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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Methyl 2-(5-chloro-1-methyl-2-oxo-2,3-di­hydro-1H-indol-3-yl­idene)acetate

aDepartment of Physics, S.M.K. Fomra Institute of Technology, Thaiyur, Chennai 603 103, India, bIndustrial Chemistry Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India, and cDepartment of Physics, Presidency College (Autonomous), Chennai 600 005, India
*Correspondence e-mail: a_sp59@yahoo.in

(Received 10 April 2013; accepted 30 April 2013; online 11 May 2013)

The title compound, C12H10ClNO3, the indoline ring system is essentially planar, with a maximum deviation of 0.009 Å for the N atom. The indoline ring and acetate group are essentially coplanar, with a maximum deviation of 0.086 Å for the O atom. The mean plane through the methoxy­carbonyl­methyl group forms a dihedral angle of 3.68 (5)° with the plane of the indoline ring system. The mol­ecular structure is stabilized by an intra­molecular C—H⋯O hydrogen-bond inter­action. In the crystal, ππ stacking inter­actions [centroid–centroid distance = 3.7677 (8) Å] occur between benzene rings, forming a chain running along the c-axis direction.

Related literature

For the biological activity of indole derivatives, see: Chai et al. (2006[Chai, H., Zhao, C. & Gong, P. (2006). Bioorg. Med. Chem. 14, 911-917.]); Nieto et al. (2005[Nieto, M. J., Alovero, F. L., Manzo, R. H. & Mazzieri, M. R. (2005). Eur. J. Med. Chem. 40, 361-369.]); Singh et al. (2000[Singh, U. P., Sarma, B. K., Mishra, P. K. & Ray, A. B. (2000). Folia Microbiol. (Praha), 45, 173-176.]); Andreani et al. (2001[Andreani, A., Granaiola, M., Leoni, A., Locatelli, A., Morigi, R., Rambaldi, M., Giorgi, G., Salvini, L. & Garaliene, V. (2001). Anticancer Drug Des. 16, 167-174.]); Quetin-Leclercq (1994[Quetin-Leclercq, J. (1994). J. Pharm. Belg. 49, 181-192.]); Mukhopadhyay et al. (1981[Mukhopadhyay, S., Handy, G. A., Funayama, S. & Cordell, G. A. (1981). J. Nat. Prod. 44, 696-700.]); Taylor et al. (1999[Taylor, D. L., Ahmed, P. S., Chambers, P., Tyms, A. S., Bedard, J., Duchaine, J., Falardeau, G., Lavallee, J. F., Brown, W., Rando, R. F. & Bowlin, T. (1999). Antivir. Chem. Chemother. 10, 79-86.]). For closely related structures, see: Hu et al. (2011[Hu, F., Zheng, L., Zeng, X. C. & Li, K. P. (2011). Acta Cryst. E67, o742.]); Han & Luo (2012[Han, X.-L. & Luo, Y.-H. (2012). Acta Cryst. E68, o145.]); Deng (2011[Deng, Q. (2011). Acta Cryst. E67, o897.]). For puckering parameters, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]).

[Scheme 1]

Experimental

Crystal data
  • C12H10ClNO3

  • Mr = 251.66

  • Monoclinic, P 21 /c

  • a = 8.4709 (7) Å

  • b = 17.1658 (13) Å

  • c = 7.9481 (6) Å

  • β = 107.228 (4)°

  • V = 1103.88 (15) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.34 mm−1

  • T = 293 K

  • 0.30 × 0.25 × 0.20 mm

Data collection
  • Bruker SMART APEXII area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.903, Tmax = 0.934

  • 10447 measured reflections

  • 2815 independent reflections

  • 2410 reflections with I > 2σ(I)

  • Rint = 0.031

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.138

  • S = 1.13

  • 2815 reflections

  • 157 parameters

  • H-atom parameters constrained

  • Δρmax = 0.34 e Å−3

  • Δρmin = −0.21 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C6—H6⋯O2 0.93 2.30 3.0181 (17) 134

