Absolute configuration of fibaruretin B

Fun, H.-K.; Salae, A.W.; Razak, I.A.; Khairuddean, M.; Chantrapromma, S.

doi:10.1107/S1600536811014887

organic compounds

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ISSN: 2056-9890

Volume 67| Part 5| May 2011| Pages o1246-o1247

doi:10.1107/S1600536811014887

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Absolute configuration of fibaruretin B

Hoong-Kun Fun,^a ^*‡ Abdul Wahab Salae,^a § Ibrahim Abdul Razak,^a Melati Khairuddean ^b and Suchada Chantrapromma ^c ¶

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bSchool of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^cCrystal Materials Research Unit, Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand
^*Correspondence e-mail: hkfun@usm.my

(Received 15 April 2011; accepted 20 April 2011; online 29 April 2011)

The title furanoditerpenoid, known as fibaruretin B (systematic name: 2β,3α-dihydroxy-2,3,7,8α-tetrahydropenianthic acid lactone), C₂₀H₂₄O₇, was isolated from the roots of Arcangelisia flava. The absolute configurations at positions 2, 3, 4, 4a, 7, 9, 10a and 10b of fibaruretin B are S, R, S, R, S, S, S and S, respectively. In the crystal structure, the molecules are linked into infinite chains along the c axis by O—H⋯O hydrogen bonds and weak C—H⋯O interactions.

Related literature

For ring conformations, see: Cremer & Pople (1975 ). For bond-length data, see: Allen et al. (1987 ). For background to and activities of furanoditerpenoids, see: Ito & Furukawa (1969 ); Keawpradub et al. (2005 ); Moody et al. (2006 ); Nguyen-Pouplin et al. (2007 ); Su et al. (2008 ). For a related structure, see: Bakhari et al. (1998 ). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ).

Experimental

Crystal data

C₂₀H₂₄O₇
M_r = 376.39
Monoclinic, P 2₁
a = 7.0942 (2) Å
b = 11.7149 (4) Å
c = 10.1921 (3) Å
β = 90.805 (1)°
V = 846.96 (5) Å³
Z = 2
Cu Kα radiation
μ = 0.93 mm⁻¹
T = 100 K
0.43 × 0.12 × 0.08 mm

Data collection

Bruker APEX DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.692, T_max = 0.926
11247 measured reflections
2645 independent reflections
2641 reflections with I > 2σ(I)
R_int = 0.018

Refinement

R[F² > 2σ(F²)] = 0.025
wR(F²) = 0.066
S = 1.09
2645 reflections
254 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.15 e Å⁻³
Absolute structure: Flack (1983 ), with 1098 Friedel pairs
Flack parameter: 0.03 (12)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H1O3⋯O5ⁱ	0.86 (3)	2.54 (3)	3.1305 (15)	127 (2)
O4—H1O4⋯O6ⁱ	0.87 (3)	2.12 (3)	2.9708 (14)	165 (2)
C3—H3A⋯O5ⁱ	0.98	2.39	3.1295 (16)	131
C6—H6A⋯O2	0.97	2.43	3.1718 (19)	133
C8—H8A⋯O2ⁱⁱ	0.98	2.29	3.2113 (19)	157
C19—H19C⋯O3	0.96	2.31	2.9489 (18)	124
C20—H20B⋯O7ⁱⁱⁱ	0.96	2.53	3.4613 (18)	164
Symmetry codes: (i) x, y, z+1; (ii) $[-x+1, y-{\script{1\over 2}}, -z+1]$ ; (iii) $[-x, y+{\script{1\over 2}}, -z]$ .

