Clickable bifunctional radiometal chelates for peptide labeling

Abstract

Novel synthetic methods for producing an array of chelates for use in "click"-radiolabeling of peptides are described, and their reactivity with regards to subsequent conjugation and radiolabeling is discussed.

Fig. 1

DFT optimized structure of the hypothetical model complex. r(Cu⋯N3) = 2.559 Å; r(Cu–N4) = 2.110 Å; r(Cu–N5) = 2.092 Å; r(Cu–N7) = 2.299 Å; r(Cu–O1) = 1.930 Å.

Scheme 1

Synthesis of the “clickable” chelates. (i) See ESI for full details.

Scheme 2

“Click” conjugation onto the model peptide. (i) CuCl₂, ascorbic acid in water, RT; (ii) trifluoroacetic acid, iPr₃SiH, EDT.