Trifluorination

The trifluorinated a, J-ethylenic ketone shown in equation 36 was prepared by two different methods and behaves like a Michael addition acceptor in reactions... 

Samples of l,l,l-trifhioro-2,2-bis(p-fluorophenyl)-ethane, and the corresponding bis-(p-chlorophenyl) derivative were obtained by applying Henne s fluorination method to DFDT and DDT, respectively. In both instances a mixture of the mono-, di-, and trifluoro compounds was obtained, but the desired trifluorinated material was separated by fractional recrystallization from methanol and cooling with a mixture of dry ice and acetone. 

In contrast to the toxicity of these fluorinated oxygen and nitrogen-containing compounds, the products from trifluorinated methyl ketones and amines are reported to have low acute toxicities 62). The fluorocarbons are insoluble in water, alcohol, and hydrocarbons 38). 

The antitumor activities of mono-, di-, and trifluorinated analogues of retinoic acids on the polyenic chain, and also of some aromatic analogues, have been evaluated on mice papillomas. Some of these compounds exhibit superior activities to nonfluori-nated analogues. ... 

Trifluorinated analogues of monomorin, an indolizidin-type alkaloid that is an ant pheromone,and of vincamine derivatives have been described (Figure 4.54). ... 

The trifluorinated a./ -unsaturatcd ketone 43 can be prepared by two different methods and behaves like a Michael addition acceptor in reaction with nucleophilic species.1 Is reaction with an enamine gives an annulation product 44. This sequence constitutes a method to build up a ring bearing a trifluoromethyl group. 

Trifluoro-ABA (28) was synthesized from the methyl ester of trifluorinated P-ionylideneacetic acid, which was prepared by the method reported for the synthesis of 16,16,16-trifluororetinal [71,72], More... 

The substitution of Abu for leucine in the hydrophobic core position a9 shows that a significant decrease in spatial demand and hydrophobicity that thermally destabilizes the folding motif also reduces the rate of product formation. The y-di- and trifluorination of Abu further decelerates rather than accelerates the reaction. This trend correlates with the number of fluorine atoms within the side-chain. Interestingly, the same kind of... 

Budisa, N., Pipitone, O., Siwanowicz, I., et al. (2004) Efforts towards the design of teflon proteins in vivo translation with trifluorinated leucine and methionine analogues. Chemistry Biodiversity, 1(10), 1465-1475. 

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