Crystal structure of the monoglycidyl ether of isoeugenol.

The title compound, C13H16O3 [GE-isoEu; systematic name: 2-({2-meth-oxy-4-[(E)-1-propen-1-yl]phen-oxy}meth-yl)oxirane], which crystallizes in the triclinic P space group, was synthesized in one step from iso-eugenol, a bio-based phenyl-propanoid, with an excess of epi-chloro-hydrin. Colourless prismatic crystals suitable for X-ray diffraction were obtained from a mixture of ethyl acetate and cyclo-hexane, during purification by column chromatography on silica gel. GE-isoEu, which corresponds to the trans isomer of the monoglycidyl ether of iso-eugenol, is based on a 1,2,4-tris-ubstituted benzene ring by diglycidyl ether, meth-oxy and 1-(E)-propenyl groups, respectively. In the crystal, mol-ecules are organized through offset π-stacking inter-actions. Chemically, GE-isoEu constitutes an inter-mediate in the synthesis protocol of 2-[3-meth-oxy-4-(2-oxiranylmeth-oxy)phen-yl]-3-methyl-oxirane (GEEp-isoEu), a di-epoxy-dized monomer used in the manufacturing of thermosetting resins and intended for the elaboration of bio-composites. © Cattey et al. 2022.

Chemical context

The bis­phenol A diglycidyl ether mol­ecule, also called BADGE or DGEBA, is the main building block used for the formulation of commercial ep­oxy resins (Mohan, 2013 ▸). Synthetically, this reagent is directly produced from 2,2-bis­(4-hy­droxy­phen­yl)propane (bis­phenol A), derived from petroleum resources (phenol) and recognized as being an endocrine disruptor (Fenichel et al., 2013 ▸). With the aim of designing more sustainable synthetic routes and alternatives to fossil resources, some of the mol­ecules derived from biomass and in particular phenyl­propano­ids isolated from the fragmentation of lignin, are considered as potential building blocks to replace bis­phenol A and its derivatives (Auvergne et al., 2014 ▸). This is particularly the case of the iso-eugenol mol­ecule generally used in the composition of many perfumes and which can be also transformed into a diepoxidized monomer, 2-[3-meth­oxy-4-(2-oxiranylmeth­oxy)phen­yl]-3-methyl­oxirane (GEEp-isoEu), well-suited to ep­oxy thermosetting applications and exhibiting comparable thermomechanical properties to DGEBA (François et al., 2016 ▸, 2017 ▸). The preparation of GEEp-isoEu involves a two-step synthesis via firstly the formation of the title compound as a synthesis inter­mediate. We report herein the X-ray crystal structure of GE-isoEu [systematic name: 2-({2-meth­oxy-4-[(E)-1-propen-1-yl]phen­oxy}meth­yl)oxirane], which crystallizes upon its purification from a mixture of cyclo­hexane and ethyl acetate.

Structural commentary

The title compound exhibits an asymmetrical structure, which is depicted in Fig. 1 ▸. GE-isoEu comprises a benzene ring substituted by two oxygenated functional groups, glycidyl ether [–OCH2C2H3O] and meth­oxy [–OCH3], and one 1-(E)-propenyl side chain [–HC=CHCH3] located in meta and para positions to the meth­oxy and glycidyl ether functions, respectively. The aromatic ring is planar with mean bond lengths and angles of 1.392 (3) Å and 120.13 (17)°. While the –OCH3 and –HC=CHCH3 groups are in the plane of the benzene ring, –C2H3O is out of the plane with an angle of 52.83 (14)°. The oxirane ring (C1/C2/O1) of the glycidyl ether group does not undergo any disorder, in contrast to what is frequently observed for diglycidyl ether derivatives (Cho et al., 1999 ▸; Flippen-Anderson & Gilardi, 1981 ▸). The double-bond distance of the 1-(E)-propenyl side chain was determined as 1.315 (3) Å. This length is consistent with those described in the literature for similar compounds (Stomberg et al., 1993 ▸; Stomberg & Lundquist, 1995 ▸).

Figure 1

The mol­ecular structure of GE-isoEu with displacement ellipsoids at the 30% probability level.

