1: 4-bromophenylacetic acid With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Metallation; 2 h; 2: n-butyllithium; [carboxyl-14C]-benzoic acid methyl ester in tetrahydrofuran; hexane T=-75°C; Condensation; 2 h;

lithium aluminium tetrahydride in diethyl ether Reduction;