Substituent position effect on the crystal structures of N-phenyl-2-phthalimidoethanesulfonamide derivatives

In order to determine the impact of different substituents and their positions on intermolecular interactions and ultimately on the crystal packing, unsubstituted N-phenyl-2-phthalimidoethanesulfonamide, C16H14N2O4S, (I), and the N-(4-nitrophenyl)-, C16H13N3O6S, (II), N-(4-methoxyphenyl)-, C16H16N3O6S, (III), and N-(2-ethylphenyl)-, as the monohydrate, C18H18N2O4S·H2O, (IV), derivatives have been characterized by single-crystal X-ray crystallography. Sulfonamides (I) and (II) have triclinic crystal systems, while (III) and (IV) are monoclinic. Although the molecules differ from each other only with respect to small substituents and their positions, they crystallized in different space groups as a result of differing intra- and intermolecular hydrogen-bond interactions. The structures of (I), (II) and (III) are stabilized by intermolecular N—H...O and C—H...O hydrogen bonds, while that of (IV) is stabilized by intermolecular O—H...O and C—H...O hydrogen bonds. All four structures are of interest with respect to their biological activities and have been studied as part of a program to develop anticonvulsant drugs for the treatment of epilepsy.

Positional isomeric effect on the crystallization of chlorine-substituted N-phenyl-2-phthalimidoethanesulfonamide derivatives

The ortho-, para- and meta-chloro-substituted N-chlorophenyl-2-phthalimidoethanesulfonamide derivatives, C16H13ClN2O4S, have been structurally characterized by single-crystal X-ray crystallography. N-(2-Chlorophenyl)-2-phthalimidoethanesulfonamide, (I), has orthorhombic (P2(1)2(1)2(1)) symmetry, N-(4-chlorophenyl)-2-phthalimidoethanesulfonamide, (II), has triclinic (P1¯) symmetry and N-(3-chlorophenyl)-2-phthalimidoethanesulfonamide, (III), has monoclinic (P2(1)/c) symmetry. The molecules of (I)-(III) are regioisomers which have crystallized in different space groups as a result of the differing intra- and intermolecular hydrogen-bond interactions which are present in each structure. Compounds (I) and (II) are stabilized by N-H···O and C-H···O hydrogen bonds, while (III) is stabilized by N-H···O, C-H···O and C-H···Cl hydrogen-bond interactions. The structure of (II) also displays π-π stacking interactions between the isoindole and benzene rings. All three structures are of interest with respect to their biological activities and have been studied as part of a programme to develop anticonvulsant drugs for the treatment of epilepsy.