organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 70| Part 5| May 2014| Pages o593-o594

(E)-3-(4-Hy­dr­oxy-3-meth­­oxy­phen­yl)-1-(4-hy­dr­oxy­phen­yl)prop-2-en-1-one

aPG and Research Department of Physics, Queen Mary's College, Chennai-4, Tamilnadu, India, and bPG and Research Department of Chemistry, Presidency College, Chennai-5, Tamil Nadu, India
*Correspondence e-mail: guqmc@yahoo.com

(Received 13 March 2014; accepted 17 April 2014; online 26 April 2014)

In the title compound, C16H14O4, there is an intra­molecular O—H⋯O hydrogen bond. The benzene rings are inclined to one another by 13.89 (9)°. The prop-2-en-1-one group is twisted slightly, the O=C—Car—Car (ar = aromatic) and C=C—C=O torsion angles being −10.4 (3) and −7.4 (3)°, respectively. In the crystal, mol­ecules are linked by O—H⋯O hydrogen bonds, forming chains along [100]. These chains are further linked by O—H⋯O hydrogen bonds, forming corrugated sheets lying parallel to (010). There are C—H⋯π inter­actions present within the sheets.

Related literature

For the biological activity of chalcones and chalcone derivatives, see: Marais et al. (2005[Marais, J. P. J., Ferreira, D. & Slade, D. (2005). Phytochemistry, 66, 2145-2176.]); Di Carlo et al. (1999[Di Carlo, G., Mascolo, N., Izzo, A. A. & Capasso, F. (1999). Life Sci. 65, 337-353.]); Troeberg et al. (2000[Troeberg, L., Chen, X., Flaherty, T. M., Morty, R. E., Cheng, M., Springer, H. C., McKerrow, J. H., Kenyon, G. L., Lonsdale-Eccles, J. D., Coetzer, T. H. T. & Cohen, F. E. (2000). Mol. Med. 6, 660-669.]); Ni et al. (2004[Ni, L., Meng, C. Q. & Sikorski, J. A. (2004). Exp. Opin. Ther. Pat. 14, 1669-1691.]). For a related structure, see: Jasinski et al. (2011[Jasinski, J. P., Butcher, R. J., Musthafa Khaleel, V., Sarojini, B. K. & Narayana, B. (2011). Acta Cryst. E67, o813.]). For the synthesis, see: Sidharthan et al. (2012[Sidharthan, J., Jonathan, D. R. & Amaladhas, T. P. (2012). Int. J. Chem. Appl. 4, 241-250.]); Chitra et al. (2013[Chitra, M., Jonathan, D. R., Rajan, Y. C. & Duraipandiyan, V. (2013). Int. J. Chem. Appl. 5, 73-81.]). For standard bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C16H14O4

  • Mr = 270.27

  • Orthorhombic, P b c a

  • a = 16.2808 (8) Å

  • b = 10.4348 (5) Å

  • c = 16.2905 (7) Å

  • V = 2767.5 (2) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 293 K

  • 0.35 × 0.30 × 0.25 mm

Data collection
  • Bruker Kappa APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2004[Bruker (2004). APEX2, SAINT, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.968, Tmax = 0.977

  • 12921 measured reflections

  • 3441 independent reflections

  • 1935 reflections with I > 2σ(I)

  • Rint = 0.027

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.128

  • S = 1.05

  • 3344 reflections

  • 189 parameters

  • 2 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.18 e Å−3

  • Δρmin = −0.20 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg is the centroid of the C1–C6 benzene ring.

D—H⋯A D—H H⋯A DA D—H⋯A
O4—H4O⋯O3 0.86 (2) 2.20 (3) 2.655 (2) 113 (2)
O2—H2O⋯O1i 0.87 (2) 1.87 (2) 2.7349 (18) 173 (2)
O4—H4O⋯O1ii 0.86 (2) 2.22 (2) 2.937 (2) 141 (3)
C16—H16ACgii 0.96 2.86 3.747 (3) 155
Symmetry codes: (i) [x+{\script{1\over 2}}, y, -z+{\script{1\over 2}}]; (ii) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2, SAINT, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: APEX2 and SAINT (Bruker, 2004[Bruker (2004). APEX2, SAINT, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT and XPREP (Bruker, 2004[Bruker (2004). APEX2, SAINT, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to solve structure: SIR92 (Altomare et al., 1993[Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343-350.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Chalcones are known as the precursors of all flavonoid type natural products in biosynthesis (Marais et al., 2005). They are a major class of natural products with widespread distribution in fruits, vegetables, spices, tea and soy based food stuff and have been the subjects of interest for their significant pharmacological activities (Di Carlo et al., 1999). Many chalcones have been described for their high anti-malarial activity, probably as a result of addition of nucleophilic species to the double bond of the enone (Troeberg et al., 2000). A review of anti-infective and anti-inflammatory chalcones and recent advances in therapeutic chalcones have been reported (Ni et al., 2004). To understand the three dimensional features of this class of compounds, we report herein on the crystal structure of the title compound.

The molecular structure of the title molecule is illustrated in Fig. 1. The bond lengths (Allen et al., 1987) and bond angles are within normal values. The bond angles C6—C7—C8 = 119.12 (14) ° and C8C9—C10 = 127.20 (17) ° are comparable with those in a similar reported structure (E)-3-(3,4-Dimethoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (2E)-3-(3,4-Dimethoxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (Jasinski et al., 2011). This may be due to the presence of the keto group and associated steric forces. The prop-2-en-1-one group is twisted slightly with torsion angles O1C7—C8—C9 and C5—C6—C7O1 being -10.4 (3) and -7.4 (3) °, respectively. These values are comparable with the value of -6.9 (2) and -15.9 (2) ° reported for the above mentioned structure.

In the crystal, molecules are linked by O—H···O hydrogen bonds forming chains propagating along the a axis (Table 1 and Fig. 2). These chains are linked by further O—H···O hydrogen bonds forming corrugated sheets lying parallel to (010). Within the sheets there are C—H···π interactions present (Table 1). In total each molecule is linked to four neighbours by O—H···O hydrogen bonds (Table 1 and Fig. 2). Atom O4 acts as a bifurcated donor forming intra- and inter-molecular O—H···O hydrogen bonds (Table 1 and Fig. 2).

Related literature top

For the biological activity of chalcones and chalcone derivatives, see: Marais et al. (2005); Di Carlo et al. (1999); Troeberg et al. (2000); Ni et al. (2004). For a related structure, see: Jasinski et al. (2011). For the synthesis, see: Sidharthan et al. (2012); Chitra et al. (2013). For standard bond lengths, see: Allen et al. (1987).

Experimental top

The title compound was synthesized by a published procedure using the acid catalyzed Claisen-Schmidt reaction (Sidharthan et al., 2012; Chitra et al., 2013) Dry HCl gas was passed through a well cooled and stirred solution of 4-hydroxyacetophenone (0.02 mol) and vanillin (0.02 mol) in 125 ml of dry ethanol, placed in a 250 ml round-bottomed flask, for about 1 h. A wine-red coloured solution was formed to which ice cold water was added. Yellow block-like crystals of the title compound separated and were washed with double distilled water and re-crystallized from hot ethanol (Yield 85%; M.p. 454 K).

