supplementary materials


is5259 scheme

Acta Cryst. (2013). E69, o664    [ doi:10.1107/S1600536813008635 ]

rac-Methyl 3-(2-methoxyphenyl)-3a,4-dihydro-3H-chromeno[4,3-c]isoxazole-3a-carboxylate

S. Paramasivam, J. Srinivasan, P. R. Seshadri and M. Bakthadoss

Abstract top

The title compound, C19H17NO5, comprising two stereogenic C atoms of the same configuration, crystallizes in a centrosymmetric space group as a racemate. The pyran ring adopts a half-chair conformation, while the isoxazole ring adopts an envelope conformation with the C atom bonded to the methoxyphenyl group as the flap. The dihedral angle between the mean plane of the pyran ring and the adjacent benzene ring is 5.86 (5)°. In the crystal, molecules are linked by a weak C-H...O hydrogen bond, forming a chain along the a axis.

Comment top

As a continuation of our research related to isoxazole containing chromenoisoxazole moiety, we analyzed the crystal structure of rac-methyl 3-(2-methoxyphenyl)-1-phenyl-3,3a,4,9b- tetrahydro-1H-chromeno[4,3-c]isoxazole-3a-carboxylate (Paramasivam et al., 2012). The present compound exhibits the pronounced similarity to the previous ones, either in bond lengths and angles as well as in molecular conformation. Isoxazole derivative is used for the treatment of rheumatoid arthritis (Rozman et al., 2002) whereas benzopyran derivatives exhibit anti-depressant activities (Winn et al., 1976) and in the treatment of impulsive-disorder disease (Caine, 1993). On this grounds, the title compound was chosen for X-ray structure analysis (Fig. 1).

The pyran ring (O1/C1/C6–C9) adopts a half-chair conformation with the puckering parameters (Cremer & Pople, 1975) being q2 = 0.395 (1) Å, q3 = -0.296 (1) Å, QT = 0.494 (1) Å and the five-membered ring isoxazole (O2/N1/C7/C8/C12) adopts an envelope conformation with atom C12 as the flap, with puckering parameters being q2 = 0.246 (1) Å and Φ2 = 143.9 (3)°. The dihedral angle between the pyran and the benzene ring (C1–C6) is 5.86 (5)°. Also the dihedral angle between the chromeno ring (fusion of benzene and pyran rings) and isoxazole ring is 11.87 (5)°. In the chromenoisoxazole moiety, the dihedral angle between the benzene and isoxazole ring is 7.71 (6)°. The dihedral angle between the pyran and isoxazole ring is 13.40 (5)°. The geometric parameters of the title compound agree well with the reported similar structure (Paramasivam et al., 2012). The crystal packing is stabilized by C—H···O hydrogen bonds (Table 1).

Related literature top

For the biological activity of isoxazole and benzpyran derivatives, see: Winn et al. (1976); Rozman et al. (2002); Caine (1993). For conformational analysis and puckering parameters, see: Cremer & Pople, (1975). For a related structure, see: Paramasivam et al. (2012).

Experimental top

A solution of (E)-methyl 2-({2-[(E)-(hydroxyimino)methyl]phenoxy}methyl)-3-(2-methoxyphenyl)acrylate (2 mmol) in CCl4 at 0–10 °C was added pinch wise NCS (4 mmol) over 3 h. After Et3N (4 mmol) was added the reaction mixture was stirred at room temperature for 2 h. After completion of the reaction, reaction mixture was evaporated under reduced pressure and the resulting crude mass was diluted with water (15 ml) and extracted with ethyl acetate (3 × 15 ml). The combining organic layer was washed with brine (2 × 10 ml) and dried over anhydrous Na2SO4. The organic layer was evaporated and purified by column chromatography (silica gel 60–120 mesh 7% EtOAc in hexanes) to provide the desired pure product methyl 3-(2-methoxyphenyl)-3a,4-dihydro-3H-chromeno[4,3-c]isoxazole-3a-carboxylate as a colorless solid.

