[2+2] Cycloaddition and electrophilic alkynylation reactions of 4-chloro-1,1,1-trifluorobut-3-yn-2-one and alkyl vinyl ethers

Reaction of 4-chloro-1,1,1-trifluorobut-3-yn-2-one with alkyl vinyl ethers leads to the parallel formation of [2+2] cycloaddition and electrophilic alkynylation products, the ratio of which depends on the nature of vinyl ether. Preparative methods for the separation of compounds formed are suggested.     

Synthesis of trifluoromethyl-substituted salicylates by cyclocondensation of 1,3-bis(silyloxy)-1,3-butadienes with 4,4-dimethylthio-1,1,1-trifluorobut-3-en-2-one

A formal [3+3] cyclocondensation of 1,3-bis(silyl enol ethers) with the little-known 4,4-dimethylthio-1,1,1-trifluorobut-3-en-2-one was studied. In contrast to 4,4-dimethoxy-1,1,1-trifluorobut-3-en-2-one, this α-oxoketene dithioacetal reacts with 1,3-bis(trimethylsilyloxy)-1,3-butadienes in the presence of TiCl₄ to give mainly 6-methylthio-4-(trifluoromethyl)salicylates via 1,2-addition. The scope and limitations of the reaction are discussed.     

Product of uncommon reaction of 1,1,1-trifluoro-4-phenylbut-3-yn-2-one with diphenyldiazomethane

Russian Journal of Organic Chemistry - 1,1,1-Trifluoro-4-phenylbut-3-yn-2-one reacts with diphenyldiazomethane at 20°С in ethyl ether to afford...     

Regioselective synthesis of 1-aryl-4-bromo-5-trifluoromethylpyrazoles

A novel regioselective route to 1-aryl-4-bromo-5-trifluoromethylpyrazoles involves reactions of arylhydrazines with 3-bromo-4-ethoxy-1,1,1-trifluorobut-3-en-2-one. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 167–168, January, 2006.     

Oxidation of aromatic compounds: XIV. Oxidation of arylethynyl ketones in the system CF3CO2H-CH2Cl2-PbO2

Oxidation of arylethynyl ketones ArC≡CCOCX₃ (X=H, F) in the system CF₃CO₂H-CH₂Cl₂-PbO₂ was studied on a preparative scale. The oxidation of 4-arylbut-3-yn-2-ones (X=H) involves transfer in total of four electrons, leading to (E)-3,4-bis(arylcarbonyl)hex-3-ene-2,5-diones. 4-Aryl-1,1,1-trifluorobut-3-yn-2-ones (X=F) are oxidized with transfer of only two electrons to produce 2-aryl-4-arylcarbonyl-5-trifluoromethyl-3-trifluoroacetylfurans. Possible mechanisms of radical-cation transformations of arylethynyl ketones into the final products are discussed.     

Synthesis of Trifluoromethylated 3-(3-Pyrazolyl)indole-N-glycosides and their Cytotoxic Activity against Human Keratinocytes (HaCaT)

The first 3-(3-pyrazolyl)indole-N-glycosides were prepared starting from indole-N-glycosides by conversion with 4-ethoxy-1,1,1-trifluorobut-3-en-2-one and following cyclization with hydrazine. The cytotoxic activity of the products against human keratinocytes (HaCaT) was studied.     

Synthesis and structure of trifluoromethylated arylhydrazones formed from coupling of 4-(dimethylamino)-1,1,1-trifluorobut-3-en-2-one with diazonium salts

A series of trifluoromethyl-containing arylhydrazones were prepared via a direct azo-coupling of (E)-4-(dimethylamino)-1,1,1-trifluorobut-3-en-2-one (1) with different aromatic diazonium salts. Furthermore, we also discussed the non-covalent interactions existing in the crystal structure of compound (E)-4,4,4-trifluoro-2-(2-(4-iodophenyl)hydrazono)-3-oxobutanal (3c) by the X-ray diffraction analysis.     

Reaction of trifluoromethyl-containing 1,3-dicarbonyl compounds with bis-hydrazides

Carbonic dihydrazide reacted with 2 equiv of trifluoroacetylacetone to give a compound containing 5-hydroxy-4,5-dihydropyrazole and keto enehydrazine fragments. Analogous 2 : 1 condensations of trifluoro-acetylacetone and 4-ethoxy-1,1,1-trifluorobut-3-en-2-one with oxalohydrazide and malonohydrazide afforded bis(5-hydroxy-4,5-dihydropyrazole) structures as two diastereoisomers.     

