PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2010 June 1; 66(Pt 6): o1324–o1325.
Published online 2010 May 12. doi:  10.1107/S1600536810015709
PMCID: PMC2979526

4-[(2E)-2-(4-Chloro­benzyl­idene)hydrazinyl­idene]-1-methyl-1,4-dihydro­pyridine monohydrate

Abstract

In the title compound, C13H12ClN3·H2O, the organic mol­ecule is almost planar, with a dihedral angle of 3.22 (10)° between the benzene and pyridine rings. The crystal structure is stabilized by O—H(...)N and C—H(...)O hydrogen bonding and π–π stacking inter­actions [centroid–centroid distances = 3.630 (1) and 3.701 (1) Å].

Related literature

For the synthesis and pharmacological activity of (benzyl­idene-hydrazono)-1,4-dihydro­pyridine derivatives, see: Douglas et al. (1977 [triangle]); Alptüzün et al. (2010 [triangle]); Savini et al. (2002 [triangle]); Pandey et al. (2002 [triangle]); Salgın-Gökşen et al. (2007 [triangle]); Silva et al. (2004 [triangle]); Vicini et al. (2009 [triangle]). For bond-length data, see: Allen et al. (1987 [triangle]); Diao et al. (2008 [triangle]); Odabaşoğlu et al. (2003 [triangle]). For quantum-chemical calculations, see: Pople & Beveridge (1970 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o1324-scheme1.jpg

Experimental

Crystal data

  • C13H12ClN3·H2O
  • M r = 263.72
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1324-efi1.jpg
  • a = 5.8492 (4) Å
  • b = 20.3101 (10) Å
  • c = 12.2035 (7) Å
  • β = 113.855 (4)°
  • V = 1325.90 (14) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.28 mm−1
  • T = 296 K
  • 0.60 × 0.30 × 0.04 mm

Data collection

  • Stoe IPDS 2 diffractometer
  • Absorption correction: integration (X-RED32; Stoe & Cie, 2002 [triangle]) T min = 0.905, T max = 0.989
  • 14028 measured reflections
  • 2759 independent reflections
  • 1746 reflections with I > 2σ(I)
  • R int = 0.064

Refinement

  • R[F 2 > 2σ(F 2)] = 0.045
  • wR(F 2) = 0.095
  • S = 0.95
  • 2759 reflections
  • 170 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.16 e Å−3
  • Δρmin = −0.18 e Å−3

Data collection: X-AREA (Stoe & Cie, 2002 [triangle]); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002 [triangle]); program(s) used to solve structure: SIR97 (Altomare et al., 1999 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810015709/sj2782sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015709/sj2782Isup2.hkl

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

Acknowledgments

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS 2 diffractometer (purchased under grant F.279 of the University Research Fund).

supplementary crystallographic information

Comment

Hydrazones, a special group of compounds in the class of the schiff bases, are known to show significant biological activities including antimicrobial, antitubercular, anticancer, analgesic, anti-inflammatory, antiplatelet and antiviral activities (Savini et al., 2002; Pandey et al., 2002; Salgın-Gökşen et al., 2007; Silva et al., 2004; Vicini et al., 2009). In addition, (benzylidene-hydrazono)-1,4-dihydropyridine derivatives have anticoccidial activity (Douglas et al., 1977) and also display anti-Alzheimer's activity by inhibiting ABeta fibril formation and acetylcholinesterase (Alptüzün et al., 2010).

The title molecule (I), Fig. 1, crystallized as a monohydrate in the monoclinic space group P21/c. All bond lengths are as expected (Allen et al., 1987). The Cl1—C4, and N1—N2 bond lengths are 1.742 (2) Å, and 1.388 (2) Å, respectively. The Cl1—C4—C5 and N2—N1—C7 bond angles are 119.88 (18) ° and 113.95 (19) °, respectively. The bond lengths and the bond angles of (I) are comparable to those observed in related structures (Diao et al., 2008; Odabaşoğlu et al., 2003).

The main molecule is almost planar, except the methyl H atoms, forming a dihedral angle of 3.22 (10)° between the benzene (C1–C6) and dihydropyridine (N3/C8–C12) rings.

The crystal structure is stabilized by O—H···N and C—H···O hydrogen bonding (Table 1, Fig. 2) and π-π stacking interactions [Cg1···Cg1(-x, 1-y, -z) = 3.630 (1) Å and Cg1···Cg2(1-x, 1-y, 1-z) = 3.701 (1) Å, Cg1 and Cg2 are the centroids of the pyridine and benzene rings, respectively].

