Synthesis of 14C-labeled S-(-)-1-phenylethylamine and its application to the synthesis of [14C] CI-1021, a potential antiemetic agent(1)

Article abstract of DOI:10.1002/1099-1344(20001015)43:11<1087::AID-JLCR394>3.0.CO;2-7

S-(-)-1-[U-ring- ¹⁴C]phenylethylamine 3 was synthesized through the enantioselective borane reduction of E-[U-ring-¹⁴C]acetophenone oxime methyl ether derived from [U-ring-¹⁴C]acetophenone. The overall radiochemical yield was 66.7%. The enantiomeric excess (ee) was 96.60%. Coupling the labeled amine 3 with (R)-N-[(benzo[b]furan-2-ylmethoxy)-carbonyl-2-methyltryptophan 4 provided [R-(R* , S*)] {1-(1H-indole-3-ylmethyl)-1-methyl-2-oxo-2-[(1-[U-ring-¹⁴C]phenylethyl) amino]ethyl} carbamic acid benzo[b]furan-2-ylmethyl ester (CI-1021), a potential antiemetic agent.