organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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5,8-Dimeth­­oxy-3,9-di­methyl-3a,4,9,9a-tetra­hydro-4,9-ep­­oxy­naphtho­[2,3-d]isoxazole

aDepartment of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6, Canada, and bDepartment of Chemistry, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
*Correspondence e-mail: alough@chem.utoronto.ca

(Received 19 March 2014; accepted 7 April 2014; online 12 April 2014)

The title compound, C15H17NO4, is the exo isomer with a syn arrangement of the O atom in the isoxazole ring to the methyl group of the bicyclic alkene. The dihedral angle between the isoxazole ring and the benzene ring is 7.42 (9)°. In the crystal, weak C—H⋯O hydrogen bonds link mol­ecules, forming a three-dimensional network. The isoxazole O atom is an acceptor for both weak hydrogen bonds.

Related literature

For 1,3-dipolar cyclo­addition reactions of symmetrical and unsymmetrical bicyclic alkenes, see: Yip et al. (2001[Yip, C., Handerson, S., Tranmer, G. K. & Tam, W. (2001). J. Org. Chem. 66, 276-286.]); Mayo et al. (2001[Mayo, P., Hecnar, T. & Tam, W. (2001). Tetrahedron, 57, 5931-5941.]). For a related structure, see: Lough et al. (2014[Lough, A. J., Nagireddy, J. R. & Tam, W. (2014). Acta Cryst. E70, o543.]).

[Scheme 1]

Experimental

Crystal data
  • C15H17NO4

  • Mr = 275.29

  • Monoclinic, P 21 /n

  • a = 9.0608 (12) Å

  • b = 14.3998 (17) Å

  • c = 10.1631 (12) Å

  • β = 104.835 (3)°

  • V = 1281.8 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 147 K

  • 0.32 × 0.16 × 0.14 mm

Data collection
  • Bruker Kappa APEX DUO CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2012[Bruker (2012). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.660, Tmax = 0.746

  • 11844 measured reflections

  • 2937 independent reflections

  • 2271 reflections with I > 2σ(I)

  • Rint = 0.041

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.097

  • S = 1.05

  • 2937 reflections

  • 185 parameters

  • H-atom parameters constrained

  • Δρmax = 0.28 e Å−3

  • Δρmin = −0.22 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C1—H1A⋯O2i 1.00 2.35 3.2928 (17) 156
C14—H14C⋯O2ii 0.98 2.59 3.5340 (19) 161
Symmetry codes: (i) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (ii) -x+1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2012[Bruker (2012). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2012[Bruker (2012). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Supporting information


Comment top

We have previously investigated the 1,3-dipolar cycloaddition reactions of symmetrical and unsymmetrical bicyclic alkenes (Yip et al., 2001; Mayo et al., 2001). When expanding this reaction with C1-substituted oxabenzonorbornadienes, the bicyclic alkene (III) reacts (see Fig. 1) with acetonitrile oxide (II) (generated in situ) in toluene, to give the cycloadducts (IV) and (V) as regioisomers in the ratio of 89:11 respectively (ratio was determined by 1H NMR). The stereochemistry and regiochemistry of the major product (IV) was determined by this single-crystal X-ray analysis. Although different stereoisomers (exo and endo) could be formed, only the exo stereoisomer was formed with a mixture of the corresponding regioisomers. The major product (IV) obtained was found to be the product with the oxygen of the nitrile oxide syn to the C1-methyl group of the bicyclic alkene.

The molecular structure of the title compound is shown in Fig. 2. The dihedral angle between the isoxazole ring (C4/C5/C6/O2/N1 with an r.m.s. deviation 0.0125 Å) and the benzene ring (C8–C13) is 7.42 (9)°. In the crystal, weak C—H···O hydrogen bonds link molecules forming a three-dimensional network (Fig. 3). The isoxazole O atom is an acceptor for both weak hydrogen bonds. We have prepared by a similar method and carried out the structure determination of a related cycloadduct (Lough et al., 2014)

Related literature top

For 1,3-dipolar cycloaddition reactions of symmetrical and unsymmetrical bicyclic alkenes, see: Yip et al. (2001); Mayo et al. (2001). For a related structure, see: Lough et al. (2014).

