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In the biologically active title compound, C19H14Br2O, a derivative of curcumin, the dihedral angle between the aromatic ring planes is 59.78 (19)°.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807036185/hb2485sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807036185/hb2485Isup2.hkl
Contains datablock I

CCDC reference: 657863

Key indicators

  • Single-crystal X-ray study
  • T = 298 K
  • Mean [sigma](C-C) = 0.005 Å
  • R factor = 0.037
  • wR factor = 0.095
  • Data-to-parameter ratio = 14.4

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT431_ALERT_2_C Short Inter HL..A Contact Br1 .. O1 .. 3.14 Ang.
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

The title compound, (2E, 5E)-2,5-bis(2-bromobenzylidene) cyclopentanone, (I), derived from curcumin, is a biologically active compound. Curcumin has been found to possess a variety of pharmaceutical applications, for example, inhibiting carcinogen-induced mutations and the formation of tumour, antioxidation, anti-inflammation, anti-virus, decreasing total cholesterol and LDL cholesterol level (Began et al., 1999; Kawamon et al., 1999; Poorichaya et al., 2007). However, curcumin is unstable at a pH over 6.5, due to the presence of the methylene group. Omitting the methylene group and one carbonyl group, therefore, some mono-carbonyl curcumin analogues without the central methylene functional groups, were synthesized and their biological activity in vitro were evaluated. Part of bisbenzylidene cyclopentanone derivatives showed stronger bio-activity than curcumin (Artico et al., 1998; Butcher et al., 2007; Subbagh et al., 2000). The crystal structure of 2,5-bis(3,4-dimethoxybenzylidene) cyclopentanone (Butcher et al., 2007) has been reported. As part of our research in this area, we synthesized the title compound C19H14Br2O and describe its structure here. Its geometrical parameters are normal; the dihedral angle between the aromatic ring planes is 59.78 (19)°.

Related literature top

For related literature, see: Artico et al. (1998); Began et al. (1999); Butcher, Jasinski, Narayana et al. (2007); Butcher, Jasinski, Sarojini et al. (2007); Kawamori et al. (1999); Poorichaya et al. (2007); Subbagh et al. (2000).

Experimental top

To a solution of 15 mmol 2-bromobenzaldehyde in MeOH (10 ml) was added 7.5 mmol cyclopentanone. The solution was stirred at room temperature for 20 min, followed by added dropwise 20% (w/v) NaOH (1.5 ml, 7.5 mmol). The mixture was stirred at RT and monitored with TLC. When the reaction finished, the residue was poured into saturated NH4Cl solution and filtered. The precipitate was washed and purified by chromatography over silica gel using CH2Cl2/CH3OH as the eluent to afford the pure product (yield: 65%). Single crystals of (I) were grown in a CH2Cl2–CH3OH mixture (8:2 v/v) by slow evaporation (mp 436–437 K). 1H-NMR (CDCl3): 1.93 (4H, s, CH2—CH2), 7.23 (2H, m, Ar—H6), 7.37 (2H, m, Ar—H4), 7.52 (2H, m, Ar—H5), 7.66 (2H, m, Ar—H3), 7.86 (2H, s, Ar—CH=C2). ESI-MS m/z: 418.94 (M+1)+, calcd for C19H14Br2O: 418.12.

Refinement top

The H atoms were positioned geometrically (C—H = 0.93–0.97 Å) and refined as riding with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C).

Structure description top

The title compound, (2E, 5E)-2,5-bis(2-bromobenzylidene) cyclopentanone, (I), derived from curcumin, is a biologically active compound. Curcumin has been found to possess a variety of pharmaceutical applications, for example, inhibiting carcinogen-induced mutations and the formation of tumour, antioxidation, anti-inflammation, anti-virus, decreasing total cholesterol and LDL cholesterol level (Began et al., 1999; Kawamon et al., 1999; Poorichaya et al., 2007). However, curcumin is unstable at a pH over 6.5, due to the presence of the methylene group. Omitting the methylene group and one carbonyl group, therefore, some mono-carbonyl curcumin analogues without the central methylene functional groups, were synthesized and their biological activity in vitro were evaluated. Part of bisbenzylidene cyclopentanone derivatives showed stronger bio-activity than curcumin (Artico et al., 1998; Butcher et al., 2007; Subbagh et al., 2000). The crystal structure of 2,5-bis(3,4-dimethoxybenzylidene) cyclopentanone (Butcher et al., 2007) has been reported. As part of our research in this area, we synthesized the title compound C19H14Br2O and describe its structure here. Its geometrical parameters are normal; the dihedral angle between the aromatic ring planes is 59.78 (19)°.

