2,3-difluorohydroquinone derivatives

摘要

PCT No. PCT/EP89/00179 Sec. 371 Date May 15, 1989 Sec. 102(e) Date May 15, 1989 PCT Filed Feb. 27, 1989 PCT Pub. No. WO89/08637 PCT Pub. Date Sep. 21, 1989.2,3-difluorohydroquinone compounds of the formula I <IMAGE> I in which R1 and R2, in each case independently of one another, are alkyl having 1 to 15 C atoms or alkenyl having 3 to 15 C atoms which are unsubstituted, monosubstituted by cyano or at least monosubstituted by fluorine or chlorine, it also being possible for one CH2 group in these radicals to be replaced by -O-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, A1, A2 and A3, in each case independently of one another, are (a) trans-1,4-cyclohexylene, in which, in addition, one or two non-adjacent CH2 groups may be replaced by -O- and/or -S-, (b) 1,4-phenylene, in which, in addition, one or two CH groups may be replaced by N, or (c) a radical from the group comprising piperidine-1,4-diyl, 1,4-bicylo (2,2,2)-octylene (sic), 1,3,4-thiadiazole-2,5-diyl, napththalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, it being possible for the radicals (a) and (b) to be monosubstituted or polysubstituted by F, Cl, CH3 or CN, Z1 is -CO-O-, -O-CO-, -CH2CH2-, -OCH2-, -CH2O-, -C 3BOND C- or a single bond, Q1 and Q2, in each case independently of one another, are -CO- or -CH2-, m and n are each 0, 1 or 2, and (m+n) is 0, 1 or 2, are suitable as components of liquid-crystalline phases.