4-[(4-Methylbenzenesulfonamido)methyl]cyclohexanecarboxylic acid

The title compound, C15H21NO4S, crystallized with two independent molecules in the asymmetric unit in which the dihedral angles between the mean planes of the benzene and cyclohexane rings are 78.3 (2) and 67.6 (2)°. The substituents of the cyclohexyl rings are in equatorial orientations. In the crystal, both molecules form R 2 2(6) carboxylic acid inversion dimers via pairs of O—H⋯O hydrogen bonds. Further N—H⋯O and C—H⋯O interactions generate a three-dimensional network.

The title compound, C 15 H 21 NO 4 S, crystallized with two independent molecules in the asymmetric unit in which the dihedral angles between the mean planes of the benzene and cyclohexane rings are 78.3 (2) and 67.6 (2) . The substituents of the cyclohexyl rings are in equatorial orientations. In the crystal, both molecules form R 2 2 (6) carboxylic acid inversion dimers via pairs of O-HÁ Á ÁO hydrogen bonds. Further N-HÁ Á ÁO and C-HÁ Á ÁO interactions generate a three-dimensional network.

Comment
Tranexamic acid, is a synthetic amino acid that is used commonly for curing abnormal bleeding in a variety of diseases (Boylan et al., 1996;Nilsson, 1980). Number of Scientists derivatized this drug, evaluated their activities and found most of them superior to the parent drug (Svahn et al., 1986;Khan et al., 2002;Vávrová et al., 2005;Shahzadi et al., 2007;Shah et al., 2010).
Experimental 4-toluenesulfonyl chloride (1.21 g, 6.36 mmol) was added to the solution of tranexamic acid (1.0 g, 6.36 mmol) in distilled water (10 ml). The reaction mixture was stirred at room temperature at pH 8-9, which was adjusted by 1 M sodium carbonate solution. After completion of the reaction which was observed by the consumption of 4-toluenesulfonyl chloride, the pH was adjusted at 2-3 using 1 N HCl solution, which results the formation of precipiates, which were filtered off and dried.
The product was recrystallized using methanol to yield colourless plates of (I).

Refinement
The N and O-bound H atoms were located in a difference Fourier map and their positional parameters were restrained [N1-H1N = 0.86 (3), N2-H2N = 0.84 (3), O4-H4O = 0.84 (4) and O7-H7O = 0.81 (4) Å]. Their displacement parameters were refined using a riding model, with U iso (H) = 1.2U eq (N) or 1.5U eq (O). The remaining H atoms were placed at calculated positions and allowed to ride on their carrier atoms with C-H = 0.93 -0.98 Å, and U iso = 1.2U eq (C) for CH and CH 2 groups and U iso = 1.5U eq (C) for CH 3 group. Fig. 1. View of the two independent molecules in the asymmetric unit with displacement ellipsoids for non-H atoms drawn at the 30% probability level.