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 October 1; 65(Pt 10): o2445.
Published online 2009 September 12. doi:  10.1107/S160053680903579X
PMCID: PMC2970464

3,3-Dimethyl-cis-2,6-di-p-tolyl­piperidin-4-one

Abstract

In the title mol­ecule, C21H25NO, the piperidine ring adopts a chair conformation. The benzene rings and one of the methyl groups attached to the piperidine ring have equatorial orientations. The dihedral angle between the two benzene rings is 72.53 (9)°. In the crystal, mol­ecules are linked by N—H(...)O hydrogen bonds. Weak C—H(...)π inter­actions involving the benzene rings are also present in the crystal structure.

Related literature

For related crystal structures, see: Gayathri et al. (2008 [triangle]); Ilango et al. (2008 [triangle]). For biological activities of piperidones, see: Aridoss et al. (2008 [triangle]). For the synthesis, see: Noller and Baliah (1948 [triangle]). For the stereochemistry and ring conformation of piperidin-4-ones and their derivatives, see: Ponnuswamy et al. (2002 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o2445-scheme1.jpg

Experimental

Crystal data

  • C21H25NO
  • M r = 307.42
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2445-efi1.jpg
  • a = 12.9576 (3) Å
  • b = 22.6153 (5) Å
  • c = 5.9600 (1) Å
  • V = 1746.52 (6) Å3
  • Z = 4
  • Cu Kα radiation
  • μ = 0.55 mm−1
  • T = 110 K
  • 0.51 × 0.34 × 0.12 mm

Data collection

  • Oxford Diffraction Xcalibur diffractometer with a Ruby Gemini detector
  • Absorption correction: multi-scan (CrysAlis Pro; Oxford Diffraction, 2009 [triangle]) T min = 0.665, T max = 1.000
  • 4198 measured reflections
  • 1914 independent reflections
  • 1859 reflections with I > 2σ(I)
  • R int = 0.018

Refinement

  • R[F 2 > 2σ(F 2)] = 0.039
  • wR(F 2) = 0.106
  • S = 1.04
  • 1914 reflections
  • 216 parameters
  • 1 restraint
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.26 e Å−3
  • Δρmin = −0.24 e Å−3

Data collection: CrysAlis Pro (Oxford Diffraction, 2009 [triangle]); cell refinement: CrysAlis Pro; data reduction: CrysAlis Pro; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]); software used to prepare material for publication: PLATON (Spek, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680903579X/sj2644sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680903579X/sj2644Isup2.hkl

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

Acknowledgments

RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.

supplementary crystallographic information

Comment

Piperidin-4-ones and their derivatives show a broad spectrum of biological activity which includes antimicrobial, antiviral, anti tuberculosis and anticancer activities (Aridoss et al., 2008). Recent research effort has been devoted to the discovery of potential 2,6-diarylpiperidin-4-one based chemical entities and establishing their stereochemistry, (Ponnuswamy et al., 2002) because, the pharmacological effects of potential drugs depends sensitively on the stereochemistry and ring conformations.

Crystal structures of r-2,c-6-Bis(4-chlorophenyl)-t-3-isopropyl-1-nitrosopiperidin-4-one (Gayathri et al., 2008) and r-2,c-6-Bis(4-chlorophenyl)-c-3,t-3- dimethylpiperidin-4-one(Ilango et al., 2008) have been reported, wherein the piperidine rings adopt chair conformations.

In the title molecule, C21H25NO, Fig.1, the piperidine ring adopts a chair conformation. The benzene rings at position 2,6 and one of the methyl groups attached to the piperidine ring in 3, have equatorial orientations. The dihedral angle between the two benzene rings is 72.53 (9)°. Molecules are linked by intermolecular N1—H1···O4 (-1/2 + x, 1/2 - y, z)hydrogen bonds, forming an infinite one-dimensional chain with base vector [1 0 0]. Further, C16—H16B···π (1/2 - x, 1/2 + y, -1/2 + z) and C32—H32A···π (1/2 + x, 1/2 - y, z) interactions involving the benzene rings at position 2 (C21—C26) and 6 (C61—C66) are also present in the crystal structure.

