Vieillardiixanthone B.

THE TITLE COMPOUND [SYSTEMATIC NAME: 1,5-dihydr-oxy-3,6-dimeth-oxy-4-(2-methyl-but-3-en-2-yl)-9H-xanthen-9-one], C(20)H(20)O(6), is a xanthone, which was isolated from the roots of Cratoxylum formosum ssp. pruniflorum. The three rings in the mol-ecule are approximately coplanar, with an r.m.s. deviation of 0.0372 (2) Å for the plane through the 14 non-H atoms. The O atoms of the two hydr-oxy substituents also lie close to this plane with deviations of 0.0669 (2) and 0.1122 (2) Å, respectively. The 1,1-dimethyl-2-propenyl substituent is in a (-)-anti-clinal conformation. Intra-molecular O-H⋯O hydrogen bonds generate S(5) and S(6) ring motifs. In the crystal, mol-ecules are linked into infinite chains along [010] by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. π-π inter-actions with centroid-centroid distances of 3.6172 (10) and 3.6815 (10) Å are also observed.

Related literature

For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶). For background to xanthones and their biological activity, see: Boonnak, Karalai et al. (2006 ▶, 2007 ▶, 2009 ▶); Hay et al. (2008 ▶). For a related structure, see: Boonnak, Chantrapromma & Fun (2006 ▶). For the stability of the temperature controller used in the data collection, see Cosier & Glazer, (1986 ▶).

Experimental

Crystal data

C20H20O6

M = 356.36

Monoclinic,

a = 12.1500 (4) Å

b = 14.7396 (4) Å

c = 9.5177 (3) Å

β = 90.208 (2)°

V = 1704.48 (9) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 100 K

0.50 × 0.23 × 0.22 mm

Data collection

Bruker APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.951, T max = 0.978

37868 measured reflections

3906 independent reflections

2682 reflections with I > 2σ(I)

R int = 0.071

Refinement

R[F 2 > 2σ(F 2)] = 0.054

wR(F 2) = 0.133

S = 1.03

3906 reflections

259 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.27 e Å−3

Δρmin = −0.27 e Å−3

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); 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 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810007026/sj2732sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810007026/sj2732Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C20H20O6	F(000) = 752
Mr = 356.36	Dx = 1.389 Mg m−3
Monoclinic, P21/c	Melting point = 486–488 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 12.1500 (4) Å	Cell parameters from 3906 reflections
b = 14.7396 (4) Å	θ = 2.2–27.5°
c = 9.5177 (3) Å	µ = 0.10 mm−1
β = 90.208 (2)°	T = 100 K
V = 1704.48 (9) Å3	Block, yellow
Z = 4	0.50 × 0.23 × 0.22 mm

Bruker APEXII CCD area-detector diffractometer	3906 independent reflections
Radiation source: sealed tube	2682 reflections with I > 2σ(I)
graphite	Rint = 0.071
φ and ω scans	θmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −15→15
Tmin = 0.951, Tmax = 0.978	k = −19→19
37868 measured reflections	l = −12→12

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) = 0.133	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ2(Fo2) + (0.0609P)2 + 0.5536P] where P = (Fo2 + 2Fc2)/3
3906 reflections	(Δ/σ)max < 0.001
259 parameters	Δρmax = 0.27 e Å−3
0 restraints	Δρmin = −0.27 e Å−3

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.