For related literature, see: Artico et al. (1998); Began et al. (1999); Butcher, Jasinski, Narayana et al. (2007); Butcher, Jasinski, Sarojini et al. (2007); Kawamori et al. (1999); Poorichaya et al. (2007); Subbagh et al. (2000).

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) shoiwng 30% displacement ellipsoids for the non-hydrogen atoms.
(2E,5E)-2,5-Bis(2-bromobenzylidene)cyclopentanone top
Crystal data top
C19H14Br2OF(000) = 824
Mr = 418.12Dx = 1.714 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2746 reflections
a = 8.6504 (8) Åθ = 2.5–24.8°
b = 8.4789 (8) ŵ = 5.00 mm1
c = 22.126 (2) ÅT = 298 K
β = 93.119 (2)°Block, colourless
V = 1620.5 (3) Å30.33 × 0.20 × 0.19 mm
Z = 4
Data collection top
Bruker APEX CCD area-detector
diffractometer
2857 independent reflections
Radiation source: fine-focus sealed tube2292 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
φ and ω scansθmax = 25.0°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
h = 1010
Tmin = 0.309, Tmax = 0.391k = 109
8202 measured reflectionsl = 2621
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)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0424P)2 + 1.7145P]
where P = (Fo2 + 2Fc2)/3
2857 reflections(Δ/σ)max = 0.001
199 parametersΔρmax = 0.69 e Å3
0 restraintsΔρmin = 0.96 e Å3
Crystal data top
C19H14Br2OV = 1620.5 (3) Å3
Mr = 418.12Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.6504 (8) ŵ = 5.00 mm1
b = 8.4789 (8) ÅT = 298 K
c = 22.126 (2) Å0.33 × 0.20 × 0.19 mm
β = 93.119 (2)°
Data collection top
Bruker APEX CCD area-detector
diffractometer
2857 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
2292 reflections with I > 2σ(I)
Tmin = 0.309, Tmax = 0.391Rint = 0.024
8202 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0370 restraints
wR(F2) = 0.095H-atom parameters constrained
S = 1.04Δρmax = 0.69 e Å3
2857 reflectionsΔρmin = 0.96 e Å3
199 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
Br10.33176 (5)0.34999 (5)1.049559 (18)0.05462 (16)
Br21.11065 (5)0.18597 (7)0.77243 (3)0.0767 (2)
O10.6144 (3)0.3500 (3)0.86877 (12)0.0550 (7)
C10.2692 (4)0.1396 (4)1.02839 (17)0.0432 (8)
C20.3168 (4)0.0684 (4)0.97524 (16)0.0410 (8)
C30.2662 (4)0.0868 (5)0.96568 (17)0.0505 (9)
H30.29420.13960.93110.061*
C40.1760 (5)0.1643 (5)1.00582 (19)0.0575 (11)
H40.14480.26770.99820.069*
C50.1322 (5)0.0883 (5)1.05707 (19)0.0565 (11)
H50.07080.14031.08400.068*
C60.1786 (4)0.0636 (5)1.06871 (17)0.0501 (10)
H60.14940.11501.10340.060*
C70.4145 (4)0.1517 (4)0.93415 (16)0.0421 (8)
H70.44640.25090.94770.050*
C80.4664 (4)0.1114 (4)0.88048 (16)0.0389 (8)
C90.5734 (4)0.2199 (4)0.85095 (15)0.0395 (8)
C100.6236 (4)0.1421 (4)0.79538 (15)0.0370 (8)
C110.5245 (5)0.0008 (5)0.78286 (17)0.0502 (9)
H11A0.58730.08980.77170.060*
