5-Methyl-3-phenyl­isoxazole-4-carb­oxy­lic acid

Chandra; N Srikantamurthy; G J Vishalakshi; S Jeyaseelan; K B Umesha; M Mahendra

doi:10.1107/S1600536813011410

. 2013 May 15;69(Pt 6):o897. doi: 10.1107/S1600536813011410

5-Methyl-3-phenylisoxazole-4-carboxylic acid

Chandra ^a, N Srikantamurthy ^b, G J Vishalakshi ^a, S Jeyaseelan ^c, K B Umesha ^b, M Mahendra ^a,^*

PMCID: PMC3685054 PMID: 23795073

Abstract

In the title compound, C₁₁H₉NO₃, the phenyl and isoxazole rings form a dihedral angle of 56.64 (8)°. The carboxy group is almost in the same plane as the isoxazole ring with a C—C—C—O torsion angle of −3.3 (2)°. In the crystal, pairs of O—H⋯O hydrogen bonds link the molecules into head-to-head dimers. C—H⋯N hydrogen bonds and π–π stacking interactions between phenyl rings [centroid–centroid distance = 3.9614 (17)Å] link the dimers into a three-dimensional network.

Related literature

For the biological and pharmaceutical importance of isoxazoles, see: Basappa et al., (2003 ▶); Conti et al. (1998 ▶); Kang et al. (2000 ▶); Lee et al. (2009 ▶); Shin et al. (2005 ▶); Stevens & Albizati (1984 ▶). For bond-length and angle data in related structures, see: Wolf et al. (1995 ▶); Chandra et al., (2013 ▶).

Experimental

Crystal data

C₁₁H₉NO₃
M _r = 203.19
Monoclinic,
a = 11.953 (4) Å
b = 5.981 (2) Å
c = 14.142 (5) Å
β = 105.548 (6)°
V = 974.0 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 273 K
0.30 × 0.25 × 0.20 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
8619 measured reflections
1712 independent reflections
1558 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.111
S = 1.05
1712 reflections
138 parameters
H-atom parameters constrained
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Click here for additional data file.^{(17.4KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813011410/bg2504sup1.cif

e-69-0o897-sup1.cif^{(17.4KB, cif)}

Click here for additional data file.^{(84.4KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813011410/bg2504Isup2.hkl

e-69-0o897-Isup2.hkl^{(84.4KB, hkl)}

Click here for additional data file.^{(3.9KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813011410/bg2504Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O14—H14⋯O15ⁱ	0.82	1.81	2.6252 (18)	172
C11—H11A⋯N8ⁱⁱ	0.96	2.51	3.427 (2)	159

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors would like to thank the UGC, New Delhi, Government of India, for awarding a project under the head F·No.41–920/2012(SR) dated: 25–07-2012.

supplementary crystallographic information

Comment

Isoxazole derivatives bearing various substituents are known to have diverse biological and pharmaceutical activities; such as anti-tumor (Kang et al., 2000), antiviral (Lee et al., 2009), hypoglycemic (Conti et al., 1998), antifungal (Basappa et al., 2003) and anti-HIV activities (Shin et al., 2005). In addition, isoxazoles and related compounds have attracted much interest because of their fungicidal, plant-growth regulating and antibacterial activities (Stevens & Albizati, 1984). As part of our interest in these compounds and our extensive background on isoxazole derivatives, we have synthesized the title compound to study its crystal structure.

Fig. 1 presents an ellipsoid plot of the title compound (I). The (C7/N8/O9/C10/C12) isoxazole ring is in Syn-Clinal conformation with respect to the (C1-C2-C3-C4-C5-C6) phenyl ring, as indicated by the (C1-C6-C7-N8) torsion angle of -54.40 (19)°. The carboxylic acid group at C12 is almost in the same plane as the isoxazole ring (C7-C12-C13-O15 torsion angle = -3.3 (2)°). The bond lengths and angles are within normal ranges and are comparable to related structure (Wolf et al., 1995 & Chandra et al., 2013). The crystal structure is stabilized by O—H···O bonds (Table 1), which define head to head dimers, and weaker C-H···N bonds (Table 1), thus defining planes parallel to (101) (Fig 2). Finally, there are π···π stacking interacions between phenyl rings with Cg···Cg[1-x,1-y,-z] and slippage displacement distances of 3.9614 (17)Å and 1.284Å respectively (Fig 3) which link planes into a 3D structure.

Experimental

A mixture of benzaldehyde oxime (1 mmol), ethyl acetoacetate (2 mmol) and anhydrous zinc chloride (0.1 mmol) were taken in a 10 ml round bottomed flask and the contents were gradually heated to 60°C without any solvent for about one hour. After completion of the reaction (as indicated by TLC), the mixture was cooled to room temperature and ethanol was added with stirring for about 30 min. The solid ethyl 5-methyl-3-phenylisoxazole-4-carboxylate thus obtained was treated with 5% NaOH (10 ml) at room temperature for about 4hr. After completion of the reaction (as indicated by TLC), the reaction mixture was acidified with 2 N HCl. The solids thus obtained were filtered and recrystalized from hot ethanol to get crystals of the title compound.