Selective activator of Epac, the cAMP-sensitive guanine nucleotide-exchange factor for Rap1 and Rap2. Activates Epac1 (EC50 = 2.2 μM), but not PKA (EC50 > 10 μM). Stimulates Epac-mediated Ca2+-mediated Ca2+ release in pancreatic β-cells in vitro.