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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Bostrycin

aState Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, People's Republic of China, and bCollege of Pharmaceutical Sicence, Zhejiang University, People's Republic of China
*Correspondence e-mail: fuchenglin@zju.edu.cn

(Received 6 September 2008; accepted 6 October 2008; online 31 October 2008)

The title compound, C16H16O8, is a potent nonspecific phyto­toxin. The crystal structure is the average of two tauto­mers, 5,6,7,9,10-penta­hydr­oxy-2-meth­oxy-7-methyl-1,4,5,6,7,8-hexa­hydro­anthracene-1,4-dione and 1,4,5,6,7-pentahydr­oxy-2-meth­­oxy-7-methyl-5,6,7,8,9,10-hexa­hydro­anthracene-9,10-di­one. The cyclo­hexene rings in both tautomers display a half-chair conformation. An extensive O—H⋯O hydrogen-bonding network is present in the crystal structure.

Related literature

For general background, see: Charudattan & Rao (1982[Charudattan, R. & Rao, K. V. (1982). Appl. Environ. Microbiol. 43, 846-849.]); van Eijk (1975[Eijk, G. W. van (1975). Cell. Mol. Life Sci. 31, 783-784.]). For a related structure, see: Kelly & Saha (1985[Kelly, T. & Saha, J. K. (1985). J. Org. Chem. 50, 3679-3685.]).

[Scheme 1]

Experimental

Crystal data
  • C16H16O8

  • Mr = 336.29

  • Monoclinic, P 21

  • a = 8.280 (2) Å

  • b = 6.644 (2) Å

  • c = 13.1535 (12) Å

  • β = 102.12 (2)°

  • V = 707.5 (3) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.13 mm−1

  • T = 293 (2) K

  • 0.30 × 0.20 × 0.08 mm

Data collection
  • Rigaku R-AXIS RAPID IP diffractometer

  • Absorption correction: multi-scan (ABSCOR; Higashi, 1995[Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.953, Tmax = 0.990

  • 6151 measured reflections

  • 1517 independent reflections

  • 1282 reflections with I > 2σ(I)

  • Rint = 0.025

Refinement
  • R[F2 > 2σ(F2)] = 0.035

  • wR(F2) = 0.105

  • S = 1.08

  • 1517 reflections

  • 220 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.24 e Å−3

  • Δρmin = −0.19 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1A⋯O3i 0.85 2.55 3.229 (3) 137
O3—H3A⋯O8ii 0.84 2.40 2.808 (3) 111
O4—H4A⋯O8ii 0.90 2.54 3.223 (3) 132
O5—H5A⋯O4 0.92 1.85 2.687 (3) 152
O6—H6A⋯O7iii 0.97 1.92 2.821 (3) 154
O7—H7A⋯O1iv 0.90 2.11 2.966 (3) 159
O7—H7A⋯O2iv 0.90 2.40 3.066 (3) 131
Symmetry codes: (i) x+1, y, z; (ii) x-1, y, z; (iii) [-x+1, y-{\script{1\over 2}}, -z+2]; (iv) [-x+1, y+{\script{1\over 2}}, -z+1].

Data collection: PROCESS-AUTO (Rigaku, 1998[Rigaku (1998). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan.]); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002[Rigaku/MSC (2002). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA.]); 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 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Bostrycin, a nonspecific phytotoxin, was identified as a metabolite of the fungus Arthrinium phaeospermum in 1975 (van Eijk, 1975; Charudattan & Rao, 1982). It is active against Bacillus subtilis but inactive against the fungus Geotrichum candidum (Charudattan & Rao, 1982). We report here the crystal structure of the title compound.

The crystal structure of the title compound is the average structure of two tautomers, 5,6,7,9,10-pentahydroxy-2-methoxy-7-methyl-1,4,5,6,7,8-hexahydroanthracene- 1,4-dione (I) and 1,4,5,6,7-pentahydroxy-2-methoxy-7-methyl-5,6,7,8,9,10-hexahydroanthracene- 9,10-dione (II). The molecular structures of the two tautomers are shown in Fig. 1 and Fig. 2, respectively. Both of tautomer molecules contains three six-membered rings, among which the C9-containing ring displays a half-chair conformation. Within the molecule the carbonyl group is hydrogen bonded to the neighboring hydroxyl group(s). The bond distances and angles agree with those found in a derivative of bostrycin, bostrycin acetonide (Kelly & Saha, 1985). The extensive O—H···O hydrogen bonding network helps to stabilize the crystal structure (Table 1).