Reactions of 4-ethoxy-1,1,1-trifluorobut-3-en-2-one with diethyl malonate anion: synthesis and crystal structures of fluorinated organo alkali–metal complexes

At room temperature, 4-ethoxy-1,1,1-trifluorobut-3-en-2-one reacted with alkali metal salts of diethyl malonate to give two kinds of complexes. One is the solvent molecule-involved complexes, and the other is a sheer ion aggregates composed by alkali metal cation and carbanion. Both crystals are fully characterized by spectroscopic methods and single crystal X-ray diffraction analyses.     

One-Pot Synthesis of Diethyl 2-Aryl-3-(trifluoroacetyl)-cyclopropane-1,1-dicarboxylates

Russian Journal of Organic Chemistry - The reaction of 4-aryl-3-bromo-1,1,1-trifluorobut-3-en-2-ones with diethyl malonate afforded diethyl 2-aryl-3-(trifluoroacetyl)cyclopropane-1,1-dicarboxylates...     

Furan forming reactions of cis-2-alken-4-yn-1-ones

[reactions: see text] The cis-2-alken-4-yn-1-one, 1-phenyl-cis-2-penten-4-yn-1-one (cis-1), readily dimerizes on treatment with weak acid to give the 1,2-difurylethylenes, trans- and cis-1,2 di(2-(5-phenylfuryl))ethene (trans-1 and cis-2), in 62% and 23% yields, respectively. Trimerization of cis-1 to trans,trans-1,2,3-tri(2-(5-phenylfuryl)cyclopropane (4) occurred as a byproduct of treatment with weak acid. These reactions demonstrate the 2-furylcarbenoid reactivity of cis-2-alken-4-yn-1-ones.     

Reactions of tri- and hexafluoroacetylacetones and 4-ethoxy-1,1,1-trifluorobut-3-en-2-one with 2-aminobenzohydrazide

Reactions of 1,1,1-trifluoropentane-2,4-dione and 1,1,1,5,5,5-hexafluoropentane-2,4-dione with 2-aminobenzohydrazide afforded (2-aminophenyl)[5-hydroxy-3-methyl-5-(trifluoromethyl)- and (2-aminophenyl)[ 5-hydroxy-3,5-bis(trifluoromethyl)-4,5-dihydropyrazol-1-yl]methanones, respectively. 4-Ethoxy-1,1,1- trifluorobut-3-en-2-one reacted with 2-aminobenzhydrazide to give 2-(trifluoromethyl)-3a,4-dihydropyrazolo-[5,1-{ptb}]quinazolin-9(3{ptH})-one.     

Synthesis of 3-[5-(biphenyl-4-yl)pyrrol-2-yl]-1-phenylprop-2-yn-1-ones by palladium-free cross-coupling between pyrroles and haloalkynes on aluminum oxide

Cross-coupling of 2-(biphenyl-4-yl)pyrroles derived from 1-(biphenyl-4-yl)ethanone oximes and acetylene with 3-bromo-1-phenylprop-2-yn-1-one on aluminum oxide gave 3-[5-(biphe-nyl-4-yl)pyrrol-2-yl]-1-phenylprop-2-yn-1-ones in 35–46% yields.     

Reaction of 1,5-Diphenyl-1,4-pentadien-3-one and 1,5-Diphenyl- 1-penten-4-yn-3-one with Monosubstituted Hydrazines

Phenyl- and isopropylhydrazines react with 1,5-diphenyl-1,4-pentadien-3-one to give 4,5,6,7-tetrahydroindazole derivatives instead of the expected 4,5-dihydropyrazoles. The reaction of phenylhydrazine with 1,5-diphenyl-1-penten-4-yn-3-one leads to formation of 1,5-diphenyl-3-phenylethynyl-4,5-dihydropyrazole. 2,4-Dinitrophenylhydrazine reacts with 1,5-diphenyl-1-penten-4-yn-3-one, affording the corresponding unsaturated hydrazone rather than pyrazole derivative.     

