6-Methoxy-4-methyl-2H-chromen-2-one

The whole molecule of the title coumarin derivative, C11H10O3, is approximately planar, with a maximum deviation of 0.116 (3) Å from the least-squares plane defined by all non-H atoms. In the crystal, adjacent molecules are linked into chains along [011] via intermolecular C—H⋯O hydrogen bonds.

The whole molecule of the title coumarin derivative, C 11 H 10 O 3 , is approximately planar, with a maximum deviation of 0.116 (3) Å from the least-squares plane defined by all non-H atoms. In the crystal, adjacent molecules are linked into chains along [011] via intermolecular C-HÁ Á ÁO hydrogen bonds.

Comment
Coumarin is the mother-nuclear structure of many natural products and the importance of coumarin and its analogous compounds which exhibit useful pharmaceutical activities are well-known. Some substituted coumarin and their derivatives have been reported as food constituents, anti-oxidants, stabilizers, immunomodulatory substances, inhibitors of some enzymes, fluorescent markers in analysis, lasers, and in clinical use (Parvez & Hadda, 2010;Maresca et al., 2010;Grimm & Girard, 2006). In addition, 4-substituted coumarins have shown many pharmaceutical activities such as anti-bacterial, anti-fungal, anthelmintic, insecticidal, hypnotic and other biological activities, and most precisely 4-methyl-coumarins have been correlated to several beneficial pharmacological effects too (Yao & Deng, 2000;Raj & Wenge, 1998). In view of the importance of the coumarin derivatives, the crystal structure of the title compound is reported in this paper.
The title coumarin derivative ( Fig. 1) has an approximately planar molecular structure, with the methoxy-O atom (C10) deviating -0.116 (3) Å from the least-squares plane defined by all non-hydrogen atoms. All bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to those related coumarin structures (Asad et al., 2010;Saidi et al., 2007). In the crystal packing (Fig. 2), adjacent molecules are linked into one-dimensional chains propagating along the [011] direction via intermolecular C8-H8A···O2 hydrogen bonds.
The compound was purified by flash column chromatography. Good quality single crystals suitable for X-ray analysis were obtained from slow evaporation of a 1:1 solution of acetone and petroleum ether.

Refinement
All hydrogen atoms were placed in their calculated positions, with C-H = 0.93 or 0.96 Å, and refined using a riding model, with U iso (H) = 1.2 or 1.5U eq (C). The rotating group model was applied to the methyl groups. Fig. 1. The molecular structure of the title coumarin derivative, showing the atomic numbering scheme. Displacement ellipsoids for non-hydrogen atoms are drawn at the 50 % probability level.

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.