2-Azidoethoxy derivatives of 2-aminocyclohexanecarboxylic acids (ACHC): interesting building blocks for the synthesis of cyclic -peptide conjugates

Oligomers of cyclic beta-aminoacids possess a high resistance to peptidase-catalyzed hydrolysis and display a high intrinsic tendency to adopt regular secondary structures. These characteristics are attractive to develop new biologically active substances. However, cyclic-betapeptides often show limited solubility in water and cannot be conjugated to biologically relevant fragments, such as oligosaccharides, which are often essential for full biololgical activity of natural alfapeptides. In this article, we report the synthesis of one trans- and one cis-2-aminocyclohexane carboxylic acid (ACHC) both functionalized with a hydroxy group, to increase the solubility in water, and an azidoethoxy group to allow the synthesis of cyclic-beta-peptide conjugates by a "click reaction"