H11B0.44770.01990.75020.060*
C120.4453 (4)0.0347 (4)0.84245 (16)0.0431 (8)
H12A0.33620.05690.83430.052*
H12B0.49310.12480.86300.052*
C130.7469 (4)0.1931 (4)0.76776 (16)0.0405 (8)
H130.79690.28090.78470.049*
C140.8131 (4)0.1269 (4)0.71370 (16)0.0398 (8)
C150.9727 (4)0.1184 (4)0.70760 (18)0.0479 (9)
C161.0353 (5)0.0583 (5)0.6568 (2)0.0603 (11)
H161.14220.05310.65420.072*
C170.9385 (6)0.0059 (5)0.6099 (2)0.0696 (14)
H170.98010.03460.57520.083*
C180.7796 (6)0.0129 (5)0.61369 (19)0.0634 (12)
H180.71430.02130.58150.076*
C190.7185 (5)0.0710 (5)0.66541 (16)0.0504 (10)
H190.61160.07300.66820.060*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0688 (3)0.0473 (2)0.0492 (2)0.00208 (19)0.01663 (19)0.00735 (18)
Br20.0447 (3)0.0869 (4)0.0983 (4)0.0006 (2)0.0019 (2)0.0170 (3)
O10.0654 (18)0.0410 (16)0.0605 (17)0.0107 (13)0.0218 (14)0.0135 (13)
C10.0397 (19)0.044 (2)0.046 (2)0.0049 (17)0.0023 (16)0.0012 (16)
C20.0358 (19)0.045 (2)0.0428 (19)0.0014 (16)0.0020 (15)0.0018 (16)
C30.052 (2)0.052 (2)0.048 (2)0.005 (2)0.0111 (18)0.0045 (18)
C40.060 (3)0.055 (3)0.059 (3)0.012 (2)0.008 (2)0.002 (2)
C50.047 (2)0.064 (3)0.060 (3)0.009 (2)0.0128 (19)0.014 (2)
C60.044 (2)0.061 (3)0.046 (2)0.0028 (19)0.0086 (17)0.0020 (19)
C70.0402 (19)0.0360 (19)0.050 (2)0.0002 (16)0.0062 (16)0.0028 (16)
C80.0357 (18)0.0379 (19)0.043 (2)0.0024 (15)0.0042 (15)0.0032 (15)
C90.0398 (19)0.039 (2)0.0397 (19)0.0021 (16)0.0039 (15)0.0032 (16)
C100.0344 (18)0.0375 (19)0.0394 (18)0.0031 (15)0.0039 (14)0.0026 (15)
C110.050 (2)0.050 (2)0.051 (2)0.0075 (19)0.0114 (17)0.0139 (18)
C120.043 (2)0.042 (2)0.045 (2)0.0052 (16)0.0040 (16)0.0075 (16)
C130.043 (2)0.0348 (19)0.0439 (19)0.0020 (16)0.0032 (16)0.0042 (15)
C140.044 (2)0.0315 (18)0.045 (2)0.0043 (16)0.0082 (16)0.0014 (15)
C150.048 (2)0.037 (2)0.060 (2)0.0021 (17)0.0161 (18)0.0045 (17)
C160.068 (3)0.048 (3)0.068 (3)0.007 (2)0.033 (2)0.008 (2)
C170.104 (4)0.052 (3)0.056 (3)0.009 (3)0.042 (3)0.001 (2)
C180.098 (4)0.048 (3)0.045 (2)0.006 (2)0.012 (2)0.0036 (19)
C190.057 (2)0.046 (2)0.049 (2)0.0000 (19)0.0094 (19)0.0020 (18)
Geometric parameters (Å, º) top
Br1—C11.915 (4)C10—C131.330 (5)
Br2—C151.904 (4)C10—C111.501 (5)
O1—C91.217 (4)C11—C121.545 (5)
C1—C61.379 (5)C11—H11A0.9700
C1—C21.403 (5)C11—H11B0.9700
C2—C31.400 (5)C12—H12A0.9700
C2—C71.457 (5)C12—H12B0.9700
C3—C41.380 (6)C13—C141.466 (5)
C3—H30.9300C13—H130.9300
C4—C51.375 (6)C14—C191.393 (5)
C4—H40.9300C14—C151.396 (5)
C5—C61.369 (6)C15—C161.372 (5)
C5—H50.9300C16—C171.372 (7)
C6—H60.9300C16—H160.9300
C7—C81.337 (5)C17—C181.384 (7)
C7—H70.9300C17—H170.9300
C8—C91.482 (5)C18—C191.377 (5)
C8—C121.503 (5)C18—H180.9300
C9—C101.481 (5)C19—H190.9300
C6—C1—C2123.0 (4)C12—C11—H11A110.6
C6—C1—Br1116.1 (3)C10—C11—H11B110.6
