supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportcited insimilar papers Open access

Acta Cryst. (2010). E66, o91-o92    [ doi:10.1107/S1600536809052179 ]

1-(6-Chloro-2-methyl-4-phenylquinolin-3-yl)-3-(3-methoxyphenyl)prop-2-en-1-one

W.-S. Loh, H.-K. Fun, S. Sarveswari, V. Vijayakumar and B. P. Reddy

Abstract top

In the title compound, C26H20ClNO2, the quinoline ring system is approximately planar with a maximum deviation of 0.028 (2) Å and forms a dihedral angle of 73.84 (5)° with the phenyl ring. Two neighbouring molecules are arranged into a centrosymmetric dimer through a pair of intermolecular C-H...Cl interactions. A pair of intermolecular C-H...O hydrogen bonds link two methoxyphenyl groups into another centrosymmetric dimer, generating an R22(8) ring motif. The structure is further stabilized by C-H...[pi] interactions.

Comment top

The quinolines and their derivatives are very important compounds because of their wide occurrence in natural products (Michael, 1997) and biologically active compounds (Markees et al., 1970). A large variety of quinolines have interesting physiological activities and found attractive applications as pharmaceuticals, agrochemicals and as synthetic building blocks (Kalluraya & Sreenivasa, 1998; Chen et al., 2001). The chalcones are open-chain flavonoids, possessing a variety of biological activities, including antioxidant, anti-inflammation, antimicrobial, antiprotozoal, antiulcer, as well as other properties (Dimmock et al., 1999). Importantly, chalcones have shown several anticancer activities as inhibitors of cancer cell proliferation, carcinogenesis and metastasis (Zi & Simoneau, 2005).

In the title compound (Fig. 1), the quinoline ring system (C1–C9/N1) is approximately planar with a maximum deviation of 0.036 (1) Å at atom C11. This mean plane of quinoline ring forms a dihedral angle of 73.84 (5)° with the phenyl ring (C19–C24). Bond lengths (Allen et al., 1987) and angles are within the normal range and are comparable to closely related structures (Fun et al., 2009; Loh et al., 2009).

In the crystal packing (Fig. 2), two molecules are arranged into a large dimer by a pair of intermolecular C18—H18A···Cl1 interactions. A pair of intermolecular C16—H16A···O2 hydrogen bonds link two methoxyphenyl groups of the neighbouring molecules into another set of dimer, generating an R22(8) ring motif (Bernstein et al., 1995). The crystal structure is further stabilized by C—H···π interactions (Table 1), involving C13–C18 (centroid Cg1) and C19–C24 (centroid Cg2) rings.

Related literature top

For background to and the biological activity of quinolines, see: Michael (1997); Markees et al. (1970); Kalluraya & Sreenivasa (1998); Chen et al. (2001). For the biological activity of chalcones, see: Dimmock et al. (1999); Zi & Simoneau (2005). For related structures, see: Fun et al. (2009); Loh et al. (2009). For hydrogen-bond motifs, see: Bernstein et al. (1995). For bond-length data, see: Allen et al. (1987). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental top

To the solution of 3-acetyl-6-chloro-2-methyl-4-phenylquinoline (2.95 g, 0.01 M), 3-methoxybenzaldehyde (1.36 g, 0.01 M) and a catalytic amount of KOH in distilled ethanol was added and stirred for about 12 h. The resulting mixture was concentrated to remove the ethanol and then poured onto ice and neutralized with diluted acetic acid. The resultant solid was filtered, dried and purified by column chromatography using 1:1 mixture of ethylacetate and petroleum ether (m.p. 405–407 K).

Refinement top

All hydrogen atoms were positioned geometrically (C–H = 0.93 or 0.96 Å) and were refined using a riding model, with Uiso(H) = 1.2 or 1.5Ueq(C). A rotating group model was applied to the methyl groups.

Computing details top

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

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.
[Figure 2] Fig. 2. The crystal packing of the title compound, viewed along the c axis. H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.
1-(6-Chloro-2-methyl-4-phenylquinolin-3-yl)-3-(3-methoxyphenyl)prop-2-en-1-one top
Crystal data top
C26H20ClNO2F(000) = 864
Mr = 413.88Dx = 1.316 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9882 reflections
a = 15.6338 (2) Åθ = 2.6–30.3°
b = 14.0408 (2) ŵ = 0.21 mm−1
c = 10.0321 (1) ÅT = 100 K
β = 108.462 (1)°Block, colourless
V = 2088.82 (5) Å30.33 × 0.25 × 0.17 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		6303 independent reflections
Radiation source: fine-focus sealed tube5132 reflections with I > 2σ(I)
graphiteRint = 0.042
φ and ω scansθmax = 30.4°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)		h = −22→22
Tmin = 0.936, Tmax = 0.967k = −19→19
51550 measured reflectionsl = −14→14
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.112H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0521P)2 + 0.7676P]
where P = (Fo2 + 2Fc2)/3
6303 reflections(Δ/σ)max = 0.001
273 parametersΔρmax = 0.38 e Å−3
0 restraintsΔρmin = −0.40 e Å−3
Crystal data top
C26H20ClNO2V = 2088.82 (5) Å3
Mr = 413.88Z = 4
Monoclinic, P21/cMo Kα radiation
a = 15.6338 (2) ŵ = 0.21 mm−1
b = 14.0408 (2) ÅT = 100 K
c = 10.0321 (1) Å0.33 × 0.25 × 0.17 mm
β = 108.462 (1)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		6303 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)		5132 reflections with I > 2σ(I)
Tmin = 0.936, Tmax = 0.967Rint = 0.042
51550 measured reflectionsθmax = 30.4°
Refinement top
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.112Δρmax = 0.38 e Å−3
S = 1.05Δρmin = −0.40 e Å−3
6303 reflectionsAbsolute structure: ?
273 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems 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) top
xyzUiso*/Ueq
Cl10.33917 (2)0.33164 (3)0.58574 (4)0.03525 (10)
O10.89366 (6)0.37834 (7)0.92588 (10)0.0275 (2)
O20.99503 (6)0.88427 (6)1.10271 (9)0.02503 (19)
N10.69406 (7)0.37222 (7)0.50187 (10)0.0202 (2)
C10.76533 (8)0.39716 (8)0.60758 (12)0.0194 (2)
C20.61229 (8)0.36683 (8)0.52489 (12)0.0186 (2)
C30.53676 (9)0.33562 (9)0.41238 (13)0.0232 (2)
H3A0.54370.32200.32570.028*
C40.45373 (9)0.32536 (9)0.42991 (13)0.0245 (3)
H4A0.40460.30440.35600.029*
C50.44385 (8)0.34703 (10)0.56185 (13)0.0230 (2)
C60.51471 (8)0.37833 (9)0.67275 (12)0.0208 (2)
H6A0.50630.39260.75830.025*
C70.60098 (8)0.38886 (8)0.65627 (11)0.0175 (2)
C80.67867 (8)0.41709 (8)0.76909 (11)0.0170 (2)
C90.76028 (7)0.41997 (8)0.74412 (12)0.0174 (2)
C100.84595 (8)0.44340 (9)0.86210 (12)0.0195 (2)
