合成路线1

Palladium-catalyzed coupling of methyl 5-iodosalycilate (I) with trimethylsilyl acetylene (II) produced the ethynyl salycilate (III). The trimethylsilyl protecting group of (III) was then cleaved by treatment with KF in DMF to give (IV). On the other hand, sulfonamide (VII) was obtained by condensation of 4-iodobenzenesulfonyl chloride (V) with 2-amino-3-methylpyridine (VI). A further Suzuki coupling between acetylene (IV) and iodosulfonamide (VII) furnished diaryl acetylene (VIII). The methyl ester group of (VIII) was finally saponified with NaOH to provide the target carboxylic acid.