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Acta Crystallogr Sect E Struct Rep Online. 2010 April 1; 66(Pt 4): o988.
Published online 2010 March 31. doi:  10.1107/S1600536810011360
PMCID: PMC2983982

6,8-Diiodo-5,7-dimeth­oxy-4-methyl­coumarin

Abstract

In the title compound, C12H10I2O4, the meth­oxy groups are twisted considerably with respect to the plane of the aromatic ring [CH3—O—C—C torsion angles = −85.9 (3) and −92.8 (3)°]. In the crystal, mol­ecules are linked by weak C—H(...)O hydrogen bonds and O(...)I contacts [3.194 (2) Å].

Related literature

For the medicinal applications of coumarin derivatives, see: Lin et al. (2006 [triangle]); Massimo et al. (2003 [triangle]); Tyagi et al. (2003 [triangle]); Nawrot-Modranka et al. (2006 [triangle]); Sardari et al. (1999 [triangle]); Huang et al. (2005 [triangle]); Elinos-Baez et al. (2005 [triangle]). For the synthesis of the title compound, see: Ali & Ilyas (1986 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-0o988-scheme1.jpg

Experimental

Crystal data

  • C12H10I2O4
  • M r = 472.00
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o988-efi1.jpg
  • a = 10.8681 (2) Å
  • b = 9.1179 (2) Å
  • c = 17.2315 (3) Å
  • β = 125.395 (1)°
  • V = 1391.95 (5) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 4.52 mm−1
  • T = 293 K
  • 0.30 × 0.24 × 0.16 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003 [triangle]) T min = 0.396, T max = 0.485
  • 27048 measured reflections
  • 3928 independent reflections
  • 3453 reflections with I > 2σ(I)
  • R int = 0.022

Refinement

  • R[F 2 > 2σ(F 2)] = 0.023
  • wR(F 2) = 0.055
  • S = 1.06
  • 3928 reflections
  • 166 parameters
  • H-atom parameters constrained
  • Δρmax = 0.71 e Å−3
  • Δρmin = −0.96 e Å−3

Data collection: APEX2 (Bruker, 2003 [triangle]); cell refinement: SAINT (Bruker, 2003 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2009 [triangle]); software used to prepare material for publication: SHELXL97.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810011360/bt5225sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810011360/bt5225Isup2.hkl

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

Acknowledgments

This work was supported by the Fundação para a Ciência e a Tecnologia (FCT) under scholarship SFRH/BD/38387/2008.

supplementary crystallographic information

Comment

Coumarin is the simplest member of the group of oxygen heterocyclics called benzo-2-pyrone. Coumarins are an important class of compounds due to their presence in natural products as well as their medicinal applications such as anti-inflammatory (Lin et al., 2006), anti-viral (Massimo et al., 2003), antioxidant (Tyagi et al., 2003), antibacterial (Nawrot-Modranka et al., 2006), antifungal (Sardari et al., 1999), anti-HIV (Huang et al., 2005) and as anti-carcinogenic (Elinos-Baez et al., 2005). Besides the wide spectrum of biological applications of coumarin and its derivatives, the chemical literature also embodies their applications as cosmetics, optical brightening agents, and laser dyes. A recent report has revealed the anion sensing ability of some coumarin derivatives. Among various coumarin derivatives, recent pharmacological evaluation of iodocoumarins as cannabinoid receptor antagonists and inverse agonists has been done. Iodocoumarins such as 8-iodo-7-hydroxycoumarin exhibited moderate activity and 8-iodo-5,7-dihydroxycoumarin displayed good antimicrobial properties with MIC values <100 µg/ml. Also, iodocoumarins had been successfully used for the optimization of reaction conditions and kinetic studies in high throughput format. Because of the biological and pharmaceutical importance of iodocoumarins, several protocols for the synthesis have been reported.

In the light of the mentioned above we planned to synthesize iodocoumarins by reaction of 5,7-dimethoxy-4-methylcoumarin with iodine in basic media (Ali & Ilyas, 1986).

