Crystal structure of taxodione isolated from Taxodium ascendens (B.)

Ke, R.-F.; Xu, S.-C.; Song, P.; Deng, S.-H.; Ma, X.-H.; Yang, X.-Z.

doi:10.1107/S205698901700946X

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ISSN: 2056-9890

Volume 73| Part 7| July 2017| Pages 1102-1104

https://doi.org/10.1107/S205698901700946X

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Crystal structure of taxodione isolated from Taxodium ascendens (B.)

Rui-Fang Ke,^a Shi-Cheng Xu,^a Ping Song,^b Shi-Hao Deng,^a Xin-Hua Ma ^a ^* and Xin-Zhou Yang ^a ^*

^aSchool of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, People's Republic of China, and ^bCollege of Chemistry and Life Science, Qinghai University for Nationalities, Xining 810007, People's Republic of China
^*Correspondence e-mail: maxinhua138@163.com, xzyang@mail.scuec.edu.cn

Edited by D.-J. Xu, Zhejiang University (Yuquan Campus), China (Received 17 June 2017; accepted 26 June 2017; online 30 June 2017)

The title compound [systematic name: (4bS)-4-hydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a-hexahydrophenanthrene-3,9-dione], C₂₀H₂₆O₃, is an abietane-type diterpene, which was isolated from Taxodium ascendens (B.). In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds, forming supramolecular chains propagating along the [001] direction.

Keywords: crystal structure; taxodione; Taxodium ascendens.

CCDC reference: 1551128

1. Chemical context

Taxodium ascendens Brongn belongs to the plant family Taxodiaceae and is native to the south-east of North America and can grow up to 25 m in height. It has yellow or orange–yellow seedballs, which mature in October. The plant is widely spread over southern China (e.g., Zhejiang, Henan, Jiangsu, Hubei and Yunnan Provinces) and because of its tolerance of water and drought, it has been used in the landscape at watersides. Previous chemical investigations of extracts isolated from the seeds of Taxodium ascendens (B.) revealed the presence of diterpenoids with an abietane framework, including as 6,7-dehydroroyleanone, salvinolone and xanthoperol (Kusumoto et al., 2009 ; González, 2015 ). Terpenoids, and in particular diterpenoids, are one of the most important classes of secondary metabolites found in the family Taxodiaceae, and have captured much attention in recent years due to their diverse bioactivities (Burmistrova et al., 2013 ; Iwamoto et al., 2001 ). In addition, the plant contains lignans and flavonoids (Si et al., 2001 ; Otto & Wilde, 2001 ) and antibacterial and inhibitory activity has been reported (Starks et al., 2014 ; Zhang et al., 2009 ). A detailed phytochemical investigation of a petroleum extract of the seeds of Taxodium ascendens Brongn has been carried out and a series of diterpenoids have been isolated, including the title compound taxodione, that show many biological properties including antibacterial (Yang et al., 2001 ), antioxidant (Kolak et al., 2009 ), antifungal (Topçu & Gören, 2007 ), and anticholinesterase activities (Topcu et al., 2013 ). Moreover, cytotoxic and tumor inhibitory properties of taxodione have been investigated by in vivo experiments (Abou Dahab et al., 2007 ). Herein we present the crystal structure of the title compound in order to establish unambiguously the stereochemical features of this natural product. The compound is soluble in chloroform but has poor solubility in methanol.

2. Structural commentary

The molecular structure of the title abietane diterpene is shown in Fig. 1. The structure contains one hydroxyl group located at atom C11, two ketone groups at C6 and C12 and three double bonds located between atoms C7 and C8, C9 and C11, and C13 and C14. An intramolecular O2—H2⋯O3 hydrogen bond (Fig. 1) stabilizes the molecular structure. The C14—C13—C12—C11 [−175.83 (19)°], C2—C13—C12—C17 [−168.47 (17)°], C3—C2—C1—C10 [178.98 (16)°] and C13—C2—C1—C6 [−169.12 (16)] torsion angles describe the geometry at the junctions of the three rings.

Figure 1
The molecular structure of the title compound, showing 50% probability displacement ellipsoids. A packing diagram of the title compound, with hydrogen bonds shown as dashed lines.