Refinement top

Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms, with C—H = 0.93–0.97 Å and with Uiso(H) = 1.5Ueq(C) for methyl H atoms and 1.2Ueq(C) for other H atoms.

Computing details top

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: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atom-numbering scheme and displacement ellipsoids drawn at the 20% probability level.
rac-Methyl 3-(2-methoxyphenyl)-3a,4-dihydro-3H-chromeno[4,3-c]isoxazole-3a-carboxylate top
Crystal data top
C19H17NO5Z = 2
Mr = 339.34F(000) = 356
Triclinic, P1Triclinic
Hall symbol: -P 1Dx = 1.333 Mg m3
a = 9.4804 (4) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.6401 (4) ÅCell parameters from 3462 reflections
c = 10.7013 (5) Åθ = 2.1–26.4°
α = 81.308 (2)°µ = 0.10 mm1
β = 67.801 (2)°T = 298 K
γ = 69.085 (2)°Block, colourless
V = 845.71 (6) Å30.30 × 0.25 × 0.20 mm
Data collection top
Bruker SMART APEXII area-detector
diffractometer
3462 independent reflections
Radiation source: fine-focus sealed tube3012 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
ω and φ scansθmax = 26.4°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 1111
Tmin = 0.971, Tmax = 0.981k = 1112
12631 measured reflectionsl = 1313
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.040H-atom parameters constrained
wR(F2) = 0.112 w = 1/[σ2(Fo2) + (0.0548P)2 + 0.182P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
3462 reflectionsΔρmax = 0.22 e Å3
229 parametersΔρmin = 0.19 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.093 (6)
Crystal data top
C19H17NO5γ = 69.085 (2)°
Mr = 339.34V = 845.71 (6) Å3
Triclinic, P1Z = 2
a = 9.4804 (4) ÅMo Kα radiation
b = 9.6401 (4) ŵ = 0.10 mm1
c = 10.7013 (5) ÅT = 298 K
α = 81.308 (2)°0.30 × 0.25 × 0.20 mm
β = 67.801 (2)°
Data collection top
Bruker SMART APEXII area-detector
diffractometer
3462 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
3012 reflections with I > 2σ(I)
Tmin = 0.971, Tmax = 0.981Rint = 0.030
12631 measured reflectionsθmax = 26.4°
Refinement top
R[F2 > 2σ(F2)] = 0.040H-atom parameters constrained
wR(F2) = 0.112Δρmax = 0.22 e Å3
S = 1.04Δρmin = 0.19 e Å3
3462 reflectionsAbsolute structure: ?
229 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 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 (Å2) top
xyzUiso*/Ueq
C10.76808 (16)0.07314 (16)0.63411 (13)0.0495 (3)
C20.7901 (2)0.0399 (2)0.55433 (17)0.0684 (5)
H20.84900.13760.56800.082*
C30.7231 (2)0.0043 (3)0.4548 (2)0.0868 (7)
H30.73550.07910.40210.104*
C40.6378 (3)0.1410 (3)0.4322 (2)0.0881 (6)
H40.59610.16330.36300.106*
C50.6143 (2)0.2526 (2)0.51121 (16)0.0660 (4)
H50.55640.35000.49570.079*
C60.67764 (16)0.21950 (16)0.61527 (13)0.0471 (3)
C70.65159 (14)0.32946 (14)0.70800 (12)0.0408 (3)
C80.70310 (13)0.27662 (13)0.82869 (12)0.0364 (3)
C90.86085 (15)0.14797 (14)0.78248 (14)0.0441 (3)
H9A0.94230.18210.71190.053*
H9B0.89860.11030.85750.053*
C100.57037 (15)0.22930 (13)0.94184 (12)0.0402 (3)
C110.5050 (2)0.09585 (19)1.14593 (15)0.0660 (4)
H11A0.44360.17731.20680.099*
H11B0.55730.01161.19170.099*
H11C0.43430.07071.11530.099*
C120.70663 (14)0.42463 (13)0.86467 (12)0.0385 (3)
H120.66160.43540.96290.046*
C130.87197 (14)0.44101 (14)0.81075 (13)0.0410 (3)
C140.92427 (19)0.51937 (18)0.69297 (15)0.0559 (4)
H140.85570.56570.64470.067*
C151.0783 (2)0.5294 (2)0.64626 (18)0.0781 (5)
H151.11320.58170.56670.094*
C161.1786 (2)0.4619 (3)0.7180 (2)0.0845 (6)
H161.28150.46920.68660.101*
C171.12966 (19)0.3833 (2)0.8361 (2)0.0708 (5)
H171.19900.33780.88370.085*
C180.97535 (16)0.37288 (15)0.88296 (15)0.0493 (3)
C191.0138 (3)0.2223 (2)1.0745 (2)0.0877 (6)
H19A1.10420.14421.02190.132*
H19B0.95310.18071.15510.132*
H19C1.05170.29091.09830.132*
N10.59522 (14)0.47046 (13)0.69528 (12)0.0500 (3)
O10.83574 (12)0.03193 (10)0.73258 (10)0.0533 (3)
O20.59926 (11)0.53548 (10)0.80421 (10)0.0503 (3)
O30.43272 (12)0.27371 (14)0.94996 (11)0.0638 (3)
O40.62574 (12)0.13826 (11)1.03084 (10)0.0543 (3)
O50.91320 (14)0.29842 (12)0.99727 (11)0.0631 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0439 (7)0.0600 (8)0.0443 (7)0.0261 (6)0.0036 (6)0.0086 (6)
C20.0591 (9)0.0735 (10)0.0691 (10)0.0301 (8)0.0017 (8)0.0262 (8)
C30.0716 (12)0.1236 (18)0.0755 (12)0.0442 (13)0.0075 (10)0.0495 (12)
C40.0765 (13)0.137 (2)0.0656 (11)0.0388 (13)0.0267 (10)0.0296 (12)
C50.0616 (10)0.0929 (12)0.0524 (8)0.0310 (9)0.0235 (7)0.0032 (8)
C60.0423 (7)0.0615 (8)0.0412 (6)0.0252 (6)0.0105 (5)0.0016 (6)
C70.0331 (6)0.0483 (7)0.0433 (6)0.0173 (5)0.0140 (5)0.0041 (5)
C80.0310 (6)0.0381 (6)0.0404 (6)0.0124 (5)0.0122 (5)0.0005 (5)
C90.0371 (6)0.0408 (6)0.0520 (7)0.0090 (5)0.0155 (5)0.0037 (5)
C100.0419 (7)0.0419 (6)0.0416 (6)0.0195 (5)0.0139 (5)0.0018 (5)
C110.0900 (12)0.0707 (10)0.0456 (8)0.0495 (9)0.0156 (8)0.0110 (7)
C120.0333 (6)0.0377 (6)0.0448 (6)0.0116 (5)0.0146 (5)0.0010 (5)
C130.0363 (6)0.0436 (6)0.0462 (6)0.0167 (5)0.0138 (5)0.0025 (5)
