A cell-permeable piperazinyl-pyrimidine compound that acts as an inhibitor against S6K1 (Ki=20nM; IC50=160nM) and MSK1 (IC50=950nM) kinase activity, exhibiting little or much reduced potency against 85 other protein and lipid kinases ( IC50=4.7, 9.2, 65uM, respectively, against RSK1, RSK2, and S6K2; <27% inhibition of the rest at 1uM). Shown to selectively inhibit IGF1- and PMA-stimulated S6K1 substrates phosphorylation in HEK-293 cells in a dose-dependent manner (up to 10uM) in vitro and alleviate heart remodeling and functional damage in a MI (myocardial infarction) model in mice in vivo (75/mg/kg/daily i.p.).