Polymerizable compounds and the use thereof in liquid-crystal displays

A process for preparing a compound of formula

• by esterification of a compound of the formula
• wherein
• L is on each occurrence identically or differently F, CI, —CN, P—Sp—, or straight chain alkyl having 1 to 25 C atoms, or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or CI, or L has the meaning of La,
• Sp is a spacer group that is optionally substituted by one or more groups P, or a single bond,
• P is a polymerizable group,
• r1, r3, r7 are independently of each other 0, 1, 2 or 3,
• r2 is 0, 1, 2, 3 or 4,
• r4, r5, r6 are independently of each other 0, 1 or 2,
• with r1+r7≥1, r1+r2+r3 1, r4+r5 1, r1+r3+r4 1, R denotes H, and Pg denotes OH,
• and wherein one R is H and one R is Sp-Pg, or one Sp group is substituted by one or more Pg groups such that Sp-Pg corresponds to Sp(Pg), with s being ≥2, using corresponding acids, acid derivatives, or halogenated compounds containing a group P, in the presence of a dehydrating reagent.

A liquid crystalline medium comprising one or more polymerizable compounds of formula I1-4

• wherein
• L is on each occurrence identically or differently F, Cl, —CN, P—Sp—, or straight chain alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl, or L has the meaning of La,
• La is a straight-chain alkoxy group with 1 to 12 C atoms or a branched alkoxy group with 3 to 12 atoms, and is optionally fluorinated,
• r1 and r7 are independently of each other 0, 1, 2 or 3, with r1+r7≥1,
• wherein the compounds contain at least one substituent L that denotes La,
• P denotes acrylate or methacrylate, and all groups P that are present have the same meaning,
• Sp, is —(CH2)p2—, —(CH2)p2—O—, —(CH2)—CO—O—, or —(CH2)—O—CO—, wherein p2 is 2, 3, 4, 5 or 6, and the O-atom or the CO-group, respectively, is connected to the aromatic ring,
• one or more compounds of the formulae CY and/or PY:
• in which the individual radicals have the following meanings:
• a denotes 1 or 2,
• b denotes 0 or 1,
• denotes
• R1 and R2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH2 groups may be replaced by —O—, —CH═CH—, —CO—, —O—CO— or
• —CO—O— in such a way that O atoms are not linked directly to one another,
• ZX denotes —CH═CH—, —CH2O—, —OCH2—, —CF2O—, —OCF2—, —O—, —CH2—, —CH2CH2— or a single bond,
• L1-4 each, independently of one another, denote F, Cl, OCF3, CF3, CH3, CH2F, CHF2 and
• one or more compounds of formulae AN1 or ZK1:
• in which alkyl denotes a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-7 C atoms,
• in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms.