PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2009 June 1; 65(Pt 6): o1301–o1302.
Published online 2009 May 14. doi:  10.1107/S1600536809017577
PMCID: PMC2969631

(E)-3-[4-(Hex­yloxy)phen­yl]-1-(2-hydroxy­phen­yl)prop-2-en-1-one

Abstract

In the title compound, C21H24O3, the conformation of the enone group is scis. The benzene rings are inclined at an angle of 7.9 (1)°. The alk­oxy tail is planar, with a maximum deviation from the least-squares plane of 0.009 (2) Å, and adopts a trans conformation throughout. An intra­molecular O—H(...)O inter­action between the keto and hydr­oxy groups forms S(6) ring motifs. In the crystal, mol­ecules are arranged in a head-to-tail manner down the a axis and are subsequently stacked along the b axis, forming mol­ecular sheets parallel to the ab plane. The crystal structure is further stabilized by weak C—H(...)π inter­actions and short C(...)O [3.376 (2) Å] contacts.

Related literature

For the biological properties of chalcone derivatives, see: Bhat et al. (2005 [triangle]); Xue et al. (2004 [triangle]); Zhao et al. (2005 [triangle]); Lee et al. (2006 [triangle]). For related structures, see: Razak, Fun, Ngaini, Rahman & Hussain (2009 [triangle]); Razak, Fun, Ngaini, Fadzillah & Hussain (2009a [triangle],b [triangle]); Ngaini, Fadzillah et al. (2009 [triangle]); Ngaini, Rahman et al. (2009 [triangle]). For details of hydrogen-bond motifs, see: Bernstein et al. (1995 [triangle]). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o1301-scheme1.jpg

Experimental

Crystal data

  • C21H24O3
  • M r = 324.40
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o1301-efi1.jpg
  • a = 19.6443 (5) Å
  • b = 7.1966 (2) Å
  • c = 12.6520 (3) Å
  • β = 106.438 (2)°
  • V = 1715.53 (8) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 100 K
  • 0.47 × 0.12 × 0.04 mm

Data collection

  • Bruker SMART APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2005 [triangle]) T min = 0.962, T max = 0.997
  • 20873 measured reflections
  • 5025 independent reflections
  • 2783 reflections with I > 2σ(I)
  • R int = 0.057

Refinement

  • R[F 2 > 2σ(F 2)] = 0.070
  • wR(F 2) = 0.190
  • S = 1.05
  • 5025 reflections
  • 222 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.53 e Å−3
  • Δρmin = −0.29 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT (Bruker, 2005 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809017577/sj2623sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809017577/sj2623Isup2.hkl

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

Acknowledgments

HKF and IAR thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312 and for the Research University Golden Goose grant No.1001/PFIZIK/811012. ZN and HH thank Universiti Malaysia Sarawak for the Geran Penyelidikan Dana Khas Inovasi, grant No. DI/01/2007(01). SMHF thanks the Malaysian Government and Universiti Malaysia Sarawak for providing a scholarship for postgraduate studies.

supplementary crystallographic information

Comment

The biological properties of chalcones derivatives, such as their anticancer (Bhat et al., 2005), antimalarial (Xue et al., 2004), antiangiogenic and antitumour (Lee et al., 2006) and antiplatelet (Zhao et al., 2005) activities, have been extensively reported. Synthetic and naturally occurring chalcones are of interest and have been widely studied and developed as one of the pharmaceutically important molecules. As part of our studies, we have synthesized the title chalcone derivative, (I). Its antibacterial activity was tested against E. coli ATCC 8739 and the compound demonstrated antimicrobial activity. In this paper, we report the crystal structure of the title compound.

The bond lengths observed in the title compound (Fig.1) are comparable with those reported by Allen et al. (1987). The enone (O2/C7—C9) moiety adopts s-cis conformation with a O2—C7—C8—C9 torsion angle of -3.6 (3)°. The mean plane through the enone moiety makes dihedral angles of 0.89 (1)° and 7.9 (1)° with the C1—C6 and C10—C15 benzene rings, respectively. The dihedral angle between the two benzene rings is 7.9 (1)°.

The slight opening of the C1—C6—C7 (123.4 (2)°) and C6—C7—C8 (121.1 (2)°) angles is the result of the short H1A···H8A (2.15 Å) contact whereas close interatomic contact between H8A and H15A (2.36 Å) widened the C8—C9—C10 and C9—C10—C15 angles to 129.2 (2)° and 124.1 (2)°, respectively. Likewise, strain induced by short H12A···H16A (2.39 Å) and H12A···H16B (2.33 Å) contacts resulted in the opening of the O3—C13—C12 (125.1 (2)°) angle. Similar features were also reported in related structures (Razak, Fun, Ngaini, Rahman et al., 2009; Razak, Fun, Ngaini, Fadzillah & Hussain, 2009a,b; Ngaini, Fadzillah et al., 2009; Ngaini, Rahman et al., 2009).

The zigzag alkoxyl tail adopts an all-trans conformation with the largest deviation from the ideal value being -179.3 (2)° for C17—C18—C19—C20 torsion angle. The alkoxyl chain is planar with the maximum deviation from the least-squares plane of 0.009 (2)Å at C18. The zigzag plane makes a dihedral angle of 2.2 (1)° with the attached benzene ring.

The keto and hydroxy groups in the molecule form an intramolecular O1—H1O1···O2 interaction (Table 1) generating a ring of graph-set motif S(6) (Bernstein et al., 1995). In the crystal structure, the molecules are arranged into a head-to-tail manner down the a axis (Fig. 2). Molecules are subsequently stacked along the b axis, forming molecular sheets parallel to the ab plane. In the absence of conventional hydrogen bonds, the crystal packing is strengthened by the presence of weak C—H···π interactions between atom C20 of the alkoxyl tail and the C1—C6 benzene ring (Table 1). There is also a short C···O (x, 1.5-y, 0.5+z ) [3.376 (2)Å] contact.

Experimental

A mixture of 2-hydroxyacetophenone (2.72 ml, 20 mmol) and 4-hexyloxybenzaldehyde (4.12 ml, 20 mmol) and KOH (4.04 g, 72 mmol) in 60 ml of methanol was heated at reflux for 24 h. The reaction was cooled to room temperature and acidified with cold diluted HCl (2 M). The resulting precipitate was filtered, washed and dried. After redissolving in hexane, followed by few days of slow evaporation, crystals were collected.

Refinement

The O-bound H atom was located in a difference Fourier map and refined freely. All the C-bound H atoms were positioned geometrically and refined using a riding model with C—H = 0.93–0.97 Å. The Uiso values were constrained to be -1.5Uequ (methyl H atoms) and -1.2Uequ (other H atoms). The rotating model group was applied for the methyl group.

Figures

Fig. 1.
The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme. The intramolecular interaction is shown as dashed line.
Fig. 2.
The crystal packing of the title compound, viewed down the c axis.

Crystal data

C21H24O3F(000) = 696
Mr = 324.40Dx = 1.256 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3217 reflections
a = 19.6443 (5) Åθ = 3.0–30.0°
b = 7.1966 (2) ŵ = 0.08 mm1
c = 12.6520 (3) ÅT = 100 K
β = 106.438 (2)°Needle, yellow
V = 1715.53 (8) Å30.47 × 0.12 × 0.04 mm
Z = 4

Data collection

Bruker SMART APEXII CCD area-detector diffractometer5025 independent reflections
Radiation source: sealed tube2783 reflections with I > 2σ(I)
graphiteRint = 0.057
[var phi] and ω scansθmax = 30.1°, θmin = 1.1°
Absorption correction: multi-scan (SADABS; Bruker, 2005)h = −27→27
Tmin = 0.962, Tmax = 0.997k = −9→10
20873 measured reflectionsl = −17→17

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)] = 0.070Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.190H atoms treated by a mixture of independent and constrained refinement
S = 1.05w = 1/[σ2(Fo2) + (0.0907P)2] where P = (Fo2 + 2Fc2)/3
5025 reflections(Δ/σ)max < 0.001
222 parametersΔρmax = 0.53 e Å3
0 restraintsΔρmin = −0.29 e Å3