C2—C1—Br1120.9 (3)C12—C11—H11B110.6
C3—C2—C1115.3 (3)H11A—C11—H11B108.8
C3—C2—C7123.3 (3)C8—C12—C11106.1 (3)
C1—C2—C7121.4 (3)C8—C12—H12A110.5
C4—C3—C2122.3 (4)C11—C12—H12A110.5
C4—C3—H3118.9C8—C12—H12B110.5
C2—C3—H3118.9C11—C12—H12B110.5
C5—C4—C3119.9 (4)H12A—C12—H12B108.7
C5—C4—H4120.1C10—C13—C14127.5 (3)
C3—C4—H4120.1C10—C13—H13116.2
C6—C5—C4120.3 (4)C14—C13—H13116.2
C6—C5—H5119.8C19—C14—C15116.8 (3)
C4—C5—H5119.8C19—C14—C13121.1 (3)
C5—C6—C1119.3 (4)C15—C14—C13122.1 (3)
C5—C6—H6120.4C16—C15—C14122.4 (4)
C1—C6—H6120.4C16—C15—Br2118.0 (3)
C8—C7—C2131.7 (3)C14—C15—Br2119.6 (3)
C8—C7—H7114.2C17—C16—C15119.2 (4)
C2—C7—H7114.2C17—C16—H16120.4
C7—C8—C9118.8 (3)C15—C16—H16120.4
C7—C8—C12132.2 (3)C16—C17—C18120.5 (4)
C9—C8—C12108.9 (3)C16—C17—H17119.8
O1—C9—C10125.4 (3)C18—C17—H17119.8
O1—C9—C8126.7 (3)C19—C18—C17119.6 (4)
C10—C9—C8107.9 (3)C19—C18—H18120.2
C13—C10—C9121.0 (3)C17—C18—H18120.2
C13—C10—C11129.9 (3)C18—C19—C14121.5 (4)
C9—C10—C11108.8 (3)C18—C19—H19119.2
C10—C11—C12105.5 (3)C14—C19—H19119.2
C10—C11—H11A110.6
C6—C1—C2—C30.1 (5)C8—C9—C10—C1111.3 (4)
Br1—C1—C2—C3178.6 (3)C13—C10—C11—C12157.8 (4)
C6—C1—C2—C7179.1 (3)C9—C10—C11—C1216.4 (4)
Br1—C1—C2—C70.4 (5)C7—C8—C12—C11175.4 (4)
C1—C2—C3—C40.1 (6)C9—C8—C12—C118.5 (4)
C7—C2—C3—C4178.8 (4)C10—C11—C12—C815.1 (4)
C2—C3—C4—C50.4 (6)C9—C10—C13—C14178.3 (3)
C3—C4—C5—C60.5 (6)C11—C10—C13—C144.8 (7)
C4—C5—C6—C10.2 (6)C10—C13—C14—C1939.3 (6)
C2—C1—C6—C50.1 (6)C10—C13—C14—C15141.5 (4)
Br1—C1—C6—C5178.7 (3)C19—C14—C15—C160.0 (5)
C3—C2—C7—C85.1 (6)C13—C14—C15—C16179.2 (4)
C1—C2—C7—C8176.1 (4)C19—C14—C15—Br2178.0 (3)
C2—C7—C8—C9176.3 (3)C13—C14—C15—Br22.7 (5)
C2—C7—C8—C120.6 (7)C14—C15—C16—C170.7 (6)
C7—C8—C9—O14.5 (6)Br2—C15—C16—C17178.8 (3)
C12—C8—C9—O1178.8 (4)C15—C16—C17—C180.3 (7)
C7—C8—C9—C10175.2 (3)C16—C17—C18—C190.9 (7)
C12—C8—C9—C101.5 (4)C17—C18—C19—C141.6 (6)
O1—C9—C10—C1316.3 (6)C15—C14—C19—C181.2 (6)
C8—C9—C10—C13163.4 (3)C13—C14—C19—C18178.0 (4)
O1—C9—C10—C11168.9 (4)

Experimental details

Crystal data
Chemical formulaC19H14Br2O
Mr418.12
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)8.6504 (8), 8.4789 (8), 22.126 (2)
β (°) 93.119 (2)
V3)1620.5 (3)
Z4
Radiation typeMo Kα
µ (mm1)5.00
Crystal size (mm)0.33 × 0.20 × 0.19
Data collection
DiffractometerBruker APEX CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 2002)
Tmin, Tmax0.309, 0.391
No. of measured, independent and
observed [I > 2σ(I)] reflections
8202, 2857, 2292
Rint0.024
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.095, 1.04
No. of reflections2857
No. of parameters199
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.69, 0.96

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2002), SHELXL97.

 

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