Aromatic disazo dyes and liquid-crystalline materials containing these dyes

Claim 1

An azo dye of the formula: ##STR37## wherein: X is a 5-membered heterocyclic ring selected from the group consisting of oxadiazole, thiadiazole, thiazole, an oxadiazole ring substituted by C 1 -C 12 alkyl, C 2 - or C 3 -alkyl substituted by hydroxy, C 1 -C 12 alkoxy, phenyl or phenoxy, phenylmethyl, C 5 -C 7 -cycloalkyl, phenyl, or phenyl substituted by C 1 -C 12 -alkyl, phenylmethyl, phenylethyl, C 1 -C 12 -alkoxy, phenoxy, phenylmethoxy, C 1 -C 12 -alkanoyloxy, benzoyloxy, phenyl, diphenyl, cyclohexyl, 4-(C 1 -C 7 -alkylcyclohexyl), carboxylic ester or chlorine, C 1 -C 12 -alkylthio, C 5 -C 7 -cycloalkylthio, phenylmethylthio substituted by C 1 -C 12 -alkyl, phenylmethyl, phenylethyl, C 1 -C 12 -alkoxy, phenoxy, phenylmethoxy, C 1 -C 12 alkanoyloxy, benzoyloxy, phenyl, diphenyl, cyclohexyl, 4-(C 1 -C 7 -alkylcyclohexyl), carboxylic ester or chlorine, or 2-phenylethylthio, a thiadiazole ring substituted by C 1 -C 12 -alkyl, C 2 - or C 3 -alkyl substituted by hydroxyl, C 1 -C 12 -alkoxy, phenyl or phenoxy, phenylmethyl, C 5 -C 7 -cycloalkyl, phenyl, or phenyl substituted by C 1 -C 12 -alkyl, phenylmethyl, phenylethyl, C 1 -C 12 -alkoxy, phenoxy, phenylmethoxy, C 1 -C 12 alkanoyloxy, benzoyloxy, phenyl, diphenyl, cyclohexyl, 4-(C 1 -C 7 -alkylcyclohexyl), carboxylic ester or chlorine, C 1 -C 12 -alkylthio, C 5 -C 7 -cycloalkylthio, phenylmethylthio substituted by C 1 -C 12 -alkyl, phenylmethyl, phenylethyl, C 1 -C 12 -alkoxy, phenoxy, phenylmethoxy, C 1 -C 12 -alkanoyloxy, benzoyloxy, phenyl, diphenyl, cyclohexyl, 4-(C 1 -C 7 -alkylcyclohexyl), carboxylic ester or chlorine, or 2-phenylethylthio or a thiazole ring substituted by C 1 -C 4 -alkyl, phenyl, phenyl substituted by C 1 -C 4 -alkyl, chlorine or bromine, C 5 -C 7 -cycloalkyl or C 1 -C 8 -alkoxycarbonyl; Y is a radical of the formula: ##STR38## the rings, A, B and C are each independently unsubstituted, or ring A is substituted by chlorine, bromine, cyano, methyl, ethyl, methoxy, ethoxy or hydroxyl, or ring B is substituted by chlorine, bromine, methyl, ethyl, methoxy, ethoxy, acetylamino, propionylamino or ring B is a naphthyl ring, or ring C is substituted by chlorine, bromine, methyl, ethyl, methoxy, ethoxy, acetylamino, propionylamino or ring C is a naphthyl ring; R 1 and R 2 are each independently hydrogen, C 1 -C 12 alkyl, cyclohexyl, 2-phenylethyl, 2-cyanoethyl, 2-hydroxyethyl, 2-acetoxyethyl, 2-butyryloxyethyl, allyl, phenylmethyl, 4-butylphenylmethyl, 4-cyclohexylphenylmethyl or 4-(4'-butylcyclohexyl)-phenylmethyl; or R 1 and R 2 , together with a nitrogen atom to which they are both bound, are piperidino, pyrrolidino or morpholino; R 3 is C 1 -C 12 alkyl, C 1 -C 12 alkyl interrupted by oxygen, C 5 -C 7 cycloalkyl, phenylmethyl, 2-phenylethyl, 4-(C 1 -C 12 -alkyl)-phenylmethyl, 4-cyclohexylphenylmethyl, 4-(4'-C 1 -C 7 -alkyl-cyclohexyl)-phenylmethyl, 4'-(C 1 -C 12 -alkoxy)-phenylmethyl, 4-phenoxyphenylmethyl, 4-phenylmethyloxyphenylmethyl, 4-(C 1 -C 12 -alkanoyloxy)-phenylmethyl, benzoyloxyphenylmethyl or 4-caproyloxyphenylmethyl; and R 4 is hydrogen, C 1 -C 4 alkyl or cyclohexyl.