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The crystal structure of the title compound, 5,4′-di­hydroxy-6,7-di­methoxy­flavone, C17H14O6, isolated from Salvia nubicola, is composed of chains that are stabilized by conventional (O—H...O type) intramolecular and intermolecular hydrogen bonds with O...O being 2.5780 (16) and 2.7459 (15) Å, respectively. The benzo­pyran ring is essentially planar with hydroxyl and carbonyl O atoms lying close to its mean plane, the methoxyl groups inclined at 65.90 (11) and 8.39 (10)°, and the phenyl ring oriented at 23.30 (6)° from the benzo­pyran ring. The mean bond distances are: O—Csp3 1.4372 (18), O—Csp2 1.365 (12), Csp2—Csp2 1.448 (17), C—Caromatic 1.393 (10) and C=O 1.2559 (19) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802002660/cv6089sup1.cif
Contains datablocks Global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536802002660/cv6089Isup2.hkl
Contains datablock I

CCDC reference: 182621

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.048
  • wR factor = 0.157
  • Data-to-parameter ratio = 18.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Amber Alert Alert Level B:
PLAT_030 Alert B Refined Extinction parameter within range .... 1.00 Sigma
Yellow Alert Alert Level C:
ABSMU_01 Alert C The ratio of given/expected absorption coefficient lies outside the range 0.99 <> 1.01 Calculated value of mu = 0.111 Value of mu given = 0.110 REFLT_03 From the CIF: _diffrn_reflns_theta_max 30.00 From the CIF: _reflns_number_total 3958 TEST2: Reflns within _diffrn_reflns_theta_max Count of symmetry unique reflns 4185 Completeness (_total/calc) 94.58% Alert C: < 95% complete
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

Salvia is the largest genus of the plant family Lamiaceae (previously known as Labiateae) comprising aromatic and ornamental herbs and shrubs distributed in the temperate and tropical regions. Species of Salvia are known to contain terpenes and steroids (Pereda-Miranda et al., 1986). We have isolated 5,4'-dihydroxy-6,7-dimethoxyflavone (cirsimaritin), (I), from Salvia nubicola Wall. ex Sweet; it had been previously isolated from Centaurea scoparia (Youssef & Frahm, 1995). The crystal structure of a very closely related flavone, eupatorin, has been reported from our laboratory (Parvez et al., 2001). The inhibitory effects of (I) on both bovine-LAR and rabbit platellet aggregation have been reported (Okada et al., 1995). The crystal structure of (I) has been determined by X-ray crystallographic method which is reported in this paper.

The structure of (I) is presented in Fig. 1. The benzopyran ring is planar within 0.0314 (11) Å. The mean plane of phenyl ring C1'-C6' is inclined at 23.30 (6)° to the mean plane of the benzopyran ring. The carbonyl O2 and hydroxyl O3 lie slightly above [0.044 (2) Å] and below [0.066 (2) Å] the plane of the benzopyran ring. The methoxy groups O4/C11 and O5/C12 are oriented at 65.90 (11) and 8.39 (10)°, respectively, from the benzopyran ring. The molecular dimensions in (I) lie within expected values (Orpen et al., 1994) for the corresponding bond distances and angles and agree well with those reported for a dozen or so similar compounds contained in the October 2001 updates of the Cambridge Structural Database (Allen & Kennard, 1993). The mean bond distances are: O—Csp3 1.4372 (18), O—Csp2 1.365 (12), Csp2—Csp2 1.448 (17), C—Caromatic 1.393 (10) and CO 1.2559 (19) Å.

The structure is stabilized by strong intramolecular and intermolecular hydrogen bonds. The hydroxyl H atom is intramolecularly bonded with the carbonyl O atom [H3···O2 1.85, O3···O2 2.5780 (16) Å and O3—H3···O2 148°]. The intermolecular hydrogen bond between the 6-methoxy O4 and the 4'-hydroxyl H atoms [H4'···O4 1.95, O4'···O4 2.7459 (15) Å and O4'—H4'···O4 164°] results in a chain structure along the c axis; details of the hydrogen-bonding geometry have been provided in Table 2 and are presented in Fig. 2.

Experimental top

The plant material (all parts, 13 kg) was collected from Quetta, Pakistan, in July 1999, dried under shade for a period of two weeks, and soaked in hexane (12 l × 2) and methanol (12 l × 2) for 10 d in each solvent. Solvents were evaporated through vacuum distillation. The crude methanolic extract (217 g) was partitioned between water and ethyl acetate. The ethyl acetate layer was condensed (167 g) and subjected to column chromatography using hexane, hexane–ethyl acetate, ethyl acetate and ethyl acetate–methanol as mobile phases. Elution with 20% ethyl acetate in hexane afforded yellow crystals (11.6 mg) suitable for XRD analysis.

Refinement top

The space group was determined uniquely from the systematic absences. The H atoms were located from difference Fourier synthesis and were included in the refinement at geometrically idealized positions, with C—H 0.93–0.96 Å and O—H 0.82 Å, utilizing riding models.

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: HKL DENZO (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SAPI91 (Fan, 1991); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: TEXSAN (Molecular Structure Corporation, 1994); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. ORTEPII (Johnson, 1976) drawing of (I) with displacement ellipsoids plotted at 50% probability level.
[Figure 2] Fig. 2. Hydrogen-bonding pattern in (I) showing a hydrogen-bonded polymeric chain along the c axis.
(5,4'-Dihydroxy-6,7-dimethoxyflavone) top
Crystal data top
C17H14O6Dx = 1.455 Mg m3
Mr = 314.28Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PbcaCell parameters from 3674 reflections
a = 8.3669 (2) Åθ = 1.0–30.0°
b = 13.5769 (4) ŵ = 0.11 mm1
c = 25.2554 (9) ÅT = 293 K
V = 2868.93 (15) Å3Prismatic, yellow
Z = 80.25 × 0.25 × 0.13 mm
F(000) = 1312
Data collection top
Nonius KappaCCD
diffractometer
3958 independent reflections
Radiation source: fine-focus sealed tube2594 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
ω–2ϕ scansθmax = 30.0°, θmin = 3.2°
Absorption correction: multi-scan
(SORTAV: Blessing, 1995, 1997)
h = 1111
Tmin = 0.973, Tmax = 0.986k = 1818
6714 measured reflectionsl = 3535
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.048H-atom parameters constrained
wR(F2) = 0.157 w = 1/[σ2(Fo2) + (0.092P)2 + 0.124P]
where P = (Fo2 + 2Fc2)/3
S = 0.98(Δ/σ)max < 0.001
3958 reflectionsΔρmax = 0.22 e Å3
211 parametersΔρmin = 0.19 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.004 (4)
Crystal data top
C17H14O6V = 2868.93 (15) Å3
Mr = 314.28Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 8.3669 (2) ŵ = 0.11 mm1
b = 13.5769 (4) ÅT = 293 K
c = 25.2554 (9) Å0.25 × 0.25 × 0.13 mm
Data collection top
Nonius KappaCCD
diffractometer
3958 independent reflections
Absorption correction: multi-scan
(SORTAV: Blessing, 1995, 1997)
2594 reflections with I > 2σ(I)
Tmin = 0.973, Tmax = 0.986Rint = 0.036
6714 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.157H-atom parameters constrained
S = 0.98Δρmax = 0.22 e Å3
3958 reflectionsΔρmin = 0.19 e Å3
211 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.80664 (14)0.24686 (7)0.80247 (4)0.0381 (3)
O21.02299 (16)0.51658 (8)0.80368 (5)0.0536 (4)
O30.99288 (17)0.52501 (8)0.70219 (5)0.0516 (3)
H31.01790.54320.73200.077*
O40.88775 (12)0.43326 (7)0.61005 (4)0.0371 (3)
O50.77847 (13)0.25240 (7)0.61361 (4)0.0387 (3)
C20.84898 (17)0.29054 (11)0.84907 (6)0.0349 (3)
C30.9234 (2)0.37910 (11)0.85047 (6)0.0400 (4)
H3A0.95340.40520.88300.048*
C40.95727 (19)0.43342 (11)0.80347 (6)0.0382 (4)
C50.92861 (18)0.43392 (10)0.70475 (6)0.0356 (4)
C60.88195 (17)0.38706 (10)0.65878 (6)0.0336 (3)
C70.81601 (16)0.29160 (10)0.66133 (6)0.0320 (3)
C80.79119 (18)0.24486 (11)0.70964 (6)0.0339 (3)
H80.74580.18240.71130.041*
C90.83633 (18)0.29435 (10)0.75520 (6)0.0331 (3)
C100.90838 (18)0.38715 (10)0.75431 (6)0.0342 (3)
C111.04456 (19)0.45254 (14)0.58946 (8)0.0514 (5)
H11A1.03560.48490.55580.077*
H11B1.10100.39150.58520.077*
H11C1.10190.49410.61370.077*
C120.72652 (19)0.15138 (11)0.61253 (6)0.0402 (4)
H12A0.70380.13240.57670.060*
H12B0.63180.14440.63360.060*
H12C0.80930.11000.62650.060*
O4'0.66934 (13)0.07247 (9)1.02896 (4)0.0458 (3)
H4'0.73160.08221.05350.069*
C1'0.80245 (17)0.23266 (11)0.89568 (6)0.0342 (3)
C2'0.87905 (19)0.24867 (12)0.94417 (6)0.0406 (4)
H2'0.96050.29510.94630.049*
C3'0.83574 (18)0.19664 (12)0.98898 (6)0.0414 (4)
H3'0.88810.20811.02090.050*
C4'0.71426 (17)0.12738 (10)0.98637 (6)0.0343 (3)
C5'0.63504 (17)0.11167 (12)0.93868 (6)0.0379 (4)
H5'0.55180.06640.93700.045*
C6'0.67942 (17)0.16312 (11)0.89360 (6)0.0370 (4)
H6'0.62700.15130.86180.044*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0562 (6)0.0354 (6)0.0227 (5)0.0062 (5)0.0028 (4)0.0002 (4)
O20.0764 (9)0.0399 (7)0.0446 (7)0.0172 (6)0.0116 (6)0.0043 (5)
O30.0762 (8)0.0345 (6)0.0442 (7)0.0169 (6)0.0165 (6)0.0049 (5)
O40.0415 (6)0.0382 (6)0.0315 (6)0.0045 (4)0.0033 (4)0.0112 (5)
O50.0577 (6)0.0348 (6)0.0237 (5)0.0076 (5)0.0035 (5)0.0001 (4)
C20.0392 (7)0.0396 (8)0.0261 (7)0.0035 (6)0.0032 (6)0.0034 (6)
C30.0519 (9)0.0403 (9)0.0277 (8)0.0021 (7)0.0043 (7)0.0060 (6)
C40.0450 (8)0.0350 (8)0.0347 (8)0.0005 (6)0.0062 (6)0.0045 (6)
C50.0436 (8)0.0281 (7)0.0350 (8)0.0019 (6)0.0064 (6)0.0040 (6)
C60.0392 (7)0.0318 (7)0.0298 (8)0.0009 (6)0.0046 (6)0.0061 (6)
C70.0367 (7)0.0324 (7)0.0269 (7)0.0001 (6)0.0029 (6)0.0001 (6)
C80.0462 (8)0.0286 (7)0.0269 (7)0.0048 (6)0.0030 (6)0.0007 (6)
C90.0409 (8)0.0330 (7)0.0253 (7)0.0008 (6)0.0020 (6)0.0021 (6)
C100.0427 (8)0.0297 (7)0.0301 (8)0.0005 (6)0.0063 (6)0.0001 (6)
C110.0457 (9)0.0589 (11)0.0495 (11)0.0028 (7)0.0063 (8)0.0118 (9)
C120.0522 (9)0.0361 (8)0.0323 (8)0.0060 (6)0.0048 (7)0.0022 (6)
O4'0.0489 (6)0.0585 (7)0.0301 (6)0.0075 (5)0.0027 (5)0.0058 (5)
C1'0.0391 (7)0.0384 (8)0.0250 (7)0.0049 (6)0.0006 (6)0.0023 (6)
C2'0.0454 (8)0.0497 (9)0.0267 (8)0.0089 (7)0.0035 (6)0.0024 (7)
C3'0.0467 (8)0.0517 (9)0.0258 (8)0.0036 (7)0.0041 (6)0.0036 (7)
C4'0.0370 (7)0.0392 (8)0.0267 (7)0.0047 (6)0.0020 (6)0.0012 (6)
C5'0.0384 (8)0.0415 (8)0.0338 (8)0.0014 (6)0.0032 (6)0.0018 (7)
C6'0.0406 (8)0.0417 (8)0.0288 (8)0.0012 (6)0.0064 (6)0.0036 (6)
Geometric parameters (Å, º) top
O1—C21.3645 (16)C9—C101.397 (2)
O1—C91.3794 (16)C11—H11A0.9600
O2—C41.2559 (19)C11—H11B0.9600
O3—C51.3502 (17)C11—H11C0.9600
O3—H30.8200C12—H12A0.9600
O4—C61.3821 (17)C12—H12B0.9600
O4—C111.4353 (19)C12—H12C0.9600
O5—C71.3544 (16)O4'—C4'1.3617 (17)
O5—C121.4390 (17)O4'—H4'0.8200
C2—C31.355 (2)C1'—C6'1.398 (2)
C2—C1'1.468 (2)C1'—C2'1.399 (2)
C3—C41.426 (2)C2'—C3'1.383 (2)
C3—H3A0.9300C2'—H2'0.9300
C4—C101.450 (2)C3'—C4'1.386 (2)
C5—C61.380 (2)C3'—H3'0.9300
C5—C101.414 (2)C4'—C5'1.391 (2)
C6—C71.410 (2)C5'—C6'1.386 (2)
C7—C81.3908 (19)C5'—H5'0.9300
C8—C91.3850 (19)C6'—H6'0.9300
C8—H80.9300
C2—O1—C9119.77 (11)O4—C11—H11A109.5
C5—O3—H3109.5O4—C11—H11B109.5
C6—O4—C11115.94 (12)H11A—C11—H11B109.5
C7—O5—C12117.49 (12)O4—C11—H11C109.5
C3—C2—O1121.85 (13)H11A—C11—H11C109.5
C3—C2—C1'125.18 (14)H11B—C11—H11C109.5
O1—C2—C1'112.96 (13)O5—C12—H12A109.5
C2—C3—C4121.91 (14)O5—C12—H12B109.5
C2—C3—H3A119.0H12A—C12—H12B109.5
C4—C3—H3A119.0O5—C12—H12C109.5
O2—C4—C3123.25 (14)H12A—C12—H12C109.5
O2—C4—C10121.10 (14)H12B—C12—H12C109.5
C3—C4—C10115.64 (13)C4'—O4'—H4'109.5
O3—C5—C6119.64 (13)C6'—C1'—C2'118.38 (14)
O3—C5—C10120.09 (13)C6'—C1'—C2121.78 (14)
C6—C5—C10120.26 (13)C2'—C1'—C2119.82 (14)
C5—C6—O4122.00 (12)C3'—C2'—C1'121.13 (14)
C5—C6—C7119.72 (13)C3'—C2'—H2'119.4
O4—C6—C7118.14 (12)C1'—C2'—H2'119.4
O5—C7—C8124.52 (13)C2'—C3'—C4'119.98 (14)
O5—C7—C6114.28 (12)C2'—C3'—H3'120.0
C8—C7—C6121.19 (13)C4'—C3'—H3'120.0
C9—C8—C7117.83 (13)O4'—C4'—C3'122.42 (14)
C9—C8—H8121.1O4'—C4'—C5'117.93 (13)
C7—C8—H8121.1C3'—C4'—C5'119.65 (14)
O1—C9—C8116.31 (12)C6'—C5'—C4'120.40 (14)
O1—C9—C10120.88 (12)C6'—C5'—H5'119.8
C8—C9—C10122.81 (13)C4'—C5'—H5'119.8
C9—C10—C5118.10 (13)C5'—C6'—C1'120.44 (14)
C9—C10—C4119.91 (13)C5'—C6'—H6'119.8
C5—C10—C4121.99 (13)C1'—C6'—H6'119.8
C9—O1—C2—C31.6 (2)C8—C9—C10—C53.1 (2)
C9—O1—C2—C1'177.30 (11)O1—C9—C10—C41.8 (2)
O1—C2—C3—C42.1 (2)C8—C9—C10—C4178.03 (14)
C1'—C2—C3—C4176.59 (14)O3—C5—C10—C9177.83 (14)
C2—C3—C4—O2178.40 (16)C6—C5—C10—C91.8 (2)
C2—C3—C4—C100.7 (2)O3—C5—C10—C41.0 (2)
O3—C5—C6—O44.9 (2)C6—C5—C10—C4179.37 (13)
C10—C5—C6—O4174.69 (13)O2—C4—C10—C9179.64 (15)
O3—C5—C6—C7179.48 (14)C3—C4—C10—C91.3 (2)
C10—C5—C6—C70.9 (2)O2—C4—C10—C51.5 (2)
C11—O4—C6—C569.29 (19)C3—C4—C10—C5177.57 (13)
C11—O4—C6—C7115.04 (15)C3—C2—C1'—C6'156.21 (16)
C12—O5—C7—C87.4 (2)O1—C2—C1'—C6'22.6 (2)
C12—O5—C7—C6173.57 (13)C3—C2—C1'—C2'21.9 (2)
C5—C6—C7—O5178.47 (13)O1—C2—C1'—C2'159.30 (13)
O4—C6—C7—O55.75 (19)C6'—C1'—C2'—C3'0.6 (2)
C5—C6—C7—C82.5 (2)C2—C1'—C2'—C3'178.76 (14)
O4—C6—C7—C8173.27 (13)C1'—C2'—C3'—C4'0.2 (2)
O5—C7—C8—C9179.81 (13)C2'—C3'—C4'—O4'178.44 (14)
C6—C7—C8—C91.3 (2)C2'—C3'—C4'—C5'0.9 (2)
C2—O1—C9—C8179.43 (12)O4'—C4'—C5'—C6'177.83 (13)
C2—O1—C9—C100.5 (2)C3'—C4'—C5'—C6'1.5 (2)
C7—C8—C9—O1178.54 (12)C4'—C5'—C6'—C1'1.1 (2)
C7—C8—C9—C101.6 (2)C2'—C1'—C6'—C5'0.1 (2)
O1—C9—C10—C5177.04 (13)C2—C1'—C6'—C5'178.08 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H4···O4i0.821.952.7459 (15)164
O3—H3···O20.821.852.5780 (16)148
Symmetry code: (i) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC17H14O6
Mr314.28
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)293
a, b, c (Å)8.3669 (2), 13.5769 (4), 25.2554 (9)
V3)2868.93 (15)
Z8
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.25 × 0.25 × 0.13
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(SORTAV: Blessing, 1995, 1997)
Tmin, Tmax0.973, 0.986
No. of measured, independent and
observed [I > 2σ(I)] reflections
6714, 3958, 2594
Rint0.036
(sin θ/λ)max1)0.703
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.157, 0.98
No. of reflections3958
No. of parameters211
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.22, 0.19

Computer programs: COLLECT (Hooft, 1998), HKL DENZO (Otwinowski & Minor, 1997), SCALEPACK (Otwinowski & Minor, 1997), SAPI91 (Fan, 1991), SHELXL97 (Sheldrick, 1997), TEXSAN (Molecular Structure Corporation, 1994).

Selected geometric parameters (Å, º) top
O1—C21.3645 (16)O4—C111.4353 (19)
O1—C91.3794 (16)O5—C71.3544 (16)
O2—C41.2559 (19)O5—C121.4390 (17)
O3—C51.3502 (17)O4'—C4'1.3617 (17)
O4—C61.3821 (17)
C2—O1—C9119.77 (11)C7—O5—C12117.49 (12)
C6—O4—C11115.94 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4'—H4'···O4i0.821.952.7459 (15)164
O3—H3···O20.821.852.5780 (16)148
Symmetry code: (i) x, y+1/2, z+1/2.
 

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