A. Yu. Potapov

Three-component condensation of hetarylguanidines with aldehydes (ketones) and dicarbonyl compounds

The three-component condensation of benzoxa(thia)zolylguanidines, aldehydes (ketones), and β-dicarbonyl compounds (acetyl-and benzoylacetone, ethyl acetoacetate, acetoacetanilides, cyclohexanedione-1,3 and its derivatives) has been studied.

Regioselective and regiospecific reactions of ethyl ortho-(dimethylaminovinylazoloazinylcarboxylates with hydrazine

Selectivity of reactions of ethyl 4-[(E)-2(dimethylamino)vinyl]pyrazolo[5,1-c]-[1,2,4]triazino-3-ylcarboxylates and ethyl 7-[(E)-2-(dimethylamino)vinyl][1,2,4]triazolo[1,5]pyrimidine-6-ylcarboxylates with hydrazine in various solvents was studied. The formation of a pyridone cycle proceeds regiospecifically in dimethyl formamide or dimethyl acetamide. A regioselective cyclization resulting in fused 1,2-diazepines occurs in acetic or propionic acid.

Cascade Two- and Three-Component Cyclization Reactions Using 1,2-Diamino-4-Phenylimidazole and Cyclohexane-1,3-Diones

The reaction of 1,2-diamino-4-phenylimidazole with 5,5-R,R1-cyclohexane-1,3-diones and with the dimethyl formamide dimethyl acetal or triethyl orthoformate gives 7,7-R,R1-3-amino-1-phenyl-7,8-di-hydroimidazo[1,5-b]cinnolin-9(6H)-ones in good yield. These products may also be obtained from 1,2-diamino-4-phenylimidazole and 5,5-R,R1-(phenylaminomethylidene)cyclohexane-1,3-diones.

Three-component synthesis of 4-aryl-5-cyano-2-hetarylaminopyrimidines

Three-component condensation of benzooxazol-2-yl-, benzothiazol-2-yl-, and 5-ethoxycarbonyl-4-methyl-1,3-thiazol-2-ylguanidines with orthoesters and aroylacetonitriles afforded 4-aryl-5-cyano-2-hetarylaminopyrimidines.

2-Aminobenzimidazole in three-component cyclization reactions with formaldehyde and primary amines

Three-component condensation of 2-aminobenzimidazole and its N-substituted derivatives with formaldehyde and primary amines gave 1,2,3,4-tetrahydro[1,3,5]triazino[1,2-a]benzimidazoles.

Formation of passivating layers by 1,2,4-triazole derivatives on copper in aqueous solutions

Ellipsometry and electrochemical measurements are used to study the adsorption of some substituted 1,2,4-triazoles on copper and their effect on dissolution of copper in aqueous buffer solutions at pH 7.4. It is found that the adsorption of triazole compounds on copper is polymolecular at potential Е = 0.0 V, in relation to a normal hydrogen electrode. The first layer is described by the Temkin equation with free adsorption energy (−ΔGa0) = 55.2–76.3 kJ/mol and an energy heterogeneity factor that varies from 0.91 to 2.5. The maximum value of −ΔGa0 is found for an acid and a hydrogen sulfide corrosion inhibitor that is a mixture of triazole derivatives. The same inhibitor is the one least sensitive to the energy heterogeneity of the surface of a copper electrode, due to its high chemical reactivity and ability to be adsorbed on different active sites. This inhibitor is likely chemisorbed on copper and forms an ultrathin coating in an aqueous solution that is vastly superior to similar coatings produced by the familiar corrosion inhibitors of triazole group compounds in protecting against atmospheric corrosion.

Recyclization of maleimides with N-carboximide amides

A versatile synthetic approach towards 4-oxo-4,5-dihydro-1H-imidazol-5-ylacetanilides was elaborated. The target compounds result from recyclization of substituted N-aryl maleimides with carboximide amides in aprotic solvents.

Synthesis of polyazaheterocycles containing linearly bound 1,2,4-thiadiazole using enaminones

A reaction of N-substituted 5-amino-3-(2-oxopropyl)-1,2,4-thiadiazoles with dimethylformamide dimethyl acetal gave 3-(5-amino-1,2,4-thiadiazol-3-yl)-4-(dimethylamino)but-3en-2-ones, whose cyclization with hydrazine, guanidine, 1H-pyrazol-5-amines and 6-aminopyrimidin-4(3H)-ones led to 3-methyl-1H-pyrazole, 4-methylpyrimidin-2-amine, 5-methyl3-arylpyrazolo[1,5-a]pyrimidines, and 5-methyl-2-R-pyrido[2,3-d]pyrimidin-4(3H)-ones containing a 5-amino-1,2,4-thiadiazole fragment linearly bound at position 3.

Synthesis of new hydroquinolinecarbaldehydes

A number of new N-alkyl-6(8)-formylhydroquinolines have been synthesized. The Vilsmeier—Haack reaction of 7(8)-substituted N-alkyl-1,2-dihydroand N-alkyl-1,2,3,4-tetrahydroquinolines led to 6-formylhydroquinolines, whereas N-methyl-8-formylhydroquinolines were formed in the case of 6-substituted N-methyl-1,2-dihydroand N-methyl-1,2,3,4-tetrahydroquinolines.

New Method for Synthesis of the Hetero-Cyclic System – 1,2,3,4-Tetrahydro-Imidazo[5,1-f][1,2,4]Triazin-7-Amine

Imidazotriazines are used as dyes, luminophores, and corrosion inhibitors [1, 2]. Earlier these compounds were obtained on the basis of diaminopyridinium salts, and this was not economically feasible. We decided to study an alternative method for the preparation of imidazotriazines starting from 1,2-diaminoimidazoles. In the course of the investigations we found that 1,2,3,4-tetrahydroimidazo[5,1-f][1,2,4]triazin-7-amines 4a-e are formed during the reaction of 1,2-diaminoimidazoles 1a-c, obtained by the reaction between benzaldehyde guanylhydrazones and halo ketones [1], with formaldehyde and primary amines 2a,b.