Potent and selective ERK5 inhibitor (IC50 = 8 nM). Exhibits >1,000-fold selectivity for ERK5 over a panel of over 200 kinases. Also exhibits selectivity over bromodomain BRD4 (Kd = 3,600 nM). Increases vomocytosis in human macrophages in vitro, as well as in an in vivo zebrafish model of cryptococcal disease, reducing spread of infection. Purity 98%. MW (observed): 648.78