Experimental

The procedure adopted by Noller & Baliah (1948) was followed for the preparation of the title compound. To the solution of ammonium acetate (3.85 g, 0.05 mol) in dry ethanol, p-tolualdehyde (12.0 g, 0.1 mol) and isopropyl methyl ketone (5.35 ml, 0.05 mol) were added and allowed to reflux on a water bath for 1 h. The resulting solution was kept at room temperature for overnight and the precipitated solid was filtered. The solid was crystallized using benzene - petroleum ether mixture. The yield of the product obtained was 7.36 g (48%).

Refinement

In the absence of any anamalous scatterers in the molecule, the Friedel pairs were merged. The absolute structure in the present model has been chosen arbitrarily. Atom H1 on N1 was located in a difference Fourier map and refined isotropically. Remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with C—H = 0.95, 0.98, 0.99 and 1.00 Å for Csp2, methyl, methylene and methine C, respectively; Uiso(H) = kUeq(C), where k = 1.5 for methyl and 1.2 for all other H atoms.

Figures

Fig. 1.
The molecular structure of the title compound, showing the atom-numbering scheme and displacement ellipsoids drawn at the 30% probability level. H atoms are shown as small spheres of arbitrary radius.
Fig. 2.
The molecular packing of the title compound, viewed down the c axis. Dashed lines indicate hydrogen bonds. H atoms not involved in hydrogen bonding have been omitted.

Crystal data

C21H25NODx = 1.169 Mg m3
Mr = 307.42Melting point: 389(1) K
Orthorhombic, Pna21Cu Kα radiation, λ = 1.54184 Å
Hall symbol: P 2c -2nCell parameters from 3875 reflections
a = 12.9576 (3) Åθ = 5.2–74.0°
b = 22.6153 (5) ŵ = 0.55 mm1
c = 5.9600 (1) ÅT = 110 K
V = 1746.52 (6) Å3Rectangular-plate, colourless
Z = 40.51 × 0.34 × 0.12 mm
F(000) = 664

Data collection

Oxford Diffraction Xcalibur diffractometer with a Ruby Gemini detector1914 independent reflections
Radiation source: fine-focus sealed tube1859 reflections with I > 2σ(I)
graphiteRint = 0.018
Detector resolution: 10.5081 pixels mm-1θmax = 74.1°, θmin = 5.2°
ω scansh = −16→8
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)k = −27→16
Tmin = 0.665, Tmax = 1.000l = −6→7
4198 measured reflections

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)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106H atoms treated by a mixture of independent and constrained refinement
S = 1.04w = 1/[σ2(Fo2) + (0.0807P)2 + 0.2385P] where P = (Fo2 + 2Fc2)/3
1914 reflections(Δ/σ)max = 0.001
216 parametersΔρmax = 0.26 e Å3
1 restraintΔρmin = −0.24 e Å3

