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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

4-[2-(4-Chloro­phen­yl)hydrazinyl­­idene]-3-methyl-5-oxo-4,5-di­hydro-1H-pyrazole-1-carbo­thio­amide

aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bDepartment of Studies in Chemistry, Mangalore University, Mangalagangothri 574 199, Karnataka, India
*Correspondence e-mail: hkfun@usm.my

(Received 12 September 2011; accepted 20 September 2011; online 30 September 2011)

In the title mol­ecule, C11H10ClN5OS, an intra­molecular N—H⋯O hydrogen forms an S(6) ring motif. The dihedral angle between the pyrazole ring and the benzene ring is 3.77 (8)°. In the crystal, mol­ecules are linked by N—H⋯S and N—H⋯O hydrogen bonds into layers parallel to the bc plane.

Related literature

For the biological activity and pharmacological properties of pyrazole derivatives, see: Rai et al. (2008[Rai, N. S., Kalluraya, B., Lingappa, B., Shenoy, S. & Puranic, V. G. (2008). Eur. J. Med. Chem. 43, 1715-1720.]); Girisha et al. (2010[Girisha, K. S., Kalluraya, B., Narayana, V. & Padmashree (2010). Eur. J. Med. Chem. 45, 4640-4644.]); Isloor et al. (2009[Isloor, A. M., Kalluraya, B. & Shetty, P. (2009). Eur. J. Med. Chem. 44, 3784-3787.]). For standard bond-length data, 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.]). For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C11H10ClN5OS

  • Mr = 295.75

  • Monoclinic, C 2/c

  • a = 25.0899 (17) Å

  • b = 11.6075 (9) Å

  • c = 9.0806 (6) Å

  • β = 99.516 (1)°

  • V = 2608.2 (3) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.45 mm−1

  • T = 296 K

  • 0.48 × 0.33 × 0.17 mm

Data collection
  • Bruker SMART APEXII DUO CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.812, Tmax = 0.927

  • 22139 measured reflections

  • 3827 independent reflections

  • 3125 reflections with I > 2σ(I)

  • Rint = 0.024

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.120

  • S = 1.04

  • 3827 reflections

  • 185 parameters

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

  • Δρmax = 0.36 e Å−3

  • Δρmin = −0.49 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N4—H1N4⋯O1 0.914 (18) 2.114 (19) 2.7903 (16) 129.9 (16)
N5—H1N5⋯S1i 0.89 (2) 2.76 (2) 3.5239 (13) 144.5 (16)
N5—H2N5⋯O1ii 0.91 (2) 2.00 (2) 2.9124 (15) 177.0 (19)
Symmetry codes: (i) [x, -y+1, z+{\script{1\over 2}}]; (ii) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2009[Bruker (2009). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Pyrazole derivatives are well established in the literatures as important biologically active heterocyclic compounds (Rai et al., 2008). These derivatives are the subject of many research studies due to their widespread pharmacological properties such as anti-inflammatory (Girisha et al., 2010), antipyretic, antimicrobial (Isloor et al., 2009), and antiviral activities. The widely prescribed anti-inflammatory pyrazole derivatives, celecoxib and deracoxib, are selective COX-2 inhibitors with reduced ulcerogenic side effects. The synthetic route followed for obtaining the title compound involves the diazotization of substituted anilines to give the diazonium salts followed by coupling with ethyl acetoacetate in the presence of sodium acetate to give corresponding oxobutanoate which on further reaction with thiosemicarbazide in acetic acid gave the required thioamides.

The molecular structure is shown in Fig. 1. An intramolecular N4—H1N4···O1 hydrogen bond (Table 1) stabilizes the molecular structure and forms an S(6) ring motif (Bernstein et al., 1995). The dihedral angle between the 4,5-dihydro-1H-pyrazole (N1/N2/C1–C3) ring and the phenyl (C4–C9) ring is 3.77 (8)°. Bond lengths (Allen et al., 1987) and angles are within normal ranges.

The crystal packing is shown in Fig. 2. The molecules are linked by intermolecular N5—H1N5···S1i and N5—H2N5···O1ii hydrogen bonds (Table 1) into layers parallel to bc plane.

