“2 + 1” Dithiocarbamate–isocyanide chelating systems for linking image (M = 99mTc, Re) fragment to biomolecules

“2 + 1” Dithiocarbamate (DTC)–isocyanide (ISO) system was studied to label amino acids and model peptides with View the MathML source99mTc(CO)3+ fragment. Two ways were used: (i) conjugation via free carboxy group of bifunctional DTC [View the MathML sourceS2CNMe2- (L3), S2CNHCH2COO2− (L1) and S2C(C4H7N)COO2− (L2)] using pre-labeling procedure and (ii) conjugation via isocyanide ligand [tert-BuNC (L4), EtOC(O)CH2NHC(O)CH2NC (L5), and gly-gly-gly-CH2NHC(O)CH2NC (L6)]. Complexes M(CO)3L2L4− (1a, 1b), M(CO)3L3L4− (2a, 2b) and bioconjugates M(CO)3L1L5 (5a, 5b), and M(CO)3L1L6 (6b) (a, M = Re; b, 99mTc) were synthesized. Bioconjugates 4a and 4b were prepared by reaction of histidine methyl ester with 2a and 2b, respectively. All rhenium complexes were characterized by 1H and 13C NMR, IR, and MS spectroscopy and complexes with 99mTc, by HPLC using rhenium analogs as references.