PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2008 May 1; 64(Pt 5): o893.
Published online 2008 April 23. doi:  10.1107/S1600536808010672
PMCID: PMC2961316

7-Eth­oxy-4′-methoxy­isoflavone (monoethyl­formononetin)

Abstract

The title compound, C18H16O4, is composed of a benzopyran­one core with a 4-methoxy­phenyl subsituent in the 3-position and an additional eth­oxy group in the 7-position. The benzopyran­one ring is not coplanar with the benzene ring, the dihedral angle between them being 41.76 (7)°. The meth­oxy and eth­oxy substituents are nearly coplanar with the ring systems to which they are attached. Individual mol­ecules are linked by two kinds of inter­molecular hydrogen bonds into chains containing classical R 2 2(8) rings. The chains are further assembled by aromatic F-tape and T-tape stacking inter­actions and additional inter­molecular hydrogen bonding to give a two-dimensional network.

Related literature

For related literature, see: Cassidy et al. (1994 [triangle]); Janiak (2000 [triangle]); Jha et al. (1985 [triangle]); Potter (1995 [triangle]); Sirtori et al. (1995 [triangle]); Zhang et al. (2005 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-0o893-scheme1.jpg

Experimental

Crystal data

  • C18H16O4
  • M r = 296.31
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-0o893-efi1.jpg
  • a = 6.234 (3) Å
  • b = 10.257 (5) Å
  • c = 12.159 (6) Å
  • α = 80.837 (7)°
  • β = 87.728 (8)°
  • γ = 73.653 (7)°
  • V = 736.5 (6) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 296 (2) K
  • 0.35 × 0.31 × 0.27 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 1999 [triangle]) T min = 0.968, T max = 0.975
  • 3678 measured reflections
  • 2572 independent reflections
  • 1732 reflections with I > 2σ(I)
  • R int = 0.019

Refinement

  • R[F 2 > 2σ(F 2)] = 0.040
  • wR(F 2) = 0.123
  • S = 1.04
  • 2572 reflections
  • 202 parameters
  • H-atom parameters constrained
  • Δρmax = 0.18 e Å−3
  • Δρmin = −0.15 e Å−3

Data collection: SMART (Bruker, 1999 [triangle]); cell refinement: SAINT-Plus (Bruker, 1999 [triangle]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808010672/im2059sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808010672/im2059Isup2.hkl

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

Acknowledgments

The author is grateful for financial support from the Science and Technology Postgraduate Project of Weinan Teachers University, China (No. 08YKZ006)

supplementary crystallographic information

Comment

The isoflavone derivative formononetin (4'-methoxy-7-hydroxyisoflavone) displays a wide range of biological activities, such as antioxidant effect (Jha et al., 1985), inhibiting cardiovascular disease (Potter et al., 1995; Sirtori et al., 1995) and balancing women's hormones (Cassidy et al., 1994). The title compound 4'-methoxy-7-ethoxylisoflavone, (I), is a derivative of formononetin and has potential medical applications.

The title compound is composed of a benzopyranone core with a p-methoxyphenyl substituent in 3-position and an additional ethoxy group in 7-position (Fig. 1). The geometry of the isoflavone skeleton of (I) is similar to that of monoethyldaidzein (Zhang et al., 2005) with respect to most of the bond distances and angles. The atoms of the benzopyranone moiety, including ring A (C10,C11,C13–C16) and C (O3/C8—C12), display an almost coplanar configuration with a mean deviation to the least square plane of 0.0152 (17) Å. To minimize steric pressure, the two rigid ring systems, benzene ring B (C2—C7) and the benzopyranone moiety, are rotated by 41.76 (7)° with respect to each other. The methoxy group at atom C2 is nearly coplanar with the benzopyranone moiety, as indicated by the torsional angle C1—O1—C2—C3 = 4.6 (3)°; The ethoxy group at atom C14 is also nearly coplanar with the attached ring, the torsional angle C17—O4—C14—C13 being -7.9 (2)°.

