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, C(15)H(18)N(2)O(3)S, (1) and 1-cyclo­hexyl-2-(2-nitro­phen­yl)-1,3-thia­zolidin-4-one 1,1-dioxide, C(15)H(18)N(2)O(5)S, (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.