Synthesis and alkylation ofN-methylmorpholinium 6-amino-3,5-dicyano-4-methylpyridine-2-thiolate

The condensation of acetaldehyde with a twofold excess of cyanothioacetamide andN-methylmorpholine givesN-methylmorpholinium 6-amino-3,5-dicyano-4-methylpyridine-2-thiolate. This compound is also formed by recyclization of 2,6-diamino-3,5-dicyano-4-methyl-4H-thiopyran. From this pyridinethiolate, several substituted 2-alkylthiopyridines and 3,6-diamino-5-cyano-4-methyl-2-methoxycarbonylthieno[2,3-b]pyridine were obtained.     

Catalytic oxidation of cycloalkane heteroanalogs as a way to polyfunctional compounds

Liquid phase oxidation of cycloalkane diheteroanalogs catalyzed by compounds of Cu²⁺, Ni²⁺, Co²⁺, Cr³⁺, Fe³⁺ has been studied. It has been established that these catalysts can be applied to intensify, oxidize and increase the selectivity of this process.

---

: Cu², Ni²⁺, Co²⁺, Cr³⁺, Fe³⁺. .

     

Synthesis and the reactions of trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines

The coupling of trifluoromethylated 1,3-diketones with (het)aryldiazonium chlorides results mainly in the formation of 1,2,3-triketones 2-(het)arylhydrazones while using hetarylamine with a NH-group at the α-position of the heterocycle as the diazonium component gives 4,7-dihydroazolo[5,1-c]triazines due to cyclization at the trifluoroacetyl fragment. Trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 7-hydroxy-4,7-dihydroazolo[5,1-c]triazines react regio-selectively with methyl hydrazine and phenyl hydrazine to form 3-CF₃-pyrazoles. The long-range coupling constants (J_F-H) of 1-methylpyrazoles and the chemical shifts of trifluoromethyl groups in the ¹⁹F NMR spectra can be used for the determination of regio-isomeric structures of mono(trifluoromethyl)-substituted pyrazoles. 2-(Het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines with two trifluoromethyl substituents afford the mixtures of cis- and trans-azopyrazoles in the reactions with hydrazines.     

Synthesis and properties of N-methylmorpholinium 6-methyl-4-(4-pyridyl)-5-phenylcarbamoyl-3-cyano-1,4-dihydropyridine-2-thiolate

Condensation of acetoacetic acid anilide, 4-pyridyl aldehyde, cyanothioacetamide and N-methylmorpholine gave N-methylmorpholinium 6-methyl-4-(4-pyridyl)-5-phenylcarbamoyl-3-cyano-1,4-dihydropyridine-2-thiolate from which were obtained the corresponding substituted pyridinethiones, 2-alkylthio-1,4-dihydropyridines and 3-amino-2-benzoyl-6-methyl-4-(4-pyridyl)-5-phenylcarbamoylthieno[2,3-b]pyridine.T. G. Shevchenko Lugansk Pedagogical Institute, Lugansk 348011. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 672–675, May, 1997.     

Synthesis and regioselectivity of the [3,3]-sigmatropic rearrangement of substituted 2-allylthio- and 2-allylseleno-1,4-dihydropyridines

The reaction of 3-cyano-1,4-dihydropyridine-2-thiolates and the corresponding selenolates with allyl bromide gave 2-allylthio- and 2-allylseleno-3-cyano-1,4-dihydropyridines, which, upon heating in various solvents or in the solid state, undergo [3,3]-sigmatropic rearrangement to give 3-cyano-3-allyl-1,2,3,4-tetrahydropyridine-2-thiones and the corresponding selenones. The resultant pyridinethiones are alkylated by alkyl halides at the sulfur atom and are oxidized by iodine to give disulfides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1888–1895, August, 1991.     

Synthesis of functionalized tetrahydropyridones by the tandem Knoevenagel—Michael—intramolecular ammonolysis—alkylation reaction

Russian Chemical Bulletin - The tandem Knoevenagel—Michael—intramolecular ammonolysis—alkylation reaction was used to synthesize functionalized tetrahydropyridones. The molecular...     

New Multicomponent Synthesis of Functionalized Nitriles and Esters of 6-Alkylsulfanyl-1,4-dihydronicotinic Acids

The multicomponent condensation of malononitrile, hydrogen sulfide, aryl or hetaryl aldehydes, 1,3-dicarbonyl compounds and alkylating reagents afforded functionalized nitriles and esters of 6-alkylsulfanyl-1,4-dihydronicotinic acids, their aromatic analogues and 1,4-dihydrothieno[2,3-b]pyridines.     

2-Acylcycloalkanones in Organic Synthesis

Russian Journal of Organic Chemistry - The review systematizes published data on the use of 2-acylcycloalkanones in organic synthesis. The data are arranged in accordance with the type of products...     

Modulation instability of Stokes wave → freak wave

Formation of waves of large amplitude (freak waves, killer waves) at the surface of the ocean is studied numerically. We have observed that freak waves have the same ratio of the wave height to the wave length as limiting Stokes waves. When a freak wave reaches this limiting state, it breaks. The physical mechanism of freak wave formation is discussed.     

N,N,N′-Trialkyl-1,8-diaminonaphthalenes: convenient method of preparation from protonated proton sponges and the first X-ray information

A simple procedure for the synthesis of N,N,N′-trialkyl-1,8-diaminonaphthalenes is described. It consists in partial demethylation (dealkylation) of commercially available proton sponge [1,8-bis(dimethylamino)naphthalene] and some of its derivatives at heating with HBr-KI-DMF system. Limitation, scope and a possible mechanistic pathway for the reaction are discussed. For isomeric 8-dimethylamino-1-methylamino- and 1-dimethylamino-8-methylamino-4-nitronaphthalenes, X-ray measurements have been conducted. The first examples of complete realkylation reactions in the naphthalene proton sponges are reported.