2,6-Piperazinedione, 4,4'-(1,2-cyclopropanediyl)bis-, cis- 4,4'-(1,2-Cyclopropanediyl)bis(2,6-piperazinedione) 66054-21-5 cis-4,4'-(1,2-Cyclopropanediyl)bis(2,6-piperazinedione)