Biphenyl fluorination

Fluorinated biphenyls have been incorporated into numerous Hquid crystal stmctures as attested by patents and pubHcations from the following organizations E. Merck GmbH (257,258) Sharp (258) Hoffmann-LaRoche (259) Kanto Chemical (260) U.K. Defence Secretariat (261) Dainippon (262) Chisso (263) Sanyo Chemical (264) and the University of Hull (265). Seiko Epson has also patented fluorinated terphenyls for Hquid crystal appHcations (266). 

Properties have been determined for a series of block copolymers based on poly[3,3-bis(ethoxymethyl)oxetane] and poly [3,3-bis(methoxymethyl)oxetane]- (9-tetrahydrofuran. The block copolymers had properties suggestive of a thermoplastic elastomer (308). POX was a good main chain for a weU-developed smectic Hquid crystalline state when cyano- or fluorine-substituted biphenyls were used as mesogenic groups attached through a four-methylene spacer (309,310). Other side-chain Hquid crystalline polyoxetanes were observed with a spacer-separated azo moiety (311) and with laterally attached mesogenic groups (312). 

Cesium fluonde in dimethylformamide catalyzes the isomerization offluori-nated cyclobutenes, perfluorobipyntmdines, and their oligomers to products with expanded rings [30, 31, 32] The product distribution in cobalt tnfluonde fluorina-tion depends strongly on the temperature of the reaction [33] Fluorinated 1-dimethylamino-5,6,7,8-tetrafluoro-l,4-dihydro-l,4-ethenonaphthalene rearranges in protic media to a biphenyl derivative [34] (equation 8)... 

Jaffe R, RA Hites (1985) Identification of new, fluorinated biphenyls in the Niagara River Lake Ontario area. Environ Sci Technol 19 736-740. 

An early biphenyl candidate, A-331440 (6) has been reported to be a competitive, potent inverse agonist with balanced activity at human and rat H3Rs with good oral bioavailability [40]. While A-331440 was active in obesity models, its development was precluded by genotoxicity issues [41], The latter was eliminated by a tactical orf/zo-substitution on the phenoxy central core by fluorine to provide A-417022 (7). A-417022 and the 3,5-difluoro analog (A-423579) also produced prolonged weight loss over a 28-day period in a rat diet-induced obesity model [17,41],... 

P. Venkateswarlu, Sodium biphenyl method for determination of covalently bound fluorine in organic compounds and biological methods. Anal. Chem. 54 (1982) 1132-1137. 

F. Leroux, Atropisomerism, biphenyls, and fluorine A comparison of rotational barriers and twist angles, ChemBioChem 5(5) (2004) 644-649. 

Glatt H, Anklam E, Robertson LW. 1992. Biphenyl and fluorinated derivatives liver enzyme-mediated mutagenicity deteced in Salmonella typhimurium and Chinese hamster V79 cells. Mutat Res 281(3) 151-156. 

Simultaneous use of the Fricdcl-Craft catalytic properties of anhydrous hydrogen fluoride and its fluorinating activity in Cl-F replacement reactions has been utilized in the synthesis of numerous trifluoromethyl aromatics (phenyl, biphenyl, and naphthyl derivatives).246 247 The process is based on the action of carbon tetrachloride/hydrogen fluoride (excess) on aromatics, for example, formation of 16,246 17,246 18 and 19.246... 

Lubricant - [MOLYBDENUMAND COMPOUNDS] (Vol 16) -additives [SULFURIZATION AND SULFURCHLORINATION] (Vol 23) -barium as [BARIUM] (Vol 3) -bismuth compounds as [BISMUTH COMPOUNDS] (Vol 4) -boron nitride as [NITRIDES] (Vol 17) -boron tnfluonde as [FLUORINE COMPOUNDS,INORGANIC - BORON - BORON TRIFLUORIDE] (Vol 11) -ceriumcompdm [CERIUM AND CERIUM COMPOUNDS] (Vol 5) -glycerol as [GLYCEROL] (Vol 12) -hydrogenated terphenyls m [BIPHENYL AND TERPHENYLS] (Vol 4) -sodium tetrasulfidemmfg of [SODIUM COMPOUNDS - SODIUM SULFIDES] (Vol 22) -use of lime and limestone [LIME AND LIMESTONE] (Vol 15)... 

The rate of fluorine displacement from fluorotoluenes by H-atoms has been measured in single-pulse shock tubes at 988-114 K.158 The addition of CF3 to CgFsCl has been studied.159 The intermediate adduct radical (CF3C6F5C1) was shown to react with an additional CF3 to give CF3CI and C6F5CF3. A range of fluorinated biphenyls can be produced by the reaction of pentafluorobenzene radicals with both electron-rich and -poor aromatics. The isomeric ratios of biphenyls produced indicated an efficient homolytic chain process.160... 

The benzene derivatives containing the fluorinated sulfone have been prepared either by nucleophilic substitution of the 4-fluorophenyl derivative (e.g. 1) or by starting with the appropriately substituted sodium thiophenoxide and reacting with perfluoroalkyl iodide follow by oxidation with either MCPBA or chromium oxide (12. li.) The biphenyl derivatives have been prepared by palladium catalyzed cross coupling chemistry of the 4-bromophenyl derivative (e.g. 2) with substituted phenyl boronic acid (yields 37-84%) (JLH, .). Compound 16 has been prepared by palladium catalyzed cross coupling of (4-bromophenyl)perfluorohexyl sulfone with vinyl anisole in 37 % yield (JJL). The vinyl sulfones, 7 and 9, have been prepared by condensation of CH3S02Rf (JJL) with the appropriate aldehyde (yields 70,and 73%) following a literature procedure (1 ). Yields were not optimized. 

We have found that use of fluorinated sulfone and SSI acceptors leads to materials with better nonlinearity for their transparency compared with materials containing the conventional acceptors. Figure 3 summarizes our findings, and is a plot of jlp vs Xmax for donor-acceptor CT molecules of benzene, styrene, biphenyl, fluorene, and stil-bene derivatives with fluorinted sulfone, SSI, and other common acceptors (SC>2Me, CN, COH, COMe, and NO2) groups. 

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