,8-methanoquinazoline 3 . Compound 3 and 6 showed the most potent central nervous system (CNS) stimulant activities.     

A novel N-N bond cleavage reaction of 4-amino-1,2,4-triazole derivatives

5-Substituted-4-amino-3-thiol-1, 2, 4-triazoles (1a- b) react with orthonitrochloro- benzene or para-nitrochlorobenzene to give N-N bond cleavage products 2a-d, one structure of which (2b) has been unambiguously confirmed by an X-ray structural analysis.     

High-performance liquid chromatographic assay of sulbactam using pre-column reaction with 1,2,4-triazole

A high-performance liquid chromatographic (HPLC) method for the determination of sulbactam in human and rat plasma and urine has been developed. Sulbactam was reacted with 1,2,4-triazole to yield a product having an ultraviolet absorption maximum at 326 nm. The product was separated using reversed-phase HPLC from the regular components of plasma and urine with an ion-pair buffer at 50 degrees C and detected at the ultraviolet maximum. The limits of accurate determination were 0.2 and 1.0 micrograms/ml in plasma and urine, respectively. The coefficients of variation of inter- and intra-assays in human plasma spiked at 4.0 micrograms/ml (n = 5) were 1.02 and 3.05%, respectively. Coexisting cefoperazone, penicillins, or the alkaline degradation product(s) of sulbactam did not interfere in the sulbactam assay. The pharmacokinetic behaviour of sulbactam and cefoperazone coadministered to rats was estimated by moment analysis.     

Unusual reaction of 3-amino-1,2,4-triazole with 1,3-diiodopropan-2-one

3-Amino-1,4-bis(2-oxopropyl)-4H-1,2,4-triazolium triiodide is the product of the reaction of 3-amino-1,2,4-triazole with 1,3-diiodopropan-2-one in acetone in the absence of bases and phase-transfer catalysts. In dimethyl sulfoxide, conversely, a water soluble polyionene consisting of three aminotriazole rings bound by 1,3-dimethylenecarbonyl bridges is formed. The effect of the solvent on the alkylation of 3-amino-1,2,4-triazole with 1,3-diiodopropan-2-one was studied.     

Blue-emitting iridium complexes with substituted 1,2,4-triazole ligands: synthesis, photophysics, and devices

Neutral heteroleptic mononuclear iridium(III) complexes with (2,4-difluoro)phenylpyridine and different pyridine-1,2,4-triazole ligands were synthesized and fully characterized. We investigated the effects of substituents in the 5-position of the triazole ring on the photophysical and electrochemical behavior. Increasing the electron-withdrawing capabilities generally leads to a lowering of the HOMO level with a consequent slight widening of the HOMO-LUMO gap and a blue shift in emission. The complexes reported exhibit high emission quantum yields and long luminescent lifetimes, typical of iridium(III) complexes, and most of them show reversible redox processes in solution. Also, many of the complexes reported here have been obtained as single crystals suitable for X-ray crystallography. Two of the complexes were further tested as phosphorescent dyes in OLED devices and showed high external quantum efficiencies (~7%) and color points better than the "standard" for blue iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C2']picolinate (FIrpic). We also report the full electrochemical investigation of FIrpic in different solvents.     

Novel electrosynthesis of a condensed thioheterocyclic system containing a 1,2,4-triazole ring

An efficient and convenient electrosynthesis of thioheterocyclic compounds 6a-d is described via a one-pot, two-component condensation of triazoles (1a,b) or triazine (1c) with acetylenedicarboxylic acid esters (2a,b).     

Vulnerability of substituted aromatic hydroxy aldehydes to undergo Biginelli reaction in water

Abstract

Aromatic aldehydes having hydroxyl substituent(s) react with urea (or thiourea), and ethyl acetoacetate (or acetylacetone) in the presence of p-toluenesulfonic acid as catalyst and water as solvent to give substituted dihydropyrimidinones (Biginelli compounds) in good to excellent yields.     

A piperidinium triflate catalyzed Biginelli reaction

A piperidinium triflate, 1,1,3,5-tetramethyl-4-oxo-2,6-diphenylpiperidinium triflate, in acetonitrile efficiently catalyzes one synthetic operational construction of biopertinent hydropyrimidines from respective aldehyde, β-dicarbonyl, and urea/thiourea building blocks.     

N-Amination of 3-amino-1,2,4-triazole with hydroxylamine-O-sulfonic acid: Synthesis of 1,5-diamino-1,2,4-triazole

N-Amination of the 3(5)-amino-1,2,4-triazolide anion with hydroxylamine-O-sulfonic acid is studied. This method provided an access to the previously unknown 1,5-diamino-1,2,4-triazole.     

A cis amide bond surrogate incorporating 1,2,4-triazole

A novel cis amide bond surrogate incorporating 1,2,4-triazole was designed and synthesized by the reaction of a thionotripeptide, formic hydrazide, and mercury(II) acetate. This method of surrogate formation was also applicable to a cyclic thionopeptide.     