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811014887/is2703sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811014887/is2703Isup2.hkl

checkCIF report

Comment top

Furanoditerpenoids are secondary metabolites which were found in Menispermaceae plants such as Fibraurea chloroleuta Miers (Ito & Furukawa, 1969), Fibraurea tinctoria Lour. (Su et al., 2008) and Sphenocentrum jollyanum Pierre (Moody et al., 2006). They were found to possess biological properties such as anti-inflammatory and antimalarial activities. Arcangelisia flava (Menispermaceae), commonly called `Khaminkhruea' in the southern Thailand, is widely distributed from Hainan (China), Indo-China, southern peninsular Thailand, peninsular Malaysia, Sumatra, Java, Borneo, the Philipines, Sulawesi, the Northern Moluccas to New Guinea. It is an available medicinal plant used for the treatment of malaria, dysentery and as a tonic. The antimalarial, cytotoxic and antioxidant effects of this plant have been reported (Nguyen-Pouplin et al., 2007; Keawpradub et al., 2005). During the course of our study of bioactive compounds from medicinal plants, the title furanoditerpenoid compound, (I), which is known as fibaruretin B, was isolated for the first time from the roots of Arcangelisia flava (Menispermaceae) which were collected from Songkhla province in the southern part of Thailand. The absolute configuration of (I) was determined by making use of the anomalous scattering of Cu Kα radiation with the Flack parameter being refined to 0.03 (12).

The molecule of (I) has four fused rings consisting of one five- and three six-membered rings (A/B/C/D) (Fig. 1). The two cyclohexane rings A and B are cis fused, whereas the cyclohexane ring B and pyran ring C are trans fused. The cyclohexane ring A (C1–C5/C10) is in an envelope conformation, with the pucker atom C3 (0.4436 (16) Å) and puckering parameter Q = 0.6349 (16) Å, θ = 46.82 (14)° and ϕ = 115.0 (2)° (Cremer & Pople, 1975). The cyclohexane ring B (C5–C10) adopts a twisted boat conformation with puckering parameter Q = 0.7098 (15) Å, θ = 99.25 (12)° and ϕ = 45.65 (13)°. The pyran ring C (O5/C17/C8/C9/C11/C12) is in a boat conformation with puckering parameter Q = 0.7026 (15) Å, θ = 89.67 (12)° and ϕ = 241.68 (12)°. The tetrahydrofuran ring D (O1/C2–C4/C18) is in an envelope conformation, with the pucker atom C3 [-0.2883 (16) Å] and puckering parameter Q = 0.4584 (16) Å and ϕ = 258.04 (19)°. The furan ring (C13–C16/O7) is planar with an r.m.s. 0.0028 (2) Å and is equatorially attached to the pyran ring C with torsion angles O5—C12—C13—C14 = -76.91 (15)° and O5—C12—C13—C16 = 105.01 (16)°. The bond distances in (I) are within normal ranges (Allen et al., 1987) and comparable with the related structure (Bakhari et al., 1998).

The absolute configuration at atoms C2, C3, C4, C5, C8, C12, C9, C10 or positions 2, 3, 4, 4a, 7, 9, 10a and 10b of the fibaruretin B are S, R, S, R, S, S, S and S, respectively which agree with the previous stereochemistry of fibaruretin B (Su et al., 2008).

In the crystal packing of (I) (Fig. 2), the molecules are linked into chains along the c axis through O—H···O hydrogen bonds and C—H···O weak interactions (Fig. 2 and Table 1) and the crystal is stabilized by these interactions.

Related literature top

For ring conformations, see: Cremer & Pople (1975). For bond-length data, see: Allen et al. (1987). For background to and activities of furanoditerpenoid, see: Ito & Furukawa (1969); Keawpradub et al. (2005); Moody et al. (2006); Nguyen-Pouplin et al. (2007); Su et al. (2008). For a related structure, see: Bakhari et al. (1998). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Experimental top

The air-dried roots of Arcangelisia flava (Menispermaceae) (1.8 kg) were extracted with CH₂Cl₂ (2 × 10 l) under room temperature. The combined extracts were concentrated under reduced pressure to give a yellow extract (30.1 g) which was subjected to quick column chromatography over silica gel using solvents of increasing polarity from n-hexane to EtOAc to afford 10 fractions (F1–F10). Fraction F9 was further purified by column chromatography using CH₂Cl₂–EtOAc (6:4), yielding the title compound as a white solid (275.3 mg). Colorless needle-shaped single crystals of the title compound suitable for X-ray structure determination were recrystallized from CH₂Cl₂ by the slow evaporation of the solvent at room temperature after several days (m.p. 539–540 K).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The crystal packing of (I) viewed along the a axis, showing chains along the c axis. Hydrogen bonds are drawn as dashed lines.

