Antidiarrhetic loperamide hydrochloride.

Single crystals of the anhydrous form of the title compound {systematic name: 1-[3-(dimethylcarbamoyl)-3,3-diphenylpropyl]-4-hydroxy-4-(4-chlorophenyl)piperidin-1-ium chloride}, C(29)H(34)ClN(2)O(2)(+)·Cl(-), were obtained by diffusion of acetone into a solution in 2-propanol. In the structure, N-H...Cl(-) and O-H...Cl(-) hydrogen bonds connect neighbouring molecules and chloride anions to form chains along the c-axis direction. Neighbouring chains along the b-axis direction are connected by intermolecular C-H...Cl(-) contacts, defining layers parallel to the (100) planes. The layers are connected by weak intermolecular C-H...Cl interactions only, which may account for the plate-like shape of the crystals.