organic compounds
Lacinilene C 7-methyl ether
aA.S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Mirzo Ulugbek str. 83, Tashkent 100125, Uzbekistan, and bSouthern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845, USA
*Correspondence e-mail: via74@yandex.ru
The title compound, C16H20O3 [systematic name: 1-hydroxy-7-methoxy-1,6-dimethyl-4-(propan-2-yl)naphthalen-2(1H)-one], is a sesquiterpene isolated from foliar tissues of the cotton plant and is of interest with respect to its antibacterial properties. Its phenyl ring is ideally planar, and the maximum of deviation in the second ring is 0.386 (3) Å. The hydroxy group and the methyl group are oriented in an equatorial fashion and axial, respectively, to the second ring. In the crystal, inversion dimers are formed through pairs of O—H⋯O hydrogen bonds. Weak C—H⋯O hydrogen bonds link the dimers into columns along the c axis. These columns form a with a crystal packing factor of 0.66.
Related literature
For the original isolation from Ulmus laciniata Mayr and proposed structure, see: Suzuki et al. (1972). For isolation from cotton bracts (Gossypium), identification and structure definition, see: Stipanovic et al. (1975, 1981). For information on the biological activity, see: Essenberg et al. (1982). For biosynthetic studies, see: Stipanovic et al. (1981); Essenberg et al. (1985).
Experimental
Crystal data
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Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell CrysAlis PRO; data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536813021430/rk2406sup1.cif
contains datablocks I, exp1290. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813021430/rk2406Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536813021430/rk2406Isup3.cml
The title compound was isolated from frost–killed cotton bracts (Gossypium species) by extraction and silica gel LC procedures as previously described (Stipanovic et al., 1981). For achieving separation of the closely related compounds, the partially purified fraction was further chromatographed by consecutive injections on semi–preparative RP–HPLC column (Agilent 1100 HPLC system; Zorbax Eclipse XDB C8 column 9.4× 250 mm, 5µm; Agilent Technologies Inc, USA). The column was eluted using a linear gradient of H2O (A) /CH3OH (B) (HPLC grade, Sigma–Aldrich, DE) from 60 to 90% B for 30 minutes at a flow rate of 3 ml/min with the following segment of 100% B within 5 minutes and eluates were monitored at 254 nm. Crystals were obtained by slow evaporation of the HPLC
and the most appropriate for X-ray diffraction were collected (m.p. 57–60°C).All H atoms were placed in geometrically idealized positions C—H = 0.98Å for methine H, C—H = 0.96Å for methyl H and C—H = 0.93Å for aromatic H and treated as riding on their parent atoms, with Uiso(H) = 1.5Ueq(C) for methyl H; Uiso(H) = 1.2Ueq(C) for aromatic and methine H. The H atom of hydroxy group was refined freely.
Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell
CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C16H20O3 | Z = 2 |
Mr = 260.32 | F(000) = 280 |
Triclinic, P1 | Dx = 1.194 Mg m−3 |
a = 8.285 (2) Å | Cu Kα radiation, λ = 1.54184 Å |
b = 8.987 (2) Å | Cell parameters from 602 reflections |
c = 10.665 (3) Å | θ = 4.5–77.4° |
α = 68.58 (2)° | µ = 0.65 mm−1 |
β = 78.95 (2)° | T = 295 K |
γ = 88.87 (2)° | Block, white |
V = 724.4 (3) Å3 | 0.34 × 0.27 × 0.20 mm |
Oxford Diffraction Xcalibur Ruby CCD diffractometer | 2927 independent reflections |
Radiation source: fine–focus sealed tube | 1928 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
ω scans | θmax = 75.9°, θmin = 4.5° |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | h = −9→10 |
Tmin = 0.809, Tmax = 0.878 | k = −10→11 |
6210 measured reflections | l = −13→13 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.051 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.171 | w = 1/[σ2(Fo2) + (0.0933P)2 + 0.0437P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max < 0.001 |
2927 reflections | Δρmax = 0.18 e Å−3 |
182 parameters | Δρmin = −0.18 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.008 (2) |
C16H20O3 | γ = 88.87 (2)° |
Mr = 260.32 | V = 724.4 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 8.285 (2) Å | Cu Kα radiation |
b = 8.987 (2) Å | µ = 0.65 mm−1 |
c = 10.665 (3) Å | T = 295 K |
α = 68.58 (2)° | 0.34 × 0.27 × 0.20 mm |
β = 78.95 (2)° |
Oxford Diffraction Xcalibur Ruby CCD diffractometer | 2927 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | 1928 reflections with I > 2σ(I) |
Tmin = 0.809, Tmax = 0.878 | Rint = 0.030 |
6210 measured reflections |
R[F2 > 2σ(F2)] = 0.051 | 0 restraints |
wR(F2) = 0.171 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 0.18 e Å−3 |
2927 reflections | Δρmin = −0.18 e Å−3 |
182 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.17788 (19) | 0.7003 (2) | 0.39017 (14) | 0.0736 (5) | |
O2 | 0.3720 (2) | 0.6105 (2) | 1.03293 (16) | 0.0881 (6) | |
O3 | 0.48189 (19) | 0.6395 (2) | 0.76954 (16) | 0.0745 (5) | |
C1 | 0.2611 (2) | 0.7114 (2) | 0.59257 (18) | 0.0557 (5) | |
H1 | 0.3710 | 0.7002 | 0.5588 | 0.067* | |
C2 | 0.1443 (3) | 0.7162 (2) | 0.51528 (18) | 0.0564 (5) | |
C3 | −0.0215 (3) | 0.7362 (3) | 0.56220 (19) | 0.0587 (5) | |
C4 | −0.0648 (2) | 0.7455 (2) | 0.69137 (19) | 0.0562 (5) | |
H4 | −0.1747 | 0.7574 | 0.7244 | 0.067* | |
C5 | 0.0011 (2) | 0.7369 (2) | 0.91560 (18) | 0.0507 (5) | |
C6 | 0.1106 (3) | 0.7009 (2) | 0.99895 (19) | 0.0587 (5) | |
H6 | 0.0762 | 0.6946 | 1.0891 | 0.070* | |
C7 | 0.2793 (3) | 0.6715 (2) | 0.9538 (2) | 0.0600 (5) | |
C8 | 0.3471 (2) | 0.7286 (2) | 0.79945 (19) | 0.0553 (5) | |
C9 | 0.2154 (2) | 0.7232 (2) | 0.72078 (17) | 0.0491 (4) | |
C10 | 0.0498 (2) | 0.7378 (2) | 0.77398 (17) | 0.0488 (4) | |
