The dehydrogenation of the alleged hexahydro-1,2,4-triazine-3,6-dione

The dehydrogenation of the alleged hexahydro-1,2,4-triazine-3,6-dione, recently reassigned the 3-amino-2,4-imidazolidinedione structure, gives upon reaction with bromine water or sodium hypobromite bis[3-(2,4-dioxoimidazolidinyl)]diazene instead of tetrahydro-1,2,4-triazine-3,6-dione as reported previously in the literature.     

UV photoelectron spectra of 5- and 6-azauracil

The He(I) photoelectron spectra of 5-azauracil (1,3,5-triazine-2,4(1H,3H)-dione) and 6-azauracil (1,2,4-triazine-3, 5(2H,4H)-dione) are presented. The spectra are assigned by using INDO/S calculations and comparison arguments with uracil. The first ionization energy in the title compounds is higher than in the usual nucleic acid bases.     

Diethylamine and triethylamine as sources of the dienophile component in the reverse azadiene synthesis with dimethylpyrimido[4,5-e]- and-[5,4-e]-1,2,4-triazinediones and 1,2,4,5-tetrazines

Diethylamine (DEA) and triethylamine (TEA) can function as sources for the two-carbon component in the reverse azadiene synthesis. Reaction of 5,7-dimethylpyrimido[4,5-e]-1,2,4-triazine-6,8-dione, 6,8-dimethylpyrimido-[5,4-e]-1,2,4-triazine-5,7-dione, or 1,2,4,5-tetrazine with an excess of DEA or TEA gives, respectively, the pyrido[2,3-d]pyrimidine-2,4-dione,pyrido[3,2-d]pyrimidine-2,4-dione, or pyridazine. The presence of an oxidant (atmospheric oxygen, MnO₂, or an electron-acceptor solvent) is required for the reaction to occur. Reaction of 5,7-dimethylpyrimido[4,5-e]-1,2,4-triazinedione with piperidine, morpholine, or under certain conditions DEA, results in opening of the triazine ring to give uracils with an amidine group in the 6-position.For preliminary communication, see [1, 2].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1545–1558, November, 1990.     

The synthesis of two novel pyridazines; A new ring system

The Diels-Alder reaction of 4,5-dimethylene-2,2-diphenyldioxolane with diethyl azodicar-boxylate and 4-phenyl-1,2,4-triazoline-3,5-dione was investigated. Reduction of the resultant adducts followed by hydrolysis provided hexahydro-4,5-dihydroxy-1,2-pyridazine dicarboxylic acid diethylester and 1,3,5,6,7,8-hexahydro-6,7-dihydroxy-2-pheny 1-2H-s-triazolo[1,2-α ]pyrida-zine-1,3-dione.     

A New Route to Substituted Pyrimido[5,4-e]-1,2,4-triazine-5,7(1H,6H)-diones and Facile Extension to 5,7(6H,8H) Isomers

A new route to substituted pyrimido[5,4-e]-1,2,4-triazine-5,7(1H,6H)-diones is outlined. The synthesis proceeds via pre-formed hydrazone intermediates, which are then condensed with an activated chlorouracil to build up the entire molecular framework, followed by a reductive ring closure to provide the parent series. The route has been extended to the isomeric pyrimido[5,4-e]-1,2,4-triazine-5,7(6H,8H)-dione class via the use of methylhydrazine as hydrazine surrogate, followed by regiospecific alkylation of the N(8)-H pyrimidotriazinediones with a range of alkyl and alkaryl substituents. This new methodology permits the generation of a wide range of compounds with variable substitution at the N(1), C(3), and N(8) positions for a heterocyclic scaffold with demonstrated pharmacological activity.     

α-Thioureidoalkylation of 4-alkyl- and 4-phenylthiosemicarbazides

Previously unknown 1,3-dialkyl-4,5-bis[4-alkyl(phenyl)thiosemicarbazido]imidazolidine-2-thiones and 4,5,7-trialkylperhydroimidazo[4,5-e]-1,2,4-triazine-3,6-dithiones have been synthesized by the α-thio-ureidoalkylation of 4-alkyl(phenyl)thiosemicarbazides using 1,3-dialkyl-4,5-dihydroxyimidazolidine-2-thiones.     