	x	y	z	Uiso*/Ueq
O1	0.35090 (10)	0.13014 (8)	0.63535 (13)	0.0187 (3)
O2	0.37354 (10)	0.40673 (8)	0.61270 (13)	0.0207 (3)
O3	0.21931 (11)	0.40714 (8)	0.42914 (14)	0.0230 (3)
H1O3	0.278 (2)	0.4208 (18)	0.491 (3)	0.055 (8)*
O4	0.07417 (11)	0.12110 (9)	0.29203 (14)	0.0257 (3)
O5	0.46803 (11)	0.02998 (8)	0.80738 (14)	0.0202 (3)
H1O5	0.522 (2)	0.0062 (16)	0.847 (2)	0.038 (7)*
O6	0.62914 (11)	0.10303 (8)	0.96779 (14)	0.0222 (3)
C1	0.21969 (15)	0.31542 (12)	0.43964 (19)	0.0186 (4)
C2	0.14722 (15)	0.26604 (12)	0.35834 (19)	0.0195 (4)
H2A	0.0986	0.2956	0.2981	0.023*
C3	0.14717 (15)	0.17086 (12)	0.36683 (19)	0.0187 (4)
C4	0.22012 (14)	0.12173 (12)	0.45343 (19)	0.0176 (4)
C5	0.48867 (15)	0.12058 (11)	0.80499 (19)	0.0174 (4)
C6	0.56984 (15)	0.16161 (12)	0.88664 (19)	0.0188 (4)
C7	0.58547 (16)	0.25558 (12)	0.8834 (2)	0.0201 (4)
H7A	0.6400	0.2822	0.9385	0.024*
C8	0.51960 (15)	0.30887 (12)	0.79793 (19)	0.0202 (4)
H8A	0.5291	0.3715	0.7972	0.024*
C9	0.36821 (15)	0.32157 (11)	0.62009 (18)	0.0171 (4)
C10	0.29140 (14)	0.27097 (11)	0.53441 (19)	0.0168 (4)
C11	0.28714 (14)	0.17552 (12)	0.53963 (19)	0.0166 (4)
C12	0.42547 (14)	0.17531 (12)	0.71676 (18)	0.0166 (4)
C13	0.43899 (15)	0.26940 (11)	0.71284 (19)	0.0174 (4)
C14	0.00024 (16)	0.16425 (14)	0.1967 (2)	0.0265 (5)
H14A	−0.0397	0.1190	0.1449	0.040*
H14B	0.0411	0.2015	0.1328	0.040*
H14C	−0.0505	0.2013	0.2483	0.040*
C15	0.22616 (15)	0.01618 (12)	0.45818 (19)	0.0184 (4)
C16	0.34762 (16)	−0.01610 (12)	0.4569 (2)	0.0221 (4)
H16A	0.3505	−0.0789	0.4305	0.033*
H16B	0.3791	−0.0087	0.5488	0.033*
H16C	0.3885	0.0193	0.3904	0.033*
C17	0.16997 (17)	−0.01792 (12)	0.5923 (2)	0.0250 (4)
H17A	0.0927	−0.0044	0.5879	0.038*
H17B	0.2020	0.0116	0.6726	0.038*
H17C	0.1801	−0.0823	0.6004	0.038*
C18	0.17864 (16)	−0.02757 (12)	0.3267 (2)	0.0223 (4)
H18	0.2133 (17)	−0.0069 (14)	0.240 (2)	0.028 (6)*
C19	0.10821 (18)	−0.09584 (14)	0.3216 (3)	0.0316 (5)
H19B	0.0844 (17)	−0.1203 (14)	0.231 (2)	0.030 (6)*
H19A	0.0703 (18)	−0.1196 (15)	0.407 (2)	0.038 (6)*
C20	0.72165 (16)	0.13735 (13)	1.0432 (2)	0.0256 (5)
H20A	0.7565	0.0888	1.0937	0.038*
H20B	0.6977	0.1830	1.1082	0.038*
H20C	0.7731	0.1634	0.9784	0.038*

	U11	U22	U33	U12	U13	U23
O1	0.0254 (7)	0.0110 (6)	0.0195 (7)	−0.0006 (5)	−0.0059 (6)	0.0008 (5)
O2	0.0294 (7)	0.0091 (6)	0.0236 (7)	−0.0007 (5)	−0.0048 (6)	0.0011 (5)
O3	0.0304 (8)	0.0116 (6)	0.0270 (8)	0.0018 (5)	−0.0076 (6)	0.0025 (6)
O4	0.0277 (8)	0.0176 (7)	0.0317 (8)	−0.0013 (5)	−0.0153 (6)	0.0021 (6)
O5	0.0266 (8)	0.0089 (6)	0.0251 (7)	−0.0005 (5)	−0.0072 (6)	0.0011 (5)
O6	0.0281 (7)	0.0123 (6)	0.0259 (7)	−0.0004 (5)	−0.0115 (6)	0.0017 (5)
C1	0.0246 (10)	0.0113 (8)	0.0199 (10)	0.0003 (7)	0.0024 (8)	0.0016 (7)
C2	0.0219 (10)	0.0171 (9)	0.0195 (10)	0.0023 (7)	−0.0041 (8)	0.0029 (7)
C3	0.0220 (10)	0.0165 (9)	0.0177 (9)	−0.0014 (7)	−0.0019 (8)	0.0002 (7)
C4	0.0214 (10)	0.0131 (8)	0.0183 (9)	0.0001 (7)	0.0005 (8)	0.0013 (7)
C5	0.0233 (10)	0.0100 (8)	0.0188 (9)	0.0000 (7)	0.0004 (8)	−0.0003 (7)
C6	0.0229 (10)	0.0150 (9)	0.0185 (10)	0.0016 (7)	−0.0042 (8)	0.0008 (7)
C7	0.0254 (10)	0.0130 (9)	0.0219 (10)	−0.0024 (7)	−0.0048 (8)	−0.0023 (8)
C8	0.0280 (10)	0.0100 (8)	0.0225 (10)	0.0003 (7)	−0.0009 (8)	−0.0002 (7)
C9	0.0225 (10)	0.0125 (8)	0.0164 (9)	0.0002 (7)	0.0017 (8)	−0.0001 (7)
C10	0.0210 (9)	0.0117 (8)	0.0177 (9)	0.0007 (7)	−0.0011 (8)	−0.0007 (7)
C11	0.0199 (9)	0.0132 (8)	0.0167 (9)	0.0020 (7)	−0.0011 (8)	0.0024 (7)
C12	0.0195 (9)	0.0141 (9)	0.0162 (9)	−0.0010 (7)	−0.0022 (7)	−0.0023 (7)
C13	0.0228 (10)	0.0122 (8)	0.0172 (9)	−0.0003 (7)	−0.0008 (8)	−0.0010 (7)
C14	0.0279 (11)	0.0258 (10)	0.0256 (11)	−0.0033 (8)	−0.0101 (9)	0.0040 (9)
C15	0.0234 (10)	0.0118 (8)	0.0201 (10)	−0.0012 (7)	−0.0023 (8)	0.0008 (7)
C16	0.0289 (11)	0.0115 (8)	0.0258 (10)	−0.0002 (7)	−0.0029 (8)	−0.0021 (8)
C17	0.0343 (11)	0.0147 (9)	0.0262 (10)	−0.0024 (8)	0.0029 (9)	0.0020 (8)
C18	0.0259 (10)	0.0155 (9)	0.0255 (10)	0.0021 (8)	−0.0032 (9)	−0.0012 (8)
C19	0.0346 (12)	0.0218 (10)	0.0384 (13)	−0.0040 (9)	−0.0087 (11)	−0.0066 (10)
C20	0.0266 (11)	0.0205 (10)	0.0295 (11)	0.0007 (8)	−0.0121 (9)	−0.0006 (8)

O1—C12	1.364 (2)	C8—H8A	0.9300
O1—C11	1.368 (2)	C9—C10	1.445 (2)
O2—C9	1.259 (2)	C9—C13	1.451 (2)
O3—C1	1.356 (2)	C10—C11	1.409 (2)
O3—H1O3	0.94 (3)	C12—C13	1.397 (2)
O4—C3	1.352 (2)	C14—H14A	0.9600
O4—C14	1.424 (2)	C14—H14B	0.9600
O5—C5	1.359 (2)	C14—H14C	0.9600
O5—H1O5	0.83 (3)	C15—C18	1.520 (3)
O6—C6	1.363 (2)	C15—C17	1.535 (3)
O6—C20	1.424 (2)	C15—C16	1.551 (3)
C1—C2	1.378 (3)	C16—H16A	0.9600
C1—C10	1.413 (2)	C16—H16B	0.9600
C2—C3	1.405 (2)	C16—H16C	0.9600
C2—H2A	0.9300	C17—H17A	0.9600
C3—C4	1.409 (2)	C17—H17B	0.9600
C4—C11	1.400 (2)	C17—H17C	0.9600
C4—C15	1.558 (2)	C18—C19	1.322 (3)
C5—C6	1.392 (3)	C18—H18	0.97 (2)
C5—C12	1.393 (2)	C19—H19B	0.98 (2)
C6—C7	1.398 (2)	C19—H19A	1.00 (2)
C7—C8	1.383 (3)	C20—H20A	0.9600
C7—H7A	0.9300	C20—H20B	0.9600
C8—C13	1.396 (3)	C20—H20C	0.9600
C12—O1—C11	120.87 (13)	C5—C12—C13	121.75 (16)
C1—O3—H1O3	99.5 (16)	C8—C13—C12	118.73 (16)
C3—O4—C14	120.28 (15)	C8—C13—C9	123.04 (16)
C5—O5—H1O5	106.1 (16)	C12—C13—C9	118.23 (16)
C6—O6—C20	118.38 (13)	O4—C14—H14A	109.5
O3—C1—C2	118.90 (16)	O4—C14—H14B	109.5
O3—C1—C10	120.77 (16)	H14A—C14—H14B	109.5
C2—C1—C10	120.32 (16)	O4—C14—H14C	109.5
C1—C2—C3	119.70 (17)	H14A—C14—H14C	109.5
C1—C2—H2A	120.2	H14B—C14—H14C	109.5
C3—C2—H2A	120.2	C18—C15—C17	112.15 (15)
O4—C3—C2	120.79 (16)	C18—C15—C16	102.82 (14)
O4—C3—C4	116.07 (15)	C17—C15—C16	109.42 (15)
C2—C3—C4	123.13 (17)	C18—C15—C4	112.47 (15)
C11—C4—C3	114.54 (16)	C17—C15—C4	109.27 (14)
C11—C4—C15	121.41 (15)	C16—C15—C4	110.54 (14)
C3—C4—C15	124.04 (16)	C15—C16—H16A	109.5
O5—C5—C6	123.24 (16)	C15—C16—H16B	109.5
O5—C5—C12	118.53 (16)	H16A—C16—H16B	109.5
C6—C5—C12	118.23 (16)	C15—C16—H16C	109.5
O6—C6—C5	114.41 (15)	H16A—C16—H16C	109.5
O6—C6—C7	124.65 (16)	H16B—C16—H16C	109.5
C5—C6—C7	120.93 (17)	C15—C17—H17A	109.5
C8—C7—C6	119.81 (17)	C15—C17—H17B	109.5
C8—C7—H7A	120.1	H17A—C17—H17B	109.5
C6—C7—H7A	120.1	C15—C17—H17C	109.5
C7—C8—C13	120.51 (16)	H17A—C17—H17C	109.5
C7—C8—H8A	119.7	H17B—C17—H17C	109.5
C13—C8—H8A	119.7	C19—C18—C15	126.7 (2)
O2—C9—C10	121.10 (16)	C19—C18—H18	119.3 (12)
O2—C9—C13	122.15 (16)	C15—C18—H18	113.4 (12)
C10—C9—C13	116.75 (15)	C18—C19—H19B	120.2 (13)
C11—C10—C1	117.58 (16)	C18—C19—H19A	122.6 (13)
C11—C10—C9	121.29 (16)	H19B—C19—H19A	116.8 (18)
