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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 66| Part 9| September 2010| Page o2263
https://doi.org/10.1107/S1600536810030850

(4S,5S,6S)-4-Hy­dr­oxy-3-meth­­oxy-5-methyl-5,6-ep­­oxy­cyclo­hex-2-en-1-one

Srinuan Tansuwan,a Porntana Chanaprat,a Thapong Teerawatananond,a Nongnuj Muangsina and Surachai Pornpakakula*

aResearch Centre of Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
*Correspondence e-mail: nongnuj.j@chula.ac.th

(Received 11 July 2010; accepted 2 August 2010; online 11 August 2010)

The title compound, C8H10O4, was isolated from culture extracts of the endophytic fungus Xylaria sp. (PB-30). The cyclo­hexenone ring exhibits a flattened boat conformation. In the crystal structure, mol­ecules related by translation along the b axis are linked into chains through O—H⋯O hydrogen bonds. Weak non-classical C—H⋯O contacts are also observed in the structure.

Related literature

For background to the structures of bioactive secondary metabolites from endophytic fungus and their activities, see: Tansuwan et al. (2007[Tansuwan, S., Pornpakakul, S., Roengsumran, S., Petsom, A., Muangsin, N., Sihanonta, P. & Chaichit, N. (2007). J. Nat. Prod. 70, 1620-1623.]); Shiono et al. (2005[Shiono, Y., Murayama, T., Takahashi, K., Okada, K., Katohda, S. & Ikeda, M. (2005). Biosci. Biotechnol. Biochem. 69, 287-292.]); Mitsui et al. (2004[Mitsui, T., Miyake, Y., Kakeya, H., Osada, H. & Kataoka, T. (2004). J. Immunol. 172, 3428-3436.]). For related structures and the assignment of the absolute configuration, see: Mitsui et al. (2004[Mitsui, T., Miyake, Y., Kakeya, H., Osada, H. & Kataoka, T. (2004). J. Immunol. 172, 3428-3436.]); Shiono et al. (2005[Shiono, Y., Murayama, T., Takahashi, K., Okada, K., Katohda, S. & Ikeda, M. (2005). Biosci. Biotechnol. Biochem. 69, 287-292.]). 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

  • C8H10O4

  • Mr = 170.16

  • Orthorhombic, P 21 21 21

  • a = 4.2208 (1) Å

  • b = 7.5459 (3) Å

  • c = 25.0802 (8) Å

  • V = 798.80 (4) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.11 mm−1

  • T = 293 K

  • 0.42 × 0.40 × 0.30 mm
Data collection

  • Bruker SMART APEXII CCD area-detector diffractometer

  • 6038 measured reflections

  • 1768 independent reflections

  • 1551 reflections with I > 2σ(I)

  • Rint = 0.021
Refinement

  • R[F2 > 2σ(F2)] = 0.041

  • wR(F2) = 0.116

  • S = 1.07

  • 1768 reflections

  • 112 parameters

  • H-atom parameters constrained

  • Δρmax = 0.32 e Å−3

  • Δρmin = −0.24 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O2—H2A⋯O1i 0.82 1.99 2.8148 (17) 180
C4—H4⋯O2ii 0.98 2.54 3.521 (2) 176
C6—H6⋯O4iii 0.98 2.56 3.5208 (17) 167
Symmetry codes: (i) x, y+1, z; (ii) x-1, y, z; (iii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+2].

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wiscosin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wiscosin, 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 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810030850/cv2746sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810030850/cv2746Isup2.hkl

checkCIF report


Comment top

Endophytic fungi have been proven to be a rich source of novel structural compounds with interesting biological activities and a high level of biodiversity. In the previous investigations of bioactive compounds produced by an endophytic fungus, Xylaria sp (strain PB-30), two antimalarial benzoquinones were isolated (Tansuwan et al., 2007). As a part of our continuing search for anticancer metabolites of this fungus, we found that the title compound is one of major metabolite showing cytotoxicity against various human cell lines, for example breast ductal carcinoma (BT474), human undifferentiated lung carcinoma (CHAGO), human liver hepatoblastoma (HEP-G2), human gastric carcinoma (KATO-3), and human colon adenocarcinoma (SW620) at IC50 values of 10.51, 11.11, 6.25, 5.61 and 5.31 µg/ml, respectively.

