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Acta Crystallogr Sect E Struct Rep Online. 2009 January 1; 65(Pt 1): o27.
Published online 2008 December 6. doi:  10.1107/S1600536808040105
PMCID: PMC2967946

(3S,7aR)-7-Meth­oxy-7a-methyl-3-phenyl-2,3-dihydro­pyrrolo[2,1-b]oxazol-5(7aH)-one

Abstract

In the title chiral butterfly-like bicyclic lactam, C14H15NO3, the phenyl and methyl groups are syn with respect to each other. The dihydro­pyrrrole ring adopts a boat conformation, whereas the oxazole ring has a slightly distorted boat conformation. The packing of mol­ecules in the crystal structure is stabilized by inter­molecular C—H(...)O hydrogen bonds.

Related literature

For reference bond-length data, see: Allen et al. (1987 [triangle]). For the chemistry of tetra­mic acids and methyl tetra­mates, see: Huang & Deng (2004 [triangle]); Huang et al. (2003 [triangle]); Jiang et al. (2009 [triangle]).

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Object name is e-65-00o27-scheme1.jpg

Experimental

Crystal data

  • C14H15NO3
  • M r = 245.27
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-00o27-efi1.jpg
  • a = 7.8238 (10) Å
  • b = 5.9033 (7) Å
  • c = 13.711 (3) Å
  • β = 96.597 (14)°
  • V = 629.05 (16) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 293 (2) K
  • 0.40 × 0.18 × 0.12 mm

Data collection

  • Oxford Diffraction Gemini S Ultra diffractometer
  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008 [triangle]) T min = 0.964, T max = 0.984
  • 3205 measured reflections
  • 1170 independent reflections
  • 691 reflections with I > 2σ(I)
  • R int = 0.067

Refinement

  • R[F 2 > 2σ(F 2)] = 0.045
  • wR(F 2) = 0.076
  • S = 0.89
  • 1170 reflections
  • 163 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.15 e Å−3
  • Δρmin = −0.14 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 [triangle]); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 [triangle]); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808040105/wn2289sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808040105/wn2289Isup2.hkl

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

Acknowledgments

The authors thank the Natural Science Foundation of China (No. 20602028) and Xiamen University Science Foundation (No. XDKJCX20053013) for financial support. We also thank Mr Zan-Bin Wei and Mr Ting-Bin Wen for technical assistance.

supplementary crystallographic information

Comment

The title compound, which was obtained by treating 5-hydroxy-1-((S)-2-hydroxy-1-phenylethyl) -4-methoxy-5-methyl-1H-pyrrol-2(5H)-one and picolinic acid with a catalytic amount of p-TsOH in CH2Cl2 at room temperature, is a key intermediate for the preparation of tetramic acids and methyl tetramates bearing C-5 methyl substituents; this is a key framework in a number of bioactive natural products, such as melophlins and mirabimide E (Huang & Deng, 2004; Huang et al., 2003; Jiang et al., 2009).

An X-ray crystal structure determination of the molecular structure of the title compound was carried out to determine its conformation. In the title chiral butterfly-like bicyclic lactam, C14H15NO3, in which the angle O3—C14—C6 is 112.3 (4)° and C8—N1—C9 is 119.6 (3)°, the phenyl and methyl groups are syn with respect to each other. The dihydropyrrrole ring adopts a boat conformation, whereas in the oxazole ring the conformation is that of a slightly distorted boat. Bond lengths and angles are in agreement with values reported in the literature (Allen et al., 1987). The packing of molecules in the crystal structure is stabilized by intermolecular C—H···O hydrogen bonds.

Experimental

To a cool (-78 °C) solution of (S)-1-(2-hydroxyl-1-phenylethyl) -3-methoxy-1H-pyrrole-2,5-dione(1.0 mmol) in anhydrous THF (10 ml) was added dropwise CH3MgBr (3.0 mmol) in diethyl ether under a nitrogen atmosphere. After stirring at the same temperature for 45 minutes, the reaction was quenched with saturated ammonium chloride (6 ml), and extracted with EtOAc (4 × 10 ml). The combined extracts were washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by flash chromatography and yielded a mixture of diastereomers. To the mixture of diastereomers (0.51 mmol) in CH2Cl2 (10 ml) was added p-toluenesulfonic acid monohydrate (0.16 mmol.). After stirring for 30 minutes at room temperature, the mixture was quenched with saturated NaHCO3 solution. The organic layer was separated and the aqueous phase was extracted with CH2Cl2 (3 × 5 ml). The combined organic layers were washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by flash chromatography to yield the title compound. Single crystals were obtained by slow evaporation of a petroleum ether / ethyl acetate solution.

Refinement

The hydrogen atoms were positioned geometrically, with C—H = 0.93, 0.98, 0.97 and 0.96 Å for phenyl, methine, methylene and methyl H atoms, respectively, and were included in the refinement in the riding model approximation. The displacement parameters of methyl H atoms were set to 1.5Ueq(C), while those of other H atoms were set to 1.2Ueq(C). In the absence of significant anomalous scattering effects, Friedel pairs were merged.

Figures

Fig. 1.
The molecular structure of the title compound with the atom-labelling scheme, showing 50% probability displacement ellipsoids. H atoms are drawn as spheres of arbitrary radius.
Fig. 2.
The packing of the molecules, viewed down the b axis. C—H···O hydrogen bond interactions are shown as dashed lines.

Crystal data

C14H15NO3F(000) = 260
Mr = 245.27Dx = 1.295 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 672 reflections
a = 7.8238 (10) Åθ = 2.9–32.6°
b = 5.9033 (7) ŵ = 0.09 mm1
c = 13.711 (3) ÅT = 293 K
β = 96.597 (14)°Needle, colourless
V = 629.05 (16) Å30.40 × 0.18 × 0.12 mm
Z = 2

Data collection

Oxford Diffraction Gemini S Ultra diffractometer1170 independent reflections
Radiation source: fine-focus sealed tube691 reflections with I > 2σ(I)
graphiteRint = 0.067
[var phi] and ω scansθmax = 25.0°, θmin = 2.9°
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008)h = −9→9
Tmin = 0.964, Tmax = 0.984k = −4→7
3205 measured reflectionsl = −16→14

