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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Methyl 6′-amino-5′-cyano-2′-methyl-2-oxo­spiro­[indoline-3,4′-pyran]-3′-carboxyl­ate

aDepartment of Chemistry, Xuzhou Medical College, Xuzhou 221004, People's Republic of China
*Correspondence e-mail: songleizhu@126.com

(Received 17 November 2010; accepted 18 December 2010; online 24 December 2010)

In the mol­ecule of the title compound, C16H13N3O4, the atoms of the spiro pyran ring are nearly planar with a maximum deviation of 0.095 (2) Å. The indole and pyran rings are oriented at a dihedral angle of 87.3 (9)°. In the crystal, mol­ecules are linked by inter­molecular N—H⋯N and N—H⋯O hydrogen bonds.

Related literature

For the indole nucleus, see: Da-Silva et al. (2001[Da-Silva, J. F. M., Garden, S. J. & Pinto, A. C. (2001). J. Braz. Chem. Soc. 12, 273-324.]). Compounds carrying the indole moiety exhibit anti­bacterial and fungicidal activity, see: Joshi & Chand (1982[Joshi, K. C. & Chand, P. (1982). Pharmazie, 37, 1-12.]). Spiro­oxindole ring systems are found in a number of alkaloids like horsifiline, spiro­tryprostatin and elacomine, see: Abdel-Rahman et al. (2004[Abdel-Rahman, A. H., Keshk, E. M., Hanna, M. A. & El-Bady, Sh. M. (2004). Bioorg. Med. Chem. 12, 2483-2488.]). For our work on the preparation of heterocyclic compounds involving indole derivatives, see: Zhu et al. (2007[Zhu, S. L., Ji, S. J. & Zhang, Y. (2007). Tetrahedron, 63, 9365-9372.]).

[Scheme 1]

Experimental

Crystal data
  • C16H13N3O4

  • Mr = 311.29

  • Monoclinic, P 21 /c

  • a = 15.0260 (15) Å

  • b = 10.0614 (11) Å

  • c = 10.4862 (12) Å

  • β = 105.956 (1)°

  • V = 1524.3 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 298 K

  • 0.48 × 0.46 × 0.30 mm

Data collection
  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.954, Tmax = 0.971

  • 7311 measured reflections

  • 2686 independent reflections

  • 1868 reflections with I > 2σ(I)

  • Rint = 0.032

Refinement
  • R[F2 > 2σ(F2)] = 0.045

  • wR(F2) = 0.127

  • S = 1.04

  • 2686 reflections

  • 210 parameters

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.26 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯N3i 0.86 2.09 2.928 (3) 165
N2—H2A⋯O1ii 0.86 2.17 2.925 (2) 147
N2—H2B⋯O1iii 0.86 2.34 3.022 (2) 136
Symmetry codes: (i) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (ii) -x, -y+1, -z+1; (iii) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}].

Data collection: SMART (Bruker, 2004[Bruker (2004). SAINT and SMART. Bruker AXS Inc., Madinson, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2004[Bruker (2004). SAINT and SMART. Bruker AXS Inc., Madinson, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

The indole nucleus is the well known heterocycle (Da-Silva et al., 2001). Compounds carrying the indole moiety exhibit antibacterial and fungicidal activities (Joshi & Chand, 1982). Spirooxindole ring systems are found in a number of alkaloids like horsifiline, spirotryprostatin and elacomine (Abdel-Rahman et al., 2004). As a part of our programme devoted to the preparation of heterocyclic compounds involving indole derivatives (Zhu et al., 2007), we have synthesized a series of spirooxindoles via reactions of isatins together with malononitrile and methyl 3-oxobutanoate in water. We report herein the crystal structure of the title compound, (I), (Fig. 1). The new formed spiro pyran ring A (O2/C2/C10/C11/C14/C15) adopts nearly planar conformation. The indole system and pyran ring are oriented at a dihedral angle of 87.3 (9)°. In the crystal structure, the molecules are linked by intermolecular N—H···N and N—H···O hydrogen bonds, Table 1, (Fig. 2).

Related literature top

For the indole nucleus, see: Da-Silva et al. (2001). Compounds carrying the indole moiety exhibit antibacterial and fungicidal activity, see: Joshi & Chand (1982). Spirooxindole ring systems are found in a number of alkaloids like horsifiline, spirotryprostatin and elacomine, see: Abdel-Rahman et al., (2004). For our work on the preparation of heterocyclic compounds involving indole derivatives, see: Zhu et al., (2007).

Experimental top

Compound (I) was prepared by the reaction of isatin (1 mmol), malononitrile (1 mmol) and methyl 3-oxobutanoate (1 mmol) in water (5 ml). The reaction was catalyzed by TEBAC (triethylbenzylammonium chloride, 1 mmol). After stirring at 333 K for 5 h, the reaction mixture was cooled and washed with small amount of ethanol. The crude product was filtered and single crystals of the title compound were obtained from ethanol solution by slow evaporation at room temperature (yield; 82%, m.p. 535-536 K). Spectroscopic analysis: IR (KBr, ν , cm-1): 3458, 3362, 3217, 2212, 1729, 1628, 1464, 1376, 1284, 1210, 1057, 751, 676, 622. 1H NMR (400 MHz, DMSO-d6): 10.32 (s, 1H, NH), 7.21-7.25 (m, 3H, NH2 + ArH), 6.97-7.03 (m, 2H, ArH), 6.78 (d, J = 10.4 Hz, 1H, ArH), 3.76 (s, 3H, CH3), 2.25 (s, 3H, CH3).