2β,3α-dihydroxy-2,3,7,8α-tetrahydropenianthic acid lactone top

Crystal data top

C₂₀H₂₄O₇	F(000) = 400
M_r = 376.39	D_x = 1.476 Mg m⁻³
Monoclinic, P2₁	Melting point = 539–540 K
Hall symbol: P 2yb	Cu Kα radiation, λ = 1.54178 Å
a = 7.0942 (2) Å	Cell parameters from 2645 reflections
b = 11.7149 (4) Å	θ = 4.3–66.5°
c = 10.1921 (3) Å	µ = 0.93 mm⁻¹
β = 90.805 (1)°	T = 100 K
V = 846.96 (5) Å³	Needle, colourless
Z = 2	0.43 × 0.12 × 0.08 mm

Data collection top

Bruker APEX DUO CCD area-detector diffractometer	2645 independent reflections
Radiation source: sealed tube	2641 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.018
ϕ and ω scans	θ_max = 66.5°, θ_min = 4.3°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −8→8
T_min = 0.692, T_max = 0.926	k = −11→13
11247 measured reflections	l = −11→12

Refinement top

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)] = 0.025	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.066	w = 1/[σ²(F_o²) + (0.0393P)² + 0.1838P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max = 0.001
2645 reflections	Δρ_max = 0.19 e Å⁻³
254 parameters	Δρ_min = −0.15 e Å⁻³
1 restraint	Absolute structure: Flack (1983), with 1098 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.03 (12)

Crystal data top

C₂₀H₂₄O₇	V = 846.96 (5) Å³
M_r = 376.39	Z = 2
Monoclinic, P2₁	Cu Kα radiation
a = 7.0942 (2) Å	µ = 0.93 mm⁻¹
b = 11.7149 (4) Å	T = 100 K
c = 10.1921 (3) Å	0.43 × 0.12 × 0.08 mm
β = 90.805 (1)°

Data collection top

Bruker APEX DUO CCD area-detector diffractometer	2645 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	2641 reflections with I > 2σ(I)
T_min = 0.692, T_max = 0.926	R_int = 0.018
11247 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.025	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.066	Δρ_max = 0.19 e Å⁻³
S = 1.09	Δρ_min = −0.15 e Å⁻³
2645 reflections	Absolute structure: Flack (1983), with 1098 Friedel pairs
254 parameters	Absolute structure parameter: 0.03 (12)
1 restraint

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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.

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 > 2sigma(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.

