A hit generation and exploration approach led to the discovery of 31 (2-(4-(6-chloro-2-(4-(dimethylamino) phenyl)-3H-imidazo[4,5-b] pyridin-7-yl) piperazin-1-yl)-N-(thiazol-2-yl) acetamide), a potent, novel inhibitor of Aurora-A, Aurora-B and Aurora-C kinases with IC50 values of 0.042, 0.198 and 0.227 mu M, respectively. Compound 31 inhibits cell proliferation and has good microsomal stability. (c) 2007 Elsevier Ltd. All rights reserved.