Development of CXCR3 antagonists. Part 2: Identification of 2-amino(4-piperidinyl)azoles as potent CXCR3 antagonists.

Development of a lead series of piperidinylurea CXCR3 antagonists has led to the identification of molecules with alternative linkages which retain good potency. A novel 5-(piperidin-4-yl)amino-1,2,4-thiadiazole derivative was found to have satisfactory in vitro metabolic stability and to be orally bioavailable in mice, giving high plasma concentrations and a half life of 5.4h.