2,2′-Dimethoxy-4,4′-[rel-(2R,3S)-2,3-di­methylbutane-1,4-diyl]diphenol

Salinas-Salazar, C.L.; Camacho-Corona, M. del R.; Bernès, S.; Waksman de Torres, N.

doi:10.1107/S1600536809017292

organic compounds

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ISSN: 2056-9890

Volume 65| Part 6| June 2009| Page o1279

doi:10.1107/S1600536809017292

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2,2′-Dimethoxy-4,4′-[rel-(2R,3S)-2,3-dimethylbutane-1,4-diyl]diphenol

Carmen L. Salinas-Salazar,^a María del Rayo Camacho-Corona,^a Sylvain Bernès ^b and Noemi Waksman de Torres ^c ^*

^aLaboratorio de Química de Productos Naturales, DEP Facultad de Ciencias Químicas, UANL, Monterrey, N.L., Mexico, ^bLaboratorio de Difracción de rayos X en Monocristales, DEP Facultad de Ciencias Químicas, UANL, Monterrey, N.L., Mexico, and ^cDepartamento de Química Analítica, Facultad de Medicina, UANL, Monterrey, N.L., Mexico
^*Correspondence e-mail: sylvain_bernes@Hotmail.com

(Received 18 February 2009; accepted 8 May 2009; online 14 May 2009)

The title molecule, C₂₀H₂₆O₄, commonly known as meso-dihydroguaiaretic acid, is a naturally occurring lignan extracted from Larrea tridentata and other plants. The molecule has a noncrystallographic inversion center situated at the midpoint of the central C—C bond, generating the meso stereoisomer. The central C—C—C—C alkyl chain displays an all-trans conformation, allowing an almost parallel arrangement of the benzene rings, which make a dihedral angle of 5.0 (3)°. Both hydroxy groups form weak O—H⋯O—H chains of hydrogen bonds along [100]. The resulting supramolecular structure is an undulating plane parallel to (010).

Related literature

For the extraction of the title molecule from Larrea tridentata, see: Waller & Gisvold (1945 ). For previous phytochemical characterizations, see: Gnabre et al. (1995 ); Konno et al. (1990 ); Tyler & Foster (1999 ). For the activity of this plant against Mycobacterium tuberculosis, see: Camacho-Corona et al. (2008 ).

Experimental

Crystal data

C₂₀H₂₆O₄
M_r = 330.41
Orthorhombic, P 2₁ 2₁ 2₁
a = 5.1355 (8) Å
b = 12.024 (2) Å
c = 30.158 (5) Å
V = 1862.2 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 298 K
0.50 × 0.40 × 0.18 mm

Data collection

Siemens P4 diffractometer
Absorption correction: none
3966 measured reflections
1937 independent reflections
1196 reflections with I > 2σ(I)
R_int = 0.159
2 standard reflections every 98 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.054
wR(F²) = 0.139
S = 1.00
1937 reflections
227 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O14ⁱ	0.84 (2)	2.15 (3)	2.908 (6)	149 (5)
O14—H14⋯O2ⁱⁱ	0.86 (2)	2.35 (4)	3.030 (5)	137 (5)
Symmetry codes: (i) $[-x+{\script{3\over 2}}, -y+1, z-{\script{1\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, -y+1, z+{\script{1\over 2}}]$ .

Data collection: XSCANS (Siemens, 1996 ); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809017292/is2391sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809017292/is2391Isup2.hkl

checkCIF report

Comment top

Larrea tridentata, also known as gobernadora, hediondilla, greasewood, chaparral or creosote bush, is a shrubby plant belonging to the family of Zygophyllaceae, which grows in some areas of the desert southwest in the United States of America and Northern Mexico. Tuberculosis, cancer, menstrual pains, and diabetes treatment are among the indications listed for chaparral (Tyler & Foster, 1999). For instance, L. tridentata has been shown to be active against Mycobacterium tuberculosis, with a minimum inhibitory concentration of 200 µg/ml (Camacho-Corona et al., 2008). We are currently working on the full characterization of the main active compounds found in the chloroform extract of that plant.

Previous phytochemical studies carried out on L. tridentata showed that it contains a series of lignans (Konno et al., 1990; Gnabre et al., 1995), one of which being the title molecule. This molecule, commonly called meso-dihydroguaiaretic acid, crystallizes in the space group P2₁2₁2₁, with the molecule placed on a non-crystallographic inversion center (Fig. 1). As a consequence, the relative stereochemistry for chiral C atoms is (R,S). The central aliphatic chain is stabilized in an all-trans conformation, and peripheral benzene rings are almost parallel, making a dihedral angle of 5.0 (3)°.