The title compound was previously isolated from the organic extracts of the fungus xylariaceous endophytic fungus (strain YUA-026), and elucidated on the basis of spectroscopic analysis (Shiono et al., 2005). Herein we present the crystal structure of the title compound, which was isolated from the fermentation culture of the endophytic fungus Xylaria sp (strain PB-30) at room temperature under a static condition.

The cyclohexenone ring exhibits a flattened boat conformation with puckering amplitudes Q = 0.232 (1), φ = 176.5 (3)° and θ = 81.8°. The 3-methoxy substitutent is in the plane of the cyclohexenone ring to which it is attached [dihedral angle = 7.4 (2)°]. Epoxide ring makes dihedral angles of 87.23 (6)° with the cyclohexenone rings C1—C6. The hydroxyl group locates on the same side of the epoxide ring. In the crystal, the molecules are linked to each other through O—H···O hydrogen bonds, building a polymeric chain parallel to the b-axis. Weak non-classical C—H···O contacts are also observed in the structure. The absolute configuration could not be determined therefore it was assigned on the basis of literature data (Shiono et al., 2005).

Related literature top

For background to the structures of bioactive secondary metabolites from endophytic fungus and their activities, see: Tansuwan et al. (2007); Shiono et al. (2005); Mitsui et al. (2004). For related structures and the assignment of the absolute configuration, see: Mitsui et al. (2004); Shiono et al. (2005). For puckering parameters, see: Cremer & Pople (1975).

Experimental top

The endophytic fungus Xylaria sp. PB-30 was cultivated in 100 ml of malt extract broth (MEB) in a 250 ml flask (x 300) under static condition at room temperature for 35 days. The culture was filtered through filter paper (Whatman No.1). The culture broth (23 L) was concentrated by rotary evaporator in vacuo to give the concentrated broth (1.5 L) and then extracted with EtOAc (x5), CH2Cl2: MeOH (1:1) (x5) and MeOH (x5), respectively. The solvents were evaporated under reduced pressure at 30°C to give EtOAc crude as yellow viscous liquid (29.61 g), CH2Cl2: MeOH crude as brown viscous liquid (21.45 g) and MeOH crude as brown viscous liquid (4.74 g).

The EtOAc crude extract (29.61 g) was subjected to a column chromatography [SephadexTM LH-20 (400 g), column diameter 3.6 cm] using 5% dichloromethane in MeOH as eluent. 10 ml of each fraction was collected. The similar fractions were combined on the basis of TLC profile and monitored by UV, iodine vapor and vanillin/H2SO4 reagent to give 14 combined fractions.

The fractions EB-5 and EB-6 were combined and purified by crystallization from a 1:1 mixture of CH2Cl2 and acetone to obtain the title compound as colorless crystals (25.8 mg).

m.p. 153–155¯C; [α]D 20 -100 o (c = 0.1, MeOH); λmax (MeOH) (log ε) 260 nm (3.75); HRESIMS m/z 363.0579 [2M+Na]+ calc. for (C8H10O4)2 Na 363.1055 FT—IR (KBr) vmax (cm-1): 3445, 3070, 3033, 2987, 2940, 2917, 2857, 1642, 1605, 1386, 1300, 1253, 1213, 1070, and 1014; 1H-NMR δ (CDCl3, 400 MHz) 1.64 (3H, s, Me), 2.58 (1H, d, J=6.0 Hz, 4-OH), 3.32 (1H, d, J=2.0 Hz, 6-H), 3.76 (3H, s, OMe), 4.48 (1H, d, J=6.0 Hz, 4-H) and 5.25 (1H, d, J= 2.0 Hz, 2-H) p.p.m.; 13C-NMR δ (CDCl3, 100 MHz) 18.9 (Me), 56.6 (OMe), 59.4 (C-5), 60.5 (C-6), 69.1 (C-4), 98.2 (C-2), 171.3 (C-3) and 193.4 (C-1) p.p.m.

Refinement top

All H atoms were positioned geometrically and treated as riding, with C—H bonding lengths constrained to 0.93 Å (aromatic CH), 0.96 Å (methyl CH3), 0.97 Å (methylene CH2), and O—H = 0.84 Å, and with Uiso(H) = 1.2Ueq(CH) or Uiso(H) = 1.5Ueq(CH3, methylene C or OH). 1159 Friedel pair were merged before the final refinement. The absolute configuration was assigned on the basis of the known configuration of the starting material as R, S and S for C4, C5 and C6-positions, respectively.

