Synthesis of C-functionalized trans-cyclohexyldiethylenetriaminepenta-acetic acids for labelling of monoclonal antibodies with the bismuth-212 α-particle emitter

Several C-functionalized cyclohexyldiethylenetriaminepenta-acetic acid derivatives have been prepared from (±)-4-nitrophenylalanine and (±)-trans-cyclohexane-1,2-diamine to produce two sets of diastereoisomeric enantiomers. A modification of this synthesis has been employed to prepare a single enantiomer in order to define the absolute configurations of the products.