organic compounds
(3aRS,7aSR)-7a-Methoxy-2-oxo-2,3,3a,4,5,6,7,7a-octahydro-1-benzofuran-4,4-dicarbonitrile
aDpto. Química Orgánica, Facultade de Química, Universidade de Vigo, E-36310 Vigo, Spain, and bUnidad de Difracción de Raios X de Monocristal, Servicio Determinación Estructural, Proteómica e Xenómica, CACTI-Universidade de Vigo, E-36310 Vigo, Spain
*Correspondence e-mail: magonpe@uvigo.es
The racemic title compound, C11H12N2O3, contains a [4.3.0]bicyclic unit in which the shared C—C bond adopts a cis configuration. The five- and six-membered rings are in twisted envelope (with the bridgehead C atom bearing the methoxy substituent as the flap) and distorted chair conformations, respectively. In the crystal, the molecules are linked via weak C—H⋯O iteractions, forming ladder-like chains along [010].
Related literature
For related syntheses of natural products, see: Jones & Goodbrand (1977). For details of a synthesis using different starting materials, see: Alonso et al. (2005); Pérez et al. (2004, 2005). For a related structure, see: Grudniewska et al. (2011). For puckering parameters, see, Cremer & Pople (1975).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 1998); cell SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2011) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Supporting information
10.1107/S1600536812048519/jj2158sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812048519/jj2158Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812048519/jj2158Isup3.cml
To a solution of 2-(3-(2-methoxy-5-oxo-2,5-dihydrofuran-2-yl)propyl)malononitrile (0.38 mmol) in DMF (3 ml) was added DBU (0.19 mmol, 0.5 eq) and the mixture was stirred at room temperature. At the end of the reaction (TLC), EtOAc (20 ml) was added and the organic layers washed with water (3 x 20 ml), dried (Na2SO4), filtered, and concentrated to afford a residue, which was chromatographed on silica gel giving the title compound. It was then recrystallized using EtOAc/Hexane.
All H atoms were positioned geometrically and refined using a riding model with C—H = 0.96–0.98 Å and Uiso(H) = 1.2Ueq(C) or 1.5 Ueq(Cmethyl).
Data collection: SMART (Bruker, 1998); cell
SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2011) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C11H12N2O3 | F(000) = 464 |
Mr = 220.23 | Dx = 1.357 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 1285 reflections |
a = 11.816 (3) Å | θ = 2.7–22.8° |
b = 7.228 (2) Å | µ = 0.10 mm−1 |
c = 13.017 (4) Å | T = 293 K |
β = 104.250 (5)° | Prism, colourless |
V = 1077.6 (5) Å3 | 0.49 × 0.24 × 0.19 mm |
Z = 4 |
Bruker SMART 1000 CCD diffractometer | 1893 independent reflections |
Radiation source: fine-focus sealed tube | 1244 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
ϕ and ω scans | θmax = 25.0°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −13→14 |
Tmin = 0.697, Tmax = 0.745 | k = −8→8 |
5473 measured reflections | l = −14→15 |
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)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.143 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0722P)2 + 0.3369P] where P = (Fo2 + 2Fc2)/3 |
1893 reflections | (Δ/σ)max < 0.001 |