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
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
O10.31582 (7)0.61343 (19)−0.09249 (11)0.0210 (3)
O20.20488 (6)0.60487 (18)−0.03200 (11)0.0203 (3)
O3−0.06969 (6)0.61140 (17)0.36275 (11)0.0168 (3)
C10.35907 (9)0.6404 (2)0.20871 (16)0.0159 (4)
H1A0.33710.64620.26480.019*
C20.43212 (9)0.6445 (3)0.23554 (17)0.0202 (4)
H2A0.45900.65120.30890.024*
C30.46535 (9)0.6386 (3)0.15149 (16)0.0194 (4)
H3A0.51460.64150.16910.023*
C40.42582 (9)0.6283 (3)0.04267 (16)0.0175 (4)
H4A0.44850.6249−0.01260.021*
C50.35182 (9)0.6230 (2)0.01518 (15)0.0149 (4)
C60.31698 (9)0.6276 (2)0.09933 (15)0.0137 (4)
C70.23827 (9)0.6181 (2)0.06736 (15)0.0138 (4)
C80.19935 (9)0.6221 (2)0.15096 (16)0.0146 (4)
H8A0.22360.62500.22560.018*
C90.12783 (9)0.6216 (2)0.11734 (16)0.0153 (4)
H9A0.10760.62150.04140.018*
C100.07792 (8)0.6213 (2)0.18274 (15)0.0130 (4)
C110.00511 (9)0.6329 (2)0.12710 (16)0.0154 (4)
H11A−0.00910.64380.05070.018*
C12−0.04606 (9)0.6284 (3)0.18360 (16)0.0160 (4)
H12A−0.09400.63440.14540.019*
C13−0.02488 (9)0.6148 (2)0.29733 (16)0.0135 (4)
C140.04731 (9)0.6028 (2)0.35469 (16)0.0156 (4)
H14A0.06120.59250.43110.019*
C150.09760 (9)0.6064 (2)0.29794 (16)0.0154 (4)
H15A0.14540.59880.33660.019*
C16−0.14479 (8)0.6211 (3)0.31008 (15)0.0153 (4)
H16A−0.16020.51480.26210.018*
H16B−0.15650.73350.26640.018*
C17−0.18025 (9)0.6212 (3)0.40186 (15)0.0151 (4)
H17A−0.16310.72690.44960.018*
H17B−0.16670.50940.44550.018*
C18−0.26094 (9)0.6306 (3)0.36018 (15)0.0149 (4)
H18A−0.27850.52550.31220.018*
H18B−0.27500.74340.31760.018*
C19−0.29383 (9)0.6284 (3)0.45638 (15)0.0144 (4)
H19A−0.27850.51660.49940.017*
H19B−0.27590.73410.50370.017*
C20−0.37459 (9)0.6351 (3)0.42130 (16)0.0162 (4)
H20A−0.39310.52900.37470.019*
H20B−0.39040.74690.37860.019*
C21−0.40379 (9)0.6331 (3)0.52132 (17)0.0219 (5)
H21A−0.45470.63850.49690.033*
H21B−0.38590.73860.56720.033*
H21C−0.38920.52100.56260.033*
H1O10.2698 (14)0.605 (3)−0.094 (2)0.059 (9)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0199 (7)0.0333 (9)0.0108 (7)−0.0030 (6)0.0060 (6)0.0011 (6)
O20.0166 (6)0.0309 (8)0.0131 (7)0.0007 (6)0.0035 (6)0.0021 (6)
O30.0115 (6)0.0264 (8)0.0139 (7)0.0003 (5)0.0060 (5)−0.0003 (6)
C10.0167 (8)0.0195 (10)0.0137 (10)0.0012 (8)0.0078 (7)0.0006 (8)
C20.0174 (9)0.0295 (12)0.0132 (10)−0.0017 (8)0.0035 (8)0.0002 (9)
C30.0142 (8)0.0238 (11)0.0213 (11)−0.0006 (8)0.0068 (8)0.0018 (9)
C40.0179 (8)0.0193 (10)0.0198 (11)0.0006 (8)0.0125 (8)0.0021 (9)
C50.0203 (9)0.0132 (10)0.0127 (10)−0.0009 (7)0.0071 (8)0.0018 (8)
C60.0149 (8)0.0130 (10)0.0146 (10)0.0012 (7)0.0068 (7)0.0004 (8)
C70.0154 (8)0.0125 (9)0.0147 (10)0.0010 (7)0.0061 (7)0.0016 (8)
C80.0149 (8)0.0162 (10)0.0135 (10)0.0005 (7)0.0055 (7)0.0018 (8)
C90.0164 (8)0.0146 (10)0.0157 (10)0.0012 (7)0.0061 (7)0.0005 (8)
C100.0122 (8)0.0126 (9)0.0149 (10)−0.0001 (7)0.0049 (7)−0.0004 (8)
C110.0162 (8)0.0180 (10)0.0119 (10)0.0012 (7)0.0041 (7)0.0008 (8)
C120.0120 (8)0.0196 (10)0.0168 (10)0.0023 (7)0.0046 (7)0.0017 (9)
C130.0135 (8)0.0132 (9)0.0152 (10)0.0000 (7)0.0062 (7)−0.0021 (8)
C140.0152 (8)0.0202 (11)0.0111 (10)−0.0004 (7)0.0031 (7)0.0007 (8)
C150.0115 (8)0.0173 (10)0.0170 (10)−0.0010 (7)0.0033 (7)−0.0027 (8)
C160.0102 (7)0.0197 (10)0.0156 (10)0.0000 (7)0.0030 (7)−0.0002 (8)
C170.0145 (8)0.0177 (10)0.0142 (10)0.0016 (7)0.0061 (7)0.0004 (8)
C180.0148 (8)0.0167 (10)0.0153 (10)−0.0005 (7)0.0076 (7)−0.0008 (8)
C190.0148 (8)0.0158 (10)0.0138 (10)0.0000 (7)0.0060 (7)0.0003 (8)
C200.0150 (8)0.0172 (10)0.0175 (10)−0.0002 (7)0.0065 (7)0.0011 (8)
C210.0176 (9)0.0283 (12)0.0231 (12)0.0018 (8)0.0112 (8)0.0040 (10)

Geometric parameters (Å, °)

O1—C51.347 (2)C12—C131.384 (3)
O1—H1O10.90 (3)C12—H12A0.9300
O2—C71.246 (2)C13—C141.401 (2)
O3—C131.369 (2)C14—C151.376 (2)
O3—C161.438 (2)C14—H14A0.9300
C1—C21.378 (2)C15—H15A0.9300
C1—C61.400 (3)C16—C171.514 (2)
C1—H1A0.9300C16—H16A0.9700
C2—C31.397 (3)C16—H16B0.9700
C2—H2A0.9300C17—C181.524 (2)
C3—C41.378 (3)C17—H17A0.9700
C3—H3A0.9300C17—H17B0.9700
C4—C51.396 (2)C18—C191.531 (2)
C4—H4A0.9300C18—H18A0.9700
C5—C61.420 (2)C18—H18B0.9700
C6—C71.485 (2)C19—C201.522 (2)
C7—C81.470 (2)C19—H19A0.9700
C8—C91.348 (2)C19—H19B0.9700
C8—H8A0.9300C20—C211.530 (3)
C9—C101.451 (2)C20—H20A0.9700
C9—H9A0.9300C20—H20B0.9700
C10—C151.402 (3)C21—H21A0.9600
C10—C111.406 (2)C21—H21B0.9600
C11—C121.389 (2)C21—H21C0.9600
C11—H11A0.9300
C5—O1—H1O1105.5 (18)C15—C14—H14A120.0
C13—O3—C16118.03 (14)C13—C14—H14A120.0
C2—C1—C6121.83 (17)C14—C15—C10121.08 (16)
C2—C1—H1A119.1C14—C15—H15A119.5
C6—C1—H1A119.1C10—C15—H15A119.5
C1—C2—C3119.35 (19)O3—C16—C17106.20 (15)
C1—C2—H2A120.3O3—C16—H16A110.5
C3—C2—H2A120.3C17—C16—H16A110.5
C4—C3—C2120.63 (17)O3—C16—H16B110.5
C4—C3—H3A119.7C17—C16—H16B110.5
C2—C3—H3A119.7H16A—C16—H16B108.7
C3—C4—C5120.20 (17)C16—C17—C18113.20 (15)
C3—C4—H4A119.9C16—C17—H17A108.9
C5—C4—H4A119.9C18—C17—H17A108.9
O1—C5—C4117.70 (16)C16—C17—H17B108.9
O1—C5—C6122.21 (16)C18—C17—H17B108.9
C4—C5—C6120.09 (17)H17A—C17—H17B107.8
C1—C6—C5117.89 (15)C17—C18—C19110.86 (15)
C1—C6—C7123.40 (16)C17—C18—H18A109.5
C5—C6—C7118.71 (17)C19—C18—H18A109.5
O2—C7—C8119.66 (16)C17—C18—H18B109.5
O2—C7—C6119.24 (15)C19—C18—H18B109.5
C8—C7—C6121.09 (17)H18A—C18—H18B108.1
C9—C8—C7118.73 (18)C20—C19—C18114.03 (15)
C9—C8—H8A120.6C20—C19—H19A108.7
C7—C8—H8A120.6C18—C19—H19A108.7
C8—C9—C10129.22 (19)C20—C19—H19B108.7
C8—C9—H9A115.4C18—C19—H19B108.7
C10—C9—H9A115.4H19A—C19—H19B107.6
C15—C10—C11117.84 (15)C19—C20—C21111.23 (16)
C15—C10—C9124.12 (16)C19—C20—H20A109.4
C11—C10—C9118.03 (17)C21—C20—H20A109.4
C12—C11—C10121.51 (17)C19—C20—H20B109.4
C12—C11—H11A119.2C21—C20—H20B109.4
C10—C11—H11A119.2H20A—C20—H20B108.0
C13—C12—C11119.23 (16)C20—C21—H21A109.5
C13—C12—H12A120.4C20—C21—H21B109.5
C11—C12—H12A120.4H21A—C21—H21B109.5
O3—C13—C12125.07 (15)C20—C21—H21C109.5
O3—C13—C14114.56 (16)H21A—C21—H21C109.5
C12—C13—C14120.37 (16)H21B—C21—H21C109.5
C15—C14—C13119.97 (17)
C6—C1—C2—C30.9 (3)C8—C9—C10—C11175.97 (18)
C1—C2—C3—C4−0.1 (3)C15—C10—C11—C12−0.5 (3)
C2—C3—C4—C5−0.2 (3)C9—C10—C11—C12178.26 (17)
C3—C4—C5—O1179.86 (18)C10—C11—C12—C130.9 (3)
C3—C4—C5—C6−0.2 (3)C16—O3—C13—C120.5 (2)
C2—C1—C6—C5−1.3 (3)C16—O3—C13—C14−179.34 (15)
C2—C1—C6—C7178.43 (16)C11—C12—C13—O3179.13 (17)
O1—C5—C6—C1−179.10 (17)C11—C12—C13—C14−1.0 (3)
C4—C5—C6—C11.0 (3)O3—C13—C14—C15−179.48 (16)
O1—C5—C6—C71.1 (3)C12—C13—C14—C150.6 (3)
C4—C5—C6—C7−178.82 (16)C13—C14—C15—C10−0.2 (3)
C1—C6—C7—O2−179.21 (18)C11—C10—C15—C140.1 (3)
C5—C6—C7—O20.6 (3)C9—C10—C15—C14−178.55 (17)
C1—C6—C7—C80.2 (3)C13—O3—C16—C17−178.12 (14)
C5—C6—C7—C8179.95 (16)O3—C16—C17—C18−179.87 (14)
O2—C7—C8—C9−3.6 (3)C16—C17—C18—C19179.43 (15)
C6—C7—C8—C9177.02 (16)C17—C18—C19—C20−179.30 (15)
C7—C8—C9—C10178.62 (18)C18—C19—C20—C21−179.83 (15)
C8—C9—C10—C15−5.4 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1O1···O20.90 (3)1.68 (3)2.507 (2)152 (2)
C20—H20A···Cg1i0.972.843.657 (2)142
C20—H20B···Cg1ii0.972.783.637 (2)147

