7α-Methoxy­carbonyl-6,7,8,14-tetra­hydro-6,14-endo-ethenothebaine

Mustafa Odabaşoğlu; Serkan Yavuz; Özgür Pamir; Yılmaz Yıldırır; Orhan Büyükgüngör

doi:10.1107/S1600536809009362

. 2009 Mar 25;65(Pt 4):o864. doi: 10.1107/S1600536809009362

7α-Methoxycarbonyl-6,7,8,14-tetrahydro-6,14-endo-ethenothebaine

Mustafa Odabaşoğlu ^a, Serkan Yavuz ^b, Özgür Pamir ^b, Yılmaz Yıldırır ^b, Orhan Büyükgüngör ^c,^*

PMCID: PMC2968994 PMID: 21582578

Abstract

In the molecule of the title compound, C₂₃H₂₇NO₅, the furan ring adopts an envelope conformation. Intramolecular C—H⋯O interactions result in the formation of S(5) and S(6) motifs. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link the molecules through C(6) and C(8) chains along the [100] and [010] directions, generating a two-dimensional network.

Related literature

For general background, see: Casy & Parfitt (1986 ▶); Lenz et al. (1986 ▶); Schmidhammer, (1998 ▶); Maat et al. (1999 ▶); Lewis (1985 ▶). For a related structure, see: Bentley & Hardy (1967 ▶). For bond-length data, see: Allen et al. (1987 ▶). For ring-puckering parameters, see: Cremer & Pople (1975 ▶). For ring motifs, see: Bernstein et al. (1995 ▶); Etter (1990 ▶).

Experimental

Crystal data

C₂₃H₂₇NO₅
M _r = 397.46
Orthorhombic,
a = 6.5604 (2) Å
b = 10.4082 (3) Å
c = 29.1382 (11) Å
V = 1989.61 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.39 × 0.35 × 0.31 mm

Data collection

Stoe IPDS II diffractometer
Absorption correction: integration (X-RED32; Stoe & Cie, 2002 ▶) T _min = 0.966, T _max = 0.984
27330 measured reflections
2467 independent reflections
2300 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.085
S = 1.06
2467 reflections
262 parameters
H-atom parameters constrained
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2002 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002 ▶); 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 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809009362/hk2636sup1.cif

e-65-0o864-sup1.cif^{(24.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809009362/hk2636Isup2.hkl

e-65-0o864-Isup2.hkl^{(118.8KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7A⋯O2	0.96	2.34	3.002 (3)	125
C12—H12B⋯O4	0.97	2.46	2.899 (2)	107
C15—H15⋯O4ⁱ	0.98	2.53	3.483 (2)	165
C17—H17C⋯O2ⁱⁱ	0.96	2.62	3.533 (3)	158

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors gratefully acknowledge financial support from the Scientific and Technical Research Council of Turkey (TUBITAK, Project No. 107 T676). We also thank the Turkish Grain Board (TMO) for the supply of thebaine.

supplementary crystallographic information

Comment

Morphine alkaloids and related semisynthetic derivatives are the most important groups of non-endogenous opioid-receptor ligands. They can possess both agonist and antagonist properties. Thus, some of them are used as effective analgesics for the treatment of moderate to severe pain or as opioid antagonists for the treatment of narcotic overdosage or opioid addiction; others are used as intermediate products in research (Casy & Parfitt, 1986; Lenz et al., 1986; Schmidhammer, 1998).

Thebaine readily undergoes Diels–Alder reactions with various dienophiles to give the adducts. The diene system of thebaine could potentially be attacked from both faces, but reactions with dienophiles always occur from the same face as the nitrogen bridge (upper face) due to the nitrogen bridge causing the lower face to be hindered through concealment inside a concave system (Maat et al., 1999). The nature of a substituent in positions 7,8 of morphinane alkaloids is among the most important factors affecting their biological activity (Lenz et al., 1986). For instance, the opioid analgesic buprenorphine, ethorphine possesses a pharmacological profile interesting for development of antinarcotics (Lewis, 1985). In view of the importance of the morphine alkaloids, we report herein the crystal structure of the title compound.

In the molecule of the title compound (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. Rings C (C1–C6), D (O2/C5/C6/C11/C15) and E (C4/C5/C8–C11) adopt envelope conformations with C5, C15 and C10 atoms displaced by 0.118 (3), -0.172 (3) and -0.809 (3) Å from the planes of the other ring atoms, respectively. Rings A (N1/C9–C11/C21/C22), B (C10/C12–C14/C19/C20), F (C10–C15) and G (C10/C11/C14/C15/C19/C20) are not planar, having total puckering amplitudes, Q_T, of 0.604 (2), 0.820 (2), 1.047 (2) and 0.942 Å and chair, boat, boat and boat conformations [φ = 78.15 (3) and θ = 9.43 (3)° (for ring A), φ = 3.08 (3) and θ = 87.76 (3)° (for ring B), φ = 155.88 (3) and θ = 152.64 (3)° (for ring F) and φ = -82.44 (3) and θ = 148.46 (3)° (for ring G)] (Cremer & Pople, 1975). The intramolecular C—H···O interactions (Table 1) result in the formations of five- and six-membered rings H (O4/C12/C13/C16/H12B) and I (O1/O2/C1/C6/C7/H7A). Ring H adopts envelope conformation with O4 atom displaced by 0.536 (4) Å from the plane of the other ring atoms, while ring I has twisted conformation. The intramolecular interactions result in the formations of S(5) and S(6) motifs (Bernstein et al., 1995; Etter, 1990) (Fig. 2).

In the crystal structure, weak intermolecular C—H···O hydrogen bonds (Table 1) link the molecules through C(6) and C(8) chains (Bernstein et al., 1995; Etter, 1990) nearly along the [100] and [010] directions (Figs. 2 and 3), generating a three-dimensional network (Fig. 4).

Experimental

The title compound was prepared according to the literature method (Bentley & Hardy, 1967). Thebaine (1.50 g, 4.82 mmol) and methyl acrylate (2.55 ml, 28.3 mmol) were refluxed in benzene (50 ml) for 8 h. After cooling to room temperature, the reaction mixture was concentrated in vacuo. The mixture was centrifuged, and then the title compound was obtained as colorless prisms. It was washed with cold methanol, and recrystallized from methanol.