Discovery of Potent 3,5-Diphenyl-1,2,4-oxadiazole Sphingosine-1-phosphate-1 (S1P₁) Receptor Agonists with Exceptional Selectivity against S1P₂and S1P₃

A class of 3,5-diphenyl-1,2,4-oxadiazole based compounds have been identified as potent sphingosine-1-phosphate-1 (S1P(1)) receptor agonists with minimal affinity for the S1P(2) and S1P3 receptor subtypes. Analogue 26 (S1P(1) IC50 = 0.6 nM) has an excellent pharmacokinetics profile in the rat and dog and is efficacious in a rat skin transplant model, indicating that S1P(3) receptor agonism is not a component of inummosuppressive efficacy.