3,4-Dihydroxy-phenyl 3,4,5-trimethoxy-benzoate.

In the title compound, C(16)H(16)O(7), the dihedral angle between the two benzene rings is 82.02 (7)°. The crystal structure is stabilized by inter-molecular O-H⋯O hydrogen bonds, which link the mol-ecules into a two-dimensional network.

In the title compound, C 16 H 16 O 7 , the dihedral angle between the two benzene rings is 82.02 (7) . The crystal structure is stabilized by intermolecular O-HÁ Á ÁO hydrogen bonds, which link the molecules into a two-dimensional network.

Crystal data
Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999). X-ray data were collected at the Center for Research Facilities in Chungnam National University. This work was partially supported by the New Universities for Regional Innovation fund (05-Na-A-01) from the Ministry of Education and Human Resources Department, Republic of Korea.  (Nerya et al., 2003;Dawley et al., 1993;Maeda et al., 1991) are containing hydroxyl (Lee et al., 2007), aromatic, alkene, carbonyl and ether inside their structure and acting as a specific functional group to make the skin white by inhibiting the produce of melanin. In the course of our work on the development of new whitening agents, to complement the inadequacy of current whitening agents and maximize the inhibitory effects of melanin creation, we have synthesized the title compound. Herein we report the molecular and crystal structure of 3,4-dihydroxyphenyl 3,4,5-trimethoxybenzoate ( Fig. 1).

Experimental
The synthesis of the title compound started from sesamol (1 mmol) in THF and 3,4,5-trimethoxybenzoyl chloride (1.2 mmol) with NaH(1.5 mmol) as a catalyst by nucleophilic acyl substitution, then the deprotection of methylenedioxy group was accomplished by treatment of Pb(OAc)4 (1.5 mmol) in refluxing benzene, which generated the intermediate alkoxylated ester.
Hydrolysis of alkoxylated ester in aqueous acetic acid gave a mixture as yellowish oil. The mixture was chromatographed on silica gel (30/1 = dichloromethane/ethyl acetate) to give the title compound as light yellow solid (61.8%, m.p. 408 K). Single crystals were obtained by slow evaporation from a solution of the title compound in ethyl acetate at room temperature.

Refinement
Atoms H6O and H7O of the OH group were found in a difference Fourier map and refined freely with an isotropic displacement parameter. The other H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å for aromatic H atoms and 0.96 Å for methyl H atoms, and with U iso (H) = 1.2U eq (C) for aromatic and 1.5U eq (C) for methyl H atoms.