Search

Hydrochloric acid reacts with 5-ethyl-2-methallylsulfanyl-6-methylpyrimidin-4(3 H)-ones to protonate the nitrogen atom; it adds to the double bond of 2-prenylsulfanyl-6-(trifluoromethyl)pyrimidin-4(3 H)-one and gives the addition and heterocyclization products in the case of 2-prenylsulfanyl-6-methylpyrimidin-4(3 H)-one. [ABSTRACT FROM AUTHOR]

Multicomponent reactions of ethyl 1-trifluoromethyl-2-(trimethylsilyloxy)cyclopropanecarboxylate, isonitriles, and either 2-aminopyridine or amino acids provided imidazo[1,2- a]pyridines or γ-lactams, respectively. This access to trifluoromethyl-substituted heterocycles demonstrates again that siloxycyclopropanes can serve as hidden functionalized aldehydes and that this type of donor-acceptor-substituted cyclopropanes is particularly versatile. [ABSTRACT FROM AUTHOR]

An improved procedure was developed for the synthesis of 3,3,3-trifluoro-1-nitropropene, and a new representative of gem-bromonitroalkenes, 1-bromo-3,3,3-trifluoro-1-nitropropene, was synthesized therefrom. Its reaction with phenyl azide gave a mixture of two regioisomeric 1,2,3-triazoles, from which pure 5-nitro-1-phenyl-4-(trifluoromethyl)-1 H-1,2,3-triazole was isolated. [ABSTRACT FROM AUTHOR]

A method is proposed for the synthesis of 3-nitro-2-phenyl-2-(trifluoromethyl)-2 H-chromenes by tandem condensation of salicylic aldehydes with ( E)-3,3,3-trifluoro-1-nitro-2-phenylprop-1-ene in the presence of triethylamine. The example of 3-nitro-2-phenyl-2-(trifluoromethyl)-2 H-chromene was used to demonstrate conjugated addition reactions with enamines, nitromethane, and aniline, which are characteristic for this class of compounds. The structure of the obtained products was confirmed by X-ray structural analysis. [ABSTRACT FROM AUTHOR]

1,1,1-Trifluoro-4-phenylbut-3-yn-2-one reacts with diphenyldiazomethane at 20°С in ethyl ether to afford 4-(trifluoromethyl)-1,1,6,6-tetraphenyl-4,6-dihydro-1 H-benz[5,6]oxepino[4,5- c]pyrazole. The process involves a stage of [3+2]-cycloaddition of the reagents, and the arising 3 H-pyrazole subsequently enters in an uncommon [3+6]-cycloaddition with 1 more molecule of diphenyldiazomethane. Further the formed diadduct of the initial acetylene suffers a 1,5-hydride shift and undergoes fragmentation with a loss of a nitrogen molecule thus converting into the final product. [ABSTRACT FROM AUTHOR]

The reactions of acetone, 2,2,2-trifluoroacetone and hexafluoroacetone in methanesulfonic (MSA) and triflic acids (TFSA) with benzene have been studied at M06-2X/6-311+G(d,p) level using cluster-continuum model, where the carbonyl group is explicitly solvated by acid molecules. The introduction of a trifluoromethyl group into the ketone structure reduces the activation energy of the tetrahedral intermediates formation due to an increase of the electrophilicity of the carbonyl group and raises the activation and the reaction energies of the C-O bond cleavage in formed carbinol due to the destabilization of the corresponding carbocation. The introduction of the second trifluoromethyl group inhibits the hydroxyalkylation reaction due to a very strong increase of the reaction and activation energies of the C-O bond cleavage which becomes the rate determining step. The most important catalytic effect of TFSA compared to MSA is not the protonation of the ketone carbonyl, but the reduction of the activation and reaction energies of the carbinol C-O bond cleavage due to better protosolvation properties. Even for TFSA no complete proton transfer to carbonyl oxygen has been observed for free ketones. Therefore, the protonation energies of free ketones cannot be considered as a measure of ketone reactivity in the hydroxyalkylation reaction. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]