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One of the products obtained from the fruit of the indigenous Australian tree Melicope ellyrana has been confirmed as the flavonoid pachypodol (4,5′-di­hydroxy-3,3′,7-tri­methoxy­flavone), C18H16O7. This compound is similar to a number of the flavonones from the same species with the exception of the reduced side chain. The usual intramolecular hydrogen bonding between the hydroxy and the adjacent carbonyl or methoxy substituent groups is found, together with intermolecular hydrogen bonding between one of these hydroxy groups and a methoxy O atom [O...O 2.875 (4) Å], giving an infinite chain.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801015252/ci6060sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801015252/ci6060Isup2.hkl
Contains datablock I

CCDC reference: 175372

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.005 Å
  • R factor = 0.045
  • wR factor = 0.155
  • Data-to-parameter ratio = 12.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

The hexane extract of the fruit of the indigenous Australian tree Melicope ellyrana (formerly Euodia ellyrana F. Meull) (Hartley, 1981) has yielded, among other products the flavonoids, pachypodol [4',5-dihydroxy-3,3',7-trimethoxyflavone, (I)], ternatin [4',5-dihydroxy-3,3',7,8-tetramethoxyflavone, (II)], 4',5-dihydroxy-3,3',8-trimethoxy-7-(3-methylbut-2-enyloxy)flavone, (III), and 3',5-dihydroxy-3,4'-dimethoxy-7-(3-methylbut-2-enyloxy)flavone, (IV). Both (III) and (IV) have provided examples of dimorphism [for (III), triclinic and monoclinic (Smith et al., 2001a) and (IV), both triclinic representing distinctly different conformational variants (Smith et al., 2001b)]. With (III), this was the first report of its isolation from Melicope species, although it had previously been isolated from Boronia coerulescens (Ashan et al., 1994), while other prenylated flavones similar to (III) and (IV) have been reported, from M. triphylla (Higa et al., 1987) and M. micrococca (Nasim, 1999). Pachypodol has also been isolated from other plant types, e.g. Larrea cuneifolia (Valesi et al., 1972) and L. tridenta (Chirikdjian, 1974) as well as Pachypodanthium confine (Annonaceae) (Cave et al., 1973), but not previously from Melicope species.

The structure has revealed the basic flavone core similar to other reported flavonoids, e.g. 5-hydroxy-3,4',7-trimethoxyflavone (Gajhede et al., 1989), and to the other flavonone components from the same species. The greatest similarity is with the structure of the dimorphic pair (IV) but with the 3-methylbut-2-enyl side chain at C7 reduced. The usual intramolecular C—H···O (methoxy) and C—H···O (ether) interaction is significant in maintaining close to coplanarity in the two ring systems [C11—H3···O1 2.664 (4) Å and C15—H5···O3 2.898 (4) Å; torsion angle C2—C1—C10—C11 161.3 (4)°]. There is an intramolecular hydrogen-bonding interaction involving the hydroxyl group at C5 and the adjacent ketone oxygen (at C3) [O7—H15···O6 2.618 (4) Å] and between the hydroxyl group at C13 and the adjacent methoxy oxygen (at C14) [O4—H1···O5 2.688 (4) Å]. A single intermolecular hydrogen-bonding interaction is found between the H atom on this hydroxyl group and a methoxy O atom of an adjacent neighbour [O4—H1···O2 2.875 (4) Å; symmetry code: x, 1 + y, 1 + z]. This completes a three-centered hydrogen-bonding association about H1 and together with a weak C6—H2···O5 contact [3.494 (5) Å; symmetry code: x, -1 + y, -1 + z] gives an infinite chain parallel to the `b' cell direction (Fig. 2). Unusual weak centrosymmetric cyclic hydrogen-bonding intermolecular associations between the oxygen and a methyl H atom of the methoxy substituent group at C2 link the primary chains peripherally [C17—H9···O3 3.433 (5) Å; symmetry code: -x, 2 - y, 1 - z].

Experimental top

The title compound was obtained as one of the 23 fractions from the n-hexane extract of the fresh fruit of Melicope ellyrana (Smith et al., 2001a).

