(1R,4R,5aS,7S,9aS)-7,9a-Dimethyl-6-methyl-ene-3-oxo-1,3,4,5,5a,6,7,8,9,9a-deca-hydro-naphtho-[1,2-c]furan-1,4-diyl diacetate.

The title compound, C(19)H(24)O(6), is a sesquiterpene lactone isolated from the Kenyan plant Warburgia ugandensis. Ring A adopts a chair conformation, ring B is in a C(2) twist conformation and the lactone ring is nearly planar with maximum deviation 0.007 (1) Å. The reported absolute configuration is based on that of the similar compound bromo-parasiticolide A and is supported by analysis of Bijvoet differences from light atoms in Mo Kα radiation.

Related literature

For related structures, see: Fukuyama et al. (1975 ▶) (Bromo-parasiticolide A; PARASB); Ikhiri et al. (1995 ▶) (ZOXLIH); Aranda et al. (2001 ▶) (ABUKIR); King et al. (1973 ▶) (PRPRDE); Rossmann & Lipscomb (1958 ▶) (IRSBBZ); Rahbaek et al. (1997 ▶) (NEYKOR), Zhang et al. (2006 ▶) (UCOLAA, UCOKUT); Harinantenaina et al. (2007 ▶) (NIDJUG); McCorkindale et al. (1981 ▶) (PEBRLD); Hayashi et al. (2010 ▶) (VUTCIX). For the absolute configuration of sesquiterpene lactones, see: Fischer et al. (1979 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶). For the absolute configuration from Bijvoet pairs, see: Hooft et al. (2008 ▶). For compounds from Warburgia ugandensis, see: Wube et al. (2005 ▶) and for related compounds, see: Garland (1969 ▶); Kokwaro (1976 ▶).

Experimental

Crystal data

C19H24O6

M = 348.38

Tetragonal,

a = 13.014 (2) Å

c = 21.167 (3) Å

V = 3584.9 (9) Å3

Z = 8

Mo Kα radiation

μ = 0.10 mm−1

T = 100 K

0.37 × 0.25 × 0.25 mm

Data collection

Nonius KappaCCD diffractometer

Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997 ▶) T min = 0.966, T max = 0.977

11378 measured reflections

6507 independent reflections

5934 reflections with I > 2σ(I)

R int = 0.021

Refinement

R[F 2 > 2σ(F 2)] = 0.036

wR(F 2) = 0.092

S = 1.02

6507 reflections

231 parameters

H-atom parameters constrained

Δρmax = 0.28 e Å−3

Δρmin = −0.21 e Å−3

Absolute structure: Flack (1983 ▶). 2776 Bijvoet pairs

Flack parameter: 0.4 (6)

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); 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 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812033636/bt5979sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033636/bt5979Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812033636/bt5979Isup3.cml

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

C19H24O6	Dx = 1.291 Mg m−3
Mr = 348.38	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P43212	Cell parameters from 6310 reflections
Hall symbol: P 4nw 2abw	θ = 2.5–32.6°
a = 13.014 (2) Å	µ = 0.10 mm−1
c = 21.167 (3) Å	T = 100 K
V = 3584.9 (9) Å3	Prism, colorless
Z = 8	0.37 × 0.25 × 0.25 mm
F(000) = 1488

Nonius KappaCCD diffractometer	6507 independent reflections
Radiation source: sealed tube	5934 reflections with I > 2σ(I)
Horizonally mounted graphite crystal monochromator	Rint = 0.021
Detector resolution: 9 pixels mm-1	θmax = 32.6°, θmin = 3.1°
φ and ω scans	h = −19→19
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	k = −13→13
Tmin = 0.966, Tmax = 0.977	l = −30→31
11378 measured reflections

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.036	H-atom parameters constrained
wR(F2) = 0.092	w = 1/[σ2(Fo2) + (0.0489P)2 + 0.548P] where P = (Fo2 + 2Fc2)/3
S = 1.02	(Δ/σ)max = 0.001
6507 reflections	Δρmax = 0.28 e Å−3
231 parameters	Δρmin = −0.21 e Å−3
0 restraints	Absolute structure: Flack (1983). 2776 Bijvoet pairs
0 constraints	Flack parameter: 0.4 (6)
Primary atom site location: structure-invariant direct methods

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.

	x	y	z	Uiso*/Ueq
C1	0.99387 (7)	0.15194 (7)	0.38460 (4)	0.01487 (16)
C2	1.10097 (8)	0.17487 (8)	0.41219 (5)	0.01852 (17)
H2A	1.1216	0.2454	0.4001	0.022*
H2B	1.0972	0.172	0.4589	0.022*
C3	1.18311 (8)	0.09896 (9)	0.38923 (5)	0.02218 (19)
H3A	1.2483	0.1131	0.4117	0.027*
H3B	1.1952	0.11	0.3436	0.027*
C4	1.15268 (8)	−0.01396 (8)	0.40011 (5)	0.02003 (18)
H4	1.1451	−0.0238	0.4467	0.024*
C5	1.04822 (8)	−0.03292 (8)	0.37083 (4)	0.01737 (17)
C6	0.96687 (7)	0.03709 (7)	0.39832 (4)	0.01477 (15)
H6	0.9717	0.0288	0.4452	0.018*
C7	0.85545 (7)	0.01232 (8)	0.38106 (4)	0.01717 (17)
H7A	0.8433	−0.0624	0.3855	0.021*
H7B	0.8425	0.0315	0.3365	0.021*
C8	0.78177 (8)	0.07130 (7)	0.42426 (4)	0.01629 (17)
H8	0.711	0.0714	0.4058	0.02*
C9	0.81884 (7)	0.17881 (7)	0.43274 (4)	0.01617 (16)
C10	0.75719 (8)	0.26445 (8)	0.45837 (5)	0.01949 (18)
C11	0.91383 (8)	0.32891 (8)	0.42864 (5)	0.01760 (17)
H11	0.9261	0.3685	0.3889	0.021*
C12	0.91114 (7)	0.21474 (7)	0.41591 (4)	0.01502 (16)
C13	0.99210 (8)	0.17746 (8)	0.31324 (4)	0.02007 (18)
H13A	0.9224	0.1675	0.2967	0.03*
H13B	1.0398	0.1319	0.2908	0.03*
H13C	1.013	0.2491	0.3069	0.03*
C14	1.23690 (9)	−0.08734 (10)	0.37789 (6)	0.0301 (2)
H14A	1.216	−0.1583	0.3865	0.045*
H14B	1.3008	−0.0722	0.4005	0.045*
H14C	1.2478	−0.0785	0.3324	0.045*
C15	1.02974 (9)	−0.10108 (9)	0.32528 (5)	0.0227 (2)
H15A	0.9625	−0.1076	0.3083	0.027*
H15B	1.0838	−0.1431	0.3098	0.027*
C16	1.02993 (9)	0.44956 (8)	0.47234 (5)	0.02094 (19)
C17	1.10061 (10)	0.46776 (9)	0.52658 (5)	0.0266 (2)
H17A	1.139	0.5315	0.5196	0.04*
H17B	1.1487	0.4101	0.5302	0.04*
H17C	1.0605	0.4736	0.5656	0.04*
C18	0.71756 (8)	−0.05724 (8)	0.49413 (5)	0.02047 (18)
C19	0.72455 (9)	−0.10197 (10)	0.55937 (5)	0.0262 (2)
H19A	0.6552	−0.1138	0.5759	0.039*
H19B	0.7611	−0.054	0.5871	0.039*
H19C	0.7619	−0.1673	0.5577	0.039*
O1	1.00912 (8)	0.50921 (7)	0.43108 (4)	0.0327 (2)
O2	0.98905 (6)	0.35231 (6)	0.47497 (3)	0.01904 (14)
O3	0.81477 (6)	0.35250 (6)	0.45508 (4)	0.02120 (15)
O4	0.67051 (6)	0.26478 (7)	0.47800 (4)	0.02641 (17)
O5	0.78024 (6)	0.02495 (6)	0.48730 (3)	0.01794 (14)
O6	0.66441 (8)	−0.09022 (8)	0.45248 (4)	0.0323 (2)