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, 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: ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Indole derivatives exhibit antihepatitis B virus (Chai et al., 2006) and antibacterial (Nieto et al., 2005) activities. Indole derivatives have been found to exhibit antibacterial, antifungal (Singh et al., 2000) and antitumour activities (Andreani et al., 2001). Some of the indole alkaloids extracted from plants possess interesting cytotoxic, antitumour or antiparasitic properties (Quetin-Leclercq, 1994; Mukhopadhyay et al., 1981). Pyrido[1,2-a]indole derivatives have been identified as potent inhibitors of human immunodeficiency virus type 1 (Taylor et al., 1999).

In the title compound, C12H10Cl1N1O3,Figure 1 the indole ring system [C1-C8/N1] is essentially co-planar, with maxmium deviations of -0.009 Å for N1 atom. The indole ring and acetate group systems are essentially co-planar, with maxmium deviations of 0.086 Å for O2 atom. The mean plane through the methyl 4-oxobutanoate(acetate) group forms a dihedral angle of 3.68 (5)° with the plane of the indole ring system.

The geometric parameters of the title molecule (Fig. 1) agree well with the reported similar structures (Han et al., 2012). The sum of the angles at N1 [359.98 (1)°] of the pyrrolidine rings are in accordance with sp2 hybridizations.The crystal structure is stabilized by intramolecular C-H···O hydrogen bond interaction and π -π stacking interactions [centroid–centroid distance = 3.7677 (8) Å] between benzene rings [Cg1–Cg1i (Cg1:C1–C6) (i):symmetry code: -x,1-y,1-z]

Related literature top

For the biological activity of indole derivatives, see: Chai et al. (2006); Nieto et al. (2005); Singh et al. (2000); Andreani et al. (2001); Quetin-Leclercq (1994); Mukhopadhyay et al. (1981); Taylor et al. (1999). For closely related structures, see: Hu et al. (2011); Han & Luo (2012); Deng (2011). For puckering parameters, see: Cremer & Pople (1975).

Experimental top

To a mixture of 1eq of (E)-methyl 2-(5-chloro-1-methyl-2-oxoindolin- 3-ylidene) acetate, 1eq of isatin and 1.5eq of sarcosine were dissolved in acetonitrile. This reaction mixture refluxed at 80°C for 8hours. Completion of reaction monitor by Thin layar chromatography. The reaction mixture was extracted with ethyl acetate and water. The product was dried and purified by coloumn chromatography using ethyl acetate and hexane (1:9) as an elutent to afford pure Dispiro oxindole. Yield (90%). Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.

