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Acta Crystallogr Sect E Struct Rep Online. 2008 January 1; 64(Pt 1): o342.
Published online 2007 December 21. doi:  10.1107/S1600536807064938
PMCID: PMC2915383

3-[3-(4-Bromo­phen­yl)-1-phenyl-1H-pyrazol-4-yl]-5-eth­oxy-2-phenyl­isoxazolidine

Abstract

In the title compound, C26H24BrN3O2, the isoxazolidine ring adopts an envelope conformation, the ring N atom deviating from the mean plane of the other four atoms by an angle of 0.286°. The orientation of the phenyl ring is +sp and the bromophenyl ring is +sc relative to the attached pyrazole ring; the dihedral angles between the least-squares planes of the pyrazole and the attached phenyl and bromophenyl rings are 21.8 (3) and 41.8 (3)°.

Related literature

For related literature, see: Allen et al. (1987 [triangle]); Gayathri et al. (2007 [triangle]); Frederickson (1997 [triangle]); Gothelf et al. (2002 [triangle]); Huisgen (1984 [triangle]); Kumar et al. (2003 [triangle]).

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Object name is e-64-0o342-scheme1.jpg

Experimental

Crystal data

  • C26H24BrN3O2
  • M r = 490.39
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-0o342-efi1.jpg
  • a = 27.7493 (6) Å
  • b = 7.4254 (2) Å
  • c = 24.5230 (5) Å
  • β = 114.516 (1)°
  • V = 4597.41 (18) Å3
  • Z = 8
  • Mo Kα radiation
  • μ = 1.82 mm−1
  • T = 293 (2) K
  • 0.26 × 0.23 × 0.22 mm

Data collection

  • Bruker Kappa APEXII diffractometer
  • Absorption correction: multi-scan (SAINT; Bruker, 1999 [triangle]) T min = 0.650, T max = 0.691
  • 23867 measured reflections
  • 4982 independent reflections
  • 3038 reflections with I > 2σ(I)
  • R int = 0.041

Refinement

  • R[F 2 > 2σ(F 2)] = 0.036
  • wR(F 2) = 0.096
  • S = 1.00
  • 4982 reflections
  • 289 parameters
  • H-atom parameters constrained
  • Δρmax = 0.37 e Å−3
  • Δρmin = −0.49 e Å−3

Data collection: APEX2 (Bruker, 2004 [triangle]); cell refinement: SAINT (Bruker, 1999 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 [triangle]); molecular graphics: PLATON (Spek, 2003 [triangle]); software used to prepare material for publication: SHELXL97 and PARST97 (Nardelli, 1995 [triangle]).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807064938/lw2049sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807064938/lw2049Isup2.hkl

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

Acknowledgments

SE thanks the Council of Scientific and Industrial Research (CSIR), New Delhi, for providing financial assistance as a Senior Research Fellowship (SRF).

supplementary crystallographic information

Comment

The 1,3-dipolar cycloadditionof nitrones to alkenes provides a straight forward route to isoxazolidines(Frederickson, 1997, Gothelf et al., 2002). The nitrone cycloadducts are attractive intermediates for the synthesis of several class of natural products and biologically active compounds such as b-aminoacids and alkaloids.(Huisgen, 1984).The pyrazole unit is the core structure in a number of natural products. Many pyrazole derivatives are known to exhibit a wide range of biological properties such as anti-hyperglycemic, analgesic, anti-inflammatory, anti-pyretic, anti-bacterial, hypoglycemic, sedative, hypnotic activity, and anticoagulant activity. Particularly, arylpyrazoles are widely used in medicinal and pesticidal chemistry. Recently some arylpyrazoles were reported to display non-nucleoside HIV-1 reverse transcriptase inhibitory activity (Kumar et al., 2003).

The isoxazolidine ring adopts envelope conformation with N as the flap, atom N7 deviates from the mean plane with a maximum deviation of 0.286 (2)°. The ethoxy group attached to the isoxazolidine adopts an extended conformation. The bond lengths and bond angles are comparable with literature values (Allen et al.,1987).The dihedral angle between the LSQ planes of pyrazole and phenyl and bromo phenyl ring is 21.8 (3)° and 41.8 (3)°, which is lower than the reported value due to the simple substitution of a bromine to the phenyl ring (Gayathri et al.,2007). The phenyl ring is equatorially substituted to the isoxazolidine ring and slightly twisted due to the steric hinderance with the bromophenyl ring and the ethoxy group is substituted axailly to the isoxazolidine ring. The molecule iss stabilized by intra molecular C—H···O hydrogen bonds in the unit cell.