Experimental top

A solution of nitroethane (I) (130.0 mg, 1.733 mmol) in toluene (2 ml) was added to a flame-dried flask containing bicyclic alkene (II) (140 mg, 0.642 mmol), (BOC)2O (233.7 mg, 1.07 mmol), DMAP (9.4 mg, 0.077 mmol) and toluene (6 ml) via a cannula over 10 minutes. The reaction mixture was stirred at room temperature for 18 h. The solvent was removed by rotary evaporation, and the crude product was purified by column chromatography (EtOAc:hexanes = 1:9 to 8:2) followed by recrystallization in methanol to give cycloadduct (IV) in 70% yield. Recrystallization of a solution of the title compound in MeOH provided crystals suitable for X-ray diffraction.

Refinement top

Hydrogen atoms were placed in calculated positions with C—H distances of 0.95–1.00 Å and included in the refinement in a riding-model approximation with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(Cmethyl).

Computing details top

Data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The reaction scheme.
[Figure 2] Fig. 2. The molecular structure of the title compound showing 30% probability ellipsoids.
[Figure 3] Fig. 3. Part of the crystal structure with weak hydrogen bonds shown as dashed lines.
5,8-Dimethoxy-3,9-dimethyl-3a,4,9,9a-tetrahydro-4,9-epoxynaphtho[2,3-d]isoxazole top
Crystal data top
C15H17NO4F(000) = 584
Mr = 275.29Dx = 1.427 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 9.0608 (12) ÅCell parameters from 2761 reflections
b = 14.3998 (17) Åθ = 2.5–27.5°
c = 10.1631 (12) ŵ = 0.10 mm1
β = 104.835 (3)°T = 147 K
V = 1281.8 (3) Å3Needle, colourless
Z = 40.32 × 0.16 × 0.14 mm
Data collection top
Bruker Kappa APEX DUO CCD
diffractometer
2271 reflections with I > 2σ(I)
Radiation source: sealed tube with Bruker Triumph monochromatorRint = 0.041
ϕ and ω scansθmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Bruker, 2012)
h = 1111
Tmin = 0.660, Tmax = 0.746k = 1817
11844 measured reflectionsl = 1113
2937 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.039H-atom parameters constrained
wR(F2) = 0.097 w = 1/[σ2(Fo2) + (0.0459P)2 + 0.2574P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
2937 reflectionsΔρmax = 0.28 e Å3
185 parametersΔρmin = 0.22 e Å3
Crystal data top
C15H17NO4V = 1281.8 (3) Å3
Mr = 275.29Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.0608 (12) ŵ = 0.10 mm1
b = 14.3998 (17) ÅT = 147 K
c = 10.1631 (12) Å0.32 × 0.16 × 0.14 mm
β = 104.835 (3)°
Data collection top
Bruker Kappa APEX DUO CCD
