Crystal structures of two 1,3-thiazolidin-4-one derivatives featuring sulfide and sulfone functional groups

The crystal structures of two closely related compounds, 1-cyclohexyl-2-(2-nitrophenyl)-1,3-thiazolidin-4-one, C15H18N2O3S, (1) and 1-cyclohexyl-2-(2-nitrophenyl)-1,3-thiazolidin-4-one 1,1-dioxide, C15H18N2O5S, (2), are presented. These compounds are comprised of three types of rings: thiazolidinone, nitrophenyl and cyclohexyl. In both structures, the rings are close to mutually perpendicular, with interplanar dihedral angles greater than 80° in each case. The thiazolidinone rings in both structures exhibit envelope puckering with the S atom as flap and the cyclohexyl rings are in their expected chair conformations. The two structures superpose fairly well, except for the orientation of the nitro groups with respect to their host phenyl ring, with a difference of about 10° between 1 and 2. The extended structure of 1 has two kinds of weak C—H...O interactions, giving rise to a closed ring formation involving three symmetry-related molecules. Structure 2 has four C—H...O interactions, two of which are exclusively between symmetry-related thiazolidinone dioxide moieties and have a parallel `give-and-take-fashion' counterpart. In the other two interactions, the nitrophenyl ring and the cyclohexane ring each offer an H atom to the two O atoms on the sulfone group. Additionally, a C—H...π interaction between a C—H group of the cyclohexane ring and the nitrophenyl ring of an adjacent molecule helps to consolidate the structure