Synthesis and some reactions of 3-cyanopyridine-2-thiones

New methods for the synthesis of 3-cyanopyridine-2-thiones by the reaction of -keto nitroles with sulfur and by condensation of chalcones or benzylideneacetone with cyanothioacetamide are given. The compounds obtained were used in various reactions for the preparation of alkylated products, disulfides, and condensed heterocycles, viz., thieno[2,3-b]pyridines and pyrido[2,3:2,3]thieno[4,5-d]-pyrimidines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 377–382, March, 1981.     

New approaches to the synthesis of functionally substituted pyrido[3′,2′:4,5]thieno[3,2-b]pyridines and the structure of the products obtained

Substituted pyrido,[3',2':4,5]thieno[3,2-b]pyndines were obtained by the reaction of 3-amino-2-benzoylthieno [2,3-b]pyridines with malononitrile and the reaction of 3-cyanopyridine-2(IH)-thiones with 2-aryl-3-bromo-I,I-dicyanopropene. 2-Amino-4-(4-bromophenyl)-7, 9-dimethyl-3-cyanopyrido [3',2':4,5]thieno[3, 2-b]-pyridine was used for the synthesis of a derivative of pyrido[3",2":4', 5']thieno[2',3':5,6]pyrido[2,3-d]-pyrimidine. The structure of these compounds was confirmed by spectral data and x-ray diffraction structural analysis.Deceased.     

Regio- and stereoselectivity of the reactions of pyridinium and picolinium salts and ylids with nitriles containing a nucleofugic group

The reaction of pyridinium, 2-picolinium, and 3-picolinium ylids with tetracyanoethylene, ethoxymethylenemalononitrile, and (dimethylthio)methyl-enecyanamide in the presence of organic bases proceeds regio- and stereo-selectively to give substituted pyridinium 1,4-ylids, 2-(2-propen-1-ylidene)-1,2-dihydropyridines, and 5-(1-pyridino)pyrimidin-4-olates, respectively. The reaction of 1-phenacylpyridinium bromide and tetracyanoethylene leads to 1-phenacylpyridinium tricyanoethenolate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 939–942 April, 1990.     

Cyclization reactions of nitrils. 29. Regioselective synthesis of 6-aryl-3-cyano-2(1H)-pyridinethiones and the corresponding selenones and their characteristics

The condensation of cyanothio- and cyanoselenoacetamide with 3-aryl-3-oxo-1-piperidino-1-propene or sodium 3-aryl-3-oxo-1-propen-1-olate takes place regioselectively with the formation of the 6-aryl-3-cyano-2(1H)-pyridinethiones or the corresponding selenones. Thieno[2,3-b]pyridines, thiazolo[3,2-a]pyridinium salts, and other annellated heterocycles were obtained from the 6-aryl-3-cyano-2(1H)-pyridinethiones.For Communication 28, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 805–812, June, 1988.     

The first stable examples of compounds containing both diazonium and acyl azide,and synthesis of a new pyrazino[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one heterocyclic system

The first stable compound containing both N₂⁺BF₄^? and CON₃ functional groups – 8-azidocarbonyl-3-(tert-butyl)-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-7-diazonium tetrafluoroborate was synthesized, and its stability and reactivity discussed. The Curtius rearrangement of 7-azido-3-(tert-butyl)-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carbonylazide was investigated, and the synthesis of a novel heterocyclic system –pyrazino[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one is described.     

Synthesis of heterocyclic compounds from 4-formylpyrazoles

Formylation of pyrazole and 2,5-dimethylpyrazole gave a number of pyrazole-containing aldehydes, which can be used to obtain chromenes, tetrahydrochromenes, 1,4-dihydropyrano[2,3-c]pyrazoles, pyrano[3,2-c]chromenes, thiochromeno[4,3-b]pyrans, pyrano[3,2-c]-quinolines, and thiazolo[3,2-a]pyridines.     

One-step synthesis of substituted 6-amino-5-cyanospiro-4-(piperidine-4')- 2H,4H-dihydropyrazolo[3,4-b]pyrans

Three-component condensation of 4-piperidinones (7), 5-pyrazolones (8), and malononitrile (4) proceeds chemically and electrochemically and is a convenient one-step means of synthesis of substituted 6-amino-5-cyanospiro-4-(piperidine-4')-2H,4H-dihydropyrazolo[3,4-b]pyrans (12). The electrochemical reactions proceed under milder conditions and with yields 12-15% greater than those of the reactions catalyzed by chemical bases.     

Synthesis of substituted thiazolo[4,5-b]pyridines and other annulated heterocycles via SN2→Thorpe-Ziegler→Thorpe-Guareschi domino reactions

A new combinatorial method for the preparation of substituted thiazolo[4,5-b]pyridines, which utilizes cyanoacetamide, heterocumulenes (isothiocyanates, carbon bisulfide), and ethyl-4-chloroacetoacetate in a new S_N2→Thorpe-Ziegler→Thorpe-Guareschi domino reactions has been developed. The obtained thiazolo[4,5-b]pyridines were then used together with aldehydes and malononitrile in another Knoevenagel reaction→Michael reaction→hetero-Thorpe-Ziegler domino reaction for the synthesis of substituted 4,6-dihydro-5H-pyrano[2,3-d]thiazolo[4,5-b]pyridines.     

Regio- and stereodirectivity in the reactions of isoquinolinium ylides with unsaturated nitriles

Reactions of isoquinolinium ylides with arylmethylenemalonitriles involve 1,3-dipolar cycloaddition, with the highly regio- and stereoselective formation of 2-aryl-3-benzoyl(or carbamoyl)1,1-dicyano-2,3-trans-1,2,3,10b-tetrahydropyrrolo[2, 1-a]isoquinolines. In contrast, N-phenacylisoquinolinium ylide reacts with aryl-methylenecyanothioacetamides differently, proceeding regio- and stereoselectively to give 4-aryl-2-hydroxy-3-(1-isoquinolinio)-2-phenyl-3-cyano-3,4-trans-1,2,3,4-tetrahydropyridine-6-thiolates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2593–2599, November, 1990.     

Synthesis of new halo-substituted pyrazolo[5,1-c][1,2,4]triazines

Ethyl 3-tert-butyl-4-oxo-7-X-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylates (X = H, Cl, Br) were synthesized for the first time by diazotization of 7-amino-3-tert-butyl-4oxo-8-ethoxycarbonyl-6H-pyrazolo[5,1-c][1,2,4]triazines with tert-butyl nitrite in the presence of trimethylsilyl halides. A new method was developed: a reaction between 7-amino-3-tert-butyl-4-oxo-6H-pyrazolo[5,1-c][1,2,4]triazine-8-carboxylic acid and I₂/TEA followed by treatment with NaBH₄ led to a mild decarboxylation. The acid reacts with N-halosuccinimides to give novel 8-halo-substituted derivatives. The amino groups of the latter were acylated by treatment with trifluoroacetic anhydride to give monoacylation products.