Peptides by extension at the N- or C-terminii of lysine

Abstract

Dipeptides 3a-g, (3a + 3a′), (3d + 3d′), (3l + 3l′) a and tripeptides 6a-e, (6b + 6b′), (6e + 6e′) incorporating Zε-Lys were prepared in high yields (70-95%) and enantiopurity (≥97%) in partially aqueous acetonitrile solution by coupling using (i) Zε-Lys with N-(Z- and Fmoc-aminoacyl)benzotriazoles 1a-g, (ii) Zε-Lys with N-Z-dipeptidoylbenzotriazoles 5a-c, and (iii) N-Fmocα-Zε-l-Lys-Bt 1h and amino acids 2a,c-e. Unnatural dipeptides 3h-j, (3h + 3h′) and tripeptides 6f were similarly prepared from Zα-Lys. Retention of chirality was demonstrated by parallel experiments involving l-Ala, dl-Ala, l-Met, and dl-Met by NMR and HPLC analysis. © 2006 The Authors.