146 parameters | Δρmax = 0.45 e Å−3 |
0 restraints | Δρmin = −0.19 e Å−3 |
C11H12N2O3 | V = 1077.6 (5) Å3 |
Mr = 220.23 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.816 (3) Å | µ = 0.10 mm−1 |
b = 7.228 (2) Å | T = 293 K |
c = 13.017 (4) Å | 0.49 × 0.24 × 0.19 mm |
β = 104.250 (5)° |
Bruker SMART 1000 CCD diffractometer | 1893 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1244 reflections with I > 2σ(I) |
Tmin = 0.697, Tmax = 0.745 | Rint = 0.030 |
5473 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.143 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.45 e Å−3 |
1893 reflections | Δρmin = −0.19 e Å−3 |
146 parameters |
Experimental. [mp: 175–177 °C; IR (neat): 2248, 1800, 1744 cm-1; 1H NMR (CDCl3): δ: 3.38 (3H, s, OMe); 3.21 (1H, dd, J = 7.60, 17.78); 2.86 (1H, dd, J = 3.53, 7.60); 2.70 (1H, dd, J = 3.53, 17.78); 2.39–2.33 (2H, m); 2.16–1.80 (4H, m); 13C NMR (CDCl3): δ: 171.69 (C=O); 114.67 (CN); 112.89 (CN); 105.51 (C); 50.05 (OMe); 45.74 (CH); 35.79 (CH2); 33.59 (CH2); 31.89 (CH2); 28.56 (CH2); 17.68 (CH2); HRMS: calcd for C11H13N2O3 [M+1H]+ 221.0926, found 221.0583]. |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.67913 (13) | 0.7856 (2) | 0.36232 (13) | 0.0423 (5) | |
O2 | 0.67361 (18) | 0.5064 (3) | 0.43402 (17) | 0.0660 (6) | |
O3 | 0.63413 (13) | 1.0294 (2) | 0.45900 (12) | 0.0401 (4) | |
N41 | 0.2043 (2) | 0.7955 (4) | 0.1943 (2) | 0.0671 (7) | |
N42 | 0.5146 (2) | 0.5424 (4) | 0.1555 (2) | 0.0700 (8) | |
C2 | 0.6249 (2) | 0.6485 (4) | 0.4044 (2) | 0.0454 (6) | |
C3 | 0.5029 (2) | 0.7069 (3) | 0.40461 (19) | 0.0415 (6) | |
H3A | 0.4961 | 0.7318 | 0.4761 | 0.050* | |
H3B | 0.4467 | 0.6125 | 0.3731 | 0.050* | |
C3A | 0.48499 (18) | 0.8826 (3) | 0.33778 (17) | 0.0344 (6) | |
H3 | 0.4371 | 0.9708 | 0.3658 | 0.041* | |
C4 | 0.42864 (19) | 0.8445 (3) | 0.21834 (18) | 0.0394 (6) | |
C5 | 0.4493 (2) | 1.0080 (4) | 0.14904 (19) | 0.0464 (7) | |
H5A | 0.4119 | 0.9828 | 0.0753 | 0.056* | |
H5B | 0.4150 | 1.1195 | 0.1698 | 0.056* | |
C6 | 0.5794 (2) | 1.0369 (4) | 0.1619 (2) | 0.0508 (7) | |
H6A | 0.5916 | 1.1360 | 0.1155 | 0.061* | |
H6B | 0.6137 | 0.9250 | 0.1415 | 0.061* | |
C7 | 0.6392 (2) | 1.0854 (4) | 0.27642 (19) | 0.0453 (6) | |
H7A | 0.7230 | 1.0856 | 0.2845 | 0.054* | |
H7B | 0.6164 | 1.2097 | 0.2911 | 0.054* | |
C7A | 0.61086 (19) | 0.9552 (3) | 0.35683 (18) | 0.0352 (6) | |
C8 | 0.7522 (2) | 1.0884 (4) | 0.5017 (2) | 0.0520 (7) | |
H8A | 0.8048 | 0.9939 | 0.4902 | 0.078* | |
H8B | 0.7645 | 1.1105 | 0.5764 | 0.078* | |
H8C | 0.7662 | 1.2004 | 0.4672 | 0.078* | |
C42 | 0.4769 (2) | 0.6739 (4) | 0.1824 (2) | 0.0483 (7) | |
C41 | 0.3020 (2) | 0.8146 (4) | 0.2047 (2) | 0.0460 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0349 (9) | 0.0400 (10) | 0.0545 (10) | 0.0055 (7) | 0.0155 (8) | −0.0029 (8) |
O2 | 0.0677 (13) | 0.0411 (12) | 0.0881 (16) | 0.0172 (10) | 0.0173 (11) | 0.0123 (10) |
O3 | 0.0359 (9) | 0.0462 (10) | 0.0375 (9) | −0.0036 (7) | 0.0078 (7) | −0.0089 (7) |
N41 | 0.0405 (14) | 0.086 (2) | 0.0718 (17) | −0.0063 (13) | 0.0091 (12) | −0.0035 (14) |
N42 | 0.0580 (16) | 0.0740 (19) | 0.0745 (18) | 0.0034 (14) | 0.0096 (13) | −0.0302 (15) |
C2 | 0.0500 (15) | 0.0367 (15) | 0.0489 (15) | 0.0027 (12) | 0.0113 (12) | −0.0013 (12) |
