150px|thumb|Chemical structure of 2-imidazolidinone 150px|thumb|Chemical structure of 4-imidazolidinone
150px|thumb|Chemical structure of 2-imidazolidinone 150px|thumb|Chemical structure of 4-imidazolidinone
Imidazolidinones are a class of 5-membered ring heterocycles structurally related to imidazolidine. Imidazolidinones feature a saturated C3N2 nucleus, except for the presence of a urea or amide functional group in the 2 or 4 positions.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).