Supra­molecular features

The most significant supra­molecular inter­action observed in the crystal consists of offset π-stacking involving aromatic rings of GE-isoEu (Fig. 2 ▸ – red dotted lines). The inter­planar and the centroid-to-centroid distances between parallel mol­ecules are 3.456 (2) and 4.5931 (5) Å, respectively. The important difference between these two distances indicates that the benzene rings are strongly slipped. The slip angle (angle between the normal to the planes and the centroid–centroid vector) is 41.20° corresponding to a slippage distance of 3.025 (3) Å (these high values can nevertheless be considered as limit values). Typically, for such inter­actions, the inter­planar distance between the arene planes is found around 3.3 to 3.8 Å (Janiak, 2000 ▸). In addition, mol­ecules of GE-isoEu also inter­act in pairs, forming dimers, via non-classical inter­molecular hydrogen bonds involving the methyl groups of the meth­oxy substituents, with the oxygen atoms of the ether [C10—H10A⋯O2 = 3.537 (2) Å, 167°] and meth­oxy functions [C10—H10A⋯O3 = 3.405 (2) Å, 132°] (Fig. 2 ▸ -– blue dotted lines). These supra­molecular inter­actions result in a propagation of stacks of mol­ecules oriented along the a-axis (Fig. 3 ▸).

Figure 2

Mercury representation (Macrae et al., 2020 ▸; colour code: C dark grey, O red; hydrogen atoms are omitted for clarity) showing inter­molecular inter­actions in the crystal structure of the title compound with hydrogen bonding (blue dotted line, C—H⋯O distance) and π–π stacking (red dotted line, centroid–centroid distance).

Figure 3

Stacking representation of GE-isoEu viewed down the a axis (colour code: C dark grey, O red, H white; Mercury representation; Macrae et al., 2020 ▸).

Database survey

A search in the Cambridge Structural Database (WebCSD v1.1.2, update 2022-03-05; Groom et al., 2016 ▸), highlighted that, up to now, seventeen crystal structures comprising glycidyl ether-substituted phenyl ring moieties have been reported. They include (S)-1-(2-chloro-5-methyl­phen­oxy)-2,3-ep­oxy­propane (CIKQIZ: Bredikhin et al., 2018 ▸), 2,2-bis­(3,5-di­bromo-4-hy­droxy­benzene)­propane diglycidyl ether (COMNEX: Saf’yanov et al., 1984 ▸), 2,2-bis­(4-(oxiran-2-ylmeth­oxy)-3,5-di­bromo­phen­yl)propane (COMNEY: Cheban et al., 1985 ▸), rac-1,2-ep­oxy-3-(2-meth­oxy­phen­yloxy)propane (DAXKAP: Bredikhin et al., 2005 ▸), diglycidyl ether of bis­phenol A (DGEBPA: Flippen-Anderson & Gilardi, 1980 ▸; (DGEBPA01: Heinemann et al., 1993 ▸; DGEBPA10: Flippen-Anderson & Gilardi, 1981 ▸), p-di(2,3-ep­oxy­prop­yloxy)benzene (EOXHQE: Saf’yanov et al., 1977 ▸), 2,2′-[1,3-phenyl­ene-bis(oxymethyl­ene)]bis­(oxirane) (FITWOU: Bocelli & Grenier-Loustalot, 1987 ▸), 1,2-ep­oxy-3-(2-cyano­phen­oxy)propane (JESHOF: Bredikhin, et al., 2006 ▸), 2-[(4-{3-[4-(oxiran-2-ylmeth­oxy)phen­yl]tri­cyclo­[3.3.1.13,7]decan-1-yl}phen­oxy)meth­yl]oxirane (LANRUQ: Wang et al., 2017 ▸), 2-(4-{4-[4-(oxiran-2-ylmeth­oxy)phen­oxy]phen­yl}phen­oxy­meth­yl)oxi­rane (LAQTII: Song et al., 2012 ▸), 10-[2,5-bis­(2,3-ep­oxy-1-prop­oxy)phen­yl]-9-oxa-10-phosphaphenanthren-10-one (LIPSOS: Cho et al., 1999 ▸), 3,7-dimeth­oxy-2-[4-meth­oxy-3-(oxiran-2-ylmeth­oxy)phen­yl]-5-(oxiran-2-ylmeth­oxy)-4H-chro­men-4-one (ORASAD: Kristufek et al., 2016 ▸), 2,2′-{methyl­enebis[(2,1-phenyl­ene)oxymethyl­ene]}bis­(oxirane) [PALQUS: Liu et al., 2021 ▸), 2-(N-meth­oxy­ethanimido­yl)-5-(oxiran-2-ylmeth­oxy)benzo­nitrile (SIJZIW: Gong et al., 2013 ▸); 2-({3-meth­oxy-4-[(oxiran-2-yl)meth­oxy]phen­yl}meth­yl)oxi­rane (WASCIF: Vigier et al., 2017 ▸), 4-(oxiran-2-ylmeth­oxy)benzoic acid (ZEPYUQ: Obreza & Perdih, 2012 ▸). To the best of our knowledge, the structure of GE-isoEu based on a benzene ring tri-substituted by glycidyl ether, meth­oxy and 1-propenyl functions is new. In terms of application, several of these compounds are targeted as synthesis inter­mediates or precursors devoted to the formulation of thermosetting resins. The polymerization process involves the ep­oxy rings of mol­ecules and occurs in the presence of hardeners (such as amines or acid anhydrides), leading to the cross-linking of infusible polymer networks.