Related literature top

For general background, see: Charudattan & Rao (1982); van Eijk (1975). For a related structure, see: Kelly & Saha (1985).

Experimental top

For morphological identification (Arthrinium sp. (CGMCC 2082), a fungi from Polygonum hydropiper L.) cultures were grown on OA, PDA, and SNA media for 7–14 days at room temperature (293 K) under ambient daylight. Microscopic observations and measurements were made from slides mounted in water. For metabolite production, the strains were inoculated onto PDA media and incubated for 10 days at 298 K in the dark. Selected strains were also cultivated in liquid media placed in a rotary shaker at 120 rpm for 7 days at 298 K in the dark. After cultivation, the bottles were stored at 253 K until extraction.

Liquid cultures were extracted with trichloromethane. The trichloromethane phase was filtered and evaporated in vacuo. Samples were then redissolved in trichloromethane, then filtered to remove solid. The trichloromethane solution was evaporated in vacuo. The single crystals were obtained from an ethanol solution.

Refinement top

Hydroxyl H atoms were located in a difference Fourier map and refined as riding in as-found relative positions with Uiso(H) = 1.5Ueq(O). Methyl H atoms were placed in calculated positions with C—H = 0.96 Å and torsion angles were refined to fit the electron density, Uiso(H) = 1.5Ueq(C). Other H atoms were placed in calculated positions with C—H = 0.93 (aromatic), 0.97 (methylene) or 0.98 Å (methine), and refined in riding mode with Uiso(H) = 1.2Ueq(C). In the absence of significant anomalous scattering effects, Friedel pairs were merged; the absolute configuration was not determined.

