A new class of Aurora-A inhibitors have been identified based on the 2-amino-pyrrolo[2,3-d]pyrimidine scaffold. Here, we describe the synthesis and SAR of this novel series. We report compounds which exhibit nanomolar activity in the Aurora-A biochemical assay and are able to inhibit tumor cell proliferation. This study culminates in compound 30, an inhibitor with potent activity against Aurora A (IC50 = 0-008 mu M), anti-proliferative activity against several tumor cell lines and induces polyploidy in H460 cells. (c) 2006 Elsevier Ltd. All rights reserved.