RESUMEN
The structure of (R)-rasagiline mesylate [(R)-RasH+·Mes-], an active pharmaceutical ingredient used to treat Parkinson's disease, is presented. The structure was determined from laboratory and synchrotron powder diffraction data, refined using the Rietveld method, and validated and optimized using dispersion-corrected DFT calculations. The unit-cell parameters obtained in both experiments are in good agreement and the refinement with both datasets converged to good agreement factors. The final parameters obtained from laboratory data were a = 5.4905â (8), b = 6.536â (2), c = 38.953â (3)â Å, V = 1398.0â (4)â Å3 and from synchrotron powder data were a = 5.487530â (10)â Å, b = 6.528939â (12)â Å, c = 38.94313â (9)â Å, V = 1395.245â (5)â Å3 with Z = 4 and space group P212121. Preferred orientation was properly accounted for using the synchrotron radiation data, leading to a March-Dollase parameter of 1.140â (1) instead of the 0.642â (1) value obtained from laboratory data. In the structure, (R)-RasH+ moieties form layers parallel to the ab plane connected by mesylate ions through N-H...O and C-H...O hydrogen bonds. These layers stack along the c axis and are further connected by C-H...π interactions. Hirshfeld surface analysis and fingerprint plot calculations indicate that the main interactions are: H...H (50.9%), H...C/C...H (27.1%) and H...O/O...H (21.1%).
RESUMEN
The structure of racemic (RS)-trichlorme-thia-zide [systematic name: (RS)-6-chloro-3-(di-chloro-meth-yl)-1,1-dioxo-3,4-di-hydro-2H-1λ6,2,4-benzo-thia-di-azine-7-sulfonamide], C8H8Cl3N3O4S2 (RS-TCMZ), a diuretic drug used in the treatment of oedema and hypertension, was determined from laboratory X-ray powder diffraction data using DASH [David et al. (2006 â¸). J. Appl. Cryst. 39, 910-915.], refined by the Rietveld method with TOPAS-Academic [Coelho (2018 â¸). J. Appl. Cryst. 51, 210-218], and optimized using DFT-D calculations. The extended structure consists of head-to-tail dimers connected by π-π inter-actions which, in turn, are connected by C-Clâ¯π inter-actions. They form chains propagating along [101], further connected by N-Hâ¯O hydrogen bonds to produce layers parallel to the ac plane that stack along the b-axis direction, connected by additional N-Hâ¯O hydrogen bonds. The Hirshfeld surface analysis indicates a major contribution of Hâ¯O and Hâ¯Cl inter-actions (32.2 and 21.7%, respectively). Energy framework calculations confirm the major contribution of electrostatic inter-actions (E elec) to the total energy (E tot). A comparison with the structure of S-TCMZ is also presented.
RESUMEN
The title heterocyclic compound, C20H27N, has been prepared in good yield (72%) via a BiCl3-catalyzed cationic Povarov reaction between N-propargyl-4-methyl-aniline and (±)-citronellal. The X-ray single-crystal study indicates that the structure consists of mol-ecules connected by C-Hâ¯π contacts to produce chains, which pack in a sandwich-herringbone fashion along the b-axis direction. Hirshfeld surface analysis indicates that Hâ¯H inter-actions dominate by contributing 79.1% to the total surface. Energy frameworks and DFT calculations indicate a major contribution of dispersive forces to the total inter-action energy.
RESUMEN
The title compound, C(16)H(15)N(3), shows a hindrance effect between adjacent amino and methyl groups that leads to a structural distortion, which is reflected in the non-planarity of the quinoline entity and in the bond angles and distances. The crystal packing consists of chains along the b axis sustained by an intermolecular hydrogen bond between the amino group and the N atom of the pyridyl ring.