organic compounds
8-[(3,3-Dimethyloxiran-2-yl)methoxymethyl]-11-hydroxy-2-isopropenyl-5-methyl-12-oxo-1,2,3,12-tetrahydropyrano[3,2-a]xanthen-1-yl acetate
aReserch Centre for Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai, Bangkok 10330, Thailand, and bDepartment of Physics, Faculty of Science and Technology, Thammasart University, PathumThani 12121, Thailand
*Correspondence e-mail: nongnuj.j@chula.ac.th
The title compound, commonly known as 14-methoxytajixanthone-25-acetate, C28H30O8, was isolated from Emericella variecolor. The central xanthone core is approximately planar (r.m.s. deviation = 0.084 Å). The dihydropyran ring adopts a distorted half-chair conformation. The oxirane plane is oriented at an angle of 63.3 (2)° with respect to the phenol group. An intramolecular O—H⋯O hydrogen bond forms an S(6) ring. In the crystal, molecules are linked into a two-dimensional network parallel to the ab plane by weak intermolecular C—H⋯O hydrogen bonds.
Related literature
For general background to 14-methoxytajixanthone-25-acetate, see: Bringmann et al. (2003); Pornpakakul et al. (2006); Raper & Fennel (1965). For related structures, see: Fukuyama et al. (1978); Lee et al. (2005).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: SMART (Bruker, 2006); cell SAINT-Plus (Bruker, 2006); data reduction: SAINT-Plus; 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, 2009).
Supporting information
10.1107/S1600536809038343/ci2902sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809038343/ci2902Isup2.hkl
Seventy-five Erlenmeyer flasks (250 ml) containing malt extract (2 g) and water (100 ml per flask), were autoclaved twice at 121°C for 40 min. Pure culture of E.variecolor grown on PDA at room temperature for 7 days were cut into disks 8 mm in a diameter. Two disks were transferred under sterile conditions into each Erlenmeyer flask and then statically incubated for 6 weeks at room temperature. The
broth was filtered through Whatman No.1 filter paper.The mycelium (253 g wet weight) was extracted with methanol (500 ml × 10) to yield crude methanol extract that was a dark reddish solid (13.95 g). The dark reddish solid was re-extracted with ethyl acetate (500 ml × 10) to give 5.86 g of crude ethyl acetate extract. This extract was then separated by silica gel
(230–400 mesh, 100 g) and eluted with an n-hexane-ethyl acetate mixture with stepwise increasing polarity. A total of 600 fractions of 100 ml each were collected and combined on the basis of TLC profile. UV light and vanillin/H2SO4/EtOH reagent were used as detecting methods. The combined fraction (154 mg) contained the title compound as a main component. It was obtained from elution with hexane-EtOAc (80:20) and crystallized to give 14-methoxytajixanthone-25-acetate (75 mg). Suitable single crystals of the title compound were obtained by crystallization