Synthesis of a¹⁴C-labeled FPTase inhibitorviaa Pd-catalyzed cyanation with Zn(¹⁴CN)₂andviabromo[¹⁴C]acetic acid

C-14-Labeled farnesyl-protein transferase inhibitor 1a was required for drug metabolism studies. The first approach was to synthesize C-14-labeled 1b using Zn((CN)-C-14)(2) in a Pd-catalyzed cyanation. A second approach was to prepare labeled 1c with the C-14-label in the piperazine ring. All metabolites from 1b were non-radioactive whereas the same metabolites from 1c were all radioactive and quantifiable.