Synthesis and crystallization

The title compound was prepared in one step from a commercial source of natural isoeugenol (mixture of cis/trans, 99% purity, Sigma-Aldrich) according to a previously reported protocol (François et al., 2016 ▸). The details of the synthesis of the title compound are summarized in Fig. 4 ▸. iso-Eugenol (10.0 g, 60.9 mmol) was added to an ethano­lic sodium hydroxide solution (2.7 g, 66.6 mmol of NaOH in 30 mL of EtOH), then followed by the addition of an excess of epi­chloro­hydrin (19.1 mL, 22.5 g, 243.6 mmol). The reaction mixture was heated at 353 K over 3 h under constant stirring. 70 mL of toluene were then added at room temperature. After cannula filtration, the filtrate was washed with distilled water (3 × 20 mL) and brine (1 × 20 mL), and finally dried over anhydrous MgSO4. After complete evaporation of the solvent under vacuum, the residue was then further purified by column chromatography using a mixture of cyclo­hexa­ne/ethyl acetate (3:1, v/v) as eluent to give a white solid characterized as the monoglycidyl ether of iso-eugenol (6.2 g, yield 46%). Crystals of the trans isomer of GE-isoEu suitable for X-ray analysis were obtained during the purification by column chromatography by evaporation of the eluting solvents at room temperature. 1H NMR (300.1 MHz, CDCl3): 6.90–6.82 (m, 3H, ar­yl), 6.08 (dq, J = 6.6 and 15.7 Hz, 1H, CH-propen­yl), 6.33 (dd, J =1.6 and 15.7 Hz, 1H, CH-propen­yl), 4.21 (dd, J = 11.4 and 3.6 Hz, 1H, CH 2O), 4.03 (dd, J = 11.4 and 5.5 Hz, 1H, CH 2O), 3.88 (s, 3H, OCH 3); 3.38 (m, 1H, CH-oxirane), 2.89 (dd, J = 5.1 and 4.2 Hz, 1H, CH 2 -oxirane), 2.73 (dd, J = 5.0 and 2.7 Hz, 1H, CH 2 -oxirane), δ 1.86 (dd, J = 1.6 and 6.6 Hz, 3H, CH 3); 13C{1H} NMR (75.4 MHz, CDCl3) δ 149.6, 147.1, 132.2, 130.5, 124.2, 118.6, 114.2, 109.1, 70.3, 55.8, 50.2, 45.0, 18.4; IR (ATR): 3023, 3000, 2957, 2937, 2913, 2878, 2842, 1601, 1582, 1509, 1464, 1450, 1419, 1259, 1226, 1195, 1158, 1135, 1024, 961, 908, 857, 805, 778, 759, 734, 621, 612, 569, 464 cm−1. Analysis calculated for C13H16O3: C, 69.67; H, 6.11. Found: C, 70.28; H, 7.57.

