organic compounds
(3S,7aR)-7-Methoxy-7a-methyl-3-phenyl-2,3-dihydropyrrolo[2,1-b]oxazol-5(7aH)-one
aThe Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
*Correspondence e-mail: yejl@xmu.edu.cn
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 is stabilized by intermolecular C—H⋯O hydrogen bonds.
Related literature
For reference bond-length data, see: Allen et al. (1987). For the chemistry of tetramic acids and methyl tetramates, see: Huang & Deng (2004); Huang et al. (2003); Jiang et al. (2009).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536808040105/wn2289sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808040105/wn2289Isup2.hkl
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
and yielded a mixture of To the mixture of (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 to yield the title compound. Single crystals were obtained by slow evaporation of a petroleum ether / ethyl acetate solution.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
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 effects, Friedel pairs were merged.Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell
CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C14H15NO3 | F(000) = 260 |
Mr = 245.27 | Dx = 1.295 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 672 reflections |
a = 7.8238 (10) Å | θ = 2.9–32.6° |
b = 5.9033 (7) Å | µ = 0.09 mm−1 |
c = 13.711 (3) Å | T = 293 K |
β = 96.597 (14)° | Needle, colourless |
V = 629.05 (16) Å3 | 0.40 × 0.18 × 0.12 mm |
Z = 2 |
Oxford Diffraction Gemini S Ultra diffractometer | 1170 independent reflections |
Radiation source: fine-focus sealed tube | 691 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.067 |
ϕ and ω scans | θmax = 25.0°, θmin = 2.9° |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) | h = −9→9 |
Tmin = 0.964, Tmax = 0.984 | k = −4→7 |
3205 measured reflections | l = −16→14 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.076 | H-atom parameters constrained |
S = 0.89 | w = 1/[σ2(Fo2) + (0.0229P)2] where P = (Fo2 + 2Fc2)/3 |
1170 reflections | (Δ/σ)max = 0.016 |
163 parameters | Δρmax = 0.16 e Å−3 |
1 restraint | Δρmin = −0.15 e Å−3 |
C14H15NO3 | V = 629.05 (16) Å3 |
Mr = 245.27 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 7.8238 (10) Å | µ = 0.09 mm−1 |
b = 5.9033 (7) Å | T = 293 K |
c = 13.711 (3) Å | 0.40 × 0.18 × 0.12 mm |
β = 96.597 (14)° |
Oxford Diffraction Gemini S Ultra diffractometer | 1170 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) | 691 reflections with I > 2σ(I) |
Tmin = 0.964, Tmax = 0.984 | Rint = 0.067 |
3205 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 1 restraint |
wR(F2) = 0.076 | H-atom parameters constrained |
S = 0.89 | Δρmax = 0.16 e Å−3 |
