SUMMARYThe potential of a clean, rapid exchange between the nitrile function of mandelonitrile and cyanide was examined for the preparation of labeled mandelonitrile which could be subsequently rapidly reduced with borane to labeled phenylethanolamine (PEOH) . The mandelonitrile exchange (CN-CN) was studied using crown ethers in THF, monitoring the results with lJC-NMR. A large increase in the intensity of the signal due to [l3C]-nitri1e was observed. The exchange was also carried out using [ 14C]-NaCN, and the exchanged nitrile was reduced to r14C]-PE0H. yield for the reduction of [14C]-mandelonitrile to [14C]-PEOH was 60% and the overall radiochemical yield of the cyanide-exchange and borane reduction (based on [14C]-NaCN used) was 20%. nisms are proposed which were found to be consistent with results of cyanide exchange of appropriately selected nitriles.
13CI-NaCN withThe chemical Mecha-