Short-RInChIKey=SA-FUHFF-UHFFFADPSC-QVAADPPLQS-UHFFFADPSC-NUHFF-NQLEC-NUHFF-ZZZ

The linear precursor was synthesized according to https://www.chemotion-repository.net/pid/13199. [Dimethylamino(triazolo[4,5-b]pyridin-3-yloxy)methylidene]-dimethylazanium hexafluorophosphate (HATU) (0.75 equiv) was dissolved in 40 mL of DMF. In parallel, N-cyclohexylglycyl-D-prolyl-N-allylglycyl-L-phenylalanine (49.9 mg, 100 μmol, 1.00 equiv.) was dissolved in 20 mL of DMF and DIPEA (103 mg, 139 μL, 800 μmol, 8.00 equiv) was added. 10 mL of this mixture were added to the HATU solution over a period of 6 h at 21 °C. Afterwards, additional 0.75 equiv. of HATU were added to the reaction mixture in one portion. The remaining 10 mL of the linear precursor mixture were added over another period of 6 h. The reaction was stirred for 12 h and the solvent was removed under reduced pressure.