How is 4-[3,5-bis(4-carboxyphenyl)phenyl]benzoic acid (CAS: 50446-44-1) typically synthesized?

4-[3,5-bis(4-carboxyphenyl)phenyl]benzoic acid is typically synthesized through a multistep process involving the coupling of 4-carboxybenzoic acid with 3,5-dibromobenzophenone. The synthesis involves the formation of an aryl coupling intermediate followed by the introduction of carboxylic acid groups. The reaction is carried out under mild conditions using catalytic amounts of palladium(II) acetate and triphenylphosphine as a ligand. The overall yield is around 70-80%.