Bostrycin

Shao-Yuan Chen; Chao Huang; Chu-Long Zhang; Yu-Zhe Chen; Fu-Cheng Lin

doi:10.1107/S1600536808032030

. 2008 Oct 31;64(Pt 11):o2226. doi: 10.1107/S1600536808032030

Bostrycin

Shao-Yuan Chen ^a,^*, Chao Huang ^a, Chu-Long Zhang ^a, Yu-Zhe Chen ^b, Fu-Cheng Lin ^a

PMCID: PMC2959567 PMID: 21581081

Abstract

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 ▶); van Eijk (1975 ▶). For a related structure, see: Kelly & Saha (1985 ▶).

Experimental

Crystal data

C₁₆H₁₆O₈
M _r = 336.29
Monoclinic,
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 ▶) T _min = 0.953, T _max = 0.990
6151 measured reflections
1517 independent reflections
1282 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.105
S = 1.08
1517 reflections
220 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; 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 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808032030/xu2453sup1.cif

e-64-o2226-sup1.cif^{(17.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808032030/xu2453Isup2.hkl

e-64-o2226-Isup2.hkl^{(73.2KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	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⋯O1^iv	0.90	2.11	2.966 (3)	159
O7—H7A⋯O2^iv	0.90	2.40	3.066 (3)	131

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

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).

supplementary crystallographic information

Comment

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).

Experimental

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.