The dipicolylamino group as an efficient leaving group for amide bond formation via hexafluoroisopropyl ester.

Peptide dipicolylamide was prepared by the solid-phase method. The amide was activated by Cu(II) ions in hexafluoroisopropanol and converted to the corresponding active ester. It was condensed with the C-terminal segment to realize segment coupling. The method was successfully applied to the synthesis of an atrial natriuretic peptide and RNase T1.