The molecular formula C21H28O3 may refer to: Estradiol monopropionate Estradiol 3-propionate HU-331 HU-336 6-Ketoprogesterone 11-Ketoprogesterone Nomegestrol Pyrethrin I SC-8109 Segesterone
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).