organic compounds
5,8-Dimethyl-3-methylene-2-oxo-3,3a,4,5,5a,6,8a,8b-octahydro-2H-1-oxa-s-indacene-5-carbaldehyde
aLaboratoire de Chimie Bioorganique et Analytique, URAC 22, BP 146, FSTM, Université Hassan II, Mohammedia-Casablanca 20810 Mohammedia, Morocco, bLaboratoire de Chimie des Substances Naturelles, URAC16, Faculté des Sciences Semlalia, BP 2390 Bd My Abdellah, 40000 Marrakech, Morocco, and cLaboratoire de Chimie de Coordination, 205 route de Narbonne, 31077 Toulouse Cedex 04, France
*Correspondence e-mail: mmoumou17@yahoo.fr
The title compound, C15H18O3, was synthesized from 9α-hydroxyparthenolide (9α-hydroxy-4,8-dimethyl-12-methylene-3,14-dioxatricyclo[9.3.0.02,4]tetradec-7-en-13-one), which was isolated from the chloroform extract of the aerial parts of Anvillea radiata. The five-membered lactone ring has a twisted conformation, while the six- and five-membered rings display chair and envelope conformations, respectively. The dihedral angle between the two five-membered rings is 50.57 (11)°.
Related literature
For the isolation and biological activity of 9α-hydroxyparthenolide, see: Abdel Sattar et al. (1996); El Hassany et al. (2004). For the reactivity of this sesquiterpene, see: Castaneda-Acosta et al. (1993); Neukirch et al. (2003); Der-Ren et al. (2006); Neelakantan et al. (2009). For see: Cremer & Pople (1975).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2005); cell APEX2 and SAINT (Bruker, 2005); 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 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
10.1107/S1600536811018344/sj5146sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811018344/sj5146Isup2.hkl
Boron trifluoride etherate (1 ml, freshly distilled under reduced pressure) was added via syringe over a 10 minute period to a stirred solution of 500 mg (1.89 mmol) of the 9α-hydroxyparthenolide in anhydrous benzene (20 ml), cooled in an ice-bath and maintained under a N2 atmosphere. The ice-bath was then removed and stirring was continued for 2 h during which time the solution became cloudy and reddish in colour. The reaction mixture was poured into cooled water and dichloromethane. After shaking, the layers were separated; the organic layer was treated three time with saturated sodium bicarbonate (3x30ml), dried over sodium sulfate and concentrated under reduced pressure. of the residue obtained on silica gel with hexane/ ethyl acetate (85/15) as allowed us to isolate in pure 300 mg (1.21 mmol) of 5,8-dimethyl-3-methylene - 2-oxo-3,3a,4,5,5a,6,8a,8 b –octahydro-2H-1-oxa-as-indacene-5-carbaldehyde. The title compound was recrystallized from ethyl acetate.
All H atoms were fixed geometrically and treated as riding with C—H = 0.96 Å (methyl), 0.97 Å (methylene), 0.98Å (methine) with Uiso(H) = 1.2Ueq (methylene, methine and OH) or Uiso(H) = 1.5Ueq(methyl). In the absence of significant
the could not be reliably determined and thus 1100 Friedel pairs were merged and any references to the were removed.Data collection: APEX2 (Bruker, 2005); cell
APEX2 and SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); 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, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).C15H18O3 | F(000) = 528 |
