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.     

Alkylation of 2-(methylsulfanyl)-6-polyfluoroalkylpyrimidin-4(3<Emphasis Type="Italic">H</Emphasis>)-ones with haloalkanes

The alkylation of ambident anions of 2-(methylsulfanyl)-6-(polyfluoroalkyl)pyrimidin-4(3H)-ones with 4-bromobutyl acetate leads to concurrent formation of O- and N-(4-acetoxybutyl) derivatives. Polar aprotic solvents favor formation of the O-isomer, and weakly polar dioxane favors N-alkylation. The reaction of 2-(methylsulfanyl)-6-(trifluoromethyl)pyrimidin-4(3H)-one with an equimolar amount of 1,2-dibromoethane in polar acetonitrile gives a mixture of N,N-, O,O-, and N,O-bridged bis-pyrimidines, as well as N- and O-[2-(methylsulfanyl)ethyl] derivatives, whereas in the presence of 10 equiv of 1,2-dibromoethane the N,O-isomer is formed as the only product. The reaction in weakly polar tetrahydrofuran yields N,N- and N,O-bispyrimidines.     

Synthesis of polyfluoroalkyl-containing 1-(4-acetoxybutyl)- and 1-(4-hydroxybutyl)pyrazoles and their tuberculostatic activity

Alkylation of polyfluoroalkyl-containing pyrazoles with 4-bromobutyl acetate in acetone in the presence of potassium carbonate leads to a mixture of isomeric 1-(4-acetoxybutyl)-3-fluoroalkyl- and 1-(4-acetoxybutyl)-5-fluoroalkylpyrazoles, which in a number of cases were successfully separated by HPLC. Deacylation in acidic medium with gaseous hydrogen chloride and in basic medium with gaseous ammonia leads to 1-(4-hydroxybutyl)pyrazoles, which manifest moderate tuberculostatic activity.     

One-pot synthesis of 5-fluoroalkyl-5-hydroxy-4-hydroxy-imino-1-isonicotinoyl-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazoles and their tuberculostatic activity

5-Fluoroalkyl-5-hydroxy-4-hydroxyimino-1-isonicotinoyl-4,5-dihydro-1H-pyrazoles were synthesized via a one-pot procedure from polyfluoroalkyl-containing 1,3-diketones, sodium nitrite in acetic acid, and isoniazid. Acetylacetone gave rise to 3-hydroxyiminopentane-2,4-dione monoisonicotinoylhydrazone which underwent intramolecular cyclization to 5-hydroxy-4-hydroxyimino-1-isonicotinoyl-3,5-dimethyl-4,5-dihydro-1H-pyrazole on heating in ethanol. The synthesized compounds exhibited moderate tuberculostatic activity.     

Alkylation of 6-Polyfluoroalkyl-2-thiouracils with Haloalkanes

Russian Journal of Organic Chemistry - The structure of 6-polyfluoroalkyl-2-thiouracils and reactivity of nucleophilic centers in their molecules were analyzed by quantum chemical calculations....     

6-Trifluoromethyl-2-thiouracil and its analogs in reactions with 4-bromobutyl acetate and 2-bromoacetophenone

Russian Chemical Bulletin - The alkylation of 6-(polyfluoro)alkyl-2-thiouracils with 4-bromobutyl acetate in refluxing acetonitrile in the presence of K2CO3 proceeds regioselectively to give S,...     

Fluoroalkyl-containing 2-arylhydrazono-1,3-dicarbonyl compounds in the reactions with ethylenediamine and polyethylenepolyamines

Acyclic N,N′-(poly)ethylene-bis(2-arylazo-1,3-aminovinylketones) are the main products in the reactions of fluoroalkyl-containing 2-arylhydrazono-1,3-diketones with ethylenediamine, diethylenetriamine and triethylenetetramine. Nickel(II) and copper(II) chelates were obtained from N,N′-ethylene-bis(2-arylazo-1,3-aminovinylketones). 2-Arylhydrazono-3-fluoroacyl esters formed N,N′-ethylenediamides of 2-arylhydrazono-3-fluoroacylpropionic acids with ethylenediamine. Interaction of 2-arylhydrazono-3-fluoroacyl esters with diethylenetriamine and triethylenetetramine resulted in and decomposition products.     

Synthesis of regioisomeric N- and O-alkylated 3-polyfluoroalkyl-1,2-dihydroquinoxalin-2-ones

3-Polyfluoroalkyl-1,2-dihydroquinoxalin-2-ones react with 4-bromobutyl acetate to furnish 1-(4-acetoxybutyl)quinoxalin-2-ones and 2-(4-acetoxybutoxy)quinoxalines in the ratio 2: 1. Deacylation of these compounds under acidic conditions gives the corresponding 1-(4-hydroxybutyl)- and 2-(4-hydroxybutoxy)-substituted quinoxalines. The structures of compounds synthesized were established by X-ray crystallography, IR spectroscopy, ¹H and ¹⁹F NMR spectroscopy, GLC-MS.