Related literature top

For the biological activity and pharmacological properties of pyrazole derivatives, see: Rai et al. (2008); Girisha et al. (2010); Isloor et al. (2009). For standard bond-length data, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Experimental top

To a solution of ethyl-2-[(4-chlorophenyl)hydrazono]-3-oxobutanoate (0.01 mol) dissolved in glacial acetic acid (20 ml), a solution of thiosemicarbazide (0.02 mol) in glacial acetic acid (25 ml) was added and the mixture was refluxed for 4 h. It was cooled and allowed to stand overnight. The solid product that separated out was filtered and dried. It was then recrystallized from ethanol. Crystals suitable for X-ray analysis were obtained from 1:2 mixtures of DMF and ethanol by slow evaporation.

Refinement top

N-bound H atoms was located from the difference map and refined freely, [N–H = 0.89 (2)–0.912 (18) Å]. The remaining H atoms were positioned geometrically [C–H = 0.93 or 0.96 Å] and refined using a riding model with Uiso(H) = 1.2 or 1.5 Ueq(C). A rotating group model was applied to the methyl group.

Structure description top

Pyrazole derivatives are well established in the literatures as important biologically active heterocyclic compounds (Rai et al., 2008). These derivatives are the subject of many research studies due to their widespread pharmacological properties such as anti-inflammatory (Girisha et al., 2010), antipyretic, antimicrobial (Isloor et al., 2009), and antiviral activities. The widely prescribed anti-inflammatory pyrazole derivatives, celecoxib and deracoxib, are selective COX-2 inhibitors with reduced ulcerogenic side effects. The synthetic route followed for obtaining the title compound involves the diazotization of substituted anilines to give the diazonium salts followed by coupling with ethyl acetoacetate in the presence of sodium acetate to give corresponding oxobutanoate which on further reaction with thiosemicarbazide in acetic acid gave the required thioamides.

The molecular structure is shown in Fig. 1. An intramolecular N4—H1N4···O1 hydrogen bond (Table 1) stabilizes the molecular structure and forms an S(6) ring motif (Bernstein et al., 1995). The dihedral angle between the 4,5-dihydro-1H-pyrazole (N1/N2/C1–C3) ring and the phenyl (C4–C9) ring is 3.77 (8)°. Bond lengths (Allen et al., 1987) and angles are within normal ranges.

The crystal packing is shown in Fig. 2. The molecules are linked by intermolecular N5—H1N5···S1i and N5—H2N5···O1ii hydrogen bonds (Table 1) into layers parallel to bc plane.