	U11	U22	U33	U12	U13	U23
C1	0.0147 (4)	0.0157 (4)	0.0142 (4)	−0.0010 (3)	−0.0002 (3)	0.0010 (3)
C2	0.0154 (4)	0.0190 (4)	0.0212 (4)	−0.0020 (3)	−0.0014 (3)	−0.0006 (4)
C3	0.0148 (4)	0.0253 (5)	0.0265 (5)	0.0002 (4)	0.0006 (4)	−0.0006 (4)
C4	0.0184 (4)	0.0222 (5)	0.0195 (4)	0.0046 (3)	0.0007 (3)	−0.0013 (3)
C5	0.0191 (4)	0.0171 (4)	0.0159 (4)	0.0011 (3)	0.0017 (3)	0.0018 (3)
C6	0.0154 (4)	0.0153 (4)	0.0137 (4)	−0.0006 (3)	0.0001 (3)	0.0005 (3)
C7	0.0178 (4)	0.0176 (4)	0.0161 (4)	−0.0031 (3)	−0.0002 (3)	−0.0014 (3)
C8	0.0149 (4)	0.0186 (4)	0.0154 (4)	−0.0019 (3)	−0.0008 (3)	0.0012 (3)
C9	0.0158 (4)	0.0168 (4)	0.0160 (4)	0.0010 (3)	−0.0007 (3)	−0.0002 (3)
C10	0.0187 (4)	0.0206 (4)	0.0192 (4)	0.0020 (3)	−0.0018 (3)	−0.0011 (3)
C11	0.0185 (4)	0.0165 (4)	0.0178 (4)	0.0004 (3)	−0.0019 (3)	0.0008 (3)
C12	0.0162 (4)	0.0152 (4)	0.0137 (4)	0.0005 (3)	−0.0020 (3)	0.0008 (3)
C13	0.0241 (5)	0.0214 (4)	0.0147 (4)	−0.0002 (4)	0.0017 (3)	0.0038 (3)
C14	0.0222 (5)	0.0337 (6)	0.0342 (6)	0.0087 (4)	0.0005 (4)	−0.0060 (5)
C15	0.0255 (5)	0.0218 (5)	0.0208 (4)	0.0002 (4)	0.0027 (4)	−0.0028 (4)
C16	0.0249 (5)	0.0159 (4)	0.0220 (4)	−0.0026 (4)	0.0036 (4)	−0.0028 (3)
C17	0.0311 (6)	0.0235 (5)	0.0253 (5)	−0.0089 (4)	−0.0024 (4)	−0.0033 (4)
C18	0.0191 (4)	0.0222 (4)	0.0202 (4)	−0.0040 (4)	0.0008 (4)	0.0028 (4)
C19	0.0248 (5)	0.0304 (6)	0.0233 (5)	−0.0026 (4)	−0.0003 (4)	0.0089 (4)
O1	0.0492 (6)	0.0191 (4)	0.0299 (4)	−0.0068 (4)	−0.0052 (4)	0.0050 (3)
O2	0.0226 (4)	0.0154 (3)	0.0191 (3)	−0.0040 (3)	−0.0034 (3)	0.0015 (2)
O3	0.0197 (3)	0.0178 (3)	0.0261 (3)	0.0027 (3)	0.0010 (3)	−0.0020 (3)
O4	0.0181 (3)	0.0295 (4)	0.0316 (4)	0.0029 (3)	0.0022 (3)	−0.0046 (3)
O5	0.0172 (3)	0.0207 (3)	0.0159 (3)	−0.0035 (3)	−0.0009 (2)	0.0027 (3)
O6	0.0364 (5)	0.0361 (5)	0.0243 (4)	−0.0189 (4)	−0.0047 (4)	0.0026 (3)