The crystal structure features weak O—H···O hydrogen bonds involving all hydroxy groups. Infinite chains are formed along the short axis [100], with OH functionalities serving both as donor and acceptor groups. As a result, a two-dimensional supramolecular framework is formed, parallel to plane (010) in the crystal (Fig. 2).

Related literature top

For the extraction of the title molecule from Larrea tridentata, see: Waller & Gisvold (1945). For previous phytochemical characterizations, see: Gnabre et al. (1995); Konno et al. (1990); Tyler & Foster (1999). For the activity of this plant against Mycobacterium tuberculosis, see: Camacho-Corona et al. (2008).

Experimental top

Aerial parts of L. tridentata were collected in April 2006, at Galeana (Nuevo León, Mexico) and identified by Biologist Marcela González Álvarez. A voucher specimen (024772) is available in the botanic department of the Biology Faculty (UNL, Monterrey, Mexico). After grinding, the dry material (500 g) was placed in an Erlenmeyer vessel filled with hexane (1 l) and left at 298 K for 24 h. The preparation was then filtered and the resulting vegetal material soaked with chloroform for 72 h. The chloroform extract was then filtered and concentrated in vacuo, affording 89 g of extracts. The chloroform extract (80 g) was chromatographed on silica-gel (1600 g) using mixtures of chloroform/ethanol as eluent, giving 13 fractions. The third fraction, eluted with pure CHCl₃, afforded colorless crystals, which were separated by filtration. After recrystallization from hexane/ethyl acetate (80:20), pure meso-dihydroguaiaretic acid was obtained (730 mg, m.p. 360 K). Spectroscopic data are consistent with the X-ray structure (see archived CIF). The full characterization by NMR also allowed to confirm that this lignan was early isolated by Waller & Gisvold (1945) from the same plant.

Computing details top

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS (Siemens, 1996); data reduction: XSCANS (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The title compound, with displacement ellipsoids at the 30% probability level.
	Fig. 2. A part of the crystal structure of the title compound. For H atoms, only hydroxy H atoms have been retained, which are engaged in hydrogen bonding (dashed bonds).

2,2'-Dimethoxy-4,4'-[rel-(2R,3S)-2,3-dimethylbutane- 1,4-diyl]diphenol top

Crystal data top

C₂₀H₂₆O₄	D_x = 1.179 Mg m⁻³
M_r = 330.41	Melting point: 360 K
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 54 reflections
a = 5.1355 (8) Å	θ = 4.4–11.0°
b = 12.024 (2) Å	µ = 0.08 mm⁻¹
c = 30.158 (5) Å	T = 298 K
V = 1862.2 (5) Å³	Plate, colourless
Z = 4	0.50 × 0.40 × 0.18 mm
F(000) = 712

Data collection top

Siemens P4 diffractometer	R_int = 0.159
Radiation source: fine-focus sealed tube	θ_max = 25.0°, θ_min = 1.8°
Graphite monochromator	h = −6→6
ω scans	k = −14→1
3966 measured reflections	l = −35→1
1937 independent reflections	2 standard reflections every 98 reflections
1196 reflections with I > 2σ(I)	intensity decay: 1%

Refinement top

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.139	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ²(F_o²) + (0.0472P)²] where P = (F_o² + 2F_c²)/3
1937 reflections	(Δ/σ)_max < 0.001
227 parameters	Δρ_max = 0.18 e Å⁻³
2 restraints	Δρ_min = −0.17 e Å⁻³
0 constraints

Crystal data top

C₂₀H₂₆O₄	V = 1862.2 (5) Å³
M_r = 330.41	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 5.1355 (8) Å	µ = 0.08 mm⁻¹
b = 12.024 (2) Å	T = 298 K
c = 30.158 (5) Å	0.50 × 0.40 × 0.18 mm

Data collection top

Siemens P4 diffractometer	R_int = 0.159
3966 measured reflections	2 standard reflections every 98 reflections
1937 independent reflections	intensity decay: 1%
1196 reflections with I > 2σ(I)

