Investigation of nitrogen- and sulfur-containing heterocycles

The reaction of o-aminomercapto derivatives of pyrimidine, pyrazine, and pyridine, with -halo acid nitriles was investigated. The corresponding cyanoalkylthio heterocycles, which were converted to 6-amino derivatives of pyrimido[4,5-b]-, pyrazino[2,3-b]-, and pyrido-[2,3-b]-1,4-thiazines, were obtained. The structures of the substances obtained were confirmed by IR, UV, and PMR spectroscopy.See [10] for communication XXII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 944–948, July, 1972.     

Intensification of the Nitrate Anion Reduction on a Membrane Palladium Electrode

Polarization curves of electroreduction of nitrate anions in sulfuric acid aqueous solutions on a Pd/Pd palladium electrode with the opposite side kept at different constant potentials in the region of Pd–H -phase formation are compared. The reduction rate of nitrate anions is shown to be substantially higher on a membrane electrode, provided the conditions of hydrogen supply from the membrane's opposite side to the reaction zone are realized. This phenomenon is caused by the reduction of a chemisorbed intermediate (a certain N(III) form) by hydrogen diffused through the membrane. It is shown that the measurements of hydrogen diffusion currents through a membrane can be used in plotting hydrogen sorption isotherms in the Pd–H -phase.     

Investigation of nitrogen- and sulfur-containing heterocyclic compounds

The halogenation of 2,3-dimethylpyrazino[2,3-b][1,4]thiazin-6-one with bromine or 1 mole of sulfuryl chloride gives 7-bromo-and 7-chloropyrazino[2,3-b][1,4]thiazin-6-ones, while 2 moles of sulfuryl chloride give 7,7-dichloropyrazino[2,3-b][1,4]thiazin-6-one. A number of 7-amino-and 7,7-diaminopyrazino[2,3-b][1,4]thiazin-6-ones were obtained by the reaction of the appropriate halo derivatives with amines. Some of the pyrazino[2,3-b][1,4]thiazin-6-one derivatives inhibit the growth of interweavable tumors in animals.See [3] for communication XX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1498–1501, November, 1971.     

Investigation of nitrogen- and sulfur-containing heterocycles. 38. Reactions of 2-mercapto-3-ureidopyridines with halo β-diketones

The reaction of 2-mercapto-3-ureido-6-chloropyridine with chlorodibenzoylmethane in the presence of alkali leads to 2-(benzoylmethylthio)-3-benzamido-6-chloropyridine, whereas the reaction in the absence of alkali leads to 2-chloro-6-phenyl-7-benzoylpyrido[2,3-b] [1,4]thiazine. Under similar conditions 2-(diacetylmethylthio)-3-ureido-6-chloropyridine, 2-(acetylmethylthio)-3-ureido-6-chloropyridine, and 2-chloro-6-methyl-7-acetylpyrido[2,3-b][1,4]thiazine were obtained from 2-mercapto-3-ureido-6-chloropyridine and chloroacetylacetone. Treatment of 2-(diacetylmethylthio)-3-ureido-6-chloropyridine with alcoholic alkali leads to 2-(acetylmethylthio)-3-ureido-6-chloropyridine. 2-Chloro-6-phenyl-7-acetylpyrido-[2,3-b] [1,4]thiazine and 2-(benzoylmethylthio)-3-ureido-6-chloropyridine are formed in the reaction of 2-mercapto-3-ureido-6-chloropyridine with chlorobenzoylacetone in the presence of an equimolar amount of alkali, while 2-(benzoylmethylthio)-3-acetamido-6-chloropyridine is formed when excess alkali is used. See [1] for communication 37. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 787–790, June, 1980.     

Studies of 1-azabicyclics. 23. Nitration of 1,2-dihydropyrrolizine and its homologs

Nitration of 1,2-dihydropyrrolizine and its homologs with a mixture of nitric acid and acetic anhydride has been shown to give a mixture of 5-, 6-, and 7-nitro-1,2-dihydropyrrolizines. The distribution of isomers with respect to the position of alkyl substituents in the nonaromatic portion of the bicyclic is discussed.For Communication 22, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 320–324, March, 1986.     