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ2623).

References

  • Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl.34, 1555–1573.
  • Bhat, B. A., Dhar, K. L., Puri, S. C., Saxena, A. K., Shanmugavel, M. & Qazi, G. N. (2005). Bioorg. Med. Chem. Lett.15, 3177–3180. [PubMed]
  • Bruker (2005). APEX2, SAINT and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst.19, 105–107.
  • Lee, Y. S., Lim, S. S., Shin, K. H., Kim, Y. S., Ohuchi, K. & Jung, S. H. (2006). Biol. Pharm. Bull.29, 1028–1031. [PubMed]
  • Ngaini, Z., Fadzillah, S. M. H., Rahman, N. I. A., Hussain, H., Razak, I. A. & Fun, H.-K. (2009). Acta Cryst. E65, o879–o880. [PMC free article] [PubMed]
  • Ngaini, Z., Rahman, N. I. A., Hussain, H., Razak, I. A. & Fun, H.-K. (2009). Acta Cryst. E65, o889–o890. [PMC free article] [PubMed]
  • Razak, I. A., Fun, H.-K., Ngaini, Z., Fadzillah, S. M. H. & Hussain, H. (2009a). Acta Cryst. E65, o881–o882. [PMC free article] [PubMed]
  • Razak, I. A., Fun, H.-K., Ngaini, Z., Fadzillah, S. M. H. & Hussain, H. (2009b). Acta Cryst. E65, o1133–o1134. [PMC free article] [PubMed]
  • Razak, I. A., Fun, H.-K., Ngaini, Z., Rahman, N. I. A. & Hussain, H. (2009). Acta Cryst. E65, o1092–o1093. [PMC free article] [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]
  • Xue, C. X., Cui, S. Y., Liu, M. C., Hu, Z. D. & Fan, B. T. (2004). Eur. J. Med. Chem.39, 745–753. [PubMed]
  • Zhao, L. M., Jin, H. S., Sun, L. P., Piao, H. R. & Quan, Z. S. (2005). Chem. Lett.15, 5027–5029. [PubMed]

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