(S)-(+)-cis-4′-Benzyl­oxypraziquantel

The asymmetric unit of the title compound, C₂₆H₃₀N₂O₃ {systematic name (S)-(+)-2-[cis-4-(benz­yloxy)cyclo­hexa­ne­carb­on­yl]-1,2,3,6,7,11b-hexa­hydro-4H-pyrazino­[2,1-a]isoquin­olin-4-one}, consists of two independent mol­ecules in which the O= C_amide group is syn to the N—C(C=O_lactam) moiety, making dihedral angles of 2.0 (8) and 3.7 (8)°. The conformation of the 1,4-disubstituted cyclo­hexane ring is cis in each independent mol­ecule, with the carbonyl group occupying an equatorial position and the benz­yloxy group an axial position. In one mol­ecule, two C and one O atom of the benz­yloxy group are disordered over two sets of sites, with a refined occupancy ratio of 0.772 (8):0.228 (8). In the crystal, mol­ecules are linked by C—H...O inter­actions, forming ribbons parallel to the b-axis direction.