Experimental

A solution of pyrazole nitrone (0.5 mmol) and ethyl vinyl ether (5 mmol) was refluxed in dry toluene (10 mL) at 60°C until the completion of the reaction as evidenced by thin-layer chromatography. The solvent was evaporated under reduced pressure. The crude was purified by column chromatography using ethyl acetate-petroleum ether (3:97) as eluent, to afford the pure isoxazolidine (68%) as a white solid. Single crystals were obtained by crystallization from petroleum ether and ethyl acetate mixture.

Figures

Fig. 1.
The ORTEP diagram of the title compound with 30% probability displacement ellipsoids.
Fig. 2.
Packing of the molecules viewed down c axis.

Crystal data

C26H24BrN3O2F000 = 2016
Mr = 490.39Dx = 1.417 Mg m3
Monoclinic, C2/cMo Kα radiation λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 4982 reflections
a = 27.7493 (6) Åθ = 2.9–27.0º
b = 7.4254 (2) ŵ = 1.82 mm1
c = 24.5230 (5) ÅT = 293 (2) K
β = 114.516 (1)ºCubic, yellow
V = 4597.41 (18) Å30.26 × 0.23 × 0.22 mm
Z = 8

Data collection

Bruker Kappa APEXII diffractometer4982 independent reflections
Radiation source: fine-focus sealed tube3038 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.041
T = 293(2) Kθmax = 27.0º
ω and [var phi] scansθmin = 2.9º
Absorption correction: multi-scan(SAINT; Bruker, 1999)h = −35→35
Tmin = 0.650, Tmax = 0.691k = −9→9
23867 measured reflectionsl = −31→31

Refinement

Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.036  w = 1/[σ2(Fo2) + (0.0394P)2 + 2.7695P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.096(Δ/σ)max = 0.004
S = 1.00Δρmax = 0.37 e Å3
4982 reflectionsΔρmin = −0.49 e Å3
289 parametersExtinction correction: SHELXL
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0028 (11)
Secondary atom site location: difference Fourier map

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 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)