Mr = 246.29 | Dx = 1.275 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 22932 reflections |
a = 9.5293 (3) Å | θ = 2.6–26.4° |
b = 9.7885 (3) Å | µ = 0.09 mm−1 |
c = 13.7524 (4) Å | T = 173 K |
V = 1282.79 (7) Å3 | Platelet, colourless |
Z = 4 | 0.50 × 0.33 × 0.08 mm |
Bruker APEXII CCD area-detector diffractometer | 1403 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.026 |
Graphite monochromator | θmax = 26.4°, θmin = 2.6° |
ϕ and ω scans | h = −9→11 |
22932 measured reflections | k = −12→12 |
1517 independent reflections | l = −17→17 |
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)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.085 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0511P)2 + 0.1837P] where P = (Fo2 + 2Fc2)/3 |
1517 reflections | (Δ/σ)max < 0.001 |
165 parameters | Δρmax = 0.18 e Å−3 |
0 restraints | Δρmin = −0.16 e Å−3 |
C15H18O3 | V = 1282.79 (7) Å3 |
Mr = 246.29 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 9.5293 (3) Å | µ = 0.09 mm−1 |
b = 9.7885 (3) Å | T = 173 K |
c = 13.7524 (4) Å | 0.50 × 0.33 × 0.08 mm |
Bruker APEXII CCD area-detector diffractometer | 1403 reflections with I > 2σ(I) |
22932 measured reflections | Rint = 0.026 |
1517 independent reflections |
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.085 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.18 e Å−3 |
1517 reflections | Δρmin = −0.16 e Å−3 |
165 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
C2 | −0.05168 (19) | 0.3323 (2) | 0.83535 (13) | 0.0323 (4) | |
C3 | −0.01615 (19) | 0.47821 (19) | 0.85677 (12) | 0.0307 (4) | |
C3A | 0.12071 (17) | 0.47296 (17) | 0.91013 (12) | 0.0267 (4) | |
H3 | 0.0996 | 0.4573 | 0.9790 | 0.032* | |
C4 | 0.22933 (18) | 0.58577 (18) | 0.90494 (13) | 0.0301 (4) | |
H4A | 0.1903 | 0.6701 | 0.9303 | 0.036* | |
H4B | 0.2568 | 0.6010 | 0.8379 | 0.036* | |
C5 | 0.3576 (2) | 0.54344 (18) | 0.96536 (13) | 0.0311 (4) | |
C5A | 0.40893 (18) | 0.39541 (18) | 0.94628 (13) | 0.0288 (4) | |
H5A | 0.4649 | 0.3698 | 1.0032 | 0.035* | |
C6 | 0.5034 (2) | 0.3693 (2) | 0.85704 (15) | 0.0382 (5) | |
H6A | 0.4700 | 0.4183 | 0.8003 | 0.046* | |
H6B | 0.6000 | 0.3950 | 0.8699 | 0.046* | |
C7 | 0.4886 (2) | 0.2173 (2) | 0.84457 (14) | 0.0377 (4) | |
H7 | 0.5514 | 0.1638 | 0.8095 | 0.045* | |
C8 | 0.3756 (2) | 0.16819 (18) | 0.88923 (12) | 0.0321 (4) | |
C8A | 0.29432 (17) | 0.28351 (16) | 0.93605 (11) | 0.0254 (3) | |
H8A | 0.2558 | 0.2568 | 0.9993 | 0.030* | |
C8B | 0.18260 (17) | 0.34167 (17) | 0.86986 (12) | 0.0252 (3) | |
H8B | 0.2253 | 0.3615 | 0.8066 | 0.030* | |
C9 | −0.0975 (2) | 0.5818 (2) | 0.83263 (14) | 0.0386 (4) | |
H9A | −0.1819 | 0.5660 | 0.8006 | 0.046* | |
H9B | −0.0705 | 0.6706 | 0.8477 | 0.046* | |
C10 | 0.3226 (2) | 0.55169 (19) | 1.07397 (14) | 0.0379 (4) | |
H10 | 0.3857 | 0.5104 | 1.1164 | 0.046* | |
C11 | 0.4789 (2) | 0.6450 (2) | 0.95088 (17) | 0.0439 (5) | |
H11A | 0.4487 | 0.7350 | 0.9691 | 0.066* | |
H11B | 0.5069 | 0.6451 | 0.8838 | 0.066* | |
H11C | 0.5570 | 0.6184 | 0.9907 | 0.066* | |
C12 | 0.3260 (2) | 0.02303 (19) | 0.89327 (14) | 0.0401 (5) | |
H12A | 0.3250 | −0.0075 | 0.9596 | 0.060* | |
H12B | 0.3882 | −0.0337 | 0.8560 | 0.060* | |
H12C | 0.2330 | 0.0173 | 0.8668 | 0.060* | |
O1 | 0.06185 (12) | 0.25263 (13) | 0.85447 (9) | 0.0302 (3) | |