In the molecule of the title compound (Fig. 1), the best plane through the aromatic ring shows an r.m.s. deviation of 0.0154 Å; the O1—C2—C3—C4—C10—C9 ring shows a slightly larger deviation from planarity, with an r.m.s. deviation of 0.0189 Å. The angle between these two planes is 4.96 (11)°.

The C2 atom of the carbonyl group has a distorted trigonal geometry with O2—C2—O1 [116.6 (2)°] and O2—C2—C3 [126.5 (2)°] deviating significantly from the ideal sp2 value of 120°.

The methoxy groups are considerably twisted with respect to the plane of the aromatic ring as indicated by the torsion angles C12—O3—C5—C6 [-85.9 (3)°] and C13—O4—C7—C6 [90.7 (3)°]. The iodine atoms are almost in the plane of the benzene ring and the methyl group is slightly out of the pyrone ring plane.

The molecules are linked across an inversion centre by one weak hydrogen bond of the C—H···O type (Fig. 2, Table 2).

Experimental

To a stirred solution of 5,7-dimethoxy-4-methylcoumarin (2.20 g, 10 mmol) in 15-20 ml of methanol containing 8.2 g KOH was dropwise added to a solution of I2 (2.56 g, 10 mmol) over a period of 30 min and stirred at room temperature for about 2 hours. The reaction mixture was poured into water and residual iodine was removed by washing with sodium thiosulphate. On treatment with sodium thiosulphate we obtained a precipitate which was filtered and crystallized with CHCl3—MeOH as white crystals (300 mg, m.p. 490 K).

Refinement

All H atoms were located in a difference Fourier synthesis, placed in calculated positions and refined as riding on their parent atoms, using SHELXL97 (Sheldrick, 2008) defaults.

Figures

Fig. 1.
A plot of the title compound. Displacement ellipsoids are drawn at the 50% probability level.
Fig. 2.
A packing diagram for the title compound, viewed down the a axis, with the hydrogen bonds depicted by dashed lines.

Crystal data

C12H10I2O4F(000) = 880
Mr = 472.00Dx = 2.252 Mg m3
Monoclinic, P21/cMelting point: 490 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 10.8681 (2) ÅCell parameters from 7934 reflections
b = 9.1179 (2) Åθ = 2.4–29.5°
c = 17.2315 (3) ŵ = 4.52 mm1
β = 125.395 (1)°T = 293 K
V = 1391.95 (5) Å3Irregular block, pale yellow
Z = 40.30 × 0.24 × 0.16 mm

Data collection

Bruker APEXII CCD area-detector diffractometer3928 independent reflections
Radiation source: fine-focus sealed tube3453 reflections with I > 2σ(I)
graphiteRint = 0.022
[var phi] and ω scansθmax = 29.7°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)h = −14→15
Tmin = 0.396, Tmax = 0.485k = −12→12
27048 measured reflectionsl = −24→23

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.023Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.055H-atom parameters constrained
S = 1.06w = 1/[σ2(Fo2) + (0.0226P)2 + 1.1738P] where P = (Fo2 + 2Fc2)/3
3928 reflections(Δ/σ)max = 0.001
166 parametersΔρmax = 0.71 e Å3
0 restraintsΔρmin = −0.96 e Å3