C3 | 0.0409 (14) | 0.0411 (14) | 0.0440 (14) | −0.0036 (11) | 0.0133 (11) | −0.0006 (12) |
C3A | 0.0316 (12) | 0.0379 (13) | 0.0357 (13) | 0.0007 (10) | 0.0122 (10) | −0.0021 (10) |
C4 | 0.0320 (12) | 0.0472 (15) | 0.0388 (13) | 0.0008 (10) | 0.0080 (10) | −0.0043 (11) |
C5 | 0.0462 (15) | 0.0574 (17) | 0.0358 (14) | 0.0016 (12) | 0.0102 (11) | 0.0048 (11) |
C6 | 0.0494 (16) | 0.0640 (19) | 0.0424 (15) | −0.0038 (13) | 0.0177 (12) | 0.0042 (13) |
C7 | 0.0438 (14) | 0.0470 (15) | 0.0468 (15) | −0.0060 (12) | 0.0146 (11) | 0.0027 (12) |
C7A | 0.0330 (12) | 0.0357 (13) | 0.0384 (13) | 0.0012 (10) | 0.0113 (10) | −0.0041 (10) |
C8 | 0.0449 (15) | 0.0523 (16) | 0.0527 (16) | −0.0055 (13) | 0.0003 (12) | −0.0030 (13) |
C42 | 0.0392 (14) | 0.0572 (18) | 0.0473 (15) | −0.0049 (13) | 0.0081 (12) | −0.0164 (14) |
C41 | 0.0390 (15) | 0.0535 (17) | 0.0446 (15) | −0.0012 (12) | 0.0086 (11) | −0.0042 (12) |
O1—C2 | 1.366 (3) | C4—C42 | 1.482 (4) |
O1—C7A | 1.460 (3) | C4—C5 | 1.542 (3) |
O2—C2 | 1.194 (3) | C5—C6 | 1.519 (4) |
O3—C7A | 1.397 (3) | C5—H5A | 0.9700 |
O3—C8 | 1.433 (3) | C5—H5B | 0.9700 |
N41—C41 | 1.137 (3) | C6—C7 | 1.525 (4) |
N42—C42 | 1.141 (3) | C6—H6A | 0.9700 |
C2—C3 | 1.503 (3) | C6—H6B | 0.9700 |
C3—C3A | 1.524 (3) | C7—C7A | 1.505 (3) |
C3—H3A | 0.9700 | C7—H7A | 0.9700 |
C3—H3B | 0.9700 | C7—H7B | 0.9700 |
C3A—C7A | 1.539 (3) | C8—H8A | 0.9600 |
C3A—C4 | 1.558 (3) | C8—H8B | 0.9600 |
C3A—H3 | 0.9800 | C8—H8C | 0.9600 |
C4—C41 | 1.479 (3) | ||
C2—O1—C7A | 108.73 (17) | H5A—C5—H5B | 108.2 |
C7A—O3—C8 | 115.36 (17) | C5—C6—C7 | 110.6 (2) |
O2—C2—O1 | 121.2 (2) | C5—C6—H6A | 109.5 |
O2—C2—C3 | 128.8 (2) | C7—C6—H6A | 109.5 |
O1—C2—C3 | 110.0 (2) | C5—C6—H6B | 109.5 |
C2—C3—C3A | 103.38 (18) | C7—C6—H6B | 109.5 |
C2—C3—H3A | 111.1 | H6A—C6—H6B | 108.1 |
C3A—C3—H3A | 111.1 | C7A—C7—C6 | 114.0 (2) |
C2—C3—H3B | 111.1 | C7A—C7—H7A | 108.7 |
C3A—C3—H3B | 111.1 | C6—C7—H7A | 108.7 |
H3A—C3—H3B | 109.1 | C7A—C7—H7B | 108.7 |
C3—C3A—C7A | 101.50 (17) | C6—C7—H7B | 108.7 |
C3—C3A—C4 | 112.80 (19) | H7A—C7—H7B | 107.6 |
C7A—C3A—C4 | 112.33 (17) | O3—C7A—O1 | 107.39 (18) |
C3—C3A—H3 | 110.0 | O3—C7A—C7 | 113.4 (2) |
C7A—C3A—H3 | 110.0 | O1—C7A—C7 | 110.14 (18) |
C4—C3A—H3 | 110.0 | O3—C7A—C3A | 103.91 (17) |
C41—C4—C42 | 107.3 (2) | O1—C7A—C3A | 102.82 (18) |
C41—C4—C5 | 110.1 (2) | C7—C7A—C3A | 118.23 (19) |
C42—C4—C5 | 108.9 (2) | O3—C8—H8A | 109.5 |
C41—C4—C3A | 108.48 (18) | O3—C8—H8B | 109.5 |
C42—C4—C3A | 111.02 (19) | H8A—C8—H8B | 109.5 |
C5—C4—C3A | 110.99 (19) | O3—C8—H8C | 109.5 |
C6—C5—C4 | 110.0 (2) | H8A—C8—H8C | 109.5 |
C6—C5—H5A | 109.7 | H8B—C8—H8C | 109.5 |
C4—C5—H5A | 109.7 | N42—C42—C4 | 179.5 (3) |
C6—C5—H5B | 109.7 | N41—C41—C4 | 178.6 (3) |
C4—C5—H5B | 109.7 | ||
C7A—O1—C2—O2 | −166.8 (2) | C8—O3—C7A—C3A | 173.04 (19) |
C7A—O1—C2—C3 | 13.8 (3) | C2—O1—C7A—O3 | 77.4 (2) |
O2—C2—C3—C3A | −169.1 (3) | C2—O1—C7A—C7 | −158.74 (19) |
O1—C2—C3—C3A | 10.3 (3) | C2—O1—C7A—C3A | −31.9 (2) |
C2—C3—C3A—C7A | −28.3 (2) | C6—C7—C7A—O3 | −160.9 (2) |
C2—C3—C3A—C4 | 92.2 (2) | C6—C7—C7A—O1 | 78.7 (2) |
C3—C3A—C4—C41 | 78.0 (2) | C6—C7—C7A—C3A | −39.0 (3) |
C7A—C3A—C4—C41 | −168.0 (2) | C3—C3A—C7A—O3 | −75.5 (2) |