from a mixture of benzene/diethyl ether/chloroform.The methyl group of the methoxy group is disordered over two orientations with occupancies of 0.700 (13) and 0.300 (13). The C—O distances involving the disordered atoms were restrained to be equal and these atoms were subjected to a rigid bond restraint. The displacement parameters of atoms C16 and C17 were restrained to an approximate isotropic behaviour. H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å (aromatic), 0.97 Å (CH2), 0.98 Å (CH3) and O–H = 0.82 Å, and Uiso(H) = 1.2Ueq(C) and 1.5Ueq(O and Cmethyl). In the absence of significant
effects, Friedel pairs were averaged.Data collection: SMART (Bruker, 2006); cell
SAINT-Plus (Bruker, 2006); data reduction: SAINT-Plus (Bruker, 2006); 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, 2009).C28H30O8 | F(000) = 524 |
Mr = 494.54 | Dx = 1.277 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 9335 reflections |
a = 11.3323 (1) Å | θ = 1.6–30.4° |
b = 8.8199 (2) Å | µ = 0.09 mm−1 |
c = 12.8741 (3) Å | T = 293 K |
β = 91.765 (1)° | Plate, yellow |
V = 1286.15 (4) Å3 | 0.40 × 0.24 × 0.18 mm |
Z = 2 |
Bruker SMART area-detector diffractometer | 2691 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.030 |
Graphite monochromator | θmax = 30.4°, θmin = 1.6° |
ω scans | h = −16→15 |
9335 measured reflections | k = −9→12 |
3840 independent reflections | l = −18→17 |
Refinement on F2 | 16 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.056 | w = 1/[σ2(Fo2) + (0.0608P)2 + 0.2544P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.141 | (Δ/σ)max = 0.001 |
S = 1.06 | Δρmax = 0.20 e Å−3 |
3840 reflections | Δρmin = −0.27 e Å−3 |
335 parameters |
C28H30O8 | V = 1286.15 (4) Å3 |
Mr = 494.54 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 11.3323 (1) Å | µ = 0.09 mm−1 |
b = 8.8199 (2) Å | T = 293 K |
c = 12.8741 (3) Å | 0.40 × 0.24 × 0.18 mm |
β = 91.765 (1)° |
Bruker SMART area-detector diffractometer | 2691 reflections with I > 2σ(I) |
9335 measured reflections | Rint = 0.030 |
3840 independent reflections |
R[F2 > 2σ(F2)] = 0.056 | 16 restraints |
wR(F2) = 0.141 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.20 e Å−3 |
3840 reflections | Δρmin = −0.27 e Å−3 |
335 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 1.17752 (18) | 0.0959 (3) | 0.89869 (16) | 0.0466 (6) | |
O2 | 0.77214 (19) | 0.4077 (3) | 0.79097 (15) | 0.0415 (5) | |
O3 | 0.8611 (2) | 0.0712 (3) | 0.58879 (16) | 0.0455 (5) | |
O4 | 0.7032 (2) | 0.1668 (3) | 0.45891 (18) | 0.0542 (7) | |
H4 | 0.7573 | 0.1133 | 0.4816 | 0.081* | |
O5 | 0.6074 (4) | 0.7709 (4) | 0.6946 (3) | 0.0937 (12) | |
O6 | 1.0238 (2) | −0.1231 (3) | 0.70433 (16) | 0.0444 (5) | |
O7 | 1.0451 (2) | −0.1637 (3) | 0.53268 (18) | 0.0592 (7) | |
O8 | 0.4404 (3) | 0.7222 (4) | 0.8668 (3) | 0.0780 (9) | |
C1 | 1.0770 (3) | 0.0262 (4) | 0.6941 (2) | 0.0365 (6) | |
