Ethyl N-(2-benzoyl-3-oxo-3-phenylpropanoyl)carbamate

In the title compound, C19H17NO5, the dihedral angle between the phenyl groups is 79.55 (15)°. The terminal ethoxy group is disordered over two orientations in a 0.873 (6):0.127 (6) ratio. In the crystal, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds into [001] chains which incorporate R 1 2(6) loops. A very weak C—H⋯π contact also occurs.


Related literature
Cg2 is the centroid of the C10-C15 phenyl ring. amide linkage toward hydrolysis is of crucial importance to biological systems, since it allows the construction of peptides from relatively simple amino acid precursors.
In the crystal structure, N-H···O and C-H···O hydrogen bonds (Table 1, Fig. 2) connect the neighbouring molecules, into chains running along the c axis, forming the R 2 1 (6) motifs (Fig. 2). Furthermore, C-H···π interactions between the H19F hydrogen atom of the methyl group and the C10-C15 phenyl ring (with centroid Cg2) is also observed ( Table 1).

Experimental
Dibenzoylaceticacid-N-carboxyethylamide was prepared from reaction of 4-benzoyl-5-phenyl-2,3-furandione and ethyl urethane as the method reported earlier (Fabian et al., 1992). These compounds were refluxed in benzene for 5 h. The solvent was evaporated under reduced pressure to give an oily residue which was treated with ether and finally crystallized from absolute ethanol as colourless needles. Analysis calculated for (C 19 H 17 NO 5 ): C 67.25, H 5.01, N 4.14.
The C atoms of the terminal ethoxy group are disordered over two positions with occupancy ratio 0.873 (6):0.127 (6).
The temperature factors of the disordered C atoms were refined with the EADP restraint.
The unit cell contains a pair of voids of 44 (2)Å 3 volume located about an inversion centre but the residual electron density (highest peak = 0.160 e Å -3 and deepest hole = -0.126 e Å -3 ) in the difference Fourier map suggests that no solvent molecule occupies this void.  The molecular structure of (I) with displacement ellipsoids for non-H atoms drawn at the 30% probability level. Only the major disorder component is shown.

Figure 2
The packing and hydrogen bonding of the title compound, viewing along the b axis. H atoms not involved in hydrogen bonding and the minor disordered component are omitted for clarity.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.