SYNTHESIS OF [BENZYL-7-H-3] AND [BENZOYL-7-C-14] METHYL 4-(2,5-DIHYDROXYBENZYLAMINO)BENZOATE

4-Amino[7-C-14]benzoic acid (3) is prepared by carbonation of the lith ium 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 -C-14]benzoate (5). 5 is reduced with sodium cyanoborohydride to give methyl 4-(2,5-dihydroxybenzylamino)[7-C-14]-benzoate with a specific a ctivity of 38.9 mCi/mmol. Unlabeled 5 is reduced with tritium gas to g ive methyl 4-(2,5-dihydroxy[7-H-3]-benzylamino)benzoate with specific activity of 7.6 Ci/mmol.