Design, synthesis, and SAR of potent and selective dipeptide-derived inhibitors for dipeptidyl peptidases

In this paper we report the systematic search for new, potent, and selective DPP II inhibitors. A study of the structure-activity relationship was conducted starting from aminoacyl pyrrolidides as lead compounds. Rational exploration of the P(1) and P(2) building blocks led to the discovery of some very potent DPP II inhibitors which can be characterized by their high selectivity for DPP II with regard to DPP IV. Dab-Pip and Dab-Pip-2-CN were selected as the most promising inhibitors (IC(50) nM range) and will enable us to study the physiological role of DPP II and to differentiate between DPP II and DPP IV in biological systems.