1170 reflections | Δρmin = −0.15 e Å−3 |
163 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.1601 (4) | 0.4015 (5) | 0.7374 (3) | 0.0243 (9) | |
O2 | −0.1216 (3) | 0.4978 (5) | 0.6847 (3) | 0.0474 (10) | |
C3 | 0.1854 (5) | 0.2927 (6) | 0.9142 (4) | 0.0283 (12) | |
O1 | 0.3713 (4) | 0.3770 (5) | 0.5217 (3) | 0.0460 (9) | |
C5 | 0.2722 (5) | 0.4920 (7) | 0.9416 (4) | 0.0340 (12) | |
H5A | 0.2952 | 0.5946 | 0.8934 | 0.041* | |
C6 | 0.2535 (5) | 0.4025 (7) | 0.5833 (4) | 0.0323 (11) | |
C7 | 0.1517 (5) | 0.1443 (7) | 0.9894 (4) | 0.0340 (13) | |
H7A | 0.0933 | 0.0095 | 0.9740 | 0.041* | |
C8 | 0.1279 (5) | 0.2310 (7) | 0.8097 (4) | 0.0309 (12) | |
H8A | 0.0044 | 0.1977 | 0.8030 | 0.037* | |
C9 | 0.0262 (5) | 0.4666 (6) | 0.6652 (4) | 0.0310 (11) | |
C10 | 0.2041 (5) | 0.1961 (8) | 1.0856 (5) | 0.0416 (13) | |
H10A | 0.1807 | 0.0959 | 1.1347 | 0.050* | |
C11 | 0.3251 (6) | 0.5415 (8) | 1.0386 (4) | 0.0437 (14) | |
H11A | 0.3842 | 0.6753 | 1.0551 | 0.052* | |
O3 | 0.3124 (4) | 0.0915 (5) | 0.6977 (3) | 0.0601 (12) | |
C13 | 0.2908 (5) | 0.3940 (8) | 1.1107 (4) | 0.0418 (13) | |
H13A | 0.3259 | 0.4272 | 1.1762 | 0.050* | |
C14 | 0.3068 (5) | 0.3310 (7) | 0.6872 (4) | 0.0339 (12) | |
C15 | 0.4755 (5) | 0.4379 (9) | 0.7300 (4) | 0.0503 (14) | |
H15A | 0.5033 | 0.3885 | 0.7966 | 0.075* | |
H15B | 0.4645 | 0.5998 | 0.7284 | 0.075* | |
H15C | 0.5654 | 0.3929 | 0.6919 | 0.075* | |
C16 | 0.0944 (5) | 0.4851 (7) | 0.5732 (4) | 0.0386 (13) | |
H16A | 0.0370 | 0.5450 | 0.5158 | 0.046* | |
C17 | 0.3234 (7) | 0.4610 (10) | 0.4231 (4) | 0.0636 (16) | |
H17A | 0.4160 | 0.4352 | 0.3842 | 0.095* | |
H17B | 0.3001 | 0.6204 | 0.4255 | 0.095* | |
H17C | 0.2223 | 0.3830 | 0.3942 | 0.095* | |
C19 | 0.2233 (7) | 0.0254 (7) | 0.7733 (5) | 0.0562 (17) | |
H19A | 0.3023 | −0.0355 | 0.8266 | 0.067* | |
H19B | 0.1414 | −0.0921 | 0.7509 | 0.067* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0233 (17) | 0.0272 (18) | 0.022 (3) | 0.0013 (15) | 0.0014 (17) | 0.0048 (18) |
O2 | 0.0300 (16) | 0.069 (2) | 0.043 (3) | 0.0111 (17) | 0.0055 (16) | 0.0099 (19) |
C3 | 0.026 (2) | 0.026 (3) | 0.034 (4) | 0.0031 (18) | 0.005 (2) | 0.002 (2) |
O1 | 0.0494 (19) | 0.0528 (19) | 0.039 (3) | −0.0044 (17) | 0.0195 (19) | −0.003 (2) |
C5 | 0.042 (2) | 0.023 (2) | 0.037 (4) | −0.001 (2) | 0.002 (2) | −0.003 (3) |
C6 | 0.036 (3) | 0.029 (2) | 0.033 (3) | −0.012 (2) | 0.007 (2) | −0.005 (2) |
C7 | 0.027 (2) | 0.029 (3) | 0.046 (4) | −0.0049 (18) | 0.004 (3) | −0.001 (3) |
C8 | 0.034 (2) | 0.025 (2) | 0.033 (4) | −0.011 (2) | 0.001 (2) | −0.003 (2) |
C9 | 0.029 (2) | 0.030 (2) | 0.034 (3) | −0.002 (2) | 0.004 (2) | 0.000 (2) |
C10 | 0.035 (3) | 0.052 (3) | 0.036 (4) | 0.003 (3) | −0.001 (3) | 0.012 (3) |
