organic compounds
(4R,5R,6S,7R,8S,9R,10S,13S)-7,8β-Epoxymomilactone-A
aUniversity College of Pharmacy, University of the Punjab, Lahore 54590, Pakistan, bUniversity of Sargodha, Department of Physics, Sargodha, Pakistan, and cGovernment College University, Department of Chemistry, Lahore, Pakistan
*Correspondence e-mail: dmntahir_uos@yahoo.com
The title compound, C20H26O4, was extracted from Leucas Urticifolia, a wild Lamiaceae herb distributed in the Punjab, Baluchistan, Sindh and the Rajputana desert of Pakistan. The plant is utilized for various medicinal applications by the local community. The title compound is based on the pimarane–diterpene skeleton. The molecule exhibits an epoxy ring fused to momilactone-A, leading to a pentacyclic molecular structure. The was assigned by comparison with the of momilactone, but needs further verification. The is governed by four intermolecular hydrogen-bond interactions of the C—H⋯O type.
Related literature
For related literature, see: Bhattecharjee (2004); Germain & Deslongchamps (2002); Kato et al. (1973); Kiritikhar & Basu (2005); Misra et al. (1992, 1993, 1995).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2007); cell APEX2; data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON.
Supporting information
10.1107/S1600536808010556/im2057sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808010556/im2057Isup2.hkl
Leucas Urticaefolia was collected from the hills of Khanaspur, Pakistan. The plants were separated into stems (1.03 kg), inflorescence (256.56 g), leaves (812.34 g) and roots (421.34 g). Each of these fractions was dried under shade, powdered and extracted sequentially at room temperature for 72 h in each of the solvents such as hexane, chloroform, ethanol and water. Solvents were removed under reduced pressure. Each extract was extracted successively with n-hexane, chloroform, methanol and water as
in increasing order of polarity. Aluminium sheets precoated with silica gel 60 F254 (0.2 mm thick, E Merck) were used for TLC. was carried out on silica gel, 70–230 mesh. The title compound was taken from the water extract of the leaves.All H-atoms were found in Fourier synthesis and refined initially. However H atoms positioned geometrically resulted in the same values of
parameters.In final
the coordinates of H-atoms connected to C16 were refined. The rest of H-atoms were positioned geometrically, with C-H = 0.93, 0.97, 0.96 Å for C15, methylene and methyl C-atoms and constrained to ride on their parent atoms. The thermal parameter of methyl H-atoms was taken 1.5 times while for all other H-atoms it was taken 1.2 times of the parent atoms.Data collection: APEX2 (Bruker, 2007); cell
APEX2 (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).C20H26O4 | F(000) = 712 |
Mr = 330.41 | Dx = 1.248 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 1295 reflections |
a = 6.3996 (7) Å | θ = 1.6–28.6° |
b = 13.1759 (3) Å | µ = 0.09 mm−1 |
c = 20.854 (1) Å | T = 296 K |
V = 1758.4 (2) Å3 | Needle, colourless |
Z = 4 | 0.25 × 0.10 × 0.09 mm |
