Methyl 2-(1a,4a-dimethyl-2,8-dioxo-2,3,4,4a,5,6,7,8-octa­hydro-1aH-1-oxacyclo­propa[d]naphthalen-7-yl)acrylate

Mohamed Tebbaa; Ahmed Benharref; Jean Claude Daran; Fouad Mellouki; Moha Berraho

doi:10.1107/S1600536812000086

. 2012 Jan 14;68(Pt 2):o387. doi: 10.1107/S1600536812000086

Methyl 2-(1a,4a-dimethyl-2,8-dioxo-2,3,4,4a,5,6,7,8-octahydro-1aH-1-oxacyclopropa[d]naphthalen-7-yl)acrylate

Mohamed Tebbaa ^a, Ahmed Benharref ^a, Jean Claude Daran ^b, Fouad Mellouki ^a,^*, Moha Berraho ^a

PMCID: PMC3275064 PMID: 22347009

Abstract

The title compound, C₁₆H₂₀O₅, was synthesized from ilicic acid [2-(8-hydroxy-4a,8-dimethyldecahydronaphthalen-2-yl)acrylic acid], which was isolated from the chloroform extract of the aerial part of Inula viscose (L) Aiton [or Dittrichia viscosa (L) Greuter]. The molecule is built up from two fused six-membered rings, the epoxidized six-membered ring adopts a half-chair conformation while the other ring displays a perfect chair conformation. The crystal structure features C—H⋯O hydrogen bonds.

Related literature

For medicinal background to Inula Viscosa (L) Aiton [or Dittrichia Viscosa (L) Greuter], see: Shtacher & Kasshman (1970 ▶); Chiappini et al. (1982 ▶); Azoulay et al. (1986 ▶); Bohlman et al. (1977 ▶); Ceccherelli et al. (1988 ▶); Geissman & Toribio (1967 ▶) For the synthesis, see: Barrero et al. (2009 ▶); Tebbaa et al. (2011 ▶). For conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₆H₂₀O₅
M _r = 292.32
Orthorhombic,
a = 8.8626 (3) Å
b = 9.4552 (3) Å
c = 17.4080 (5) Å
V = 1458.75 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 180 K
0.45 × 0.33 × 0.12 mm

Data collection

Oxford Diffraction Xcalibur Sapphire1 long nozzle diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 ▶) T _min = 0.650, T _max = 1.000
33985 measured reflections
1716 independent reflections
1638 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.028
wR(F ²) = 0.075
S = 1.06
1716 reflections
193 parameters
H-atom parameters constrained
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812000086/bt5772sup1.cif

e-68-0o387-sup1.cif^{(18.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812000086/bt5772Isup2.hkl

e-68-0o387-Isup2.hkl^{(82.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812000086/bt5772Isup3.cml

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
C3—H3A⋯O5ⁱ	0.97	2.57	3.492 (2)	158
C5—H5A⋯O4ⁱⁱ	0.97	2.50	3.337 (2)	145
C7—H7⋯O3ⁱⁱ	0.98	2.54	3.3321 (19)	138
C7—H7⋯O4ⁱⁱ	0.98	2.54	3.3877 (19)	145

Open in a new tab

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

supplementary crystallographic information

Comment

Our work lies within the framework of the evaluation of medicinals plants and in particular, Inula Viscosa (L) Aiton or Dittrichia Viscosa (L) Greuter]. This plant is widespread in Mediterranean area and extends to the Atlantic cost of Morocco. It is a well known medicinal plant (Shtacher & Kasshman, 1970; Chiappini et al., 1982) and has some pharmacological activities (Azoulay et al., 1986). This plant has been the subject of chemical investigation in terms of isolating sesquiterpene lactones (Bohlman et al., 1977), sesquiterpene acids (Ceccherelli et al., 1988; Geissman & Toribio, 1967). The ilicic acid is one of the main components of the dichloromethane extract of the Inula Viscosa (L) Aiton or Dittrichia Viscosa (L) Greuter]. The literature reports one article on the transformation of the ilicic acid (Barrero et al., 2009). In order to prepare products with high added value, that can be used in the pharmacologycal industry, we have studied the reactivity of this sesquiterpene acid. Thus, from this acid, we have prepared by the method of Barrero et al. (2009), 2-(4a,8-Dimethyl-1, 2,3,4,4 a,5,6,7-octahydro naphthalen-2-yl)-acrylic acid methyl ester(1) (Figure 3). The epoxidation of this sesquiterpene by metachloroperbenzoic acid (mCPBA), followed by the opening of the epoxide, obtained by Bi(OTf)₃ (Tebbaa et al., 2011), leads to the compound (2) with a yield of 40%. The oxidation of the latter with chromic anhydride (CrO₃) leads to the title compound with a yield of 60%. The crystal structure of the title compound is escribed herein. The molecule is built up from two fused six-membered rings. The molecular structure (Fig. 1), shows that the two rings adopt different conformations. A perfect chair conformation for the first ring (C1, C4a···C8) as indicated by Cremer & Pople (1975) puckering parameters Q(T)= 0.5561 (19)Å and spherical polar angle θ = 178.35 (18)° with φ = 245 (6)°. While the second ring (C1, C4a···C1a) displays a half chair conformation with Q(T) = 0.4303 (19), θ = 47,5(2)° and φ = 225,8(3). The crystal structure is stabilized by intermolecular C—H···O hydrogen bonds. (Table 1, Figure 2).

Experimental

To a solution of 1 g (4 mmol) of 2-(4a,8-Dimethyl-2, 3,4,4a,5,6- hexahydro-naphthalene-2-yl)-acrylic acid methyl ester (2) dissolved in 20 ml acetone is added in small portions three equivalents of chromic anhydride (CrO₃) at 0° C. The reaction mixture is left stirring for 1 h, then treated with 20 ml of cold water and extracted three times with 30 ml of ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated under reduced pressure. The residue obtained is chromatographed on silica gel eluting with hexane-ethyl acetate (98–2) allowed the isolation in pure the 2 - (1a, 4a-dimethyl-2, 8 -dioxo- octahydro-1-oxa-cycloprop [d] naphthalene-7-yl)-acrylic acid methyl, with a yield of 60% (70 mg, 2.4 mmol). The title compound was recrystallized from its dichloromethane solution at room temperature.