A one-dimensional infinite chain is formed by two intermolecular hydrogen bonds of the C–H···O type (C9—H9···O2 and C16—H16···O3, Fig. 2, Table 1). This combination of hydrogen bonds generates R22(8) rings propagating as an infinite one-dimensional chain along a axis.

As shown in Fig. 3, two isoflavone skeletons arrange in an anti-parallel fashion with aromatic F-tape and T-tape stacking interactions linking two molecules into a dimeric structure. The two benzopyranone moieties stack with each other with a CgAC-CgAC* distance of 3.686 (2) Å (CgAC and CgAC* are the centres of benzopyranone moieties at (x, y, z) and (-x, 2 - y, -z), respectively). The interplanar spacing measures to 3.425 (2) Å. In addition, another T-tape stacking interaction between H18C and CgB* (the centroid of ring B at (-x, 2 - y, -z)) of 2.818 (3) Å is observed. Both distances obviously lie in the normal range of F-tape and T-tape π-π stacking interactions (Janiak, 2000). At the same time, the carbonyl oxygen atom O2 acts as a hydrogen bond acceptor towards H17B of a neighboring molecule also leading to the formation of a dimeric substructure. The intermolecular hydrogen bond C17—H17B···O2 together with the aromatic F-tape and T-tape stacking interactions assemble the chains mentioned above into a two-dimensional network structure.

Experimental

Formononetin (1.0 g) was dissolved into acetone (30 ml) and KOH (1 ml, 0.3%). Diethylsulfate (1 ml) was added dropwise to the solution under vigorous stirring. The mixture was stirred at room temperature for 3 h and then poured into water (50 ml). A white precipitation appeared, which was filtered after 4 h and terated with NaOH (50 ml, 2 mol/L) to remove traces of remaining formonetin. The precipitate was filtered and washed with water until the pH of the filtrate was 7 yielding the title compound, 4'-methoxy-7-ethoxylisoflavone (yield: 82.4%). Crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of the solvent from an ethanolic solution after 3 d at room temperature.

Refinement

H atoms bound to O atoms were found in difference maps and refined using a riding model. H atoms bound to C atoms were placed in calculated positions (C—H=0.93–0.97 Å) and refined using a riding model, allowing for free rotation of the rigid methyl groups. Uiso(H) values were constrained to be 1.2Ueq (attached atom) [1.5Ueq(C) for methyl H atoms].

Figures

Fig. 1.
The molecular structure of (I), showing the atom-numbering scheme and 30% probability displacement ellipsoids.
Fig. 2.
The one-dimensional chain formed via two intermolecular hydrogen bonds of the C–H···O type. Atoms marked with an asterisk (*) or a hash (#) are at the symmetry positions (-x + 1, y, z) and (x + 1, y, z), respectively.
Fig. 3.
The dimeric structure formed via aromatic F-tape and T-tape stacking interactions as well as another intermolecular hydrogen bond of the C–H···O type. Atoms marked with an asterisk (*) are at the symmetry positions (-x, ...

Crystal data

C18H16O4V = 736.5 (6) Å3
Mr = 296.31Z = 2
Triclinic, P1F000 = 312
Hall symbol: -P 1Dx = 1.336 Mg m3
a = 6.234 (3) ÅMo Kα radiation λ = 0.71073 Å
b = 10.257 (5) ÅCell parameters from 2633 reflections
c = 12.159 (6) ŵ = 0.09 mm1
α = 80.837 (7)ºT = 296 (2) K
β = 87.728 (8)ºHexagonal, colorless
γ = 73.653 (7)º0.35 × 0.31 × 0.27 mm

Data collection

Bruker SMART CCD area-detector diffractometer2572 independent reflections
Radiation source: fine-focus sealed tube1732 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.019
T = 296(2) Kθmax = 25.1º
[var phi] and ω scansh = −6→7
Absorption correction: multi-scan(SADABS; Bruker, 1999)k = −12→11
Tmin = 0.968, Tmax = 0.975l = −13→14
3678 measured reflections

Refinement

Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.040  w = 1/[σ2(Fo2) + (0.0722P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.123(Δ/σ)max < 0.001
S = 1.04Δρmax = 0.18 e Å3
2572 reflectionsΔρmin = −0.15 e Å3
202 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.021 (5)
Secondary atom site location: difference Fourier map