Refinement top

All H atoms were fixed geometrically and allowed to ride on their parent C atoms, with C—H distances fixed in the range 0.93–0.97 Å with Uiso(H) = 1.5Ueq(C) for methyl H 1.2Ueq(C) for other H atoms. The positions of methyl hydrogens were optimized rotationally.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The structure of showing the atom-numbering scheme. The displacement ellipsoids are drawn at the 30% probability level.
Methyl 2-(5-chloro-1-methyl-2-oxo-2,3-dihydro-1H-indol-3-ylidene)acetate top
Crystal data top
C12H10ClNO3F(000) = 520
Mr = 251.66Dx = 1.514 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2857 reflections
a = 8.4709 (7) Åθ = 2.4–28.6°
b = 17.1658 (13) ŵ = 0.34 mm1
c = 7.9481 (6) ÅT = 293 K
β = 107.228 (4)°Block, colourless
V = 1103.88 (15) Å30.30 × 0.25 × 0.20 mm
Z = 4
Data collection top
Bruker SMART APEXII area-detector
diffractometer
2815 independent reflections
Radiation source: fine-focus sealed tube2410 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.031
ω and ϕ scansθmax = 28.6°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 1111
Tmin = 0.903, Tmax = 0.934k = 2323
10447 measured reflectionsl = 1010
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.138 w = 1/[σ2(Fo2) + (0.1P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.13(Δ/σ)max < 0.001
2815 reflectionsΔρmax = 0.34 e Å3
157 parametersΔρmin = 0.21 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.008 (3)
Crystal data top
C12H10ClNO3V = 1103.88 (15) Å3
Mr = 251.66Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.4709 (7) ŵ = 0.34 mm1
b = 17.1658 (13) ÅT = 293 K
c = 7.9481 (6) Å0.30 × 0.25 × 0.20 mm
β = 107.228 (4)°
Data collection top
Bruker SMART APEXII area-detector
diffractometer
2815 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
2410 reflections with I > 2σ(I)
Tmin = 0.903, Tmax = 0.934Rint = 0.031
10447 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.138H-atom parameters constrained
S = 1.13Δρmax = 0.34 e Å3
2815 reflectionsΔρmin = 0.21 e Å3
157 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
C10.18640 (15)0.52152 (8)0.41988 (16)0.0337 (3)
C20.22645 (18)0.44379 (9)0.44263 (18)0.0400 (3)
H20.32240.42830.52810.048*
C30.12324 (18)0.38846 (8)0.33765 (19)0.0396 (3)
H30.14870.33570.35140.047*
C40.01720 (16)0.41357 (7)0.21330 (17)0.0321 (3)
C50.05973 (15)0.49301 (7)0.18943 (15)0.0287 (3)
C60.04383 (15)0.54819 (7)0.29523 (15)0.0317 (3)
H60.01870.60100.28310.038*
C70.21570 (16)0.49743 (7)0.04971 (15)0.0306 (3)
C80.25984 (18)0.41402 (7)0.00755 (18)0.0344 (3)
C90.1339 (2)0.28462 (9)0.0829 (2)0.0509 (4)
H9A0.23320.26680.00220.076*
H9B0.12670.26250.19600.076*
H9C0.03980.26870.04760.076*
C100.31915 (15)0.55312 (8)0.03603 (16)0.0349 (3)
H100.41260.53630.12320.042*
C110.30207 (15)0.63753 (7)0.00835 (16)0.0341 (3)
C120.4227 (2)0.75770 (8)0.1167 (2)0.0499 (4)
H12A0.43110.77240.00310.075*
H12B0.51550.77820.20680.075*
H12C0.32220.77830.13140.075*
N10.13690 (14)0.36835 (6)0.09414 (14)0.0370 (3)
O10.38178 (14)0.39168 (7)0.12194 (15)0.0484 (3)
O20.19597 (13)0.67151 (6)0.10265 (16)0.0503 (3)
O30.42172 (12)0.67452 (6)0.12966 (13)0.0426 (3)
Cl10.31706 (4)0.58922 (2)0.55565 (4)0.04557 (17)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0283 (6)0.0363 (7)0.0319 (6)0.0017 (5)0.0015 (5)0.0008 (4)
C20.0347 (7)0.0386 (7)0.0406 (6)0.0058 (6)0.0016 (5)0.0059 (5)
C30.0409 (7)0.0302 (6)0.0437 (7)0.0054 (5)0.0065 (6)0.0047 (5)
C40.0331 (7)0.0284 (6)0.0340 (6)0.0013 (4)0.0084 (5)0.0007 (4)
C50.0277 (6)0.0265 (6)0.0306 (5)0.0001 (4)0.0065 (4)0.0003 (4)
C60.0285 (6)0.0303 (6)0.0324 (6)0.0003 (5)0.0031 (4)0.0001 (4)
C70.0289 (6)0.0299 (6)0.0307 (6)0.0030 (4)0.0052 (4)0.0027 (4)
C80.0372 (7)0.0298 (6)0.0346 (6)0.0055 (5)0.0084 (5)0.0045 (4)
C90.0618 (10)0.0273 (7)0.0595 (9)0.0019 (6)0.0116 (7)0.0034 (6)
C100.0298 (6)0.0344 (7)0.0346 (6)0.0026 (5)0.0003 (5)0.0025 (5)
C110.0298 (6)0.0345 (7)0.0332 (6)0.0040 (5)0.0021 (4)0.0012 (5)
C120.0546 (9)0.0351 (8)0.0501 (8)0.0081 (6)0.0003 (7)0.0075 (6)
N10.0406 (6)0.0272 (6)0.0399 (6)0.0034 (4)0.0068 (5)0.0045 (4)
O10.0443 (6)0.0404 (5)0.0503 (6)0.0094 (4)0.0018 (5)0.0099 (4)
O20.0423 (6)0.0347 (5)0.0547 (6)0.0022 (4)0.0151 (4)0.0065 (4)
O30.0408 (6)0.0336 (5)0.0406 (5)0.0029 (4)0.0074 (4)0.0021 (4)
Cl10.0370 (2)0.0450 (3)0.0434 (2)0.00716 (13)0.00546 (16)0.00314 (13)
Geometric parameters (Å, º) top
C1—C21.3753 (19)C8—O11.2183 (18)
C1—C61.3932 (16)C8—N11.3615 (18)
C1—Cl11.7415 (13)C9—N11.4408 (18)
C2—C31.389 (2)C9—H9A0.9600
C2—H20.9300C9—H9B0.9600
C3—C41.3717 (18)C9—H9C0.9600
C3—H30.9300C10—C111.4661 (19)
C4—N11.3995 (16)C10—H100.9300
C4—C51.4089 (17)C11—O21.2070 (16)
C5—C61.3917 (16)C11—O31.3346 (15)
C5—C71.4545 (17)C12—O31.4320 (16)
C6—H60.9300C12—H12A0.9600
C7—C101.3389 (19)C12—H12B0.9600
C7—C81.5153 (17)C12—H12C0.9600
C2—C1—C6122.71 (12)N1—C8—C7106.77 (11)
C2—C1—Cl1118.64 (10)N1—C9—H9A109.5
C6—C1—Cl1118.64 (10)N1—C9—H9B109.5
C1—C2—C3119.83 (13)H9A—C9—H9B109.5
C1—C2—H2120.1N1—C9—H9C109.5
C3—C2—H2120.1H9A—C9—H9C109.5
C4—C3—C2118.36 (12)H9B—C9—H9C109.5
C4—C3—H3120.8C7—C10—C11127.50 (11)
C2—C3—H3120.8C7—C10—H10116.3
C3—C4—N1127.82 (11)C11—C10—H10116.3
C3—C4—C5122.27 (12)O2—C11—O3122.67 (12)
N1—C4—C5109.92 (11)O2—C11—C10127.33 (11)
C6—C5—C4119.15 (11)O3—C11—C10109.98 (11)
C6—C5—C7133.90 (11)O3—C12—H12A109.5
C4—C5—C7106.94 (11)O3—C12—H12B109.5
C5—C6—C1117.68 (11)H12A—C12—H12B109.5
C5—C6—H6121.2O3—C12—H12C109.5
C1—C6—H6121.2H12A—C12—H12C109.5
C10—C7—C5137.34 (12)H12B—C12—H12C109.5
C10—C7—C8117.12 (12)C8—N1—C4110.84 (10)
C5—C7—C8105.52 (11)C8—N1—C9124.20 (12)
O1—C8—N1126.31 (12)C4—N1—C9124.94 (12)
O1—C8—C7126.92 (13)C11—O3—C12116.21 (11)
C6—C1—C2—C30.6 (2)C5—C7—C8—O1179.90 (14)
Cl1—C1—C2—C3179.16 (10)C10—C7—C8—N1178.76 (11)
C1—C2—C3—C40.1 (2)C5—C7—C8—N10.12 (13)
C2—C3—C4—N1179.68 (12)C5—C7—C10—C110.4 (2)
C2—C3—C4—C50.2 (2)C8—C7—C10—C11178.48 (12)
C3—C4—C5—C60.01 (19)C7—C10—C11—O24.1 (2)
N1—C4—C5—C6179.87 (10)C7—C10—C11—O3174.29 (13)
C3—C4—C5—C7179.19 (12)O1—C8—N1—C4179.33 (13)
N1—C4—C5—C70.93 (13)C7—C8—N1—C40.45 (14)
C4—C5—C6—C10.42 (17)O1—C8—N1—C90.9 (2)
C7—C5—C6—C1179.36 (11)C7—C8—N1—C9178.84 (12)
C2—C1—C6—C50.71 (19)C3—C4—N1—C8179.24 (13)
Cl1—C1—C6—C5179.32 (9)C5—C4—N1—C80.88 (14)
C6—C5—C7—C102.1 (2)C3—C4—N1—C90.9 (2)
C4—C5—C7—C10178.84 (15)C5—C4—N1—C9179.26 (13)
C6—C5—C7—C8179.66 (13)O2—C11—O3—C122.8 (2)
C4—C5—C7—C80.63 (12)C10—C11—O3—C12178.73 (12)
C10—C7—C8—O11.5 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···O20.932.303.0181 (17)134