Synthesis of 1,1,1 - trifluoro-2-penten-4-one

The 1,1,1-trifluoro-2-penten-4-one has been prepared from trifluoroacetaldehyde by two different ways. Its condensation with a cyclohexanone enamine leads, by annelation, to 4-trifluoromethyl-Δ-1,9 (and Δ-9,10)-octalin- 2-one.     

One-pot Synthesis of 4-Trifluoromethyl-l,2-dihydropyrimidines

4-Trifluoromethyl-1,2-dihydropyrimidines were synthesized in moderate yields by the one-pot reaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one, aldehydes and ammonia catalyzed by zinc chloride under mild conditions.     

The microbial hydroxylation of levonorgestrel

The microbial transformation of levonorgestrel (1) by Cunningham elegans resulted in the formation of five hydroxylated metabolites, 13-ethyl-10beta, 17beta-dihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one(2), 13-ethyl-6beta,17beta-dihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one (3) 13-ethyl 6beta, 10beta, 17beta-trihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one (4) 13-ethyl-15alpha-17beta-dihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one (5) and 13-ethyl-11alpha, 17beta-dihydroxy-18,19-dinor-17alpha-pregn-4en-20-yn-3-one. The fermentation of one with Rhizopus stolonifer, Fusarium lini and Curvularia lunata afforded compound 2 as a major metabolise. These metabolites were structurally characterized on the basis of spectroScopic techniques. Metabolite 6 was identified as a new compound. Compounds 2 2 ad 5 displayed inhibitory activity against the acetylcholinesterase ( AChE, EC. 3.1.1.7) with IC50 values of 79.2 and 24.5 microM, respectively. The metabolites 2 and 5 also showed inhibitory activity against the butyryLcholinesterase ( BChE, E.C 3.1.1.8) with IC50 values ranging between 9.4 and 309.8 microM.     

Novel Synthesis of 3,5,5-Trimethyl-4-(2-butenylidene)-cyclohex-2-en-1-one,a Major Constituent of Burley Tobacco Flavour

The acetylenic diol 2 , prepared by reaction of but-3-yn-2-ol dianion with 2,6,6-trimethyl-4,4-ethylenedioxy-cyclohex-2-en-1-one ( 1 ), afforded 3,5,5-trimethyl-4-(2-butenylidene)-cyclohex-2-en-1-one ( 4 ), a major constituent of Burley tobacco flavour, upon LiAlH₄ reduction and hydrolysis. Vomifoliol ( 5 ) and blumenol C ( 6 ) were major by-products in this reaction.     

Synthesis, structure and complexation of the fluorinated 1,3-enaminoketones containing at the nitrogen atom substituents with a terminal C≡C bond

The reaction of fluorinated lithium 1,3-diketonates with propargylamine hydrochloride and 1,1,1-trifluorpentane-2,4-dione or 1,1,1-trifluoro-4-methoxypent-3-en-2-one with propargylamine and 3-aminophenylacetylene were performed to obtain fluorinated 1,3-enaminones containing at a nitrogen atom substituents with terminal C≡C bonds: (Z)-1,1,1-trifluoro-4-(2-propynylamino)-3-pentene-2-one, (Z)-1,1,2,2-tetrafluoro-5-(2-propynylamino)-4-hexen-3-one, and 4-(3-ethynylphenylamino)-1,1,1-trifluoropentyl-3-en-2-one. Reactions of 4-(3-ethynyl-phenylamino)-1,1,1-trifluoro-pentyl-3-en-2-one with Cu(II) acetate or nanosized powder of copper or its oxides led to the respective chelate complex. The structure of (Z)-1,1,2,2-tetrafluoro-5-(2-propynylamino)-4-hexen-3-one and a copper complex of 4-(3-etinilphenylamino)-1,1,1-trifluoropenta-3-en-2-one was determined by XRD.     

Iodocyclization of trifluoromethylallenic phosphonates: an efficient approach to trifluoromethylated oxaphospholenes

α-Trifluoromethylallenic phosphonates were prepared by the reaction of diethyl chlorophosphite (DECP) and 4,4,4-trifluorobut-2-yn-1-ols in the presence of Et₃N. The iodocyclization of these fluorine-containing allenic phosphonates was achieved with iodine under mild conditions to give the corresponding trifluoromethylated oxaphospholenes in moderate to good yields.