4-ethyl-N-(4-hydroxyphenyl)-2,3-dioxo-1-piperazinecarboxamide, Benzeneacetic acid,a-[[(4-ethyl-2,3-dioxo-1-piperazinyl)carbonyl]amino]-4-hydroxy, {[(4-ETHYL-2,3-DIOXO-1-PIPERAZINYL) CARBONYL]AMINO}-4-HYDROXY-BENZENE ACETIC ACID, 4-ethyl-N-(4-hydroxyphenyl)-2,3-bis(oxidanylidene)piperazine-1-carboxamide,