H1 | 1.0648 | 0.0638 | 0.6230 | 0.044* | |
C2 | 1.2093 (3) | 0.0120 (4) | 0.7207 (2) | 0.0435 (7) | |
H2 | 1.2384 | −0.0757 | 0.6823 | 0.052* | |
C3 | 1.2211 (3) | −0.0264 (5) | 0.8359 (2) | 0.0483 (8) | |
H3A | 1.1768 | −0.1180 | 0.8496 | 0.058* | |
H3B | 1.3033 | −0.0454 | 0.8544 | 0.058* | |
C4 | 1.0734 (3) | 0.1616 (4) | 0.8659 (2) | 0.0380 (7) | |
C5 | 1.0267 (3) | 0.2659 (4) | 0.9370 (2) | 0.0412 (7) | |
C6 | 0.9258 (3) | 0.3443 (4) | 0.9087 (2) | 0.0420 (7) | |
H6 | 0.8946 | 0.4148 | 0.9540 | 0.050* | |
C6A | 0.8702 (3) | 0.3185 (4) | 0.8119 (2) | 0.0374 (6) | |
C7 | 1.0181 (2) | 0.1313 (4) | 0.7703 (2) | 0.0336 (6) | |
C7A | 0.9106 (3) | 0.2103 (4) | 0.7430 (2) | 0.0341 (6) | |
C8 | 0.6238 (3) | 0.5019 (4) | 0.6755 (2) | 0.0415 (7) | |
C8A | 0.7130 (3) | 0.3972 (4) | 0.6967 (2) | 0.0374 (7) | |
C9 | 0.5634 (3) | 0.4873 (5) | 0.5797 (3) | 0.0490 (8) | |
H9 | 0.5037 | 0.5563 | 0.5632 | 0.059* | |
C10 | 0.5881 (3) | 0.3753 (5) | 0.5083 (3) | 0.0502 (9) | |
H10 | 0.5442 | 0.3683 | 0.4463 | 0.060* | |
C11 | 0.6781 (3) | 0.2743 (4) | 0.5299 (2) | 0.0424 (7) | |
C11A | 0.7432 (3) | 0.2835 (4) | 0.6255 (2) | 0.0370 (6) | |
C12 | 0.8409 (3) | 0.1797 (4) | 0.6476 (2) | 0.0364 (7) | |
C13 | 0.5943 (3) | 0.6298 (4) | 0.7483 (3) | 0.0468 (8) | |
H13 | 0.6479 | 0.6272 | 0.8094 | 0.056* | |
C14 | 0.4695 (3) | 0.6246 (5) | 0.7819 (3) | 0.0576 (10) | |
H14 | 0.4104 | 0.6229 | 0.7246 | 0.069* | |
C15 | 0.4291 (5) | 0.5607 (6) | 0.8791 (4) | 0.0771 (13) | |
C16 | 0.3022 (6) | 0.5108 (11) | 0.8848 (6) | 0.133 (3) | |
H16A | 0.2725 | 0.5372 | 0.9515 | 0.200* | |
H16B | 0.2974 | 0.4030 | 0.8754 | 0.200* | |
H16C | 0.2558 | 0.5604 | 0.8312 | 0.200* | |
C17 | 0.5144 (7) | 0.4907 (11) | 0.9560 (5) | 0.132 (3) | |
H17A | 0.4787 | 0.4841 | 1.0225 | 0.197* | |
H17B | 0.5843 | 0.5521 | 0.9618 | 0.197* | |
H17C | 0.5351 | 0.3909 | 0.9330 | 0.197* | |
C18 | 0.6673 (8) | 0.8824 (9) | 0.7449 (9) | 0.098 (4) | 0.694 (16) |
H18A | 0.6714 | 0.9699 | 0.7007 | 0.147* | 0.694 (16) |
H18B | 0.7458 | 0.8481 | 0.7626 | 0.147* | 0.694 (16) |
H18C | 0.6275 | 0.9087 | 0.8071 | 0.147* | 0.694 (16) |
C18' | 0.7012 (12) | 0.841 (2) | 0.6681 (17) | 0.082 (6) | 0.306 (16) |
H18D | 0.7277 | 0.8013 | 0.6036 | 0.123* | 0.306 (16) |
H18E | 0.7619 | 0.8284 | 0.7211 | 0.123* | 0.306 (16) |
H18F | 0.6840 | 0.9475 | 0.6600 | 0.123* | 0.306 (16) |
C19 | 1.0135 (3) | −0.2066 (4) | 0.6160 (3) | 0.0502 (8) | |
C20 | 0.9601 (6) | −0.3577 (6) | 0.6382 (4) | 0.1004 (19) | |
H20A | 0.9764 | −0.3843 | 0.7095 | 0.151* | |
H20B | 0.9934 | −0.4329 | 0.5938 | 0.151* | |
H20C | 0.8763 | −0.3531 | 0.6255 | 0.151* | |
C21 | 1.2826 (3) | 0.1480 (5) | 0.6893 (3) | 0.0517 (9) | |
C22 | 1.2410 (4) | 0.2625 (6) | 0.6336 (4) | 0.0888 (16) | |
H22A | 1.2908 | 0.3415 | 0.6157 | 0.107* | |
H22B | 1.1619 | 0.2644 | 0.6122 | 0.107* | |
C23 | 1.4093 (4) | 0.1446 (8) | 0.7237 (4) | 0.0872 (15) | |
