N,N-Dibenzyl-4-methylbenzenesulfonamide

The asymmetric unit of the title compound, C21H21NO2S, comprises two molecules with similar conformations. The benzene rings of the nitrogen-bound benzyl groups lie to the same side of the molecule but are splayed in opposite directions precluding π–π interactions between them. In the crystal, each independent molecule self-associates via intermolecular C—H⋯O interactions, forming a supramolecular chain propagating along the b axis.

Each independent molecule self-associates into a supramolecular chain along the b axis that is sustained by C-H···O contacts, Table 1. A view of one such chain is shown in Fig. 4.

Experimental
A mixture of N-benzyl-4-methylbenzenesulfonamide (0.5 g, 2.02 mmol), sodium hydride (0.2 g, 8.333 mmol) and N,N-dimethylformamide (10 ml) was stirred at room temperature for 30 min. followed by the addition of benzyl chloride (0.23 ml, 2.02 mmol). After complete consumption of reactants (as monitored by TLC), the contents were poured over crushed ice.
The precipitated product was isolated, washed and recrystallized from methanol solution to yield colourless blocks of (I).

Refinement
The H atoms were geometrically placed (C-H = 0.93-0.97 Å) and refined as riding with U iso (H) = 1.2-1.5U eq (C). Fig. 1. The molecular structure of the first independent molecule in (I) showing displacement ellipsoids at the 35% probability level.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.
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 > 2σ(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.