Friedel-Crafts condensation of 4-bromophenol (I) with 1-adamantanol (II) in the presence of H2SO4 yielded the adamantyl phenol (III). Subsequent alkylation of the sodium phenoxide of (III) with iodomethane produced the methyl ether (IV). The Grignard reagent (V), prepared from aryl bromide (IV), was converted to the organozincate derivative, and then subjected to a nickel-catalyzed cross-coupling with methyl 6-bromo-2-naphthoate (VI) to furnish adduct (VII). The target carboxylic acid was finally obtained by saponification of the methyl ester (VII).

The bromination of 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid methyl ester (I) with Br2 in dichloromethane gives the dibromo derivative (II), which is hydrogenated with tritium gas over Pd/C in THF containing TEA to yield the bis tritiated ester (III). Finally, ester (III) is hydrolyzed with NaOH in refluxing methanol to afford the target tritiated naphthoic acid.

Friedel-Crafts condensation of 4-bromophenol (I) with 1-adamantanol (II) in the presence of H2SO4 yielded the adamantyl phenol (III). Subsequent alkylation of the sodium phenoxide of (III) with iodomethane produced the methyl ether (IV). The Grignard reagent (V), prepared from aryl bromide (IV), was converted to the organozincate derivative, and then subjected to a nickel-catalyzed cross-coupling with methyl 6-bromo-2-naphthoate (VI) to furnish adduct (VII). The target carboxylic acid was finally obtained by saponification of the methyl ester (VII).