H23A | 1.4408 | 0.0450 | 0.7128 | 0.131* | |
H23B | 1.4161 | 0.1695 | 0.7963 | 0.131* | |
H23C | 1.4526 | 0.2171 | 0.6844 | 0.131* | |
C24 | 1.0876 (3) | 0.2921 (5) | 1.0420 (2) | 0.0574 (10) | |
H24A | 1.1662 | 0.3290 | 1.0322 | 0.086* | |
H24B | 1.0913 | 0.1984 | 1.0799 | 0.086* | |
H24C | 1.0440 | 0.3655 | 1.0803 | 0.086* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0437 (12) | 0.0556 (15) | 0.0402 (11) | 0.0145 (11) | −0.0051 (9) | −0.0011 (10) |
O2 | 0.0442 (12) | 0.0433 (13) | 0.0365 (10) | 0.0112 (10) | −0.0044 (9) | −0.0029 (9) |
O3 | 0.0512 (12) | 0.0423 (13) | 0.0429 (11) | 0.0013 (11) | −0.0031 (9) | −0.0102 (10) |
O4 | 0.0515 (13) | 0.0636 (17) | 0.0469 (12) | −0.0014 (13) | −0.0099 (10) | −0.0169 (12) |
O5 | 0.163 (4) | 0.0434 (17) | 0.0730 (19) | −0.019 (2) | −0.031 (2) | 0.0128 (15) |
O6 | 0.0558 (13) | 0.0356 (12) | 0.0424 (11) | −0.0041 (11) | 0.0086 (9) | −0.0017 (10) |
O7 | 0.0778 (17) | 0.0538 (16) | 0.0467 (13) | 0.0035 (15) | 0.0126 (12) | −0.0099 (12) |
O8 | 0.081 (2) | 0.0619 (19) | 0.091 (2) | 0.0141 (17) | 0.0095 (17) | −0.0240 (17) |
C1 | 0.0421 (16) | 0.0315 (15) | 0.0361 (14) | −0.0008 (13) | 0.0043 (12) | −0.0003 (12) |
C2 | 0.0423 (16) | 0.0416 (18) | 0.0471 (16) | 0.0062 (15) | 0.0071 (13) | −0.0046 (14) |
C3 | 0.0473 (18) | 0.051 (2) | 0.0468 (17) | 0.0155 (17) | 0.0012 (14) | 0.0001 (16) |
C4 | 0.0396 (15) | 0.0394 (17) | 0.0348 (14) | 0.0059 (14) | −0.0006 (11) | 0.0017 (13) |
C5 | 0.0469 (17) | 0.0446 (18) | 0.0318 (14) | 0.0031 (15) | −0.0032 (12) | 0.0016 (13) |
C6 | 0.0477 (17) | 0.0451 (18) | 0.0331 (14) | 0.0090 (15) | −0.0003 (12) | −0.0062 (13) |
C6A | 0.0373 (15) | 0.0379 (16) | 0.0370 (14) | 0.0037 (13) | 0.0001 (11) | 0.0001 (13) |
C7 | 0.0357 (14) | 0.0329 (15) | 0.0322 (13) | −0.0003 (13) | 0.0020 (11) | 0.0001 (12) |
C7A | 0.0363 (14) | 0.0353 (15) | 0.0306 (13) | −0.0024 (13) | 0.0019 (11) | −0.0001 (11) |
C8 | 0.0411 (16) | 0.0392 (18) | 0.0439 (16) | −0.0010 (15) | −0.0031 (13) | 0.0029 (14) |
C8A | 0.0343 (15) | 0.0400 (16) | 0.0378 (15) | −0.0039 (14) | −0.0007 (12) | 0.0030 (13) |
C9 | 0.0422 (17) | 0.052 (2) | 0.0516 (18) | 0.0034 (17) | −0.0114 (14) | 0.0077 (17) |
C10 | 0.0459 (17) | 0.061 (2) | 0.0430 (16) | −0.0015 (18) | −0.0148 (13) | −0.0003 (16) |
C11 | 0.0354 (15) | 0.052 (2) | 0.0400 (15) | −0.0087 (15) | −0.0015 (12) | −0.0021 (15) |
C11A | 0.0337 (14) | 0.0429 (17) | 0.0342 (14) | −0.0046 (14) | −0.0007 (11) | 0.0027 (13) |
C12 | 0.0361 (14) | 0.0367 (17) | 0.0363 (14) | −0.0090 (13) | 0.0008 (12) | 0.0013 (13) |
C13 | 0.0542 (19) | 0.0408 (18) | 0.0447 (17) | 0.0050 (16) | −0.0106 (14) | 0.0046 (15) |
C14 | 0.057 (2) | 0.056 (2) | 0.060 (2) | 0.0177 (19) | −0.0058 (16) | −0.0091 (18) |
C15 | 0.085 (3) | 0.069 (3) | 0.079 (3) | −0.004 (3) | 0.024 (2) | −0.012 (2) |
C16 | 0.117 (4) | 0.136 (6) | 0.151 (5) | −0.031 (4) | 0.065 (4) | −0.048 (5) |