C11 | −0.1470 (3) | 0.7475 (4) | 0.4749 (2) | 0.0851 (8) | |
H11B | −0.1295 | 0.8479 | 0.3985 | 0.128* | |
H11A | −0.2555 | 0.7405 | 0.5288 | 0.128* | |
H11C | −0.1361 | 0.6613 | 0.4415 | 0.128* | |
C12 | 0.4083 (3) | 0.9043 (3) | 0.7538 (3) | 0.0790 (7) | |
H12A | 0.4528 | 0.9453 | 0.6569 | 0.119* | |
H12B | 0.4922 | 0.9110 | 0.8026 | 0.119* | |
H12C | 0.3180 | 0.9662 | 0.7735 | 0.119* | |
C13 | 0.3426 (3) | 0.6738 (3) | 0.3381 (2) | 0.0823 (7) | |
H13B | 0.3478 | 0.6595 | 0.2526 | 0.123* | |
H13C | 0.3780 | 0.5796 | 0.4030 | 0.123* | |
H13A | 0.4132 | 0.7644 | 0.3237 | 0.123* | |
C14 | −0.1737 (2) | 0.7743 (2) | 0.9643 (2) | 0.0574 (5) | |
H14 | −0.2483 | 0.7155 | 0.9353 | 0.069* | |
C15 | −0.2245 (3) | 0.7260 (3) | 1.1202 (2) | 0.0831 (7) | |
H15A | −0.2059 | 0.6148 | 1.1644 | 0.125* | |
H15C | −0.3391 | 0.7434 | 1.1438 | 0.125* | |
H15B | −0.1602 | 0.7895 | 1.1501 | 0.125* | |
C16 | −0.1950 (3) | 0.9525 (3) | 0.8936 (3) | 0.0731 (6) | |
H16C | −0.1205 | 1.0129 | 0.9180 | 0.110* | |
H16A | −0.3062 | 0.9764 | 0.9224 | 0.110* | |
H16B | −0.1715 | 0.9804 | 0.7958 | 0.110* | |
H3 | 0.506 (4) | 0.574 (4) | 0.846 (3) | 0.116 (11)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0766 (10) | 0.1039 (12) | 0.0479 (7) | 0.0129 (9) | −0.0140 (7) | −0.0365 (8) |
O2 | 0.0990 (13) | 0.1237 (15) | 0.0674 (9) | 0.0631 (11) | −0.0479 (9) | −0.0525 (10) |
O3 | 0.0641 (10) | 0.1039 (12) | 0.0623 (9) | 0.0395 (9) | −0.0222 (7) | −0.0353 (9) |
C1 | 0.0544 (11) | 0.0652 (12) | 0.0471 (9) | 0.0130 (9) | −0.0102 (8) | −0.0209 (8) |
C2 | 0.0646 (13) | 0.0645 (12) | 0.0406 (9) | 0.0096 (10) | −0.0127 (8) | −0.0191 (8) |
C3 | 0.0590 (12) | 0.0712 (13) | 0.0483 (10) | 0.0047 (10) | −0.0171 (8) | −0.0218 (9) |
C4 | 0.0492 (10) | 0.0690 (12) | 0.0531 (10) | 0.0082 (9) | −0.0114 (8) | −0.0252 (9) |
C5 | 0.0593 (12) | 0.0463 (9) | 0.0488 (9) | 0.0058 (8) | −0.0095 (8) | −0.0208 (7) |
C6 | 0.0729 (13) | 0.0645 (12) | 0.0456 (9) | 0.0192 (10) | −0.0167 (8) | −0.0267 (9) |
C7 | 0.0737 (13) | 0.0652 (12) | 0.0564 (11) | 0.0285 (10) | −0.0302 (9) | −0.0328 (9) |
C8 | 0.0525 (11) | 0.0648 (12) | 0.0559 (10) | 0.0179 (9) | −0.0197 (8) | −0.0270 (9) |
C9 | 0.0517 (11) | 0.0524 (10) | 0.0455 (9) | 0.0112 (8) | −0.0149 (7) | −0.0186 (8) |
C10 | 0.0522 (11) | 0.0507 (10) | 0.0462 (9) | 0.0083 (8) | −0.0131 (7) | −0.0197 (8) |
C11 | 0.0675 (15) | 0.131 (2) | 0.0654 (13) | 0.0055 (15) | −0.0253 (11) | −0.0406 (14) |
C12 | 0.0713 (15) | 0.0798 (16) | 0.0950 (17) | 0.0025 (12) | −0.0364 (13) | −0.0327 (13) |
C13 | 0.0836 (17) | 0.111 (2) | 0.0601 (12) | 0.0176 (15) | −0.0069 (11) | −0.0448 (13) |
C14 | 0.0516 (11) | 0.0654 (12) | 0.0612 (11) | −0.0013 (9) | −0.0058 (8) | −0.0328 (9) |
C15 | 0.0754 (16) | 0.1040 (19) | 0.0696 (14) | −0.0020 (14) | 0.0076 (11) | −0.0425 (13) |
C16 | 0.0605 (14) | 0.0741 (14) | 0.0950 (16) | 0.0190 (11) | −0.0206 (12) | −0.0412 (13) |
O1—C2 | 1.369 (2) | C8—C12 | 1.537 (3) |