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with 50% probability displacement ellipsoids (arbitrary spheres for H atoms), dashed line indicates hydrogen bonding.
[Figure 2] Fig. 2. The molecular structure of (II) with 50% probability displacement ellipsoids (arbitrary spheres for H atoms), dashed line indicates hydrogen bonding.
5,6,7,9,10-pentahydroxy-2-methoxy-7-methyl-1,4,5,6,7,8-hexahydroanthracene- 1,4-dione–1,4,5,6,7-pentahydroxy-2-methoxy-7-methyl-5,6,7,8,9,10- hexahydroanthracene-9,10-dione top
Crystal data top
C16H16O8F(000) = 352
Mr = 336.29Dx = 1.579 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71069 Å
Hall symbol: P 2ybCell parameters from 5814 reflections
a = 8.280 (2) Åθ = 6.1–54.9°
b = 6.644 (2) ŵ = 0.13 mm1
c = 13.1535 (12) ÅT = 293 K
β = 102.12 (2)°Chunk, red
V = 707.5 (3) Å30.30 × 0.20 × 0.08 mm
Z = 2
Data collection top
Rigaku R-AXIS RAPID IP
diffractometer
1517 independent reflections
Radiation source: fine-focus sealed tube1282 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
Detector resolution: 10 pixels mm-1θmax = 26.0°, θmin = 3.2°
ω scansh = 1010
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
k = 88
Tmin = 0.953, Tmax = 0.990l = 1616
6151 measured reflections
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)] = 0.035H-atom parameters constrained
wR(F2) = 0.105 w = 1/[σ2(Fo2) + (0.0667P)2 + 0.0817P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max = 0.001
1517 reflectionsΔρmax = 0.24 e Å3
220 parametersΔρmin = 0.19 e Å3
1 restraintExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.009 (3)
Crystal data top
C16H16O8V = 707.5 (3) Å3
Mr = 336.29Z = 2
Monoclinic, P21Mo Kα radiation
a = 8.280 (2) ŵ = 0.13 mm1
b = 6.644 (2) ÅT = 293 K
c = 13.1535 (12) Å0.30 × 0.20 × 0.08 mm
β = 102.12 (2)°
Data collection top
Rigaku R-AXIS RAPID IP
diffractometer
1517 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
1282 reflections with I > 2σ(I)
Tmin = 0.953, Tmax = 0.990Rint = 0.025
6151 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0351 restraint
wR(F2) = 0.105H-atom parameters constrained
S = 1.08Δρmax = 0.24 e Å3
1517 reflectionsΔρmin = 0.19 e Å3
220 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*/UeqOcc. (<1)
O10.4354 (2)0.3424 (4)0.34450 (13)0.0399 (5)
H1A0.51530.33410.39680.060*0.50
O20.1814 (2)0.3555 (4)0.19361 (12)0.0414 (5)
O30.1725 (2)0.3863 (4)0.43528 (13)0.0384 (5)
H3A0.16590.38440.49950.058*0.50
O40.0420 (2)0.3933 (4)0.63061 (13)0.0370 (5)
H4A0.12260.40120.57250.055*0.50
O50.1000 (3)0.2810 (5)0.82507 (17)0.0571 (7)
H5A0.02330.29630.76440.086*
O60.3619 (2)0.4004 (4)0.97960 (12)0.0417 (5)
H6A0.43640.32051.03030.063*
O70.5068 (2)0.6526 (3)0.84879 (13)0.0336 (5)
H7A0.55110.71050.79900.050*
O80.5671 (2)0.3429 (4)0.54013 (13)0.0401 (6)
H8A0.55590.36360.46660.060*0.50
C10.2943 (3)0.3552 (4)0.37142 (18)0.0302 (6)
C20.1464 (3)0.3632 (4)0.28875 (18)0.0303 (6)
C30.0063 (3)0.3742 (5)0.31216 (18)0.0314 (6)
H30.09960.37810.25870.038*
C40.0247 (3)0.3798 (4)0.41735 (18)0.0284 (5)
C50.1177 (3)0.3742 (4)0.50050 (17)0.0263 (5)
C60.1023 (3)0.3820 (4)0.60602 (17)0.0268 (5)
C70.2492 (3)0.3761 (5)0.68900 (17)0.0291 (6)
C80.2301 (3)0.3980 (5)0.80142 (17)0.0311 (6)
H80.20630.53960.81300.037*
C90.3863 (3)0.3403 (4)0.87974 (18)0.0323 (6)
H90.39960.19380.87900.039*
C100.5382 (3)0.4387 (4)0.85300 (17)0.0309 (6)
C110.5585 (3)0.3595 (5)0.74721 (17)0.0319 (6)
H11A0.64250.43830.72400.038*
H11B0.59700.22130.75520.038*
C120.4022 (3)0.3671 (4)0.66537 (17)0.0294 (6)
C130.4195 (3)0.3563 (4)0.55826 (18)0.0296 (6)
C140.2770 (3)0.3626 (4)0.47627 (17)0.0262 (5)
C150.0456 (3)0.3549 (6)0.10420 (18)0.0435 (8)
H15A0.02200.23840.10680.065*
H15B0.08810.35170.04170.065*
H15C0.01960.47430.10480.065*
C160.6936 (3)0.3933 (6)0.93488 (19)0.0408 (7)
H16A0.78850.44340.91170.061*
H16B0.70390.25050.94530.061*
H16C0.68610.45750.99910.061*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0294 (10)0.0644 (15)0.0268 (8)0.0039 (10)0.0076 (7)0.0058 (10)
O20.0318 (10)0.0719 (15)0.0203 (7)0.0052 (11)0.0050 (7)0.0025 (10)
O30.0233 (9)0.0584 (13)0.0343 (9)0.0031 (10)0.0082 (7)0.0005 (10)
O40.0279 (10)0.0541 (12)0.0311 (8)0.0002 (10)0.0112 (7)0.0016 (10)
O50.0513 (14)0.0811 (19)0.0421 (11)0.0192 (13)0.0170 (10)0.0069 (12)
O60.0528 (12)0.0518 (12)0.0226 (8)0.0093 (11)0.0126 (8)0.0056 (10)
O70.0444 (11)0.0318 (10)0.0262 (8)0.0028 (9)0.0112 (7)0.0001 (8)
O80.0223 (9)0.0710 (16)0.0279 (8)0.0015 (10)0.0073 (7)0.0065 (11)
C10.0294 (13)0.0370 (15)0.0262 (11)0.0026 (13)0.0101 (9)0.0003 (12)
C20.0326 (14)0.0360 (15)0.0233 (11)0.0014 (14)0.0079 (9)0.0003 (12)
C30.0298 (13)0.0360 (14)0.0274 (11)0.0032 (13)0.0035 (9)0.0003 (12)
C40.0249 (13)0.0297 (13)0.0307 (11)0.0012 (12)0.0064 (9)0.0003 (12)
C50.0274 (13)0.0282 (12)0.0249 (11)0.0006 (12)0.0089 (9)0.0005 (12)
C60.0267 (12)0.0279 (12)0.0278 (11)0.0006 (12)0.0103 (9)0.0021 (12)
C70.0317 (13)0.0334 (13)0.0245 (11)0.0020 (13)0.0108 (9)0.0003 (12)
C80.0335 (14)0.0369 (14)0.0261 (11)0.0011 (12)0.0137 (10)0.0017 (12)
C90.0411 (15)0.0348 (14)0.0232 (10)0.0016 (13)0.0117 (10)0.0021 (11)
C100.0363 (15)0.0338 (15)0.0224 (12)0.0012 (12)0.0055 (10)0.0004 (11)
C110.0283 (13)0.0429 (16)0.0251 (11)0.0016 (13)0.0067 (9)0.0028 (12)
C120.0304 (13)0.0340 (14)0.0248 (11)0.0024 (13)0.0079 (9)0.0028 (12)
C130.0270 (13)0.0370 (15)0.0262 (11)0.0028 (12)0.0087 (9)0.0019 (11)
C140.0250 (12)0.0309 (13)0.0230 (10)0.0014 (12)0.0059 (9)0.0019 (12)
C150.0381 (15)0.068 (2)0.0225 (11)0.0052 (17)0.0028 (10)0.0018 (15)
C160.0368 (15)0.0555 (17)0.0279 (12)0.0023 (15)0.0019 (10)0.0011 (14)
Geometric parameters (Å, º) top
O1—C11.293 (3)C5—C61.421 (3)
O1—H1A0.8501C5—C141.423 (3)
O2—C21.344 (3)C6—C71.454 (3)
O2—C151.447 (3)C7—C121.368 (4)
O3—C41.294 (3)C7—C81.527 (3)
O3—H3A0.8350C8—C91.524 (4)
O4—C61.304 (3)C8—H80.9800
O4—H4A0.9046C9—C101.523 (4)
O5—C81.415 (4)C9—H90.9800
O5—H5A0.9154C10—C161.525 (3)
O6—C91.427 (3)C10—C111.530 (3)
O6—H6A0.9667C11—C121.501 (3)
O7—C101.444 (3)C11—H11A0.9700
O7—H7A0.9012C11—H11B0.9700
O8—C131.296 (3)C12—C131.448 (3)
O8—H8A0.9624C13—C141.422 (3)
C1—C141.417 (3)C15—H15A0.9600
C1—C21.458 (3)C15—H15B0.9600
C2—C31.364 (4)C15—H15C0.9600
C3—C41.424 (3)C16—H16A0.9600
C3—H30.9300C16—H16B0.9600
C4—C51.431 (3)C16—H16C0.9600
C1—O1—H1A112.1C10—C9—C8111.2 (2)
C2—O2—C15118.3 (2)O6—C9—H9108.9
C4—O3—H3A108.7C10—C9—H9108.9
C6—O4—H4A110.2C8—C9—H9108.9
C8—O5—H5A99.7O7—C10—C9106.3 (2)
C9—O6—H6A106.8O7—C10—C16109.9 (2)
C10—O7—H7A110.5C9—C10—C16111.6 (2)
C13—O8—H8A106.3O7—C10—C11110.9 (2)
O1—C1—C14123.4 (2)C9—C10—C11108.4 (2)
O1—C1—C2117.6 (2)C16—C10—C11109.7 (2)
C14—C1—C2119.0 (2)C12—C11—C10113.5 (2)
O2—C2—C3127.1 (2)C12—C11—H11A108.9
O2—C2—C1112.4 (2)C10—C11—H11A108.9
C3—C2—C1120.4 (2)C12—C11—H11B108.9
C2—C3—C4120.9 (2)C10—C11—H11B108.9
C2—C3—H3119.5H11A—C11—H11B107.7
C4—C3—H3119.5C7—C12—C13120.6 (2)
O3—C4—C3118.4 (2)C7—C12—C11122.6 (2)
O3—C4—C5121.4 (2)C13—C12—C11116.7 (2)
C3—C4—C5120.2 (2)O8—C13—C14121.8 (2)
C6—C5—C14119.9 (2)O8—C13—C12118.2 (2)
C6—C5—C4121.1 (2)C14—C13—C12120.1 (2)
C14—C5—C4119.0 (2)C1—C14—C13120.0 (2)
O4—C6—C5121.3 (2)C1—C14—C5120.5 (2)
O4—C6—C7118.7 (2)C13—C14—C5119.5 (2)
C5—C6—C7120.0 (2)O2—C15—H15A109.5
C12—C7—C6119.9 (2)O2—C15—H15B109.5
C12—C7—C8120.9 (2)H15A—C15—H15B109.5
C6—C7—C8119.0 (2)O2—C15—H15C109.5
O5—C8—C9106.9 (2)H15A—C15—H15C109.5
O5—C8—C7113.5 (2)H15B—C15—H15C109.5
C9—C8—C7112.6 (2)C10—C16—H16A109.5
O5—C8—H8107.8C10—C16—H16B109.5
C9—C8—H8107.8H16A—C16—H16B109.5
C7—C8—H8107.8C10—C16—H16C109.5
O6—C9—C10112.1 (2)H16A—C16—H16C109.5
O6—C9—C8106.7 (2)H16B—C16—H16C109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O3i0.852.553.229 (3)137
O3—H3A···O8ii0.842.402.808 (3)111
O4—H4A···O8ii0.902.543.223 (3)132
O5—H5A···O40.921.852.687 (3)152
O6—H6A···O7iii0.971.922.821 (3)154
O7—H7A···O1iv0.902.112.966 (3)159
O7—H7A···O2iv0.902.403.066 (3)131
Symmetry codes: (i) x+1, y, z; (ii) x1, y, z; (iii) x+1, y1/2, z+2; (iv) x+1, y+1/2, z+1.