Special details

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)

xyzUiso*/Ueq
O10.4540 (2)0.17252 (13)0.40797 (10)0.0661 (4)
O2−0.17446 (17)0.70638 (13)0.09853 (9)0.0568 (4)
O30.36722 (16)0.77566 (12)−0.07427 (9)0.0501 (3)
O4−0.0813 (2)1.17079 (13)−0.30131 (10)0.0628 (4)
C10.6401 (4)0.1505 (2)0.48100 (17)0.0836 (7)
H1A0.77380.14510.43790.125*
H1B0.65680.06600.53140.125*
H1C0.61430.22540.52270.125*
C20.4019 (3)0.29134 (18)0.33118 (13)0.0518 (5)
C30.5249 (3)0.3858 (2)0.31458 (14)0.0574 (5)
H30.65050.37300.35830.069*
C40.4600 (3)0.49962 (18)0.23260 (13)0.0518 (5)
H40.54440.56220.22190.062*
C50.2730 (3)0.52354 (17)0.16568 (13)0.0432 (4)
C60.1484 (3)0.42862 (17)0.18588 (13)0.0459 (4)
H60.02020.44250.14390.055*
C70.2120 (3)0.31489 (18)0.26689 (13)0.0495 (4)
H70.12640.25290.27870.059*
C80.2177 (2)0.64102 (16)0.07294 (12)0.0403 (4)
C90.3870 (3)0.67076 (17)0.01147 (13)0.0459 (4)
H90.53030.61430.02940.055*
C100.1585 (2)0.85994 (16)−0.10328 (12)0.0413 (4)
C11−0.0298 (2)0.83924 (16)−0.04665 (12)0.0394 (4)
C12−0.0106 (2)0.72643 (17)0.04624 (12)0.0417 (4)
C130.1508 (3)0.96676 (18)−0.19021 (13)0.0480 (4)
H130.28070.9761−0.22690.058*
C14−0.0519 (3)1.05814 (17)−0.22079 (13)0.0476 (4)
C15−0.2471 (3)1.04083 (18)−0.16642 (14)0.0521 (5)
H15−0.38511.1025−0.18750.063*
C16−0.2340 (3)0.93317 (18)−0.08245 (14)0.0488 (4)
H16−0.36480.9219−0.04800.059*
C170.1156 (3)1.2050 (2)−0.34750 (15)0.0656 (5)
H17A0.19711.1364−0.39180.079*
H17B0.21311.2079−0.28820.079*
C180.0418 (4)1.3431 (2)−0.41900 (17)0.0805 (6)
H18A−0.04471.3373−0.48070.121*
H18B0.17061.3717−0.44630.121*
H18C−0.04791.4088−0.37570.121*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0788 (9)0.0575 (9)0.0569 (8)−0.0217 (7)−0.0114 (6)0.0143 (7)
O20.0417 (6)0.0653 (9)0.0612 (7)−0.0198 (6)0.0080 (5)0.0033 (6)
O30.0385 (6)0.0487 (8)0.0558 (7)−0.0100 (5)0.0055 (5)0.0082 (6)
O40.0693 (8)0.0575 (9)0.0555 (8)−0.0191 (7)−0.0097 (6)0.0146 (7)
C10.0906 (16)0.0762 (16)0.0733 (14)−0.0212 (12)−0.0252 (11)0.0223 (12)
C20.0603 (11)0.0489 (11)0.0432 (10)−0.0163 (9)0.0018 (8)0.0030 (8)
C30.0548 (11)0.0615 (13)0.0542 (11)−0.0196 (9)−0.0114 (8)0.0049 (9)
C40.0522 (10)0.0521 (11)0.0537 (10)−0.0233 (9)−0.0052 (8)0.0020 (9)
C50.0418 (9)0.0451 (10)0.0433 (9)−0.0149 (7)0.0017 (7)−0.0036 (8)
C60.0458 (9)0.0490 (11)0.0444 (9)−0.0171 (8)0.0007 (7)−0.0045 (8)
C70.0540 (10)0.0490 (11)0.0486 (10)−0.0224 (8)0.0041 (7)−0.0034 (8)
C80.0405 (8)0.0411 (10)0.0409 (8)−0.0158 (7)−0.0009 (6)−0.0034 (7)
C90.0392 (9)0.0413 (10)0.0524 (10)−0.0088 (7)−0.0007 (7)0.0029 (8)
C100.0398 (8)0.0418 (10)0.0410 (9)−0.0107 (7)−0.0005 (6)−0.0036 (8)
C110.0387 (8)0.0400 (10)0.0397 (8)−0.0126 (7)−0.0012 (6)−0.0037 (7)
C120.0401 (9)0.0460 (10)0.0426 (9)−0.0174 (7)0.0009 (7)−0.0079 (8)
C130.0492 (10)0.0486 (11)0.0455 (10)−0.0167 (8)0.0046 (7)−0.0007 (8)
C140.0568 (10)0.0455 (11)0.0397 (9)−0.0159 (8)−0.0069 (7)0.0001 (8)
C150.0439 (10)0.0488 (11)0.0606 (11)−0.0107 (8)−0.0107 (8)−0.0007 (9)
C160.0387 (9)0.0521 (11)0.0556 (10)−0.0153 (8)−0.0010 (7)−0.0039 (9)
C170.0787 (13)0.0561 (13)0.0550 (11)−0.0167 (10)0.0116 (9)0.0053 (10)
C180.1102 (17)0.0565 (14)0.0655 (13)−0.0205 (12)0.0130 (12)0.0099 (11)