diffractometer
2937 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2012)
2271 reflections with I > 2σ(I)
Tmin = 0.660, Tmax = 0.746Rint = 0.041
11844 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.097H-atom parameters constrained
S = 1.05Δρmax = 0.28 e Å3
2937 reflectionsΔρmin = 0.22 e Å3
185 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.50314 (11)0.25637 (7)0.36251 (9)0.0158 (2)
O20.59142 (11)0.27152 (7)0.66027 (10)0.0199 (2)
O30.27204 (11)0.49102 (7)0.15675 (10)0.0217 (2)
O40.89378 (11)0.43196 (7)0.37701 (10)0.0205 (2)
N10.44029 (14)0.24274 (9)0.65909 (12)0.0200 (3)
C10.39743 (15)0.33293 (10)0.34640 (13)0.0147 (3)
H1A0.29090.31900.29270.018*
C20.63942 (15)0.30606 (9)0.43544 (13)0.0147 (3)
C30.77661 (17)0.24375 (10)0.46760 (15)0.0201 (3)
H3A0.80810.23090.38410.030*
H3B0.75100.18530.50600.030*
H3C0.86030.27430.53380.030*
C40.58557 (15)0.34340 (10)0.55933 (13)0.0148 (3)
H4A0.64180.40070.59920.018*
C50.41454 (15)0.36162 (10)0.49764 (13)0.0141 (3)
H5A0.38330.42720.50860.017*
C60.34470 (16)0.29242 (10)0.57416 (14)0.0162 (3)
C70.17703 (16)0.27995 (11)0.55319 (15)0.0203 (3)
H7A0.15800.22820.60920.030*
H7B0.13000.26650.45700.030*
H7C0.13280.33690.57950.030*
C80.47998 (16)0.40647 (10)0.28645 (13)0.0145 (3)
C90.42749 (16)0.48105 (10)0.20091 (14)0.0163 (3)
C100.53678 (17)0.53792 (10)0.16776 (14)0.0178 (3)
H10A0.50520.58850.10700.021*
C110.69228 (17)0.52157 (10)0.22265 (14)0.0182 (3)
H11A0.76470.56090.19760.022*
C120.74383 (16)0.44869 (10)0.31354 (13)0.0153 (3)
C130.63422 (15)0.39029 (9)0.34279 (13)0.0144 (3)
C140.21634 (18)0.57380 (10)0.08270 (15)0.0220 (3)
H14A0.10460.57510.06220.033*
H14B0.24810.57480.00250.033*
H14C0.25810.62820.13760.033*
C151.00530 (17)0.47219 (11)0.31725 (16)0.0227 (3)
H15A1.10700.44990.36520.034*
H15B1.00190.54000.32440.034*
H15C0.98350.45430.22120.034*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0159 (5)0.0130 (5)0.0180 (5)0.0010 (4)0.0035 (4)0.0021 (4)
O20.0152 (5)0.0255 (6)0.0188 (5)0.0024 (4)0.0042 (4)0.0073 (4)
O30.0169 (5)0.0212 (6)0.0255 (5)0.0018 (4)0.0029 (4)0.0078 (4)
O40.0145 (5)0.0259 (6)0.0217 (5)0.0024 (4)0.0057 (4)0.0032 (4)
N10.0188 (6)0.0216 (7)0.0211 (6)0.0009 (5)0.0077 (5)0.0020 (5)
C10.0149 (7)0.0139 (7)0.0149 (6)0.0003 (5)0.0031 (5)0.0003 (5)
C20.0140 (7)0.0143 (7)0.0161 (6)0.0012 (5)0.0044 (5)0.0019 (5)
C30.0192 (8)0.0183 (7)0.0240 (7)0.0035 (6)0.0077 (6)0.0010 (6)
C40.0161 (7)0.0142 (7)0.0144 (6)0.0005 (5)0.0043 (5)0.0010 (5)
