N,N′-Bis[(4-methylphenyl)sulfonyl]adipamide

In the centrosymmetric title compound, C20H24N2O6S2, the N—H and C=O bonds are trans to each other. In the crystal, intermolecular N—H⋯O(S) hydrogen bonds link the molecules into zigzag chains running along the b axis. The O atom involved in the hydrogen bond has a longer S—O bond than the other O atom bonded to S [1.441 (2) versus 1.428 (2) Å].

In the centrosymmetric title compound, C 20 H 24 N 2 O 6 S 2 , the N-H and C O bonds are trans to each other. In the crystal, intermolecular N-HÁ Á ÁO(S) hydrogen bonds link the molecules into zigzag chains running along the b axis. The O atom involved in the hydrogen bond has a longer S-O bond than the other O atom bonded to S [1.441 (2) versus 1.428 (2) Å ].
VZR thanks the University Grants Commission, Government of India, New Delhi, for the award of a research fellowship.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5485).

Comment
The sulfonamide moiety is a constituent of many biologically significant compounds. As a part of studying the effect of substituents on the structures of this class of compounds (Gowda et al., 2005(Gowda et al., , 2007Rodrigues et al., 2011), in the present work, the structure of N,N-bis(4-methylphenylsulfonyl)-adipamide (I) has been determined (Fig.1). The asymmetric unit comprises half of a molecule, the remaining portion being generated via an inversion centre, similar to that observed in N,N-bis(2-methylphenylsulfonyl)-adipamide (II) (Rodrigues et al., 2011). The conformation of the N-H and C=O bonds in the C-SO 2 -NH-C(O)-C-C segment is anti to each other and the amide O atom is also anti to the H atoms attached to the adjacent C atom. The molecule is bent at the S atom with the C-SO 2 -NH-C(O) torsion angle of -58.5 (3)°, compared to the value of -63.7 (4)° in (II). Further, the S1-N1-C7-C8 and C7-N1-S1-O2 segments are nearly linear. The torsion angles C2-C1-S1-N1 and C6-C1-S1-N1 are, respectively, -60.6 (3)° and 120.3 (3)°. The corresponding values in (II) are -71.3 (4)° and 106.9 (4)°, respectively.
The dihedral angle between the planes of the benzene ring and the SO 2 -NH-C(O)-C-C segment in (I) is 72.0 (1)°, compared to the value of 89.9 (1)° in (II).
N-H···O2(S) H-bond formation results in an S=O2 bond longer than the S=O1 bond. A series of N-H···O(S) intermolecular hydrogen bonds (Table 1) link the molecules into infinite chains running in the b-axis direction (Fig. 2).
Experimental N,N-Bis(4-methylphenylsulfonyl)-adipamide was prepared by refluxing a mixture of adipic acid (0.01 mol) with p-toluenesulfonamide (0.02 mol) and POCl 3 for 1 hr on a water bath. The reaction mixture was allowed to cool and added ether to it. The solid product obtained was filtered, washed thoroughly with ether and hot ethanol. The compound was recrystallized to the constant melting point and was characterized by its infrared and NMR spectra.
Needle like colorless single crystals used in the X-ray diffraction studies were grown by a slow evaporation of a solution of the compound in ethanol at room temperature.

Refinement
The H atom of the NH group was located in a difference map and later restrained to the distance N-H = 0.86 (2) Å. All other H atoms were positioned with idealized geometry using a riding model with aromatic C-H distance = 0.93 Å, methylene C-H = 0.97 Å and methyl C-H = 0.96 Å. All H atoms were refined with isotropic displacement parameters set to 1.2 times of the U eq of the parent atom.   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.