We have also carried out the quantum mechanical calculations using the CNDO (Pople et al., 1970) approximation. The spatial view of the single molecule considered in a vacuum, is shown in Fig.3. According to the theoretical CNDO and experimental X-rays results, the values of the geometric parameters of (I) are closely comparable within the observed experimental errors. The calculated dipole moment of (I) is about 11.481 Debye. The HOMO and LUMO energy levels are -8.3484 and 1.3565 eV, respectively.

Experimental

4-Hydrazinylpyridine (1.09 g, 0.01 mol) and 4-chlorobenzaldehyde (1.41 g, 0.01 mol) were stirred in ethanol (30 ml) at room temperature for 5-10 h. The precipitate was filtered and washed with cool ethanol and crystallized from ethanol. A mixture of 4-[(4-Chlorobenzylidene)hydrazinyl] pyridine (0.232 g, 0.001 mol) and methyl iodide (0.141 g, 0.002 mol) was refluxed in ethanol (20 ml) for 20 h. The mixture was cooled to room temperature and the resulting precipitate was filtered and washed with cool ethanol. The crude products were crystallized from ethanol to give the compound 4-(2-(4-Chlorobenzylidenehydrazinyl)-1-methylpyridinium iodide. This product (0.374 g, 0.001 mol) was partitioned between CH2Cl2 (50 ml) and 2 M NaOH (50 ml). The organic layer was evaporated to dryness and the residue recrystallized from ethanol-water.

Yield 88%, yellow needles, mp 407-409 K (lit. (Douglas et al. , 1977) 403-405 K). IR (KBr) vmax 1654, 1517, 1492, 1203, 824 cm-1. 1H-NMR (DMSO-d6): δ ppm 3.29 (3H, s, N—CH3), 6.12 (1H, dd, J=2.4/8.0 Hz, H-3 or H-5), 6.98 (1H, dd, J=2.0/7.8 Hz, H-3 or H-5), 7.23 (2H, td, J=7.2/2.0 Hz, H-2, H-6 ), 7.39 (2H, d, J=8.4 Hz, H-2', H-6'), 7.69 (2H, d, J=8.4 Hz, H-3', H-5'), 8.16 (1H, s, N=CH). 13 C NMR (CH3OH- d4): δ ppm 43.18 (q), 107.78 (d), 112.11 (d), 129.35 (d), 129.79 (d), 135.59 (s), 136.58 (s), 140.15 (d), 140.75 (d), 148.84 (d), 162.25 (s). EI—MS m/z (% relative intensity): 247 (M+2, 14), 246 (M+1, 28), 245 (M+, 43), 181 (25), 93 (100), 92 (24), 66 (30), 42 (18). C13H12N3Cl.H2O. C, H, N combustion analysis: Calc. (%) C 59.21, H 5.36, N 15.93; found (%) C 59.45, H 5.33, N 15.72.

Refinement

The H atoms of the water molecule were found from a difference Fourier map and their isotropic thermal parameters were refined by using a riding model with Uiso(H) = 1.5Ueq(O). Their positional parameters are refined freely [d(O–H) = 0.84 (3) and 0.91 (4) Å]. The remaining H atoms were positioned geometrically and refined using a riding model with C—H = 0.93 and 0.96 Å, and Uiso(H) = 1.2 or 1.5Ueq(C).

Figures

Fig. 1.
An ORTEP View of the title molecule with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level.
Fig. 2.
The packing and hydrogen bonding interactions of (I) down the a-axis. H atoms not participating in hydrogen bonding have been omitted for clarity.
Fig. 3.
The spatial view of the title molecule (I), calculated by the CNDO aproximation.

Crystal data

C13H12ClN3·H2OF(000) = 552
Mr = 263.72Dx = 1.321 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 11448 reflections
a = 5.8492 (4) Åθ = 1.8–27.3°
b = 20.3101 (10) ŵ = 0.28 mm1
c = 12.2035 (7) ÅT = 296 K
β = 113.855 (4)°Needle, yellow
V = 1325.90 (14) Å30.60 × 0.30 × 0.04 mm
Z = 4

