Synthesis of Heterobicyclic Nitrogen Compounds as Molluscicide Agents Derived from 6-Methyl-5-styryl-1,2,4-triazin-3-thiol: Part I

Some new heterocyclic nitrogen compounds 1-14 have been synthesized from cyclization of 5-styryl-3-mercapto-6-methyl-1,2,4-triazines 1 with active methylene and/or nitrogen compounds and were evaluated as molluscicidal agents. Significant molluscicidal activities for some of the products towards Biomophalaria Alexandrina snails were observed.     

Chloromethyl-, dichloromethyl-, and trichloromethyl-1,2,4-triazines and their 4-oxides: method for the synthesis and tele-substitution reactions with C-nucleophiles

A simple procedure was developed for the synthesis of 1,2,4-triazines and their 4-oxides containing the ClCH₂, Cl₂CH, or CCl₃ group at position 3 by cyclization of 2-aryl-2-hydrazono-1-oximinoethanes with the corresponding chloroacetonitriles. The reaction pathway depends on the number of halogen atoms in the acetonitrile used. The reactions with trichloroacetonitrile, monochloroacetonitrile, and dichloroacetonitrile afford 3-trichloromethyl-1,2,4-triazines, 3-chloromethyl-1,2,4-triazine 4-oxides, and a mixture of the corresponding dichloromethyltriazines and their 4-oxides, respectively. The reactions of 3-trichloromethyl-1,2,4-triazines with indoles and phenols are accompanied by tele-substitution with elimination of halogen from the trichloromethyl group to give 5-indolyl- (or 5-hydroxyphenyl)-3-dichloromethyl-1,2,4-triazines.     

Reactions of 1,2,4-triazines with nitromethide ion. A convenient method of preparation of 1,2,4-triazin-5-ylcarbaldehyde oximes and their synthetic applications

An efficient procedure for the preparation of 1,2,4-triazin-5-ylcarbaldehyde oximes 2a-f from 1,2,4-triazines 1a-f and nitromethide ion is described. The oximes 2c-d were converted into corresponding 5-cyano-1,2,4-triazines 6c-d . The latter compounds react easily with various nucleophiles to afford 5-substituted 1,2,4-triazines 7a-i and with 1-pyrrolidino-1-cyclohexene to form cyano derivative of 5,6,7,8-tetrahydroisoquinoline 9 .     

An unusual transformation of 5-acyl-1,2,4-triazines into 3-pyridyl-1,2,4-triazines via tandem Stille cross-coupling/aza Diels-Alder reaction

A new route to 3-heteroaryl-1,2,4-triazines possessing a keto substituent at C-5 of the 1,2,4-triazine core using a Stille cross-coupling procedure and their unexpected ring transformation into pyridyltriazines as a result of enolization of an acyl group catalyzed by metal ions, are reported.     

Synthesis of 3-amino-5H-pyrrolo[2,3-e]-1,2,4-triazines by Sonogashira/copper(I)-catalyzed heteroannulation

A Sonogashira/copper(I)-catalyzed heteroannulation sequence was developed to convert 3,5-diamino-6-chloro-1,2,4-triazines to the corresponding 3-amino-5H-pyrrolo[2,3-e]-1,2,4-triazine derivatives in good yields.     

Reaction of N-cyanoformimidates with some heterocyclic compounds. A new synthesis of 5-azaadenine and related compounds

3-Amino-1,2,4-triazoles and 2-aminobenzimidazole were reacted with N-cyanoimidates to give 5-amino-1,2,4-triazolo[2,3-a]-1,3,5-triazines (5-azaadenines) and 4-aminobenzimidazo[1,2-a]-1,3,5-triazines, respectively. The structures of the compounds obtained were confirmed through the comparison with some of the possible isomers prepared by independant methods.     

