Experimental

R factor = 0.047; wR factor = 0.123; data-to-parameter ratio = 15.2. The asymmetric unit of the title compound, C14H14N2O4S, consists of two crystallographically independent molecules. The molecules are twisted at the S—N bonds with C—S—N— C torsion angles of 44.2 (3) and 49.3 (3). The dihedral angles between the benzene rings in the two molecules are 71.53 (7) and 72.11 (7). The amide H atoms exhibit bifurcated intra- and intermolecular hydrogen bonds; the intramolecular N—H O(N) hydrogen bonds generate S(7) motifs. In the crystal, the independent molecules are separately connected through the intermolecular N—H O(S) hydrogen bonds, generating a C(4) motif and a helical chain along the b axis for one molecule and an R2 2(8) motif and an inversion dimer for the other. The crystal studied was a pseudo-merohedral twin with twin law (100/010/001), the refined ratio of the twin domains being 0.7876 (12):0.2124 (12). Related literature For studies on the effects of substituents on the structures an