C110.87075 (8)0.54318 (9)0.89574 (13)0.0217 (2)
H11A0.92000.55640.97440.026*
C120.82630 (8)0.61647 (9)0.81913 (13)0.0204 (2)
H12A0.77520.60200.74410.024*
C130.85050 (7)0.71727 (9)0.84237 (12)0.0191 (2)
C140.91311 (8)0.74920 (9)0.96894 (12)0.0196 (2)
H14A0.93810.70671.04200.024*
C150.93706 (8)0.84453 (9)0.98366 (12)0.0198 (2)
C160.90136 (8)0.90856 (9)0.87281 (13)0.0226 (2)
H16A0.91930.97200.88240.027*
C170.83926 (8)0.87700 (9)0.74883 (13)0.0227 (2)
H17A0.81520.91950.67530.027*
C180.81280 (8)0.78194 (9)0.73403 (13)0.0214 (2)
H18A0.76990.76140.65170.026*
C190.67020 (7)0.43834 (9)0.91020 (11)0.0177 (2)
C200.70262 (9)0.37333 (9)1.01947 (13)0.0233 (2)
H20A0.73250.31871.00580.028*
C210.69045 (9)0.38998 (10)1.14923 (13)0.0269 (3)
H21A0.71150.34611.22170.032*
C220.64704 (9)0.47190 (10)1.17049 (13)0.0260 (3)
H22A0.63890.48291.25710.031*
C230.61572 (9)0.53749 (10)1.06250 (13)0.0257 (3)
H23A0.58720.59281.07720.031*
C240.62681 (8)0.52078 (9)0.93238 (12)0.0221 (2)
H24A0.60530.56460.86000.027*
C250.85421 (9)0.40069 (11)0.57958 (14)0.0269 (3)
H25A0.84440.39180.48100.040*
H25B0.89280.35110.63160.040*
H25C0.88220.46140.60830.040*
C261.04176 (9)0.82146 (10)1.21483 (13)0.0257 (3)
H26A1.08080.85791.29080.038*
H26B1.07690.77691.18150.038*
H26C0.99880.78751.24720.038*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.01933 (15)0.0596 (2)0.02639 (17)−0.01311 (14)0.00657 (12)−0.01568 (15)
O10.0238 (4)0.0259 (5)0.0278 (5)0.0019 (4)0.0009 (4)0.0005 (4)
O20.0280 (5)0.0226 (4)0.0205 (4)−0.0053 (3)0.0019 (4)−0.0048 (3)
N10.0225 (5)0.0224 (5)0.0164 (4)−0.0023 (4)0.0071 (4)−0.0014 (4)
C10.0212 (5)0.0193 (5)0.0189 (5)−0.0015 (4)0.0079 (4)0.0005 (4)
C20.0210 (5)0.0197 (5)0.0143 (5)−0.0027 (4)0.0047 (4)−0.0011 (4)
C30.0262 (6)0.0283 (6)0.0141 (5)−0.0031 (5)0.0050 (4)−0.0037 (4)
C40.0238 (6)0.0308 (7)0.0156 (5)−0.0056 (5)0.0015 (4)−0.0043 (5)
C50.0179 (5)0.0307 (7)0.0192 (5)−0.0043 (4)0.0042 (4)−0.0045 (5)
C60.0197 (5)0.0263 (6)0.0157 (5)−0.0039 (4)0.0046 (4)−0.0050 (4)
C70.0189 (5)0.0187 (5)0.0139 (5)−0.0022 (4)0.0038 (4)−0.0014 (4)
C80.0190 (5)0.0170 (5)0.0140 (5)−0.0016 (4)0.0036 (4)−0.0008 (4)
C90.0177 (5)0.0165 (5)0.0172 (5)−0.0019 (4)0.0045 (4)−0.0005 (4)
C100.0167 (5)0.0230 (6)0.0182 (5)−0.0017 (4)0.0046 (4)−0.0018 (4)
C110.0166 (5)0.0241 (6)0.0220 (6)−0.0034 (4)0.0026 (4)−0.0044 (5)
C120.0169 (5)0.0238 (6)0.0202 (5)−0.0043 (4)0.0054 (4)−0.0043 (4)
C130.0155 (5)0.0223 (6)0.0199 (5)−0.0024 (4)0.0060 (4)−0.0034 (4)
C140.0181 (5)0.0221 (6)0.0183 (5)−0.0025 (4)0.0053 (4)−0.0018 (4)
C150.0174 (5)0.0231 (6)0.0189 (5)−0.0030 (4)0.0057 (4)−0.0055 (4)
C160.0235 (6)0.0193 (6)0.0254 (6)−0.0012 (4)0.0083 (5)−0.0026 (5)
C170.0213 (5)0.0241 (6)0.0224 (6)0.0009 (4)0.0065 (5)0.0004 (5)
C180.0173 (5)0.0256 (6)0.0199 (5)−0.0007 (4)0.0040 (4)−0.0033 (4)
