Scheme 1. Synthetic routes to peptidomimetics. Reagents and conditions. (a) Fmoc-Ser(t-Bu)-OH, HBTU, DIPEA, DMF; (b) 20% piperidine–DMF; (c) R3COOH, HATU, DIPEA, DMF; (d) 0.5% TFA in DCM; (e) R4NH2, HATU, DIPEA, DMF; (f) TFA–TIPS–H2O (95 : 2.5 : 2.5); (g) Fmoc-Lys(Boc)-OH, HBTU, DIPEA, DMF; (h) Cu(OAc)2, pyridine, DCM, R4NH2.