Study of 6-hydrazinophenathridine in acylation and annelation reactions of the 1,2,4-triazole ring

The reactions of 6-hydrazinophenanthridine with phthaloyl chloride and isocyanates occur at the hydrazo group. Acylation of this hydrazidine by diethyloxalate or oxidation of the hydrazones obtained from it lead to annelated 1,2,4-triazoles. Institute of Technical Chemistry, Urals Branch, Russian Academy of Sciences, Perm' 614000, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 186–189, February, 1998.     

Reactions of 3-azido-1,2,4-triazole with electrophiles

Alkylation of 3-azido-1,2,4-triazole with oxiranes, bromoacetone, and methyl vinyl ketone furnished a mixture of N-substituted 3- and 5-azido-1,2,4-triazoles, 3-azido compounds prevailing. The same substrate subjected to heterylation with 3,5-dinitro-1,2,4-triazole derivatives reacted selectively at the N¹ atom, and its bromination afforded 3-azido-5-bromo-1,2,4-triazole..Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1699–1704.Original Russian Text Copyright © 2004 by Kofman, Krasnov.     

Regioselection in the reaction of 3-amino-5-benzylthio-1,2,4-triazole with unsymmetrical 1,3-diketones

The results of a study of the regioselection in the reaction of 3-amino-5-benzylthio-1,2,4-triazole with several unsymmetrical 1,3-diketones are reported. The 1,3-diketones studied are 1,1,1-trifluoro-2,4-pentanedione, benzoylacetone and 2-acetylcyclopentanone. Chemical, spectroscopic and X-ray crystallographic data are presented to support structural assignments of the major reaction products.     

Comparative theoretical studies on energetic substituted 1,2,4-triazole molecules and their corresponding ionic salts containing 1,2,4-triazole-based cations or anions

We have studied the densities, heats of formation, energetic properties, and thermodynamics of formation for a series of substituted 1,2,4-triazole molecules and their corresponding ionic salts containing 1,2,4-triazolium cations or 1,2,4-triazolide anions using density functional theory and volume-based thermodynamics method. The results show that when the 1,2,4-triazole molecules lose a proton to form corresponding 1,2,4-triazole-based anions, their salts have smaller densities than corresponding molecules. When the molecules get a proton to form the 1,2,4-triazole-based cations, their salts have higher densities than corresponding molecules. The transformation of the 1,2,4-triazole derivatives from nonionic molecules to corresponding cations or anions are very helpful for increasing their heats of formation. Changing the 1,2,4-triazole derivatives into corresponding cations or anions produce different effects on their heats of detonation. Overall, as the compound numbering varies, the evolution trend of heat of detonation is very similar to heat of formation. The salts containing the 1,2,4-triazolide anions have smaller detonation velocities and pressures than corresponding 1,2,4-triazole molecules, whereas the salts containing the 1,2,4-triazolium cations have higher detonation velocities and pressures than corresponding molecules. Finally, the lattice enthalpies and entropies were used to construct a thermodynamic cycle for salt formation to predict the possibility to synthesize the salts.     

Synthesis and screening of some novel substituted indoles contained 1,3,4-oxadiazole and 1,2,4-triazole moiety

A series of novel 3-[5-(1H-indol-3-yl-methyl)-2-oxo-[1,3,4]oxadiazol-3-yl]propionitrile(5),3-[4- amino-3-(1H-indol-3-yl-methyl)-5-oxo-4,5-dihydro-[1,2.4]triazol-1-yljpropionitrile(6),3-[5-(1H- indol-3-yl-methyl)-2-thioxo-[1,3,4]oxadiazol-3-yl]propionitrile(7) and 3-[4-amino-3-(1H-indol-3-yl-methyl) -5-thioxo-4,5-dihydro-[1,2,4]triazol-l -yljpropionitrile(8) were synthesized in good yields from the intermediate(1H-indol-3-yl)-acetic acid N’-(2-cyanoethyl)hydrazide(4).The chemical structures of the newly synthesized compounds were elucidated by their IR,~1H NMR and MS.Further,all the compounds were screened for their antimicrobial activity against Gram-positive,Gram-negative bacteria and also tested their ability toward anti-inflammatory activity.     

Synthesis of chiral fused heterocyclic compounds containing 1,2,4‐triazole ring

A series of new chiral (S)‐3‐ary1‐6‐pyrrolidin‐2‐yl‐[1,2,4]triazolo[3,4‐b]thiadiazole (II_1‐5), (S)‐1‐(3‐aryl‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐ethylamine (II_6‐8) and (S)‐1,2‐bis(3‐aryl‐[1,2,4]triazolo‐[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐ethylamine (II_9‐11) were prepared by the condensation of 3‐aryl‐4‐amino‐5‐mercapto‐1,2,4‐triazoles with different L‐amino acids in the presence of phosphorus oxychloride and evaluated for their antibacterial activity.