C17 | 0.169 (6) | 0.134 (6) | 0.093 (4) | 0.025 (5) | 0.026 (4) | 0.042 (4) |
C18 | 0.087 (6) | 0.063 (5) | 0.144 (9) | −0.021 (4) | −0.005 (6) | 0.013 (5) |
C18' | 0.095 (11) | 0.060 (9) | 0.093 (13) | 0.026 (8) | 0.020 (9) | −0.002 (9) |
C19 | 0.058 (2) | 0.0392 (19) | 0.0541 (19) | −0.0021 (17) | 0.0097 (16) | −0.0102 (16) |
C20 | 0.152 (5) | 0.057 (3) | 0.094 (3) | −0.043 (3) | 0.033 (3) | −0.022 (3) |
C21 | 0.0450 (18) | 0.057 (2) | 0.0532 (19) | −0.0070 (18) | 0.0084 (14) | −0.0058 (18) |
C22 | 0.073 (3) | 0.074 (3) | 0.119 (4) | −0.026 (3) | −0.003 (3) | 0.035 (3) |
C23 | 0.060 (2) | 0.109 (4) | 0.093 (3) | −0.022 (3) | −0.001 (2) | 0.000 (3) |
C24 | 0.064 (2) | 0.070 (3) | 0.0380 (16) | 0.017 (2) | −0.0119 (15) | −0.0120 (17) |
O1—C4 | 1.370 (4) | C9—H9 | 0.93 |
O1—C3 | 1.444 (4) | C10—C11 | 1.376 (5) |
O2—C8A | 1.372 (4) | C10—H10 | 0.93 |
O2—C6A | 1.381 (4) | C11—C11A | 1.418 (4) |
O3—C12 | 1.246 (4) | C11A—C12 | 1.458 (4) |
O4—C11 | 1.353 (4) | C13—C14 | 1.492 (5) |
O4—H4 | 0.82 | C13—H13 | 0.98 |
O5—C18' | 1.287 (11) | C14—C15 | 1.459 (6) |
O5—C18 | 1.350 (8) | C14—H14 | 0.98 |
O5—C13 | 1.434 (5) | C15—C17 | 1.496 (9) |
O6—C19 | 1.357 (4) | C15—C16 | 1.508 (8) |
O6—C1 | 1.456 (4) | C16—H16A | 0.96 |
O7—C19 | 1.202 (4) | C16—H16B | 0.96 |
O8—C14 | 1.438 (5) | C16—H16C | 0.96 |
O8—C15 | 1.439 (6) | C17—H17A | 0.96 |
C1—C7 | 1.519 (4) | C17—H17B | 0.96 |
C1—C2 | 1.533 (4) | C17—H17C | 0.96 |
C1—H1 | 0.98 | C18—H18A | 0.96 |
C2—C21 | 1.520 (5) | C18—H18B | 0.96 |
C2—C3 | 1.523 (4) | C18—H18C | 0.96 |
C2—H2 | 0.98 | C18'—H18D | 0.96 |
C3—H3A | 0.97 | C18'—H18E | 0.96 |
C3—H3B | 0.97 | C18'—H18F | 0.96 |
C4—C7 | 1.390 (4) | C19—C20 | 1.495 (6) |
C4—C5 | 1.412 (4) | C20—H20A | 0.96 |
C5—C6 | 1.376 (4) | C20—H20B | 0.96 |
C5—C24 | 1.516 (4) | C20—H20C | 0.96 |
C6—C6A | 1.398 (4) | C21—C22 | 1.318 (6) |
C6—H6 | 0.93 | C21—C23 | 1.490 (5) |
C6A—C7A | 1.389 (4) | C22—H22A | 0.93 |
C7—C7A | 1.437 (4) | C22—H22B | 0.93 |
C7A—C12 | 1.465 (4) | C23—H23A | 0.96 |
C8—C8A | 1.390 (5) | C23—H23B | 0.96 |
C8—C9 | 1.397 (4) | C23—H23C | 0.96 |
C8—C13 | 1.511 (5) | C24—H24A | 0.96 |
C8A—C11A | 1.408 (4) | C24—H24B | 0.96 |
C9—C10 | 1.384 (5) | C24—H24C | 0.96 |
C4—O1—C3 | 116.7 (2) | C14—C13—C8 | 112.8 (3) |
C8A—O2—C6A | 120.1 (2) | O5—C13—H13 | 109.7 |
C11—O4—H4 | 109.5 | C14—C13—H13 | 109.7 |
C18'—O5—C18 | 50.7 (9) | C8—C13—H13 | 109.7 |
C18'—O5—C13 | 130.2 (9) | O8—C14—C15 | 59.5 (3) |
C18—O5—C13 | 117.3 (5) | O8—C14—C13 | 116.3 (3) |
C19—O6—C1 | 116.1 (2) | C15—C14—C13 | 125.9 (4) |
C14—O8—C15 | 61.0 (3) | O8—C14—H14 | 114.5 |
O6—C1—C7 | 107.6 (2) | C15—C14—H14 | 114.5 |
O6—C1—C2 | 108.1 (3) | C13—C14—H14 | 114.5 |
C7—C1—C2 | 110.6 (2) | O8—C15—C14 | 59.5 (3) |
O6—C1—H1 | 110.1 | O8—C15—C17 | 115.1 (6) |
C7—C1—H1 | 110.1 | C14—C15—C17 | 120.9 (5) |
C2—C1—H1 | 110.1 | O8—C15—C16 | 112.5 (5) |