Refinement top

R[F² > 2σ(F²)] = 0.054	2 restraints
wR(F²) = 0.139	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	Δρ_max = 0.18 e Å⁻³
1937 reflections	Δρ_min = −0.17 e Å⁻³
227 parameters

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

	x	y	z	U_iso*/U_eq
O1	0.7382 (7)	0.4677 (2)	0.26965 (7)	0.0629 (8)
O2	0.4317 (8)	0.3034 (3)	0.24222 (9)	0.0732 (10)
H2	0.580 (6)	0.327 (5)	0.2350 (16)	0.110*
O13	0.2881 (7)	0.5103 (3)	0.67472 (8)	0.0703 (9)
O14	0.5820 (8)	0.6849 (3)	0.69302 (8)	0.0712 (10)
H14	0.451 (8)	0.650 (4)	0.7037 (14)	0.107*
C1	0.5599 (9)	0.4296 (3)	0.29987 (11)	0.0493 (11)
C2	0.4047 (9)	0.3442 (3)	0.28494 (10)	0.0505 (11)
C3	0.2159 (10)	0.2992 (3)	0.31135 (13)	0.0614 (12)
H3A	0.1110	0.2419	0.3009	0.074*
C4	0.1827 (10)	0.3406 (4)	0.35425 (11)	0.0619 (12)
H4A	0.0536	0.3109	0.3723	0.074*
C5	0.3379 (9)	0.4242 (4)	0.36995 (11)	0.0540 (11)
C6	0.5250 (10)	0.4695 (3)	0.34251 (11)	0.0541 (11)
H6A	0.6286	0.5275	0.3528	0.065*
C7	0.3030 (9)	0.4706 (4)	0.41668 (11)	0.0676 (13)
H7A	0.1446	0.4400	0.4292	0.081*
H7B	0.2811	0.5506	0.4147	0.081*
C8	0.5292 (10)	0.4456 (3)	0.44808 (11)	0.0516 (11)
H8B	0.6859	0.4789	0.4352	0.062*
C9	0.4850 (9)	0.5012 (3)	0.49355 (10)	0.0494 (10)
H9A	0.3223	0.4712	0.5056	0.059*
C10	0.7010 (10)	0.4725 (3)	0.52650 (10)	0.0656 (14)
H10B	0.7041	0.3925	0.5306	0.079*
H10C	0.8668	0.4941	0.5137	0.079*
C11	0.6747 (9)	0.5273 (3)	0.57162 (11)	0.0556 (12)
C12	0.4889 (9)	0.4893 (3)	0.60132 (11)	0.0549 (11)
H12C	0.3845	0.4288	0.5941	0.066*
C13	0.4594 (10)	0.5421 (3)	0.64204 (11)	0.0518 (11)
C14	0.6091 (10)	0.6318 (3)	0.65279 (11)	0.0532 (11)
C15	0.7953 (11)	0.6697 (3)	0.62395 (12)	0.0658 (12)
H15B	0.8990	0.7304	0.6313	0.079*
C16	0.8261 (11)	0.6157 (4)	0.58344 (12)	0.0634 (13)
H16A	0.9535	0.6406	0.5639	0.076*
C17	0.9001 (11)	0.5584 (4)	0.28192 (12)	0.0683 (13)
H17B	1.0187	0.5746	0.2582	0.102*
H17C	0.9968	0.5393	0.3081	0.102*
H17D	0.7943	0.6225	0.2878	0.102*
C18	0.5765 (13)	0.3217 (3)	0.45129 (11)	0.0801 (16)
H18C	0.5897	0.2908	0.4220	0.120*
H18D	0.4342	0.2873	0.4667	0.120*
H18E	0.7355	0.3083	0.4672	0.120*
C19	0.4509 (15)	0.6260 (3)	0.48960 (12)	0.0877 (18)
H19D	0.4239	0.6573	0.5185	0.131*
H19E	0.3030	0.6419	0.4712	0.131*
H19F	0.6043	0.6580	0.4766	0.131*
C20	0.1181 (10)	0.4196 (4)	0.66747 (13)	0.0668 (13)
H20B	0.0149	0.4072	0.6936	0.100*
H20C	0.2181	0.3541	0.6611	0.100*
H20D	0.0058	0.4358	0.6429	0.100*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.069 (2)	0.0660 (18)	0.0537 (14)	−0.0157 (19)	0.0004 (17)	−0.0018 (13)
O2	0.084 (3)	0.086 (2)	0.0494 (16)	−0.026 (2)	−0.0004 (17)	−0.0086 (14)
O13	0.078 (2)	0.082 (2)	0.0511 (14)	−0.022 (2)	0.0105 (16)	−0.0045 (14)
O14	0.090 (3)	0.070 (2)	0.0543 (16)	−0.020 (2)	0.0049 (18)	−0.0109 (14)
C1	0.049 (3)	0.054 (2)	0.045 (2)	−0.002 (2)	−0.008 (2)	0.0090 (18)
C2	0.055 (3)	0.053 (2)	0.044 (2)	0.001 (3)	−0.008 (2)	0.0010 (18)
C3	0.057 (3)	0.064 (3)	0.063 (2)	−0.011 (3)	−0.008 (2)	0.004 (2)
C4	0.049 (3)	0.080 (3)	0.056 (2)	−0.006 (3)	−0.007 (2)	0.008 (2)
C5	0.046 (3)	0.069 (3)	0.047 (2)	0.013 (3)	−0.005 (2)	−0.002 (2)
C6	0.049 (3)	0.061 (3)	0.052 (2)	0.002 (3)	−0.007 (2)	0.0010 (19)
C7	0.050 (3)	0.101 (3)	0.052 (2)	0.011 (3)	−0.004 (2)	−0.006 (2)
C8	0.047 (3)	0.063 (3)	0.0448 (19)	−0.004 (3)	0.008 (2)	0.0034 (18)
C9	0.045 (2)	0.058 (2)	0.0451 (19)	0.003 (3)	0.004 (2)	0.0060 (17)
C10	0.066 (3)	0.084 (3)	0.047 (2)	0.015 (3)	0.001 (2)	0.000 (2)
C11	0.055 (3)	0.067 (3)	0.045 (2)	0.010 (3)	−0.004 (2)	0.005 (2)
C12	0.059 (3)	0.055 (2)	0.051 (2)	0.001 (3)	−0.009 (2)	−0.0018 (19)
C13	0.052 (3)	0.059 (2)	0.044 (2)	0.002 (3)	−0.003 (2)	0.0064 (19)
C14	0.067 (3)	0.045 (2)	0.048 (2)	0.002 (3)	−0.002 (2)	0.0045 (19)
C15	0.075 (3)	0.063 (3)	0.060 (2)	−0.010 (3)	−0.001 (3)	0.009 (2)
C16	0.064 (3)	0.076 (3)	0.051 (2)	−0.007 (3)	0.006 (2)	0.013 (2)
C17	0.072 (4)	0.067 (3)	0.066 (2)	−0.016 (3)	−0.007 (3)	0.012 (2)
C18	0.116 (5)	0.066 (3)	0.058 (2)	0.016 (4)	0.002 (3)	−0.004 (2)
C19	0.122 (5)	0.068 (3)	0.073 (3)	0.025 (4)	−0.026 (3)	−0.005 (2)
C20	0.059 (3)	0.069 (3)	0.073 (3)	−0.014 (3)	−0.001 (3)	0.008 (2)