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.076H-atom parameters constrained
S = 0.89w = 1/[σ2(Fo2) + (0.0229P)2] where P = (Fo2 + 2Fc2)/3
1170 reflections(Δ/σ)max = 0.016
163 parametersΔρmax = 0.16 e Å3
1 restraintΔρmin = −0.14 e Å3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
N10.1601 (4)0.4015 (5)0.7374 (3)0.0243 (9)
O2−0.1216 (3)0.4978 (5)0.6847 (3)0.0474 (10)
C30.1854 (5)0.2927 (6)0.9142 (4)0.0283 (12)
O10.3713 (4)0.3770 (5)0.5217 (3)0.0460 (9)
C50.2722 (5)0.4920 (7)0.9416 (4)0.0340 (12)
H5A0.29520.59460.89340.041*
C60.2535 (5)0.4025 (7)0.5833 (4)0.0323 (11)
C70.1517 (5)0.1443 (7)0.9894 (4)0.0340 (13)
H7A0.09330.00950.97400.041*
C80.1279 (5)0.2310 (7)0.8097 (4)0.0309 (12)
H8A0.00440.19770.80300.037*
C90.0262 (5)0.4666 (6)0.6652 (4)0.0310 (11)
C100.2041 (5)0.1961 (8)1.0856 (5)0.0416 (13)
H10A0.18070.09591.13470.050*
C110.3251 (6)0.5415 (8)1.0386 (4)0.0437 (14)
H11A0.38420.67531.05510.052*
O30.3124 (4)0.0915 (5)0.6977 (3)0.0601 (12)
C130.2908 (5)0.3940 (8)1.1107 (4)0.0418 (13)
H13A0.32590.42721.17620.050*
C140.3068 (5)0.3310 (7)0.6872 (4)0.0339 (12)
C150.4755 (5)0.4379 (9)0.7300 (4)0.0503 (14)
H15A0.50330.38850.79660.075*
H15B0.46450.59980.72840.075*
H15C0.56540.39290.69190.075*
C160.0944 (5)0.4851 (7)0.5732 (4)0.0386 (13)
H16A0.03700.54500.51580.046*
C170.3234 (7)0.4610 (10)0.4231 (4)0.0636 (16)
H17A0.41600.43520.38420.095*
H17B0.30010.62040.42550.095*
H17C0.22230.38300.39420.095*
C190.2233 (7)0.0254 (7)0.7733 (5)0.0562 (17)
H19A0.3023−0.03550.82660.067*
H19B0.1414−0.09210.75090.067*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0233 (17)0.0272 (18)0.022 (3)0.0013 (15)0.0014 (17)0.0048 (18)
O20.0300 (16)0.069 (2)0.043 (3)0.0111 (17)0.0055 (16)0.0099 (19)
C30.026 (2)0.026 (3)0.034 (4)0.0031 (18)0.005 (2)0.002 (2)
O10.0494 (19)0.0528 (19)0.039 (3)−0.0044 (17)0.0195 (19)−0.003 (2)
C50.042 (2)0.023 (2)0.037 (4)−0.001 (2)0.002 (2)−0.003 (3)
C60.036 (3)0.029 (2)0.033 (3)−0.012 (2)0.007 (2)−0.005 (2)
C70.027 (2)0.029 (3)0.046 (4)−0.0049 (18)0.004 (3)−0.001 (3)
C80.034 (2)0.025 (2)0.033 (4)−0.011 (2)0.001 (2)−0.003 (2)
C90.029 (2)0.030 (2)0.034 (3)−0.002 (2)0.004 (2)0.000 (2)
C100.035 (3)0.052 (3)0.036 (4)0.003 (3)−0.001 (3)0.012 (3)
C110.054 (3)0.036 (3)0.039 (4)−0.005 (2)−0.008 (3)−0.004 (3)
O30.068 (2)0.035 (2)0.086 (4)0.0224 (16)0.047 (2)0.020 (2)
C130.041 (3)0.058 (3)0.023 (3)0.013 (3)−0.009 (2)0.004 (3)
C140.029 (2)0.030 (3)0.044 (4)0.010 (2)0.011 (2)0.006 (2)
C150.030 (2)0.078 (4)0.043 (4)−0.004 (3)0.003 (2)0.004 (3)
C160.030 (2)0.042 (3)0.041 (4)−0.001 (2)−0.005 (2)0.007 (3)
C170.079 (4)0.074 (4)0.040 (4)−0.025 (3)0.018 (3)−0.004 (4)
C190.082 (4)0.032 (3)0.059 (5)−0.006 (3)0.024 (4)−0.003 (3)

Geometric parameters (Å, °)