C50.0140 (7)0.0133 (7)0.0153 (6)0.0003 (5)0.0044 (5)0.0005 (5)
C60.0197 (7)0.0140 (7)0.0159 (6)0.0006 (6)0.0065 (5)0.0013 (5)
C70.0180 (8)0.0220 (8)0.0228 (7)0.0016 (6)0.0088 (6)0.0004 (6)
C80.0171 (7)0.0139 (7)0.0135 (6)0.0013 (5)0.0055 (5)0.0025 (5)
C90.0171 (7)0.0177 (7)0.0140 (6)0.0011 (6)0.0035 (5)0.0008 (5)
C100.0241 (8)0.0148 (7)0.0149 (6)0.0005 (6)0.0058 (6)0.0009 (5)
C110.0219 (8)0.0173 (7)0.0176 (7)0.0046 (6)0.0092 (6)0.0027 (6)
C120.0151 (7)0.0175 (7)0.0144 (6)0.0007 (6)0.0060 (5)0.0031 (5)
C130.0178 (7)0.0133 (7)0.0127 (6)0.0007 (5)0.0048 (5)0.0026 (5)
C140.0232 (8)0.0204 (8)0.0209 (7)0.0060 (6)0.0029 (6)0.0048 (6)
C150.0165 (7)0.0279 (8)0.0256 (8)0.0038 (6)0.0091 (6)0.0005 (6)
Geometric parameters (Å, º) top
O1—C11.4420 (16)C5—C61.5001 (19)
O1—C21.4550 (16)C5—H5A1.0000
O2—N11.4278 (16)C6—C71.490 (2)
O2—C41.4487 (16)C7—H7A0.9800
O3—C91.3719 (17)C7—H7B0.9800
O3—C141.4309 (17)C7—H7C0.9800
O4—C121.3680 (17)C8—C91.387 (2)
O4—C151.4282 (17)C8—C131.3877 (19)
N1—C61.2744 (19)C9—C101.391 (2)
C1—C81.5118 (18)C10—C111.396 (2)
C1—C51.5605 (18)C10—H10A0.9500
C1—H1A1.0000C11—C121.397 (2)
C2—C31.4997 (19)C11—H11A0.9500
C2—C131.5288 (19)C12—C131.3903 (19)
C2—C41.5580 (18)C14—H14A0.9800
C3—H3A0.9800C14—H14B0.9800
C3—H3B0.9800C14—H14C0.9800
C3—H3C0.9800C15—H15A0.9800
C4—C51.5381 (18)C15—H15B0.9800
C4—H4A1.0000C15—H15C0.9800
C1—O1—C297.72 (10)C7—C6—C5123.78 (12)
N1—O2—C4109.89 (10)C6—C7—H7A109.5
C9—O3—C14116.97 (11)C6—C7—H7B109.5
C12—O4—C15116.97 (11)H7A—C7—H7B109.5
C6—N1—O2109.07 (11)C6—C7—H7C109.5
O1—C1—C8101.45 (10)H7A—C7—H7C109.5
O1—C1—C5101.24 (10)H7B—C7—H7C109.5
C8—C1—C5106.07 (11)C9—C8—C13122.42 (13)
O1—C1—H1A115.4C9—C8—C1132.02 (13)
C8—C1—H1A115.4C13—C8—C1105.43 (12)
C5—C1—H1A115.4O3—C9—C8116.40 (12)
O1—C2—C3111.39 (11)O3—C9—C10126.44 (13)
O1—C2—C13100.84 (10)C8—C9—C10117.16 (13)
C3—C2—C13120.13 (12)C9—C10—C11120.80 (13)
O1—C2—C4100.42 (10)C9—C10—H10A119.6
C3—C2—C4116.36 (11)C11—C10—H10A119.6
C13—C2—C4104.91 (11)C10—C11—C12121.55 (13)
C2—C3—H3A109.5C10—C11—H11A119.2
C2—C3—H3B109.5C12—C11—H11A119.2
H3A—C3—H3B109.5O4—C12—C13118.06 (12)
C2—C3—H3C109.5O4—C12—C11124.58 (13)
H3A—C3—H3C109.5C13—C12—C11117.35 (13)
H3B—C3—H3C109.5C8—C13—C12120.62 (13)
O2—C4—C5105.12 (11)C8—C13—C2104.85 (12)
O2—C4—C2111.31 (11)C12—C13—C2134.47 (13)
C5—C4—C2102.75 (10)O3—C14—H14A109.5
O2—C4—H4A112.3O3—C14—H14B109.5
C5—C4—H4A112.3H14A—C14—H14B109.5
C2—C4—H4A112.3O3—C14—H14C109.5
C6—C5—C4100.96 (11)H14A—C14—H14C109.5
C6—C5—C1112.71 (11)H14B—C14—H14C109.5
C4—C5—C1101.07 (11)O4—C15—H15A109.5
