Crystal structure of 2-(4-acetylanilino)-2-oxoethyl 3-(4-hydroxyphenyl)propionate

In the crystal of the title compound, a supramolecular sheet structure is formed through N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds.


Chemical context
Hydroxy-substituted aromatic compounds with additional ester and amide functionalities have been reported to be potential tyrosinase inhibitors (Miliovsky et al., 2013;Takahashi & Miyazawa, 2011). Tyrosinase is a key enzyme present in melanocytes, which is involved in the biosynthesis of melanin. The abnormal production and accumulation of melanin causes a number of hyperpigmentation disorders such as freckles, melasma, lentigo senilis and pigmented acne scars (Lynde et al., 2006;Cullen, 1998). Tyrosinase has also been linked to melanoma, a skin-cancer type that arises from the aberrant proliferation of melanocytes (Uong & Zon, 2010). It has also been reported that tyrosinase is one of the main causes of most fruit and vegetable damage during post-harvest handling and processing, leading to quicker degradation and shorter shelf life (Yi et al., 2010). Therefore, the synthesis of safe and effective tyrosinase inhibitors is of great concern in the medical, agricultural and cosmetic industries. The synthesis and tyrosinase inhibitory activity of hydroxy-substituted phenyl esters is currently an ongoing research topic in our lab (Ashraf et al., 2015). In view of the tyrosinase inhibitory potential of hydroxy-substituted aromatic compounds, the title compound ( Fig. 1) has been synthesized and characterized by single crystal X-ray diffraction. ISSN 2056-9890

Figure 1
The molecular structure of the title compound, showing the atomnumbering scheme and 30% probability ellipsoids. Only the major occupancy disorder component is shown.

Synthesis and crystallization
The title compound was synthesized by direct condensation of 4-hydroxyphenyl propanoic acid with N-(4-acetylphenyl)-2chloroacetamide in the presence of dimethyl formamide (DMF) solvent and triethylamine base (Fig. 4). The reaction mixture was stirred overnight at room temperature. Then the mixture was poured into finely crushed ice and extracted with ethyl acetate. It was washed with 5% HCl and 5% sodium hydroxide, and finally with aqueous NaCl solution. The organic layer was dried over anhydrous magnesium sulfate, filtered and the solvent was removed under reduced pressure to afford the crude product. The title compound was purified by silica gel column chromatography using ethyl acetate and n-hexane (3:1) as eluent. The single crystals were obtained from a solvent mixture of ethyl acetate/n-hexane (3:1) upon slow evaporation at room temperature (yield 78%, m.p. 419-

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The 4-hydroxyhydrocinnamate fragment, O16/O25/C15-C24, was found to be disordered over two positions and the occupancy ratio was refined to 0.729 (12) Part of the packing diagram of the title compound, showing the C-HÁ Á ÁO hydrogen bonds (dashed lines) between the hydrogen-bonded sheets. Only the major disorder components are shown.

2-(4-Acetylanilino)-2-oxoethyl 3-(4-hydroxyphenyl)propionate
Crystal data 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.