Search

An approach was developed for the synthesis of polyfunctionalized pyrimidines based on analogs of 1,2,4-triketones. Acetal-substituted β-diketones are involved in the condensation with amidines in the presence of an excess of (EtO)3B/Et3N in acetonitrile. The conditions of the acid hydrolysis of acetal-containing pyrimidines were found to depend on the nature of substituents in diazine. The use of 1,2,4-triketone in the condensation with amidine allows the synthesis of acetylpyrimidine in one step. [ABSTRACT FROM AUTHOR]

The methods of synthesis of fluorine-containing O, N, S-heterocyclic compounds, such as diazines, oxazines, thiazolines, oxazolines, quinoxalines, benzoxazines, benzothiazines, imidazolidines, and glycolurils, based on the reactions of perfluoro- and polyfluorooxiranes with bifunctional nucleophilic reagents, are presented in the review. Significant influence of the solvent nature on the composition and structure of the obtained compounds is demonstrated. [ABSTRACT FROM AUTHOR]

Earlier unknown meso-substituted azinylcalixarenes were obtained by a direct cross-coupling of 2-lithium-25,26,27,28-tetramethoxycalix[4]arenes with mono- and diazine N-oxides without transition metal catalysis. [ABSTRACT FROM AUTHOR]

The B3LYP/6-31G** quantum chemical method was used to study the mechanism of the oxidative alkylamination of diazinones taking 1,3,6-trimethylpyrimido[4,5- d]pyrimidine-2,4,7(1 H,3 H,6 H)-trione (lumazinone) as an example. The first limiting step of this reaction included a nucleophilic addition of alkylamine with the formation of the σ-adduct, which was oxidized by potassium permanganate in the second step. The alkylamination step proceeded in the associates formed by the lumazinone dimer and several alkylamine molecules involved in both the nucleophilic attack and the bifunctional catalysis of the process. The correlation of the Parr indices with the experimental data was studied for a number of diazinones. [ABSTRACT FROM AUTHOR]

Fluorinated 2-amino-5-phenyl-1,3,4-thiadiazines were obtained for the first time. A study of their tautomeric structures revealed that trifluoromethyl-containing 1,3,4-thiadiazines exist as the 4 H-tautomer in both solutions and the solid state, while their monofluoroaryl analogs exist as the 6 H-tautomer. [ABSTRACT FROM AUTHOR]