Orteronel is a 7S-stereoisomer of a 6,7-dihydro-5H-pyrrolo[1,2-c]imidazole substituted with hydroxy and 6-(methylcarbamoyl)naphthalen-2-yl groups. It is a non-steroidal 17,20-lyase inhibitor that inhibits androgen synthesis. Previously in clinical development for castration-resistant prostate cancer (now discontinued), it functions as an antineoplastic agent, a sterol biosynthesis inhibitor, and an EC 1.14.99.9 (steroid 17α-monooxygenase) inhibitor. It is classified as a naphthalenecarboxamide, a secondary carboxamide, a pyrroloimidazole, and a tertiary alcohol.
