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4‐Amino[7‐14C]benzoic acid (3) is prepared by carbonation of the lithium salt of N, N‐bis(trimethylsilyl)aniline. The methyl ester (4) of 3 is generated with trimethylsilyldiazomethane, and 4 is coupled with 2,5‐dihydroxybenzaldehyde to yield methyl 4‐(2,5‐dihydroxybenzylimino)[7‐14C]benzoate (5). 5 is reduced with sodium cyanoborohydride to give methyl 4‐(2,5‐dihydroxybenzylamino)[7‐14C]‐benzoate with a specific activity of 38.9 mCi/mmol. Unlabeled 5 is reduced with tritium gas to give methyl 4‐(2,5‐dihydroxy[7‐3H]‐benzylamino)benzoate with specific activity of 7.6 Ci/mmol.