Structure description top

Endophytic fungi have been proven to be a rich source of novel structural compounds with interesting biological activities and a high level of biodiversity. In the previous investigations of bioactive compounds produced by an endophytic fungus, Xylaria sp (strain PB-30), two antimalarial benzoquinones were isolated (Tansuwan et al., 2007). As a part of our continuing search for anticancer metabolites of this fungus, we found that the title compound is one of major metabolite showing cytotoxicity against various human cell lines, for example breast ductal carcinoma (BT474), human undifferentiated lung carcinoma (CHAGO), human liver hepatoblastoma (HEP-G2), human gastric carcinoma (KATO-3), and human colon adenocarcinoma (SW620) at IC50 values of 10.51, 11.11, 6.25, 5.61 and 5.31 µg/ml, respectively.

The title compound was previously isolated from the organic extracts of the fungus xylariaceous endophytic fungus (strain YUA-026), and elucidated on the basis of spectroscopic analysis (Shiono et al., 2005). Herein we present the crystal structure of the title compound, which was isolated from the fermentation culture of the endophytic fungus Xylaria sp (strain PB-30) at room temperature under a static condition.

The cyclohexenone ring exhibits a flattened boat conformation with puckering amplitudes Q = 0.232 (1), φ = 176.5 (3)° and θ = 81.8°. The 3-methoxy substitutent is in the plane of the cyclohexenone ring to which it is attached [dihedral angle = 7.4 (2)°]. Epoxide ring makes dihedral angles of 87.23 (6)° with the cyclohexenone rings C1—C6. The hydroxyl group locates on the same side of the epoxide ring. In the crystal, the molecules are linked to each other through O—H···O hydrogen bonds, building a polymeric chain parallel to the b-axis. Weak non-classical C—H···O contacts are also observed in the structure. The absolute configuration could not be determined therefore it was assigned on the basis of literature data (Shiono et al., 2005).

For background to the structures of bioactive secondary metabolites from endophytic fungus and their activities, see: Tansuwan et al. (2007); Shiono et al. (2005); Mitsui et al. (2004). For related structures and the assignment of the absolute configuration, see: Mitsui et al. (2004); Shiono et al. (2005). For puckering parameters, see: Cremer & Pople (1975).