xyzUiso*/Ueq
Br11.015166 (12)0.61394 (5)0.097949 (17)0.09166 (16)
N10.76772 (7)0.4888 (2)0.08475 (8)0.0420 (4)
N20.72795 (7)0.4783 (2)0.10324 (8)0.0412 (4)
C30.74697 (9)0.4845 (3)0.16353 (10)0.0436 (5)
H30.72680.47940.18570.052*
C40.80068 (9)0.4996 (3)0.18641 (9)0.0388 (5)
C50.81190 (9)0.5021 (3)0.13506 (9)0.0381 (5)
C110.67491 (9)0.4517 (3)0.06083 (10)0.0419 (5)
C160.66488 (10)0.3876 (3)0.00433 (11)0.0531 (6)
H70.69260.3660−0.00670.064*
C150.61347 (11)0.3559 (3)−0.03539 (13)0.0661 (7)
H80.60660.3131−0.07360.079*
C140.57219 (11)0.3861 (4)−0.01980 (14)0.0699 (8)
H90.53760.3615−0.04680.084*
C130.58227 (10)0.4529 (4)0.03587 (14)0.0650 (7)
H100.55430.47490.04650.078*
C120.63349 (10)0.4881 (3)0.07642 (11)0.0524 (6)
H110.64000.53590.11390.063*
C60.83710 (9)0.5082 (3)0.25106 (9)0.0400 (5)
H60.87320.53370.25550.048*
N70.83638 (7)0.3344 (2)0.28223 (7)0.0396 (4)
O80.86261 (6)0.3879 (2)0.34526 (6)0.0474 (4)
C90.83812 (9)0.5532 (3)0.34867 (10)0.0446 (5)
H9A0.86370.62990.37980.054*
C100.82134 (10)0.6428 (3)0.28798 (10)0.0497 (6)
H10A0.83960.75650.29160.060*
H10B0.78340.66420.26980.060*
C170.86907 (9)0.1977 (3)0.27316 (10)0.0412 (5)
C220.84549 (10)0.0922 (3)0.22259 (11)0.0521 (6)
H180.80980.10670.19760.062*
C210.87546 (12)−0.0354 (3)0.20937 (13)0.0642 (7)
H190.8600−0.10390.17460.077*
C200.92747 (13)−0.0614 (4)0.24692 (15)0.0718 (8)
H200.9473−0.14800.23800.086*
C190.95026 (11)0.0402 (4)0.29764 (14)0.0718 (8)
H210.98560.02170.32340.086*
C180.92128 (10)0.1703 (3)0.31106 (12)0.0573 (6)
H220.93710.23910.34570.069*
O230.79337 (6)0.5295 (2)0.35987 (6)0.0468 (4)
C240.80487 (10)0.4624 (3)0.41873 (10)0.0504 (6)
H24A0.83190.53580.44860.060*
H24B0.81770.33950.42260.060*
C250.75456 (11)0.4695 (4)0.42755 (12)0.0703 (8)
H25A0.76100.42490.46670.106*
H25B0.72810.39640.39770.106*
H25C0.74230.59170.42380.106*
C260.86227 (9)0.5288 (3)0.12921 (9)0.0387 (5)
C310.86189 (9)0.6344 (3)0.08219 (10)0.0456 (5)
H270.83050.68880.05640.055*
C300.90731 (10)0.6599 (3)0.07315 (11)0.0522 (6)
H280.90650.72910.04120.063*
C290.95350 (9)0.5817 (3)0.11189 (11)0.0513 (6)
C280.95552 (10)0.4791 (3)0.15916 (11)0.0544 (6)
H300.98730.42820.18540.065*
C270.90973 (9)0.4523 (3)0.16740 (10)0.0463 (6)
H310.91080.38150.19920.056*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.0616 (2)0.1079 (3)0.1308 (3)0.00190 (17)0.0650 (2)0.0236 (2)
N10.0463 (11)0.0463 (10)0.0442 (11)−0.0036 (9)0.0296 (10)−0.0001 (8)
N20.0440 (11)0.0436 (10)0.0436 (11)−0.0031 (8)0.0258 (9)0.0021 (8)
C30.0515 (14)0.0448 (12)0.0477 (14)−0.0017 (11)0.0339 (12)0.0042 (10)
C40.0502 (13)0.0355 (11)0.0404 (13)0.0000 (10)0.0285 (11)0.0015 (9)
C50.0443 (13)0.0354 (11)0.0412 (13)0.0000 (10)0.0244 (11)−0.0008 (9)
C110.0444 (13)0.0365 (11)0.0470 (14)−0.0043 (10)0.0211 (11)0.0043 (10)
C160.0518 (15)0.0544 (14)0.0553 (16)−0.0006 (12)0.0246 (13)−0.0019 (12)
C150.0646 (18)0.0661 (17)0.0582 (17)−0.0037 (14)0.0160 (15)−0.0105 (13)
C140.0498 (16)0.0674 (17)0.080 (2)−0.0050 (14)0.0147 (15)0.0006 (15)
C130.0474 (16)0.0686 (17)0.085 (2)0.0019 (13)0.0329 (16)0.0117 (15)
C120.0518 (15)0.0547 (14)0.0589 (15)−0.0013 (12)0.0311 (13)0.0020 (12)
C60.0496 (13)0.0389 (11)0.0418 (13)−0.0025 (10)0.0291 (11)−0.0011 (10)
N70.0501 (11)0.0415 (9)0.0329 (10)0.0028 (8)0.0231 (9)0.0001 (8)
O80.0559 (10)0.0548 (9)0.0356 (9)0.0104 (8)0.0229 (8)−0.0017 (7)
C90.0498 (14)0.0482 (13)0.0425 (13)−0.0005 (11)0.0258 (11)−0.0080 (10)
C100.0710 (16)0.0422 (12)0.0487 (14)0.0039 (11)0.0377 (13)0.0000 (10)
C170.0507 (14)0.0369 (11)0.0472 (13)0.0000 (10)0.0314 (12)0.0036 (10)
C220.0604 (15)0.0440 (13)0.0570 (16)−0.0029 (11)0.0296 (13)−0.0065 (11)
C210.081 (2)0.0482 (14)0.0740 (19)−0.0064 (14)0.0422 (17)−0.0176 (13)
C200.080 (2)0.0531 (16)0.100 (2)0.0077 (15)0.055 (2)−0.0111 (16)
C190.0570 (17)0.0723 (18)0.086 (2)0.0146 (15)0.0292 (16)−0.0078 (17)
C180.0571 (16)0.0554 (14)0.0623 (17)0.0067 (12)0.0276 (14)−0.0070 (12)
O230.0522 (10)0.0572 (9)0.0387 (9)0.0068 (8)0.0266 (8)0.0029 (7)
C240.0676 (16)0.0511 (13)0.0409 (13)0.0092 (12)0.0310 (12)0.0044 (11)
C250.080 (2)0.0892 (19)0.0590 (17)0.0074 (16)0.0456 (16)0.0151 (15)
C260.0464 (13)0.0383 (11)0.0402 (12)−0.0014 (10)0.0268 (11)−0.0049 (10)
C310.0464 (13)0.0485 (13)0.0481 (14)0.0030 (11)0.0259 (11)0.0058 (11)
C300.0579 (16)0.0517 (14)0.0611 (16)−0.0013 (12)0.0388 (14)0.0091 (12)
C290.0469 (14)0.0543 (14)0.0665 (16)−0.0033 (12)0.0372 (13)−0.0011 (12)
C280.0444 (14)0.0663 (16)0.0545 (16)0.0064 (12)0.0224 (13)0.0017 (13)
C270.0536 (15)0.0515 (13)0.0419 (13)0.0042 (11)0.0277 (12)0.0037 (10)

