Total solid-phase synthesis of 1,4,7,10-tetraazacyclododecane-N,N ',N '',N'''-tetraacetic acid-functionalized peptides for radioimmunotherapy

A convenient approach to the functionalization of peptides with the macrocy clic 1,4,7,10-tetraazacyclo-dodecane-N,N',N ",N'''-tetraacetic acid (DOTA) moiety has been developed. Protected components (using tert-butyl or tert-b utyloxycarbonyl groups) of both the peptide and the chelate were assembled on the same solid resin support. Deprotection and cleavage of the resin-bou nd DOTA-peptides were performed in one step using a trifluoroacetic acid cl eavage mixture to yield free DOTA-peptide amides.