C21—C2—C3 | 113.7 (3) | C14—C15—C16 | 118.6 (5) |
C21—C2—C1 | 114.5 (3) | C17—C15—C16 | 116.5 (6) |
C3—C2—C1 | 106.9 (2) | C15—C16—H16A | 109.5 |
C21—C2—H2 | 107.1 | C15—C16—H16B | 109.5 |
C3—C2—H2 | 107.1 | H16A—C16—H16B | 109.5 |
C1—C2—H2 | 107.1 | C15—C16—H16C | 109.5 |
O1—C3—C2 | 111.0 (3) | H16A—C16—H16C | 109.5 |
O1—C3—H3A | 109.4 | H16B—C16—H16C | 109.5 |
C2—C3—H3A | 109.4 | C15—C17—H17A | 109.5 |
O1—C3—H3B | 109.4 | C15—C17—H17B | 109.5 |
C2—C3—H3B | 109.4 | H17A—C17—H17B | 109.5 |
H3A—C3—H3B | 108.0 | C15—C17—H17C | 109.5 |
O1—C4—C7 | 123.5 (3) | H17A—C17—H17C | 109.5 |
O1—C4—C5 | 114.3 (2) | H17B—C17—H17C | 109.5 |
C7—C4—C5 | 122.2 (3) | O5—C18—H18A | 109.5 |
C6—C5—C4 | 118.7 (3) | O5—C18—H18B | 109.5 |
C6—C5—C24 | 120.8 (3) | H18A—C18—H18B | 109.5 |
C4—C5—C24 | 120.5 (3) | O5—C18—H18C | 109.5 |
C5—C6—C6A | 120.2 (3) | H18A—C18—H18C | 109.5 |
C5—C6—H6 | 119.9 | H18B—C18—H18C | 109.5 |
C6A—C6—H6 | 119.9 | O5—C18'—H18D | 109.5 |
O2—C6A—C7A | 123.1 (3) | O5—C18'—H18E | 109.5 |
O2—C6A—C6 | 114.7 (3) | H18D—C18'—H18E | 109.5 |
C7A—C6A—C6 | 122.1 (3) | O5—C18'—H18F | 109.5 |
C4—C7—C7A | 118.6 (3) | H18D—C18'—H18F | 109.5 |
C4—C7—C1 | 119.6 (3) | H18E—C18'—H18F | 109.5 |
C7A—C7—C1 | 121.6 (2) | O7—C19—O6 | 123.8 (3) |
C6A—C7A—C7 | 118.1 (3) | O7—C19—C20 | 125.7 (4) |
C6A—C7A—C12 | 118.7 (3) | O6—C19—C20 | 110.4 (3) |
C7—C7A—C12 | 123.1 (3) | C19—C20—H20A | 109.5 |
C8A—C8—C9 | 116.4 (3) | C19—C20—H20B | 109.5 |
C8A—C8—C13 | 123.3 (3) | H20A—C20—H20B | 109.5 |
C9—C8—C13 | 120.3 (3) | C19—C20—H20C | 109.5 |
O2—C8A—C8 | 117.5 (3) | H20A—C20—H20C | 109.5 |
O2—C8A—C11A | 120.2 (3) | H20B—C20—H20C | 109.5 |
C8—C8A—C11A | 122.4 (3) | C22—C21—C23 | 120.2 (4) |
C10—C9—C8 | 123.3 (3) | C22—C21—C2 | 124.1 (3) |
C10—C9—H9 | 118.4 | C23—C21—C2 | 115.7 (4) |
C8—C9—H9 | 118.4 | C21—C22—H22A | 120.0 |
C11—C10—C9 | 119.5 (3) | C21—C22—H22B | 120.0 |
C11—C10—H10 | 120.3 | H22A—C22—H22B | 120.0 |
C9—C10—H10 | 120.3 | C21—C23—H23A | 109.5 |
O4—C11—C10 | 119.2 (3) | C21—C23—H23B | 109.5 |
O4—C11—C11A | 120.8 (3) | H23A—C23—H23B | 109.5 |
C10—C11—C11A | 120.0 (3) | C21—C23—H23C | 109.5 |
C8A—C11A—C11 | 118.4 (3) | H23A—C23—H23C | 109.5 |
C8A—C11A—C12 | 121.2 (2) | H23B—C23—H23C | 109.5 |
C11—C11A—C12 | 120.4 (3) | C5—C24—H24A | 109.5 |
O3—C12—C11A | 121.1 (3) | C5—C24—H24B | 109.5 |
O3—C12—C7A | 123.1 (3) | H24A—C24—H24B | 109.5 |
C11A—C12—C7A | 115.8 (3) | C5—C24—H24C | 109.5 |
O5—C13—C14 | 106.2 (3) | H24A—C24—H24C | 109.5 |
O5—C13—C8 | 108.7 (3) | H24B—C24—H24C | 109.5 |
C19—O6—C1—C7 | 146.2 (3) | C8—C9—C10—C11 | −1.7 (6) |
C19—O6—C1—C2 | −94.3 (3) | C9—C10—C11—O4 | −178.8 (3) |
O6—C1—C2—C21 | 166.1 (3) | C9—C10—C11—C11A | 1.3 (5) |
C7—C1—C2—C21 | −76.3 (3) | O2—C8A—C11A—C11 | 178.6 (3) |
O6—C1—C2—C3 | −67.0 (3) | C8—C8A—C11A—C11 | −1.5 (4) |
C7—C1—C2—C3 | 50.6 (3) | O2—C8A—C11A—C12 | −3.0 (4) |
C4—O1—C3—C2 | 43.6 (4) | C8—C8A—C11A—C12 | 177.0 (3) |
C21—C2—C3—O1 | 63.2 (4) | O4—C11—C11A—C8A | −179.7 (3) |
C1—C2—C3—O1 | −64.2 (4) | C10—C11—C11A—C8A | 0.2 (5) |
C3—O1—C4—C7 | −9.1 (4) | O4—C11—C11A—C12 | 1.8 (4) |
C3—O1—C4—C5 | 171.8 (3) | C10—C11—C11A—C12 | −178.3 (3) |
O1—C4—C5—C6 | 176.3 (3) | C8A—C11A—C12—O3 | 173.7 (3) |
C7—C4—C5—C6 | −2.8 (5) | C11—C11A—C12—O3 | −7.9 (4) |
O1—C4—C5—C24 | −2.9 (5) | C8A—C11A—C12—C7A | −5.3 (4) |
C7—C4—C5—C24 | 178.0 (3) | C11—C11A—C12—C7A | 173.2 (3) |
C4—C5—C6—C6A | 1.1 (5) | C6A—C7A—C12—O3 | −169.7 (3) |
C24—C5—C6—C6A | −179.7 (3) | C7—C7A—C12—O3 | 8.9 (5) |
C8A—O2—C6A—C7A | −3.2 (4) | C6A—C7A—C12—C11A | 9.2 (4) |
C8A—O2—C6A—C6 | 177.3 (3) | C7—C7A—C12—C11A | −172.2 (3) |
C5—C6—C6A—O2 | −177.9 (3) | C18'—O5—C13—C14 | 165.3 (14) |
C5—C6—C6A—C7A | 2.6 (5) | C18—O5—C13—C14 | 105.2 (7) |
O1—C4—C7—C7A | −178.3 (3) | C18'—O5—C13—C8 | −73.1 (14) |
C5—C4—C7—C7A | 0.7 (5) | C18—O5—C13—C8 | −133.2 (6) |
O1—C4—C7—C1 | −3.2 (5) | C8A—C8—C13—O5 | 121.2 (4) |
C5—C4—C7—C1 | 175.8 (3) | C9—C8—C13—O5 | −56.5 (4) |
O6—C1—C7—C4 | 98.4 (3) | C8A—C8—C13—C14 | −121.2 (3) |
C2—C1—C7—C4 | −19.5 (4) | C9—C8—C13—C14 | 61.1 (4) |
O6—C1—C7—C7A | −86.6 (3) | C15—O8—C14—C13 | −117.9 (4) |
C2—C1—C7—C7A | 155.5 (3) | O5—C13—C14—O8 | −73.3 (4) |
O2—C6A—C7A—C7 | 175.9 (3) | C8—C13—C14—O8 | 167.7 (3) |
C6—C6A—C7A—C7 | −4.6 (4) | O5—C13—C14—C15 | −143.4 (4) |
O2—C6A—C7A—C12 | −5.4 (4) | C8—C13—C14—C15 | 97.6 (5) |
C6—C6A—C7A—C12 | 174.1 (3) | C14—O8—C15—C17 | 112.5 (5) |
C4—C7—C7A—C6A | 2.9 (4) | C14—O8—C15—C16 | −111.0 (5) |
C1—C7—C7A—C6A | −172.1 (3) | C13—C14—C15—O8 | 102.1 (5) |
C4—C7—C7A—C12 | −175.7 (3) | O8—C14—C15—C17 | −102.7 (6) |
C1—C7—C7A—C12 | 9.3 (4) | C13—C14—C15—C17 | −0.6 (8) |
C6A—O2—C8A—C8 | −172.6 (3) | O8—C14—C15—C16 | 100.6 (6) |
C6A—O2—C8A—C11A | 7.4 (4) | C13—C14—C15—C16 | −157.3 (5) |
C9—C8—C8A—O2 | −178.9 (3) | C1—O6—C19—O7 | −0.2 (5) |
C13—C8—C8A—O2 | 3.3 (5) | C1—O6—C19—C20 | 178.8 (4) |
C9—C8—C8A—C11A | 1.1 (5) | C3—C2—C21—C22 | −130.7 (4) |
C13—C8—C8A—C11A | −176.6 (3) | C1—C2—C21—C22 | −7.3 (6) |
C8A—C8—C9—C10 | 0.4 (5) | C3—C2—C21—C23 | 50.6 (4) |
C13—C8—C9—C10 | 178.3 (3) | C1—C2—C21—C23 | 173.9 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4···O3 | 0.82 | 1.82 | 2.554 (3) | 148 |
C3—H3B···O8i | 0.97 | 2.57 | 3.345 (5) | 137 |
C9—H9···O4ii | 0.93 | 2.55 | 3.434 (4) | 160 |
Symmetry codes: (i) x+1, y−1, z; (ii) −x+1, y+1/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C28H30O8 |
Mr | 494.54 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 293 |
a, b, c (Å) | 11.3323 (1), 8.8199 (2), 12.8741 (3) |
β (°) | 91.765 (1) |
V (Å3) | 1286.15 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.40 × 0.24 × 0.18 |
Data collection | |
Diffractometer | Bruker SMART area-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9335, 3840, 2691 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.712 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.056, 0.141, 1.06 |
No. of reflections | 3840 |
No. of parameters | 335 |
No. of restraints | 16 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.27 |
Computer programs: SMART (Bruker, 2006), SAINT-Plus (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), publCIF (Westrip, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4···O3 | 0.82 | 1.82 | 2.554 (3) | 148 |
C3—H3B···O8i | 0.97 | 2.57 | 3.345 (5) | 137 |
C9—H9···O4ii | 0.93 | 2.55 | 3.434 (4) | 160 |
Symmetry codes: (i) x+1, y−1, z; (ii) −x+1, y+1/2, −z+1. |
Acknowledgements
The authors thank the Thailand Research Fund (grant No. DBG5080017) and the Higher Education Commission Grants for Graduate Dissertation for financial support. The Department of Chemistry, Faculty of Science, Chulalongkorn University, the Rachadapiseksompoj Endowment, Chulalongkorn University, the National Center of Excellence for Petroleum, Petrochemicals, and Advanced Materials, and the A1-B1 project, Faculty of Science, Chulalongkorn University, are also gratefully acknowledged.
References
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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.
Emericella variecolor is a perfect state of Aspergillus variecolor(syn. Aspergillus stellatus) (Raper & Fennel, 1965), which produces a variety of compounds such as xanthones (Bringmann et al., 2003; Pornpakakul et al., 2006)
Our research group has investigated metabolites of Emericella variecolor, an endophytic fungus of Croton oblongifolius. Four xanthones including shamixanthone, 14-methoxytajixanthone-25-acetate (the title compound), tajixanthone methanoate, and tajixanthone hydrate, were isolated from mycelia. All compounds were tested for cytotoxic activity against various human tumor cell lines, including gastric carcinoma, colon carcinoma, breast carcinoma, human hepatocarcinoma, and lung carcinoma. Under the test conditions it was found that 14-methoxy tajixanthone-25-acetate and tajixanthone hydrate are almost as active as doxorubicin hydrochloride against gastric carcinoma (KATO3) and breast carcinoma (BT474) (Pornpakakul et al., 2006). In this work, we report the crystal structure of 14-methoxytajixanthone-25-acetate.
The central xanthone core is approximately planar (r.m.s. deviation of 0.084 Å). The dihydropyran ring adopts a distorted half-chair conformation, with atoms C2 and C3 deviated 0.357 (3)Å and -0.315 (3) Å, respectively, out of the mean plane [r.m.s. deviation 0.214 Å]. The orientation of the isobutene side chain with respect to the acetate substitutent is indicated by the torsion angle O6—C1—C2—C21 of 166.1 (3)°, indicating a anti-periplanar conformation. The oxirane plane is inclined at an angle of 63.3 (2)° with respect to the phenol ring.
The crystal packing is stabilized by weak intermolecular C—H···O interactions (Fig.2).