Experimental details

Crystal data
Chemical formulaC16H16O8
Mr336.29
Crystal system, space groupMonoclinic, P21
Temperature (K)293
a, b, c (Å)8.280 (2), 6.644 (2), 13.1535 (12)
β (°) 102.12 (2)
V3)707.5 (3)
Z2
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.30 × 0.20 × 0.08
Data collection
DiffractometerRigaku R-AXIS RAPID IP
diffractometer
Absorption correctionMulti-scan
(ABSCOR; Higashi, 1995)
Tmin, Tmax0.953, 0.990
No. of measured, independent and
observed [I > 2σ(I)] reflections
6151, 1517, 1282
Rint0.025
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.105, 1.08
No. of reflections1517
No. of parameters220
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.24, 0.19

Computer programs: PROCESS-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O3i0.852.553.229 (3)137
O3—H3A···O8ii0.842.402.808 (3)111
O4—H4A···O8ii0.902.543.223 (3)132
O5—H5A···O40.921.852.687 (3)152
O6—H6A···O7iii0.971.922.821 (3)154
O7—H7A···O1iv0.902.112.966 (3)159
O7—H7A···O2iv0.902.403.066 (3)131
Symmetry codes: (i) x+1, y, z; (ii) x1, y, z; (iii) x+1, y1/2, z+2; (iv) x+1, y+1/2, z+1.
 

Acknowledgements

The work was supported by the Science and Technology Project of Zhejiang Province (grant Nos. 2004 C22008 and 2006 C12088) and the National Natural Science Foundation of China (grant No. 30600002).

References

First citationCharudattan, R. & Rao, K. V. (1982). Appl. Environ. Microbiol. 43, 846–849.  CAS PubMed Web of Science Google Scholar
First citationEijk, G. W. van (1975). Cell. Mol. Life Sci. 31, 783–784.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationHigashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationKelly, T. & Saha, J. K. (1985). J. Org. Chem. 50, 3679–3685.  CSD CrossRef CAS Web of Science Google Scholar
First citationRigaku (1998). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationRigaku/MSC (2002). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  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