NCT-505 is a potent and selective aldehyde dehydrogenase (ALDH1A1) inhibitor, with an IC50 of 7 nM, and weakly inhibits hALDH1A2, hALDH1A3, hALDH2, hALDH3A1 (IC50s, >57, 22.8, 20.1, >57 μM). NCT-505 (Compound 86) is a potent and selective aldehyde dehydrogenase (ALDH1A1) inhibitor, with an IC50 of 7 nM, and weakly inhibits hALDH1A2, hALDH1A3, hALDH2, hALDH3A1 (IC50s, >57, 22.8, 20.1, >57 μM). NCT-505 has no obvious inhibitory effec on 5-hydroxyprostaglandin dehydrogenase (HPGD) and type-4 hydroxysteroid dehydrogenase (HSD17β4) (IC50, >57 μM). Moreover, NCT-505 shows potent cellular activities, reducing the viability of OV-90 cells with an EC50 of 2.10-3.92 μM. NCT-505 is also cytotoxic to SKOV-3-TR cells, with IC50s of 1, 3, 10, 20, 30 μM, respectively, in the titration assay.