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

	x	y	z	U_iso*/U_eq
O1	0.09153 (14)	1.02466 (10)	0.68755 (10)	0.0211 (2)
O2	0.32424 (17)	1.15137 (10)	0.70124 (12)	0.0296 (3)
O3	0.27902 (16)	0.75672 (11)	0.80552 (11)	0.0252 (3)
H1O3	0.255 (4)	0.732 (2)	0.883 (3)	0.061 (8)*
O4	0.55436 (14)	0.96856 (12)	0.80516 (10)	0.0239 (3)
H1O4	0.527 (3)	0.965 (2)	0.888 (3)	0.046 (6)*
O5	0.31561 (13)	0.83615 (10)	0.09804 (9)	0.0178 (2)
O6	0.53283 (13)	0.96975 (11)	0.09604 (9)	0.0206 (2)
O7	−0.09239 (17)	0.58024 (10)	−0.04095 (11)	0.0275 (3)
C1	0.08225 (19)	0.83863 (15)	0.58193 (13)	0.0188 (3)
H1A	−0.0153	0.8680	0.5235	0.023*
H1B	0.0542	0.7589	0.5981	0.023*
C2	0.07216 (19)	0.90202 (14)	0.70997 (14)	0.0185 (3)
H2A	−0.0459	0.8851	0.7547	0.022*
C3	0.2412 (2)	0.87467 (14)	0.79792 (13)	0.0181 (3)
H3A	0.2207	0.9052	0.8861	0.022*
C4	0.39121 (19)	0.94530 (14)	0.72888 (14)	0.0170 (3)
C5	0.45100 (19)	0.89413 (13)	0.59309 (13)	0.0147 (3)
C6	0.56241 (19)	0.98757 (13)	0.51939 (14)	0.0162 (3)
H6A	0.4927	1.0586	0.5247	0.019*
H6B	0.6821	0.9989	0.5647	0.019*
C7	0.60174 (18)	0.96286 (14)	0.37404 (14)	0.0163 (3)
H7A	0.6105	1.0347	0.3272	0.020*
H7B	0.7225	0.9246	0.3676	0.020*
C8	0.44977 (18)	0.88869 (13)	0.30780 (13)	0.0145 (3)
H8A	0.4901	0.8096	0.3218	0.017*
C9	0.25169 (18)	0.89794 (14)	0.37078 (13)	0.0151 (3)
C10	0.27476 (18)	0.84594 (14)	0.51044 (13)	0.0147 (3)
H10A	0.3078	0.7660	0.4940	0.018*
C11	0.1130 (2)	0.82256 (15)	0.28832 (13)	0.0200 (3)
H11A	0.0532	0.7684	0.3465	0.024*
H11B	0.0149	0.8712	0.2516	0.024*
C12	0.20406 (19)	0.75715 (14)	0.17735 (13)	0.0158 (3)
H12A	0.2855	0.6969	0.2132	0.019*
C13	0.0605 (2)	0.70654 (14)	0.08547 (14)	0.0169 (3)
C14	−0.1096 (2)	0.75809 (15)	0.03551 (14)	0.0214 (3)
H14A	−0.1519	0.8318	0.0517	0.026*
C15	−0.1952 (2)	0.67891 (16)	−0.03912 (14)	0.0245 (4)
H15A	−0.3091	0.6896	−0.0837	0.029*
C16	0.0642 (2)	0.60018 (15)	0.03548 (15)	0.0226 (3)
H16A	0.1600	0.5475	0.0508	0.027*
C17	0.43951 (19)	0.90427 (14)	0.16102 (14)	0.0161 (3)
C18	0.2742 (2)	1.05332 (15)	0.70502 (14)	0.0196 (3)
C19	0.5852 (2)	0.79280 (14)	0.61724 (14)	0.0185 (3)
H19A	0.6860	0.8160	0.6751	0.028*
H19B	0.6363	0.7681	0.5353	0.028*
H19C	0.5170	0.7311	0.6564	0.028*
C20	0.17620 (19)	1.02044 (14)	0.36919 (14)	0.0185 (3)
H20A	0.0509	1.0215	0.4036	0.028*
H20B	0.1736	1.0485	0.2807	0.028*
H20C	0.2567	1.0681	0.4223	0.028*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0209 (5)	0.0249 (7)	0.0177 (5)	0.0024 (4)	0.0029 (4)	−0.0014 (5)
O2	0.0385 (6)	0.0192 (7)	0.0313 (6)	−0.0040 (5)	0.0147 (5)	−0.0054 (5)
O3	0.0353 (6)	0.0215 (6)	0.0189 (6)	−0.0015 (5)	0.0068 (5)	0.0065 (5)
O4	0.0183 (5)	0.0407 (7)	0.0125 (5)	−0.0077 (5)	−0.0016 (4)	−0.0034 (5)
O5	0.0203 (5)	0.0222 (6)	0.0109 (4)	−0.0035 (4)	0.0008 (4)	−0.0001 (4)
O6	0.0215 (5)	0.0262 (6)	0.0143 (5)	−0.0042 (5)	0.0021 (4)	0.0028 (4)
O7	0.0346 (6)	0.0253 (7)	0.0225 (6)	−0.0079 (5)	−0.0056 (4)	−0.0038 (5)
C1	0.0175 (7)	0.0248 (9)	0.0141 (6)	−0.0075 (6)	0.0010 (5)	−0.0010 (6)
C2	0.0169 (7)	0.0244 (9)	0.0145 (7)	−0.0046 (6)	0.0041 (5)	0.0001 (6)
C3	0.0209 (7)	0.0223 (9)	0.0112 (7)	−0.0035 (6)	0.0025 (5)	−0.0010 (6)
C4	0.0162 (6)	0.0217 (9)	0.0131 (6)	−0.0044 (6)	−0.0011 (5)	−0.0020 (6)
C5	0.0147 (6)	0.0171 (8)	0.0124 (6)	−0.0016 (6)	0.0005 (5)	−0.0007 (6)
C6	0.0148 (6)	0.0187 (8)	0.0152 (7)	−0.0021 (6)	−0.0003 (5)	−0.0005 (6)
C7	0.0140 (6)	0.0205 (8)	0.0144 (7)	−0.0022 (6)	0.0016 (5)	0.0005 (6)
C8	0.0143 (6)	0.0155 (8)	0.0138 (7)	0.0006 (5)	0.0007 (5)	0.0001 (6)
C9	0.0142 (6)	0.0189 (8)	0.0122 (6)	−0.0022 (6)	0.0012 (5)	−0.0010 (6)
C10	0.0153 (6)	0.0158 (8)	0.0130 (7)	−0.0029 (5)	0.0010 (5)	−0.0015 (5)
C11	0.0159 (6)	0.0296 (9)	0.0144 (7)	−0.0044 (6)	0.0011 (5)	−0.0045 (6)
C12	0.0170 (6)	0.0171 (8)	0.0132 (6)	−0.0010 (6)	0.0001 (5)	0.0029 (6)
C13	0.0197 (7)	0.0185 (8)	0.0124 (6)	−0.0032 (6)	0.0022 (5)	0.0012 (6)
C14	0.0226 (7)	0.0249 (9)	0.0167 (7)	−0.0005 (6)	−0.0008 (5)	0.0000 (6)
C15	0.0248 (7)	0.0310 (10)	0.0177 (7)	−0.0055 (7)	−0.0041 (6)	0.0004 (6)
C16	0.0280 (8)	0.0209 (9)	0.0190 (7)	−0.0036 (6)	−0.0008 (6)	−0.0012 (6)
C17	0.0146 (6)	0.0178 (8)	0.0158 (7)	0.0040 (6)	0.0010 (5)	−0.0013 (6)
C18	0.0254 (7)	0.0210 (9)	0.0125 (6)	−0.0025 (6)	0.0070 (5)	−0.0040 (6)
C19	0.0166 (6)	0.0218 (9)	0.0172 (6)	0.0012 (6)	0.0005 (5)	0.0035 (6)
C20	0.0171 (6)	0.0232 (9)	0.0152 (7)	0.0032 (6)	−0.0005 (5)	0.0016 (6)