Geometric parameters (Å, º) top

O1—C1	1.371 (5)	C9—H9A	0.9800
O1—C17	1.420 (5)	C10—C11	1.518 (5)
O2—C2	1.386 (5)	C10—H10B	0.9700
O2—H2	0.84 (2)	C10—H10C	0.9700
O13—C13	1.376 (5)	C11—C16	1.364 (6)
O13—C20	1.414 (5)	C11—C12	1.386 (6)
O14—C14	1.378 (5)	C12—C13	1.391 (5)
O14—H14	0.86 (2)	C12—H12C	0.9300
C1—C2	1.375 (6)	C13—C14	1.363 (6)
C1—C6	1.384 (5)	C14—C15	1.371 (6)
C2—C3	1.367 (6)	C15—C16	1.393 (5)
C3—C4	1.396 (5)	C15—H15B	0.9300
C3—H3A	0.9300	C16—H16A	0.9300
C4—C5	1.368 (6)	C17—H17B	0.9600
C4—H4A	0.9300	C17—H17C	0.9600
C5—C6	1.380 (6)	C17—H17D	0.9600
C5—C7	1.526 (5)	C18—H18C	0.9600
C6—H6A	0.9300	C18—H18D	0.9600
C7—C8	1.529 (6)	C18—H18E	0.9600
C7—H7A	0.9700	C19—H19D	0.9600
C7—H7B	0.9700	C19—H19E	0.9600
C8—C18	1.512 (6)	C19—H19F	0.9600
C8—C9	1.542 (5)	C20—H20B	0.9600
C8—H8B	0.9800	C20—H20C	0.9600
C9—C19	1.516 (5)	C20—H20D	0.9600
C9—C10	1.529 (6)