Refinement top

H atoms were positioned geometrically, with N—H = 0.86 Å (for NH) and C—H = 0.93 and 0.96 Å for aromatic and methyl H, respectivly and constrained to ride on their parent atoms with Uiso(H) = xUeq(C,N), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 45% probability level.
[Figure 2] Fig. 2. A packing diagram of (I). Hydrogen bonds are shown as dashed lines.
Methyl 6'-amino-5'-cyano-2'-methyl-2-oxospiro[indoline-3,4'-pyran]-3'-carboxylate top
Crystal data top
C16H13N3O4F(000) = 648
Mr = 311.29Dx = 1.357 Mg m3
Monoclinic, P21/cMelting point = 535–536 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 15.0260 (15) ÅCell parameters from 2324 reflections
b = 10.0614 (11) Åθ = 2.5–25.2°
c = 10.4862 (12) ŵ = 0.10 mm1
β = 105.956 (1)°T = 298 K
V = 1524.3 (3) Å3Block, colorless
Z = 40.48 × 0.46 × 0.30 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
2686 independent reflections
Radiation source: fine-focus sealed tube1868 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
phi and ω scansθmax = 25.0°, θmin = 1.4°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 1717
Tmin = 0.954, Tmax = 0.971k = 1111
7311 measured reflectionsl = 1012
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)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.127H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0591P)2 + 0.418P]
where P = (Fo2 + 2Fc2)/3
2686 reflections(Δ/σ)max < 0.001
210 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.26 e Å3
Crystal data top
C16H13N3O4V = 1524.3 (3) Å3
Mr = 311.29Z = 4
Monoclinic, P21/cMo Kα radiation
a = 15.0260 (15) ŵ = 0.10 mm1
b = 10.0614 (11) ÅT = 298 K
c = 10.4862 (12) Å0.48 × 0.46 × 0.30 mm
β = 105.956 (1)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
2686 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1868 reflections with I > 2σ(I)
Tmin = 0.954, Tmax = 0.971Rint = 0.032
7311 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.127H-atom parameters constrained
S = 1.04Δρmax = 0.21 e Å3
2686 reflectionsΔρmin = 0.26 e Å3
210 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
N10.19598 (12)0.37685 (18)0.79711 (19)0.0494 (5)
H10.17690.31910.84410.059*
N20.04118 (12)0.68602 (18)0.34455 (18)0.0465 (5)
H2A0.02440.61670.29580.056*
H2B0.01960.76280.31590.056*
N30.10939 (15)0.3376 (2)0.4093 (2)0.0615 (6)
O10.08135 (10)0.53203 (14)0.77799 (14)0.0455 (4)
O20.11839 (10)0.79566 (13)0.52291 (15)0.0471 (4)
O30.31267 (10)0.62292 (17)0.91261 (15)0.0547 (4)
O40.35592 (12)0.82091 (18)0.85572 (19)0.0712 (6)
C10.15256 (14)0.4927 (2)0.7562 (2)0.0384 (5)
C20.20453 (13)0.56267 (19)0.66513 (19)0.0349 (5)
C30.28596 (13)0.4696 (2)0.6779 (2)0.0407 (5)
C40.27590 (15)0.3614 (2)0.7541 (2)0.0464 (6)
C50.33919 (17)0.2580 (2)0.7802 (3)0.0633 (7)
H50.33230.18570.83190.076*
C60.41318 (19)0.2672 (3)0.7260 (3)0.0727 (9)
H60.45670.19910.74130.087*
C70.42407 (17)0.3739 (3)0.6501 (3)0.0697 (8)
H70.47490.37740.61570.084*
C80.35978 (15)0.4768 (3)0.6242 (2)0.0528 (6)
H80.36650.54870.57200.063*
C90.30534 (14)0.7262 (2)0.8305 (2)0.0436 (5)
C100.23047 (13)0.7054 (2)0.7079 (2)0.0369 (5)
C110.18724 (14)0.8094 (2)0.6392 (2)0.0405 (5)
C120.19903 (19)0.9537 (2)0.6704 (3)0.0595 (7)
H12A0.23370.96500.76140.089*
H12B0.13930.99450.65620.089*
H12C0.23160.99470.61390.089*
C130.39267 (17)0.6183 (3)1.0257 (3)0.0714 (8)
H13A0.44660.64370.99930.107*
H13B0.40060.52961.06080.107*
H13C0.38430.67841.09250.107*
C140.14114 (13)0.56297 (19)0.52501 (19)0.0344 (5)
C150.10030 (13)0.67441 (19)0.4638 (2)0.0354 (5)
C160.12260 (14)0.4396 (2)0.4595 (2)0.0386 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0516 (11)0.0375 (11)0.0572 (13)0.0057 (9)0.0114 (9)0.0099 (9)
N20.0498 (11)0.0354 (10)0.0468 (12)0.0004 (8)0.0007 (9)0.0029 (8)
N30.0726 (14)0.0394 (12)0.0652 (14)0.0061 (10)0.0069 (11)0.0167 (10)
O10.0468 (9)0.0417 (9)0.0516 (10)0.0092 (7)0.0195 (7)0.0068 (7)
O20.0572 (9)0.0292 (8)0.0498 (10)0.0015 (7)0.0064 (8)0.0020 (7)
O30.0523 (9)0.0615 (11)0.0430 (10)0.0108 (8)0.0008 (8)0.0016 (8)
O40.0635 (11)0.0758 (13)0.0673 (12)0.0367 (10)0.0062 (9)0.0110 (10)
C10.0398 (11)0.0331 (12)0.0390 (12)0.0088 (9)0.0053 (9)0.0050 (9)
C20.0345 (10)0.0324 (11)0.0363 (11)0.0034 (8)0.0071 (9)0.0007 (9)