Biomimetic oxidation of metribuzin with hydrogen peroxide catalyzed by 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides

The biomimetic oxidation of metribuzin, a pre- and post-emergence herbicide with hydrogen peroxide catalyzed by 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides [TAPFe(III)Cl], has been studied yielding 6-t-butyl-3-methylthio-1,2,4-triazine-5(4H)-one, 4-amino-6-t-butyl-3,5(2H,4H)-dione and 6-t-butyl-1,2,4-triazin-3,5(2H,4H)-dione under various reaction conditions.     

Reactions of aroylpyruvic acids withS-methylisothiosemicarbazide hydroiodide and studies of the crystal structures of the reaction products

The reactions ofp-chlorobenzoyl- and benzoylpyruvic acids withS-methylisothiosemicarbazide hydroiodide gave 3-methylthio-6-(p-chlorophenacyl)-2,5-dihydro-1,2,4-triazin-5-one and 6-phenacyl-2,3,4,5-tetrahydro-1,2,4-triazine-3,5,-dione, respectively. The molecular and crystal structures of the compounds synthesized were studied by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 704–708, April, 1998.     

Intramolecular cyclization of hydrazides of (2-alkylthio-3,4-dihydro-6-methyl-4-oxo-3-pyrimidml)acetic acids to 1,2,3,4-tetrahydropyrimido[2,1-c]-1,2,4-triazine-3,6-diones

A method has been developed for the synthesis of 1,2,3,4-tetrahydropyrimido[2, 1-c]-1,2,4-triazine-3,6-diones by intramolecullar cyclization of hydrazides of (2-alkylthio-3,4-dihydro-6-methyl-4-oxo-3-pyrimidinyl)acetic acids in benzylamine.Vilnius University, Vilnius 2734. Translated Born Khimiya Geterotsiklicheskikh Soedinenii, No, 7, pp. 967–970, July, 1994. Original article submitted April 4, 1994.     

Über die Herstellung von substituierten 2,3,4,5-Tetrahydro-1,2,4-triazin-6-carbonitrilen und einige ihrer Abwandlungsreaktionen

Preparation of substituted 2,3,4,5-Tetrahydro-1,2,4-triazine-6-carbonitriles and some of its Derivatives. The synthesis of 4-substituted 2-aryl-2,3,4,5-tetrahydro-5-imino-3-oxo-1,2,4-triazine-6-carbonitriles ( 3 ), 2-aryl-2,3,4,5-tetrahydro-3, 5-dioxo-1,2,4-triazine-6-carbonitriles ( 4 ) and some 3-thioxo-derivatives thereof by a novel approach is described. In addition some possibilities for the derivatisation of these compounds are given.     

Electronic structure and mass spectra of substituted hexahydro-1,3,5-triazine-2-thiones

The electron density in the molecules of substituted hexahydro-1,3,5-triazine-2-thiones was calculated by the LCAO-MO SCF method in the MINDO/3 approximation. The mass spectra of substituted 5-methylhexahydro-1,3,5-triazine-2-thiones were studied, and a fragmentation scheme for the compounds is proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 976–980, July, 1986.     

Proton-acceptor properties of azahomofullerene and fullerenoaziridine containing a cyanuric acid fragment

¹³C and ¹H NMR and UV spectral studies on 1,3-diallyl-5-[4-(azahomo[60]fullereno)butyl]hexahydro-1,3,5-triazine-2,4,6-trione ([5,6]-open isomer) and 1,3-diallyl-5-[4-(aziridino[60]fullereno)butyl]hexahydro-1,3,5-triazine-2,4,6-trione ([6,6]-closed isomer), as well as quantum-chemical calculations, showed that only the latter possesses weakly basic properties.     

13C, 15N coupling constants in substituted 1,2,4-triazines-4-15N

The ¹³C,¹⁵N coupling constants in three 1,2,4-triazine-4-¹⁵N derivatives and in a substituted pyrimidine-1-¹⁵N have been determined and are compared with those in pyridine and quinoline. Of special interest are the data of the 5-(2-dimethylamino-1-propenyl)-3,6-dimethyl-1,2,4-triazine-4-¹⁵N, since one observes a characteristic alternation of the absolute value of J(¹³C,¹⁵N) along the sidechain and a hitherto unobserved very large ¹³C,¹⁵N coupling constant through four bonds of 3·9 Hz, the origin of which is attributed to the influence of the lone pair orbital on the ¹⁵N at position 4.     

The mass spectra of 1,2,4-triazine and some of its derivatives

The mass spectra of some esters of 1,2,4-triazine-3-carboxylic acid and of 1,2,4-triazine itself are reported, and their fragmentation patterns are analyzed. The syntheses of the methyl and of the t-butyl esters of 1,2,4-triazine-3-carboxylate are described.     

Formation of hexahydro-1,3,5-triazin-2-one and hexahydro-1,3,5-triazine2-thione derivatives in reactions of glycylglycine with paraformaldehyde andN,N′-disubstituted ureas and thioureas

Hexahydr-1,3,5-triazin-2-one and hexahydro-1,3,5-triazine-2-thione derivatives were shown to be formed selectively in reactions of glycylglycine with paraformaldehyde and N,N'-dialkylureas, NN'-diethylthiourea, and glycoluril.     

Comparative studies for selective deprotection of the N-arylideneamino moiety from heterocyclic amides: kinetic and theoretical studies. Part 2

4-Benzylideneamino-1,2,4-triazine-3,5(2H,4H)-diones (2-5), 6-styryl-1,2,4-triazine-3,5(2H,4H)-dione (6), and 6-styryl-2,3-dihydro-3-thioxo-1,2,4-triazin-5(4H)-one (7) were synthesized and pyrolyzed in the gas phase. The kinetic effect of changing the substituent on the triazine ring from hydrogen to methyl, phenyl, and styryl was measured. Analyses of the pyrolyzates of 2-5 showed the elimination products to be benzonitrile and the triazine fragment, while the pyrolyzates of 6 and 7 reveal the formation of cis- and trans-cinnamonitriles. Theoretical study of the pyrolysis reactions of 2-5 using an ab initio SCF method was investigated.     

Structural reassignment of the alleged 6-hydroxy-1,2,4-triazine-3,5-(2H,4H)dione

The reaction of 6-amino-1,2,4-triazine-3,5-(2H,4H)clione with sodium hydroxide or nitrous acid has been shown to give 5-hydroxy-1,2,4-triazole-3-carboxylic acid instead of 6-hydroxy-1,2,4-triazine-3,5-(2H,4H)dione as reported in the literature. The triazolecarboxylic acid was also obtained from the aminotriazine and hydrochloric acid.     

Synthesis of 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones and their conversion into 2-aryl-1,2,4-triazine-3,5-(2H,4H)odiones. A new synthesis of 1-aryl-6-azauracils

Treatment of 6-amino-5-arylazo-1,3-dimethyluracils with urea or N,N′-carbonyldiimidazole gave the respective 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones, which were hydrolyzed with alkali to afford 2-aryl-2,3,4,5-tetrahydro-3,5-dioxo-1,2,4-triazine-6-carboxylic acids (1-aryl-6-azauracil-5-carboxylic acids). Thermal decomposition of these carboxylic acids gave the corresponding 2-aryl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-6-azauracils). Methylation of the latter with methyl iodide gave the corresponding 2-aryl-4-methyl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-3-methyl-6-azauracils).     

1,2,4-Triazines, 9. The synthesis of novel 4-amino-1,6-dihydro-1,2,4-triazinones

3-Alkylthio-4-amino-1,6-dihydro-1,2,4-triazin-5(4H)-ones were synthesized by the reduction of 3-thio-4-amino-1,2,4-triazine-3,5(2.H,4H)-diones and successive S-alkylation. The regiospecific alkylation on the N-1 position or the exo amino group leads to a variety of 1,6-dihydro-1,2,4-triazin-5(4H)-one derivatives. An alternative synthesis of 3-thio-4-amino-1,6-dihydro-1,2,4-triazine-3,5(2H,4H)-diones was accomplished through the cyclization of 1-thiocarbohydrazidoacetamide derivatives.     

Protolytic and potential antithyroid properties of thioglycolurils and fused azolo-1,2,4-triazines

The protolytic properties and reactions with molecular iodine and blood serum proteins of 5,7-dimethyltetrahydro-1H-imidazo[4,5-e]-1,2,4-triazine-3,6(2H,4H)-dithione and (R)-1,3-dialkyl-4-[(2-hydroxybenzylidene)amino]-5-thioxohexahydroimidazo[4,5-d]imidazol-2(1H)-ones were studied. These compounds exhibit different chemical reactivities towards molecular iodine. The binding constants between these compounds and serum albumin attest to a considerable protein affinity of the compounds. The properties of the thiones make them promising as antithyroid agents.