Methyl 2-(1a,4a-dimethyl-2,8-dioxo-2,3,4,4a,5,6,7,8-octa-hydro-1aH-1-oxacyclo-propa[d]naphthalen-7-yl)acrylate.

The title compound, C(16)H(20)O(5), was synthesized from ilicic acid [2-(8-hy-droxy-4a,8-dimethyl-deca-hydro-naphthalen-2-yl)acrylic acid], which was isolated from the chloro-form 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 = 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

Δρmax = 0.20 e Å−3

Δρmin = −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 ▶).

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

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

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

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

C16H20O5	F(000) = 624
Mr = 292.32	Dx = 1.331 Mg m−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 33985 reflections
a = 8.8626 (3) Å	θ = 3.2–26.4°
b = 9.4552 (3) Å	µ = 0.10 mm−1
c = 17.4080 (5) Å	T = 180 K
V = 1458.75 (8) Å3	Prism, colourless
Z = 4	0.45 × 0.33 × 0.12 mm

Oxford Diffraction Xcalibur Sapphire1 long nozzle diffractometer	1716 independent reflections
Radiation source: fine-focus sealed tube	1638 reflections with I > 2σ(I)
graphite	Rint = 0.040
Detector resolution: 8.2632 pixels mm-1	θmax = 26.4°, θmin = 3.2°
ω scans	h = −11→11
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)	k = −11→11
Tmin = 0.650, Tmax = 1.000	l = −21→21
33985 measured reflections

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.075	H-atom parameters constrained
S = 1.06	w = 1/[σ2(Fo2) + (0.0462P)2 + 0.2444P] where P = (Fo2 + 2Fc2)/3
1716 reflections	(Δ/σ)max < 0.001
193 parameters	Δρmax = 0.20 e Å−3
0 restraints	Δρmin = −0.15 e Å−3

Experimental. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. CrysAlisPro (Oxford Diffraction, 2010)

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.

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 > 2σ(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
C1	−0.13339 (18)	0.03809 (16)	0.70987 (9)	0.0207 (3)
C1A	−0.05450 (19)	0.08964 (18)	0.64052 (9)	0.0239 (3)
C2	−0.1449 (2)	0.1740 (2)	0.58274 (10)	0.0299 (4)
C3	−0.2984 (2)	0.2227 (2)	0.60642 (10)	0.0330 (4)
H3A	−0.3578	0.2417	0.5607	0.040*
H3B	−0.2889	0.3106	0.6347	0.040*
C4	−0.3818 (2)	0.1157 (2)	0.65598 (10)	0.0304 (4)
H4A	−0.4002	0.0313	0.6257	0.036*
H4B	−0.4790	0.1549	0.6702	0.036*
C4A	−0.29707 (17)	0.07384 (17)	0.72924 (9)	0.0220 (3)
C5	−0.29623 (18)	0.19549 (17)	0.78766 (9)	0.0233 (3)
H5A	−0.2565	0.2797	0.7631	0.028*
H5B	−0.3992	0.2154	0.8031	0.028*
C6	−0.20299 (18)	0.16391 (19)	0.85886 (9)	0.0244 (4)
H6A	−0.2494	0.0868	0.8870	0.029*
H6B	−0.2025	0.2465	0.8919	0.029*
C7	−0.03943 (17)	0.12379 (16)	0.83876 (8)	0.0194 (3)
H7	0.0067	0.2064	0.8142	0.023*
C8	−0.04044 (17)	0.00594 (16)	0.78003 (9)	0.0204 (3)
C9	0.05601 (18)	0.08709 (18)	0.90730 (9)	0.0224 (3)
C10	0.22089 (18)	0.10826 (18)	0.89680 (9)	0.0221 (3)
C11	0.0043 (2)	0.0305 (3)	0.97121 (11)	0.0409 (5)
H11A	0.0709	0.0037	1.0098	0.049*
H11B	−0.0989	0.0173	0.9777	0.049*
C12	0.1137 (2)	0.1040 (2)	0.63642 (10)	0.0322 (4)
H12A	0.1479	0.0766	0.5863	0.048*
H12B	0.1594	0.0442	0.6744	0.048*
H12C	0.1415	0.2006	0.6460	0.048*
C13	−0.3722 (2)	−0.05753 (19)	0.76273 (11)	0.0314 (4)
H13A	−0.3246	−0.0817	0.8105	0.047*
H13B	−0.3620	−0.1348	0.7273	0.047*
H13C	−0.4773	−0.0388	0.7715	0.047*
C14	0.4577 (2)	0.1183 (3)	0.95628 (11)	0.0376 (5)
H14A	0.4832	0.2048	0.9305	0.056*
H14B	0.4952	0.0395	0.9272	0.056*
H14C	0.5025	0.1178	1.0065	0.056*
O1	0.29605 (13)	0.10753 (16)	0.96328 (7)	0.0318 (3)
O2	0.28032 (14)	0.12332 (15)	0.83537 (7)	0.0307 (3)
O3	−0.11162 (14)	−0.05477 (12)	0.64566 (6)	0.0263 (3)
O4	0.02356 (14)	−0.10571 (13)	0.78860 (7)	0.0298 (3)
O5	−0.09164 (19)	0.19766 (18)	0.52039 (8)	0.0492 (4)

