| 摘要 |
NEW MATERIAL:Dichroic polyazo dyes of formula I, wherein Z1, Z2 are each Y1, cycloalkyl, alkoxyalkoxy, cyano, etc.; Y1, Y2 are each H, alkyl, aryl, halogen; Ar is a group of formula II or III (wherein Y3, Y3 are each Y1); X is H alkyl; Y5, Y6 are each X, OH, cyano, a group of formula IV or V (wherein R is H, lower alkyl); n is 1-2. EXAMPLE:Compd. of formula VI USE:Dichroic polyazo dyes for liquid crystal display, which have a high dichroic ratio and excellent durability and develop purple to bluish purple. PREPARATION:A 2-(4'-aminobiphenyl) benzoxazole of formula VII is diazotized and then coupled with a compd. of formula VIII. The resulting monoazo dye is diazotized and then coupled with a compd. of formula IX. The resulting disazo compd. is diazotized and then coupled with a compd. of formula X.
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