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 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme. Hydrogen atoms are shown as spheres of arbitrary radius.
(4S,5S,6S)-4-Hydroxy-3-methoxy-5-methyl-5,6- epoxycyclohex-2-en-1-one top
Crystal data top
C8H10O4F(000) = 360
Mr = 170.16Dx = 1.415 Mg m−3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 2855 reflections
a = 4.2208 (1) Åθ = 2.8–32.8°
b = 7.5459 (3) ŵ = 0.11 mm−1
c = 25.0802 (8) ÅT = 293 K
V = 798.80 (4) Å3Prism, colourless
Z = 40.42 × 0.40 × 0.30 mm
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		1551 reflections with I > 2σ(I)
Radiation source: MoRint = 0.021
Graphite monochromatorθmax = 33.1°, θmin = 2.8°
φ and ω scansh = −6→6
6038 measured reflectionsk = −11→7
1768 independent reflectionsl = −37→32
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.041 w = 1/[σ2(Fo2) + (0.0798P)2 + 0.0232P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.116(Δ/σ)max = 0.001
S = 1.07Δρmax = 0.32 e Å−3
1768 reflectionsΔρmin = −0.24 e Å−3
112 parameters
Crystal data top
C8H10O4V = 798.80 (4) Å3
Mr = 170.16Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 4.2208 (1) ŵ = 0.11 mm−1
b = 7.5459 (3) ÅT = 293 K
c = 25.0802 (8) Å0.42 × 0.40 × 0.30 mm
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		1551 reflections with I > 2σ(I)
6038 measured reflectionsRint = 0.021
1768 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0410 restraints
wR(F2) = 0.116H-atom parameters constrained
S = 1.07Δρmax = 0.32 e Å−3
1768 reflectionsΔρmin = −0.24 e Å−3
112 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.6030 (4)0.12154 (17)0.88766 (6)0.0349 (3)
C20.6543 (4)0.19049 (16)0.83465 (5)0.0337 (3)
H20.67780.11210.80630.04*
C30.6687 (3)0.36664 (16)0.82548 (5)0.0268 (2)
C40.6073 (3)0.50632 (15)0.86741 (5)0.0248 (2)
H40.38940.54890.86320.03*
C50.6459 (3)0.43752 (15)0.92384 (5)0.0242 (2)
C60.6377 (4)0.24623 (17)0.93348 (5)0.0293 (3)
H60.55860.20640.96820.035*
C70.5554 (5)0.56563 (19)0.96737 (5)0.0372 (3)
H7A0.6780.67210.96380.056*
H7B0.59640.51281.00150.056*
H7C0.33420.59360.96450.056*
C80.7980 (6)0.3240 (2)0.73390 (6)0.0452 (4)
H8A0.62170.24770.72640.068*
H8B0.97910.25370.74330.068*
H8C0.84610.39380.70290.068*
O10.5405 (5)−0.03468 (14)0.89674 (5)0.0594 (5)
O20.8156 (3)0.65036 (13)0.85837 (4)0.0392 (3)
H2A0.7350.74190.86960.059*
O30.7187 (4)0.43952 (13)0.77758 (4)0.0379 (3)
O40.9367 (3)0.34098 (15)0.93283 (4)0.0350 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0486 (8)0.0182 (5)0.0379 (6)0.0011 (5)0.0071 (7)−0.0006 (4)
C20.0484 (8)0.0210 (5)0.0318 (6)−0.0004 (5)0.0055 (6)−0.0066 (4)
C30.0325 (6)0.0226 (5)0.0253 (5)0.0013 (5)0.0029 (5)−0.0029 (4)
C40.0297 (5)0.0174 (4)0.0272 (5)0.0020 (4)0.0042 (4)−0.0011 (4)
C50.0254 (5)0.0211 (5)0.0261 (5)−0.0009 (4)0.0018 (4)−0.0029 (4)
C60.0360 (6)0.0231 (5)0.0289 (5)0.0008 (5)0.0029 (5)0.0024 (4)
C70.0521 (9)0.0286 (6)0.0310 (6)−0.0041 (6)0.0082 (6)−0.0093 (5)
C80.0645 (11)0.0422 (8)0.0290 (6)0.0011 (9)0.0103 (7)−0.0080 (6)
O10.1057 (14)0.0182 (4)0.0545 (7)−0.0065 (6)0.0200 (9)0.0002 (4)
O20.0545 (7)0.0199 (4)0.0431 (5)−0.0081 (4)0.0158 (5)−0.0024 (4)
O30.0593 (7)0.0294 (4)0.0250 (4)0.0029 (5)0.0074 (5)−0.0019 (3)
O40.0280 (5)0.0368 (5)0.0400 (5)0.0022 (4)−0.0047 (4)0.0019 (4)
Geometric parameters (Å, º) top
C1—O11.2292 (17)C5—C71.5074 (17)
C1—C21.444 (2)C6—O41.4506 (18)
C1—C61.4924 (19)C6—H60.98
C2—C31.3503 (17)C7—H7A0.96
C2—H20.93C7—H7B0.96
C3—O31.3379 (15)C7—H7C0.96
C3—C41.5113 (16)C8—O31.4393 (17)
C4—O21.4162 (17)C8—H8A0.96
C4—C51.5162 (17)C8—H8B0.96
C4—H40.98C8—H8C0.96
C5—O41.4448 (16)O2—H2A0.82
C5—C61.4640 (18)
O1—C1—C2123.24 (14)O4—C6—C559.43 (9)
O1—C1—C6118.88 (14)O4—C6—C1112.79 (12)
C2—C1—C6117.85 (12)C5—C6—C1119.79 (11)
C3—C2—C1121.21 (11)O4—C6—H6117.2
C3—C2—H2119.4C5—C6—H6117.2
C1—C2—H2119.4C1—C6—H6117.2
O3—C3—C2124.38 (11)C5—C7—H7A109.5
O3—C3—C4111.41 (10)C5—C7—H7B109.5
C2—C3—C4124.08 (11)H7A—C7—H7B109.5
O2—C4—C3108.50 (10)C5—C7—H7C109.5
O2—C4—C5110.21 (11)H7A—C7—H7C109.5
C3—C4—C5113.09 (10)H7B—C7—H7C109.5
O2—C4—H4108.3O3—C8—H8A109.5
C3—C4—H4108.3O3—C8—H8B109.5
C5—C4—H4108.3H8A—C8—H8B109.5
O4—C5—C659.82 (9)O3—C8—H8C109.5
O4—C5—C7115.19 (12)H8A—C8—H8C109.5
C6—C5—C7120.44 (11)H8B—C8—H8C109.5
O4—C5—C4114.18 (10)C4—O2—H2A109.5
C6—C5—C4119.29 (10)C3—O3—C8118.11 (11)
C7—C5—C4115.41 (11)C5—O4—C660.75 (8)
O1—C1—C2—C3168.6 (2)C7—C5—C6—O4−103.26 (15)
C6—C1—C2—C3−13.3 (3)C4—C5—C6—O4102.54 (13)
C1—C2—C3—O3179.30 (16)O4—C5—C6—C1−100.39 (15)
C1—C2—C3—C4−5.2 (3)C7—C5—C6—C1156.36 (15)
O3—C3—C4—O2−40.34 (16)C4—C5—C6—C12.2 (2)
C2—C3—C4—O2143.68 (16)O1—C1—C6—O4125.98 (19)
O3—C3—C4—C5−162.94 (13)C2—C1—C6—O4−52.22 (19)
C2—C3—C4—C521.1 (2)O1—C1—C6—C5−167.29 (19)
O2—C4—C5—O4−72.54 (13)C2—C1—C6—C514.5 (2)
C3—C4—C5—O449.10 (15)C2—C3—O3—C8−7.4 (3)
O2—C4—C5—C6−140.21 (13)C4—C3—O3—C8176.65 (16)
C3—C4—C5—C6−18.57 (18)C7—C5—O4—C6111.98 (13)
O2—C4—C5—C764.33 (16)C4—C5—O4—C6−111.05 (12)
C3—C4—C5—C7−174.03 (13)C1—C6—O4—C5112.19 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2A···O1i0.821.992.8148 (17)180
C4—H4···O2ii0.982.543.521 (2)176
C6—H6···O4iii0.982.563.5208 (17)167
Symmetry codes: (i) x, y+1, z; (ii) x−1, y, z; (iii) x−1/2, −y+1/2, −z+2.