O2 | −0.16069 (14) | 0.28443 (16) | 0.80758 (11) | 0.0455 (4) | |
O3 | 0.22305 (18) | 0.60552 (17) | 1.10965 (11) | 0.0531 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C2 | 0.0276 (9) | 0.0415 (10) | 0.0279 (8) | 0.0015 (8) | 0.0021 (7) | −0.0003 (8) |
C3 | 0.0266 (8) | 0.0389 (9) | 0.0266 (8) | 0.0034 (8) | 0.0031 (7) | 0.0002 (7) |
C3A | 0.0255 (8) | 0.0299 (8) | 0.0249 (7) | 0.0042 (7) | 0.0017 (7) | 0.0012 (7) |
C4 | 0.0310 (9) | 0.0268 (8) | 0.0324 (8) | 0.0032 (8) | −0.0011 (7) | 0.0029 (7) |
C5 | 0.0293 (9) | 0.0276 (8) | 0.0363 (9) | −0.0007 (8) | −0.0049 (7) | 0.0014 (7) |
C5A | 0.0253 (8) | 0.0300 (8) | 0.0311 (8) | 0.0026 (7) | −0.0042 (7) | 0.0048 (7) |
C6 | 0.0260 (9) | 0.0436 (11) | 0.0450 (10) | 0.0037 (8) | 0.0069 (8) | 0.0072 (9) |
C7 | 0.0337 (10) | 0.0403 (10) | 0.0391 (10) | 0.0121 (9) | 0.0021 (8) | −0.0002 (8) |
C8 | 0.0370 (9) | 0.0315 (8) | 0.0277 (8) | 0.0087 (8) | −0.0050 (7) | 0.0024 (7) |
C8A | 0.0284 (8) | 0.0252 (7) | 0.0224 (7) | 0.0017 (7) | −0.0006 (6) | 0.0031 (6) |
C8B | 0.0234 (8) | 0.0284 (8) | 0.0238 (7) | 0.0000 (7) | 0.0024 (6) | 0.0013 (6) |
C9 | 0.0369 (10) | 0.0447 (10) | 0.0341 (9) | 0.0101 (9) | −0.0045 (8) | 0.0023 (8) |
C10 | 0.0452 (11) | 0.0324 (9) | 0.0361 (9) | −0.0010 (9) | −0.0088 (8) | −0.0034 (7) |
C11 | 0.0363 (10) | 0.0347 (10) | 0.0607 (13) | −0.0060 (9) | −0.0088 (10) | 0.0054 (9) |
C12 | 0.0527 (12) | 0.0303 (9) | 0.0373 (9) | 0.0080 (9) | −0.0072 (9) | −0.0012 (8) |
O1 | 0.0274 (6) | 0.0322 (6) | 0.0310 (6) | −0.0012 (5) | −0.0001 (5) | −0.0018 (5) |
O2 | 0.0287 (7) | 0.0547 (9) | 0.0530 (8) | −0.0036 (7) | −0.0043 (6) | −0.0080 (7) |
O3 | 0.0599 (10) | 0.0579 (9) | 0.0414 (8) | 0.0095 (9) | 0.0002 (7) | −0.0130 (7) |
C2—O2 | 1.202 (2) | C6—H6B | 0.9700 |
C2—O1 | 1.360 (2) | C7—C8 | 1.330 (3) |
C2—C3 | 1.497 (3) | C7—H7 | 0.9300 |
C3—C9 | 1.319 (3) | C8—C12 | 1.499 (3) |
C3—C3A | 1.497 (2) | C8—C8A | 1.513 (2) |
C3A—C4 | 1.515 (2) | C8A—C8B | 1.512 (2) |
C3A—C8B | 1.519 (2) | C8A—H8A | 0.9800 |
C3A—H3 | 0.9800 | C8B—O1 | 1.459 (2) |
C4—C5 | 1.535 (2) | C8B—H8B | 0.9800 |
C4—H4A | 0.9700 | C9—H9A | 0.9300 |
C4—H4B | 0.9700 | C9—H9B | 0.9300 |
C5—C10 | 1.533 (3) | C10—O3 | 1.191 (2) |
C5—C11 | 1.538 (3) | C10—H10 | 0.9300 |
C5—C5A | 1.552 (2) | C11—H11A | 0.9600 |
C5A—C6 | 1.544 (3) | C11—H11B | 0.9600 |
C5A—C8A | 1.553 (2) | C11—H11C | 0.9600 |
C5A—H5A | 0.9800 | C12—H12A | 0.9600 |
C6—C7 | 1.504 (3) | C12—H12B | 0.9600 |
C6—H6A | 0.9700 | C12—H12C | 0.9600 |
O2—C2—O1 | 121.68 (18) | C8—C7—H7 | 123.8 |
O2—C2—C3 | 129.07 (18) | C6—C7—H7 | 123.8 |
O1—C2—C3 | 109.23 (15) | C7—C8—C12 | 128.02 (18) |
C9—C3—C2 | 123.43 (17) | C7—C8—C8A | 109.96 (16) |
C9—C3—C3A | 131.43 (18) | C12—C8—C8A | 122.00 (16) |
C2—C3—C3A | 105.12 (14) | C8B—C8A—C8 | 112.67 (13) |
C3—C3A—C4 | 123.15 (14) | C8B—C8A—C5A | 106.51 (13) |
C3—C3A—C8B | 100.87 (14) | C8—C8A—C5A | 101.81 (14) |
C4—C3A—C8B | 109.53 (13) | C8B—C8A—H8A | 111.8 |
C3—C3A—H3 | 107.4 | C8—C8A—H8A | 111.8 |
C4—C3A—H3 | 107.4 | C5A—C8A—H8A | 111.8 |
C8B—C3A—H3 | 107.4 | O1—C8B—C8A | 114.69 (13) |
C3A—C4—C5 | 108.77 (14) | O1—C8B—C3A | 104.61 (13) |
C3A—C4—H4A | 109.9 | C8A—C8B—C3A | 111.88 (13) |
C5—C4—H4A | 109.9 | O1—C8B—H8B | 108.5 |
C3A—C4—H4B | 109.9 | C8A—C8B—H8B | 108.5 |
