Improved Preparation on Decagram Scale of 5, 8-Dihydro-4, 6-dihydroxy-5, 8-dioxoquinoline-2-carboxylic Acid, a Key Intermediate of Pirenoxine. (2nd November 2022) - Reddy, T. Purendar; Karumanchi, Kishore; Chavakula, Ramadas; Padma, M.