1-Methyl-3-(naphthalen-1-yl)-3,3a,4,9b-tetra­hydro-1H-chromeno[4,3-c]isoxazole-3a-carbonitrile

Rajeswari Gangadharan; K SethuSankar; Gandhi Murugan; Manickam Bakthadoss

doi:10.1107/S1600536811009731

. 2011 Mar 23;67(Pt 4):o942. doi: 10.1107/S1600536811009731

1-Methyl-3-(naphthalen-1-yl)-3,3a,4,9b-tetrahydro-1H-chromeno[4,3-c]isoxazole-3a-carbonitrile

Rajeswari Gangadharan ^a, K SethuSankar ^b, Gandhi Murugan ^c, Manickam Bakthadoss ^c,^*

PMCID: PMC3099989 PMID: 21754210

Abstract

In the title compound, C₂₂H₁₈N₂O₂, the pyran ring of the chromene unit is fused with an isoxazole ring, which adopts an N-envelope conformation with the N atom lying 1.3291 (14) Å from the mean plane of the remaining ring atoms [maximum deviation = 0.341 (2) Å]. The dihedral angle between the isoxazole and chromene units is 43.74 (8)° and that between the iosxazole ring and the naphthalene ring system is 58.82 (8)°. In the crystal, the molecules are linked by weak C—H⋯π interactions.

Related literature

For uses of isoxazole derivatives, see: Baraldi et al. (1987 ▶); Eddington et al. (2002 ▶); Caine (1993 ▶). For related structures, see: Swaminathan et al. (2011a ▶,b ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For the synthesis of isoxazolidines, see: Bakthadoss & Murugan (2010 ▶).

Experimental

Crystal data

C₂₂H₁₈N₂O₂
M _r = 342.38
Monoclinic,
a = 10.622 (6) Å
b = 12.969 (7) Å
c = 12.423 (7) Å
β = 93.64 (3)°
V = 1707.9 (16) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.30 × 0.25 × 0.20 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
19983 measured reflections
4684 independent reflections
2767 reflections with I > 2σ(I)
R _int = 0.054

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.176
S = 1.03
4684 reflections
236 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811009731/pv2398sup1.cif

e-67-0o942-sup1.cif^{(21.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811009731/pv2398Isup2.hkl

e-67-0o942-Isup2.hkl^{(224.8KB, hkl)}

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

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

Cg4 is the centroid of the C12–C17 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H11C⋯Cg4ⁱ	0.96	2.84	3.477 (2)	125

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Symmetry code: (i) Inline graphic .

Acknowledgments

RG and KS are grateful to Dr Babu Varghese, SAIF, IIT, Madras, for help with the data collection.

supplementary crystallographic information

Comment

Isoxazole and its derivates are key intermediates for the preparation of products which mimic natural compounds (Baraldi et al., 1987). They have been shown to possess anticonvulsant activity (Eddington et al., 2002). Chromenopyrrole compounds are used in the treatment of impulsive disorders (Caine, 1993).

In the title compound (Fig. 1), the isoxazole rings adopts an N1-envelope conformation; N1 lies 1.3291 (14) Å from the mean plane formed by the rest of the ring atoms. The dihedral angle between the isoxazole and chromeno moiety is 43.74 (8)°. The dihedral angle between the isoxazole and naphthalene ring system is 58.82 (8)°, indicating a bisectional orientation. The pyran ring (O1/C1/C6-C9) adopts a half-chair conformation with puckering amplitudes (Cremer & Pople, 1975): Q = 0.480 (2) Å, θ = 129.2 (2)° and φ = 101.2 (2)°. The title compound exhibits structural similarities with other reported structures (Swaminathan et al., 2011a,b). The molecular structure is stabilized by C–H···π interactions (C11–H11C···Cg4 where Cg4 is the centroid of the six membered ring defined by the atoms C12–C17) (Table 1).

Experimental

A mixture of (E)-2-((2-formylnaphthalen-3-yloxy) -3-phenylacrylonitrile (1 mmol), N-methylhydroxyamine hydrochloride (1.1 mmol), pyridine (0.24 mL, 3 mmol) and ethanol (5 mL) was placed in a round bottom flask and refluxed for 6 h. After completion of the reaction as indicated by TLC the reaction mixture was concentrated under reduced pressure. The crude product was diluted with water (10 ml), dilute HCl (5 mL) and extracted with ethylacetate (20 ml). The organic layer was washed with brine solution (10 ml) and concentrated. The crude product was purified by column chromatography to provide the pure title compound as colourless solid. Crystals of the title compound were grown from its solution in methanol by slow evaporation at room temperature.