3. Supramolecular features

In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds, forming chains along [001] (Table 1 and Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O3	0.82	2.06	2.554 (2)	118
C11—H11⋯O3ⁱ	0.93	2.63	3.502 (2)	156
Symmetry code: (i) $[-x+{\script{1\over 2}}, -y+1, z-{\script{1\over 2}}]$ .

Figure 2
The packing of the title compound.

4. Database survey

A search of Cambridge Structural Database found no compounds with a similar structure to the title compound but a series of abietane-type diterpenoids has been reported such as horminone (Xiao et al., 2000 ) and 7α,12-dihydroxy-8,12-abietadiene-11,14-dione [or (4bS,8aS,10R)-3,10-dihydroxy-2-isopropyl-4b,8,8-trimethyl-1,4,4b,5,6,7,8,8a,9,10-decahydrophenanthrene-1,4-dione] (Razak et al., 2010 ).

5. Synthesis and crystallization

Taxodione was isolated from the seeds of Taxodium ascendens collected in Wuhan, China, in December 2015 (SC0725). The air-dried seeds of Taxodium ascendens (4.6 kg) were extracted with 95% EtOH and then treated with petroleum ether, ethyl acetate and n-butyl alcohol to give a PE extract (352 g), EtOAc extract (343 g) and n-BuOH extract (372 g). The EtOAc extract (343 g) was subjected to normal-phase silica gel column chromatography (300-400 mesh) with a gradient solvent system of CH₂Cl₂–MeOH (1:0–0:1, v/v, containing 0.1% formic acid) to give fifteen major fractions F1–F15. F5 (13 g) was subjected to sephadex LH-20 CC (CH₂Cl₂–MeOH, 3:1, containing 0.1% formic acid) to afford four fractions F5-1–F5-4. F5-2 was purified by semipreparative HPLC (CNCH₃/H₂O, 10:90→100:0, 40 min, containing 0.1% formic acid in both phases) to give a yellow solid, which was recrystallized from CH₂Cl₂:MeOH (7:1) affording yellow prismatic crystals suitable for X-ray diffraction analysis. For the ¹H and ¹³C NMR data of taxodione, see Masahiro et al. (2010 ).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Hydrogen atoms were positioned with idealized geometry and refined isotropically using a riding model with C—H = 0.97 Å (–CH₃, allowing for rotation), C—H = 0.98 Å (–CH₂), C—H = 0.99 Å, (–CH), C–H = 0.94 Å (–CH₂), and U_iso(H) = 1.5U_eq(CH₃) and U_iso(H) = 1.2U_eq(CH,CH₂), with the exception of the O—H hydrogen atom, which was refined freely, but with U_iso(H) = 1.5U_eq(O).

Table 2
Experimental details

Crystal data
Chemical formula	C₂₀H₂₆O₃
M_r	314.41
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	296
a, b, c (Å)	9.5008 (15), 13.220 (2), 13.584 (2)
V (Å³)	1706.1 (5)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.08
Crystal size (mm)	0.30 × 0.20 × 0.20

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	12903, 3355, 3111
R_int	0.046
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.088, 1.05
No. of reflections	3355
No. of parameters	215
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.20
Computer programs: APEX2 and SAINT (Bruker, 2007 ), SHELXS97 and SHELXTL (Sheldrick, 2008 ) and SHELXL2014 (Sheldrick, 2015 ).

Supporting information

CCDC reference: 1551128

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S205698901700946X/xu5903sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901700946X/xu5903Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S205698901700946X/xu5903Isup3.cdx

Supporting information file. DOI: https://doi.org/10.1107/S205698901700946X/xu5903Isup4.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

(4bS)-4-Hydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a-hexahydrophenanthrene-3,9-dione top

Crystal data top

C₂₀H₂₆O₃	D_x = 1.224 Mg m⁻³
M_r = 314.41	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 6770 reflections
a = 9.5008 (15) Å	θ = 2.6–30.9°
b = 13.220 (2) Å	µ = 0.08 mm⁻¹
c = 13.584 (2) Å	T = 296 K
V = 1706.1 (5) Å³	Prism, yellow
Z = 4	0.30 × 0.20 × 0.20 mm
F(000) = 680

