Tris trifiuoromethyl

Pyrazoles are formed when the diazo compounds react with alkynes or with functionalized alkenes, viz. the enols of /3-diketones. Pyrazolenines (353 Section 4.04.2.2.1) are isolated from disubstituted diazomethanes. Many pyrazoles, difficult to obtain by other methods, have been prepared by this procedure, for example 3-cyanopyrazole (616) is obtained from cyanoacetylene and diazomethane (7iJCS(C)2i47), 3,4,5-tris(trifiuoromethyl)pyrazole (617) from trifluorodiazoethane and hexafluoro-2-butyne (8lAHC(28)l), and 4-phenyl-3-triflylpyrazole (618 R =H) from phenyltriflylacetylene and diazomethane (82MI40402). An excess of diazomethane causes iV-methylation of the pyrazole (618 R = H) and the two isomers (618 R = Me) and (619) are formed in a ratio of 1 1. 

A solution of trifluoromethyl l,2,3-tris trifiuoromethyl)cycloprop-2-enyl ketone (119 mg) and excess pyrrole in pentane was sealed in a Pyrex tube. After 1 h at rt the contents of the tube were concentrated under vacuum and the residue was recrystallized from pentane to give compound 2 as colorless prisms yield 84 mg (56%) mp 78-79°C. 

In our laboratory, we find that the plasma reaction of trifiuoro-methyl radicals with mercuric iodide is an excellent source of bis(tri-fluoromethyDmercury. For those laboratories that lack access to radiofrequency (rf) equipment (a 100-W, rf source can at present be purchased for less than 1,000), synthesis of bis(trifluoromethyl)mercury by the thermal decarboxylation of (CFgCOjlzHg is also a functional, and quite convenient, source of bis(trifiuoromethyl)mercury (23). 

Attempts were made not only to find an alternative way to replace dimer and to deposit high-quality poly(tetrafluoro-p-xylylene) film, but also to eliminate the dibromide as the precursor because of the difficulty of synthesis. Therefore, the deposition of poly(tetrafluoro-p-xylylene) film by using hexafiuoro-p-xylene as the precursor instead of dibromotetrafluoro-p-xylene was tried. However, no polymer film was deposited on the wafer. Effort was expanded and other metal reagents such as nickel or copper were used to react with l,4-bis(trifiuoromethyl)-benzene to generate a,a,a, a -tetrafiuoro-p-xylylene to deposit poly(tetrafluoro-p-xylylene) film. However, the result showed that no film was deposited, which was not unexpected, because a C—bond that is weaker than C— F bonding might be necessary to initiate the formation of the desired intermediate. 

Octene 2.5-Bis-[trifiuoromethyl]-dodeciifluoro-3-(fltioro-tris-[diethylamino]-phosphoranyl)-3-(pentalIuoro-cthyl)- ElOb,. 431 [2-CF,-F9-2-penten + P(NR,)3]... 

Other examples of favored formation of cyclobutanes include photocycloadditions of tri-fiuoromethyl-substituted coumarins with dienes,144 and of 5-(trifiuoromethyl)-l, 3-dioxin-4-ones, e.g. 3, with alkenes,145-146 as well as intramolecular photocycloadditions, such as those of bicyclo[2.2.2]octadiene and tricyclononadiene derivatives.147148... 

The photochemical elimination of larger molecule fragments has also been described. 1,2,4,6,7-Pentakis(trifluoromethyl)-3,5-diazatricyclo[4.1.0.02 7]hept-3-ene can be converted photochemi-cally to its bicyclic isomer, 1,3,5,6,7-pentakis(trifiuoromethyl)-2,4-diazabicyclo[3.2.0]hepta-2,6-diene (7). This can be cleaved by irradiation with a low-pressure mercury lamp to give 2.4,5-tris(trifluoromethy )imidazole (8) with loss of hexafluorobutyne.125... 

The pifa of j -(trifIuoromethyl)benzoic acid is 3.6. Would you expect the tri-fluoromethyl substituent to be an activating or deactivating group in the Friedel-Crafts reaction ... 

Bis-[4-melhyl-phcnyll 3-(2.2,2-tri-fluoro-l-trifiuoromethyl-eihyli-denc)- 2961... 

C — Br and C —I bond polarization in perfiuoroalkyl- and polyfluoroaryl-containing derivatives may be promoted by reagents other than phosphorus derivatives. When tetrakis-(dimethylamino)cthene is treated with bromotrifiuoromethane or trifluoroiodomethane in the presence of chlorotrimethylsilane under similar conditions24 only traces of trimethyl(tri(luoro-methyl)silane are obtained, but dimethylbis(trifiuoromethyl)silane can be prepared from trifiuo-roiodomethane and dichlorodimethylsilane in 63% yield.35... 

Full details of the synthesis and characterization of bis(trifiuoromethyl)-thiophosphoryl-/i-thio-bis(trifluoromethyl)phosphine (60) and bis[bis(tri-fluoromethyl)thiophosphoryl] disulphide (61) (see Scheme 41) are published a similar situation exists for bis(trifluoromethyl)thiophosphinic acid and its anhydride (see Scheme 42), and for trimethylsilyl esters of trifluoromethyl-substituted phosphorus acids (see Scheme 43). - Also... 

Table 5.43 shows the results of a number of copolymerization runs of vinylidene fluoride and 3,3,3-tri-fiuoro-2-trifiuoromethyl propene in a solvent medium. 

---