Peptide beta-turn mimetic compounds and processes for making them

The subject invention involves compounds having structure (I), wherein: (a) R1 is hydrogen or alkyl; and R2 is selected from hydrogen, alkyl, aryl, heterocyclyl, carboxy and its esters and amides; or R1 and R2 are attached and are together alkylene or heteroalkylene; (b) R4 is selected from aryl, heteroaryl, and alpha,beta-unsaturated conjugated aryl or heteroaryl; and (c) R5 is selected from hydrogen, alkyl, aryl, and heterocyclyl; and an optical isomer, diesteriomer, or enantiomer thereof; a salt, hydrate, ester, amide or imide thereof. The subject invention also includes libraries of such compounds, and processes for making the subject compounds and libraries.