1,2-Bis(4-methoxycarbonyloxymethyl-3,5-dioxopiperazin-1-yl)ethane 1,2-Ethanediylbis((2,6-dioxo-4,1-piperazinediyl)methylene)dimethyl carbonate 98632-24-7 Carbonic acid, 1,2-ethanediylbis((2,6-dioxo-4,1-piperazinediyl)methylene)dimethyl ester ZSB 21