	U11	U22	U33	U12	U13	U23
C1	0.0221 (8)	0.0195 (7)	0.0205 (7)	0.0005 (6)	0.0014 (6)	−0.0044 (6)
C1A	0.0274 (8)	0.0231 (8)	0.0211 (7)	0.0002 (7)	0.0024 (6)	−0.0017 (6)
C2	0.0388 (10)	0.0275 (8)	0.0235 (8)	0.0001 (8)	−0.0015 (7)	0.0006 (7)
C3	0.0358 (10)	0.0372 (10)	0.0261 (8)	0.0086 (9)	−0.0073 (8)	0.0024 (8)
C4	0.0239 (8)	0.0380 (10)	0.0293 (8)	0.0020 (8)	−0.0073 (7)	−0.0046 (8)
C4A	0.0181 (7)	0.0245 (8)	0.0234 (7)	0.0004 (6)	−0.0007 (6)	−0.0025 (7)
C5	0.0192 (7)	0.0251 (8)	0.0255 (7)	0.0042 (6)	0.0000 (6)	−0.0029 (7)
C6	0.0205 (8)	0.0291 (9)	0.0235 (8)	0.0042 (7)	0.0015 (7)	−0.0052 (7)
C7	0.0184 (7)	0.0201 (7)	0.0198 (7)	0.0001 (6)	0.0003 (6)	0.0001 (6)
C8	0.0161 (7)	0.0225 (7)	0.0226 (7)	−0.0004 (6)	0.0049 (6)	0.0004 (6)
C9	0.0212 (8)	0.0242 (8)	0.0218 (7)	0.0006 (7)	0.0005 (6)	−0.0003 (6)
C10	0.0215 (8)	0.0232 (8)	0.0215 (7)	0.0022 (7)	−0.0012 (6)	0.0009 (7)
C11	0.0256 (9)	0.0678 (14)	0.0294 (9)	−0.0027 (9)	−0.0007 (8)	0.0167 (10)
C12	0.0284 (9)	0.0370 (10)	0.0314 (8)	−0.0018 (9)	0.0083 (7)	−0.0012 (8)
C13	0.0262 (9)	0.0300 (9)	0.0379 (9)	−0.0058 (8)	0.0026 (8)	−0.0030 (8)
C14	0.0194 (8)	0.0599 (12)	0.0336 (9)	−0.0015 (9)	−0.0043 (7)	0.0025 (10)
O1	0.0201 (6)	0.0533 (8)	0.0221 (6)	−0.0018 (6)	−0.0024 (5)	0.0008 (6)
O2	0.0256 (6)	0.0437 (8)	0.0226 (6)	0.0003 (6)	0.0034 (5)	0.0049 (6)
O3	0.0327 (6)	0.0227 (6)	0.0235 (6)	0.0004 (5)	0.0021 (5)	−0.0059 (5)
O4	0.0329 (6)	0.0234 (6)	0.0331 (6)	0.0086 (5)	−0.0033 (5)	−0.0013 (5)
O5	0.0603 (9)	0.0587 (10)	0.0286 (7)	0.0110 (8)	0.0104 (7)	0.0139 (7)