Data collection top

Bruker APEXII CCD diffractometer	R_int = 0.046
φ and ω scans	θ_max = 26.0°, θ_min = 2.2°
12903 measured reflections	h = −11→11
3355 independent reflections	k = −16→16
3111 reflections with I > 2σ(I)	l = −16→16

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.034	w = 1/[σ²(F_o²) + (0.0417P)² + 0.2288P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.088	(Δ/σ)_max < 0.001
S = 1.05	Δρ_max = 0.17 e Å⁻³
3355 reflections	Δρ_min = −0.20 e Å⁻³
215 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.062 (5)

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O3	0.17963 (19)	0.52283 (12)	1.10546 (10)	0.0539 (4)
O1	0.2584 (2)	0.83099 (11)	0.64710 (11)	0.0647 (5)
C5	0.2103 (3)	1.03778 (15)	0.89721 (18)	0.0541 (6)
H5A	0.2972	1.0319	0.9343	0.065*
H5B	0.1947	1.1090	0.8841	0.065*
C4	0.0911 (3)	0.99858 (15)	0.95940 (19)	0.0583 (7)
H4A	0.0031	1.0060	0.9238	0.070*
H4B	0.0847	1.0380	1.0194	0.070*
C3	0.1139 (3)	0.88729 (15)	0.98514 (16)	0.0484 (5)
H3A	0.0359	0.8639	1.0252	0.058*
H3B	0.1992	0.8808	1.0238	0.058*
C2	0.12591 (19)	0.81999 (13)	0.89322 (13)	0.0326 (4)
C13	0.1741 (2)	0.71188 (13)	0.91885 (13)	0.0311 (4)
C12	0.2329 (2)	0.65054 (12)	0.83944 (13)	0.0322 (4)
C17	0.2566 (2)	0.54251 (13)	0.85234 (14)	0.0363 (4)
H17	0.2872	0.5051	0.7985	0.044*
C16	0.2365 (2)	0.49443 (13)	0.93772 (13)	0.0349 (4)
C18	0.2533 (2)	0.38153 (13)	0.95424 (15)	0.0409 (5)
H18	0.3060	0.3724	1.0156	0.049*
C19	0.3352 (3)	0.32924 (15)	0.87312 (19)	0.0558 (6)
H19A	0.4261	0.3603	0.8666	0.084*
H19B	0.2848	0.3353	0.8121	0.084*
H19C	0.3465	0.2590	0.8892	0.084*
C20	0.1092 (3)	0.33257 (16)	0.96823 (19)	0.0541 (6)
H20A	0.0561	0.3382	0.9084	0.081*
H20B	0.0599	0.3663	1.0205	0.081*
H20C	0.1210	0.2625	0.9847	0.081*
C14	0.1554 (2)	0.66396 (14)	1.00567 (14)	0.0358 (4)
O2	0.10090 (19)	0.70666 (12)	1.08780 (10)	0.0547 (4)
H2	0.0925	0.6635	1.1307	0.082*
C15	0.1912 (2)	0.55593 (14)	1.02095 (14)	0.0369 (4)
C6	0.2279 (2)	0.98258 (13)	0.79930 (15)	0.0403 (5)
C8	0.1081 (3)	1.01246 (17)	0.72952 (19)	0.0573 (6)
H8A	0.1165	0.9751	0.6692	0.086*
H8B	0.1135	1.0836	0.7158	0.086*
H8C	0.0193	0.9974	0.7599	0.086*
C9	0.3670 (3)	1.01768 (17)	0.7533 (2)	0.0574 (6)
H9A	0.4438	0.9988	0.7954	0.086*