Bruker Kappa APEX2 CCD diffractometer | 2635 independent reflections |
Radiation source: fine-focus sealed tube | 1202 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.075 |
Detector resolution: 7.30 pixels mm-1 | θmax = 28.9°, θmin = 2.5° |
ω scans | h = −8→8 |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | k = −17→14 |
Tmin = 0.980, Tmax = 0.990 | l = −28→28 |
19288 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.117 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0443P)2 + 0.0772P] where P = (Fo2 + 2Fc2)/3 |
2635 reflections | (Δ/σ)max < 0.001 |
223 parameters | Δρmax = 0.14 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C20H26O4 | V = 1758.4 (2) Å3 |
Mr = 330.41 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 6.3996 (7) Å | µ = 0.09 mm−1 |
b = 13.1759 (3) Å | T = 296 K |
c = 20.854 (1) Å | 0.25 × 0.10 × 0.09 mm |
Bruker Kappa APEX2 CCD diffractometer | 2635 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 1202 reflections with I > 2σ(I) |
Tmin = 0.980, Tmax = 0.990 | Rint = 0.075 |
19288 measured reflections |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.117 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.14 e Å−3 |
2635 reflections | Δρmin = −0.18 e Å−3 |
223 parameters |
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. The low data parameter ratio is due to the small size of the crystal as well as to the absence of heavy atoms. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.2901 (4) | 0.5384 (2) | 0.77739 (11) | 0.1276 (11) | |
O2 | 0.6901 (4) | 0.54820 (17) | 0.70678 (11) | 0.0895 (7) | |
O3 | 0.6511 (3) | 0.64702 (13) | 0.62196 (9) | 0.0641 (5) | |
O4 | 0.4101 (3) | 0.82859 (12) | 0.50957 (8) | 0.0624 (5) | |
C1 | 0.0673 (4) | 0.7697 (2) | 0.70647 (13) | 0.0687 (8) | |
H1A | −0.0511 | 0.7524 | 0.6796 | 0.082* | |
H1B | 0.0347 | 0.8324 | 0.7288 | 0.082* | |
C2 | 0.1031 (5) | 0.6849 (2) | 0.75567 (14) | 0.0848 (10) | |
H2A | 0.1551 | 0.7159 | 0.7947 | 0.102* | |
H2B | −0.0316 | 0.6551 | 0.7657 | 0.102* | |
C3 | 0.2466 (5) | 0.6019 (3) | 0.73828 (15) | 0.0739 (9) | |
C4 | 0.3374 (5) | 0.5948 (2) | 0.67075 (12) | 0.0577 (7) | |
C5 | 0.2923 (4) | 0.68587 (18) | 0.62796 (11) | 0.0499 (7) | |
H5 | 0.1673 | 0.6716 | 0.6024 | 0.060* | |
C6 | 0.4805 (4) | 0.68849 (19) | 0.58381 (11) | 0.0553 (7) | |
H6 | 0.4545 | 0.6434 | 0.5473 | 0.066* | |
C7 | 0.5436 (4) | 0.7907 (2) | 0.55901 (11) | 0.0535 (7) | |
H7 | 0.6937 | 0.8028 | 0.5537 | 0.064* | |
C8 | 0.4140 (4) | 0.87944 (18) | 0.57182 (11) | 0.0462 (6) | |
C9 | 0.2192 (4) | 0.86667 (18) | 0.61280 (11) | 0.0459 (6) | |
H9 | 0.1100 | 0.8397 | 0.5846 | 0.055* | |
C10 | 0.2590 (4) | 0.78561 (18) | 0.66466 (11) | 0.0449 (6) | |
C11 | 0.1424 (5) | 0.9704 (2) | 0.63641 (13) | 0.0654 (8) | |
H11A | 0.0037 | 0.9639 | 0.6547 | 0.078* | |
H11B | 0.2354 | 0.9960 | 0.6694 | 0.078* | |
C12 | 0.1373 (5) | 1.0436 (2) | 0.57995 (14) | 0.0672 (8) | |
H12A | 0.0686 | 1.1058 | 0.5932 | 0.081* | |
H12B | 0.0551 | 1.0139 | 0.5457 | 0.081* | |
C13 | 0.3552 (5) | 1.06931 (19) | 0.55425 (14) | 0.0631 (8) | |