Data collection

Stoe IPDS 2 diffractometer2759 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus1746 reflections with I > 2σ(I)
plane graphiteRint = 0.064
Detector resolution: 6.67 pixels mm-1θmax = 26.5°, θmin = 2.0°
ω scansh = −7→7
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)k = −25→25
Tmin = 0.905, Tmax = 0.989l = −15→15
14028 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)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H atoms treated by a mixture of independent and constrained refinement
S = 0.95w = 1/[σ2(Fo2) + (0.0426P)2] where P = (Fo2 + 2Fc2)/3
2759 reflections(Δ/σ)max < 0.001
170 parametersΔρmax = 0.16 e Å3
0 restraintsΔρmin = −0.18 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 esds are taken into account in the estimation of distances, angles and torsion angles
Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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
Cl11.22894 (12)0.72508 (3)0.80784 (5)0.0626 (2)
N10.3123 (3)0.56701 (10)0.35465 (13)0.0453 (6)
N20.0774 (3)0.54841 (9)0.27204 (13)0.0441 (6)
N30.0599 (4)0.39257 (9)0.05147 (14)0.0478 (6)
C10.5371 (4)0.63831 (11)0.52012 (15)0.0414 (7)
C20.5222 (4)0.69371 (12)0.58483 (16)0.0452 (7)
C30.7336 (4)0.72021 (11)0.67306 (16)0.0466 (7)
C40.9614 (4)0.69105 (12)0.69752 (16)0.0449 (7)
C50.9807 (4)0.63606 (12)0.63540 (16)0.0460 (8)
C60.7697 (4)0.60996 (12)0.54740 (16)0.0460 (7)
C70.3079 (4)0.61193 (11)0.42743 (16)0.0435 (7)
C80.0859 (4)0.49832 (11)0.20400 (15)0.0396 (7)
C90.3019 (4)0.46263 (11)0.21152 (16)0.0437 (7)
C100.2819 (4)0.41223 (12)0.13694 (18)0.0480 (7)
C11−0.1504 (4)0.42521 (12)0.04046 (17)0.0473 (7)
C12−0.1430 (4)0.47578 (12)0.11261 (16)0.0449 (7)
C130.0497 (5)0.33651 (13)−0.0272 (2)0.0668 (10)
O10.6224 (4)0.61903 (10)0.21954 (15)0.0611 (7)
H20.367500.713000.568100.0540*
H30.722400.757300.715400.0560*
H51.135900.616800.653000.0550*
H60.782800.572900.505600.0550*
H70.154500.628200.421100.0520*
H90.458300.474400.268700.0520*
H100.426200.389900.144200.0580*
H11−0.303300.41230−0.018400.0570*
H12−0.291400.496800.102800.0540*
H13A0.180000.34090−0.055500.1000*
H13B−0.109700.33600−0.094200.1000*
H13C0.072000.296200.017000.1000*
H1A0.551 (6)0.6046 (17)0.262 (2)0.0920*
H1B0.768 (6)0.5959 (17)0.242 (2)0.0920*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Cl10.0551 (4)0.0646 (4)0.0574 (3)−0.0114 (3)0.0116 (2)−0.0153 (3)
N10.0411 (10)0.0499 (12)0.0415 (8)−0.0024 (9)0.0133 (7)−0.0039 (8)
N20.0365 (10)0.0484 (12)0.0446 (8)−0.0022 (9)0.0135 (7)−0.0053 (8)
N30.0558 (12)0.0433 (12)0.0455 (9)−0.0060 (10)0.0216 (8)−0.0054 (8)
C10.0461 (13)0.0438 (13)0.0351 (9)−0.0015 (11)0.0173 (9)0.0023 (8)
C20.0453 (13)0.0457 (14)0.0446 (10)0.0042 (11)0.0182 (9)0.0017 (9)
C30.0577 (14)0.0395 (13)0.0434 (10)0.0004 (12)0.0212 (10)−0.0043 (9)
C40.0472 (13)0.0469 (14)0.0387 (10)−0.0069 (11)0.0154 (9)0.0011 (9)
C50.0431 (13)0.0481 (15)0.0456 (11)0.0046 (11)0.0167 (10)−0.0020 (9)
C60.0485 (14)0.0474 (14)0.0406 (10)0.0035 (11)0.0164 (9)−0.0065 (9)
C70.0422 (12)0.0473 (14)0.0429 (10)0.0003 (11)0.0191 (9)−0.0014 (9)
C80.0393 (12)0.0407 (13)0.0388 (9)−0.0004 (10)0.0158 (8)0.0028 (9)
C90.0374 (12)0.0458 (14)0.0428 (10)−0.0013 (10)0.0110 (9)0.0001 (9)
C100.0456 (13)0.0460 (14)0.0545 (11)0.0041 (11)0.0223 (10)0.0025 (10)
C110.0424 (13)0.0503 (15)0.0437 (10)−0.0070 (12)0.0118 (9)−0.0004 (10)
C120.0357 (12)0.0511 (15)0.0439 (10)−0.0021 (11)0.0120 (9)−0.0015 (9)
C130.084 (2)0.0570 (17)0.0615 (14)−0.0065 (15)0.0316 (14)−0.0174 (12)
O10.0514 (11)0.0661 (13)0.0668 (10)0.0032 (9)0.0250 (8)0.0088 (8)

