Hydrofluoric Acid → 3,4,5,2'-Tetrafluoro-4'-(4-fluoro-4-propylcyclohexyl)-biphenyl

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Reaction Conditions

Reaction Steps

8.0 g of 3,4,5,2'-tetrafluoro-4'-(4-propylidenecyclohexyl)biphenyl in 16 ml of dichloromethane were introduced into a Teflon apparatus and cooled to -25° C. 80 ml of a 70% solution of hydrogen fluoride in pyridine were then added dropwise with stirring, and the mixture was stirred for 30 minutes at -25° C. and then for a further 1 hour at room temperature. The reaction solution was poured into a suspension of 10 g of sodium hydrogencarbonate and 200 g of ice-water. The mixture was then extracted with 3×80 ml of hexane. The combined organic extracts were washed once with 50 ml of sodium chloride solution, dried using sodium sulfate, filtered and evaporated to a residue. The crude product was purified by means of a silica-gel frit and the eluate was evaporated to a residue, giving 3,4,5,2'-tetrafluoro-4'-(4-fluoro-4-propylcyclohexyl)-biphenyl (C 73 N (48.8) I, Δε=15.3, Δn=+0.111).

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