4-Methylbenzyl 4-aminobenzoate

The dihedral angle between the two benzene rings in the title compound, C15H15NO2, is 65.28 (12)°. The crystal structure is stabilized by N—H⋯N and N—H⋯O hydrogen bonds, leading to the formation of supramolecular chains along the a-axis direction.

The dihedral angle between the two benzene rings in the title compound, C 15 H 15 NO 2 , is 65.28 (12) . The crystal structure is stabilized by N-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds, leading to the formation of supramolecular chains along the aaxis direction.

Comment
Reduction of aryl-nitro compounds to their corresponding amines is an important chemical transformation in synthetic organic chemistry mainly due to the fact that the amino group can serve as the site for further derivatization (Tafesh et al., 1996;Vass et al., 2001). Amines are important intermediates in the production of many pharmaceuticals, photographic materials, agrochemicals, polymers, dyes, and rubber materials (Kumarraja & Pitchumani, 2004). Selective reduction nitro-aromatics to amines can be achieved by hydrogen transfer using Pt-C (Entwistle et al., 1977), Pd-C (Bavin et al., 1958) and Raney Ni (Yuste et al., 1982) catalysts. Most commonly applied or reported methods are direct catalytic hydrogenation and catalytic hydrazine reduction. The reduction of 1,4-bis(4-nitrobenzoyloxymethyl) benzene has been carried out using the catalytic hydrogenation method. It is important to note that the process requires much care in the addition of hydrazine, in order to prevent the breakdown of the ester linkage, as hydrazides may be formed from carboxylic esters in the absence of the catalyst or even if the catalyst is not properly charged (Idrees et al., 2009). The limited addition of the hydrazine in the presence of activated catalyst can also cause the breakage of ester linkage not from the aryl carbon but from the acyl carbon as proved by the crystal structure of the title compound, (I). Herein, the synthesis and the crystal structure of (I) are reported.
The dihedral angle between the two benzene rings in (I) is 65.28 (12)°. The crystal structure is stabilized by N-H···N and N-H···O hydrogen bonds, Table 1, which lead to supramolecular chains along the a direction.

Experimental
Compound (I) was synthesized in two steps. In the first step, a mixture of 1,4-bis(chloromethyl)benzene Aldrich; 2.00 g, 0.0114 mol), anhydrous K 2 CO 3 (3.154 g, 0.0229 mol) and 4-nitrobenzoic acid (3.824 g, 0.0229 mol) were added to a two neck round bottom flask charged with DMF (50 ml). This was heated at 393 K for 12 h under an nitrogen atmosphere. After cooling to room temperature, the reaction mixture was poured into water (800 ml) to precipitate a yellow solid which was washed thoroughly with water and then separated by filtration. In the second step a 250 ml two neck flask was charged with the just synthesised yellow solid (1.00 g, 2.84 mmol) and was refluxed in ethanol with 5% palladium on carbon (Pd/C, 0.06 g), followed by the drop-wise addition of hydrated hydrazine (80%) diluted in ethanol. The mixture was refluxed for 8 h and then filtered to remove Pd/C. The solvent was evaporated and the resulting crude solid was recrystallized from ethanol to afford crystals (yield:68%, m.pt.: 397 K).

Refinement
Hydrogen atoms bonded to C were included in calculated positions [C-H = 0.95-0.99 Å] and refined as riding [U iso (H) = 1.2-1.5U eq (C)]. The H atoms bonded to N were isotropically refined. Due to the absence of anomalous scatterers, the absolute structure could not be determined and 773 Friedel pairs were merged.  Fig. 1. Perspective view of (I) with the atom numbering scheme. The displacement ellipsoids are at the 50% probability level and H atoms are drawn as small spheres of arbitrary radii.

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