Effects of the incorporation of IBTM β-turn mimetics into the dipeptoid CCK1 receptor agonist PD 170292

Abstract Replacement of the 2-Adoc- d -αMeTrp residue in the non-selective CCK 1 receptor agonist PD 170292 by the Z-(2 R ,5 R ,11b S )-IBTM skeleton, able to fix a type II β-turn-like conformation, led to a conformationally restricted dipeptoid analogue, namely 3a , which exhibited a notable increase in the CCK 1 selectivity and antagonist properties.