obtained in 50 yield based on 1 2 dichlorohexafluorocyclopentene used by vacuum distillation the 19 f nmr neat u03c6 108 3 2f 110 5 2f and 126 1 2f are to f 3 on the ring and 117 2 2f 121 3 2f 126 1 2f 134 5 2f are to the one alkyl chain ms m m z 440 442 m f m z 421 423 str21 m z 209 211 were observed in relative intensities of 48 9 16 6 18 0 5 7 85 9 28 1 and 100 33 8 respectively hexafluorobenzene 13 9 g 0 11 mol and 2 3 butanediol 67 7 g 0 72 mol were refluxed in the presence of 1 15 mol of naoh after work up of the 3 hydroxy 2 butoxypentafluoro benzene 19 g boiling at 64 u00b0 70 u00b0 c 0 35 mmhg 73 yield based on hexafluorobenzene was obtained by vacuum distillation 3 hydroxy 2 butoxypentafluorobenzene thus obtained was refluxed with dimethyl formamide dmf in the presence of k 2 co 3 after work up of the reaction mixture str22 was obtained as crystal in 58 yield example 6 str23 7 g obtained in the example 5 was dissolved in f113 to make a 4 w v solution f113 was used as the reaction medium.