1-Piperazinecarboxylic acid, 4-((2,5-dioxo-4,4-diphenylimidazolidin-1-yl)acetyl)-, ethyl ester 4-((2,5-Dioxo-4,4-diphenylimidazolidin-1-yl)acetyl)-1-piperazinecarboxylic acid ethyl ester 92084-79-2