Discovery and optimization of new oxadiazole substituted thiazole RORγt inverse agonists through a bioisosteric amide replacement approach

Starting from previously identified thiazole-2-carboxamides exemplified by compound 1/6, two new series of ROR gamma t inverse agonists with significantly improved aqueous solubility, ADME parameters and oral PK properties were discovered. These scaffolds were identified from a bioisosteric amide replacement approach. Amongst the variety of heterocycles explored, a 1,3,4-oxadiazole led to compounds with the best overall profile for SAR development and in vivo exploration. In an ex vivo mouse PD model, concentration dependent efficacy was demonstrated and compounds 3/5 and 6/3 were profiled in a 5-day rat tolerability study.