Study of Nitrogen- and Sulfur-Containing Heterocycles. 57. Synthesis and Conversion of 4′-Substituted 5-(5-Amino-6-Pyrimidylthio)-2,2-Dimethyl-4,6-Dioxo-1,3-Dioxanes

By reaction of 4-substituted 5-amino-6-mercaptopyrimidines with 5-bromo-2,2-dimethyl-4,6-dioxo-1,3-dioxane, we have obtained 4′-substituted 5-(5-amino-6-pyrimidylthio)-2,2-dimethyl-4,6-dioxo-1,3-dioxanes. We have studied diazotization of these compounds by isoamyl nitrite. In the case of 4′-methoxy- and 4′-dimethylamino-substituted derivatives, we have obtained derivatives of novel heterocyclic systems: pyrimido[5,4-e][1,3,4]thiadiazine and pyrimido[5,4-e][1,3,4]thiadiazine-7-spiro-5′-1,3-dioxane, and in the case of the 4′-isopropylamino-substituted derivative we obtained 4-isopropyl-7-(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)-1,2,3-triazolo[5,4-d]pyrimidin-7-ylidene.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 613–623, April, 2005.     

6,7,8,9-Tetrahydrodipyrimido[4,5-b][4′,5′-e][1,4]thiazine derivatives. Synthesis and structure

The reaction of 5-amino-6-mercaptopyrimidines with 1,3-dimethyl-5-nitro-6-chlorouiracil in the presence of bases results in derivatives of 6,7,8,9-tetrahydrodipyrimido[4,5-b][4,5-e][1,4]-thiazine. If the 5-amino-6-mercaptopyrimdine contains a free or alkyl-substituted amino group at the 4-position, the tetrahydrodipyramidothiazines formed exist in a free radical form. The structure of the compounds formed has been established by spectral methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 258–264, February, 1989.     

Investigation of nitrogen- and sulfur-containing heterocycles

The corresponding N-(3-pyridyl)hydroxamic acid derivatives were obtained by reductive desulfuration of [2-(ethoxycarbonylmethylthio)-6-chloro-3-pyridyl]hydroxamic acid amide, benzylamide, and morpholide. The amides were synthesized by reaction of [2-(ethoxycarbonylmethylthio)-6-chloro-3-pyridyl]hydroxamic acid ester with diethylaminoethylamine and pyrrolidine. Heating of the ester and morpholide of [2-(ethoxycarbonylmethylthio)-6-chloro-3-pyridyl]hydroxamic acid with H₂SO₄ gives 2-chloropyrido[2,3-b] [1,4]thiazin-6-one.See [1] for communication XXVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 676–678, May, 1973.     

Investigation of nitrogen- and sulfur-containing heterocycles

2-Mercapto-3-ureido-6-chloropyridine reacts with the ortho, meta, and para derivatives of phenacyl halides to give 2-phenacylthio-3-ureido-6-chloropyridines, which are readily cyclized to 6-arylpyrido[2,3-b][1,4]thiazines regardless of the presence or absence of a substituent in the meta and para positions of the benzene ring.See [1] for communication XXIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 798–800, June, 1974.     

Investigation of nitrogen- and sulfurcontaining heterocycles

It is shown that 5-acetamido-6-carbethoxymethylmercaptopyrimidines (IV-VII) a r e formed by reaction of 5-amino-6-mercaptopyrimidines (I-IlI) with -chloro- and -chloro--methylacetoacetic esters in the presence of excess alkali, while 6-methyl-7-carbethoxy-pyrimidothiazines (XI-XIII) are formed in the absence of alkali; under similar conditions, hydroxyamino compounds VIII-X and 6-carbethoxymethylpyrimidothiazines XIV-XVI are obtained from I-III and -chloroacetoacetic ester. 6-Carbethoxy- and 7-carbethoxypyrimidothiazines XVII-XXI were synthesized from I-III and ethyl bromopyruvate, II, and chloroformylacetic ester, respectively.For Communication XV, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1423–1427, October, 1970.