Geometric parameters (Å, º) top

O1—C18	1.3482 (19)	C7—C8	1.5338 (19)
O1—C2	1.462 (2)	C7—H7A	0.9700
O2—C18	1.203 (2)	C7—H7B	0.9700
O3—C3	1.409 (2)	C8—C17	1.5078 (19)
O3—H1O3	0.86 (3)	C8—C9	1.5568 (17)
O4—C4	1.4117 (16)	C8—H8A	0.9800
O4—H1O4	0.87 (3)	C9—C20	1.532 (2)
O5—C17	1.3437 (18)	C9—C10	1.5548 (19)
O5—C12	1.4677 (17)	C9—C11	1.5593 (19)
O6—C17	1.2156 (19)	C10—H10A	0.9800
O7—C15	1.367 (2)	C11—C12	1.518 (2)
O7—C16	1.3677 (18)	C11—H11A	0.9700
C1—C2	1.504 (2)	C11—H11B	0.9700
C1—C10	1.5593 (18)	C12—C13	1.4962 (19)
C1—H1A	0.9700	C12—H12A	0.9800
C1—H1B	0.9700	C13—C16	1.347 (2)
C2—C3	1.521 (2)	C13—C14	1.436 (2)
C2—H2A	0.9800	C14—C15	1.340 (2)
C3—C4	1.528 (2)	C14—H14A	0.9300
C3—H3A	0.9800	C15—H15A	0.9300
C4—C18	1.531 (2)	C16—H16A	0.9300
C4—C5	1.5720 (18)	C19—H19A	0.9600
C5—C19	1.539 (2)	C19—H19B	0.9600
C5—C6	1.550 (2)	C19—H19C	0.9600
C5—C10	1.6006 (18)	C20—H20A	0.9600
C6—C7	1.5388 (19)	C20—H20B	0.9600
C6—H6A	0.9700	C20—H20C	0.9600
C6—H6B	0.9700