Geometric parameters (Å, °)

Br1—C291.894 (2)C10—H10A0.9700
N1—C51.334 (3)C10—H10B0.9700
N1—N21.358 (2)C17—C181.374 (3)
N2—C31.349 (3)C17—C221.381 (3)
N2—C111.420 (3)C22—C211.385 (3)
C3—C41.362 (3)C22—H180.9300
C3—H30.9300C21—C201.366 (4)
C4—C51.417 (3)C21—H190.9300
C4—C61.486 (3)C20—C191.365 (4)
C5—C261.476 (3)C20—H200.9300
C11—C161.380 (3)C19—C181.381 (3)
C11—C121.380 (3)C19—H210.9300
C16—C151.373 (4)C18—H220.9300
C16—H70.9300O23—C241.432 (2)
C15—C141.369 (4)C24—C251.500 (3)
C15—H80.9300C24—H24A0.9700
C14—C131.368 (4)C24—H24B0.9700
C14—H90.9300C25—H25A0.9600
C13—C121.380 (3)C25—H25B0.9600
C13—H100.9300C25—H25C0.9600
C12—H110.9300C26—C271.382 (3)
C6—N71.504 (3)C26—C311.391 (3)
C6—C101.529 (3)C31—C301.380 (3)
C6—H60.9800C31—H270.9300
N7—C171.439 (3)C30—C291.368 (3)
N7—O81.464 (2)C30—H280.9300
O8—C91.422 (3)C29—C281.369 (3)
C9—O231.390 (2)C28—C271.381 (3)
C9—C101.516 (3)C28—H300.9300
C9—H9A0.9800C27—H310.9300
C5—N1—N2104.94 (16)C6—C10—H10B110.9
C3—N2—N1111.19 (17)H10A—C10—H10B108.9
C3—N2—C11128.51 (17)C18—C17—C22119.8 (2)
N1—N2—C11120.16 (17)C18—C17—N7123.8 (2)
N2—C3—C4108.54 (17)C22—C17—N7116.4 (2)
N2—C3—H3125.7C17—C22—C21119.4 (2)
C4—C3—H3125.7C17—C22—H18120.3
C3—C4—C5103.97 (18)C21—C22—H18120.3
C3—C4—C6125.90 (18)C20—C21—C22120.5 (3)
C5—C4—C6130.13 (19)C20—C21—H19119.7
N1—C5—C4111.36 (18)C22—C21—H19119.7
N1—C5—C26117.65 (17)C19—C20—C21119.8 (2)
C4—C5—C26130.8 (2)C19—C20—H20120.1
C16—C11—C12120.1 (2)C21—C20—H20120.1
C16—C11—N2119.9 (2)C20—C19—C18120.5 (3)
C12—C11—N2119.9 (2)C20—C19—H21119.7
C15—C16—C11119.3 (2)C18—C19—H21119.7
C15—C16—H7120.4C17—C18—C19119.8 (2)
C11—C16—H7120.4C17—C18—H22120.1
C14—C15—C16121.2 (3)C19—C18—H22120.1
C14—C15—H8119.4C9—O23—C24113.54 (17)
C16—C15—H8119.4O23—C24—C25107.5 (2)
C13—C14—C15119.3 (3)O23—C24—H24A110.2
C13—C14—H9120.3C25—C24—H24A110.2
C15—C14—H9120.3O23—C24—H24B110.2
C14—C13—C12120.7 (2)C25—C24—H24B110.2
C14—C13—H10119.6H24A—C24—H24B108.5
C12—C13—H10119.6C24—C25—H25A109.5
C13—C12—C11119.4 (2)C24—C25—H25B109.5
C13—C12—H11120.3H25A—C25—H25B109.5
C11—C12—H11120.3C24—C25—H25C109.5
C4—C6—N7111.02 (16)H25A—C25—H25C109.5
C4—C6—C10115.13 (18)H25B—C25—H25C109.5
N7—C6—C10101.09 (15)C27—C26—C31118.09 (19)
C4—C6—H6109.8C27—C26—C5123.58 (19)
N7—C6—H6109.8C31—C26—C5118.3 (2)