Figure 4

Synthesis protocol and reaction conditions leading to GE-isoEu.

Refinement details

Crystal data, data collection and structure refinement details are summarized in Table 1 ▸. All H atoms on carbon and oxygen atoms were placed at calculated positions using a riding model with C—H = 0.95 Å (aromatic) or 0.99 Å (methyl­ene group) with U iso(H) = 1.2U eq and C—H = 0.98 Å (methyl group) with U iso(H) = 1.5U eq(H).

Table 1

Experimental details

Crystal data
Chemical formula	C13H16O3
M r	220.26
Crystal system, space group	Triclinic, P
Temperature (K)	150
a, b, c (Å)	4.5931 (5), 8.9134 (9), 15.0764 (18)
α, β, γ (°)	74.808 (3), 85.309 (4), 77.430 (3)
V (Å3)	581.18 (11)
Z	2
Radiation type	Mo Kα
μ (mm−1)	0.09
Crystal size (mm)	0.5 × 0.15 × 0.15
Data collection
Diffractometer	Bruker Kappa APEXII
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 ▸)
T min, T max	0.668, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	17290, 2647, 1865
R int	0.038
(sin θ/λ)max (Å−1)	0.650
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.049, 0.128, 1.03
No. of reflections	2647
No. of parameters	147
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.33, −0.19

Computer programs: APEX3 (Bruker, 2020 ▸), SAINT (Bruker, 2016 ▸), SHELXT2014/5 (Sheldrick, 2015a ▸), SHELXL2018/3 (Sheldrick, 2015b ▸) and OLEX2 (Dolomanov et al., 2009 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989022009264/dj2051sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989022009264/dj2051Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989022009264/dj2051Isup3.cml

CCDC reference: 2208338

Additional supporting information: crystallographic information; 3D view; checkCIF report

C13H16O3	Z = 2
Mr = 220.26	F(000) = 236
Triclinic, P1	Dx = 1.259 Mg m−3
a = 4.5931 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.9134 (9) Å	Cell parameters from 5145 reflections
c = 15.0764 (18) Å	θ = 2.5–26.6°
α = 74.808 (3)°	µ = 0.09 mm−1
β = 85.309 (4)°	T = 150 K
γ = 77.430 (3)°	PRISM, colourless
V = 581.18 (11) Å3	0.5 × 0.15 × 0.15 mm

Bruker kappa APEXII diffractometer	2647 independent reflections
Radiation source: X-ray tube, Siemens KFF Mo 2K-180	1865 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
Detector resolution: 8.3 pixels mm-1	θmax = 27.5°, θmin = 2.4°
φ and ω scans	h = −5→5
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	k = −11→11
Tmin = 0.668, Tmax = 0.746	l = −19→19
17290 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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.0417P)2 + 0.3763P] where P = (Fo2 + 2Fc2)/3
2647 reflections	(Δ/σ)max < 0.001
147 parameters	Δρmax = 0.33 e Å−3
0 restraints	Δρmin = −0.19 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

	x	y	z	Uiso*/Ueq
O3	0.5215 (3)	0.37762 (14)	0.60436 (8)	0.0300 (3)
O2	0.8022 (3)	0.53432 (15)	0.67363 (9)	0.0327 (3)
O1	0.7925 (3)	0.88375 (17)	0.59690 (12)	0.0498 (4)
C5	0.6121 (4)	0.3053 (2)	0.69197 (11)	0.0234 (4)
C6	0.5628 (4)	0.1597 (2)	0.74236 (12)	0.0262 (4)
H6	0.457467	0.102195	0.715929	0.031*
C4	0.7670 (4)	0.3919 (2)	0.73067 (12)	0.0247 (4)
C7	0.6660 (4)	0.0952 (2)	0.83221 (12)	0.0307 (4)
C9	0.8683 (4)	0.3293 (2)	0.81886 (13)	0.0322 (4)
H9	0.973015	0.386713	0.845569	0.039*
C3	0.9823 (4)	0.6233 (2)	0.70261 (14)	0.0319 (4)
H3A	1.174343	0.554383	0.725793	0.038*
H3B	0.878503	0.670214	0.752225	0.038*
C8	0.8175 (4)	0.1822 (2)	0.86875 (13)	0.0356 (5)
H8	0.888622	0.140217	0.929532	0.043*
C10	0.3618 (4)	0.2968 (2)	0.56109 (12)	0.0288 (4)
H10A	0.312228	0.360518	0.498608	0.043*
H10B	0.177676	0.280713	0.596581	0.043*
H10C	0.485826	0.193544	0.558386	0.043*
C11	0.6167 (5)	−0.0610 (2)	0.88692 (13)	0.0393 (5)
H11	0.697432	−0.096779	0.946634	0.047*
C2	1.0334 (4)	0.7498 (2)	0.62068 (15)	0.0376 (5)
H2	1.143379	0.712477	0.567846	0.045*
C12	0.4742 (5)	−0.1566 (2)	0.86288 (15)	0.0462 (6)
H12	0.392242	−0.122483	0.803335	0.055*
C1	1.0655 (5)	0.9043 (2)	0.62760 (18)	0.0450 (5)
H1A	1.065235	0.921634	0.689846	0.054*
H1B	1.195933	0.961206	0.581395	0.054*
C13	0.4301 (6)	−0.3142 (3)	0.92108 (17)	0.0583 (7)
H13A	0.509844	−0.396339	0.888173	0.087*
H13B	0.216596	−0.310609	0.934385	0.087*
H13C	0.534885	−0.338975	0.978846	0.087*

	U11	U22	U33	U12	U13	U23
O3	0.0366 (7)	0.0279 (7)	0.0274 (6)	−0.0150 (5)	−0.0068 (5)	−0.0015 (5)
O2	0.0337 (7)	0.0320 (7)	0.0361 (7)	−0.0159 (5)	−0.0066 (6)	−0.0057 (6)
O1	0.0354 (8)	0.0392 (9)	0.0766 (11)	−0.0119 (7)	−0.0132 (7)	−0.0106 (8)
C5	0.0197 (8)	0.0257 (9)	0.0231 (8)	−0.0015 (7)	0.0001 (6)	−0.0060 (7)
C6	0.0266 (9)	0.0240 (9)	0.0268 (9)	−0.0029 (7)	0.0019 (7)	−0.0068 (7)
C4	0.0185 (8)	0.0255 (9)	0.0290 (9)	−0.0020 (7)	0.0002 (7)	−0.0071 (7)
C7	0.0323 (10)	0.0251 (9)	0.0276 (9)	0.0058 (7)	0.0037 (7)	−0.0052 (7)
C9	0.0275 (9)	0.0362 (11)	0.0331 (10)	−0.0001 (8)	−0.0045 (8)	−0.0130 (8)
C3	0.0215 (9)	0.0350 (10)	0.0444 (11)	−0.0065 (7)	−0.0044 (8)	−0.0175 (9)
C8	0.0390 (11)	0.0352 (11)	0.0259 (9)	0.0063 (8)	−0.0046 (8)	−0.0064 (8)
C10	0.0315 (9)	0.0293 (10)	0.0288 (9)	−0.0132 (7)	−0.0015 (7)	−0.0070 (7)
C11	0.0492 (12)	0.0295 (11)	0.0281 (10)	0.0056 (9)	0.0039 (9)	−0.0005 (8)
C2	0.0257 (10)	0.0380 (11)	0.0545 (13)	−0.0114 (8)	0.0037 (9)	−0.0188 (10)
C12	0.0630 (15)	0.0281 (11)	0.0378 (12)	−0.0021 (10)	0.0079 (10)	−0.0001 (9)
C1	0.0323 (11)	0.0379 (12)	0.0731 (16)	−0.0144 (9)	−0.0054 (10)	−0.0211 (11)
C13	0.0827 (18)	0.0276 (12)	0.0526 (14)	−0.0028 (11)	0.0208 (13)	−0.0029 (10)