C18—O1—C2	108.45 (12)	C20—C9—C8	112.23 (12)
C3—O3—H1O3	109.8 (19)	C10—C9—C8	105.44 (11)
C4—O4—H1O4	109.2 (15)	C20—C9—C11	107.87 (11)
C17—O5—C12	117.74 (10)	C10—C9—C11	109.21 (12)
C15—O7—C16	106.07 (12)	C8—C9—C11	107.75 (11)
C2—C1—C10	115.53 (12)	C9—C10—C1	111.57 (11)
C2—C1—H1A	108.4	C9—C10—C5	114.52 (11)
C10—C1—H1A	108.4	C1—C10—C5	117.14 (11)
C2—C1—H1B	108.4	C9—C10—H10A	103.9
C10—C1—H1B	108.4	C1—C10—H10A	103.9
H1A—C1—H1B	107.5	C5—C10—H10A	103.9
O1—C2—C1	110.12 (12)	C12—C11—C9	114.55 (11)
O1—C2—C3	102.95 (12)	C12—C11—H11A	108.6
C1—C2—C3	111.13 (12)	C9—C11—H11A	108.6
O1—C2—H2A	110.8	C12—C11—H11B	108.6
C1—C2—H2A	110.8	C9—C11—H11B	108.6
C3—C2—H2A	110.8	H11A—C11—H11B	107.6
O3—C3—C2	112.76 (13)	O5—C12—C13	105.82 (10)
O3—C3—C4	115.02 (13)	O5—C12—C11	109.30 (12)
C2—C3—C4	99.38 (11)	C13—C12—C11	111.92 (11)
O3—C3—H3A	109.7	O5—C12—H12A	109.9
C2—C3—H3A	109.7	C13—C12—H12A	109.9
C4—C3—H3A	109.7	C11—C12—H12A	109.9
O4—C4—C3	114.97 (12)	C16—C13—C14	105.98 (13)
O4—C4—C18	111.49 (13)	C16—C13—C12	125.95 (15)
C3—C4—C18	98.12 (11)	C14—C13—C12	128.05 (15)
O4—C4—C5	109.22 (11)	C15—C14—C13	106.37 (16)
C3—C4—C5	113.41 (12)	C15—C14—H14A	126.8
C18—C4—C5	109.13 (12)	C13—C14—H14A	126.8
C19—C5—C6	107.67 (11)	C14—C15—O7	110.84 (14)
C19—C5—C4	109.10 (11)	C14—C15—H15A	124.6
C6—C5—C4	107.64 (12)	O7—C15—H15A	124.6
C19—C5—C10	106.79 (12)	C13—C16—O7	110.72 (14)
C6—C5—C10	113.19 (11)	C13—C16—H16A	124.6
C4—C5—C10	112.30 (10)	O7—C16—H16A	124.6
C7—C6—C5	115.73 (12)	O6—C17—O5	118.17 (13)
C7—C6—H6A	108.3	O6—C17—C8	126.71 (13)
C5—C6—H6A	108.3	O5—C17—C8	115.10 (12)
C7—C6—H6B	108.3	O2—C18—O1	121.13 (15)
C5—C6—H6B	108.3	O2—C18—C4	129.41 (14)
H6A—C6—H6B	107.4	O1—C18—C4	109.46 (13)
C8—C7—C6	113.24 (11)	C5—C19—H19A	109.5
C8—C7—H7A	108.9	C5—C19—H19B	109.5
C6—C7—H7A	108.9	H19A—C19—H19B	109.5
C8—C7—H7B	108.9	C5—C19—H19C	109.5
C6—C7—H7B	108.9	H19A—C19—H19C	109.5
H7A—C7—H7B	107.7	H19B—C19—H19C	109.5
C17—C8—C7	113.08 (12)	C9—C20—H20A	109.5
C17—C8—C9	111.68 (11)	C9—C20—H20B	109.5
C7—C8—C9	114.33 (11)	H20A—C20—H20B	109.5
C17—C8—H8A	105.6	C9—C20—H20C	109.5
C7—C8—H8A	105.6	H20A—C20—H20C	109.5
C9—C8—H8A	105.6	H20B—C20—H20C	109.5
C20—C9—C10	114.15 (11)

C18—O1—C2—C1	−94.59 (13)	C2—C1—C10—C9	−121.36 (14)
C18—O1—C2—C3	23.98 (14)	C2—C1—C10—C5	13.4 (2)
C10—C1—C2—O1	64.85 (17)	C19—C5—C10—C9	−116.27 (13)
C10—C1—C2—C3	−48.58 (18)	C6—C5—C10—C9	2.04 (17)
O1—C2—C3—O3	−164.81 (11)	C4—C5—C10—C9	124.18 (13)
C1—C2—C3—O3	−46.95 (16)	C19—C5—C10—C1	110.25 (14)
O1—C2—C3—C4	−42.52 (13)	C6—C5—C10—C1	−131.43 (13)
C1—C2—C3—C4	75.34 (15)	C4—C5—C10—C1	−9.29 (18)
O3—C3—C4—O4	−77.80 (16)	C20—C9—C11—C12	124.47 (13)
C2—C3—C4—O4	161.55 (13)	C10—C9—C11—C12	−110.95 (14)
O3—C3—C4—C18	163.86 (12)	C8—C9—C11—C12	3.10 (18)
C2—C3—C4—C18	43.21 (13)	C17—O5—C12—C13	171.56 (12)
O3—C3—C4—C5	48.87 (17)	C17—O5—C12—C11	50.87 (15)
C2—C3—C4—C5	−71.78 (15)	C9—C11—C12—O5	−51.14 (16)
O4—C4—C5—C19	52.16 (16)	C9—C11—C12—C13	−168.04 (13)
C3—C4—C5—C19	−77.48 (15)	O5—C12—C13—C16	105.01 (16)
C18—C4—C5—C19	174.28 (12)	C11—C12—C13—C16	−136.03 (16)
O4—C4—C5—C6	−64.40 (15)	O5—C12—C13—C14	−76.91 (17)
C3—C4—C5—C6	165.96 (12)	C11—C12—C13—C14	42.1 (2)
C18—C4—C5—C6	57.71 (14)	C16—C13—C14—C15	0.54 (17)
O4—C4—C5—C10	170.36 (13)	C12—C13—C14—C15	−177.84 (14)
C3—C4—C5—C10	40.72 (17)	C13—C14—C15—O7	−0.09 (18)
C18—C4—C5—C10	−67.53 (15)	C16—O7—C15—C14	−0.40 (17)
C19—C5—C6—C7	73.55 (14)	C14—C13—C16—O7	−0.81 (17)
C4—C5—C6—C7	−168.95 (12)	C12—C13—C16—O7	177.62 (13)
C10—C5—C6—C7	−44.25 (16)	C15—O7—C16—C13	0.76 (16)
C5—C6—C7—C8	29.86 (17)	C12—O5—C17—O6	179.82 (13)
C6—C7—C8—C17	155.77 (13)	C12—O5—C17—C8	0.97 (18)
C6—C7—C8—C9	26.47 (18)	C7—C8—C17—O6	−2.4 (2)
C17—C8—C9—C20	−71.31 (15)	C9—C8—C17—O6	128.28 (16)
C7—C8—C9—C20	58.69 (15)	C7—C8—C17—O5	176.37 (12)
C17—C8—C9—C10	163.84 (13)	C9—C8—C17—O5	−52.99 (17)
C7—C8—C9—C10	−66.16 (16)	C2—O1—C18—O2	−174.62 (13)
C17—C8—C9—C11	47.30 (17)	C2—O1—C18—C4	5.10 (14)
C7—C8—C9—C11	177.30 (12)	O4—C4—C18—O2	27.2 (2)
C20—C9—C10—C1	61.69 (15)	C3—C4—C18—O2	148.19 (15)
C8—C9—C10—C1	−174.68 (12)	C5—C4—C18—O2	−93.50 (18)
C11—C9—C10—C1	−59.14 (16)	O4—C4—C18—O1	−152.46 (11)
C20—C9—C10—C5	−74.33 (14)	C3—C4—C18—O1	−31.50 (13)
C8—C9—C10—C5	49.30 (16)	C5—C4—C18—O1	86.81 (13)
C11—C9—C10—C5	164.85 (12)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1O3···O5ⁱ	0.86 (3)	2.54 (3)	3.1305 (15)	127 (2)
O4—H1O4···O6ⁱ	0.87 (3)	2.12 (3)	2.9708 (14)	165 (2)
C3—H3A···O5ⁱ	0.98	2.39	3.1295 (16)	131
C6—H6A···O2	0.97	2.43	3.1718 (19)	133
C8—H8A···O2ⁱⁱ	0.98	2.29	3.2113 (19)	157
C19—H19C···O3	0.96	2.31	2.9489 (18)	124
C20—H20B···O7ⁱⁱⁱ	0.96	2.53	3.4613 (18)	164

