Cyclizations with hydrazones of nitroglyoxalic acid. Synthesis and structure of tetrazolo[5,1-b][1,2,4]triazines

Condensation of tetrazolylhydrazone of ethyl nitroglyoxalate with aromatic amines gives rise to derivatives of 5-arylamino-6-oxo-6,7-dihydrotetrazolo[5,1-b][1,2,4]triazine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1668–1672, December 1986.     

Reaction of acridine proton salts with arylamines in the presence of sulfur

The reaction of acridine proton salts with arylamines in the presence of sulfur was studied. It is shown that various arylamines of the benzene and naphthalene series, both free and substituted, form the corresponding aminoarylacridines in high yields in this reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 112–114, January, 1971.     

Supramolecular systems formed by calix[4]resorcinarenes and surfactants in chlorophorm

Capacity titration and ¹H NOESY 2D NMR were applied to investigation of intermolecular interactions and aggregation of amphiphilic calix[4]resorcinarenes (CRA 1, 2) modified with 1,2,4-triazine (1) and oxazine (2) functions in chloroform in the presence of cationic (3) and non-ionic (4) surfactants (SAA). Critical concentrations of micelle formation (CMC) indicate that the ability of CRA 1, 2 to form supramolecular aggregates like micelles or hybrid micelles with SAA 3, 4 only weakly depends on the constitution of CRA functional groups. In the case of the hybrid micelles, when CMC are defined by the nature of surfactants 3 or 4, the methyl and methylene groups of the hydrophobic fragments (CRA 1, 2) were found to interact with the hydroxy groups of SAA 3 and ethylene oxide moieties of SAA 4.     

Protolytic equilibrium of certain annelated azoloazines

The first and second protonations of annelated azoloazines have been investigated quantitatively in aqueous solution. Compounds investigated were pyrazolo[1,5-a]pyrimidine (pK_BH ^– 0.03±0.02, pK_BH ²⁺ –7.87±0.30), 1,2,4-triazolo[4,3-b]-1,2,4-triazine (pK_BH ⁺ –0.04±0.02, pK_BH ²⁺ –8.00±0.10), 1,2,4-triazolo[1,5-a]pyrimidine (pK_BH ⁺ 0.21±0.03, pK_BH ²⁺ –9.00±0.09) and its 6R derivatives (R=NO₂, Br, Cl). The annelated azoloazines studied are weaker bases than their unannelated analogs. According to quantum chemical calculations (AM1), protonation of these heterocycles may occur both at the azole and the azine fragments of the molecule.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 816–824, June, 2000.     

Cyclization of (1,2,4,5-tetrazin-3-yl)hydrazones to 3,7-dihydro-1,2,4-triazolo[4,3-b]-1,2,4,5-tetrazines

The intramolecular cyclization of (6-R-1,2,4,5-tetrazin-3-yl)hydrazones of ketones (R is 3,5-dimethylpyrazol-1-yl, 4-methylimidazol-1-yl, or 2-alkylidenehydrazino) giving rise to the previously unknown 3,7-dihydro-1,2,4-triazolo[4,3-b]-1,2,4,5-tetrazines, including spiro compounds, was studied. The reactivity and the yields of the reaction products depend on the structure of the alkylidene fragment and the nature of the substituent in the tetrazine ring.

     

Design of fused systems based on σH-adducts of 6-nitro-1,2,4-triazolo[1,5-a]pyrimidine with π-excessive heteroaromatic compounds

Russian Chemical Bulletin - A new method was developed for the construction of tetra- and pentacyclic fused systems based on σH-adducts of 6-nitro-1,2,4-triazolo[1,5-a]pyrimidine with...