Fluorocompounds

Chemical formula fCF-CF -n Chemical functionality CF3 Molecular weight 10 -10  

Maximum use temp., °C 260 Loss on ignition, % traces Surface tension, mN/m 25.6 

Moisture content, % traces Water solubility, % none pH of water suspension 7 

Refractive index 1.376 Color white Dielectric constant 2.1 

Particle shape many shapes possible Crystal structure trigonal, triclinic, or orthorhombic  

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Compounds in which the presence of fluorine atoms enhances the efficiency and selectivity of the biological activity with respect to the nonfluorinated parent compounds. These fluorocompounds should have fewer unfavorable effects. Due to these features (safety of use, better bioavailability, reduced dose, minor toxicity, etc.), these compounds have replaced, sometimes entirely, the nonfluorinated compounds of the same class. Volatile anesthetics and fluoroquinolones can be cited as examples of this category. 

Trifluoroacetic acid is a most useful building block for a wide range of tri-fluorocompounds, particularly trifluoromethyl ketones [206]. Esters are useful... 

This section deals with fluorinated dienes and fluorinated dienophiles in which the fluorine atom(s) are attached directly to the double bond(s). The reason for highlighting work in this area is to show how there is a significant need for new methodology indeed, the formation of cyclic mono- or di-fluorocompounds remains the one significant area where building block chemistry is weak. 

BF3 acidified HF sufficiently to dissolve the difluorides of the (/-transition metals and the trifluorides of the lanthanides, while trifluorides of (/-transition metals and tetrafluorides required SbF5-HF or AsF5-HF for dissolution. Many of the metals dissolved readily in acidified HF. Evolution of H2 from BF3-HF solutions indicated oxidation of the metals by H2F+. SbF5-HF solutions usually oxidised metals without H2 evolution, Sb(V) being reduced to Sb(III), a factor which can adversely affect recovery of fluorides or fluorocomplexes from these solutions because of the relatively low volatility of Sb(III) fluorocompounds. 

Banks, R.E. Parker, A.J. Sharp, M.J. Smith, GE.Al-Fluorocompounds. V. Photochemical reactions of perfluoro-7/-fluoromorpholine, and its thermal decomposition preparation and properties of perfluoromorpholin-7/-oxyl. J. Chem. Soc., Perkin Trans. 1 1973, (1), 5-13. 

A variety of anthracyclines fluorinated in ring A have been reported. Glycosy-lation of fluorinated aglycones was used to make 8-fluorocompounds such as 17, whilst 10-fluoro-derivatives were prepared by modification of daunorubicin or idarubicin. Some C-4 epimers were also described. 8-Fluoroanthracyclines have also been the subject of a symposium report. ... 

A detailed investigation has been reported into the cleavage of 3 - 5 -uridyluridine to form the 2, 3 -cyclic phosphate, and its isomerization to 2 5 -uridyluridine. The hydrolysis of uridine 2 -, 3 - and 5 -phosphoromonothio-ates under acidic and neutral conditions has been investigated in mild acid only hydrolysis to uridine occurs, whilst at low pH desulfurization occurs in the cases of the 2 - and 3 -thioates. The same workers have also studied the kinetics of hydrolysis and desulfurization of the diastereomeric monothio-analogues of uridine 2, 3 -cyclic phosphate under neutral or acidic conditions desulfurization competes with phosphoester hydrolysis. The hydrolysis of the 2 -thionucleoside 3 -phosphate 267 (X=SH) has been studied the predominant reaction pathway at pH 13 is the formation of the 5-phosphate whilst at pH 7-10 mostly the 2, 3 -cyclic monothiophosphate was produced. The 2 -fluorocompound 267 (X=F), which has a C-3 -endo- conformation, underwent hydrolysis ten times faster than did the deoxycompound 267 PC=H). The kinetics of hydrolysis of thymidine 5 -boranomonophosphate (269) have been studied by NMR. It was found that 269 hydrolyses slowly to thymidine and [03P-BH3 ], with the latter hydrolysing even more slowly to phosphonate and boric acid. ... 

Most of the strong deviations between predictions and experiment are due to less common functional groups like silanes or fluorocompounds or due to high symmetry like adamantane and related compounds, which is difficult to cope with via a non3D... 

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