C11 | 0.054 (3) | 0.036 (3) | 0.039 (4) | −0.005 (2) | −0.008 (3) | −0.004 (3) |
O3 | 0.068 (2) | 0.035 (2) | 0.086 (4) | 0.0224 (16) | 0.047 (2) | 0.020 (2) |
C13 | 0.041 (3) | 0.058 (3) | 0.023 (3) | 0.013 (3) | −0.009 (2) | 0.004 (3) |
C14 | 0.029 (2) | 0.030 (3) | 0.044 (4) | 0.010 (2) | 0.011 (2) | 0.006 (2) |
C15 | 0.030 (2) | 0.078 (4) | 0.043 (4) | −0.004 (3) | 0.003 (2) | 0.004 (3) |
C16 | 0.030 (2) | 0.042 (3) | 0.041 (4) | −0.001 (2) | −0.005 (2) | 0.007 (3) |
C17 | 0.079 (4) | 0.074 (4) | 0.040 (4) | −0.025 (3) | 0.018 (3) | −0.004 (4) |
C19 | 0.082 (4) | 0.032 (3) | 0.059 (5) | −0.006 (3) | 0.024 (4) | −0.003 (3) |
N1—C9 | 1.410 (5) | C10—C13 | 1.374 (7) |
N1—C8 | 1.455 (5) | C10—H10A | 0.9300 |
N1—C14 | 1.465 (5) | C11—C13 | 1.366 (7) |
O2—C9 | 1.230 (4) | C11—H11A | 0.9300 |
C3—C5 | 1.389 (5) | O3—C19 | 1.371 (6) |
C3—C7 | 1.402 (6) | O3—C14 | 1.421 (5) |
C3—C8 | 1.497 (7) | C13—H13A | 0.9300 |
O1—C6 | 1.329 (5) | C14—C15 | 1.519 (6) |
O1—C17 | 1.448 (7) | C15—H15A | 0.9600 |
C5—C11 | 1.378 (7) | C15—H15B | 0.9600 |
C5—H5A | 0.9300 | C15—H15C | 0.9600 |
C6—C16 | 1.329 (5) | C16—H16A | 0.9300 |
C6—C14 | 1.498 (7) | C17—H17A | 0.9600 |
C7—C10 | 1.369 (7) | C17—H17B | 0.9600 |
C7—H7A | 0.9300 | C17—H17C | 0.9600 |
C8—C19 | 1.538 (6) | C19—H19A | 0.9700 |
C8—H8A | 0.9800 | C19—H19B | 0.9700 |
C9—C16 | 1.429 (6) | ||
C9—N1—C8 | 119.6 (3) | C19—O3—C14 | 110.3 (4) |
C9—N1—C14 | 107.9 (4) | C11—C13—C10 | 119.5 (5) |
C8—N1—C14 | 109.3 (3) | C11—C13—H13A | 120.2 |
C5—C3—C7 | 117.2 (5) | C10—C13—H13A | 120.2 |
C5—C3—C8 | 123.4 (4) | O3—C14—N1 | 104.6 (3) |
C7—C3—C8 | 119.5 (4) | O3—C14—C6 | 112.3 (4) |
C6—O1—C17 | 115.5 (4) | N1—C14—C6 | 102.6 (3) |
C11—C5—C3 | 121.7 (5) | O3—C14—C15 | 111.0 (4) |
C11—C5—H5A | 119.2 | N1—C14—C15 | 113.2 (4) |
C3—C5—H5A | 119.2 | C6—C14—C15 | 112.6 (4) |
O1—C6—C16 | 133.2 (5) | C14—C15—H15A | 109.5 |
O1—C6—C14 | 115.8 (4) | C14—C15—H15B | 109.5 |
C16—C6—C14 | 111.0 (4) | H15A—C15—H15B | 109.5 |
C10—C7—C3 | 120.6 (4) | C14—C15—H15C | 109.5 |
C10—C7—H7A | 119.7 | H15A—C15—H15C | 109.5 |
C3—C7—H7A | 119.7 | H15B—C15—H15C | 109.5 |
N1—C8—C3 | 115.3 (3) | C6—C16—C9 | 108.7 (5) |
N1—C8—C19 | 101.3 (4) | C6—C16—H16A | 125.7 |
C3—C8—C19 | 113.5 (4) | C9—C16—H16A | 125.7 |
N1—C8—H8A | 108.8 | O1—C17—H17A | 109.5 |
C3—C8—H8A | 108.8 | O1—C17—H17B | 109.5 |
C19—C8—H8A | 108.8 | H17A—C17—H17B | 109.5 |
O2—C9—N1 | 122.0 (4) | O1—C17—H17C | 109.5 |
O2—C9—C16 | 129.5 (5) | H17A—C17—H17C | 109.5 |
N1—C9—C16 | 108.5 (3) | H17B—C17—H17C | 109.5 |
C7—C10—C13 | 121.0 (5) | O3—C19—C8 | 109.2 (4) |
C7—C10—H10A | 119.5 | O3—C19—H19A | 109.8 |
C13—C10—H10A | 119.5 | C8—C19—H19A | 109.8 |
C13—C11—C5 | 120.0 (5) | O3—C19—H19B | 109.8 |