C30.0358 (11)0.0414 (13)0.0401 (12)0.0010 (9)0.0022 (9)0.0051 (10)
C40.0409 (12)0.0388 (12)0.0513 (14)0.0006 (10)0.0014 (10)0.0034 (10)
C50.0586 (15)0.0441 (15)0.0705 (18)0.0072 (12)0.0105 (14)0.0011 (12)
C60.0519 (15)0.0648 (19)0.086 (2)0.0207 (14)0.0061 (15)0.0161 (16)
C70.0434 (14)0.085 (2)0.076 (2)0.0112 (14)0.0082 (13)0.0167 (17)
C80.0405 (12)0.0635 (16)0.0523 (15)0.0028 (11)0.0091 (11)0.0049 (12)
C90.0409 (11)0.0503 (14)0.0415 (13)0.0119 (11)0.0148 (10)0.0103 (11)
C100.0387 (11)0.0376 (12)0.0365 (12)0.0106 (9)0.0140 (9)0.0054 (9)
C110.0456 (12)0.0337 (12)0.0444 (13)0.0115 (9)0.0162 (10)0.0070 (10)
C120.0803 (17)0.0336 (13)0.0654 (17)0.0135 (12)0.0217 (14)0.0105 (11)
C130.0563 (16)0.098 (2)0.0504 (16)0.0052 (15)0.0013 (13)0.0040 (15)
C140.0353 (10)0.0304 (11)0.0372 (12)0.0012 (8)0.0094 (9)0.0029 (9)
C150.0363 (11)0.0303 (11)0.0400 (13)0.0037 (8)0.0110 (10)0.0030 (9)
C160.0405 (11)0.0354 (13)0.0378 (12)0.0051 (9)0.0070 (9)0.0005 (10)
Geometric parameters (Å, º) top
N1—C11.347 (3)C4—C51.385 (3)
N1—C41.403 (3)C5—C61.384 (4)
N1—H10.8600C5—H50.9300
N2—C151.325 (3)C6—C71.372 (4)
N2—H2A0.8600C6—H60.9300
N2—H2B0.8600C7—C81.391 (3)
N3—C161.146 (3)C7—H70.9300
O1—C11.220 (2)C8—H80.9300
O2—C151.361 (2)C9—C101.472 (3)
O2—C111.372 (3)C10—C111.333 (3)
O3—C91.334 (3)C11—C121.489 (3)
O3—C131.439 (3)C12—H12A0.9600
O4—C91.202 (2)C12—H12B0.9600
C1—C21.558 (3)C12—H12C0.9600
C2—C141.515 (3)C13—H13A0.9600
C2—C31.517 (3)C13—H13B0.9600
C2—C101.523 (3)C13—H13C0.9600
C3—C81.377 (3)C14—C151.352 (3)
C3—C41.382 (3)C14—C161.409 (3)
C1—N1—C4112.07 (18)C3—C8—C7118.4 (2)
C1—N1—H1124.0C3—C8—H8120.8
C4—N1—H1124.0C7—C8—H8120.8
C15—N2—H2A120.0O4—C9—O3122.7 (2)
C15—N2—H2B120.0O4—C9—C10126.1 (2)
H2A—N2—H2B120.0O3—C9—C10111.16 (18)
C15—O2—C11120.13 (15)C11—C10—C9120.16 (19)
C9—O3—C13117.34 (19)C11—C10—C2122.26 (18)
O1—C1—N1126.4 (2)C9—C10—C2117.58 (18)
O1—C1—C2125.59 (19)C10—C11—O2122.51 (17)
N1—C1—C2107.80 (18)C10—C11—C12129.5 (2)
C14—C2—C3111.31 (16)O2—C11—C12107.98 (18)
C14—C2—C10108.97 (16)C11—C12—H12A109.5
C3—C2—C10114.92 (16)C11—C12—H12B109.5
C14—C2—C1107.93 (15)H12A—C12—H12B109.5
C3—C2—C1101.24 (16)C11—C12—H12C109.5
C10—C2—C1112.12 (16)H12A—C12—H12C109.5
C8—C3—C4120.4 (2)H12B—C12—H12C109.5
C8—C3—C2130.7 (2)O3—C13—H13A109.5
C4—C3—C2108.86 (18)O3—C13—H13B109.5
C3—C4—C5121.8 (2)H13A—C13—H13B109.5
C3—C4—N1109.75 (18)O3—C13—H13C109.5
C5—C4—N1128.4 (2)H13A—C13—H13C109.5
C6—C5—C4117.0 (3)H13B—C13—H13C109.5
C6—C5—H5121.5C15—C14—C16119.74 (18)
C4—C5—H5121.5C15—C14—C2122.94 (17)
C7—C6—C5121.8 (3)C16—C14—C2117.29 (17)
C7—C6—H6119.1N2—C15—C14128.29 (19)
C5—C6—H6119.1N2—C15—O2110.40 (17)
C6—C7—C8120.6 (3)C14—C15—O2121.30 (18)
C6—C7—H7119.7N3—C16—C14178.0 (2)
C8—C7—H7119.7
C4—N1—C1—O1179.4 (2)O3—C9—C10—C11153.2 (2)
C4—N1—C1—C24.4 (2)O4—C9—C10—C2152.4 (2)
O1—C1—C2—C1463.3 (2)O3—C9—C10—C226.1 (3)
N1—C1—C2—C14111.82 (18)C14—C2—C10—C1112.2 (3)
O1—C1—C2—C3179.74 (19)C3—C2—C10—C11137.8 (2)
N1—C1—C2—C35.2 (2)C1—C2—C10—C11107.3 (2)
O1—C1—C2—C1056.7 (3)C14—C2—C10—C9168.64 (16)
N1—C1—C2—C10128.16 (18)C3—C2—C10—C942.9 (2)
C14—C2—C3—C867.4 (3)C1—C2—C10—C971.9 (2)
C10—C2—C3—C857.0 (3)C9—C10—C11—O2178.62 (18)
C1—C2—C3—C8178.1 (2)C2—C10—C11—O22.2 (3)
C14—C2—C3—C4110.22 (19)C9—C10—C11—C123.6 (3)
C10—C2—C3—C4125.30 (19)C2—C10—C11—C12175.6 (2)
C1—C2—C3—C44.3 (2)C15—O2—C11—C109.0 (3)
C8—C3—C4—C50.6 (3)C15—O2—C11—C12172.84 (18)
C2—C3—C4—C5178.6 (2)C3—C2—C14—C15140.8 (2)
C8—C3—C4—N1179.97 (19)C10—C2—C14—C1513.0 (3)
C2—C3—C4—N12.0 (2)C1—C2—C14—C15108.9 (2)
C1—N1—C4—C31.6 (2)C3—C2—C14—C1641.4 (2)
C1—N1—C4—C5177.7 (2)C10—C2—C14—C16169.18 (17)
C3—C4—C5—C60.4 (3)C1—C2—C14—C1668.8 (2)
N1—C4—C5—C6179.6 (2)C16—C14—C15—N20.6 (3)
C4—C5—C6—C70.3 (4)C2—C14—C15—N2177.10 (18)
C5—C6—C7—C80.6 (4)C16—C14—C15—O2178.37 (18)
C4—C3—C8—C70.8 (3)C2—C14—C15—O23.9 (3)
C2—C3—C8—C7178.3 (2)C11—O2—C15—N2171.11 (16)
C6—C7—C8—C30.8 (4)C11—O2—C15—C148.0 (3)
C13—O3—C9—O49.1 (3)C15—C14—C16—N3176 (100)
C13—O3—C9—C10169.40 (19)C2—C14—C16—N36 (7)
O4—C9—C10—C1128.4 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···N3i0.862.092.928 (3)165
N2—H2A···O1ii0.862.172.925 (2)147
N2—H2B···O1iii0.862.343.022 (2)136
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+1, z+1; (iii) x, y+3/2, z1/2.