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles
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 > 2σ(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
O40.56853 (10)0.24999 (6)−0.0992 (3)0.0283 (4)
N10.27975 (12)0.27483 (7)0.1089 (3)0.0224 (4)
C20.31792 (13)0.21482 (8)0.0700 (3)0.0211 (5)
C30.43464 (13)0.21033 (8)0.1375 (3)0.0231 (5)
C40.49127 (14)0.25941 (8)0.0097 (4)0.0239 (5)
C50.44461 (14)0.32042 (8)0.0236 (4)0.0281 (5)
C60.32911 (14)0.31839 (8)−0.0373 (3)0.0236 (5)
C120.04818 (17)0.04740 (9)0.5387 (4)0.0352 (6)
C160.11057 (17)0.54217 (9)0.0765 (4)0.0342 (6)
C210.24918 (13)0.17115 (8)0.1927 (3)0.0213 (5)
C220.22517 (14)0.11643 (8)0.0988 (4)0.0242 (5)
C230.16130 (14)0.07669 (8)0.2094 (4)0.0259 (5)
C240.11876 (14)0.09021 (8)0.4177 (4)0.0259 (5)
C250.14229 (15)0.14503 (8)0.5111 (4)0.0259 (5)
C260.20649 (14)0.18499 (8)0.4018 (4)0.0230 (5)
C310.45077 (15)0.22090 (9)0.3902 (4)0.0286 (5)
C320.47915 (15)0.15041 (8)0.0708 (4)0.0295 (6)
C610.27612 (14)0.37750 (8)−0.0106 (3)0.0234 (5)
C620.27803 (15)0.40730 (9)0.1934 (4)0.0281 (5)
C630.22477 (17)0.46020 (9)0.2216 (4)0.0301 (6)
C640.16765 (15)0.48444 (8)0.0463 (4)0.0278 (5)
C650.16612 (16)0.45467 (9)−0.1565 (4)0.0285 (5)
C660.21927 (15)0.40169 (9)−0.1854 (4)0.0275 (5)
H10.216 (2)0.2763 (10)0.077 (5)0.023 (6)*
H20.312460.20644−0.094290.0253*
H5A0.481150.34728−0.080760.0338*
H5B0.452940.336100.177640.0338*
H60.321930.30512−0.196550.0283*
H12A−0.022400.051890.482130.0528*
H12B0.049470.055770.700010.0528*
H12C0.071800.006820.512260.0528*
H16A0.050830.54316−0.024330.0513*
H16B0.156790.575180.041060.0513*
H16C0.087060.545610.232200.0513*
H220.253010.10614−0.043350.0290*
H230.146360.039630.141730.0311*
H250.113840.155360.652670.0311*
H260.221490.222010.469700.0276*
H31A0.524720.224610.421680.0428*
H31B0.422470.187470.474860.0428*
H31C0.415380.257330.434960.0428*
H32A0.551890.148460.115190.0441*
H32B0.473530.14536−0.092010.0441*
H32C0.440600.118910.146540.0441*
H620.316220.391320.315230.0337*
H630.227390.480020.362020.0361*
H650.128080.47069−0.278480.0342*
H660.216590.38193−0.325910.0330*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O40.0233 (6)0.0338 (7)0.0279 (7)0.0004 (5)0.0018 (6)0.0032 (6)
N10.0197 (7)0.0216 (8)0.0258 (8)−0.0004 (5)0.0003 (7)0.0018 (7)
C20.0223 (8)0.0218 (8)0.0192 (9)−0.0003 (6)−0.0006 (7)−0.0001 (7)
C30.0201 (8)0.0253 (9)0.0238 (10)0.0003 (7)−0.0005 (7)0.0015 (8)
C40.0215 (8)0.0270 (8)0.0233 (9)−0.0013 (7)−0.0022 (8)−0.0006 (8)
C50.0240 (8)0.0234 (9)0.0370 (11)−0.0022 (7)0.0040 (8)0.0027 (8)
C60.0256 (9)0.0220 (8)0.0231 (9)0.0003 (7)0.0014 (7)0.0001 (7)
C120.0374 (10)0.0292 (9)0.0390 (12)−0.0069 (8)0.0044 (10)0.0088 (10)
C160.0349 (10)0.0258 (9)0.0419 (13)0.0039 (7)0.0066 (10)0.0033 (9)
C210.0199 (8)0.0218 (8)0.0222 (9)0.0011 (6)−0.0017 (7)0.0022 (8)
C220.0247 (8)0.0249 (9)0.0229 (9)0.0009 (6)−0.0008 (8)−0.0023 (8)
C230.0285 (8)0.0196 (8)0.0297 (10)−0.0008 (7)−0.0045 (8)−0.0002 (8)
C240.0234 (8)0.0242 (8)0.0302 (10)−0.0009 (7)−0.0015 (8)0.0065 (8)
C250.0260 (9)0.0284 (9)0.0232 (9)0.0017 (7)0.0017 (8)0.0012 (8)
C260.0238 (8)0.0207 (8)0.0245 (9)0.0006 (6)−0.0002 (8)−0.0011 (8)
C310.0261 (9)0.0365 (10)0.0232 (9)−0.0027 (8)−0.0045 (8)0.0023 (9)
C320.0263 (9)0.0251 (9)0.0370 (11)0.0023 (7)0.0033 (8)0.0027 (9)
C610.0242 (8)0.0218 (8)0.0242 (10)−0.0022 (7)0.0047 (8)0.0032 (8)
C620.0330 (9)0.0271 (9)0.0243 (10)0.0007 (7)−0.0023 (9)0.0037 (9)
C630.0388 (10)0.0257 (9)0.0257 (10)−0.0011 (8)0.0019 (9)−0.0023 (8)
C640.0260 (8)0.0229 (9)0.0344 (11)−0.0018 (7)0.0069 (8)0.0037 (9)
C650.0301 (9)0.0284 (9)0.0270 (10)0.0000 (7)0.0009 (8)0.0085 (8)
C660.0315 (10)0.0284 (9)0.0226 (9)−0.0016 (8)0.0013 (8)0.0008 (8)