Geometric parameters (Å, °)

Cl1—C41.742 (2)C8—C91.427 (3)
O1—H1B0.91 (4)C8—C121.428 (3)
O1—H1A0.84 (3)C9—C101.343 (3)
N1—N21.388 (2)C11—C121.342 (3)
N1—C71.281 (3)C2—H20.9300
N2—C81.327 (3)C3—H30.9300
N3—C101.356 (3)C5—H50.9300
N3—C111.355 (3)C6—H60.9300
N3—C131.475 (3)C7—H70.9300
C1—C21.398 (3)C9—H90.9300
C1—C71.462 (3)C10—H100.9300
C1—C61.388 (3)C11—H110.9300
C2—C31.379 (3)C12—H120.9300
C3—C41.376 (3)C13—H13C0.9600
C4—C51.380 (3)C13—H13A0.9600
C5—C61.373 (3)C13—H13B0.9600
Cl1···C2i3.521 (2)C11···C8iv3.516 (3)
Cl1···C7i3.572 (2)C11···O1iv3.378 (3)
Cl1···H10ii2.9800C13···C4xi3.598 (3)
O1···N2iii2.859 (3)C13···C3xi3.490 (4)
O1···C11iv3.378 (3)C3···H13Ax2.9800
O1···N13.089 (3)C7···H1Bvii3.07 (3)
O1···H13Biv2.9100C7···H1A2.91 (3)
O1···H3v2.5800C8···H1Bvii2.88 (4)
O1···H11iv2.4900C12···H1Bvii3.06 (3)
O1···H13Avi2.8100H1A···N12.26 (3)
N1···O13.089 (3)H1A···C72.91 (3)
N2···O1vii2.859 (3)H1B···H12iii2.5700
N1···H1A2.26 (3)H1B···N2iii1.95 (4)
N1···H62.6200H1B···C7iii3.07 (3)
N1···H92.4700H1B···C8iii2.88 (4)
N2···H1Bvii1.95 (4)H1B···C12iii3.06 (3)
C2···Cl1viii3.521 (2)H1B···H7iii2.5100
C3···C10ix3.576 (3)H2···H72.4300
C3···C13x3.490 (4)H3···O1xii2.5800
C4···C13x3.598 (3)H6···N12.6200
C4···C10ix3.582 (3)H7···H1Bvii2.5100
C5···C8ix3.473 (3)H7···H22.4300
C5···C9ix3.569 (3)H9···N12.4700
C6···C9ix3.464 (3)H10···H13A2.4800
C6···C8ix3.561 (3)H10···Cl1ii2.9800
C7···Cl1viii3.572 (2)H11···H13B2.3200
C8···C11iv3.516 (3)H11···O1iv2.4900
C8···C6ix3.561 (3)H12···H1Bvii2.5700
C8···C5ix3.473 (3)H13A···H102.4800
C9···C5ix3.569 (3)H13A···C3xi2.9800
C9···C6ix3.464 (3)H13A···O1vi2.8100
C10···C4ix3.582 (3)H13B···H112.3200
C10···C3ix3.576 (3)H13B···O1iv2.9100
H1A—O1—H1B106 (3)C1—C2—H2120.00
N2—N1—C7113.95 (19)C3—C2—H2120.00
N1—N2—C8112.75 (18)C4—C3—H3120.00
C10—N3—C13120.1 (2)C2—C3—H3120.00
C11—N3—C13121.1 (2)C4—C5—H5120.00
C10—N3—C11118.73 (19)C6—C5—H5120.00
C2—C1—C6118.52 (19)C5—C6—H6120.00
C6—C1—C7122.5 (2)C1—C6—H6120.00
C2—C1—C7119.0 (2)N1—C7—H7119.00
C1—C2—C3121.0 (2)C1—C7—H7119.00
C2—C3—C4119.0 (2)C10—C9—H9120.00
Cl1—C4—C5119.88 (18)C8—C9—H9120.00
C3—C4—C5121.1 (2)N3—C10—H10119.00
Cl1—C4—C3119.03 (17)C9—C10—H10119.00
C4—C5—C6119.7 (2)C12—C11—H11119.00
C1—C6—C5120.7 (2)N3—C11—H11119.00
N1—C7—C1121.9 (2)C8—C12—H12119.00
N2—C8—C12118.3 (2)C11—C12—H12119.00
C9—C8—C12114.43 (19)N3—C13—H13B109.00
N2—C8—C9127.27 (19)N3—C13—H13C109.00
C8—C9—C10120.8 (2)N3—C13—H13A109.00
N3—C10—C9122.7 (2)H13A—C13—H13C110.00
N3—C11—C12121.5 (2)H13B—C13—H13C110.00
C8—C12—C11122.0 (2)H13A—C13—H13B109.00
C7—N1—N2—C8−174.99 (18)C6—C1—C7—N1−10.1 (3)
N2—N1—C7—C1−179.43 (18)C1—C2—C3—C4−0.4 (3)
N1—N2—C8—C12−178.00 (18)C2—C3—C4—C50.0 (3)
N1—N2—C8—C92.6 (3)C2—C3—C4—Cl1179.29 (17)
C13—N3—C11—C12179.2 (2)C3—C4—C5—C60.2 (3)
C10—N3—C11—C12−0.6 (3)Cl1—C4—C5—C6−179.11 (17)
C11—N3—C10—C90.3 (3)C4—C5—C6—C10.1 (3)
C13—N3—C10—C9−179.5 (2)N2—C8—C9—C10179.3 (2)
C2—C1—C6—C5−0.5 (3)N2—C8—C12—C11−179.7 (2)
C7—C1—C2—C3180.0 (2)C9—C8—C12—C11−0.2 (3)
C7—C1—C6—C5−179.8 (2)C12—C8—C9—C10−0.2 (3)
C2—C1—C7—N1170.6 (2)C8—C9—C10—N30.1 (3)
C6—C1—C2—C30.7 (3)N3—C11—C12—C80.5 (3)