C1—O1—C17	118.3 (3)	C9—C10—H10C	108.6
C2—O2—H2	102 (4)	H10B—C10—H10C	107.5
C13—O13—C20	119.9 (3)	C16—C11—C12	118.7 (4)
C14—O14—H14	101 (3)	C16—C11—C10	121.4 (4)
O1—C1—C2	114.8 (3)	C12—C11—C10	119.8 (4)
O1—C1—C6	126.0 (4)	C11—C12—C13	119.6 (4)
C2—C1—C6	119.2 (4)	C11—C12—H12C	120.2
C3—C2—C1	121.1 (4)	C13—C12—H12C	120.2
C3—C2—O2	118.2 (4)	C14—C13—O13	114.2 (3)
C1—C2—O2	120.7 (4)	C14—C13—C12	120.7 (4)
C2—C3—C4	119.0 (4)	O13—C13—C12	125.1 (4)
C2—C3—H3A	120.5	C13—C14—C15	120.4 (4)
C4—C3—H3A	120.5	C13—C14—O14	121.3 (4)
C5—C4—C3	120.8 (4)	C15—C14—O14	118.3 (4)
C5—C4—H4A	119.6	C14—C15—C16	118.7 (4)
C3—C4—H4A	119.6	C14—C15—H15B	120.6
C4—C5—C6	119.2 (3)	C16—C15—H15B	120.6
C4—C5—C7	121.3 (4)	C11—C16—C15	121.8 (4)
C6—C5—C7	119.4 (4)	C11—C16—H16A	119.1
C5—C6—C1	120.7 (4)	C15—C16—H16A	119.1
C5—C6—H6A	119.7	O1—C17—H17B	109.5
C1—C6—H6A	119.7	O1—C17—H17C	109.5
C5—C7—C8	114.3 (4)	H17B—C17—H17C	109.5
C5—C7—H7A	108.7	O1—C17—H17D	109.5
C8—C7—H7A	108.7	H17B—C17—H17D	109.5
C5—C7—H7B	108.7	H17C—C17—H17D	109.5
C8—C7—H7B	108.7	C8—C18—H18C	109.5
H7A—C7—H7B	107.6	C8—C18—H18D	109.5
C18—C8—C7	110.8 (4)	H18C—C18—H18D	109.5
C18—C8—C9	113.2 (3)	C8—C18—H18E	109.5
C7—C8—C9	110.7 (4)	H18C—C18—H18E	109.5
C18—C8—H8B	107.3	H18D—C18—H18E	109.5
C7—C8—H8B	107.3	C9—C19—H19D	109.5
C9—C8—H8B	107.3	C9—C19—H19E	109.5
C19—C9—C10	111.0 (4)	H19D—C19—H19E	109.5
C19—C9—C8	112.1 (3)	C9—C19—H19F	109.5
C10—C9—C8	111.9 (3)	H19D—C19—H19F	109.5
C19—C9—H9A	107.2	H19E—C19—H19F	109.5
C10—C9—H9A	107.2	O13—C20—H20B	109.5
C8—C9—H9A	107.2	O13—C20—H20C	109.5
C11—C10—C9	114.9 (4)	H20B—C20—H20C	109.5
C11—C10—H10B	108.6	O13—C20—H20D	109.5
C9—C10—H10B	108.6	H20B—C20—H20D	109.5
C11—C10—H10C	108.6	H20C—C20—H20D	109.5