C10—C6—H6109.8C30—C31—C26121.1 (2)
C17—N7—O8106.59 (15)C30—C31—H27119.4
C17—N7—C6112.61 (15)C26—C31—H27119.4
O8—N7—C6101.43 (14)C29—C30—C31119.0 (2)
C9—O8—N7104.82 (14)C29—C30—H28120.5
O23—C9—O8112.99 (18)C31—C30—H28120.5
O23—C9—C10108.29 (19)C30—C29—C28121.4 (2)
O8—C9—C10106.28 (16)C30—C29—Br1118.51 (17)
O23—C9—H9A109.7C28—C29—Br1120.05 (19)
O8—C9—H9A109.7C29—C28—C27119.2 (2)
C10—C9—H9A109.7C29—C28—H30120.4
C9—C10—C6104.34 (17)C27—C28—H30120.4
C9—C10—H10A110.9C28—C27—C26121.1 (2)
C6—C10—H10A110.9C28—C27—H31119.4
C9—C10—H10B110.9C26—C27—H31119.4
C5—N1—N2—C3−0.1 (2)N7—O8—C9—C10−29.9 (2)
C5—N1—N2—C11−176.21 (17)O23—C9—C10—C6−119.66 (19)
N1—N2—C3—C40.0 (2)O8—C9—C10—C62.0 (2)
C11—N2—C3—C4175.68 (19)C4—C6—C10—C9145.05 (18)
N2—C3—C4—C50.1 (2)N7—C6—C10—C925.3 (2)
N2—C3—C4—C6−179.11 (18)O8—N7—C17—C18−18.5 (3)
N2—N1—C5—C40.2 (2)C6—N7—C17—C1891.9 (2)
N2—N1—C5—C26−175.78 (17)O8—N7—C17—C22162.37 (17)
C3—C4—C5—N1−0.2 (2)C6—N7—C17—C22−87.3 (2)
C6—C4—C5—N1178.98 (19)C18—C17—C22—C21−2.7 (3)
C3—C4—C5—C26175.1 (2)N7—C17—C22—C21176.5 (2)
C6—C4—C5—C26−5.7 (4)C17—C22—C21—C202.2 (4)
C3—N2—C11—C16−157.4 (2)C22—C21—C20—C19−0.5 (4)
N1—N2—C11—C1617.9 (3)C21—C20—C19—C18−0.6 (4)
C3—N2—C11—C1221.8 (3)C22—C17—C18—C191.6 (4)
N1—N2—C11—C12−162.82 (19)N7—C17—C18—C19−177.5 (2)
C12—C11—C16—C15−1.8 (3)C20—C19—C18—C170.1 (4)
N2—C11—C16—C15177.5 (2)O8—C9—O23—C2468.5 (2)
C11—C16—C15—C14−0.3 (4)C10—C9—O23—C24−174.05 (17)
C16—C15—C14—C131.5 (4)C9—O23—C24—C25171.8 (2)
C15—C14—C13—C12−0.7 (4)N1—C5—C26—C27−143.2 (2)
C14—C13—C12—C11−1.4 (4)C4—C5—C26—C2741.8 (3)
C16—C11—C12—C132.6 (3)N1—C5—C26—C3135.7 (3)
N2—C11—C12—C13−176.7 (2)C4—C5—C26—C31−139.3 (2)
C3—C4—C6—N765.4 (3)C27—C26—C31—C301.1 (3)
C5—C4—C6—N7−113.6 (2)C5—C26—C31—C30−177.9 (2)
C3—C4—C6—C10−48.7 (3)C26—C31—C30—C29−1.0 (3)
C5—C4—C6—C10132.3 (2)C31—C30—C29—C280.1 (4)
C4—C6—N7—C1780.7 (2)C31—C30—C29—Br1178.75 (17)
C10—C6—N7—C17−156.73 (18)C30—C29—C28—C270.8 (4)
C4—C6—N7—O8−165.78 (15)Br1—C29—C28—C27−177.84 (18)
C10—C6—N7—O8−43.17 (19)C29—C28—C27—C26−0.8 (4)
C17—N7—O8—C9164.37 (15)C31—C26—C27—C28−0.2 (3)
C6—N7—O8—C946.37 (17)C5—C26—C27—C28178.8 (2)
N7—O8—C9—O2388.77 (19)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LW2049).

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