Silver recovery with complexing sorbents based on 1-vinyl-1,2,4-triazole

The sorption activity of copolymers based on 1-vinyl-1,2,4-triazole toward silver ions was studied in relation to the copolymer structure and to the kind and concentration of acids. The copolymers were prepared by radical copolymerization of 1-vinyl-1,2,4-triazole with 1,1,3-trihydrotetrafluoropropyl methacrylate and divinylbenzene, with 1,1,3-trihydrotetrafluoropropyl methacrylate, methyl methacrylate, and N,N′-methylenebisacrylamide, with diethylene glycol divinyl ether, and with divinyl sulfide. The copolymers exhibit high sorption activity. They efficiently recover silver cations from acid solutions and behave as anion exchangers.     

Proton exchange in 1-vinyl-1,2,4-triazole and its derivatives

Proton exchange at C(₅) of the triazole ring has been studied in 1-vinyl-1,2,4-triazole, 1-ethyl-1,2,4-triazole, poly-1-vinyl-1,2,4-triazole, and their quaternary salts. The rate of exchange is catalyzed by bases and inhibited by acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1365–1368, October, 1987.     

Copolymerization of 1-Vinyl-1,2,4-triazole with 2-Hydroxyethyl Methacrylate

Radical copolymerization of 1-vinyl-1,2,4-triazole with 2-hydroxyethyl methacrylate in dimethylformamide and ethanol, initiated with azobis(isobutyronitrile), was studied. The copolymerization constants of this pair of monomers at low conversions and the microstructure parameters were determined. New highly hydrophilic thinly cross-linked copolymers were prepared from these monomers in the presence of crosslinking agents.     

1-Vinyl-4-alkyl-1,2,4-triazolium salts

Quaternary salts based on 1-vinyl-1,2,4-triazole have been synthesized. Alkyl i-odides and bromides and dimethyl sulfate served as the quaternizing agent. Polymeric quaternary salts of 1-vinyl-1,2,4-triazole have been obtained by alkylation of its polymer.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1412–1414, October, 1984.     

Intermolecular interactions of 1-vinyl-1,2,4-triazole in various solvents

The solvent effect on intermolecular interactions of 1-vinyl-1,2,4-triazole was estimated by ¹H NMR spectroscopy. It was shown that 1-vinyl-1,2,4-triazole molecules form homoassociates (molecular stacks) which are broken on dilution with CCl₄. In polar solvents (dimethylacetamide-d ₆, D₂O), monomer-solvent heteroassociates prevail.     

The reactivity of 1-vinyl-1,2,4-triazole in the radical copolymerization with crotonic aldehyde

Copolymerization of 1-vinyl-1,2,4-triazole with crotonic aldehyde under the conditions of free-radical initiation has been studied. 1-Vinyl-1,2,4-triazole was found to be more reactive than crotonic aldehyde. The composition and structure of copolymers were determined by the elemental analysis, IR and quantitative ¹³C NMR spectroscopy. New polyfunctional water-soluble copolymers possessing thermostability up to 300°C were obtained.     

Hydrophilic functional copolymers of 1-vinyl-1,2,4-triazole with vinylsulfonic acid sodium salt

The free-radical copolymerization of 1-vinyl-1,2,4-triazole with vinylsulfonic acid sodium salt was conducted. New thermally stable functional water-soluble copolymers of various composition were synthesized. The structure and properties of the obtained copolymers were confirmed by IR, ¹H NMR spectroscopy, and thermogravimetric methods. It was found that 1-vinyl-1,2,4-triazole has higher reactivity than sodium vinylsulfonate. TGA and DSC show that the produced copolymers are stable when heated to 260 °C.     

13C NMR Study of the Structure of Vinyl Chloride-1-Vinyl-1,2,4-triazole Copolymer

The structure of the copolymer prepared by radical copolymerization of vinyl chloride with 1-vinyl-1,2,4-triazole was studied by quantitative ¹³C NMR spectroscopy. The structural unit of the copolymer consists of the units of vinyltriazole and quaternized vinyltriazole, vinyl group, and four vinyl chloride units.     

Formation of composite polymeric coatings on pure iron

We have demonstrated possibility of electrochemical preparation of metal-polymer nanocomposites on pure iron and steel electrodes in the course of electrochemically initiated polymerization of 1-vinyl-1,2,4-triazole accompanied with cathode formation of metals. Silver nanoparticles have been uniformly distributed in the formed polymer matrix. The prepared composites possess excellent thermal stability.     

