A selective inhibitor of the TGF-β type1 receptor ALK5 (IC50s = 4, 18, and 23 nM for ALK5 autophosphorylation, TGF-β cellular assay, and ALK5 binding in HepG2 cells, respectively); used to induce stem cell pluripotency by replacing the reprogramming transcription factor Sox2 via inhibition of the TGF-β signaling pathway and induction of Nanog transcription