Refinement top

The OH H atoms were located from difference Fourier maps and refined with Uiso(H)= 1.5Ueq(O). The C-bound H atoms were positioned geometrically and treated as riding atoms: C—H distance of 0.93 - 0.96 Å with Uiso(H)= 1.5Ueq(C-methyl) and = 1.2Ueq(C) for other H atom.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. A view along the x axis of the crystal packing of the title compound. Hydrogen bonds are shown as dashed lines (see Table 1 for details).
(E)-3-(4-Hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one top
Crystal data top
C16H14O4F(000) = 1136
Mr = 270.27Dx = 1.297 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 3441 reflections
a = 16.2808 (8) Åθ = 2.5–28.3°
b = 10.4348 (5) ŵ = 0.09 mm1
c = 16.2905 (7) ÅT = 293 K
V = 2767.5 (2) Å3Block, yellow
Z = 80.35 × 0.30 × 0.25 mm
Data collection top
Bruker Kappa APEXII CCD
diffractometer
3441 independent reflections
Radiation source: fine-focus sealed tube1935 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.027
ω and ϕ scanθmax = 28.3°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
h = 2117
Tmin = 0.968, Tmax = 0.977k = 137
12921 measured reflectionsl = 2121
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)] = 0.039H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.128 w = 1/[σ2(Fo2) + (0.0473P)2 + 0.8783P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max = 0.004
3344 reflectionsΔρmax = 0.18 e Å3
189 parametersΔρmin = 0.20 e Å3
2 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0024 (6)
Crystal data top
C16H14O4V = 2767.5 (2) Å3
Mr = 270.27Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 16.2808 (8) ŵ = 0.09 mm1
b = 10.4348 (5) ÅT = 293 K
c = 16.2905 (7) Å0.35 × 0.30 × 0.25 mm
Data collection top
Bruker Kappa APEXII CCD
diffractometer
3441 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
1935 reflections with I > 2σ(I)
Tmin = 0.968, Tmax = 0.977Rint = 0.027
12921 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0392 restraints
wR(F2) = 0.128H atoms treated by a mixture of independent and constrained refinement
S = 1.05Δρmax = 0.18 e Å3
3344 reflectionsΔρmin = 0.20 e Å3
189 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
O10.21682 (7)0.58070 (13)0.26522 (8)0.0532 (4)
O20.59318 (7)0.69018 (13)0.32421 (9)0.0594 (4)
H2O0.6310 (12)0.649 (2)0.2968 (14)0.089*
O30.28796 (9)0.08570 (16)0.06956 (10)0.0762 (5)
O40.13699 (9)0.00902 (16)0.07979 (10)0.0708 (5)
H4O0.1798 (13)0.024 (3)0.1090 (16)0.106*
C10.43059 (10)0.50808 (17)0.22500 (11)0.0431 (4)
H10.42450.43970.18890.052*
C20.50835 (10)0.54733 (17)0.24660 (11)0.0445 (4)
H20.55410.50650.22460.053*
C30.51802 (10)0.64693 (17)0.30075 (11)0.0423 (4)
C40.44972 (11)0.70803 (18)0.33262 (12)0.0511 (5)
H40.45620.77590.36900.061*
C50.37224 (10)0.66855 (17)0.31058 (11)0.0461 (4)
H50.32670.70970.33270.055*
C60.36105 (9)0.56830 (15)0.25593 (10)0.0366 (4)
C70.27741 (10)0.53112 (17)0.23093 (10)0.0400 (4)
C80.26703 (10)0.43695 (18)0.16605 (11)0.0453 (4)
H80.31330.41320.13620.054*
C90.19621 (11)0.38287 (17)0.14669 (11)0.0459 (4)
H90.15040.41110.17550.055*
C100.18214 (10)0.28457 (17)0.08558 (11)0.0444 (4)
C110.10435 (11)0.2317 (2)0.07729 (12)0.0523 (5)
H110.06130.26250.10920.063*
C120.09021 (12)0.1337 (2)0.02206 (12)0.0570 (5)
H120.03780.09900.01740.068*
C130.15256 (12)0.08717 (19)0.02586 (11)0.0505 (5)
C140.23128 (11)0.13987 (18)0.01877 (12)0.0496 (5)
C150.24529 (11)0.23674 (18)0.03604 (11)0.0494 (5)
H150.29770.27140.04050.059*
C160.37141 (14)0.1250 (3)0.0603 (2)0.1069 (11)
H16A0.40610.07190.09370.160*
H16B0.38730.11690.00380.160*
H16C0.37700.21280.07720.160*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0284 (7)0.0681 (9)0.0632 (8)0.0049 (6)0.0022 (5)0.0101 (7)
O20.0294 (7)0.0634 (9)0.0855 (10)0.0054 (6)0.0028 (6)0.0207 (8)
O30.0523 (9)0.0907 (12)0.0856 (11)0.0047 (8)0.0006 (8)0.0401 (9)
O40.0661 (10)0.0756 (10)0.0707 (10)0.0206 (8)0.0097 (7)0.0194 (8)
C10.0338 (9)0.0456 (10)0.0500 (10)0.0044 (7)0.0024 (7)0.0103 (8)
