Methyl 3-phenylisoxazole-5-carboxylate

In the title compound, C11H9NO3, the dihedral angle between the isoxazole and phenyl rings is 19.79 (12), while the ester group is inclined to the isoxazole group by 12.14 (6)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming layers lying parallel to (010).

In the title compound, C 11 H 9 NO 3 , the dihedral angle between the isoxazole and phenyl rings is 19.79 (12), while the ester group is inclined to the isoxazole group by 12.14 (6) . In the crystal, molecules are linked by C-HÁ Á ÁO hydrogen bonds, forming layers lying parallel to (010).

Comment
The wide occurrence of heterocycles, such as isoxazoles, in bioactive natural products, pharmaceuticals and agrochemicals has made them important synthetic targets. They are of great importance in biological chemistry, showing anticancer activity, and substituted isoxazoles have revealed antibacterial, antioxidant, insecticidal properties (Musad et al., 2011). Here we report on the crystal structure of the title isoxazole derivative, synthesized by alcoholysis of 3-Phenylisoxazole-5-carbonyl chloride in dichloromethane.
In the molecule of the title compound, Fig. 1, the dihedral angle between the phenyl and the isoxazole rings is 19.79 (12) °. This is larger than that of 7.37 (19)° observed in the related compound Isopropyl 3-phenylisoxazole-5carboxylate (Wang et al., 2013), but the bond lengths within the isoxazole ring are the same.
In the crystal, molecules are linked by C-H···O hydrogen bonds (Table 1), forming layers lying parallel to (010).

Experimental
3-Phenylisoxazole-5-carboxylic acid (10 mmol, 1.95 g; Wang et al., 2013) was dissolved in 100 ml dichloromethane, then thionyl chloride (12 mmol, 1.43 g) was added drop wise while the solution was stirred for 20 minutes in an ice bath. The solvent was removed under reduced pressure and the mixture was used for the next step without further purification.
Methanol (20 mmol, 0.64 g) was then added and the mixture stirred for 6 h at room temperature. The resulting residue was purified as a white solid (1.54 g; 76% yield). Recrystallization in dichloromethane gave fine colourless plate-like crystals suitable for X-ray diffraction analysis.

Refinement
All H atoms were placed in idealized positions and allowed to ride on the respective parent atom: C-H = 0.93-0.96 Å with U iso (H) = 1.5U eq (C-methyl) and = 1.2U eq (C) for other H atoms.

Computing details
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009)   The molecular structure of the title molecule, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity. Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.