(E)-Dimethyl 2-(6-benzoyl-7-hydroxy-4-methoxycarbonyl-2-oxo-2H-chromen-8-yl)but-2-enedioate

The molecule of the title compound, C24H18O10, a previously unknown coumarin derivative, contains methoxycarbonyl, 2-butenedioate and benzoyl groups aligned at angles of 28.04 (2), 76.89 (3) and 42.48 (13)°, respectively, to the plane of the coumarin ring system. Intramolecular O—H⋯O hydrogen bonding between hydroxy and carbonyl groups and weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure. The two carbon atoms and attached H atom of the ethylene bond are disordered over two positions, with site occupancy factors of ca 0.9 and 0.1.

The molecule of the title compound, C 24 H 18 O 10 , a previously unknown coumarin derivative, contains methoxycarbonyl, 2butenedioate and benzoyl groups aligned at angles of 28.04 (2), 76.89 (3) and 42.48 (13) , respectively, to the plane of the coumarin ring system. Intramolecular O-HÁ Á ÁO hydrogen bonding between hydroxy and carbonyl groups and weak intermolecular C-HÁ Á ÁO hydrogen bonding is present in the crystal structure. The two carbon atoms and attached H atom of the ethylene bond are disordered over two positions, with site occupancy factors of ca 0.9 and 0.1.
Data collection: SMART (Bruker, 1998); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL. uses in the perfumery industry, as avour enhancers, sunscreens, laser dyes (Khalfan et al., 1987) and in the pharmaceutical industry (Hooper et al., 1982;Morris & Russell, 1971). We have recently synthesized a series of 7-hydroxy coumarins based on a direct, efficient and operationally convenient approach. This paper reports the synthesis and structure of the title compound, which is one of the products of this reaction.

Experimental
To a magnetically stirred solution of 2,4-dihydroxy benzophenone (0.43 g, 2 mmol) and triphenylphosphine (0.52 g, 2 mmol) in 10 ml CH 2 Cl 2 was added dropwise at 263 K over 10 min dimethyl acetylenedicarboxylate (0.45g, 2 mmol). The reaction mixture was then allowed to warm up to room temperature and stand for 48 h. The solvent was removed under reduced pressure and the residue was separated by silica gel column chromatography (Merck 230-400 mesh) using n-hexane-ethyl acetate as eluent. The single crystals of the title compound were obtained form the n-hexane-ethyl acetate solution. Anal.

Refinement
The ethylene of the dimethyl fumarate moiety is disordered over two sites; occupancies were initially refined and converged to ca 0.867:0.133, and fixed as 0.85:0.15 at final cycles of refinement. The hydroxyl H atom was located in a difference Fourier map and refined isotropically. Other H atoms were placed in calculated positions and refined in riding model with the U iso (H) = 1.5U eq (C) (methyl) or 1.2U eq (C) (others). In absence of significant anomalous scattering effects, Friedel pairs were merged. (E)-Dimethyl 2-(6-benzoyl-7-hydroxy-4-methoxycarbonyl-2-oxo-2H-chromen-8-yl)but-2-enedioate Cell parameters from 557 reflections a = 9.2661 (17)

Data collection
Bruker SMART 1000 CCD area-detector diffractometer 2864 independent reflections  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 > 2sigma(F 2 ) is used only for calculating R-factors(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.