C14 | 0.5096 (4) | 0.98319 (19) | 0.57133 (14) | 0.0608 (8) | |
H14A | 0.6235 | 0.9839 | 0.5406 | 0.073* | |
H14B | 0.5684 | 0.9968 | 0.6133 | 0.073* | |
C15 | 0.3421 (6) | 1.0775 (3) | 0.48310 (17) | 0.0956 (12) | |
H15 | 0.3070 | 1.0178 | 0.4619 | 0.115* | |
C16 | 0.3716 (10) | 1.1536 (5) | 0.4474 (3) | 0.171 (3) | |
C17 | 0.4321 (6) | 1.1672 (2) | 0.5862 (2) | 0.1304 (16) | |
H17A | 0.4403 | 1.1573 | 0.6317 | 0.196* | |
H17B | 0.3363 | 1.2213 | 0.5770 | 0.196* | |
H17C | 0.5679 | 1.1843 | 0.5699 | 0.196* | |
C18 | 0.5739 (5) | 0.5923 (2) | 0.67153 (14) | 0.0635 (8) | |
C19 | 0.2609 (7) | 0.4944 (2) | 0.64183 (16) | 0.1028 (13) | |
H19A | 0.1109 | 0.4939 | 0.6409 | 0.154* | |
H19B | 0.3099 | 0.4389 | 0.6675 | 0.154* | |
H19C | 0.3139 | 0.4876 | 0.5990 | 0.154* | |
C20 | 0.4458 (4) | 0.81615 (19) | 0.70649 (11) | 0.0535 (7) | |
H20A | 0.5665 | 0.8259 | 0.6799 | 0.080* | |
H20B | 0.4735 | 0.7635 | 0.7372 | 0.080* | |
H20C | 0.4143 | 0.8782 | 0.7286 | 0.080* | |
H16A | 0.378 (5) | 1.143 (2) | 0.4045 (13) | 0.080* | |
H16B | 0.397 (5) | 1.214 (2) | 0.4727 (13) | 0.080* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.124 (2) | 0.153 (2) | 0.1054 (19) | 0.0407 (19) | 0.0296 (18) | 0.0790 (18) |
O2 | 0.0755 (17) | 0.0982 (17) | 0.0950 (15) | 0.0171 (13) | −0.0114 (13) | 0.0445 (13) |
O3 | 0.0669 (13) | 0.0666 (12) | 0.0588 (11) | 0.0172 (10) | 0.0070 (11) | 0.0134 (10) |
O4 | 0.0828 (15) | 0.0634 (12) | 0.0409 (10) | 0.0064 (10) | −0.0036 (9) | 0.0013 (9) |
C1 | 0.0527 (19) | 0.082 (2) | 0.0713 (19) | −0.0007 (16) | 0.0122 (16) | 0.0101 (18) |
C2 | 0.072 (2) | 0.105 (3) | 0.078 (2) | −0.011 (2) | 0.0138 (18) | 0.028 (2) |
C3 | 0.061 (2) | 0.084 (2) | 0.077 (2) | −0.0048 (19) | −0.0003 (18) | 0.0255 (19) |
C4 | 0.063 (2) | 0.0541 (17) | 0.0558 (18) | −0.0116 (16) | −0.0113 (16) | 0.0105 (14) |
C5 | 0.0542 (18) | 0.0468 (16) | 0.0487 (14) | −0.0096 (13) | −0.0153 (13) | 0.0047 (13) |
C6 | 0.074 (2) | 0.0522 (18) | 0.0399 (14) | 0.0088 (15) | −0.0037 (15) | −0.0001 (13) |
C7 | 0.0567 (18) | 0.0583 (18) | 0.0455 (15) | 0.0058 (14) | 0.0061 (14) | 0.0049 (13) |
C8 | 0.0454 (16) | 0.0496 (16) | 0.0435 (14) | 0.0008 (13) | −0.0021 (13) | −0.0003 (12) |
C9 | 0.0398 (16) | 0.0517 (16) | 0.0462 (14) | 0.0009 (12) | −0.0024 (13) | 0.0008 (13) |
C10 | 0.0387 (15) | 0.0545 (17) | 0.0415 (13) | −0.0029 (12) | −0.0001 (13) | −0.0006 (13) |
C11 | 0.064 (2) | 0.0643 (18) | 0.0679 (19) | 0.0148 (17) | 0.0105 (16) | −0.0003 (16) |
C12 | 0.069 (2) | 0.0561 (18) | 0.076 (2) | 0.0125 (16) | 0.0017 (18) | 0.0033 (15) |
C13 | 0.059 (2) | 0.0462 (18) | 0.084 (2) | −0.0008 (15) | −0.0015 (17) | 0.0065 (16) |
C14 | 0.0503 (18) | 0.0530 (18) | 0.0792 (19) | −0.0029 (14) | −0.0015 (17) | 0.0058 (15) |
C15 | 0.098 (3) | 0.087 (3) | 0.102 (3) | 0.030 (2) | 0.018 (2) | 0.046 (2) |
C16 | 0.207 (6) | 0.156 (5) | 0.150 (5) | 0.099 (5) | 0.068 (5) | 0.061 (4) |
C17 | 0.125 (4) | 0.053 (2) | 0.213 (5) | −0.012 (2) | −0.034 (3) | −0.014 (3) |
C18 | 0.075 (2) | 0.0528 (18) | 0.0624 (19) | 0.0052 (17) | −0.0019 (19) | 0.0097 (16) |