C140.0581 (9)0.0685 (9)0.0499 (7)0.0350 (7)0.0172 (7)0.0043 (7)
C150.0699 (11)0.1101 (15)0.0617 (10)0.0595 (11)0.0034 (9)0.0006 (9)
C160.0441 (9)0.1152 (16)0.0962 (14)0.0423 (10)0.0056 (9)0.0179 (12)
C170.0447 (8)0.0802 (11)0.0975 (13)0.0169 (8)0.0346 (9)0.0135 (10)
C180.0436 (7)0.0501 (7)0.0605 (8)0.0152 (6)0.0242 (6)0.0034 (6)
C190.1082 (16)0.0698 (11)0.0944 (14)0.0083 (11)0.0694 (13)0.0104 (10)
N10.0463 (6)0.0503 (6)0.0596 (7)0.0170 (5)0.0276 (5)0.0080 (5)
O10.0579 (6)0.0407 (5)0.0587 (6)0.0131 (4)0.0190 (5)0.0054 (4)
O20.0451 (5)0.0388 (5)0.0712 (6)0.0086 (4)0.0302 (5)0.0000 (4)
O30.0389 (5)0.0922 (8)0.0632 (6)0.0304 (5)0.0169 (5)0.0098 (6)
O40.0582 (6)0.0577 (6)0.0492 (5)0.0273 (5)0.0190 (5)0.0140 (4)
O50.0719 (7)0.0639 (6)0.0685 (7)0.0266 (6)0.0434 (6)0.0168 (5)
Geometric parameters (Å, º) top
C1—O11.3718 (17)C11—H11A0.9600
C1—C21.394 (2)C11—H11B0.9600
C1—C61.395 (2)C11—H11C0.9600
C2—C31.379 (3)C12—O21.4521 (15)
C2—H20.9300C12—C131.5102 (16)
C3—C41.382 (3)C12—H120.9800
C3—H30.9300C13—C141.3829 (19)
C4—C51.372 (3)C13—C181.3959 (18)
C4—H40.9300C14—C151.388 (2)
C5—C61.402 (2)C14—H140.9300
C5—H50.9300C15—C161.370 (3)
C6—C71.4544 (19)C15—H150.9300
C7—N11.2775 (17)C16—C171.380 (3)
C7—C81.5053 (16)C16—H160.9300
C8—C91.5237 (16)C17—C181.392 (2)
C8—C101.5327 (16)C17—H170.9300
C8—C121.5476 (16)C18—O51.3604 (18)
C9—O11.4352 (16)C19—O51.4296 (19)
C9—H9A0.9700C19—H19A0.9600
C9—H9B0.9700C19—H19B0.9600
C10—O31.1918 (15)C19—H19C0.9600
C10—O41.3225 (15)N1—O21.4229 (15)
C11—O41.4531 (17)
O1—C1—C2116.64 (14)O4—C11—H11C109.5
O1—C1—C6122.61 (12)H11A—C11—H11C109.5
C2—C1—C6120.73 (15)H11B—C11—H11C109.5
C3—C2—C1118.83 (18)O2—C12—C13110.92 (10)
C3—C2—H2120.6O2—C12—C8102.91 (9)
C1—C2—H2120.6C13—C12—C8114.29 (10)
C2—C3—C4120.97 (17)O2—C12—H12109.5
C2—C3—H3119.5C13—C12—H12109.5
C4—C3—H3119.5C8—C12—H12109.5
C5—C4—C3120.49 (18)C14—C13—C18119.30 (12)
C5—C4—H4119.8C14—C13—C12122.56 (12)
C3—C4—H4119.8C18—C13—C12118.14 (11)
C4—C5—C6119.91 (19)C13—C14—C15120.48 (16)
C4—C5—H5120.0C13—C14—H14119.8
C6—C5—H5120.0C15—C14—H14119.8
C1—C6—C5119.02 (14)C16—C15—C14119.62 (16)
C1—C6—C7117.43 (12)C16—C15—H15120.2
C5—C6—C7123.53 (14)C14—C15—H15120.2
N1—C7—C6126.69 (12)C15—C16—C17121.24 (15)
N1—C7—C8114.75 (11)C15—C16—H16119.4
C6—C7—C8118.48 (11)C17—C16—H16119.4
C7—C8—C9106.98 (10)C16—C17—C18119.23 (16)
C7—C8—C10109.18 (9)C16—C17—H17120.4
C9—C8—C10112.00 (10)C18—C17—H17120.4
C7—C8—C1299.03 (9)O5—C18—C17124.89 (14)
