Synthesis of triple (13C2, 15N), single (14C), and double (14C2) labeled trimetrexate

Abstract A method was developed for the synthesis of triple ( 13 C 2 , 14 N) labeled trimetrexate. A method for single carbon‐14 labeled synthesis is also described. Modifications of the triple labeled synthesis with carbon‐14 produced a doubled carbon‐14 labeled trimetrexate.