O3—C5	1.364 (2)	C3—C2	1.479 (3)
O3—C10	1.427 (2)	C8—H8	0.9500
O2—C4	1.368 (2)	C10—H10A	0.9800
O2—C3	1.425 (2)	C10—H10B	0.9800
O1—C2	1.430 (2)	C10—H10C	0.9800
O1—C1	1.435 (2)	C11—H11	0.9500
C5—C6	1.377 (2)	C11—C12	1.315 (3)
C5—C4	1.408 (2)	C2—H2	1.0000
C6—H6	0.9500	C2—C1	1.448 (3)
C6—C7	1.403 (2)	C12—H12	0.9500
C4—C9	1.377 (2)	C12—C13	1.495 (3)
C7—C8	1.382 (3)	C1—H1A	0.9900
C7—C11	1.474 (3)	C1—H1B	0.9900
C9—H9	0.9500	C13—H13A	0.9800
C9—C8	1.388 (3)	C13—H13B	0.9800
C3—H3A	0.9900	C13—H13C	0.9800
C3—H3B	0.9900
C5—O3—C10	117.72 (13)	O3—C10—H10C	109.5
C4—O2—C3	118.70 (14)	H10A—C10—H10B	109.5
C2—O1—C1	60.72 (12)	H10A—C10—H10C	109.5
O3—C5—C6	125.24 (15)	H10B—C10—H10C	109.5
O3—C5—C4	114.77 (15)	C7—C11—H11	116.1
C6—C5—C4	119.99 (16)	C12—C11—C7	127.7 (2)
C5—C6—H6	119.5	C12—C11—H11	116.1
C5—C6—C7	120.90 (17)	O1—C2—C3	116.11 (16)
C7—C6—H6	119.5	O1—C2—H2	115.7
O2—C4—C5	114.35 (15)	O1—C2—C1	59.82 (12)
O2—C4—C9	126.27 (16)	C3—C2—H2	115.7
C9—C4—C5	119.38 (16)	C1—C2—C3	122.05 (19)
C6—C7—C11	121.60 (18)	C1—C2—H2	115.7
C8—C7—C6	118.10 (17)	C11—C12—H12	117.2
C8—C7—C11	120.29 (17)	C11—C12—C13	125.7 (2)
C4—C9—H9	120.0	C13—C12—H12	117.2
C4—C9—C8	119.97 (18)	O1—C1—C2	59.46 (12)
C8—C9—H9	120.0	O1—C1—H1A	117.8
O2—C3—H3A	110.5	O1—C1—H1B	117.8
O2—C3—H3B	110.5	C2—C1—H1A	117.8
O2—C3—C2	106.23 (15)	C2—C1—H1B	117.8
H3A—C3—H3B	108.7	H1A—C1—H1B	115.0
C2—C3—H3A	110.5	C12—C13—H13A	109.5
C2—C3—H3B	110.5	C12—C13—H13B	109.5
C7—C8—C9	121.65 (17)	C12—C13—H13C	109.5
C7—C8—H8	119.2	H13A—C13—H13B	109.5
C9—C8—H8	119.2	H13A—C13—H13C	109.5
O3—C10—H10A	109.5	H13B—C13—H13C	109.5
O3—C10—H10B	109.5
O3—C5—C6—C7	179.86 (15)	C4—O2—C3—C2	167.73 (14)
O3—C5—C4—O2	−0.3 (2)	C4—C5—C6—C7	−0.3 (2)
O3—C5—C4—C9	−179.96 (15)	C4—C9—C8—C7	0.0 (3)
O2—C4—C9—C8	−179.64 (16)	C7—C11—C12—C13	−179.97 (19)
O2—C3—C2—O1	78.43 (19)	C3—O2—C4—C5	−173.56 (14)
O2—C3—C2—C1	147.72 (17)	C3—O2—C4—C9	6.1 (2)
C5—C6—C7—C8	0.2 (2)	C3—C2—C1—O1	−103.7 (2)
C5—C6—C7—C11	−179.63 (16)	C8—C7—C11—C12	178.9 (2)
C5—C4—C9—C8	0.0 (3)	C10—O3—C5—C6	0.2 (2)
C6—C5—C4—O2	179.83 (14)	C10—O3—C5—C4	−179.68 (14)
C6—C5—C4—C9	0.2 (2)	C11—C7—C8—C9	179.78 (17)
C6—C7—C8—C9	−0.1 (3)	C1—O1—C2—C3	113.5 (2)
C6—C7—C11—C12	−1.2 (3)