Effect of fluorination

Substitution of fluorine into an organic molecule results in enhanced chemical stabiUty. The resulting chemical reactivity of adjacent functional groups is drastically altered due to the large inductive effect of fluorine. These effects become more pronounced as the degree of fluorine substitution is increased, especially on the same carbon atom. This effect demonstrates a maximum in fluorocarbons and their derivatives. 

Fluorinated Acids. This class of compounds is characterized by the strength of the fluorocarbon acids, eg, CF COOH, approaching that of mineral acids. This property results from the strong inductive effect of fluorine and is markedly less when the fluorocarbon group is moved away from the carbonyl group. Generally, their reactions are similar to organic acids and they find apphcations, particularly trifluoroacetic acid [76-05-1] and its anhydride [407-25-0] as promotors in the preparation of esters and ketones and in nitration reactions. 

Nonenzymatic fluorinated amino acids (182) have been developed by enzymatic and chemical methods as bioactive compounds siace the antiviral effect of fluorinated alanine was found (183). 

The effects of fluorination on solid-surface free energies parallel the liquid trends Perfluormated polymers have the lowest cntical surface tensions, which directly relate to their antistick properties [19], but substimtion of fluorine by hydrogen or by the more polarizable ehloiine atom markedly raises their surface free energy. 

Effects of Fluorine on the Biological Properties of Steroids and Terpenoids... 

Genther BRS, GT Townsend, PJ Chapman (1990) Effect of fluorinated analogues of phenol and hydroxyben-zoates on the anaerobic transformation of phenol to benzoate. Biodegradation 1 65-74. 

The fluorination of chromium oxide caused an increase of surface site Lewis acidity. Kemnitz and al.[12] as well as Peri [13], showed that on fluorinated alumina the progressive substitution of F for O and OH led, thanks to inductive attracting effect of fluorine, to an increase of the Lewis acidity of a sites. Hence the dehydrofluorination reaction was ftivoured on strong acide sites. 

Effect of Fluorine Substituents on the Acidity and Basicity of Compounds... 

EFFECTS OF FLUORINE ON PHARMACOKINETIC PARAMETERS AND DRUG-LIKE PROPERTIES... 

Table 2 Effects of fluorine on the properties of gamma-secretase inhibitors... 

Table 10 Effects of fluorine substitution on GABAa binding and efficacy...

Here, regioselective anodic substitutions of heteroatom compounds having fluoroalkyl groups and the effects of fluorine atoms on both the synthetic behavior and the oxidation potentials will be mainly discussed. 

Figure 16.3. Effect of fluorination time on surface tension of PE (10% F2/N2. 30°C. constant flow of 20 cm3/min).

Tablel6.13. Effect of Fluorinated and Unfluorinated Fibrillated PP Fibers on Certain...

In order to obtain some insight concerning the effect of fluorine on metabolic activation of fluorinated PAHs, isodesmic reactions (Figure 12) were calculated as a measure of the relative ease of formation of the fluorinated epoxides. Almost no energy differences were observed, consequently formation of these intermediates could be assumed not to be as relevant as carbocation formation in determining the relative reactivity of the ultimate metabolites. 

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