Synthesis of 8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine

8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine has been synthesized by the interaction of 6-tert-butyl-3-hydrazino-1,2,4-triazolo[3,4-c]-1,2,4-triazin-5-one with formic acid. The conditions of carrying out the reaction are discussed. Spectral characteristics are given.     

Study of the Products of Iodocyclization of 4-Allyl-5-phenyl-1,2,4-triazole-3-thione

The interaction of 4-allyl-5-phenyl-1,2,4-triazole-3-thione with iodine proceeds with the formation of a mixture of 6-iodomethyl-3-phenyl-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole and 6-iodo-3-phenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b]-1,3-thiazine. The structures of the cyclization products obtained were established on the basis of the ¹H NMR spectra of their dehydroiodinated derivatives. 6-Methyl-3-phenylthiazolo[2,3-c]-1,2,4-triazole, 3-phenyl-5H-1,2,4-triazolo[3,4-b]-1,3-thiazine, and 3-phenyl-7H-1,2,4-triazolo[3,4-b]-1,3-thiazine are formed on eliminating HI from the cyclization products.     

Acid cyclization of amino-substituted heterocycles. Synthesis of 1,3-dioxo- pyrrolo[3,4-<Emphasis Type="Italic">c</Emphasis>]- and thieno[3,4-<Emphasis Type="Italic">c</Emphasis>]isoquino- lines and cinnolines

The reaction of 3-amino-4-(3,4-dimethoxyphenyl)maleimide and the methyl esters of 3-amino-4-(3,4-dimethoxyphenyl)-5-R-thiophene-2-carboxylic acids with carbonyl compounds and nitrous acid has been investigated. Dioxopyrrolo[3,4-c]- and thieno[3,4-c]isoquinolines and cinnolines were obtained. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 449-454, March, 2009.     

Interaction of 7-Chloro-9-methylthio-3-phenylpyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine with Some Nucleophiles

The reactions of 7-chloro-9-methylthio-3-phenylpyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine (1) with some nucleophiles have been studied. Substitution of the chlorine atom with hydrogen occurs with ammonia in DMSO to give 9-methylthio-3-phenylpyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepin-7(8H)-one. With a methanolic solution of ammonia the 7-methoxy derivative is formed. Reaction of compound 1 with an excess of sodium methoxide in methanol gave 6,7-dimethoxy-9-methylthio-3-phenyl-5,6-dihydropyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine. The corresponding 7-substituted derivatives were obtained when compound 1 was heated with morpholine or 2-(dimethylamino)ethylamine. The azomethine bond of the thiadiazepine ring is reduced by sodium borohydride to give the corresponding 5,6-dihydro derivatives.     

Synthesis and structure of diastereomeric trans-3,4-diamino-2,2,6,6-tetramethylpiperidine1-oxyl derivatives

The reaction of 3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl with (1S)-(+)-camphor-10-sulfonyl chloride gives a mixture of diastereomeric 4-monosulfonylamino derivatives. The products of their acylation have been obtained. The 3,4-bis-[(1S)-camphor-10-sulfonylamino] derivative was synthesized and resolved to individual diastereomers. For one of them thetrans relationship of the 3- and 4-substituents and the absolute (3S,4R)-configuration were established by X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 367–372, February, 1993.     

Phenolic compounds from the aqueous extract of Acacia catechu

From the aqueous extract of Acacia catechu,two new phenolic compounds(3R,4R)-3-(3,4-dihydroxyphenyl)-4-hydroxycy-clohexanone (1) and(4R)-5-(1-(3,4-dihydrophenyl)-3-oxobutyl)-dihydrofuran-2(3H)-one(2) were obtained.Their structures were determined on the basis of spectroscopic analysis.Free-radical scavenging activities of them were evaluated.     

Crystal Structures of 5-Nitro- and 5-Ethoxycarbonyl-Substituted 6-Phenyl-4-(3-fluorophenyl)-3,4-dihydro-(1H)-pyrimidin-2-ones

The crystal structures of 5-nitro- and 5-ethoxycarbonyl-substituted 6-phenyl-4-(3-fluorophenyl)-3,4-dihydro-(1H)-pyrimidin-2-ones were determined by X-ray diffraction analysis. Conformational peculiarities of the structures have been revealed and compared with data for other biologically active dihydropyrimidinones.     

2-Chloro-3-quinolinecarboxaldehyde in the Synthesis of Condensed Quinoline Systems. 1. Synthesis of Derivatives of 3,4-Dihydro-2H-[1,3]thiazino[6,5-b]quinolines

A method for the synthesis of derivatives of previously unknown heterocyclic systems - 3,4-dihydro-2H-[1,3]thiazino[6,5-b]quinolines - has been developed based on 7,8-dimethyl-2-chloro-3-quinolinecarboxaldehyde via the consecutive steps of conversion into its Schiff's base with a primary amine, reduction to the corresponding aminomethyl derivative, conversion to the thiourea with isothiocyanates, and heterocyclization by intramolecular substitution of the chlorine atom.     

Formylation of 3,4-Dihydropyrrolo[1,2-a]pyrazines

Formylation of 3,4-dihydropyrrolo[1,2-a]pyrazines containing alkyl or aryl substituents at position 1 has been studied under the conditions of the Vilsmeier reaction. The direction of the reaction depends on the structure of 3,4-dihydropyrrolo[1,2-a]pyrazine starting materials. Formylation of 1-methyl-substituted 3,4-dihydropyrrolo[1,2-a]pyrazines occurs at the methyl group.     

The Use of 4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one as “Masked” α-Bromo-α'-Hydroxy Ketone in the Synthesis of Heterocyclic Systems

4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one was obtained on the basis of the readily obtainable 4-methylene-5,5-dimethyl-1,3-dioxolan-2-one. It forms 2-imidazo[1,2-a]pyridin-2-yl-2-propanol with 2-aminopyridine, 11a-hydroxy-1,1-dimethyl-3-oxo-1,5,11,11a-tetrahydro[1,3]oxazolo[3,4-a]pyrido[1,2-d]-10-pyrazinium bromide with 2-(aminomethyl)pyridine, and the corresponding derivative of 4-hydroxyoxazolidin-2-one with 2-(3,4-dimethoxyphenyl)ethylamine. The last product was converted by intramolecular amidoalkylation without isolation into 10b-(bromomethyl)-8,9-dimethoxy-1,1-dimethyl-1,5,6,10b-tetrahydro[1,3]oxazolo[3,4-a]isoquinolin-3-one.