Plant coumarins: VI. Synthesis of 3-vinylfurocoumarin derivatives based on oreoselone

Palladium-catalyzed Heck reaction of oreoselone trifluoromethanesulfonate with various terminal alkenes (methyl acrylate, styrene, vinylpyridines, N-vinylpyrrole, and N-vinyl-1,2,4-triazole) led to the formation of the corresponding (E)-3-vinyl-7H-furo[3,2-g]chromen-7-ones. The yield was found to depend on the catalytic system and initial olefin structure.     

Intramolecular hydrogen bonds C-H?N in bisheterocyclic compounds according to 1H and 13C NMR data

Data of ¹H and ¹³C NMR spectra show that in 2,2??-bipyridyl, 1-vinyl-2(2??-pyridyl)benzimidazole, 1-vinyl-3-vinylsulfanyl-5-(2-furyl)-1,2,4-triazole, and 1-vinyl-5-vinylsulfanyl-3-(2-furyl)-5-vinylthio-1,2,4-triazole exists a weak intramolecular hydrogen bond between the heterocyclic fragments. It causes a downfield shift of the bridging proton signal in the ¹H NMR spectrum by 0.6?C0.7 ppm and an increase in the corresponding direct coupling constant ¹³C-¹H by 1.5?C2.0 Hz. These variations in the spectral parameters can be efficiently used in the conformational analysis for establishing with the use of NMR method which conformers are predominantly populated in the heterocyclic compounds.     

Study of the rotational isomerism of 1-vinyl-1,2,4-triazoles by 1H and 13C NMR spectroscopy

Quantitative evaluations of the percentages of rotational isomers in 1-vinyl-1,2,4-triazoles were obtained. The population of the s-cis(N₍₂₎) form in 1-vinyl-1,2,4-triazole is greater by a factor of two than in the s-trans form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 365–368, March, 1991.     

Electrochemical copolymerization of N-vinylazoles with acrylic acid at iron and copper electrodes

Possibility of electrochemical synthesis of polymeric coatings based on copolymers of 1-vinyl-1,2,4-triazole and 1-vinylimidazole with acrylic acid at iron and copper electrodes with aryldiazonium salt as initiator has been demonstrated. Dielectric properties of the so prepared polymeric coatings have been studied. Degradation of 1-vinylimidazole copolymers with acrylic acid has been slower than that of other acrylic acid copolymers.     

Synthesis and single-crystal X-ray diffraction studies of 1-β-D-ribofuranosyl-1,2,4-triazole-3-sulfonamide and certain related nucleosides

1-β-D-Ribofuranosyl- 21 , 1-(2-deoxy-β-D-erytftro-pento fur anosyl)- 27 and 1-β-D-arabinofuranosyl- 29 derivatives of 1,2,4-triazole-3-sulfonamide ( 19 ) have been prepared. Glycosylation of the silylated 19 with 1,2,3,5-tetra-0-acetyl-β-D-ribofuranose ( 5 ) in the presence of trimethylsilyl triflate gave the corresponding blocked nucleoside ( 20 ), which on ammonolysis afforded 1-β-D-ribofuranosyl-1,2,4-triazole-3-sulfonamide ( 21 ). Stereospecific glycosylation of the sodium salt of 19 with either 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-α-D-erythro-pentofuranose ( 22 ) or 1-chloro-2,3,5-tri-0-benzyl-α-D-arabinofuranose ( 23 ) provided the corresponding protected nucleosides 26 and 28. Deprotection of 26 and 28 furnished 1-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,4-triazole-3-sulfonamide ( 27 ) and 1-β-D-arabinofuranosyl-1,2,4-triazole-3-sulfonamide ( 29 ), respectively. 2-0-D-Ribofuranosyl-1,2,4-triazole-3(4H)-thione ( 7 ) and 4-β-D-ribofuranosyl-1,2,4-triazole-3(2H)-thione ( 9 ) were also prepared utilizing either an acid catalyzed fusion of 1,2,4-triazole-3(1H,2H)-thione ( 4 ) with 5 , the reaction of 5 with silylated 4 in the presence of trimethylsilyl triflate, or by ring closure of 4-(2,3,5-tri-0-benzoyl-β-D-ribofuranosyl)thiosemicarbazide ( 10 ) with mixed anhydride and subsequent deacylation. The synthesis of 1-β-D-ribofuranosyl-3-benzylthio-1,2,4-triazole ( 15 ) has also been accomplished by the silylation procedure employing 3-benzylthio-1,2,4-triazole ( 13 ) and 5 to give 1-(2,3,5-tri-0-acetyl-β-D-ribofuranosyl)-3-benzylthio-1,2,4-triazole ( 14 ). Deacetylation of 14 furnished 15 . The structural assignments of 7, 14 and 21 were made by single-crystal X-ray diffraction analysis and their hydrogen bonding characteristics have been studied. The sulfonamido-1,2,4-triazole nucleosides are devoid of any significant antiviral or antitumor activity in cell culture.     