C1—C12	1.5054 (14)	C10—O3	1.3709 (13)
C1—C2	1.5403 (14)	C11—O2	1.4187 (12)
C1—C13	1.5468 (13)	C11—O3	1.4386 (13)
C1—C6	1.5627 (13)	C11—C12	1.5104 (14)
C2—C3	1.5346 (15)	C11—H11	1
C2—H2A	0.99	C13—H13A	0.98
C2—H2B	0.99	C13—H13B	0.98
C3—C4	1.5393 (16)	C13—H13C	0.98
C3—H3A	0.99	C14—H14A	0.98
C3—H3B	0.99	C14—H14B	0.98
C4—C5	1.5143 (14)	C14—H14C	0.98
C4—C14	1.5279 (15)	C15—H15A	0.95
C4—H4	1	C15—H15B	0.95
C5—C15	1.3321 (14)	C16—O1	1.1994 (14)
C5—C6	1.5131 (13)	C16—O2	1.3740 (12)
C6—C7	1.5297 (14)	C16—C17	1.4902 (15)
C6—H6	1	C17—H17A	0.98
C7—C8	1.5313 (14)	C17—H17B	0.98
C7—H7A	0.99	C17—H17C	0.98
C7—H7B	0.99	C18—O6	1.2000 (13)
C8—O5	1.4646 (12)	C18—O5	1.3529 (12)
C8—C9	1.4908 (14)	C18—C19	1.5013 (15)
C8—H8	1	C19—H19A	0.98
C9—C12	1.3373 (14)	C19—H19B	0.98
C9—C10	1.4766 (14)	C19—H19C	0.98
C10—O4	1.2021 (13)
C12—C1—C2	112.03 (8)	O4—C10—O3	121.84 (10)
C12—C1—C13	107.62 (8)	O4—C10—C9	129.76 (10)
C2—C1—C13	110.01 (8)	O3—C10—C9	108.37 (8)
C12—C1—C6	106.06 (7)	O2—C11—O3	107.67 (8)
C2—C1—C6	108.56 (8)	O2—C11—C12	110.52 (8)
C13—C1—C6	112.55 (8)	O3—C11—C12	104.98 (8)
C3—C2—C1	112.68 (8)	O2—C11—H11	111.1
C3—C2—H2A	109.1	O3—C11—H11	111.1
C1—C2—H2A	109.1	C12—C11—H11	111.1
C3—C2—H2B	109.1	C9—C12—C1	124.74 (9)
C1—C2—H2B	109.1	C9—C12—C11	108.49 (9)
H2A—C2—H2B	107.8	C1—C12—C11	126.58 (9)
C2—C3—C4	112.83 (8)	C1—C13—H13A	109.5
C2—C3—H3A	109	C1—C13—H13B	109.5
C4—C3—H3A	109	H13A—C13—H13B	109.5
C2—C3—H3B	109	C1—C13—H13C	109.5
C4—C3—H3B	109	H13A—C13—H13C	109.5
H3A—C3—H3B	107.8	H13B—C13—H13C	109.5
C5—C4—C14	114.59 (9)	C4—C14—H14A	109.5
C5—C4—C3	108.98 (8)	C4—C14—H14B	109.5
C14—C4—C3	111.47 (9)	H14A—C14—H14B	109.5
C5—C4—H4	107.1	C4—C14—H14C	109.5
C14—C4—H4	107.1	H14A—C14—H14C	109.5
C3—C4—H4	107.1	H14B—C14—H14C	109.5
C15—C5—C6	123.58 (9)	C5—C15—H15A	120
C15—C5—C4	124.53 (9)	C5—C15—H15B	120
C6—C5—C4	111.88 (8)	H15A—C15—H15B	120
C5—C6—C7	116.39 (8)	O1—C16—O2	122.57 (10)
C5—C6—C1	110.31 (8)	O1—C16—C17	126.69 (10)
C7—C6—C1	111.73 (8)	O2—C16—C17	110.74 (9)
C5—C6—H6	105.9	C16—C17—H17A	109.5
C7—C6—H6	105.9	C16—C17—H17B	109.5