Experimental details

Crystal data
Chemical formulaC16H13N3O4
Mr311.29
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)15.0260 (15), 10.0614 (11), 10.4862 (12)
β (°) 105.956 (1)
V3)1524.3 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.48 × 0.46 × 0.30
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.954, 0.971
No. of measured, independent and
observed [I > 2σ(I)] reflections
7311, 2686, 1868
Rint0.032
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.127, 1.04
No. of reflections2686
No. of parameters210
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.26

Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···N3i0.862.092.928 (3)165
N2—H2A···O1ii0.862.172.925 (2)147
N2—H2B···O1iii0.862.343.022 (2)136
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+1, z+1; (iii) x, y+3/2, z1/2.
 

Acknowledgements

This work was partially supported by the Natural Science Foundation of Higher Education Institutions of Jiangsu Province (grant No. 09KJB150012) and the Special Presidential Foundation of Xuzhou Medical College (grant Nos. 09KJZ19 and 2010KJZ20) and the Open Foundation of the Key Laboratory of Cancer Biotherapy of Xuzhou Medical College (grant No. C0901).

References

First citationAbdel-Rahman, A. H., Keshk, E. M., Hanna, M. A. & El-Bady, Sh. M. (2004). Bioorg. Med. Chem. 12, 2483–2488.  Web of Science CrossRef PubMed CAS
First citationBruker (2004). SAINT and SMART. Bruker AXS Inc., Madinson, Wisconsin, USA.
First citationDa-Silva, J. F. M., Garden, S. J. & Pinto, A. C. (2001). J. Braz. Chem. Soc. 12, 273–324.  CAS
First citationJoshi, K. C. & Chand, P. (1982). Pharmazie, 37, 1–12.  CAS PubMed Web of Science
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationZhu, S. L., Ji, S. J. & Zhang, Y. (2007). Tetrahedron, 63, 9365–9372.  Web of Science CSD CrossRef CAS

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