Mirodenafil is a pyrrolopyrimidine compound with the structure of 3,5-dihydro-4H-pyrrolo[3,2-d]pyrimidin-4-one. It features a 5-{[4-(2-hydroxyethyl)piperazin-1-yl]sulfonyl}-2-propoxyphenyl group at position 2, an ethyl group at position 5, and a propyl group at position 7. It is a phosphodiesterase type 5 inhibitor used for treating erectile dysfunction. It functions as an EC 3.1.4.35 (3',5'-cyclic-GMP phosphodiesterase) inhibitor and a vasodilator. It is classified as a sulfonamide, a pyrrolopyrimidine, a N-alkylpiperazine, a primary alcohol, and an aromatic ether.