For the biological activity and pharmacological properties of pyrazole derivatives, see: Rai et al. (2008); Girisha et al. (2010); Isloor et al. (2009). For standard bond-length data, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); 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 30% probability displacement ellipsoids. The dashed line indicates an intramolecular bond.
[Figure 2] Fig. 2. The crystal packing of the title compound. The dashed lines represent hydrogen bonds.
4-[2-(4-Chlorophenyl)hydrazinylidene]-3-methyl-5-oxo-4,5-dihydro-1H- pyrazole-1-carbothioamide top
Crystal data top
C11H10ClN5OSF(000) = 1216
Mr = 295.75Dx = 1.506 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 9651 reflections
a = 25.0899 (17) Åθ = 2.9–29.9°
b = 11.6075 (9) ŵ = 0.45 mm1
c = 9.0806 (6) ÅT = 296 K
β = 99.516 (1)°Block, orange
V = 2608.2 (3) Å30.48 × 0.33 × 0.17 mm
Z = 8
Data collection top
Bruker SMART APEXII DUO CCD area-detector
diffractometer
3827 independent reflections
Radiation source: fine-focus sealed tube3125 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
φ and ω scansθmax = 30.1°, θmin = 1.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 3535
Tmin = 0.812, Tmax = 0.927k = 1616
22139 measured reflectionsl = 1212
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)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.120H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0678P)2 + 1.0988P]
where P = (Fo2 + 2Fc2)/3
3827 reflections(Δ/σ)max = 0.003
185 parametersΔρmax = 0.36 e Å3
0 restraintsΔρmin = 0.49 e Å3
Crystal data top
C11H10ClN5OSV = 2608.2 (3) Å3
Mr = 295.75Z = 8
Monoclinic, C2/cMo Kα radiation
a = 25.0899 (17) ŵ = 0.45 mm1
b = 11.6075 (9) ÅT = 296 K
c = 9.0806 (6) Å0.48 × 0.33 × 0.17 mm
β = 99.516 (1)°
Data collection top
Bruker SMART APEXII DUO CCD area-detector
diffractometer
3827 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
3125 reflections with I > 2σ(I)
Tmin = 0.812, Tmax = 0.927Rint = 0.024
22139 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.120H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.36 e Å3
3827 reflectionsΔρmin = 0.49 e Å3
185 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
S10.247690 (16)0.67094 (3)0.16327 (4)0.04930 (13)
Cl10.47498 (2)1.36700 (4)0.93948 (6)0.07500 (18)
O10.29887 (5)0.85770 (9)0.39231 (11)0.0481 (3)
N10.30587 (5)0.65709 (9)0.43842 (11)0.0376 (2)
N20.33273 (5)0.58737 (10)0.55643 (12)0.0456 (3)
N30.37848 (5)0.86126 (10)0.67837 (13)0.0431 (3)
N40.36803 (5)0.96471 (10)0.62440 (13)0.0424 (3)
N50.26388 (6)0.49214 (11)0.34633 (13)0.0489 (3)
C10.35437 (5)0.77370 (11)0.60545 (14)0.0397 (3)
C20.31655 (5)0.77385 (11)0.46481 (13)0.0358 (2)
C30.36083 (7)0.65570 (12)0.65135 (16)0.0471 (3)
C40.39475 (5)1.05982 (11)0.69841 (14)0.0389 (3)
C50.43223 (6)1.04497 (13)0.82750 (17)0.0504 (3)
H5A0.44080.97140.86470.060*
C60.45677 (7)1.14060 (14)0.90042 (19)0.0557 (4)
H6A0.48181.13170.98750.067*
C70.44409 (6)1.24900 (13)0.84375 (17)0.0479 (3)
C80.40700 (6)1.26442 (13)0.71486 (17)0.0510 (3)
H8A0.39881.33800.67740.061*
C90.38221 (6)1.16883 (12)0.64217 (17)0.0473 (3)
H9A0.35711.17800.55540.057*
C100.27250 (5)0.60195 (11)0.32065 (13)0.0374 (3)
C110.39486 (10)0.61297 (16)0.7902 (2)0.0773 (6)
H11A0.38450.53560.80970.116*
H11B0.38990.66160.87240.116*
H11C0.43220.61410.77820.116*
H1N40.3454 (7)0.9766 (17)0.536 (2)0.052 (5)*
H1N50.2758 (8)0.4615 (18)0.435 (2)0.060 (5)*
H2N50.2431 (8)0.4515 (19)0.272 (2)0.064 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0633 (2)0.0481 (2)0.03108 (17)0.00100 (15)0.00811 (14)0.00135 (12)
Cl10.0730 (3)0.0509 (2)0.0885 (4)0.00312 (19)0.0239 (2)0.0250 (2)
O10.0625 (6)0.0356 (5)0.0409 (5)0.0050 (4)0.0071 (4)0.0029 (4)
N10.0460 (6)0.0343 (5)0.0287 (5)0.0019 (4)0.0046 (4)0.0015 (4)
N20.0584 (7)0.0352 (5)0.0371 (5)0.0016 (5)0.0104 (5)0.0047 (4)
N30.0486 (6)0.0387 (5)0.0392 (5)0.0032 (5)0.0011 (5)0.0034 (4)