O1—C13 | 1.421 (3) | C9—C10 | 1.403 (2) |
O2—C7 | 1.224 (2) | C11—H11B | 0.9600 |
O3—C8 | 1.416 (2) | C11—H11A | 0.9600 |
O3—H3 | 0.87 (3) | C11—H11C | 0.9600 |
C1—C2 | 1.377 (3) | C12—H12A | 0.9600 |
C1—C9 | 1.389 (2) | C12—H12B | 0.9600 |
C1—H1 | 0.9300 | C12—H12C | 0.9600 |
C2—C3 | 1.401 (3) | C13—H13B | 0.9600 |
C3—C4 | 1.388 (3) | C13—H13C | 0.9600 |
C3—C11 | 1.502 (3) | C13—H13A | 0.9600 |
C4—C10 | 1.399 (3) | C14—C16 | 1.524 (3) |
C4—H4 | 0.9300 | C14—C15 | 1.530 (3) |
C5—C6 | 1.343 (3) | C14—H14 | 0.9800 |
C5—C10 | 1.484 (2) | C15—H15A | 0.9600 |
C5—C14 | 1.517 (3) | C15—H15C | 0.9600 |
C6—C7 | 1.441 (3) | C15—H15B | 0.9600 |
C6—H6 | 0.9300 | C16—H16C | 0.9600 |
C7—C8 | 1.526 (3) | C16—H16A | 0.9600 |
C8—C9 | 1.510 (2) | C16—H16B | 0.9600 |
C2—O1—C13 | 118.06 (17) | C3—C11—H11A | 109.5 |
C8—O3—H3 | 109 (2) | H11B—C11—H11A | 109.5 |
C2—C1—C9 | 120.19 (18) | C3—C11—H11C | 109.5 |
C2—C1—H1 | 119.9 | H11B—C11—H11C | 109.5 |
C9—C1—H1 | 119.9 | H11A—C11—H11C | 109.5 |
O1—C2—C1 | 123.97 (18) | C8—C12—H12A | 109.5 |
O1—C2—C3 | 114.86 (17) | C8—C12—H12B | 109.5 |
C1—C2—C3 | 121.16 (17) | H12A—C12—H12B | 109.5 |
C4—C3—C2 | 117.66 (18) | C8—C12—H12C | 109.5 |
C4—C3—C11 | 121.55 (19) | H12A—C12—H12C | 109.5 |
C2—C3—C11 | 120.78 (18) | H12B—C12—H12C | 109.5 |
C3—C4—C10 | 122.77 (18) | O1—C13—H13B | 109.5 |
C3—C4—H4 | 118.6 | O1—C13—H13C | 109.5 |
C10—C4—H4 | 118.6 | H13B—C13—H13C | 109.5 |
C6—C5—C10 | 119.94 (17) | O1—C13—H13A | 109.5 |
C6—C5—C14 | 121.17 (16) | H13B—C13—H13A | 109.5 |
C10—C5—C14 | 118.89 (16) | H13C—C13—H13A | 109.5 |
C5—C6—C7 | 122.39 (17) | C5—C14—C16 | 109.12 (17) |
C5—C6—H6 | 118.8 | C5—C14—C15 | 114.28 (18) |
C7—C6—H6 | 118.8 | C16—C14—C15 | 109.79 (18) |
O2—C7—C6 | 123.11 (19) | C5—C14—H14 | 107.8 |
O2—C7—C8 | 118.86 (19) | C16—C14—H14 | 107.8 |
C6—C7—C8 | 117.93 (16) | C15—C14—H14 | 107.8 |
O3—C8—C9 | 110.78 (15) | C14—C15—H15A | 109.5 |
O3—C8—C7 | 111.14 (15) | C14—C15—H15C | 109.5 |
C9—C8—C7 | 111.84 (17) | H15A—C15—H15C | 109.5 |
O3—C8—C12 | 108.56 (18) | C14—C15—H15B | 109.5 |
C9—C8—C12 | 107.82 (16) | H15A—C15—H15B | 109.5 |
C7—C8—C12 | 106.49 (17) | H15C—C15—H15B | 109.5 |
C1—C9—C10 | 120.60 (17) | C14—C16—H16C | 109.5 |
C1—C9—C8 | 119.16 (17) | C14—C16—H16A | 109.5 |
C10—C9—C8 | 120.17 (15) | H16C—C16—H16A | 109.5 |
C4—C10—C9 | 117.56 (16) | C14—C16—H16B | 109.5 |
C4—C10—C5 | 122.48 (17) | H16C—C16—H16B | 109.5 |
C9—C10—C5 | 119.89 (16) | H16A—C16—H16B | 109.5 |
C3—C11—H11B | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O2i | 0.87 (3) | 2.08 (3) | 2.892 (2) | 156.3 |
C13—H13B···O2ii | 0.96 | 2.51 | 3.467 (2) | 177 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, y, z−1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O2i | 0.87 (3) | 2.08 (3) | 2.892 (2) | 156.3 |
C13—H13B···O2ii | 0.96 | 2.51 | 3.467 (2) | 177 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, y, z−1. |
Acknowledgements