C3—C3A—C4—C42 | −39.6 (2) | C4—C3A—C7A—O3 | 163.78 (18) |
C7A—C3A—C4—C42 | 74.3 (2) | C3—C3A—C7A—O1 | 36.4 (2) |
C3—C3A—C4—C5 | −160.97 (18) | C4—C3A—C7A—O1 | −84.4 (2) |
C7A—C3A—C4—C5 | −47.0 (3) | C3—C3A—C7A—C7 | 157.9 (2) |
C41—C4—C5—C6 | −179.2 (2) | C4—C3A—C7A—C7 | 37.2 (3) |
C42—C4—C5—C6 | −61.8 (3) | C41—C4—C42—N42 | −121 (39) |
C3A—C4—C5—C6 | 60.7 (3) | C5—C4—C42—N42 | 120 (39) |
C4—C5—C6—C7 | −61.9 (3) | C3A—C4—C42—N42 | −3 (40) |
C5—C6—C7—C7A | 50.4 (3) | C42—C4—C41—N41 | −160 (11) |
C8—O3—C7A—O1 | 64.6 (2) | C5—C4—C41—N41 | −42 (11) |
C8—O3—C7A—C7 | −57.3 (3) | C3A—C4—C41—N41 | 80 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3A···O3i | 0.97 | 2.59 | 3.290 (3) | 129 |
C8—H8C···O2ii | 0.96 | 2.46 | 3.219 (4) | 136 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C11H12N2O3 |
Mr | 220.23 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 11.816 (3), 7.228 (2), 13.017 (4) |
β (°) | 104.250 (5) |
V (Å3) | 1077.6 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.49 × 0.24 × 0.19 |
Data collection | |
Diffractometer | Bruker SMART 1000 CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.697, 0.745 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5473, 1893, 1244 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.143, 1.03 |
No. of reflections | 1893 |
No. of parameters | 146 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.45, −0.19 |
Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2011) and Mercury (Macrae et al., 2006), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3A···O3i | 0.97 | 2.59 | 3.290 (3) | 129.3 |
C8—H8C···O2ii | 0.96 | 2.46 | 3.219 (4) | 136.0 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) x, y+1, z. |
Acknowledgements
This work was supported financially by the Spanish Ministry of Foreign Affairs and Cooperation (PCIA/030052/10) and the Xunta de Galicia (INCITE845B-2010/020, INCITE08PXIB314255PR).
References
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The racemic title compound is a [4.3.0] bicyclic γ-lactone obtained through an intramolecular Michael addition. The construction of carbocyclic systems is of paramount importance in organic synthesis since they are intermediate compounds for the preparation of interesting natural products (Jones et al., 1977) as carbocyclic nucleosides and vitamin D analogues. We have described a new methodology for the synthesis of oxacyclic compounds using either methoxyallene (Alonso et al., 2005) or furan (Pérez et al., 2005) as a starting material. In the title compound (Fig. 1), the C—C share bond of the bicyclic moiety adopts a cis configuration. The 5-membered ring adopts a twisted envelope conformation with puckering parameters Q = 0.358 (2) Å and ϕ = 126.7 (4)° (Cremer & Pople, 1975) and the 6-membered ring adopts a distorted chair conformation with puckering parameters Q = 0.531 (3) Å, θ = 19.3 (3)° and ϕ = 123.3 (9)° (Cremer & Pople (1975). All bond lengths and bond angles are normal comparable to those observed in similar crystal structures (Grudniewska et al., 2011). In the crystal structure, the molecules are self-assembled via weak C—H···O intermolecular interactions (Table 1) to form a ladderlike chain structure along [010] (Fig. 2).