Geometric parameters (Å, °)

O4—C41.212 (2)C65—C661.393 (3)
N1—C21.463 (2)C2—H21.0000
N1—C61.463 (2)C5—H5A0.9900
N1—H10.85 (3)C5—H5B0.9900
C2—C211.518 (2)C6—H61.0000
C2—C31.568 (2)C12—H12A0.9800
C3—C41.533 (3)C12—H12B0.9800
C3—C311.539 (3)C12—H12C0.9800
C3—C321.525 (3)C16—H16A0.9800
C4—C51.509 (3)C16—H16B0.9800
C5—C61.541 (3)C16—H16C0.9800
C6—C611.511 (3)C22—H220.9500
C12—C241.515 (3)C23—H230.9500
C16—C641.511 (3)C25—H250.9500
C21—C221.393 (3)C26—H260.9500
C21—C261.399 (3)C31—H31A0.9800
C22—C231.388 (3)C31—H31B0.9800
C23—C241.392 (3)C31—H31C0.9800
C24—C251.393 (3)C32—H32A0.9800
C25—C261.390 (3)C32—H32B0.9800
C61—C661.388 (3)C32—H32C0.9800
C61—C621.390 (3)C62—H620.9500
C62—C631.391 (3)C63—H630.9500
C63—C641.393 (3)C65—H650.9500
C64—C651.384 (3)C66—H660.9500
O4···C21i3.419 (2)H5B···C24i3.0700
O4···N1i3.057 (2)H6···H22.3200
O4···H32B2.6700H6···H662.3400
O4···H32A2.6400H12B···H252.4200
O4···H1i2.26 (3)H12C···H232.5200
O4···H25ii2.6700H16A···H652.4500
N1···O4iii3.057 (2)H16B···C23vii3.0800
N1···H31C2.6500H16B···C24vii3.0200
N1···H622.9500H16B···C25vii3.0500
N1···H262.5700H16C···H632.4700
C21···O4iii3.419 (2)H22···H22.4100
C22···C323.384 (3)H23···H12C2.5200
C26···C313.269 (3)H25···H12B2.4200
C31···C263.269 (3)H25···O4viii2.6700
C32···C223.384 (3)H25···H5Aviii2.3400
C4···H1i3.05 (3)H26···N12.5700
C5···H622.8900H26···C313.0100
C5···H31C2.8600H31A···H32A2.5400
C21···H32C2.7600H31B···C212.8300
C21···H31B2.8300H31B···C262.8300
C22···H32C2.8100H31B···H32C2.5100
C23···H16Biv3.0800H31C···N12.6500
C24···H5Biii3.0700H31C···C52.8600
C24···H16Biv3.0200H31C···H5B2.4000
C25···H16Biv3.0500H32A···O42.6400
C26···H12.83 (3)H32A···H31A2.5400
C26···H31B2.8300H32A···C61i3.0600
C31···H5B2.9000H32A···C66i3.0300
C31···H263.0100H32B···O42.6700
C61···H32Aiii3.0600H32B···H22.5000
C62···H5B2.7800H32C···C212.7600
C62···H66v3.0300H32C···C222.8100
C65···H63vi3.0300H32C···H31B2.5100
C66···H32Aiii3.0300H62···N12.9500
H1···C262.83 (3)H62···C52.8900
H1···O4iii2.26 (3)H62···H5B2.3200
H1···C4iii3.05 (3)H62···H66v2.5100
H2···H62.3200H63···C65v3.0300
H2···H222.4100H63···H16C2.4700
H2···H32B2.5000H63···H65v2.5100
H5A···H25ii2.3400H65···H16A2.4500
H5B···C312.9000H65···H63vi2.5100
H5B···C622.7800H66···C62vi3.0300
H5B···H31C2.4000H66···H62.3400
H5B···H622.3200H66···H62vi2.5100
C2—N1—C6112.50 (15)C6—C5—H5B110.00
C6—N1—H1105.4 (18)H5A—C5—H5B108.00
C2—N1—H1109.3 (16)N1—C6—H6109.00
N1—C2—C21109.20 (14)C5—C6—H6109.00
N1—C2—C3110.21 (14)C61—C6—H6109.00
C3—C2—C21113.59 (14)C24—C12—H12A109.00
C2—C3—C31111.83 (14)C24—C12—H12B109.00
C2—C3—C4106.69 (14)C24—C12—H12C109.00
C4—C3—C32109.43 (15)H12A—C12—H12B109.00
C31—C3—C32109.98 (16)H12A—C12—H12C109.00
C4—C3—C31107.98 (16)H12B—C12—H12C109.00
C2—C3—C32110.81 (15)C64—C16—H16A109.00
O4—C4—C5121.41 (18)C64—C16—H16B109.00
O4—C4—C3122.29 (16)C64—C16—H16C109.00
C3—C4—C5116.30 (16)H16A—C16—H16B109.00
C4—C5—C6110.43 (15)H16A—C16—H16C109.00
N1—C6—C5107.73 (15)H16B—C16—H16C109.00
C5—C6—C61112.97 (15)C21—C22—H22119.00
N1—C6—C61109.54 (15)C23—C22—H22119.00
C2—C21—C26121.04 (16)C22—C23—H23119.00
C2—C21—C22121.03 (17)C24—C23—H23119.00
C22—C21—C26117.92 (17)C24—C25—H25119.00
C21—C22—C23121.2 (2)C26—C25—H25119.00
C22—C23—C24121.15 (18)C21—C26—H26120.00
C23—C24—C25117.72 (18)C25—C26—H26120.00
C12—C24—C25120.7 (2)C3—C31—H31A109.00
C12—C24—C23121.55 (17)C3—C31—H31B109.00
C24—C25—C26121.5 (2)C3—C31—H31C109.00
C21—C26—C25120.57 (18)H31A—C31—H31B109.00
C62—C61—C66118.34 (18)H31A—C31—H31C109.00
C6—C61—C62120.85 (16)H31B—C31—H31C109.00
C6—C61—C66120.71 (17)C3—C32—H32A109.00
C61—C62—C63120.9 (2)C3—C32—H32B109.00
C62—C63—C64120.8 (2)C3—C32—H32C109.00
C16—C64—C65121.2 (2)H32A—C32—H32B109.00
C16—C64—C63120.7 (2)H32A—C32—H32C109.00
C63—C64—C65118.12 (18)H32B—C32—H32C109.00
C64—C65—C66121.3 (2)C61—C62—H62120.00
C61—C66—C65120.6 (2)C63—C62—H62120.00
N1—C2—H2108.00C62—C63—H63120.00
C3—C2—H2108.00C64—C63—H63120.00
C21—C2—H2108.00C64—C65—H65119.00
C4—C5—H5A110.00C66—C65—H65119.00
C4—C5—H5B110.00C61—C66—H66120.00
C6—C5—H5A110.00C65—C66—H66120.00
C6—N1—C2—C365.65 (19)N1—C6—C61—C6263.7 (2)
C6—N1—C2—C21−168.91 (14)N1—C6—C61—C66−112.47 (19)
C2—N1—C6—C5−64.42 (19)C5—C6—C61—C62−56.4 (2)
C2—N1—C6—C61172.34 (14)C5—C6—C61—C66127.44 (19)
N1—C2—C3—C4−53.85 (19)C2—C21—C22—C23−179.21 (17)
N1—C2—C3—C3164.01 (19)C26—C21—C22—C23−0.3 (3)
N1—C2—C3—C32−172.90 (16)C2—C21—C26—C25178.97 (17)
C21—C2—C3—C4−176.75 (15)C22—C21—C26—C250.1 (3)
C21—C2—C3—C31−58.9 (2)C21—C22—C23—C240.2 (3)
C21—C2—C3—C3264.2 (2)C22—C23—C24—C12179.41 (19)
N1—C2—C21—C22142.56 (17)C22—C23—C24—C250.1 (3)
N1—C2—C21—C26−36.3 (2)C12—C24—C25—C26−179.65 (19)
C3—C2—C21—C22−94.0 (2)C23—C24—C25—C26−0.4 (3)
C3—C2—C21—C2687.2 (2)C24—C25—C26—C210.3 (3)
C2—C3—C4—O4−129.7 (2)C6—C61—C62—C63−176.61 (18)
C2—C3—C4—C549.4 (2)C66—C61—C62—C63−0.3 (3)
C31—C3—C4—O4109.9 (2)C6—C61—C66—C65176.65 (18)
C31—C3—C4—C5−71.0 (2)C62—C61—C66—C650.4 (3)
C32—C3—C4—O4−9.8 (3)C61—C62—C63—C640.4 (3)
C32—C3—C4—C5169.34 (18)C62—C63—C64—C16−179.47 (19)
O4—C4—C5—C6127.7 (2)C62—C63—C64—C65−0.5 (3)
C3—C4—C5—C6−51.4 (2)C16—C64—C65—C66179.51 (19)
C4—C5—C6—N154.8 (2)C63—C64—C65—C660.5 (3)
C4—C5—C6—C61175.93 (17)C64—C65—C66—C61−0.5 (3)

Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) x+1/2, −y+1/2, z−1; (iii) x−1/2, −y+1/2, z; (iv) −x+1/2, y−1/2, z+1/2; (v) x, y, z+1; (vi) x, y, z−1; (vii) −x+1/2, y+1/2, z−1/2; (viii) x−1/2, −y+1/2, z+1.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H1···O4iii0.85 (3)2.26 (3)3.057 (2)157 (2)
C16—H16B···Cg1vii0.982.803.704 (2)154
C32—H32A···Cg2i0.982.903.659 (2)135

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ2644).

References

  • Aridoss, G., Amirthaganesan, S., Ashok Kumar, N., Kim, J. T., Lim, K. T., Kabilan, S. & Jeong, Y. T. (2008). Bioorg. Med. Chem. Lett.18, 6542–6548. [PubMed]
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Gayathri, P., Thiruvalluvar, A., Manimekalai, A., Sivakumar, S. & Butcher, R. J. (2008). Acta Cryst. E64, o1973. [PMC free article] [PubMed]
  • Ilango, S. S., Ponnuswamy, S., Gayathri, P., Thiruvalluvar, A. & Butcher, R. J. (2008). Acta Cryst. E64, o2312. [PMC free article] [PubMed]
  • Noller, C. & Baliah, V. (1948). J. Am. Chem. Soc.70, 3853–3855. [PubMed]
  • Oxford Diffraction (2009). CrysAlis Pro. Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.
  • Ponnuswamy, S., Venkatraj, M., Jeyaraman, R., Suresh Kumar, M., Kumaran, D. & Ponnuswamy, M. N. (2002). Indian J. Chem. Sect. B, 41, 614–627.
  • Sheldrick, G. M. (2008). Acta Cryst A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]

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