137424-80-7 2-Piperazinecarboxylic acid, 4-(3-phosphono-2-propenyl)- 3-(2-Carboxypiperazine-4-yl)-1-propenyl-1-phosphonic acid 4-(3-Phosphonoprop-2-enyl)piperazine-2-carboxylic acid Cppene D-Cpp-ene Sdz eaa 494