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.