J. P. Jasinski, C. J. Guild, A. S. Dayananda, H. S. Yathirajan and A. R. Ramesha.
Redetermination of loperamide monohydrate, Acta Cryst. (2012). E68, o539-o540 The structure of the title compound {systematic name: 4-[4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl]-N,N-dimethyl-2,2-diphenylbutanamide monohydrate}, C29H33ClN2O2·H2O, has been redetermined at 170 (2) K. The redetermination is of significantly higher precision than the previous structure determination at room temperature and includes the H-atom coordinates that were not included in the previous report [Germain et al. (1977). Acta Cryst. B33, 942-944]. It consists of a piperidin-1-yl ring in a distorted chair conformation, with the N,N-dimethyl-[alpha],[alpha]-diphenylbutyramide and the 4-chlorophenyl and hydroxy groups bonded in para positions and an external water molecule within the asymmetric unit. The dihedral angles between the mean plane of the piperidine ring and the 4-chlorophenyl and two benzene rings are 83.4 (5), 76.4 (2) and 85.9 (2)°, respectively. The two benzene rings are inclined to one another by 50.8 (6)°. In the crystal, molecules are linked by O-H...O and O-H...N hydrogen bonds and weak C-H...O intermolecular interactions, forming an infinite two-dimensional network along [110].