Polarographic reduction of 1-substituted 1,2,4-triazoles

The polarographic reduction of 1-substituted 1,2,4-triazoles in dimethylformamide (DMF) and acetonitrile was studied. 1-Methyl-, 1-ethyl-, and 1,2,4-triazoles are not reduced on a mercury electrode over the range of potentials accessible for polarography. 1-Phenyl-1,2,4-triazole and 1-vinyl-1,2,4-triazole are reduced in acetonitrile via a one-electron mechanism at high negative potentials. The reduction of 1-vinyl-1,2,4-triazole is accompanied by polymerization of the electrolysis products. A possible mechanism for the electrochemical reduction is discussed. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 408–410, March, 1980.     

Spectroscopic identification of some derivatives of 3,4-diamino-4H-1,2,4-triazole and 3-Hydrazino-4H-1,2,4-triazole

Spectroscopic methods (ir, ¹H- and ¹³C-nmr, ms and uv) have been used for the structural elucidation and identification of different isomeric 1,2,4-triazole derivatives, obtained by cyclisation reactions from appropriate diaminoguanidines. The four compounds 3,4-diamino-4H-1,2,4-triazole, 3-hydrazino-4H-1,2,4-triazole, 3-amino-4-(2,6-dichlorobenzylideneamino)-4H-1,2,4-triazole and 3-(2,6-dichlorobenzylidenehydrazino)-4H-1,2,4-triazole, were chosen as representative structures to illustrate the general spectroscopic properties for 3,4-diamino- and 3-hydrazino-substituted 4H-1,2,4-triazoles and the corresponding hydrazones, with different substituents in the 5-position of the triazole ring (alkyl-, aralkyl-, mercapto-, hydroxy- and amino-groups). Nmr and uv spectroscopy were found to be the best methods for confirmation of the different series of hydrazones, while ir and nmr were found to be suitable for the structural elucidation of compounds in the series of 3,4-diamino- and 3-hydrazino-4H-1,2,4-triazoles, respectively.     

Flocculation of Kaolin Suspensions with Poly-1-vinyl-1,2,4-triazole,Its Quarternary Ammonium Salt,and Their Mixtures with Anionic Polyelectrolytes

Homo- and copolymers of 1-vinyl-1,2,4-triazole with acrylamide and quarternary salt of polyvinyltriazole were prepared. The flocculation power of these (co)polymers was studied using model kaolin suspensions.     

Syntheses of substituted-1,2,4-triazoles

Starting from the readily available 3-phenylpropionitrile, 3-(or 5-)(2-phenethyl)-1,2,4-triazole 3 was prepared. Reaction of compounds 3 with diazomethane afforded 1-methyl-3-(2-phenethyl)-1,2,4-triazole (4) and 1-methyl-5-(2-phenethyl)-1,2,4-triazole (5) . Reaction of compound 3 with methanesulfonyl chloride, benzenesulfonyl chloride or p-toluenesulfonyl chloride afforded only one of the expected isomer; namely compounds 6 , 7 and 8 respectively.     

Microwave-assisted three component synthesis of novel bis-fused quinazolin-8(4H)-ones linked to aliphatic or aromatic spacer via amide linkages

Abstract

A novel series of bis(tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8-ones) and bis(tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolinones) containing amide linkages were regionselectively prepared via a three-component reaction of bis(aldehydes) with dimedone and 3-amino-1,2,4-triazole (or 2-aminobenzimidazole) under conventional heating as well as under microwave irradiation.     

Synthesis and study of thermal stability of 3-nitro-1,2,4-triazole N-nitroxy-and N-azidomethyl derivatives

A method for the preparation of new 3-nitro-1,2,4-triazole derivatives has been suggested based on modification of the N-hydroxymethyl group by nitration and nucleophilic substitution reactions. Thermal stability of 3-nitro-1,2,4-triazole N-nitroxy- and N-azidomethyl derivatives, as well as of dinitrates, 5,5′-dinitro-2,2 ′-bisnitroxymethyl-2 H,2′H-3,3 ′-bi(1,2,4-triazole) and -(nitromethylene)bis(1,2,4-triazole), has been studied.