Special details

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 > 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
I10.51053 (2)0.82363 (2)0.156895 (15)0.05749 (7)
I20.11277 (2)0.593603 (19)0.266073 (13)0.04546 (6)
O10.06827 (19)0.35475 (17)0.12276 (12)0.0353 (3)
O2−0.0507 (2)0.1432 (2)0.07590 (17)0.0548 (5)
O30.39384 (18)0.53122 (19)0.03873 (12)0.0383 (4)
O40.3379 (2)0.79647 (18)0.25451 (12)0.0434 (4)
C80.1966 (3)0.5766 (2)0.18397 (16)0.0317 (4)
C70.2959 (3)0.6823 (2)0.19268 (16)0.0337 (5)
C60.3586 (3)0.6668 (2)0.14197 (17)0.0352 (5)
C50.3273 (2)0.5453 (3)0.08510 (15)0.0318 (4)
C100.2315 (2)0.4324 (2)0.07795 (15)0.0297 (4)
C90.1647 (2)0.4549 (2)0.12598 (15)0.0294 (4)
C40.2056 (3)0.2920 (2)0.03026 (16)0.0352 (5)
C30.1095 (3)0.1972 (3)0.02911 (18)0.0395 (5)
H30.09050.1087−0.00280.047*
C20.0351 (3)0.2248 (3)0.07400 (18)0.0379 (5)
C130.2462 (4)0.9256 (3)0.2126 (2)0.0621 (8)
H13A0.23930.95130.15620.093*
H13B0.29111.00510.25730.093*
H13C0.14700.90660.19640.093*
C120.3139 (3)0.6047 (3)−0.05204 (19)0.0497 (6)
H12A0.21530.5623−0.09360.075*
H12B0.36870.5937−0.07970.075*
H12C0.30440.7070−0.04330.075*
C110.2873 (4)0.2436 (3)−0.0117 (2)0.0582 (8)
H11A0.26070.1440−0.03310.087*
H11B0.39420.25020.03570.087*
H11C0.25920.3057−0.06460.087*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
I10.05881 (12)0.05243 (11)0.06135 (13)−0.02587 (9)0.03486 (10)−0.01030 (8)
I20.05746 (11)0.04523 (10)0.04782 (10)−0.00537 (7)0.03859 (9)−0.01056 (7)
O10.0400 (9)0.0303 (7)0.0438 (9)−0.0055 (6)0.0290 (8)−0.0069 (7)
O20.0650 (13)0.0391 (9)0.0823 (15)−0.0165 (9)0.0552 (12)−0.0145 (10)
O30.0370 (8)0.0458 (9)0.0384 (9)0.0023 (7)0.0255 (8)0.0035 (7)
O40.0572 (11)0.0325 (8)0.0355 (9)−0.0062 (8)0.0239 (8)−0.0092 (7)
C80.0355 (11)0.0304 (10)0.0307 (10)0.0031 (8)0.0200 (9)−0.0015 (8)
C70.0380 (12)0.0277 (10)0.0286 (10)−0.0006 (8)0.0154 (9)−0.0023 (8)
C60.0355 (11)0.0325 (11)0.0330 (11)−0.0057 (9)0.0172 (10)0.0007 (9)
C50.0299 (10)0.0357 (11)0.0291 (10)0.0019 (8)0.0167 (9)0.0032 (8)
C100.0307 (10)0.0294 (10)0.0271 (10)0.0008 (8)0.0157 (9)−0.0008 (8)
C90.0293 (10)0.0280 (9)0.0296 (10)0.0003 (8)0.0162 (9)−0.0005 (8)
C40.0400 (12)0.0334 (11)0.0338 (11)0.0017 (9)0.0224 (10)−0.0036 (9)
C30.0477 (14)0.0299 (11)0.0453 (13)−0.0041 (10)0.0294 (12)−0.0077 (9)
C20.0409 (12)0.0290 (10)0.0453 (13)−0.0031 (9)0.0257 (11)−0.0049 (9)
C130.093 (2)0.0340 (13)0.0625 (19)0.0072 (15)0.0471 (19)−0.0025 (12)
C120.0480 (15)0.0696 (18)0.0379 (13)0.0039 (13)0.0285 (12)0.0077 (12)
C110.078 (2)0.0493 (16)0.077 (2)−0.0089 (15)0.0618 (19)−0.0206 (15)

Geometric parameters (Å, °)

