3-Polyfluoroalkyl-1,5-diphenylpyrazoles in Suzuki Cross-Coupling Reactions

Russian Journal of Organic Chemistry - Suzuki cross-coupling was used for modification of 3-polyfluoroalkyl-1-phenylpyrazoles at the position C4. The synthesized 4-bromo- and 4-phenyl derivatives...     

Cyclization of fluoroalkyl-containing 1,3-dicarbonyl compounds with ethylenediamine hydroperchlorate to 1,4-diazepines

2,3-Dihydro-1H-1,4-diazepines and 1,2,3,4-tetrahydro-1,4-diazepin-5-ones were obtained by direct condensation of fluorine-containing 1,3-diketones and 1,3-keto ethers, respectively, with ethylenediamine monohydroperchlorate. The structure of the compounds was confirmed by¹H NMR, mass spectrometry and molecular weight determination.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 890–896, April, 1991.     

Methyl mercapturate synthesis: an efficient, convenient and simple method

A safe and simple method for methyl S-arylmercapturate synthesis is described. Thirteen such compounds, to be used afterwards in metabolism studies, have been obtained with yields ranging from 71 to 99.6%. These compounds were obtained using a sulfa-Michael addition and synthesized by adding the corresponding thiophenols to a mixture composed of methyl 2-acetamidoacrylate (MAA), potassium carbonate and a phase transfer catalyst, Aliquat 336. MAA, the initial synthon, was itself isolated in quasi quantitative yield following a fully described synthesis.     

Synthesis of pyrimidine derivatives based on ethyl 2-ethoxymethylidene-3-polyfluoroalkyl-3-oxopropionates and urea

Russian Chemical Bulletin - Ethyl 2-ethoxymethylidene-3-polyfluoroalkyl-3-oxopropionates under mild conditions undergo regioselective condensation with urea at the ethoxymethylidene substituent...     

Catalyst-free transformations of diethyl 2-ethoxymethylenemalonate and diethyl polyfluorobenzoylmalonates in water

The unusual transformation of diethyl 2-ethoxymethylenemalonate into triethyl 1,3,5-benzenetricarboxylate is described. This one-pot reaction proceeds in water without any catalyst in a good yield. One of the proposed intermediates of this process is also used under similar conditions to give the desired trisubstituted benzene. A catalyst-free, efficient, practical, and convenient process in water based on deethoxycarbonylation has been developed to form ethyl polyfluorobenzoylacetates in a high yield from diethyl polyfluorobenzoylmalonates.     

Synthesis of derivatives of pyrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines and imidazo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines proceeding from alkyl 2-benzylidene-3-oxo-3-fluoroalkylpropionates

Methods were developed of the synthesis of alkyl 2-hydroxy-2-fluoroalkyl-4-phenyl-1,2,3,4—tetrahydroimidazo-[1,5-a]pyrimidine-3-carboxylates and alkyl-5-hydroxy-2,7-diphenyl-5-fluoroalkyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-6-carboxylates by regioselective [3+3]-cycloaddition of 5-aminoimidazole or 5-aminopyrazole to alkyl 2-benzylidene-3-oxo-3-fluoroalkylpropionates at the fluoroacylvinyl fragment.     

Steric structure of alkyl 2-aryl(hetaryl)hydrazono-3-fluoroalkyl-3-oxopropionates

Steric structure of fluorinated 2-arylhydrazono-3-oxo esters was studied by ¹H, ¹⁹F, and ¹³C NMR spectroscopy and X-ray analysis. It was found that these compounds in the crystalline state and in solutions in acetone-d ₆, DMSO-d ₆, and CDCl₃ exist as Z isomers with the ester fragment involved in intramolecular hydrogen bond with the hydrazone NH proton. Exceptions are alkyl 2-arylhydrazono-4,4-difluoro-3-oxobutanoates which exist in acetone-d ₆ as mixtures of Z and E isomers, the former prevailing. Unlike fluorinated analogs, ethyl 2-(4-methylphenyl)hydrazono-3-oxobutanoate in crystal has the structure of E isomer in which intramolecular hydrogen bond is formed between the NH proton and acetyl carbonyl group. The same compound in acetone-d ₆, DMSO-d ₆, and CDCl₃ gives rise to a mixture of Z and E isomers, the latter prevailing.     

Synthesis of pyrimido[1,2-a]benzimidazoles from ethyl 2-ethoxymethylidene-3-oxo-3-(polyfluoroalkyl)propionates

Cyclization of ethyl 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates with benzimidazol-2-amine in boiling 1,4-dioxane followed two concurrent pathways with participation of fluoroacyl and ethoxycarbonyl fragments and formation of, respectively, ethyl 4-hydroxy-4-polyfluoroalkyl-1,4-dihydropyrimido-[1,2-a]benzimidazole-3-carboxylates and 3-polyfluoroacylpyrimido[1,2-a]benzimidazol-4-ols. Dihydropyrimido[1,2-a]benzimidazole derivatives undergo dehydration to give ethyl 4-(polyfluoroalkyl)pyrimido[1,2-a]benzimidazole-3-carboxylates, whereas the hydroxy group in 3-polyfluoroacylpyrimido[1,2-a]benzimidazol-4-ols is capable of being replaced by the amino group of the second benzimidazole molecule with formation of 4-(1H-benzimidazol-2-ylamino)-3-polyfluoroacylpyrimido[1,2-a]benzimidazoles.     

Reaction of fluoroalkyl-containing 1,3-dicarbonyl compounds with benzylideneacetone

The reaction of fluoroalkyl-containing 1,3-dicarbonyl compounds with benzylideneacetone with the use of pyridine or triethylamine as a catalyst gave new 3-fluoroalkyl-4-ethoxycarbonyl(acyl)-5-phenylcyclohexan-3-ol-I-ones in yields of 16–33%. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 992–994, May, 1997.