C13—C11—H11A | 120.0 | C8—C19—H19B | 109.8 |
C5—C11—H11A | 120.0 | H19A—C19—H19B | 108.3 |
C7—C3—C5—C11 | 0.7 (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—C16 | 2.4 (7) | C19—O3—C14—C15 | 103.0 (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—O3 | 24.0 (5) |
C8—C3—C7—C10 | 179.5 (4) | C9—N1—C14—C6 | 9.9 (4) |
C9—N1—C8—C3 | −130.6 (4) | C8—N1—C14—C6 | 141.4 (3) |
C14—N1—C8—C3 | 104.4 (4) | C9—N1—C14—C15 | 131.5 (4) |
C9—N1—C8—C19 | 106.3 (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—O3 | 107.3 (4) |
C7—C3—C8—N1 | 176.7 (3) | O1—C6—C14—N1 | 174.2 (3) |
C5—C3—C8—C19 | 112.8 (4) | C16—C6—C14—N1 | −4.4 (5) |
C7—C3—C8—C19 | −67.0 (5) | O1—C6—C14—C15 | 52.1 (5) |
C8—N1—C9—O2 | 42.2 (6) | C16—C6—C14—C15 | −126.5 (4) |
C14—N1—C9—O2 | 167.8 (4) | O1—C6—C16—C9 | 179.0 (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—C6 | 9.2 (5) |
C3—C5—C11—C13 | −0.7 (6) | C14—O3—C19—C8 | 8.1 (6) |
C5—C11—C13—C10 | 0.3 (6) | N1—C8—C19—O3 | 6.7 (5) |
C7—C10—C13—C11 | 0.1 (6) | C3—C8—C19—O3 | −117.5 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
C15—H15C···O2i | 0.96 | 2.54 | 3.301 (4) | 136 |
Symmetry code: (i) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C14H15NO3 |
Mr | 245.27 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 293 |
a, b, c (Å) | 7.8238 (10), 5.9033 (7), 13.711 (3) |
β (°) | 96.597 (14) |
V (Å3) | 629.05 (16) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.40 × 0.18 × 0.12 |
Data collection | |
Diffractometer | Oxford Diffraction Gemini S Ultra diffractometer |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2008) |
Tmin, Tmax | 0.964, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3205, 1170, 691 |
Rint | 0.067 |
(sin θ/λ)max (Å−1) | 0.594 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.076, 0.89 |
No. of reflections | 1170 |
No. of parameters | 163 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.16, −0.15 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SHELXTL (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
C15—H15C···O2i | 0.96 | 2.54 | 3.301 (4) | 136.4 |
Symmetry code: (i) x+1, y, z. |
Acknowledgements
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.
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. CrossRef Web of Science Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Huang, P.-Q. & Deng, J. (2004). Synlett, pp. 247–250. Web of Science CrossRef Google Scholar
Huang, P.-Q., Wu, T.-J. & Ruan, Y.-P. (2003). Org. Lett. 5, 4341–4344. Web of Science CrossRef PubMed CAS Google Scholar
Jiang, L.-J., Lan, H.-Q., Zheng, J.-F., Ye, J.-L. & Huang, P.-Q. (2009). Synlett. In the press. Google Scholar
Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
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.