Geometric parameters (Å, °)

O1—C21.379 (2)C7—H70.9300
O1—C11.433 (2)C8—C91.346 (2)
O2—C121.2307 (18)C8—C121.464 (2)
O3—C91.3557 (19)C9—H90.9300
O3—C101.3675 (18)C10—C131.388 (2)
O4—C141.365 (2)C10—C111.388 (2)
O4—C171.439 (2)C11—C161.399 (2)
C1—H1A0.9600C11—C121.465 (2)
C1—H1B0.9600C13—C141.369 (2)
C1—H1C0.9600C13—H130.9300
C2—C31.383 (3)C14—C151.404 (2)
C2—C71.387 (2)C15—C161.366 (2)
C3—C41.384 (2)C15—H150.9300
C3—H30.9300C16—H160.9300
C4—C51.390 (2)C17—C181.499 (3)
C4—H40.9300C17—H17A0.9700
C5—C61.395 (2)C17—H17B0.9700
C5—C81.485 (2)C18—H18A0.9600
C6—C71.376 (2)C18—H18B0.9600
C6—H60.9300C18—H18C0.9600
C2—O1—C1117.47 (14)O3—C10—C13115.53 (13)
C9—O3—C10118.54 (12)O3—C10—C11121.09 (14)
C14—O4—C17117.60 (14)C13—C10—C11123.36 (15)
O1—C1—H1A109.5C10—C11—C16116.07 (15)
O1—C1—H1B109.5C10—C11—C12120.89 (14)
H1A—C1—H1B109.5C16—C11—C12123.03 (13)
O1—C1—H1C109.5O2—C12—C8122.74 (15)
H1A—C1—H1C109.5O2—C12—C11122.28 (15)
H1B—C1—H1C109.5C8—C12—C11114.98 (12)
O1—C2—C3124.71 (16)C14—C13—C10118.61 (15)
O1—C2—C7116.29 (15)C14—C13—H13120.7
C3—C2—C7118.99 (17)C10—C13—H13120.7
C2—C3—C4119.61 (16)O4—C14—C13124.46 (15)
C2—C3—H3120.2O4—C14—C15115.48 (16)
C4—C3—H3120.2C13—C14—C15120.05 (16)
C3—C4—C5122.27 (15)C16—C15—C14119.81 (16)
C3—C4—H4118.9C16—C15—H15120.1
C5—C4—H4118.9C14—C15—H15120.1
C4—C5—C6117.05 (15)C15—C16—C11122.07 (14)
C4—C5—C8120.86 (13)C15—C16—H16119.0
C6—C5—C8122.00 (14)C11—C16—H16119.0
C7—C6—C5121.12 (15)O4—C17—C18107.74 (16)
C7—C6—H6119.4O4—C17—H17A110.2
C5—C6—H6119.4C18—C17—H17A110.2
C6—C7—C2120.92 (15)O4—C17—H17B110.2
C6—C7—H7119.5C18—C17—H17B110.2
C2—C7—H7119.5H17A—C17—H17B108.5
C9—C8—C12118.69 (15)C17—C18—H18A109.5
C9—C8—C5118.03 (14)C17—C18—H18B109.5
C12—C8—C5123.28 (12)H18A—C18—H18B109.5
C8—C9—O3125.81 (15)C17—C18—H18C109.5
C8—C9—H9117.1H18A—C18—H18C109.5
O3—C9—H9117.1H18B—C18—H18C109.5
C1—O1—C2—C34.6 (3)O3—C10—C11—C120.1 (2)