C190.0157 (5)0.0229 (6)0.0134 (5)−0.0045 (4)0.0029 (4)−0.0025 (4)
C200.0273 (6)0.0230 (6)0.0187 (5)−0.0007 (5)0.0059 (5)0.0003 (4)
C210.0320 (7)0.0307 (7)0.0169 (5)−0.0034 (5)0.0062 (5)0.0030 (5)
C220.0281 (6)0.0350 (7)0.0160 (5)−0.0076 (5)0.0086 (5)−0.0051 (5)
C230.0262 (6)0.0297 (7)0.0217 (6)0.0005 (5)0.0084 (5)−0.0056 (5)
C240.0226 (5)0.0257 (6)0.0168 (5)0.0007 (4)0.0042 (4)−0.0011 (4)
C250.0232 (6)0.0355 (7)0.0248 (6)−0.0028 (5)0.0115 (5)−0.0004 (5)
C260.0249 (6)0.0303 (7)0.0192 (6)−0.0043 (5)0.0034 (5)−0.0038 (5)
Geometric parameters (Å, °) top
Cl1—C51.7410 (12)C13—C141.4087 (16)
O1—C101.2239 (15)C14—C151.3852 (17)
O2—C151.3687 (14)C14—H14A0.9300
O2—C261.4340 (16)C15—C161.4012 (18)
N1—C11.3192 (15)C16—C171.3860 (17)
N1—C21.3713 (15)C16—H16A0.9300
C1—C91.4331 (16)C17—C181.3913 (18)
C1—C251.5030 (16)C17—H17A0.9300
C2—C71.4184 (15)C18—H18A0.9300
C2—C31.4200 (16)C19—C201.3927 (17)
C3—C41.3717 (18)C19—C241.3947 (17)
C3—H3A0.9300C20—C211.3938 (17)
C4—C51.4135 (17)C20—H20A0.9300
C4—H4A0.9300C21—C221.386 (2)
C5—C61.3703 (16)C21—H21A0.9300
C6—C71.4176 (16)C22—C231.3876 (19)
C6—H6A0.9300C22—H22A0.9300
C7—C81.4291 (15)C23—C241.3901 (17)
C8—C91.3765 (15)C23—H23A0.9300
C8—C191.4931 (15)C24—H24A0.9300
C9—C101.5163 (16)C25—H25A0.9600
C10—C111.4643 (17)C25—H25B0.9600
C11—C121.3395 (17)C25—H25C0.9600
C11—H11A0.9300C26—H26A0.9600
C12—C131.4644 (17)C26—H26B0.9600
C12—H12A0.9300C26—H26C0.9600
C13—C181.3956 (17)
C15—O2—C26117.77 (10)C13—C14—H14A120.3
C1—N1—C2118.32 (10)O2—C15—C14124.67 (11)
N1—C1—C9122.65 (10)O2—C15—C16114.72 (11)
N1—C1—C25117.00 (10)C14—C15—C16120.61 (11)
C9—C1—C25120.35 (11)C17—C16—C15119.79 (11)
N1—C2—C7122.80 (10)C17—C16—H16A120.1
N1—C2—C3117.91 (10)C15—C16—H16A120.1
C7—C2—C3119.27 (11)C16—C17—C18120.17 (12)
C4—C3—C2120.87 (11)C16—C17—H17A119.9
C4—C3—H3A119.6C18—C17—H17A119.9
C2—C3—H3A119.6C17—C18—C13120.21 (11)
C3—C4—C5119.07 (11)C17—C18—H18A119.9
C3—C4—H4A120.5C13—C18—H18A119.9
C5—C4—H4A120.5C20—C19—C24119.51 (11)
C6—C5—C4121.97 (11)C20—C19—C8119.73 (11)
C6—C5—Cl1118.79 (9)C24—C19—C8120.72 (10)
C4—C5—Cl1119.24 (9)C19—C20—C21120.13 (12)
C5—C6—C7119.55 (11)C19—C20—H20A119.9
C5—C6—H6A120.2C21—C20—H20A119.9
C7—C6—H6A120.2C22—C21—C20120.08 (12)
C6—C7—C2119.26 (10)C22—C21—H21A120.0
C6—C7—C8122.54 (10)C20—C21—H21A120.0
C2—C7—C8118.14 (10)C21—C22—C23119.98 (11)
C9—C8—C7117.92 (10)C21—C22—H22A120.0
C9—C8—C19122.16 (10)C23—C22—H22A120.0
C7—C8—C19119.86 (10)C22—C23—C24120.20 (12)
C8—C9—C1120.15 (10)C22—C23—H23A119.9
C8—C9—C10120.32 (10)C24—C23—H23A119.9
C1—C9—C10119.48 (10)C23—C24—C19120.10 (12)
O1—C10—C11121.37 (11)C23—C24—H24A120.0
O1—C10—C9119.18 (11)C19—C24—H24A120.0
C11—C10—C9119.44 (10)C1—C25—H25A109.5
C12—C11—C10123.47 (11)C1—C25—H25B109.5
C12—C11—H11A118.3H25A—C25—H25B109.5
C10—C11—H11A118.3C1—C25—H25C109.5