C1—O3	1.4344 (19)	C6—H6B	0.9700
C1—C1A	1.478 (2)	C7—C9	1.503 (2)
C1—C8	1.504 (2)	C7—C8	1.512 (2)
C1—C4A	1.527 (2)	C7—H7	0.9800
C1A—O3	1.459 (2)	C8—O4	1.208 (2)
C1A—C12	1.499 (2)	C9—C11	1.317 (2)
C1A—C2	1.513 (2)	C9—C10	1.486 (2)
C2—O5	1.204 (2)	C10—O2	1.2005 (19)
C2—C3	1.495 (3)	C10—O1	1.3354 (19)
C3—C4	1.521 (3)	C11—H11A	0.9300
C3—H3A	0.9700	C11—H11B	0.9300
C3—H3B	0.9700	C12—H12A	0.9600
C4—C4A	1.532 (2)	C12—H12B	0.9600
C4—H4A	0.9700	C12—H12C	0.9600
C4—H4B	0.9700	C13—H13A	0.9600
C4A—C13	1.525 (2)	C13—H13B	0.9600
C4A—C5	1.535 (2)	C13—H13C	0.9600
C5—C6	1.519 (2)	C14—O1	1.442 (2)
C5—H5A	0.9700	C14—H14A	0.9600
C5—H5B	0.9700	C14—H14B	0.9600
C6—C7	1.539 (2)	C14—H14C	0.9600
C6—H6A	0.9700
O3—C1—C1A	60.11 (10)	C5—C6—H6B	109.2
O3—C1—C8	115.80 (13)	C7—C6—H6B	109.2
C1A—C1—C8	118.09 (13)	H6A—C6—H6B	107.9
O3—C1—C4A	115.81 (12)	C9—C7—C8	111.71 (13)
C1A—C1—C4A	123.84 (14)	C9—C7—C6	113.99 (13)
C8—C1—C4A	112.69 (13)	C8—C7—C6	109.26 (12)
O3—C1A—C1	58.47 (10)	C9—C7—H7	107.2
O3—C1A—C12	115.66 (14)	C8—C7—H7	107.2
C1—C1A—C12	122.65 (15)	C6—C7—H7	107.2
O3—C1A—C2	110.53 (14)	O4—C8—C1	122.29 (15)
C1—C1A—C2	117.81 (15)	O4—C8—C7	123.90 (15)
C12—C1A—C2	116.54 (16)	C1—C8—C7	113.78 (13)
O5—C2—C3	123.23 (18)	C11—C9—C10	120.07 (15)
O5—C2—C1A	119.32 (18)	C11—C9—C7	124.64 (15)
C3—C2—C1A	117.45 (15)	C10—C9—C7	115.12 (14)
C2—C3—C4	113.19 (16)	O2—C10—O1	123.63 (15)
C2—C3—H3A	108.9	O2—C10—C9	123.85 (15)
C4—C3—H3A	108.9	O1—C10—C9	112.52 (14)
C2—C3—H3B	108.9	C9—C11—H11A	120.0
C4—C3—H3B	108.9	C9—C11—H11B	120.0
H3A—C3—H3B	107.8	H11A—C11—H11B	120.0
C3—C4—C4A	113.97 (14)	C1A—C12—H12A	109.5
C3—C4—H4A	108.8	C1A—C12—H12B	109.5
C4A—C4—H4A	108.8	H12A—C12—H12B	109.5
C3—C4—H4B	108.8	C1A—C12—H12C	109.5
C4A—C4—H4B	108.8	H12A—C12—H12C	109.5
H4A—C4—H4B	107.7	H12B—C12—H12C	109.5
C13—C4A—C1	108.59 (14)	C4A—C13—H13A	109.5
C13—C4A—C4	108.35 (14)	C4A—C13—H13B	109.5
C1—C4A—C4	109.80 (13)	H13A—C13—H13B	109.5
C13—C4A—C5	111.05 (13)	C4A—C13—H13C	109.5
C1—C4A—C5	107.90 (12)	H13A—C13—H13C	109.5
C4—C4A—C5	111.11 (13)	H13B—C13—H13C	109.5
C6—C5—C4A	113.32 (13)	O1—C14—H14A	109.5
C6—C5—H5A	108.9	O1—C14—H14B	109.5
C4A—C5—H5A	108.9	H14A—C14—H14B	109.5
C6—C5—H5B	108.9	O1—C14—H14C	109.5
C4A—C5—H5B	108.9	H14A—C14—H14C	109.5
H5A—C5—H5B	107.7	H14B—C14—H14C	109.5
C5—C6—C7	112.04 (13)	C10—O1—C14	114.97 (13)
C5—C6—H6A	109.2	C1—O3—C1A	61.42 (10)
C7—C6—H6A	109.2

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

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

Symmetry codes: (i) ; (ii) .