2,4 ,6-trifluoro-benzophenone

Guo et al. [180] prepared a series of sulfonated poly(aryl ether ketone) copolymers (Br-SPAEKs) by nucleophilic aromatic substitution reaction based on (6F-BPA, A2 monomer), 4,4 -DFBP, unsulfonated B2 monomer), 3,3 -disodiumsulfonyl-4,4-difluoro-benzophenone (SDFBP, sulfonated B2 monomer), and 2,4, 6-trifluoro-benzophenone (TFBP, branched... 

Several comparative studies are available in the literature, which clearly shows that, according to the latest results, tetrafluoro-pheny/ azides (AZ), trifluoro-methyl-phenyl diazirines (DZR), and particularly benzophenone (BP) are the best choice (Scheme 3.). Diazocarbonyl compounds, which played a historically role in the evolution of PAL, can also be considered together with aryl-diazonium salts [6] (not shown). For aryl azides the more common unsubstituted photophore is presented. It should be noted that tetrafluoro-phenyl azides have an increased reactivity towards CH-groups and they do not rearrange. Other substituted phenyl azides can readily alter the excitation wavelength allowing the application of milder or differential photoactivation. 

Dichloro-l. 2.2-trifluoro-ethyl)-heptafluoro- E10b2. 144 (Eduet) 4.6-Diethy -l-hydroxy-2-methyl-l-(4-trifluoro-plienyl)- E17f., 637 (Cyclis. Benzophenone-Der.) 4.6 Diisopropyl-2.2-dimethyM-hydroxy-l-(4-trifluoromcthyl-phenyl)- E17f. 637 (Cyclis. Benzophenon-Dcr.)... 

Preparation by demethylation of 3-methoxy-4 -(trifluoro-methyl)benzophenone with refluxing pyridinium chloride for 90 min (72%) or with 48% hydrobromic acid [900]. Preparation by dealkylation of 4-(trifluoromethyl)-3 -ethoxybenzophenone with pyridinium bromide at 210° for 0.5 h [977]. 

Obtained by demethylation of 2-methoxy-4-(trifluoro-methyl)benzophenone with boron tribromide in methylene chloride at0° for 4 h [1484]. 

Figure 2.4 illustrates the MALDI-ToF-MS of poly-potassium-5-cyano-4-fluoro-2-octylphenolate in the presence of 4-fluoro-4 -trifluoro-methyl benzophenone in N,N-dimethyl imidazolidinone solvent at 150 °C. The spectrum contains two major distributions. The distribution in the lower mass range corresponds to the Ag adducts of polypotassium-5-cyano-4-fluoro-2-octylphenolate without the poly 4-fluoro-4 -trifluoro methyl benzophenone unit from step-growth conventional polycondensation. 

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