| abstract |
A process for preparing 4,4'-bis-benz-ox(-thi,-imid)-azol-2-yl-stilbenes of the formula <IMAGE> wherein R, R1, R2 and R3 may be the same or different from each other and denote hydrogen, C1-C4-alkyl, C1-C4-alkoxy, C1-C4-alkoxycarbonyl, chlorine, bromine, nitro or sulfo and X denotes oxygen, sulfur or NH, which comprises reacting a (4-chloromethyl)-iminobenzoic acid alkyl ester of the formula <IMAGE> wherein R denotes C1-C4-alkyl or C1-C4-alkoxyethyl, or HCl salts thereof, with o-aminophenol, o-aminothiophenol or o-phenylene diamine and reacting the resulting 2-benz-ox(-thi,-imid)-azolyl-4-chloromethyl-benzenes with potassium hydroxide or sodium hydroxide in a polar aprotic solvent. |