N40.0485 (6)0.0366 (5)0.0384 (5)0.0032 (4)0.0034 (5)0.0035 (4)
N50.0674 (8)0.0416 (6)0.0326 (5)0.0111 (6)0.0067 (5)0.0016 (5)
C10.0455 (7)0.0359 (6)0.0343 (5)0.0020 (5)0.0035 (5)0.0011 (5)
C20.0411 (6)0.0342 (6)0.0306 (5)0.0010 (5)0.0019 (4)0.0003 (4)
C30.0566 (8)0.0391 (6)0.0389 (6)0.0021 (6)0.0118 (6)0.0031 (5)
C40.0398 (6)0.0382 (6)0.0374 (6)0.0020 (5)0.0020 (5)0.0059 (5)
C50.0521 (8)0.0413 (7)0.0515 (8)0.0038 (6)0.0099 (6)0.0034 (6)
C60.0529 (8)0.0523 (8)0.0531 (8)0.0040 (7)0.0175 (7)0.0083 (7)
C70.0438 (7)0.0429 (7)0.0529 (7)0.0011 (5)0.0037 (6)0.0127 (6)
C80.0552 (8)0.0379 (7)0.0547 (8)0.0012 (6)0.0060 (6)0.0025 (6)
C90.0518 (8)0.0412 (7)0.0431 (7)0.0022 (6)0.0087 (6)0.0011 (5)
C100.0414 (6)0.0404 (6)0.0286 (5)0.0022 (5)0.0008 (4)0.0036 (4)
C110.1033 (15)0.0516 (9)0.0583 (10)0.0039 (9)0.0415 (10)0.0100 (8)
Geometric parameters (Å, º) top
S1—C101.6664 (13)C1—C21.4597 (17)
Cl1—C71.7347 (14)C3—C111.486 (2)
O1—C21.2169 (16)C4—C91.3813 (19)
N1—C21.3945 (16)C4—C51.3870 (19)
N1—C101.3995 (15)C5—C61.384 (2)
N1—N21.4207 (15)C5—H5A0.9300
N2—C31.2916 (18)C6—C71.377 (2)
N3—C11.3057 (17)C6—H6A0.9300
N3—N41.3070 (16)C7—C81.381 (2)
N4—C41.4039 (16)C8—C91.385 (2)
N4—H1N40.912 (18)C8—H8A0.9300
N5—C101.3200 (18)C9—H9A0.9300
N5—H1N50.89 (2)C11—H11A0.9600
N5—H2N50.91 (2)C11—H11B0.9600
C1—C31.4331 (19)C11—H11C0.9600
C2—N1—C10130.50 (11)C6—C5—H5A120.3
C2—N1—N2111.74 (10)C4—C5—H5A120.3
C10—N1—N2117.72 (10)C7—C6—C5119.82 (14)
C3—N2—N1106.99 (11)C7—C6—H6A120.1
C1—N3—N4118.53 (12)C5—C6—H6A120.1
N3—N4—C4119.51 (11)C6—C7—C8121.12 (13)
N3—N4—H1N4121.7 (12)C6—C7—Cl1118.55 (11)
C4—N4—H1N4118.7 (12)C8—C7—Cl1120.33 (12)
C10—N5—H1N5120.4 (13)C7—C8—C9119.12 (14)
C10—N5—H2N5117.2 (13)C7—C8—H8A120.4
H1N5—N5—H2N5122.2 (19)C9—C8—H8A120.4
N3—C1—C3125.15 (12)C4—C9—C8120.05 (13)
N3—C1—C2128.49 (12)C4—C9—H9A120.0
C3—C1—C2106.35 (11)C8—C9—H9A120.0
O1—C2—N1129.93 (12)N5—C10—N1113.67 (11)
O1—C2—C1126.90 (12)N5—C10—S1124.52 (10)
N1—C2—C1103.17 (10)N1—C10—S1121.81 (10)
N2—C3—C1111.70 (12)C3—C11—H11A109.5
N2—C3—C11122.34 (14)C3—C11—H11B109.5
C1—C3—C11125.96 (13)H11A—C11—H11B109.5
C9—C4—C5120.50 (12)C3—C11—H11C109.5
C9—C4—N4118.80 (12)H11A—C11—H11C109.5
C5—C4—N4120.68 (12)H11B—C11—H11C109.5
C6—C5—C4119.38 (14)
C2—N1—N2—C32.16 (17)C2—C1—C3—C11178.78 (18)
C10—N1—N2—C3179.95 (13)N3—N4—C4—C9178.31 (14)
C1—N3—N4—C4178.03 (13)N3—N4—C4—C50.3 (2)
N4—N3—C1—C3178.84 (15)C9—C4—C5—C60.5 (2)
N4—N3—C1—C21.4 (2)N4—C4—C5—C6178.13 (14)
C10—N1—C2—O11.0 (2)C4—C5—C6—C70.5 (3)
N2—N1—C2—O1176.43 (14)C5—C6—C7—C80.2 (3)
C10—N1—C2—C1179.99 (13)C5—C6—C7—Cl1179.16 (14)
N2—N1—C2—C12.57 (15)C6—C7—C8—C90.1 (3)
N3—C1—C2—O13.2 (2)Cl1—C7—C8—C9178.82 (13)
C3—C1—C2—O1177.00 (14)C5—C4—C9—C80.2 (2)
N3—C1—C2—N1177.80 (14)N4—C4—C9—C8178.48 (14)
C3—C1—C2—N12.04 (15)C7—C8—C9—C40.2 (3)
N1—N2—C3—C10.72 (19)C2—N1—C10—N5167.44 (14)
N1—N2—C3—C11179.63 (18)N2—N1—C10—N59.85 (18)
N3—C1—C3—N2178.98 (14)C2—N1—C10—S113.6 (2)
C2—C1—C3—N20.86 (19)N2—N1—C10—S1169.10 (10)
N3—C1—C3—C111.4 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N4—H1N4···O10.914 (18)2.114 (19)2.7903 (16)129.9 (16)
N5—H1N5···S1i0.89 (2)2.76 (2)3.5239 (13)144.5 (16)
N5—H2N5···O1ii0.91 (2)2.00 (2)2.9124 (15)177.0 (19)
Symmetry codes: (i) x, y+1, z+1/2; (ii) x+1/2, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC11H10ClN5OS
Mr295.75
Crystal system, space groupMonoclinic, C2/c
Temperature (K)296
a, b, c (Å)25.0899 (17), 11.6075 (9), 9.0806 (6)
β (°) 99.516 (1)
V3)2608.2 (3)
Z8
Radiation typeMo Kα
µ (mm1)0.45
Crystal size (mm)0.48 × 0.33 × 0.17
Data collection
DiffractometerBruker SMART APEXII DUO CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2009)
Tmin, Tmax0.812, 0.927
No. of measured, independent and
observed [I > 2σ(I)] reflections
22139, 3827, 3125
Rint0.024
(sin θ/λ)max1)0.705
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.120, 1.04
No. of reflections3827
No. of parameters185
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.36, 0.49