Refinement top

The H atoms of both hydroxyl groups were located from a difference map and their positional parameters only were refined while the remainder were included at calculated positions and allowed to ride with the attached atom.

Computing details top

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999a); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1999b); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON for Windows (Spek, 1999); software used to prepare material for publication: TEXSAN for Windows.

Figures top
[Figure 1]
[Figure 2]
Fig. 1. The molecular configuration and atom-naming scheme for (I). Atoms are shown as 40% probability ellipsoids.
4,5'-dihydroxy-3,3',7-trimethoxyflavone top
Crystal data top
C18H16O7Z = 2
Mr = 344.31F(000) = 360
Triclinic, P1Dx = 1.442 Mg m3
a = 9.399 (6) ÅMo Kα radiation, λ = 0.71069 Å
b = 11.836 (9) ÅCell parameters from 25 reflections
c = 8.041 (3) Åθ = 11.0–19.5°
α = 97.64 (5)°µ = 0.11 mm1
β = 111.08 (3)°T = 293 K
γ = 71.83 (7)°Prismatic, yellow
V = 792.8 (8) Å30.60 × 0.20 × 0.20 mm
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.073
Radiation source: Rigaku rotating anodeθmax = 25.1°, θmin = 2.6°
Graphite monochromatorh = 011
ω–2θ scansk = 1314
2983 measured reflectionsl = 98
2798 independent reflections3 standard reflections every 150 reflections
1383 reflections with I > 2σ(I) intensity decay: 0.8%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.155H atoms treated by a mixture of independent and constrained refinement
S = 1.00 w = 1/[σ2(Fo2) + (0.0773P)2 + 0.0882P]
where P = (Fo2 + 2Fc2)/3
2798 reflections(Δ/σ)max < 0.001
233 parametersΔρmax = 0.20 e Å3
0 restraintsΔρmin = 0.29 e Å3
Crystal data top
C18H16O7γ = 71.83 (7)°
Mr = 344.31V = 792.8 (8) Å3
Triclinic, P1Z = 2
a = 9.399 (6) ÅMo Kα radiation
b = 11.836 (9) ŵ = 0.11 mm1
c = 8.041 (3) ÅT = 293 K
α = 97.64 (5)°0.60 × 0.20 × 0.20 mm
β = 111.08 (3)°
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.073
2983 measured reflections3 standard reflections every 150 reflections
2798 independent reflections intensity decay: 0.8%
1383 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.155H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.20 e Å3
2798 reflectionsΔρmin = 0.29 e Å3
233 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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
xyzUiso*/Ueq
O10.5549 (2)0.67398 (16)0.4730 (3)0.0416 (6)
O20.7168 (3)0.30782 (19)0.1726 (3)0.0572 (7)
O30.1697 (2)0.87229 (17)0.4575 (3)0.0447 (6)
O40.7394 (3)1.0726 (2)1.0165 (3)0.0602 (7)
O50.4334 (2)1.16198 (17)0.8146 (3)0.0500 (6)
O60.0885 (3)0.6939 (2)0.2185 (3)0.0642 (7)
O70.1743 (3)0.4917 (2)0.0539 (3)0.0666 (8)
C10.4398 (3)0.7707 (2)0.5028 (4)0.0382 (7)
C20.2840 (3)0.7803 (2)0.4158 (4)0.0384 (7)
C30.2329 (4)0.6885 (3)0.2918 (4)0.0426 (8)
C40.3578 (3)0.5905 (2)0.2616 (4)0.0390 (7)
C50.3259 (4)0.4943 (3)0.1424 (4)0.0460 (8)
C60.4496 (4)0.4029 (3)0.1164 (4)0.0484 (8)
C70.6058 (4)0.4030 (2)0.2094 (4)0.0433 (8)
C80.6428 (4)0.4942 (3)0.3299 (4)0.0426 (8)
C90.5163 (3)0.5859 (2)0.3514 (4)0.0372 (7)
C100.5142 (3)0.8505 (2)0.6393 (4)0.0365 (7)
C110.6709 (4)0.8100 (3)0.7484 (4)0.0432 (8)
C120.7448 (4)0.8843 (3)0.8746 (4)0.0457 (8)
C130.6618 (3)1.0015 (3)0.8936 (4)0.0413 (8)
C140.5040 (3)1.0443 (2)0.7858 (4)0.0382 (7)
C150.4307 (3)0.9697 (3)0.6611 (4)0.0415 (8)
C160.2678 (4)1.2085 (3)0.7215 (5)0.0558 (9)
C170.0697 (4)0.9524 (3)0.3142 (5)0.0561 (9)
C180.8813 (5)0.2993 (3)0.2640 (6)0.0685 (11)
H10.672 (4)1.135 (3)1.015 (5)0.058*
H20.42820.33980.03420.057*
H30.72870.72940.73670.052*
H40.85280.85450.94860.054*
H50.32210.99940.58970.050*
H60.22891.28460.77010.066*
H90.00471.01380.35340.067*
H100.13360.98580.27850.067*
H110.01490.90990.21620.067*
H120.90420.29670.38820.081*
H130.94460.22880.22460.081*
H140.90370.36650.23770.081*
H150.117 (4)0.559 (3)0.095 (5)0.061*
H160.74980.49450.39400.051*
H70.25081.21600.59860.066*
H80.21251.15640.73150.066*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0384 (12)0.0310 (11)0.0449 (12)0.0064 (9)0.0090 (10)0.0107 (9)
O20.0589 (15)0.0388 (13)0.0642 (16)0.0031 (11)0.0241 (13)0.0135 (11)
O30.0400 (12)0.0361 (12)0.0487 (13)0.0034 (10)0.0129 (10)0.0058 (10)
O40.0475 (14)0.0438 (14)0.0659 (16)0.0088 (11)0.0042 (12)0.0234 (13)
O50.0404 (13)0.0330 (12)0.0616 (15)0.0051 (10)0.0095 (11)0.0132 (10)
O60.0426 (14)0.0515 (14)0.0832 (18)0.0138 (11)0.0109 (13)0.0205 (13)
O70.0529 (16)0.0486 (15)0.0804 (19)0.0178 (12)0.0081 (14)0.0246 (13)
C10.0423 (19)0.0264 (15)0.0414 (18)0.0059 (14)0.0138 (15)0.0037 (13)
C20.0386 (18)0.0284 (16)0.0444 (19)0.0049 (13)0.0150 (15)0.0033 (13)
C30.0376 (19)0.0375 (17)0.048 (2)0.0121 (14)0.0094 (15)0.0032 (14)
C40.0427 (18)0.0311 (16)0.0383 (17)0.0100 (14)0.0096 (14)0.0025 (13)
C50.049 (2)0.0374 (18)0.0465 (19)0.0162 (15)0.0098 (15)0.0088 (15)
C60.062 (2)0.0343 (17)0.0452 (19)0.0148 (16)0.0167 (17)0.0098 (14)
C70.052 (2)0.0294 (16)0.0467 (19)0.0064 (14)0.0201 (16)0.0029 (14)
C80.0458 (19)0.0326 (16)0.0445 (19)0.0076 (14)0.0147 (15)0.0052 (14)
C90.0436 (18)0.0300 (16)0.0359 (17)0.0113 (14)0.0119 (14)0.0042 (13)
C100.0379 (17)0.0329 (16)0.0358 (16)0.0094 (13)0.0109 (14)0.0023 (13)
C110.0444 (19)0.0305 (16)0.0480 (19)0.0056 (14)0.0145 (15)0.0063 (14)
C120.0367 (17)0.0429 (18)0.0446 (19)0.0060 (14)0.0058 (14)0.0065 (15)
C130.0404 (18)0.0378 (18)0.0408 (18)0.0123 (14)0.0104 (15)0.0090 (14)
C140.0434 (18)0.0259 (15)0.0431 (18)0.0069 (13)0.0179 (15)0.0087 (13)
C150.0344 (17)0.0347 (17)0.0461 (19)0.0055 (14)0.0081 (14)0.0036 (14)
C160.043 (2)0.0390 (19)0.071 (2)0.0038 (15)0.0109 (17)0.0051 (17)
C170.051 (2)0.0409 (19)0.062 (2)0.0023 (16)0.0109 (17)0.0015 (17)
C180.063 (3)0.050 (2)0.089 (3)0.0011 (18)0.037 (2)0.0074 (19)
Geometric parameters (Å, º) top
O1—C91.372 (3)C7—C81.393 (4)
O1—C11.371 (3)C8—C91.384 (4)
O2—C71.358 (4)C8—H160.95
O2—C181.431 (4)C10—C111.382 (4)
O3—C21.373 (3)C10—C151.408 (4)
O3—C171.437 (4)C11—C121.386 (4)
O4—C131.364 (4)C11—H30.95
O4—H10.81 (3)C12—C131.381 (4)
O5—C141.372 (3)C12—H40.95
O5—C161.422 (4)C13—C141.390 (4)
O6—C31.255 (4)C14—C151.380 (4)
O7—C51.353 (4)C15—H50.95
O7—H150.91 (3)C16—H60.95
C1—C21.352 (4)C16—H70.96
C1—C101.472 (4)C16—H80.95
C2—C31.448 (4)C17—H90.95
C3—C41.436 (4)C17—H100.95
C4—C91.389 (4)C17—H110.95
C4—C51.422 (4)C18—H120.95
C5—C61.377 (5)C18—H130.95
C6—C71.388 (4)C18—H140.95
C6—H20.95
C9—O1—C1121.4 (2)C15—C10—C1121.7 (3)
C7—O2—C18118.5 (3)C10—C11—C12121.4 (3)
C2—O3—C17114.3 (2)C10—C11—H3119
C13—O4—H1105 (3)C12—C11—H3120
C14—O5—C16117.8 (2)C13—C12—C11120.1 (3)
C5—O7—H15102 (2)C13—C12—H4120
C2—C1—O1120.5 (2)C11—C12—H4120
C2—C1—C10129.5 (3)O4—C13—C12118.5 (3)
O1—C1—C10109.9 (2)O4—C13—C14121.8 (3)
C1—C2—O3120.0 (3)C12—C13—C14119.7 (3)
C1—C2—C3121.6 (3)O5—C14—C15125.1 (3)
O3—C2—C3118.0 (3)O5—C14—C13114.9 (3)
O6—C3—C4122.5 (3)C15—C14—C13120.0 (3)
O6—C3—C2121.7 (3)C14—C15—C10120.9 (3)
C4—C3—C2115.8 (3)C14—C15—H5119
C9—C4—C5117.3 (3)C10—C15—H5120
C9—C4—C3120.5 (3)O5—C16—H6110
C5—C4—C3122.2 (3)O5—C16—H7109
O7—C5—C6119.5 (3)H6—C16—H7109
O7—C5—C4120.4 (3)O5—C16—H8110
C6—C5—C4120.1 (3)H6—C16—H8110
C5—C6—C7120.1 (3)H7—C16—H8109
C5—C6—H2120O3—C17—H9109
C7—C6—H2120O3—C17—H10109
O2—C7—C6114.5 (3)H9—C17—H10110
O2—C7—C8123.7 (3)O3—C17—H11109
C6—C7—C8121.8 (3)H9—C17—H11110
C9—C8—C7116.8 (3)H10—C17—H11110
C9—C8—H16121O2—C18—H12110
C7—C8—H16122O2—C18—H13109
O1—C9—C8116.1 (3)H12—C18—H13110
O1—C9—C4120.1 (3)O2—C18—H14109
C8—C9—C4123.8 (3)H12—C18—H14110
C11—C10—C15117.9 (3)H13—C18—H14109
C11—C10—C1120.3 (3)
C9—O1—C1—C21.7 (4)C1—O1—C9—C8178.5 (3)
C9—O1—C1—C10179.8 (2)C1—O1—C9—C43.1 (4)
O1—C1—C2—O3174.5 (3)C7—C8—C9—O1178.9 (3)
C10—C1—C2—O33.2 (5)C7—C8—C9—C40.5 (5)
O1—C1—C2—C31.4 (5)C5—C4—C9—O1177.7 (3)
C10—C1—C2—C3176.4 (3)C3—C4—C9—O11.4 (4)
C17—O3—C2—C1116.6 (3)C5—C4—C9—C80.6 (5)
C17—O3—C2—C370.0 (4)C3—C4—C9—C8179.7 (3)
C1—C2—C3—O6175.9 (3)C2—C1—C10—C11161.4 (3)
O3—C2—C3—O62.6 (5)O1—C1—C10—C1116.6 (4)
C1—C2—C3—C42.8 (4)C2—C1—C10—C1519.9 (5)
O3—C2—C3—C4176.1 (3)O1—C1—C10—C15162.2 (3)
O6—C3—C4—C9177.3 (3)C15—C10—C11—C120.6 (5)
C2—C3—C4—C91.5 (4)C1—C10—C11—C12178.2 (3)
O6—C3—C4—C51.8 (5)C10—C11—C12—C130.0 (5)
C2—C3—C4—C5179.5 (3)C11—C12—C13—O4178.6 (3)
C9—C4—C5—O7178.4 (3)C11—C12—C13—C140.1 (5)
C3—C4—C5—O70.7 (5)C16—O5—C14—C156.4 (4)
C9—C4—C5—C61.6 (5)C16—O5—C14—C13173.9 (3)
C3—C4—C5—C6179.3 (3)O4—C13—C14—O50.7 (4)
O7—C5—C6—C7178.5 (3)C12—C13—C14—O5179.5 (3)
C4—C5—C6—C71.4 (5)O4—C13—C14—C15179.0 (3)
C18—O2—C7—C6179.1 (3)C12—C13—C14—C150.3 (5)
C18—O2—C7—C80.9 (5)O5—C14—C15—C10178.9 (3)
C5—C6—C7—O2179.7 (3)C13—C14—C15—C100.9 (5)
C5—C6—C7—C80.3 (5)C11—C10—C15—C141.0 (5)
O2—C7—C8—C9179.3 (3)C1—C10—C15—C14177.8 (3)
C6—C7—C8—C90.7 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H1···O2i0.81 (4)2.33 (4)2.875 (4)125 (3)
O4—H1···O50.81 (4)2.20 (4)2.688 (4)120 (3)
O7—H15···O60.91 (4)1.76 (3)2.618 (4)156 (4)
C6—H2···O5ii0.952.563.494 (5)167
C11—H3···O10.952.322.664 (4)100
C15—H5···O30.952.302.898 (4)121
C17—H9···O3iii0.952.533.433 (5)160
C17—H11···O60.952.433.020 (5)120
Symmetry codes: (i) x, y+1, z+1; (ii) x, y1, z1; (iii) x, y+2, z+1.

Experimental details

Crystal data
Chemical formulaC18H16O7
Mr344.31
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)9.399 (6), 11.836 (9), 8.041 (3)
α, β, γ (°)97.64 (5), 111.08 (3), 71.83 (7)
V3)792.8 (8)
Z2
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.60 × 0.20 × 0.20
Data collection
DiffractometerRigaku AFC-7R
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2983, 2798, 1383
Rint0.073
(sin θ/λ)max1)0.596
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.155, 1.00
No. of reflections2798
No. of parameters233
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.20, 0.29

Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999a), MSC/AFC Diffractometer Control Software, TEXSAN for Windows (Molecular Structure Corporation, 1999b), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON for Windows (Spek, 1999), TEXSAN for Windows.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H1···O2i0.81 (4)2.33 (4)2.875 (4)125 (3)
O4—H1···O50.81 (4)2.20 (4)2.688 (4)120 (3)
O7—H15···O60.91 (4)1.76 (3)2.618 (4)156 (4)
C6—H2···O5ii0.952.563.494 (5)167
C11—H3···O10.952.322.664 (4)100
C15—H5···O30.952.302.898 (4)121
C17—H9···O3iii0.952.533.433 (5)160
C17—H11···O60.952.433.020 (5)120
Symmetry codes: (i) x, y+1, z+1; (ii) x, y1, z1; (iii) x, y+2, z+1.
 

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