We synthesized 4-aminopiperidine derivatives of our prototype integrin αvβ3 antagonist 1 in an attempt to increase the activity and water solubility. Introduction of one or two hydrophilic moieties into the central aromatic ring and/or the benzene ring at the C-terminus of 1 increased water solubility and enhanced inhibition of cell adhesion. The results of a structure–activity relationships (SAR) study indicated that the torsion angle between the ...