C1—C10—C9	121.10 (15)	O6—C20—H20A	109.5
O1—C11—C4	116.11 (15)	O6—C20—H20B	109.5
O1—C11—C10	119.40 (15)	H20A—C20—H20B	109.5
C4—C11—C10	124.49 (16)	O6—C20—H20C	109.5
O1—C12—C5	115.05 (15)	H20A—C20—H20C	109.5
O1—C12—C13	123.19 (16)	H20B—C20—H20C	109.5
O3—C1—C2—C3	179.39 (16)	C3—C4—C11—C10	−5.7 (3)
C10—C1—C2—C3	−2.0 (3)	C15—C4—C11—C10	175.57 (17)
C14—O4—C3—C2	3.8 (3)	C1—C10—C11—O1	−176.47 (15)
C14—O4—C3—C4	−177.21 (16)	C9—C10—C11—O1	5.1 (3)
C1—C2—C3—O4	177.55 (16)	C1—C10—C11—C4	2.8 (3)
C1—C2—C3—C4	−1.4 (3)	C9—C10—C11—C4	−175.67 (17)
O4—C3—C4—C11	−174.00 (15)	C11—O1—C12—C5	−177.07 (15)
C2—C3—C4—C11	5.0 (3)	C11—O1—C12—C13	2.6 (2)
O4—C3—C4—C15	4.7 (3)	O5—C5—C12—O1	−2.9 (2)
C2—C3—C4—C15	−176.34 (17)	C6—C5—C12—O1	177.22 (15)
C20—O6—C6—C5	173.27 (16)	O5—C5—C12—C13	177.41 (16)
C20—O6—C6—C7	−7.4 (3)	C6—C5—C12—C13	−2.5 (3)
O5—C5—C6—O6	1.3 (3)	C7—C8—C13—C12	0.6 (3)
C12—C5—C6—O6	−178.80 (15)	C7—C8—C13—C9	−179.37 (17)
O5—C5—C6—C7	−178.04 (17)	O1—C12—C13—C8	−178.41 (16)
C12—C5—C6—C7	1.8 (3)	C5—C12—C13—C8	1.3 (3)
O6—C6—C7—C8	−179.31 (17)	O1—C12—C13—C9	1.6 (3)
C5—C6—C7—C8	0.0 (3)	C5—C12—C13—C9	−178.73 (16)
C6—C7—C8—C13	−1.2 (3)	O2—C9—C13—C8	−1.6 (3)
O3—C1—C10—C11	179.96 (16)	C10—C9—C13—C8	177.72 (16)
C2—C1—C10—C11	1.3 (3)	O2—C9—C13—C12	178.43 (17)
O3—C1—C10—C9	−1.6 (3)	C10—C9—C13—C12	−2.3 (2)
C2—C1—C10—C9	179.76 (17)	C11—C4—C15—C18	−160.22 (17)
O2—C9—C10—C11	178.32 (17)	C3—C4—C15—C18	21.2 (2)
C13—C9—C10—C11	−1.0 (3)	C11—C4—C15—C17	74.6 (2)
O2—C9—C10—C1	−0.1 (3)	C3—C4—C15—C17	−104.0 (2)
C13—C9—C10—C1	−179.36 (16)	C11—C4—C15—C16	−45.9 (2)
C12—O1—C11—C4	174.78 (15)	C3—C4—C15—C16	135.50 (18)
C12—O1—C11—C10	−5.9 (2)	C17—C15—C18—C19	−8.8 (3)
C3—C4—C11—O1	173.53 (15)	C16—C15—C18—C19	108.6 (2)
C15—C4—C11—O1	−5.2 (2)	C4—C15—C18—C19	−132.5 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1O3···O2	0.95 (3)	1.65 (3)	2.5573 (18)	160 (2)
O5—H1O5···O6	0.83 (2)	2.25 (2)	2.7019 (19)	115 (2)
O5—H1O5···O2i	0.83 (2)	1.98 (2)	2.7520 (18)	155 (2)
C8—H8A···O5ii	0.93	2.54	3.413 (2)	157

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H1O3⋯O2	0.95 (3)	1.65 (3)	2.5573 (18)	160 (2)
O5—H1O5⋯O6	0.83 (2)	2.25 (2)	2.7019 (19)	115 (2)
O5—H1O5⋯O2i	0.83 (2)	1.98 (2)	2.7520 (18)	155 (2)
C8—H8A⋯O5ii	0.93	2.54	3.413 (2)	157

Symmetry codes: (i) ; (ii) .