PURPOSE: To provide new chemically stable tolane derivatives capable of, by mixing with another liquid crystalline composition, increasing the anisotropy value of refractive index of the above-mentioned composition.
CONSTITUTION: Compounds of formula I (A is trans-1,4-disubstituted cyclohexylene ring or 1,4-disubstituted phenylene ring in which one or two or more CH or one or two or more CH2 respectively may be replaced with N or with O or S; R is H or 1-10C alkyl, provided that 0 or C=C may be inserted into C-C bond in group or C-C bond between group and ring in case of alkyl group; Z is COO, O, OCO, CH2CH2, CH2, CH2O, OCH2 or single bond; Ph is 1,4disubstituted duphenylene ring; n is 0 or 1). The above-mentioned compounds can be obtained by reacting a 4-substituted-4'-fluorotolane of formula 9 derived from a compound of formula 2 with a sodium 2,2,2-trifluoroethoxide of formula 10.
INOUE KANJI