Experimental details

Crystal data
Chemical formulaC8H10O4
Mr170.16
Crystal system, space groupOrthorhombic, P212121
Temperature (K)293
a, b, c (Å)4.2208 (1), 7.5459 (3), 25.0802 (8)
V (Å3)798.80 (4)
Z4
Radiation typeMo Kα
µ (mm−1)0.11
Crystal size (mm)0.42 × 0.40 × 0.30
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
Absorption correction–
No. of measured, independent and
observed [I > 2σ(I)] reflections		6038, 1768, 1551
Rint0.021
(sin θ/λ)max (Å−1)0.768
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.116, 1.07
No. of reflections1768
No. of parameters112
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.32, −0.24

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2A···O1i0.821.992.8148 (17)179.7
C4—H4···O2ii0.982.543.521 (2)176.1
C6—H6···O4iii0.982.563.5208 (17)166.7
Symmetry codes: (i) x, y+1, z; (ii) x−1, y, z; (iii) x−1/2, −y+1/2, −z+2.
 

Acknowledgements

Financial support from the Department of Chemistry, Faculty of Science, Chulalongkorn University, the Rachadapiseksompoj Endowment, Chulalongkorn University, the Thailand research fund (grant No. MRG5280213), the National Center of Excellence for Petroleum, Petrochemicals and Advanced Materials, and the A1–B1 project, Faculty of Science, Chulalongkorn University, is gratefully acknowledged. The Thai Government Stimulus Package 2 (TKK2555), under the Project for Establishment of a Comprehensive Center for Innovative Food, Health Products and Agriculture, is acknowledged for support of the X-ray Crystallographic analysis.

References

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ISSN: 2056-9890
Volume 66| Part 9| September 2010| Page o2263
https://doi.org/10.1107/S1600536810030850
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