Synthesis of new AB-type monomers for polybenzimidazoles from N-(4,5-dichloro-2-nitrophenyl)acetamide

S_NAr reaction between N-(4,5-dichloro-2-nitrophenyl)acetamide and 4-hydroxybenzoic acid gives 4-(5-acetylamino-2-chloro-4-nitro- phenoxy)benzoic acid and 4-{5-[(5-acetylamino-2-chloro-4-nitrophenyl)amino]-2-chloro-4-nitrophenoxy}benzoic acid which were used for the synthesis of new AB-type monomers for polybenzimidazoles.