Experimental details

Crystal data
Chemical formulaC12H10ClNO3
Mr251.66
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)8.4709 (7), 17.1658 (13), 7.9481 (6)
β (°) 107.228 (4)
V3)1103.88 (15)
Z4
Radiation typeMo Kα
µ (mm1)0.34
Crystal size (mm)0.30 × 0.25 × 0.20
Data collection
DiffractometerBruker SMART APEXII area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2008)
Tmin, Tmax0.903, 0.934
No. of measured, independent and
observed [I > 2σ(I)] reflections
10447, 2815, 2410
Rint0.031
(sin θ/λ)max1)0.673
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.138, 1.13
No. of reflections2815
No. of parameters157
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.34, 0.21

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···O20.932.303.0181 (17)134
 

Acknowledgements

The authors thank the TBI X-ray facility, CAS in Crystallography and BioPhysics, University of Madras, Chennai, India, for the data collection.

References

First citationAndreani, A., Granaiola, M., Leoni, A., Locatelli, A., Morigi, R., Rambaldi, M., Giorgi, G., Salvini, L. & Garaliene, V. (2001). Anticancer Drug Des. 16, 167–174.  Web of Science PubMed CAS Google Scholar
First citationBruker (2008). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationChai, H., Zhao, C. & Gong, P. (2006). Bioorg. Med. Chem. 14, 911–917.  Web of Science CrossRef PubMed CAS Google Scholar
First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.  CrossRef CAS Web of Science Google Scholar
First citationDeng, Q. (2011). Acta Cryst. E67, o897.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationHan, X.-L. & Luo, Y.-H. (2012). Acta Cryst. E68, o145.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationHu, F., Zheng, L., Zeng, X. C. & Li, K. P. (2011). Acta Cryst. E67, o742.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationMukhopadhyay, S., Handy, G. A., Funayama, S. & Cordell, G. A. (1981). J. Nat. Prod. 44, 696–700.  CrossRef CAS PubMed Web of Science Google Scholar
First citationNieto, M. J., Alovero, F. L., Manzo, R. H. & Mazzieri, M. R. (2005). Eur. J. Med. Chem. 40, 361–369.  Web of Science CrossRef PubMed CAS Google Scholar
First citationQuetin-Leclercq, J. (1994). J. Pharm. Belg. 49, 181–192.  CAS PubMed Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSingh, U. P., Sarma, B. K., Mishra, P. K. & Ray, A. B. (2000). Folia Microbiol. (Praha), 45, 173–176.  Web of Science CrossRef PubMed CAS Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationTaylor, D. L., Ahmed, P. S., Chambers, P., Tyms, A. S., Bedard, J., Duchaine, J., Falardeau, G., Lavallee, J. F., Brown, W., Rando, R. F. & Bowlin, T. (1999). Antivir. Chem. Chemother. 10, 79–86.  Web of Science PubMed CAS 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