C11—C12—C13126.17 (11)H25A—C25—H25C109.5
C11—C12—H12A116.9H25B—C25—H25C109.5
C13—C12—H12A116.9O2—C26—H26A109.5
C18—C13—C14119.77 (11)O2—C26—H26B109.5
C18—C13—C12118.73 (11)H26A—C26—H26B109.5
C14—C13—C12121.45 (11)O2—C26—H26C109.5
C15—C14—C13119.40 (11)H26A—C26—H26C109.5
C15—C14—H14A120.3H26B—C26—H26C109.5
C2—N1—C1—C9−0.89 (17)C8—C9—C10—C11−84.74 (14)
C2—N1—C1—C25178.93 (11)C1—C9—C10—C1197.70 (13)
C1—N1—C2—C71.39 (17)O1—C10—C11—C12172.29 (12)
C1—N1—C2—C3−177.10 (11)C9—C10—C11—C12−6.60 (18)
N1—C2—C3—C4177.64 (12)C10—C11—C12—C13−176.37 (11)
C7—C2—C3—C4−0.90 (19)C11—C12—C13—C18163.13 (12)
C2—C3—C4—C50.5 (2)C11—C12—C13—C14−14.47 (18)
C3—C4—C5—C60.2 (2)C18—C13—C14—C15−0.56 (17)
C3—C4—C5—Cl1−178.61 (10)C12—C13—C14—C15177.02 (11)
C4—C5—C6—C7−0.5 (2)C26—O2—C15—C147.01 (17)
Cl1—C5—C6—C7178.35 (10)C26—O2—C15—C16−173.30 (11)
C5—C6—C7—C20.07 (18)C13—C14—C15—O2178.05 (11)
C5—C6—C7—C8−177.16 (12)C13—C14—C15—C16−1.62 (17)
N1—C2—C7—C6−177.85 (11)O2—C15—C16—C17−177.59 (11)
C3—C2—C7—C60.61 (17)C14—C15—C16—C172.11 (18)
N1—C2—C7—C8−0.50 (17)C15—C16—C17—C18−0.38 (18)
C3—C2—C7—C8177.97 (11)C16—C17—C18—C13−1.81 (18)
C6—C7—C8—C9176.38 (11)C14—C13—C18—C172.28 (17)
C2—C7—C8—C9−0.88 (16)C12—C13—C18—C17−175.37 (11)
C6—C7—C8—C19−1.07 (17)C9—C8—C19—C20−71.87 (15)
C2—C7—C8—C19−178.33 (10)C7—C8—C19—C20105.47 (13)
C7—C8—C9—C11.36 (16)C9—C8—C19—C24110.80 (13)
C19—C8—C9—C1178.75 (11)C7—C8—C19—C24−71.86 (15)
C7—C8—C9—C10−176.19 (10)C24—C19—C20—C211.01 (18)
C19—C8—C9—C101.20 (17)C8—C19—C20—C21−176.35 (11)
N1—C1—C9—C8−0.50 (18)C19—C20—C21—C22−0.8 (2)
C25—C1—C9—C8179.69 (11)C20—C21—C22—C230.0 (2)
N1—C1—C9—C10177.07 (11)C21—C22—C23—C240.7 (2)
C25—C1—C9—C10−2.74 (17)C22—C23—C24—C19−0.54 (19)
C8—C9—C10—O196.34 (14)C20—C19—C24—C23−0.33 (18)
C1—C9—C10—O1−81.22 (15)C8—C19—C24—C23177.01 (11)
Hydrogen-bond geometry (Å, °) top
Cg1 and Cg2 are the centroids of the C13–C18 and C19–C24 rings, resepctively.
D—H···AD—HH···AD···AD—H···A
C16—H16A···O2i0.932.403.3005 (15)163
C18—H18A···Cl1ii0.932.783.6948 (13)169
C26—H26B···O1iii0.962.543.4329 (17)155
C26—H26C···Cg1iv0.962.883.8412 (15)177
C17—H17A···Cg2v0.932.973.7592 (14)144
Symmetry codes: (i) −x+2, −y+2, −z+2; (ii) −x+1, −y+1, −z+1; (iii) −x+2, −y+1, −z+2; (iv) x, −y+1/2, z−1/2; (v) x, −y+1/2, z−3/2.
Table 1
Hydrogen-bond geometry (Å, °) top
Cg1 and Cg2 are the centroids of the C13–C18 and C19–C24 rings, resepctively.
D—H···AD—HH···AD···AD—H···A
C16—H16A···O2i0.932.403.3005 (15)163
C18—H18A···Cl1ii0.932.783.6948 (13)169
C26—H26B···O1iii0.962.543.4329 (17)155
C26—H26C···Cg1iv0.962.883.8412 (15)177
C17—H17A···Cg2v0.932.973.7592 (14)144
Symmetry codes: (i) −x+2, −y+2, −z+2; (ii) −x+1, −y+1, −z+1; (iii) −x+2, −y+1, −z+2; (iv) x, −y+1/2, z−1/2; (v) x, −y+1/2, z−3/2.
Acknowledgements top