Nucleophilic substitution of hydrogen in the reaction of 1,2,4-triazin-4-oxides with cyanamide

It was shown that cyanamide can successfully be used in reactions of nucleophilic substitution of hydrogen with 1,2,4-triazin-4-oxides in the presence of a base to give 5-cyanoimino-1,2,4-triazines. It was found by¹³C NMR spectroscopy that these compounds and their alkylation products at the cyclic nitrogen atom exist in the form of 5-cyanoimino-2,5-dihydro-1,2,4-triazines. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1128–1130, June, 2000.     

3-氨基-5-取代苯氨基-6-苯基-1,2,4-三嗪的合成

3-氨基-1,2,4-三嗪化合物具有广泛的生理活性,如:治疗支气管扩张、抑制乳酸菌和症原虫繁殖杀菌等,因此,研究这类化合物合成方法应运而生。本文以苯甲酰基硫代甲酰胺为原料,进一步合成了氨基-5-取代苯氨基-6-苯基-1,2,4-三嗪。     

Synthesis of 2-amino-3,6-di(het)arylpyridines from 5-cyano-3,6-di(het)aryl-1,2,4-triazines and arylhydrazines via the SNipso/aza-Diels–Alder reaction sequence

Reaction between 5-cyano-3,6-di(het)aryl-1,2,4-triazines and arylhydrazines with the following aza-Diels–Alder autoclave reaction affords hardly available 2-amino-3,6-di(het)aryl-pyridines in up to 67% yield after two steps and in 75% yield for the one-pot way. The compounds obtained can be promising for medicinal chemistry.     

Aminovinyl ketones and aminovinyl esters as CCN building blocks for the synthesis of 1H-pyrrolo[3,2-e]1,2,4-triazines

5,6-Unsubstituted-3-aryl-1,2,4-triazines were found to react with aminovinyl ketones and aminovinyl esters in acetic anhydride to form derivatives of 3a,4,7,7a-tetrahydro-1H-pyrrolo[3,2-e]1,2,4-triazines in good yields.     

Azolo[5,1-<Emphasis Type="Italic">c</Emphasis>]-1,2,4-triazines as a new class of antiviral compounds

Synthetic methods, reactivity, and the properties of a new class of antiviral compounds, pyrazolo-, imidazo-, 1,2,4-triazolo[5,1-c]-1,2,4-triazinones, tetrazolo[5,1-b]-1,2,4-triazinones, and azoloannulated amino-1,2,4-triazines having structural similarity with biogenic purines and capable of mimicking them in metabolic processes are considered. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 967–995, May, 2008.     

Synthesis and Antimicrobial Activity of Some New Heterocyclic Schiff Bases Derived from 2-Amino-3-formylchromone

Some new hydrazone derivatives 3a–e have been obtained from 2-amino-3-formylchromone (1). Heterocyclization of thiocarbohydrazone derivative 3e via reaction with some electrophilic reagents afforded 1,2,4-triazoles 6–8 and 1,2,4-triazines 9–13. Condensation reactions of aldehyde 1 with o-aminoaldehydes and/or ketones afforded some new isolated and condensed heterocyclic systems 17, 19, and 20. The newly synthesized compounds were screened for their antimicrobial activity.     

An efficient route to 5-(hetero)aryl-2,4′- and 2,2′-bipyridines through readily available 3-pyridyl-1,2,4-triazines

A new route to substituted bipyridines based on a new method for the synthesis of substituted 3-pyridyl-1,2,4-triazines and their aza-Diels-Alder reactions is shown to be an efficient strategy for the preparation of structurally diverse bipyridine ligands.     