The authors thank the Academy of Sciences of the Republic of Uzbekistan for supporting this work (project Nos. F7–T048 and I5–FA–18897)
References
Essenberg, M., Doherty, M. d'A., Hamilton, B. K., Henning, V. T., Cover, E. C., Mcfaul, S. J. & Johnson, W. M. (1982). Phytopathology, 72, 1349–1356. CrossRef CAS Google Scholar
Essenberg, M., Stoessl, A. & Stothers, J. B. (1985). J. Chem. Soc. Chem. Commun. 9, 556–557. CrossRef Web of Science Google Scholar
Oxford Diffraction (2009). CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stipanovic, R. D., Greenblatt, G. A., Beier, R. C. & Bell, A. A. (1981). Phytochemistry, 20, 729–730. CrossRef CAS Web of Science Google Scholar
Stipanovic, R. D., Wakelyn, P. J. & Bell, A. A. (1975). Phytochemistry, 14, 1041–1043. CrossRef CAS Web of Science Google Scholar
Suzuki, H., Yasuda, S. & Hanzawa, M. (1972). Mokuzai Gakkaishi, 18, 617–622. 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.
The title compound, C16H20O3, LCME is a sesquiterpene isolated from foliar tissues of the cotton plant. Its biosynthesis is induced in response to infection by the bacterial plant pathogen, Xanthomonas campestris pv. malvacearum; the latter is the causal agent of bacterial blight, and LCME exhibits antibacterial activity against this pathogen. LCME was originally isolated from Ulmus laciniata Mayr (Suzuki et al., 1972), but the proposed structure was incorrect. Subsequently, it was isolated together with lacinilene C from frost–killed cotton bracts (Gossypium species) and its structure was revised (Stipanovic et al., 1975). LCME is produced by autoxidation of 2–hydroxy–7–methoxycadalene, which also occurs in cotton plant foliage (Stipanovic et al., 1981). The biosynthesis was first elucidated by Essenberg et al. (1985). However, lacinilene C (the un–methylated derivative of lacinilene C 7–methyl ether) isolated from cotton tissues is optically active, which indicates it is the product of enzymatic transformation of 2,7–dihydroxycadalene (Essenberg et al., 1982). The conformation of the title molecule and numbering scheme of atoms is shown in Fig. 1. The atoms of the phenyl ring (C1–C4/C9/C10) are ideal planar with a r.m.s. = 0.0085 Å. In the second ring, the atoms C5–C7/C9/C10 lie in an ideal plane with a r.m.s. = 0.0313 Å, and the deviation from planarity of atom C8 is equal to 0.386 (3) Å. The dihedral angle between these planes is equal to 170.2 (1)°. The hydroxy group O3 and the methyl group C12 are oriented equatorially and axially to the second ring, respectively. In the crystal structure, the centrosymmetric dimers are formed through pairs of O3—H3···O2i classical hydrogen bonds. Weak non–classical hydrogen bonds between C13—H13B···O2ii of the centrosymmetric dimers associate into columns by translation along the c axis (Fig. 2). Symmetry codes: (i) -x+1,-y+1,-z+2; (ii) x, y, z-1. The columns form a crystal structure with a packing factor 0.66.