(1R,4R,5aS,7S,9aS)-7,9a-Dimethyl-6-methyl­ene-3-oxo-1,3,4,5,5a,6,7,8,9,9a-deca­hydro­naphtho­[1,2-c]furan-1,4-diyl diacetate

The title compound, C₁₉H₂₄O₆, is a sesquiterpene lactone isolated from the Kenyan plant Warburgia ugandensis. Ring A adopts a chair conformation, ring B is in a C₂ 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 K[alpha] radiation.

Key indicators

• Single-crystal X-ray study
• T = 100 K, P = 0.0 kPa
• Mean [sigma](C-C) = 0.001 Å
• R factor = 0.036
• wR factor = 0.092
• Data-to-parameter ratio = 28.2

checkCIF/PLATON results

No syntax errors found



Alert level C
STRVA01_ALERT_4_C           Flack test results are ambiguous.
           From the CIF: _refine_ls_abs_structure_Flack    0.400
           From the CIF: _refine_ls_abs_structure_Flack_su    0.600
PLAT033_ALERT_4_C Flack x Parameter Value Deviates from Zero .....      0.400
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          5

Alert level G
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
           From the CIF: _diffrn_reflns_theta_max           32.56
           From the CIF: _reflns_number_total               6507
           From the CIF: _diffrn_reflns_limit_ max hkl   19.   13.   31.
           From the CIF: _diffrn_reflns_limit_ min hkl  -19.  -13.  -30.
           TEST1: Expected hkl limits for theta max
           Calculated maximum hkl   19.   19.   32.
           Calculated minimum hkl  -19.  -19.  -32.
REFLT03_ALERT_4_G  ALERT: MoKa measured Friedel data cannot be used to
                   determine absolute structure in a light-atom
                   study EXCEPT under VERY special conditions.
                   It is preferred that Friedel data is merged in such cases.
           From the CIF: _diffrn_reflns_theta_max           32.56
           From the CIF: _reflns_number_total               6507
           Count of symmetry unique reflns         3745
           Completeness (_total/calc)            173.75%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      2762
           Fraction of Friedel pairs measured     0.738
           Are heavy atom types Z>Si present         no
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT032_ALERT_4_G Std. Uncertainty on Flack Parameter Value High .      0.600
PLAT152_ALERT_1_G The Supplied and Calc. Volume s.u. Differ by ...          3 Units
PLAT791_ALERT_4_G Note: The Model has Chirality at C1     (Verify)          S
PLAT791_ALERT_4_G Note: The Model has Chirality at C4     (Verify)          S
PLAT791_ALERT_4_G Note: The Model has Chirality at C6     (Verify)          S
PLAT791_ALERT_4_G Note: The Model has Chirality at C8     (Verify)          R
PLAT791_ALERT_4_G Note: The Model has Chirality at C11    (Verify)          R
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          9
PLAT916_ALERT_2_G Hooft y and Flack x Parameter values differ by .       0.30
PLAT951_ALERT_5_G Reported and Calculated Kmax Values Differ by ..          6

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   3 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  13 ALERT level G = General information/check it is not something unexpected

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
  10 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

---

S1. Comment

Coloratanolide and drimanolide sesquiterpene lactones, such as title compound I, have been isolated from the stem bark of Warburgia ugandensis Sprague (Canellaceae) as described by Wube et al. (2005). Plants of the genus Warburgia are of interest because of their use by herbalists in Kenya for the treatment of a number of parasitic diseases (Kokwaro, 1976). Compound I is the first sesquiterpene lactone to be crystallographically characterized which has the coloratanolide skeleton, (CAS 60306–54-9). The absolute configuration reported herein is based on the configuration of bromo-parasiticolide A (Fukuyama et al., 1975), CCDC refcode PARASB (Allen, 2002), and supported by analysis of 2776 Bijvoet pairs.

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 elated compounds, see: Garland (1969); Kokwaro (1976).

S2. Experimental

Compound I was isolated from the stem bark of Warburgia ugandensis Sprague (Canellaceae) collected in Eldoret, Uasin Gishu District, Kenya. Crystals suitable for diffraction were grown from acetone/hexane/ethyl ether.

S3. Refinement

H atoms were placed in calculated positions, guided by difference maps, with C—H bond distances 0.95–1.00 Å, U_iso = 1.2U_eq of the attached carbon atom (1.5 for methyl), and thereafter treated as riding. A torsional parameter was refined for each methyl group.

The absolute configuration and space group assignment were established in part by analysis of 2776 Bijvoet pairs. Although the refined Flack parameter x = 0.4 (6) (Flack, 1983) is not definitive, the Hooft parameter y = 0.1 (3) and Hooft P2(true) = 0.998 (Hooft et al., 2008) are strong indicators that the reported configuration is correct. This configuration is consistent with that of bromo-parasiticolide A (Fukuyama et al., 1975), CCDC refcode PARASB (Allen, 2002) and with the accepted configuration of sesquiterpene lactones from higher plants (Fischer et al., 1979).

Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); 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).

Figures

Fig. 1. View of (I) (50% probability displacement ellipsoids)

(1R,4R,5aS,7S,9aS)-7,9a-Dimethyl- 6-methylene-3-oxo-1,3,4,5,5a,6,7,8,9,9a- decahydronaphtho[1,2-c]furan-1,4-diyl diacetate

Crystal data

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) Å^3	Prism, colorless
Z = 8	0.37 × 0.25 × 0.25 mm
F(000) = 1488

Data collection

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

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.036	H-atom parameters constrained
wR(F^2) = 0.092	w = 1/[σ^2(Fo^2) + (0.0489P)^2 + 0.548P] where P = (Fo^2 + 2Fc^2)/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	Absolute structure parameter: 0.4 (6)
Primary atom site location: structure-invariant direct methods

Special details

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 (Ų)

	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)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
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)

Geometric parameters (Å, º)

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)