C5—C4—H4B | 109.9 | C3A—C8B—H8B | 108.5 |
H4A—C4—H4B | 108.3 | C3—C9—H9A | 120.0 |
C10—C5—C4 | 109.89 (16) | C3—C9—H9B | 120.0 |
C10—C5—C11 | 104.81 (16) | H9A—C9—H9B | 120.0 |
C4—C5—C11 | 110.74 (15) | O3—C10—C5 | 126.73 (19) |
C10—C5—C5A | 106.41 (14) | O3—C10—H10 | 116.6 |
C4—C5—C5A | 114.30 (15) | C5—C10—H10 | 116.6 |
C11—C5—C5A | 110.18 (15) | C5—C11—H11A | 109.5 |
C6—C5A—C5 | 118.22 (15) | C5—C11—H11B | 109.5 |
C6—C5A—C8A | 102.79 (14) | H11A—C11—H11B | 109.5 |
C5—C5A—C8A | 116.89 (14) | C5—C11—H11C | 109.5 |
C6—C5A—H5A | 106.0 | H11A—C11—H11C | 109.5 |
C5—C5A—H5A | 106.0 | H11B—C11—H11C | 109.5 |
C8A—C5A—H5A | 106.0 | C8—C12—H12A | 109.5 |
C7—C6—C5A | 101.51 (16) | C8—C12—H12B | 109.5 |
C7—C6—H6A | 111.5 | H12A—C12—H12B | 109.5 |
C5A—C6—H6A | 111.5 | C8—C12—H12C | 109.5 |
C7—C6—H6B | 111.5 | H12A—C12—H12C | 109.5 |
C5A—C6—H6B | 111.5 | H12B—C12—H12C | 109.5 |
H6A—C6—H6B | 109.3 | C2—O1—C8B | 108.23 (13) |
C8—C7—C6 | 112.41 (18) |
Experimental details
Crystal data | |
Chemical formula | C15H18O3 |
Mr | 246.29 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 173 |
a, b, c (Å) | 9.5293 (3), 9.7885 (3), 13.7524 (4) |
V (Å3) | 1282.79 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.50 × 0.33 × 0.08 |
Data collection | |
Diffractometer | Bruker APEXII CCD area-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 22932, 1517, 1403 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.085, 1.09 |
No. of reflections | 1517 |
No. of parameters | 165 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.16 |
Computer programs: APEX2 (Bruker, 2005), APEX2 and SAINT (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
Acknowledgements
The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.
References
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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 natural sesquiterpene lactone (9α - hydroxypartenolide) is the main constituent of the chloroform extract of aerial parts of Anvillea radiata (El Hassany et al., 2004) and of Anvillea garcini (Abdel Sattar et al., 1996). The reactivity of this sesquiterpene lactone and its derivatives has been the subject of several studies (Castaneda-Acosta et al. 1993; Neukirch et al., 2003; Der-Ren et al., 2006; Neelakantan et al., 2009), in order to prepare products with high added value for use in industrial pharmacology. In the same context, we have treated the 9α-hydroxyparthenolide with boron trifluoride etherate and obtained the 5,8-diméthyl-3-methylen-2-oxo-3,3a,4,5,5a,6,8a,8b- octahydro-2H-1-oxa-as-indacene-5-carbaldehyde 64% yield. The structure of this new sesquiterpene derivative of 9α - hydroxypartenolide was determined by 1H and 13C NMR spectral analysis and mass spectrometry, and was confirmed by its single crystal X-ray structure. The molecule contains three fused rings which exhibit different conformations. The molecular structure of (I), Fig.1, shows the lactone ring to adopt a twisted conformation, as indicated by Cremer & Pople (1975) puckering parameters Q = 0.3329 (18) Å and ϕ = 304.4 (3)°. The five-membered ring displays an envelope conformation with Q = 0.340 (2)Å and ϕ = 356.8 (3)°, while the six-membered ring has a chair conformation with QT = 0.5707 (18) Å, θ = 16.39 (18)°, ϕ = 333.5 (7)°.