C20.0275 (9)0.0510 (10)0.0550 (10)0.0064 (7)0.0007 (7)0.0087 (9)
C30.0290 (9)0.0447 (10)0.0530 (10)0.0026 (7)0.0014 (7)0.0011 (8)
C40.0373 (10)0.0531 (11)0.0629 (12)0.0020 (8)0.0042 (8)0.0216 (9)
C50.0310 (9)0.0517 (10)0.0555 (11)0.0030 (8)0.0083 (7)0.0108 (9)
C60.0287 (8)0.0403 (9)0.0407 (9)0.0004 (7)0.0005 (6)0.0004 (8)
C70.0303 (9)0.0444 (9)0.0452 (9)0.0018 (7)0.0005 (7)0.0033 (8)
C80.0307 (9)0.0561 (11)0.0491 (10)0.0000 (8)0.0005 (7)0.0049 (9)
C90.0342 (10)0.0514 (10)0.0520 (10)0.0002 (8)0.0001 (8)0.0006 (9)
C100.0347 (9)0.0494 (10)0.0490 (10)0.0053 (8)0.0055 (8)0.0043 (8)
C110.0390 (10)0.0655 (12)0.0524 (11)0.0099 (9)0.0016 (8)0.0033 (10)
C120.0441 (11)0.0695 (13)0.0575 (12)0.0221 (10)0.0100 (9)0.0057 (10)
C130.0516 (12)0.0526 (11)0.0475 (10)0.0106 (9)0.0139 (9)0.0030 (9)
C140.0426 (11)0.0545 (11)0.0518 (10)0.0028 (9)0.0076 (8)0.0008 (9)
C150.0361 (9)0.0552 (11)0.0568 (11)0.0071 (8)0.0065 (8)0.0035 (9)
C160.0457 (14)0.139 (3)0.136 (3)0.0060 (15)0.0096 (14)0.076 (2)
Geometric parameters (Å, º) top
O1—C71.2461 (19)C7—C81.453 (2)
O2—C31.359 (2)C8—C91.322 (2)
O2—H2O0.871 (16)C8—H80.9300
O3—C141.362 (2)C9—C101.448 (2)
O3—C161.427 (3)C9—H90.9300
O4—C131.358 (2)C10—C111.388 (2)
O4—H4O0.857 (17)C10—C151.399 (2)
C1—C21.376 (2)C11—C121.381 (3)
C1—C61.389 (2)C11—H110.9300
C1—H10.9300C12—C131.370 (3)
C2—C31.372 (2)C12—H120.9300
C2—H20.9300C13—C141.399 (2)
C3—C41.383 (2)C14—C151.368 (3)
C4—C51.375 (2)C15—H150.9300
C4—H40.9300C16—H16A0.9600
C5—C61.386 (2)C16—H16B0.9600
C5—H50.9300C16—H16C0.9600
C6—C71.473 (2)
C3—O2—H2O109.3 (16)C8—C9—C10127.20 (17)
C14—O3—C16117.46 (16)C8—C9—H9116.4
C13—O4—H4O110 (2)C10—C9—H9116.4
C2—C1—C6121.48 (16)C11—C10—C15118.20 (17)
C2—C1—H1119.3C11—C10—C9119.54 (17)
C6—C1—H1119.3C15—C10—C9122.21 (15)
C3—C2—C1119.68 (16)C12—C11—C10120.65 (18)
C3—C2—H2120.2C12—C11—H11119.7
C1—C2—H2120.2C10—C11—H11119.7
O2—C3—C2122.38 (15)C13—C12—C11120.68 (17)
O2—C3—C4117.73 (16)C13—C12—H12119.7
C2—C3—C4119.88 (15)C11—C12—H12119.7
C5—C4—C3120.11 (17)O4—C13—C12119.51 (17)
C5—C4—H4119.9O4—C13—C14120.99 (19)
C3—C4—H4119.9C12—C13—C14119.50 (18)
C4—C5—C6120.98 (16)O3—C14—C15126.17 (17)
C4—C5—H5119.5O3—C14—C13114.04 (17)
C6—C5—H5119.5C15—C14—C13119.79 (18)
C5—C6—C1117.86 (15)C14—C15—C10121.17 (17)
C5—C6—C7119.86 (15)C14—C15—H15119.4
C1—C6—C7122.26 (15)C10—C15—H15119.4
O1—C7—C8120.98 (15)O3—C16—H16A109.5
O1—C7—C6119.90 (15)O3—C16—H16B109.5
C8—C7—C6119.12 (14)H16A—C16—H16B109.5
C9—C8—C7124.31 (16)O3—C16—H16C109.5
C9—C8—H8117.8H16A—C16—H16C109.5
C7—C8—H8117.8H16B—C16—H16C109.5
C6—C1—C2—C30.9 (3)C8—C9—C10—C11175.35 (19)
C1—C2—C3—O2179.82 (17)C8—C9—C10—C152.2 (3)
C1—C2—C3—C40.7 (3)C15—C10—C11—C120.6 (3)
O2—C3—C4—C5179.66 (17)C9—C10—C11—C12177.03 (17)
C2—C3—C4—C50.5 (3)C10—C11—C12—C130.3 (3)
C3—C4—C5—C60.5 (3)C11—C12—C13—O4179.87 (18)
C4—C5—C6—C10.8 (3)C11—C12—C13—C140.2 (3)
C4—C5—C6—C7177.68 (17)C16—O3—C14—C155.9 (3)
C2—C1—C6—C51.0 (3)C16—O3—C14—C13173.8 (2)
C2—C1—C6—C7177.44 (16)O4—C13—C14—O30.3 (3)
C5—C6—C7—O17.4 (3)C12—C13—C14—O3179.98 (18)
C1—C6—C7—O1174.18 (16)O4—C13—C14—C15179.99 (17)
C5—C6—C7—C8172.36 (16)C12—C13—C14—C150.3 (3)
C1—C6—C7—C86.0 (2)O3—C14—C15—C10179.67 (18)
O1—C7—C8—C910.4 (3)C13—C14—C15—C100.0 (3)
C6—C7—C8—C9169.82 (17)C11—C10—C15—C140.5 (3)
C7—C8—C9—C10176.97 (17)C9—C10—C15—C14177.08 (17)
Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the C1–C6 benzene ring.
D—H···AD—HH···AD···AD—H···A
O4—H4O···O30.86 (2)2.20 (3)2.655 (2)113 (2)
O2—H2O···O1i0.87 (2)1.87 (2)2.7349 (18)173 (2)
O4—H4O···O1ii0.86 (2)2.22 (2)2.937 (2)141 (3)
C16—H16A···Cgii0.962.863.747 (3)155
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) x, y+1/2, z1/2.
Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the C1–C6 benzene ring.
D—H···AD—HH···AD···AD—H···A
O4—H4O···O30.857 (17)2.20 (3)2.655 (2)113 (2)
O2—H2O···O1i0.871 (16)1.868 (16)2.7349 (18)173 (2)
O4—H4O···O1ii0.857 (17)2.22 (2)2.937 (2)141 (3)
C16—H16A···Cgii0.962.863.747 (3)155
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) x, y+1/2, z1/2.
 