Symmetry codes: (i) x, y, z+1; (ii) −x+1, y−1/2, −z+1; (iii) −x, y+1/2, −z.

Experimental details

Crystal data
Chemical formula	C₂₀H₂₄O₇
M_r	376.39
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	100
a, b, c (Å)	7.0942 (2), 11.7149 (4), 10.1921 (3)
β (°)	90.805 (1)
V (Å³)	846.96 (5)
Z	2
Radiation type	Cu Kα
µ (mm⁻¹)	0.93
Crystal size (mm)	0.43 × 0.12 × 0.08

Data collection
Diffractometer	Bruker APEX DUO CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.692, 0.926
No. of measured, independent and observed [I > 2σ(I)] reflections	11247, 2645, 2641
R_int	0.018
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.066, 1.09
No. of reflections	2645
No. of parameters	254
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.19, −0.15
Absolute structure	Flack (1983), with 1098 Friedel pairs
Absolute structure parameter	0.03 (12)

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1O3···O5ⁱ	0.86 (3)	2.54 (3)	3.1305 (15)	127 (2)
O4—H1O4···O6ⁱ	0.87 (3)	2.12 (3)	2.9708 (14)	165 (2)
C3—H3A···O5ⁱ	0.98	2.39	3.1295 (16)	131
C6—H6A···O2	0.97	2.43	3.1718 (19)	133
C8—H8A···O2ⁱⁱ	0.98	2.29	3.2113 (19)	157
C19—H19C···O3	0.96	2.31	2.9489 (18)	124
C20—H20B···O7ⁱⁱⁱ	0.96	2.53	3.4613 (18)	164

Symmetry codes: (i) x, y, z+1; (ii) −x+1, y−1/2, −z+1; (iii) −x, y+1/2, −z.

Footnotes

‡Thomson Reuters ResearcherID: A-3561-2009.

§On PhD study leave from Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand.

¶Additional correspondence author, e-mail: suchada.c@psu.ac.th. Thomson Reuters ResearcherID: A-5085-2009.

Acknowledgements

AWS thanks the Universiti Sains Malaysia for a PhD Student Visiting Fellowship. SC thanks the Prince of Songkla University for financial support through the Crystal Materials Research Unit. The authors thank the Universiti Sains Malaysia for Research University Grant No. 1001/PFIZIK/811151.

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