C9—C8—C12118.65 (10)O5—C18—C13114.98 (12)
C10—C8—C12109.87 (9)C17—C18—C13120.13 (15)
O1—C9—C8109.50 (10)O5—C19—H19A109.5
O1—C9—H9A109.8O5—C19—H19B109.5
C8—C9—H9A109.8H19A—C19—H19B109.5
O1—C9—H9B109.8O5—C19—H19C109.5
C8—C9—H9B109.8H19A—C19—H19C109.5
H9A—C9—H9B108.2H19B—C19—H19C109.5
O3—C10—O4124.43 (12)C7—N1—O2107.98 (10)
O3—C10—C8123.42 (12)C1—O1—C9116.02 (10)
O4—C10—C8112.11 (10)N1—O2—C12108.84 (9)
O4—C11—H11A109.5C10—O4—C11115.35 (12)
O4—C11—H11B109.5C18—O5—C19118.13 (14)
H11A—C11—H11B109.5
O1—C1—C2—C3179.39 (14)C10—C8—C12—O291.49 (11)
C6—C1—C2—C31.0 (2)C7—C8—C12—C1397.56 (11)
C1—C2—C3—C41.1 (3)C9—C8—C12—C1317.51 (15)
C2—C3—C4—C51.8 (3)C10—C8—C12—C13148.16 (10)
C3—C4—C5—C60.3 (3)O2—C12—C13—C1417.90 (17)
O1—C1—C6—C5179.24 (12)C8—C12—C13—C1497.88 (15)
C2—C1—C6—C52.5 (2)O2—C12—C13—C18162.62 (11)
O1—C1—C6—C72.07 (18)C8—C12—C13—C1881.60 (14)
C2—C1—C6—C7176.20 (12)C18—C13—C14—C150.5 (2)
C4—C5—C6—C11.8 (2)C12—C13—C14—C15178.98 (14)
C4—C5—C6—C7176.77 (15)C13—C14—C15—C160.4 (3)
C1—C6—C7—N1168.16 (12)C14—C15—C16—C170.3 (3)
C5—C6—C7—N113.2 (2)C15—C16—C17—C180.1 (3)
C1—C6—C7—C88.22 (17)C16—C17—C18—O5179.75 (16)
C5—C6—C7—C8170.40 (12)C16—C17—C18—C130.2 (2)
N1—C7—C8—C9138.72 (11)C14—C13—C18—O5179.97 (12)
C6—C7—C8—C938.09 (14)C12—C13—C18—O50.47 (18)
N1—C7—C8—C1099.88 (12)C14—C13—C18—C170.4 (2)
C6—C7—C8—C1083.31 (13)C12—C13—C18—C17179.12 (13)
N1—C7—C8—C1214.94 (13)C6—C7—N1—O2176.52 (11)
C6—C7—C8—C12161.87 (10)C8—C7—N1—O20.02 (14)
C7—C8—C9—O159.44 (13)C2—C1—O1—C9159.71 (12)
C10—C8—C9—O160.16 (13)C6—C1—O1—C921.95 (17)
C12—C8—C9—O1170.16 (10)C8—C9—O1—C153.68 (14)
C7—C8—C10—O323.21 (17)C7—N1—O2—C1216.69 (13)
C9—C8—C10—O3141.51 (13)C13—C12—O2—N197.46 (11)
C12—C8—C10—O384.40 (15)C8—C12—O2—N125.18 (12)
C7—C8—C10—O4158.97 (10)O3—C10—O4—C111.54 (19)
C9—C8—C10—O440.67 (14)C8—C10—O4—C11176.26 (11)
C12—C8—C10—O493.43 (12)C17—C18—O5—C191.3 (2)
C7—C8—C12—O222.79 (11)C13—C18—O5—C19178.27 (14)
C9—C8—C12—O2137.86 (11)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C17—H17···O3i0.932.423.3084 (19)159
Symmetry code: (i) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C17—H17···O3i0.932.423.3084 (19)159
Symmetry code: (i) x+1, y, z.
Acknowledgements top

The authors acknowledge the Technology Business Incubator (TBI), CAS in Crystallography, University of Madras, Chennai 600 025, India, for the data collection.

references
References top

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