C17—O1—C1—C2	177.9 (4)	C18—C8—C9—C10	51.8 (6)
C17—O1—C1—C6	−1.7 (6)	C7—C8—C9—C10	176.9 (3)
O1—C1—C2—C3	−179.1 (4)	C19—C9—C10—C11	52.1 (5)
C6—C1—C2—C3	0.6 (6)	C8—C9—C10—C11	178.2 (4)
O1—C1—C2—O2	−0.6 (6)	C9—C10—C11—C16	−104.1 (5)
C6—C1—C2—O2	179.0 (4)	C9—C10—C11—C12	74.2 (5)
C1—C2—C3—C4	−0.5 (6)	C16—C11—C12—C13	0.5 (6)
O2—C2—C3—C4	−178.9 (4)	C10—C11—C12—C13	−177.8 (4)
C2—C3—C4—C5	−0.6 (6)	C20—O13—C13—C14	178.9 (4)
C3—C4—C5—C6	1.5 (6)	C20—O13—C13—C12	−2.3 (6)
C3—C4—C5—C7	179.7 (4)	C11—C12—C13—C14	0.8 (6)
C4—C5—C6—C1	−1.4 (6)	C11—C12—C13—O13	−177.9 (4)
C7—C5—C6—C1	−179.6 (4)	O13—C13—C14—C15	177.5 (4)
O1—C1—C6—C5	179.9 (4)	C12—C13—C14—C15	−1.5 (6)
C2—C1—C6—C5	0.3 (6)	O13—C13—C14—O14	−1.1 (6)
C4—C5—C7—C8	112.6 (5)	C12—C13—C14—O14	−180.0 (4)
C6—C5—C7—C8	−69.3 (5)	C13—C14—C15—C16	0.7 (7)
C5—C7—C8—C18	−56.9 (5)	O14—C14—C15—C16	179.2 (4)
C5—C7—C8—C9	176.7 (3)	C12—C11—C16—C15	−1.3 (6)
C18—C8—C9—C19	177.3 (5)	C10—C11—C16—C15	177.0 (4)
C7—C8—C9—C19	−57.6 (6)	C14—C15—C16—C11	0.7 (7)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O14ⁱ	0.84 (2)	2.15 (3)	2.908 (6)	149 (5)
O14—H14···O2ⁱⁱ	0.86 (2)	2.35 (4)	3.030 (5)	137 (5)
O2—H2···O1	0.84 (2)	2.14 (5)	2.658 (4)	119 (5)
O14—H14···O13	0.86 (2)	2.07 (4)	2.644 (5)	124 (4)

Symmetry codes: (i) −x+3/2, −y+1, z−1/2; (ii) −x+1/2, −y+1, z+1/2.

Experimental details

Crystal data
Chemical formula	C₂₀H₂₆O₄
M_r	330.41
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	298
a, b, c (Å)	5.1355 (8), 12.024 (2), 30.158 (5)
V (Å³)	1862.2 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.50 × 0.40 × 0.18

Data collection
Diffractometer	Siemens P4 diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	3966, 1937, 1196
R_int	0.159
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.054, 0.139, 1.00
No. of reflections	1937
No. of parameters	227
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.17

Computer programs: XSCANS (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and Mercury (Macrae et al., 2006).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O14ⁱ	0.84 (2)	2.15 (3)	2.908 (6)	149 (5)
O14—H14···O2ⁱⁱ	0.86 (2)	2.35 (4)	3.030 (5)	137 (5)

Symmetry codes: (i) −x+3/2, −y+1, z−1/2; (ii) −x+1/2, −y+1, z+1/2.

Acknowledgements

We thank Dr Veronica Rivas Galindo for running the NMR spectra of lignan. We also acknowledge PAICyT for financial support (grant No. SA1417-06).

References

Camacho-Corona, M. D. R., Ramírez-Cabrera, M. A., Santiago, O. G., Garza-González, E., Palacios, I. P. & Luna-Herrera, J. (2008). Phytother. Res. 22, 82–85. Web of Science CrossRef PubMed Google Scholar
Gnabre, J., Huang, R. C. C., Bates, R. B., Burns, J. J., Caldera, S., Malcomson, M. E. & McClure, K. J. (1995). Tetrahedron, 51, 12203–12210. CrossRef CAS Web of Science Google Scholar
Konno, C., Lu, Z. Z., Xue, H. Z., Erdelmeier, C. A. J., Meksuriyen, D., Che, C. T., Cordell, G. A., Soejarto, D. D., Waller, D. P. & Fong, H. H. S. (1990). J. Nat. Prod. 53, 396–406. CrossRef CAS PubMed Web of Science Google Scholar
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
Tyler, V. & Foster, S. (1999). Tyler's Honest Herbal: a Sensible Guide to the Use of Herbs and Related Remedies, pp. 109–111. New-York: Haworth Herbal Press. Google Scholar
Waller, C. W. & Gisvold, O. (1945). J. Am. Pharm. Assoc. 34, 78–81. CrossRef CAS Google Scholar