SINGLE CRYSTAL X-RAY DIFFRACTION STUDIES OF NBENZENESULFONYL- 2-METHYL-1,2,3,4-TETRAHYDROQUINOLINE

KOMROVSKY, F; N.R.SPERANDEO; MAZZIERI MR; CAIRA, MR

Buenos Aires

Encuentro; VI Reunión de la Asociación Argentina de Cristalografía; 2010

SINGLE CRYSTAL X-RAY DIFFRACTION STUDIES OF NBENZENESULFONYL- 2-METHYL-1,2,3,4-TETRAHYDROQUINOLINE F. Komrovsky (a), N. Sperandeo (a), M.R. Mazzieri (a), M. Caira (b) * (a) Departamento Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre esq. Medina Allende. Ciudad Universitaria. Córdoba. Argentina. CP: 5000. (b) Department of Chemistry, University of Cape Town, Rondebosch 7701. Cape Town. South Africa. RESUMEN Here, we study the crystal structure of N-benzenesulfonyl-2-methyl-1,2,3,4-tetrahydroquinoline (1). Crystals of 1 are crystallized by slow evaporation from ethanol-diethyl ether and the crystal structure is successfully resolved. Its overall molecular conformation can be described by two torsion angles, namely C2-N1-S12-C15 and N1-S12-C15-C16. The conformation observed is maintained by three intramolecular hydrogen bonds, namely C2-H×××O13, C8-H×××O14 and C16-H×××O13. Keywords: N-benzenesulfonyl derivatives of heterocycles, SXRD, Drug design. 1. OBJECTIVE To study the three-dimensional structure of Nbenzenesulfonyl- 2-methyl-1,2,3,4- tetrahydroquinoline (1) by Single-crystal X-ray diffraction (SXRD). 2. CURRENT STATUS SXRD is the most common experimental method to understand the structural characteristics of a compound. Although this structure does not necessarily resemble the molecule present in the biological medium, data coming from those studies are considered as useful information in Drug Design. As part of an ongoing research project [1-3], a library of N-benzenesulfonyl derivatives of heterocycles has been prepared, some of which have presented interesting antiparasitic [1, 2], and antibacterial [3] activities. We are reporting herein the crystal structure of 1, one of the compounds of the library. 3. MATERIALS AND METHODS Solution growth methods were used to obtain single crystals of 1. Therefore, different solvents, temperatures, evaporation rates, and diffusion of anti-solvents were tried. X-ray data were collected on a Nonius Kappa CCD diffractometer with the specimen cooled to 173(2) K in a constant stream of nitrogen to optimize diffraction quality. 4. RESULTS AND DISCUSSION Single crystals of 1 were obtained by slow evaporation of a dilute ethanol-diethyl ether solution. It was found that 1 crystallizes in the monoclinic space group P21/c (No 14) with Z= 4. In the structure of 1 (Fig. 1), the heterocyclic ring adopts a conformation with atoms N1, C9, C10, C4 practically coplanar and atoms C2 and C3 above and below the plane, respectively. Relevant dihedral angles are: N1-C9-C10-C4= -4.2(3)° and N1-C2-C3-C4= 58.9(3)°. The overall molecular conformation can be described by two dihedral angles, namely C2-N1-S12-C15= -77.4(2)°, which defines the benzenesulfonyl moiety position relative to the heterocyclic ring and N1-S12-C15- C16= 104.6(2)° angle, defining the orientation of the benzene ring in relation to the sulfonyl group. This conformation is maintained by three intramolecular hydrogen bonds, namely C2- H×××O13, C8-H×××O14 and C16-H×××O13. Fig. 1. Structure and conformation of 1. Nonhydrogen atoms are represented as thermal ellipsoids drawn at the 40% probability level. Molecules in the crystal are held together primarily by van der Waals interactions. Only a single, weak intermolecular hydrogen bond of type C-H×××O was identified (Fig. 2). Fig. 2. Crystal packing viewed down [100] 5. CONCLUSIONS The crystal structure of 1 (crystallized by slow evaporation from ethanol-diethyl ether) was successfully resolved. Its overall molecular conformation can be described by two torsion angles, namely C2-N1-S12-C15 and N1-S12-C15-C16. This conformation is maintained by three intramolecular hydrogen bonds, namely C2-H×××O13, C8-H×××O14 and C16-H×××O13. 6. REFERENCES 1. R. Pagliero, S. Lusvarghi, A. Pierini, R. Brun, M. Mazzieri, Bioorg Med Chem, 18 (2010), 142. 2. R. Pagliero, A. Pierini, R. Brun, M. Mazzieri, Lett Drug Des Discov, 7 (2010), 461. 3. L. Hergert, M. Nieto, M. Becerra, I. Albesa, M. Mazzieri, Lett Drug Des Discov, 5 (2008), 313.