C1—O1—C2—C7−175.63 (15)C13—C10—C11—C12−178.56 (13)
O1—C2—C3—C4178.07 (15)C9—C8—C12—O2−179.79 (15)
C7—C2—C3—C4−1.7 (3)C5—C8—C12—O2−0.5 (2)
C2—C3—C4—C50.3 (3)C9—C8—C12—C11−0.6 (2)
C3—C4—C5—C61.2 (2)C5—C8—C12—C11178.64 (13)
C3—C4—C5—C8−175.40 (14)C10—C11—C12—O2179.37 (14)
C4—C5—C6—C7−1.5 (2)C16—C11—C12—O20.6 (2)
C8—C5—C6—C7175.13 (14)C10—C11—C12—C80.2 (2)
C5—C6—C7—C20.1 (2)C16—C11—C12—C8−178.60 (14)
O1—C2—C7—C6−178.32 (13)O3—C10—C13—C14−177.57 (13)
C3—C2—C7—C61.5 (3)C11—C10—C13—C141.2 (2)
C4—C5—C8—C939.5 (2)C17—O4—C14—C13−7.9 (2)
C6—C5—C8—C9−136.98 (16)C17—O4—C14—C15170.69 (14)
C4—C5—C8—C12−139.76 (16)C10—C13—C14—O4176.99 (14)
C6—C5—C8—C1243.8 (2)C10—C13—C14—C15−1.6 (2)
C12—C8—C9—O30.8 (2)O4—C14—C15—C16−178.21 (13)
C5—C8—C9—O3−178.50 (13)C13—C14—C15—C160.5 (2)
C10—O3—C9—C8−0.5 (2)C14—C15—C16—C111.1 (2)
C9—O3—C10—C13178.77 (13)C10—C11—C16—C15−1.5 (2)
C9—O3—C10—C110.0 (2)C12—C11—C16—C15177.38 (14)
O3—C10—C11—C16179.00 (13)C14—O4—C17—C18−170.80 (14)
C13—C10—C11—C160.3 (2)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C9—H9···O2i0.932.523.105 (2)121
C16—H16···O3ii0.932.603.315 (2)134
C17—H17B···O2iii0.972.583.358 (3)138

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IM2059).

References

  • Bruker (1999). SMART, SAINT-Plus and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Cassidy, A., Bingham, S. & Setchell, K. D. (1994). Am. J. Clin. Nutr.60, 333–340. [PubMed]
  • Janiak, C. (2000). J. Chem. Soc. Dalton Trans. pp. 3885–3896.
  • Jha, H. C., von Recklinghausen, G. & Zilliken, F. (1985). Biochem. Pharmacol.34, 1367–1372. [PubMed]
  • Potter, S. M. (1995). J. Nutr.125, 606S–611S. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Sirtori, C. R., Lovati, M. R. & Manzoni, C. (1995). J. Nutr.125, 598S–605S. [PubMed]
  • Zhang, Z. T., Wang, Q.-Y., He, Y. & Yu, K.-B. (2005). J. Chem. Crystallogr.35, 89–94.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography