V. P. Kislyi

Regioselective synthesis and S-derivatization reactions of 4- and 6-trifluoromethyl-3-cyano-2(1H)-pyridinethiones

Abstract The regioselective synthesis of the title compounds was developed on the basis of condensation reactions of trifluoroacetylacetone and its methyl enacetal with cyanothioacetamide in the presence of bases. Thus, the condensation of trifluoroacetyl-acetone with cyanothioacetamide yields predominantly 4-trifluoromethyl-6-methyl-3-cyano-2(1H)-pyridinethiones, whereas the methyl enacetal of trifluoroacetylacetone gives exclusively the 6-trifluoromethyl-4-methyl isomer. S-Alkylation of the trifluoromethyl-pyridinethione salts can be achieved using methyl iodide or bromoacetophenone in DMF-water. Bromoacetophenone derivatives can be further transformed into 3-aminothieno-[2,3-b]pyridines in the presence of excess KOH.

Heterocycles with a β-nitroenamine fragment

Reactions of dimedone and dihydroesorcinol with arylidenenitroacetonitriles yield fused 2-amino-3-nitropyrans. The crystal and molecular structure of one of the reaction products was determined by X-ray diffraction analysis.

Synthesis of α-functional nitro compounds by the nitration of activated carbonyl compounds in a two-phase system

Abstract2-Nitro-1,3-dicarbonyl and α-nitromonocarbonyl compounds were synthesized in the yields varying from moderate (30 %) to nearly quantitative by the nitration of β-dicarbonyl compounds in a two-phase system: sulfuric/nitric acid mixture-chloroform at - 10÷10 °C. The use of phase transfer conditions made it possible to avoid the formation of furoxans as by-products and to simplify the isolation of products. This method is quite common for preparing various α-functional nitro compounds including those containing a CF3-group. Key words: nitration, α-functional nitro compounds.

HETEROCYCLES WITH A BETA -NITROENAMINE FRAGMENT. 2. SYNTHESIS OF 2-AMINO-3-NITROPYRANO3,2-CPYRANS AND 2-AMINO-3-NITROPYRANO3,2-CCHROMENES FROM NITROAC ETONITRILE

The reactions of 4-hydroxy-6-methyl-2-pyrone and 4-hydroxycoumarin with arylidenenitroacetonitriles result in 2-amino-3-nitropyrano[3,2-c]pyrans and 2-amino-3-nitropyrano [3,2-c]chromenes, respectively. The crystal and molecular structure of one of the compounds obtained was determined by X-ray diffraction analysis.

Synthesis of 3-amino-4-methyl-6-trifluoromethylthieno[2,3-b]pyridine-2-carboxanilide and its crystal and molecular structure

Abstract4-Methoxy-1,1,1-trifluoropent-3-en-2-one reacts with cyanothioacetamide to give 3-cyano-4-methyl-6-trifluoromethylpyridine-2(1H)-thione, which was transformed into 3-amino-4-methyl-6-trifluoromethylthieno[2,3-b]pyridine-2-carboxanilide by the reaction with chloroacetanilide. The crystal and molecular structure of the amide obtained was studied by X-ray analysis.

Anodic perfluoroalkylation of the enol acetate of ethyl acetoacetate

Electrochemical perfluoroalkylation of the enol acetate of ethyl acetoacetate was studied in the conditions of the Kolbe reaction. The yields of alkylation products depend on the competing adsorption of the enol acetate, the solvent, and perfluorocarboxylates on the surface of a platinum electrode.

Ethyl 2-nitroacetoacetate as a new synthetic equivalent of ethoxycarbonylnitrile oxide

It was shown that ethyl 2-nitroacetoacetate is a synthetic precursor of ethoxycarbonylnitrile oxide as well as of isoxazole- and isoxazoline-3-carboxylic acids and their esters. The elimination of acetic acid from ethyl 2-nitroacetoacetate occurs in a mixture of acetic acid and acetic anhydride in the presence of strong mineral acids,e.g., H2SO4, at room temperature and gives isoxazolines in yields of up to 85–91 %.

Aminoisoxazoles: Preparations and Utility in the Synthesis of Condensed Systems

Publisher Summary This chapter deals with the chemistry of aminoisoxazoles(AI), which is a subsection of isoxazole chemistry. The available amino group changes distinctly the properties and reactivity of the isoxazole ring, and some reactions and rearrangements that are unusual in isoxazole chemistry become typical. An amino group is convenient in combinatorial chemistry and facilitates the use of these compounds in modern drug discovery. The studies on AI have been mainly concerned with the biological activities and the preparation of fused heterocyclic systems, such as isoxazolopyridines, isoxazolopyrimidines, and isoxazolodiazepines. AI-based condensed heterocyclic systems are more biologically promising than AI themselves. Indeed, AI derivatives possess cytostatic, antibacterial, herbicidal, immunological, hypocholesterolemic, and anticonvulsant activities among other activities.

Synthesis of 6-mono- and 5,6-disubstituted 1,2,3-triazolo[4,5-d]pyrimidin-7-ones

The reactions of N-substituted 4-amino-3-benzyl-1,2,3-triazole-5-carboxamides with phosphorus oxochloride and dimethylformamide at 80 °C or with triethyl orthoacetate and acetic anhydride at 160 °C afforded 6-mono- or 5,6-disubstituted 1,2,3-triazolo[4.5-d]pyrimidin-7-ones in 30—85% and 65—90% yields, respectively.

Regioselective synthesis and properties of 3-cyano-6-methyl-4-trifluoromethylpyridine-2(1H)-thione. Molecular and crystal structure of 3-cyano-2-ethylthio-6-methyl-4-trifluoromethylpyridine

The reaction of trifluoroacetylacetone with cyanothioacetamide proceeded regioselectively to form 3-cyano-6-methyl-4-trifluoromethylpyridine-2(1H)-thione from which the corresponding 2-alkylthiopyridines and 3-aminothieno[2,3-b]pyridines were obtained. The crystal and molecular structure of 3-cyano-2-ethylthio-6-methyl-4-trifluoromethylpyridine was established by X-ray diffraction analysis.