(S)-(+)-cis-4'-Benzyl-oxypraziquantel

The asymmetric unit of the title compound, C26H30N2O3 {systematic name (S)-(+)-2-[cis-4-(benz-yloxy)cyclo-hexa-ne-carb-on-yl]-1,2,3,6,7,11b-hexa-hydro-4H-pyrazino-[2,1-a]isoquin-olin-4-one}, consists of two independent mol-ecules in which the O= Camide group is syn to the N-C(C=Olactam) moiety, making dihedral angles of 2.0 (8) and 3.7 (8)°. The conformation of the 1,4-disubstituted cyclo-hexane ring is cis in each independent mol-ecule, with the carbonyl group occupying an equatorial position and the benz-yloxy group an axial position. In one mol-ecule, two C and one O atom of the benz-yloxy group are disordered over two sets of sites, with a refined occupancy ratio of 0.772 (8):0.228 (8). In the crystal, mol-ecules are linked by C-H⋯O inter-actions, forming ribbons parallel to the b-axis direction.