I1—C62.084 (2)C10—C41.458 (3)
I2—C82.085 (2)C4—C31.347 (3)
O1—C91.367 (3)C4—C111.500 (3)
O1—C21.375 (3)C3—C21.428 (3)
O2—C21.208 (3)C3—H30.9300
O3—C51.359 (3)C13—H13A0.9600
O3—C121.441 (3)C13—H13B0.9600
O4—C71.365 (3)C13—H13C0.9600
O4—C131.438 (3)C12—H12A0.9600
C8—C71.389 (3)C12—H12B0.9600
C8—C91.396 (3)C12—H12C0.9600
C7—C61.392 (3)C11—H11A0.9600
C6—C51.385 (3)C11—H11B0.9600
C5—C101.418 (3)C11—H11C0.9600
C10—C91.397 (3)
C9—O1—C2121.60 (18)C4—C3—C2123.8 (2)
C5—O3—C12113.74 (18)C4—C3—H3118.1
C7—O4—C13114.3 (2)C2—C3—H3118.1
C7—C8—C9118.9 (2)O2—C2—O1116.6 (2)
C7—C8—I2119.53 (16)O2—C2—C3126.5 (2)
C9—C8—I2121.34 (16)O1—C2—C3116.9 (2)
O4—C7—C8120.0 (2)O4—C13—H13A109.5
O4—C7—C6120.2 (2)O4—C13—H13B109.5
C8—C7—C6119.6 (2)H13A—C13—H13B109.5
C5—C6—C7121.1 (2)O4—C13—H13C109.5
C5—C6—I1119.26 (17)H13A—C13—H13C109.5
C7—C6—I1119.58 (16)H13B—C13—H13C109.5
O3—C5—C6119.7 (2)O3—C12—H12A109.5
O3—C5—C10119.6 (2)O3—C12—H12B109.5
C6—C5—C10120.6 (2)H12A—C12—H12B109.5
C9—C10—C5116.74 (19)O3—C12—H12C109.5
C9—C10—C4117.8 (2)H12A—C12—H12C109.5
C5—C10—C4125.4 (2)H12B—C12—H12C109.5
O1—C9—C10121.85 (19)C4—C11—H11A109.5
O1—C9—C8115.25 (19)C4—C11—H11B109.5
C10—C9—C8122.8 (2)H11A—C11—H11B109.5
C3—C4—C10117.8 (2)C4—C11—H11C109.5
C3—C4—C11118.3 (2)H11A—C11—H11C109.5
C10—C4—C11123.7 (2)H11B—C11—H11C109.5
C13—O4—C7—C8−92.8 (3)C2—O1—C9—C101.7 (3)
C13—O4—C7—C690.7 (3)C2—O1—C9—C8−175.3 (2)
C9—C8—C7—O4−175.0 (2)C5—C10—C9—O1178.85 (19)
I2—C8—C7—O4−0.1 (3)C4—C10—C9—O1−5.2 (3)
C9—C8—C7—C61.5 (3)C5—C10—C9—C8−4.3 (3)
I2—C8—C7—C6176.40 (17)C4—C10—C9—C8171.7 (2)
O4—C7—C6—C5174.5 (2)C7—C8—C9—O1178.8 (2)
C8—C7—C6—C5−2.0 (3)I2—C8—C9—O14.0 (3)
O4—C7—C6—I1−2.4 (3)C7—C8—C9—C101.7 (3)
C8—C7—C6—I1−178.96 (17)I2—C8—C9—C10−173.05 (16)
C12—O3—C5—C6−85.9 (3)C9—C10—C4—C35.1 (3)
C12—O3—C5—C1096.7 (3)C5—C10—C4—C3−179.3 (2)
C7—C6—C5—O3−178.0 (2)C9—C10—C4—C11−170.8 (3)
I1—C6—C5—O3−1.1 (3)C5—C10—C4—C114.8 (4)
C7—C6—C5—C10−0.7 (3)C10—C4—C3—C2−1.8 (4)
I1—C6—C5—C10176.25 (16)C11—C4—C3—C2174.3 (3)
O3—C5—C10—C9−178.92 (19)C9—O1—C2—O2179.6 (2)
C6—C5—C10—C93.7 (3)C9—O1—C2—C31.7 (3)
O3—C5—C10—C45.4 (3)C4—C3—C2—O2−179.2 (3)
C6—C5—C10—C4−171.9 (2)C4—C3—C2—O1−1.7 (4)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C3—H3···O2i0.932.533.460 (3)175

Symmetry codes: (i) −x, −y, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5225).

References

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