Diethyl 2,2′-[(5-dimethylamino-1-naphthyl)sulfonylimino]diacetate

In the title compound, C20H26N2O6S, the N atom of the dimethylamino group is displaced by 0.113 (2) Å from the plane of the naphthalene ring system. The two ethoxy groups adopt zigzag conformations. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link the molecules, forming a three-dimensional network. Both ethyl groups are disordered over two sites with the ratios of refined occupancies being 0.857 (16):0.143 (16) and 0.517 (14):0.483 (14).

In the title compound, C 20 H 26 N 2 O 6 S, the N atom of the dimethylamino group is displaced by 0.113 (2) Å from the plane of the naphthalene ring system. The two ethoxy groups adopt zigzag conformations. In the crystal structure, weak intermolecular C-HÁ Á ÁO hydrogen bonds link the molecules, forming a three-dimensional network. Both ethyl groups are disordered over two sites with the ratios of refined occupancies being 0.857 (16) Table 1 Hydrogen-bond geometry (Å , ). the crystal stucture.
In the molecular structure ( Fig. 1), the N atom of the dimethylamino group is displaced by 0.113 (2) Å from the plane of the naphthalene ring system. The two ethoxycarbonyl groups adopt coiled conformations with C14-O4-C15-C16 and C18-O6-C119-C20 torsion angles of 90.1 (10)° and 159.6 (9)°, respectively. All bond lengths and bond angles are as expected. In the crystal structure ( Fig.2) weak intermolecular C-H···O hydrogen bonds lead to the formation of a three-dimension network.

Experimental
Diethyl iminodiacetate(0.38 g, 2 mmol) was added to a stirred solution of dansyl chloride(0.27 g, 1 mmol) in dry acetonitrile(40 ml). The reaction mixture was allowed to stir for 12 hr at 353 K. The progress of the reaction was monitored by TLC, untill the completion of reaction. The solvent was evaporated and the residue was purified by column chromatography (hexane-ethyl acetate,1:5 v/v) to afford the title compound as a yellow solid. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.
All H atoms were placed in idealized positions [C-H=0.96 Å (methyl), 0.97Å (methylene) and 0.93 Å (aromatic)] and included in the refinement in the riding-model approximation, with U iso (H)= 1.5U eq (methyl C) and 1.2U eq (methylene and aromatic C). Fig. 1. The molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level. The disorder is not shown.

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ.