Paliperidone: 3-{2-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]eth­yl}-9-hy­droxy-2-methyl-1,6,7,8,9,9a-hexa­hydro­pyrido[1,2-a]pyrimidin-4-one

The title compound (also known as 9-hy­droxy­risperidone), C(23)H(27)FN(4)O(3), is a heterocyclic compound with manifold pharmacological properties. The hy­droxy group shows disorder over two positions, with site-occupancy factors of 0.856 (2) and 0.144 (2). The piperidine ring adopts a chair conformation, while the annulated ring bearing the hy­droxy group is present in a half-chair conformation. Classical O—H⋯O hydrogen bonds as well as C—H⋯N contacts connect the mol­ecules into undulating sheets lying perpendicular to the crystallographic b axis. The shortest centroid–centroid distance between two centers of gravity is 3.5867 (8) Å and is apparent between the benzoxazole moiety and the six-membered ring bearing the keto substituent.