Nitroazines. 19. Prototropic tautomerism in 6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[5,1-c][1,2,4]triazines

Prototropic reactions of 6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[5,1-c][1,2,4]triazines is tautomeric as established from photoionization results. The ratios of the tautomers in the gas phase and in solution have been determined by mass and ¹³C NMR spectroscopy.For Communication 18 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1555–1559, November, 1992.     

Synthesis of 7-Alkyl(aryl)-6-alkoxycarbonyl-5-fluoroalkyl-1,2,4-tri(tetr)azolo[1,5-a]pyrimidines

Fluorinated 3-oxo esters react with aldehydes and 3-amino-1,2,4-triazoles and 5-aminotetrazoles to give, respectively, 7-alkyl(aryl)-6-alkoxycarbonyl-5-fluoroalkyl-1,2,4-triazolo[1,5-a]pyrimidines and -tetra-zolo[1,5-a]pyrimidines. The same heterocyclic products can be obtained by reaction of 2-benzylidene-2-fluoroacyl esters with the corresponding aminoazoles.     

Synthesis and hydroxydeamination in the series of 6-aryl- and 6-benzoimidazolyl-7-aminoazolo[5,1-c]-1,2,4-triazines

The replacement of the amino group with the hydroxy group was examined in the series of 6-aryl- and 6-benzoimidazolyl-7-aminoazolo[5,1-c]-1,2,4-triazines. These reactions provide a convenient synthetic procedure for the preparation of fused azolo[5,1-c]-1,2,4-triazin-7-ones.     

A new approach to the synthesis of lamotrigine and other 3,5-diamino-1,2,4-triazine derivatives

A new in principle method for the synthesis of 6-aryl(hetaryl)-3,5-diamino-1,2,4-triazines by decomposition of pre-synthesized tetrazolo[1,5-b][1,2,4]triazines was developed. The advantages of this method over traditional methods were demonstrated using the synthesis of a modern antiepileptic preparation lamotrigine, as an example.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 713–719, March, 2005.     

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 antiviral activity of nucleoside analogs based on 1,2,4-triazolo[3,2-<Emphasis Type="Italic">c</Emphasis>][1,2,4]triazin-7-ones

Nucleoside analogs containing hydroxybutyl, hydroxyethoxymethyl, allyloxymethyl, and propargyloxymethyl fragments were synthesized based on 1,2,4-triazolo[3,2-c][1,2,4]triazin-7-ones isosteric to purine bases. Some of the compounds obtained inhibit in vitro reproduction of influenza and respiratory syncytial virus infection.     

Synthesis of derivatives of pyrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines and imidazo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines proceeding from alkyl 2-benzylidene-3-oxo-3-fluoroalkylpropionates

Methods were developed of the synthesis of alkyl 2-hydroxy-2-fluoroalkyl-4-phenyl-1,2,3,4—tetrahydroimidazo-[1,5-a]pyrimidine-3-carboxylates and alkyl-5-hydroxy-2,7-diphenyl-5-fluoroalkyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-6-carboxylates by regioselective [3+3]-cycloaddition of 5-aminoimidazole or 5-aminopyrazole to alkyl 2-benzylidene-3-oxo-3-fluoroalkylpropionates at the fluoroacylvinyl fragment.