Discovery of a Novel Series of Imidazo[1,2-a]pyrimidine Derivatives as Potent and Orally Bioavailable Lipoprotein-Associated Phospholipase A2 Inhibitors

Inhibition of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has been suggested to be a promising therapeutic strategy for several inflammation-associated diseases, including atherosclerosis, Alzheimer's disease, and diabetic macular edema. Herein, we report the discovery of a novel series of Lp-PLA(2) inhibitors constructed on an imidazo[1,2-a]pyrimidine scaffold through a conformational restriction strategy. Structure activity relationship (SAR) analysis resulted in the identification of several compounds with high potency in vitro and good metabolic stability in liver S9 fractions. Compounds 7c and 14b selected for further exploration in vivo demonstrated excellent pharmacokinetic profiles and exhibited significant inhibitory efficacy in SD rats upon oral dosing.