C6—C5—H5A113.6O4—C15—H15B109.5
C4—C5—H5A113.6H15A—C15—H15B109.5
C1—C5—H5A113.6O4—C15—H15C109.5
N1—C6—C7121.36 (13)H15A—C15—H15C109.5
N1—C6—C5114.85 (13)H15B—C15—H15C109.5
C4—O2—N1—C63.33 (15)O1—C1—C8—C1332.41 (13)
C2—O1—C1—C851.19 (11)C5—C1—C8—C1372.97 (13)
C2—O1—C1—C557.97 (11)C14—O3—C9—C8172.37 (12)
C1—O1—C2—C3179.30 (11)C14—O3—C9—C108.0 (2)
C1—O1—C2—C1350.69 (11)C13—C8—C9—O3177.44 (12)
C1—O1—C2—C456.86 (11)C1—C8—C9—O32.2 (2)
N1—O2—C4—C52.76 (13)C13—C8—C9—C102.9 (2)
N1—O2—C4—C2107.78 (12)C1—C8—C9—C10178.11 (13)
O1—C2—C4—O278.42 (12)O3—C9—C10—C11178.30 (13)
C3—C2—C4—O241.92 (16)C8—C9—C10—C112.1 (2)
C13—C2—C4—O2177.29 (11)C9—C10—C11—C120.8 (2)
O1—C2—C4—C533.63 (12)C15—O4—C12—C13161.27 (12)
C3—C2—C4—C5153.97 (12)C15—O4—C12—C1119.88 (19)
C13—C2—C4—C570.66 (12)C10—C11—C12—O4176.08 (12)
O2—C4—C5—C61.30 (13)C10—C11—C12—C132.8 (2)
C2—C4—C5—C6115.27 (11)C9—C8—C13—C120.9 (2)
O2—C4—C5—C1117.31 (11)C1—C8—C13—C12177.18 (12)
C2—C4—C5—C10.74 (13)C9—C8—C13—C2176.63 (12)
O1—C1—C5—C671.58 (13)C1—C8—C13—C20.31 (13)
C8—C1—C5—C6177.12 (11)O4—C12—C13—C8176.95 (12)
O1—C1—C5—C435.38 (12)C11—C12—C13—C81.98 (19)
C8—C1—C5—C470.15 (13)O4—C12—C13—C20.3 (2)
O2—N1—C6—C7178.46 (12)C11—C12—C13—C2178.59 (14)
O2—N1—C6—C52.48 (16)O1—C2—C13—C831.49 (13)
C4—C5—C6—N10.72 (15)C3—C2—C13—C8154.22 (12)
C1—C5—C6—N1106.32 (14)C4—C2—C13—C872.49 (13)
C4—C5—C6—C7179.75 (13)O1—C2—C13—C12151.53 (15)
C1—C5—C6—C772.71 (17)C3—C2—C13—C1228.8 (2)
O1—C1—C8—C9151.77 (14)C4—C2—C13—C12104.49 (17)
C5—C1—C8—C9102.85 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O2i1.002.353.2928 (17)156
C14—H14C···O2ii0.982.593.5340 (19)161
Symmetry codes: (i) x1/2, y+1/2, z1/2; (ii) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O2i1.002.353.2928 (17)156
C14—H14C···O2ii0.982.593.5340 (19)161
Symmetry codes: (i) x1/2, y+1/2, z1/2; (ii) x+1, y+1, z+1.
 

Acknowledgements

This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).

References

First citationBruker (2012). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationLough, A. J., Nagireddy, J. R. & Tam, W. (2014). Acta Cryst. E70, o543.  CSD CrossRef IUCr Journals
First citationMayo, P., Hecnar, T. & Tam, W. (2001). Tetrahedron, 57, 5931–5941.  Web of Science CrossRef CAS
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals
First citationYip, C., Handerson, S., Tranmer, G. K. & Tam, W. (2001). J. Org. Chem. 66, 276–286.  Web of Science CrossRef PubMed CAS

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