C1—C6—H6	105.9	H17A—C17—H17B	109.5
C6—C7—C8	110.20 (8)	C16—C17—H17C	109.5
C6—C7—H7A	109.6	H17A—C17—H17C	109.5
C8—C7—H7A	109.6	H17B—C17—H17C	109.5
C6—C7—H7B	109.6	O6—C18—O5	123.49 (10)
C8—C7—H7B	109.6	O6—C18—C19	124.89 (10)
H7A—C7—H7B	108.1	O5—C18—C19	111.61 (9)
O5—C8—C9	106.34 (7)	C18—C19—H19A	109.5
O5—C8—C7	110.25 (8)	C18—C19—H19B	109.5
C9—C8—C7	109.86 (8)	H19A—C19—H19B	109.5
O5—C8—H8	110.1	C18—C19—H19C	109.5
C9—C8—H8	110.1	H19A—C19—H19C	109.5
C7—C8—H8	110.1	H19B—C19—H19C	109.5
C12—C9—C10	108.79 (9)	C16—O2—C11	115.91 (8)
C12—C9—C8	125.92 (9)	C10—O3—C11	109.35 (8)
C10—C9—C8	125.23 (9)	C18—O5—C8	115.54 (8)
C12—C1—C2—C3	170.06 (8)	C8—C9—C10—O4	1.98 (17)
C13—C1—C2—C3	−70.28 (11)	C12—C9—C10—O3	1.20 (11)
C6—C1—C2—C3	53.28 (10)	C8—C9—C10—O3	−176.04 (9)
C1—C2—C3—C4	−53.11 (12)	C10—C9—C12—C1	−176.62 (8)
C2—C3—C4—C5	53.61 (11)	C8—C9—C12—C1	0.59 (15)
C2—C3—C4—C14	−178.93 (9)	C10—C9—C12—C11	−1.26 (10)
C14—C4—C5—C15	−5.67 (16)	C8—C9—C12—C11	175.95 (9)
C3—C4—C5—C15	120.00 (11)	C2—C1—C12—C9	−137.96 (10)
C14—C4—C5—C6	175.82 (9)	C13—C1—C12—C9	100.99 (11)
C3—C4—C5—C6	−58.51 (10)	C6—C1—C12—C9	−19.68 (12)
C15—C5—C6—C7	11.94 (14)	C2—C1—C12—C11	47.52 (12)
C4—C5—C6—C7	−169.54 (8)	C13—C1—C12—C11	−73.53 (11)
C15—C5—C6—C1	−116.70 (11)	C6—C1—C12—C11	165.80 (8)
C4—C5—C6—C1	61.83 (10)	O2—C11—C12—C9	116.73 (9)
C12—C1—C6—C5	−177.79 (7)	O3—C11—C12—C9	0.90 (10)
C2—C1—C6—C5	−57.24 (9)	O2—C11—C12—C1	−68.02 (12)
C13—C1—C6—C5	64.78 (10)	O3—C11—C12—C1	176.15 (8)
C12—C1—C6—C7	51.08 (9)	O1—C16—O2—C11	−4.93 (15)
C2—C1—C6—C7	171.64 (8)	C17—C16—O2—C11	174.94 (9)
C13—C1—C6—C7	−66.34 (10)	O3—C11—O2—C16	−92.25 (10)
C5—C6—C7—C8	166.12 (8)	C12—C11—O2—C16	153.62 (8)
C1—C6—C7—C8	−65.93 (10)	O4—C10—O3—C11	−178.80 (10)
C6—C7—C8—O5	−74.35 (10)	C9—C10—O3—C11	−0.60 (11)
C6—C7—C8—C9	42.52 (10)	O2—C11—O3—C10	−117.91 (9)
O5—C8—C9—C12	107.52 (10)	C12—C11—O3—C10	−0.14 (10)
C7—C8—C9—C12	−11.78 (13)	O6—C18—O5—C8	−1.47 (15)
O5—C8—C9—C10	−75.71 (11)	C19—C18—O5—C8	177.62 (9)
C7—C8—C9—C10	164.99 (9)	C9—C8—O5—C18	158.03 (8)
C12—C9—C10—O4	179.22 (11)	C7—C8—O5—C18	−82.93 (10)