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N4—H1N4···O10.914 (18)2.114 (19)2.7903 (16)129.9 (16)
N5—H1N5···S1i0.89 (2)2.76 (2)3.5239 (13)144.5 (16)
N5—H2N5···O1ii0.91 (2)2.00 (2)2.9124 (15)177.0 (19)
Symmetry codes: (i) x, y+1, z+1/2; (ii) x+1/2, y1/2, z+1/2.
 

Footnotes

Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

The authors thank Universiti Sains Malaysia (USM) for the Research University Grant (1001/PFIZIK/811160). SA also thanks the Malaysian Government and USM for the Academic Staff Training Scheme (ASTS) award.

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.  CSD CrossRef Web of Science Google Scholar
First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2009). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationGirisha, K. S., Kalluraya, B., Narayana, V. & Padmashree (2010). Eur. J. Med. Chem. 45, 4640–4644.  Google Scholar
First citationIsloor, A. M., Kalluraya, B. & Shetty, P. (2009). Eur. J. Med. Chem. 44, 3784–3787.  Web of Science CrossRef PubMed CAS Google Scholar
First citationRai, N. S., Kalluraya, B., Lingappa, B., Shenoy, S. & Puranic, V. G. (2008). Eur. J. Med. Chem. 43, 1715–1720.  Web of Science PubMed Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds