2-(cyclohexanecarbonyl)-6,7-dihydro-3H-pyrazino[2,1-a]isoquinolin-4-one; Didehydro praziquantel; UNII-SWR6DIS4IU; Praziquantel specified impurity B [EP]; 4H-Pyrazino(2,1-a)isoquinolin-4-one,2-(cyclohexylcarbonyl)-2,3,6,7-tetrahydro; 2-(Cyclohexylcarbonyl)-2,3,6,7-tetrahydro-4H-pyrazino[2,1-a]isoquinolin-4-one; Praziquantel related compound B RS [USP]; Praziquantel related compound B; Praziquantel related compound B [USP]; 2-(Cyclohexylcarbonyl)-2,3,6,7-tetrahydro-4H-pyrazino (2,1-a)isoquinolin-4-one