WSL and HKF thank Universiti Sains Malaysia (USM) for the Research University Golden Goose Grant (1001/PFIZIK/811012). WSL thanks the Malaysian Government and USM for the award of the post of Assistant Research Officer under the Research University Golden Goose Grant (1001/PFIZIK/811012). VV is grateful to DST-India for funding through the Young Scientist Scheme (Fast Track Proposal).

references
References top

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.

Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.

Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.

Chen, Y.-L., Fang, K.-C., Sheu, J.-Y., Hsu, S.-L. & Tzeng, C.-C. (2001). J. Med. Chem. 44, 2374–2377.

Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107.

Dimmock, J. R., Elias, D. W., Beazely, M. A. & Kandepu, N. M. (1999). Curr. Med. Chem. pp. 1125–1149.

Fun, H.-K., Loh, W.-S., Sarveswari, S., Vijayakumar, V. & Reddy, B. P. (2009). Acta Cryst. E65, o2688–o2689.

Kalluraya, B. & Sreenivasa, S. (1998). Farmaco, 53, 399–404.

Loh, W.-S., Fun, H.-K., Sarveswari, S., Vijayakumar, V. & Reddy, B. P. (2009). Acta Cryst. E65, o3144–o3145.

Markees, D. G., Dewey, V. C. & Kidder, G. W. (1970). J. Med. Chem. 13, 324–326.

Michael, J. P. (1997). Nat. Prod. Rep. 14, 605–608.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Zi, X. & Simoneau, A. R. (2005). Cancer Res. 65, 3479–3486.