H9B	0.3657	1.0899	0.7456	0.086*
H9C	0.3786	0.9864	0.6900	0.086*
C1	0.2375 (2)	0.86693 (12)	0.82138 (13)	0.0320 (4)
H1	0.3273	0.8591	0.8561	0.038*
C10	0.2524 (2)	0.80036 (13)	0.73123 (13)	0.0387 (4)
C11	0.2643 (2)	0.69172 (13)	0.75146 (13)	0.0389 (4)
H11	0.2949	0.6493	0.7012	0.047*
C7	−0.0201 (2)	0.80774 (16)	0.84503 (18)	0.0471 (5)
H7A	−0.0805	0.7701	0.8882	0.071*
H7B	−0.0104	0.7723	0.7837	0.071*
H7C	−0.0602	0.8733	0.8332	0.071*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O3	0.0756 (11)	0.0484 (8)	0.0378 (8)	−0.0038 (8)	0.0044 (8)	0.0116 (7)
O1	0.1165 (15)	0.0410 (7)	0.0366 (7)	0.0117 (10)	0.0151 (10)	0.0065 (6)
C5	0.0723 (16)	0.0303 (9)	0.0596 (13)	−0.0035 (10)	0.0031 (12)	−0.0107 (9)
C4	0.0842 (18)	0.0339 (11)	0.0567 (13)	0.0080 (11)	0.0172 (13)	−0.0137 (10)
C3	0.0671 (15)	0.0355 (10)	0.0427 (11)	0.0047 (10)	0.0112 (11)	−0.0102 (9)
C2	0.0355 (9)	0.0279 (8)	0.0345 (9)	0.0024 (7)	0.0033 (8)	−0.0043 (7)
C13	0.0319 (9)	0.0296 (8)	0.0319 (9)	0.0002 (7)	0.0010 (7)	−0.0032 (7)
C12	0.0353 (9)	0.0287 (8)	0.0325 (8)	0.0020 (7)	0.0003 (7)	−0.0013 (7)
C17	0.0443 (10)	0.0285 (8)	0.0361 (9)	0.0015 (8)	0.0006 (9)	−0.0037 (7)
C16	0.0360 (10)	0.0288 (8)	0.0398 (9)	−0.0019 (7)	−0.0065 (8)	0.0030 (7)
C18	0.0463 (12)	0.0293 (8)	0.0471 (10)	−0.0021 (9)	−0.0104 (10)	0.0079 (8)
C19	0.0617 (14)	0.0276 (9)	0.0780 (16)	0.0029 (9)	0.0017 (12)	−0.0003 (10)
C20	0.0544 (14)	0.0397 (11)	0.0681 (14)	−0.0118 (10)	−0.0038 (11)	0.0094 (11)
C14	0.0364 (10)	0.0369 (9)	0.0341 (9)	−0.0001 (8)	0.0029 (7)	−0.0025 (7)
O2	0.0766 (12)	0.0513 (9)	0.0364 (8)	0.0070 (8)	0.0202 (8)	0.0013 (7)
C15	0.0382 (10)	0.0385 (9)	0.0340 (10)	−0.0063 (8)	−0.0013 (8)	0.0053 (8)
C6	0.0446 (11)	0.0264 (8)	0.0499 (11)	0.0006 (8)	0.0003 (9)	0.0003 (8)
C8	0.0666 (15)	0.0361 (10)	0.0693 (15)	0.0112 (10)	−0.0097 (12)	0.0083 (10)
C9	0.0596 (15)	0.0385 (11)	0.0740 (15)	−0.0057 (10)	0.0103 (13)	0.0092 (11)
C1	0.0332 (9)	0.0260 (8)	0.0367 (9)	0.0030 (7)	−0.0013 (8)	−0.0014 (7)
C10	0.0497 (11)	0.0314 (8)	0.0349 (9)	0.0050 (9)	0.0069 (9)	0.0023 (7)
C11	0.0549 (12)	0.0294 (8)	0.0325 (8)	0.0058 (8)	0.0059 (9)	−0.0046 (7)
C7	0.0344 (10)	0.0387 (10)	0.0683 (14)	0.0030 (8)	−0.0027 (10)	0.0005 (10)

Geometric parameters (Å, º) top

O3—C15	1.233 (2)	C19—H19A	0.9600
O1—C10	1.214 (2)	C19—H19B	0.9600
C5—C4	1.506 (4)	C19—H19C	0.9600
C5—C6	1.526 (3)	C20—H20A	0.9600
C5—H5A	0.9700	C20—H20B	0.9600
C5—H5B	0.9700	C20—H20C	0.9600
C4—C3	1.528 (3)	C14—O2	1.353 (2)
C4—H4A	0.9700	C14—C15	1.483 (3)
C4—H4B	0.9700	O2—H2	0.8200
C3—C2	1.538 (2)	C6—C8	1.533 (3)
C3—H3A	0.9700	C6—C9	1.534 (3)
C3—H3B	0.9700	C6—C1	1.561 (2)
C2—C13	1.541 (2)	C8—H8A	0.9600
C2—C7	1.542 (3)	C8—H8B	0.9600
C2—C1	1.569 (3)	C8—H8C	0.9600
C13—C14	1.350 (3)	C9—H9A	0.9600
C13—C12	1.461 (2)	C9—H9B	0.9600
C12—C11	1.347 (2)	C9—H9C	0.9600
C12—C17	1.456 (2)	C1—C10	1.515 (2)
C17—C16	1.336 (3)	C1—H1	0.9800
C17—H17	0.9300	C10—C11	1.467 (2)
C16—C15	1.458 (3)	C11—H11	0.9300
C16—C18	1.518 (2)	C7—H7A	0.9600
C18—C19	1.515 (3)	C7—H7B	0.9600
C18—C20	1.527 (3)	C7—H7C	0.9600
C18—H18	0.9800

C4—C5—C6	114.00 (18)	C18—C20—H20B	109.5
C4—C5—H5A	108.8	H20A—C20—H20B	109.5
C6—C5—H5A	108.8	C18—C20—H20C	109.5
C4—C5—H5B	108.8	H20A—C20—H20C	109.5
C6—C5—H5B	108.8	H20B—C20—H20C	109.5
H5A—C5—H5B	107.6	C13—C14—O2	125.06 (17)
C5—C4—C3	110.7 (2)	C13—C14—C15	122.97 (17)
C5—C4—H4A	109.5	O2—C14—C15	111.96 (16)
C3—C4—H4A	109.5	C14—O2—H2	109.5
C5—C4—H4B	109.5	O3—C15—C16	123.39 (18)
C3—C4—H4B	109.5	O3—C15—C14	116.86 (18)
H4A—C4—H4B	108.1	C16—C15—C14	119.75 (16)
C4—C3—C2	112.45 (18)	C5—C6—C8	109.54 (18)
C4—C3—H3A	109.1	C5—C6—C9	107.74 (18)
C2—C3—H3A	109.1	C8—C6—C9	108.04 (18)
C4—C3—H3B	109.1	C5—C6—C1	107.90 (16)
C2—C3—H3B	109.1	C8—C6—C1	114.51 (16)
H3A—C3—H3B	107.8	C9—C6—C1	108.91 (16)
C3—C2—C13	112.04 (15)	C6—C8—H8A	109.5
C3—C2—C7	109.80 (17)	C6—C8—H8B	109.5
C13—C2—C7	105.41 (15)	H8A—C8—H8B	109.5
C3—C2—C1	109.04 (15)	C6—C8—H8C	109.5
C13—C2—C1	107.86 (14)	H8A—C8—H8C	109.5
C7—C2—C1	112.67 (15)	H8B—C8—H8C	109.5
C14—C13—C12	115.76 (15)	C6—C9—H9A	109.5
C14—C13—C2	126.42 (16)	C6—C9—H9B	109.5
C12—C13—C2	117.50 (15)	H9A—C9—H9B	109.5
C11—C12—C17	117.98 (16)	C6—C9—H9C	109.5
C11—C12—C13	121.04 (15)	H9A—C9—H9C	109.5
C17—C12—C13	120.97 (15)	H9B—C9—H9C	109.5
C16—C17—C12	123.29 (17)	C10—C1—C6	114.79 (15)
C16—C17—H17	118.4	C10—C1—C2	109.64 (14)
C12—C17—H17	118.4	C6—C1—C2	117.86 (15)
C17—C16—C15	116.75 (16)	C10—C1—H1	104.3
C17—C16—C18	125.52 (17)	C6—C1—H1	104.3
C15—C16—C18	117.70 (16)	C2—C1—H1	104.3
C19—C18—C16	113.28 (17)	O1—C10—C11	119.97 (17)
C19—C18—C20	110.95 (18)	O1—C10—C1	124.87 (17)
C16—C18—C20	109.92 (17)	C11—C10—C1	115.13 (15)
C19—C18—H18	107.5	C12—C11—C10	123.03 (16)
C16—C18—H18	107.5	C12—C11—H11	118.5
C20—C18—H18	107.5	C10—C11—H11	118.5
C18—C19—H19A	109.5	C2—C7—H7A	109.5
C18—C19—H19B	109.5	C2—C7—H7B	109.5
H19A—C19—H19B	109.5	H7A—C7—H7B	109.5
C18—C19—H19C	109.5	C2—C7—H7C	109.5
H19A—C19—H19C	109.5	H7A—C7—H7C	109.5
H19B—C19—H19C	109.5	H7B—C7—H7C	109.5
C18—C20—H20A	109.5

C6—C5—C4—C3	60.6 (3)	C17—C16—C15—C14	6.4 (3)
C5—C4—C3—C2	−58.9 (3)	C18—C16—C15—C14	−172.15 (17)
C4—C3—C2—C13	170.16 (19)	C13—C14—C15—O3	174.55 (19)
C4—C3—C2—C7	−73.1 (2)	O2—C14—C15—O3	−6.4 (3)
C4—C3—C2—C1	50.8 (2)	C13—C14—C15—C16	−5.8 (3)
C3—C2—C13—C14	26.0 (3)	O2—C14—C15—C16	173.20 (18)
C7—C2—C13—C14	−93.4 (2)	C4—C5—C6—C8	72.5 (2)
C1—C2—C13—C14	146.02 (18)	C4—C5—C6—C9	−170.2 (2)
C3—C2—C13—C12	−160.72 (17)	C4—C5—C6—C1	−52.8 (3)
C7—C2—C13—C12	79.9 (2)	C5—C6—C1—C10	178.84 (18)
C1—C2—C13—C12	−40.7 (2)	C8—C6—C1—C10	56.6 (2)
C14—C13—C12—C11	−175.83 (19)	C9—C6—C1—C10	−64.5 (2)
C2—C13—C12—C11	10.2 (3)	C5—C6—C1—C2	47.3 (2)
C14—C13—C12—C17	5.5 (3)	C8—C6—C1—C2	−74.9 (2)
C2—C13—C12—C17	−168.47 (17)	C9—C6—C1—C2	164.01 (18)
C11—C12—C17—C16	176.3 (2)	C3—C2—C1—C10	178.98 (16)
C13—C12—C17—C16	−5.0 (3)	C13—C2—C1—C10	57.08 (18)
C12—C17—C16—C15	−1.2 (3)	C7—C2—C1—C10	−58.84 (19)
C12—C17—C16—C18	177.20 (19)	C3—C2—C1—C6	−47.2 (2)
C17—C16—C18—C19	16.5 (3)	C13—C2—C1—C6	−169.12 (16)
C15—C16—C18—C19	−165.18 (19)	C7—C2—C1—C6	75.0 (2)
C17—C16—C18—C20	−108.3 (2)	C6—C1—C10—O1	0.8 (3)
C15—C16—C18—C20	70.1 (2)	C2—C1—C10—O1	136.1 (2)
C12—C13—C14—O2	−179.14 (19)	C6—C1—C10—C11	178.87 (18)
C2—C13—C14—O2	−5.7 (3)	C2—C1—C10—C11	−45.8 (2)
C12—C13—C14—C15	−0.3 (3)	C17—C12—C11—C10	−176.54 (19)
C2—C13—C14—C15	173.14 (18)	C13—C12—C11—C10	4.8 (3)
C17—C16—C15—O3	−174.0 (2)	O1—C10—C11—C12	−167.3 (2)
C18—C16—C15—O3	7.5 (3)	C1—C10—C11—C12	14.5 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3	0.82	2.06	2.554 (2)	118
C11—H11···O3ⁱ	0.93	2.63	3.502 (2)	156

Symmetry code: (i) −x+1/2, −y+1, z−1/2.

Funding information

Funding for this research was provided by: Natural Science Foundation of Qinghai Province (grant No. 2016-ZJ-908); National Natural Science Foundation of China grant (grant No. 81573561).

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