N1—C91.410 (5)C10—C131.374 (7)
N1—C81.455 (5)C10—H10A0.9300
N1—C141.465 (5)C11—C131.366 (7)
O2—C91.230 (4)C11—H11A0.9300
C3—C51.389 (5)O3—C191.371 (6)
C3—C71.402 (6)O3—C141.421 (5)
C3—C81.497 (7)C13—H13A0.9300
O1—C61.329 (5)C14—C151.519 (6)
O1—C171.448 (7)C15—H15A0.9600
C5—C111.378 (7)C15—H15B0.9600
C5—H5A0.9300C15—H15C0.9600
C6—C161.329 (5)C16—H16A0.9300
C6—C141.498 (7)C17—H17A0.9600
C7—C101.369 (7)C17—H17B0.9600
C7—H7A0.9300C17—H17C0.9600
C8—C191.538 (6)C19—H19A0.9700
C8—H8A0.9800C19—H19B0.9700
C9—C161.429 (6)
C9—N1—C8119.6 (3)C19—O3—C14110.3 (4)
C9—N1—C14107.9 (4)C11—C13—C10119.5 (5)
C8—N1—C14109.3 (3)C11—C13—H13A120.2
C5—C3—C7117.2 (5)C10—C13—H13A120.2
C5—C3—C8123.4 (4)O3—C14—N1104.6 (3)
C7—C3—C8119.5 (4)O3—C14—C6112.3 (4)
C6—O1—C17115.5 (4)N1—C14—C6102.6 (3)
C11—C5—C3121.7 (5)O3—C14—C15111.0 (4)
C11—C5—H5A119.2N1—C14—C15113.2 (4)
C3—C5—H5A119.2C6—C14—C15112.6 (4)
O1—C6—C16133.2 (5)C14—C15—H15A109.5
O1—C6—C14115.8 (4)C14—C15—H15B109.5
C16—C6—C14111.0 (4)H15A—C15—H15B109.5
C10—C7—C3120.6 (4)C14—C15—H15C109.5
C10—C7—H7A119.7H15A—C15—H15C109.5
C3—C7—H7A119.7H15B—C15—H15C109.5
N1—C8—C3115.3 (3)C6—C16—C9108.7 (5)
N1—C8—C19101.3 (4)C6—C16—H16A125.7
C3—C8—C19113.5 (4)C9—C16—H16A125.7
N1—C8—H8A108.8O1—C17—H17A109.5
C3—C8—H8A108.8O1—C17—H17B109.5
C19—C8—H8A108.8H17A—C17—H17B109.5
O2—C9—N1122.0 (4)O1—C17—H17C109.5
O2—C9—C16129.5 (5)H17A—C17—H17C109.5
N1—C9—C16108.5 (3)H17B—C17—H17C109.5
C7—C10—C13121.0 (5)O3—C19—C8109.2 (4)
C7—C10—H10A119.5O3—C19—H19A109.8
C13—C10—H10A119.5C8—C19—H19A109.8
C13—C11—C5120.0 (5)O3—C19—H19B109.8
C13—C11—H11A120.0C8—C19—H19B109.8
C5—C11—H11A120.0H19A—C19—H19B108.3
C7—C3—C5—C110.7 (5)C19—O3—C14—N1−19.4 (6)
C8—C3—C5—C11−179.1 (4)C19—O3—C14—C6−129.9 (5)
C17—O1—C6—C162.4 (7)C19—O3—C14—C15103.0 (5)
C17—O1—C6—C14−175.9 (4)C9—N1—C14—O3−107.5 (4)
C5—C3—C7—C10−0.3 (6)C8—N1—C14—O324.0 (5)
C8—C3—C7—C10179.5 (4)C9—N1—C14—C69.9 (4)
C9—N1—C8—C3−130.6 (4)C8—N1—C14—C6141.4 (3)
C14—N1—C8—C3104.4 (4)C9—N1—C14—C15131.5 (4)
C9—N1—C8—C19106.3 (4)C8—N1—C14—C15−97.0 (4)
C14—N1—C8—C19−18.6 (5)O1—C6—C14—O3−74.1 (5)
C5—C3—C8—N1−3.5 (6)C16—C6—C14—O3107.3 (4)
C7—C3—C8—N1176.7 (3)O1—C6—C14—N1174.2 (3)
C5—C3—C8—C19112.8 (4)C16—C6—C14—N1−4.4 (5)
C7—C3—C8—C19−67.0 (5)O1—C6—C14—C1552.1 (5)
C8—N1—C9—O242.2 (6)C16—C6—C14—C15−126.5 (4)
C14—N1—C9—O2167.8 (4)O1—C6—C16—C9179.0 (4)
C8—N1—C9—C16−137.6 (4)C14—C6—C16—C9−2.7 (5)
C14—N1—C9—C16−12.0 (4)O2—C9—C16—C6−170.5 (4)
C3—C7—C10—C13−0.1 (6)N1—C9—C16—C69.2 (5)
C3—C5—C11—C13−0.7 (6)C14—O3—C19—C88.1 (6)
C5—C11—C13—C100.3 (6)N1—C8—C19—O36.7 (5)
C7—C10—C13—C110.1 (6)C3—C8—C19—O3−117.5 (5)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C15—H15C···O2i0.962.543.301 (4)136

Symmetry codes: (i) x+1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WN2289).

References

  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Huang, P.-Q. & Deng, J. (2004). Synlett, pp. 247–250.
  • Huang, P.-Q., Wu, T.-J. & Ruan, Y.-P. (2003). Org. Lett.5, 4341–4344. [PubMed]
  • Jiang, L.-J., Lan, H.-Q., Zheng, J.-F., Ye, J.-L. & Huang, P.-Q. (2009). Synlett In the press.
  • Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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