1,2,4-Triazine in Organic Synthesis. 16. Reactivity of 3-Substituted 6-Phenyl-1,2,4-triazines towards Phenylacetonitrile Anion in Polar Aprotic Solvents

The reactions of 3-X-6-phenyl-1,2,4-triazines (X = SMe, SPh, SO2Ph) with phenylacetonitrile anion in DMF were studied. In these reactions the ring transformation product 3-amino-4,6-diphenylpyridazine, the covalent addition product 3-X-5-(-cyanobenzyl)-6-phenyl-2,5-dihydro-1,2,4-triazine, and the ipso-substitution product 3-(1-cyano-1-phenylmethyl)-6-phenyl-1,2,4-triazine were obtained. Analogous reactions carried out in DMA gave only the addition products in excellent yields as diastereomeric mixtures of the corresponding 2,5-dihydro-1,2,4-triazines.     

3-Diethylamino-5-phenyl-1,2,4-diselenazolium-tetrachloroniccolat(II) — Synthese und Struktur

3-Diethylamino-5-phenyl-1,2,4-diselenazolium-tetrachloroniccolate(II) — Synthesis and Structure Bis-(N′, N′-diethyl-N-benzoylselenoureato)nickel(II) reacts with diphosgene in benzene to 3-diethylamino-5-phenyl-1,2,4-diselenazolium-tetrachloroniccolate(II). Its structure is confirmed by RKSA and ESCA. The compound consists of cations, which are planar fivemembered rings and of tetrahedral tetrachloroniccolate(II) anions. The complex is isomorphic with 3-diethylamino-5-phenyl-1,2,4-dithiazolium-tetrachloroniccolate(II).     

Tandem oxidation processes for the regioselective preparation of 5-substituted and 6-substituted 1,2,4-triazines

α-Hydroxyketones undergo MnO₂-mediated oxidation, followed by in situ trapping with 2-pyridylamidrazone, to give 3-pyridyl-5-substituted 1,2,4-triazines in a one-pot procedure, which avoids the need to isolate the reactive α-ketoaldehyde intermediates. By modifying this procedure to allow condensation prior to oxidation, the corresponding 6-substituted 1,2,4-triazines were obtained. The preparation of a novel unsymmetrical 2,2′-bipyridine using one of the pyridyl 1,2,4-triazines prepared herein is also described.     

Ethylenimine derivatives of some 1,2,4-triazines

The first 3-ethylenimino-1,2,4-triazines ( 9 ) have been synthesized from the corresponding 3-(β-chloroethyl)amino-1,2,4-triazines ( 8 ). In addition some 2,3-dihydroimidazo[1,2-b]-1,2,4-triazines and imidazo[1,2-b]-1,2,4-triazines were obtained. The stability, properties and potential therapeutic value of these compounds are discussed.     

Annelation of the thiazole ring to 1,2,4-triazines by tandem AN—AN or SN H—SN H reactions

The reactions of 3-aryl-1,2,4-triazines with aromatic thioamides and 4-arylthiosemicarbazides in acetic anhydride at room temperature afforded cyclic products of the tandem nucleophilic addition reactions, viz., tetrahydrothiazolo[4,5-e]-annelated 1,2,4-triazines, in good yields. The latter underwent aromatization in the presence of potassium permanganate.     

One-Step Synthesis of 5-Methyl-1,2,4-triazines by the Transformation of Their 5-Phenacyl Derivatives

Russian Journal of Organic Chemistry - A convenient one-step synthesis of 5-methyl-1,2,4-triazines by the transformation of 5-phenacyl-1,2,4-triazines under alkaline conditions was developed. The...     

Reaction of 4-Amino-3-methylthio-5-oxo-6-R-4,5-dihydro-1,2,4-triazines with Sulfonylacetic Acid Nitriles

The reactions of 4-amino-3-methylthio-5-oxo-6-R-4,5-dihydro-1,2,4-triazines with arylsulfonylacetonitriles and with dinitriles of sulfonyldiacetic acid and methylenebis(sulfonylacetic) acid have been studied. 7-Amino-3-R-8-(R'-sulfonyl)-1,4-dihydropyrazolo[5,1-c][1,2,4]triazin-4-ones have been synthesized and these are the first representatives of geminal sulfones in which the heterocyclic ring is bound directly to the sulfur atoms of the sulfonyl groups.