Acknowledgements

The authors thank Professor D. Velmurugan, Centre for Advanced Study in Crystallography and Biophysics, University of Madras, for providing data-collection and computer facilities.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science Google Scholar
First citationAltomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343–350.  CrossRef Web of Science IUCr Journals Google Scholar
First citationBruker (2004). APEX2, SAINT, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationChitra, M., Jonathan, D. R., Rajan, Y. C. & Duraipandiyan, V. (2013). Int. J. Chem. Appl. 5, 73–81.  Google Scholar
First citationDi Carlo, G., Mascolo, N., Izzo, A. A. & Capasso, F. (1999). Life Sci. 65, 337–353.  Web of Science CrossRef PubMed CAS Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationJasinski, J. P., Butcher, R. J., Musthafa Khaleel, V., Sarojini, B. K. & Narayana, B. (2011). Acta Cryst. E67, o813.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationMarais, J. P. J., Ferreira, D. & Slade, D. (2005). Phytochemistry, 66, 2145–2176.  Web of Science CrossRef PubMed CAS Google Scholar
First citationNi, L., Meng, C. Q. & Sikorski, J. A. (2004). Exp. Opin. Ther. Pat. 14, 1669–1691.  Web of Science CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSidharthan, J., Jonathan, D. R. & Amaladhas, T. P. (2012). Int. J. Chem. Appl. 4, 241–250.  Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationTroeberg, L., Chen, X., Flaherty, T. M., Morty, R. E., Cheng, M., Springer, H. C., McKerrow, J. H., Kenyon, G. L., Lonsdale-Eccles, J. D., Coetzer, T. H. T. & Cohen, F. E. (2000). Mol. Med. 6, 660–669.  Web of Science PubMed CAS Google Scholar

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Volume 70| Part 5| May 2014| Pages o593-o594
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