A series of 2-aminothiadiazole of inhibitors of AKT1 is described. SAR relationships are discussed, along with selectivity for protein kinase A (PKA) and cyclin-dependent kinase 2 (CDK2). Moderate selectivity observed in several compounds for AKT1 versus PKA is rationalized by X-ray crystallographic analysis. Key compounds showed activity in cellular assays measuring phosphorylation of two AKT substrates, PRAS40 and FKHRL1. ...