Symmetry codes: (i) x+1, −y+3/2, z+1/2; (ii) −x+2, −y+1, −z+1; (iii) x+1, y, z; (iv) −x, −y+1, −z; (v) x, −y+3/2, z−1/2; (vi) −x+1, −y+1, −z; (vii) x−1, y, z; (viii) x−1, −y+3/2, z−1/2; (ix) −x+1, −y+1, −z+1; (x) −x+1, y+1/2, −z+1/2; (xi) −x+1, y−1/2, −z+1/2; (xii) x, −y+3/2, z+1/2.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1A···N10.84 (3)2.26 (3)3.089 (3)173 (3)
O1—H1B···N2iii0.91 (4)1.95 (4)2.859 (3)174 (2)
C3—H3···O1xii0.932.583.421 (3)150
C11—H11···O1iv0.932.493.378 (3)159

Symmetry codes: (iii) x+1, y, z; (xii) x, −y+3/2, z+1/2; (iv) −x, −y+1, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ2782).

References

  • 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.
  • Alptüzün, V., Prinz, M., Hörr, V., Scheiber, J., Radacki, K., Fallarero, A., Vuorela, P., Engels, B., Braunschweig, H., Erciyas, E. & Holzgrabe, U. (2010). Bioorg. Med. Chem.18, 2049–2059. [PubMed]
  • Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst.32, 115–119.
  • Diao, Y.-P., Huang, S.-S., Kong, Y., Xia, M.-Y. & Meng, D.-L. (2008). Z. Kristallogr. New Cryst. Struct.223, 285–286.
  • Douglas, W. A., Fishinger, J. J., Gund, P., Haris, E. E., Olson, G., Patchett, A. A. & Ruyle, V. W. (1977). J. Med. Chem.20, 939–943. [PubMed]
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Odabaşoğlu, M., Albayrak, Ç., Büyükgüngör, O. & Goesmann, H. (2003). Acta Cryst. C59, o234–o236. [PubMed]
  • Pandey, J., Pal, R., Dwivedi, A. & Hajela, K. (2002). Arzneimittelforschung, 52, 39–44. [PubMed]
  • Pople, J. A. & Beveridge, D. L. (1970). In Approximate Molecular Orbital Theory New York: McGraw–Hill.
  • Salgın-Gökşen, U., Gökhan-Kelekçi, N., Göktaş, Ö., Köysal, Y., Kılıç, E., İşık, Ş., Aktay, G. & Özalp, M. (2007). Bioorg. Med. Chem.15, 5738–5751. [PubMed]
  • Savini, L., Chiasserini, L., Gaeta, A. & Pellerano, C. (2002). Bioorg. Med. Chem.10, 2193–2198. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Silva, G. A., Costa, L. M. M., Brito, F. C. F., Miranda, A. L. P., Barreiro, E. J. & Fraga, C. A. M. (2004). Bioorg. Med. Chem.12, 3149–3158. [PubMed]
  • Stoe & Cie (2002). X-AREA and X-RED32 Stoe & Cie, Darmstadt, Germany.
  • Vicini, P., Incerti, M., La Colla, P. & Loddo, R. (2009). Eur. J. Med. Chem.44, 1801–1807. [PubMed]

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