C19 | 0.132 (3) | 0.054 (2) | 0.123 (3) | −0.0241 (19) | −0.047 (3) | 0.0172 (19) |
C20 | 0.0569 (18) | 0.0573 (17) | 0.0462 (14) | −0.0039 (14) | −0.0069 (13) | −0.0065 (13) |
O1—C3 | 1.201 (3) | C9—C10 | 1.541 (3) |
O2—C18 | 1.196 (3) | C9—H9 | 0.9800 |
O3—C18 | 1.354 (3) | C10—C20 | 1.534 (3) |
O3—C6 | 1.457 (3) | C11—C12 | 1.523 (3) |
O4—C7 | 1.429 (3) | C11—H11A | 0.9700 |
O4—C8 | 1.461 (3) | C11—H11B | 0.9700 |
C1—C10 | 1.519 (3) | C12—C13 | 1.532 (4) |
C1—C2 | 1.534 (4) | C12—H12A | 0.9700 |
C1—H1A | 0.9700 | C12—H12B | 0.9700 |
C1—H1B | 0.9700 | C13—C15 | 1.490 (4) |
C2—C3 | 1.474 (4) | C13—C17 | 1.533 (4) |
C2—H2A | 0.9700 | C13—C14 | 1.546 (4) |
C2—H2B | 0.9700 | C14—H14A | 0.9700 |
C3—C4 | 1.526 (4) | C14—H14B | 0.9700 |
C4—C18 | 1.514 (4) | C15—C16 | 1.263 (6) |
C4—C5 | 1.523 (3) | C15—H15 | 0.9300 |
C4—C19 | 1.534 (4) | C16—H16A | 0.91 (2) |
C5—C6 | 1.516 (4) | C16—H16B | 0.97 (2) |
C5—C10 | 1.536 (3) | C17—H17A | 0.9600 |
C5—H5 | 0.9800 | C17—H17B | 0.9600 |
C6—C7 | 1.499 (3) | C17—H17C | 0.9600 |
C6—H6 | 0.9800 | C19—H19A | 0.9600 |
C7—C8 | 1.458 (3) | C19—H19B | 0.9600 |
C7—H7 | 0.9800 | C19—H19C | 0.9600 |
C8—C14 | 1.498 (3) | C20—H20A | 0.9600 |
C8—C9 | 1.521 (3) | C20—H20B | 0.9600 |
C9—C11 | 1.533 (3) | C20—H20C | 0.9600 |
C18—O3—C6 | 110.1 (2) | C20—C10—C5 | 113.6 (2) |
C7—O4—C8 | 60.57 (15) | C1—C10—C9 | 111.4 (2) |
C10—C1—C2 | 111.3 (2) | C20—C10—C9 | 110.3 (2) |
C10—C1—H1A | 109.4 | C5—C10—C9 | 105.44 (18) |
C2—C1—H1A | 109.4 | C12—C11—C9 | 108.9 (2) |
C10—C1—H1B | 109.4 | C12—C11—H11A | 109.9 |
C2—C1—H1B | 109.4 | C9—C11—H11A | 109.9 |
H1A—C1—H1B | 108.0 | C12—C11—H11B | 109.9 |
C3—C2—C1 | 118.0 (3) | C9—C11—H11B | 109.9 |
C3—C2—H2A | 107.8 | H11A—C11—H11B | 108.3 |
C1—C2—H2A | 107.8 | C11—C12—C13 | 113.0 (2) |
C3—C2—H2B | 107.8 | C11—C12—H12A | 109.0 |
C1—C2—H2B | 107.8 | C13—C12—H12A | 109.0 |
H2A—C2—H2B | 107.1 | C11—C12—H12B | 109.0 |
O1—C3—C2 | 119.6 (3) | C13—C12—H12B | 109.0 |
O1—C3—C4 | 119.7 (3) | H12A—C12—H12B | 107.8 |
C2—C3—C4 | 120.6 (3) | C15—C13—C12 | 108.3 (3) |
C18—C4—C5 | 102.3 (2) | C15—C13—C17 | 112.9 (3) |
C18—C4—C3 | 111.8 (2) | C12—C13—C17 | 109.0 (3) |
C5—C4—C3 | 114.9 (2) | C15—C13—C14 | 108.6 (2) |
C18—C4—C19 | 107.7 (3) | C12—C13—C14 | 109.8 (2) |
C5—C4—C19 | 112.9 (2) | C17—C13—C14 | 108.2 (3) |
C3—C4—C19 | 107.1 (3) | C8—C14—C13 | 114.2 (2) |
C6—C5—C4 | 102.9 (2) | C8—C14—H14A | 108.7 |
C6—C5—C10 | 113.2 (2) | C13—C14—H14A | 108.7 |
C4—C5—C10 | 114.10 (19) | C8—C14—H14B | 108.7 |
C6—C5—H5 | 108.8 | C13—C14—H14B | 108.7 |
C4—C5—H5 | 108.8 | H14A—C14—H14B | 107.6 |
C10—C5—H5 | 108.8 | C16—C15—C13 | 129.5 (5) |
O3—C6—C7 | 108.9 (2) | C16—C15—H15 | 115.2 |
O3—C6—C5 | 104.77 (18) | C13—C15—H15 | 115.2 |
C7—C6—C5 | 116.4 (2) | C15—C16—H16A | 118 (2) |
O3—C6—H6 | 108.9 | C15—C16—H16B | 111 (2) |
C7—C6—H6 | 108.9 | H16A—C16—H16B | 131 (3) |
C5—C6—H6 | 108.9 | C13—C17—H17A | 109.5 |
O4—C7—C8 | 60.81 (15) | C13—C17—H17B | 109.5 |
O4—C7—C6 | 113.7 (2) | H17A—C17—H17B | 109.5 |
C8—C7—C6 | 120.3 (2) | C13—C17—H17C | 109.5 |
O4—C7—H7 | 116.7 | H17A—C17—H17C | 109.5 |
C8—C7—H7 | 116.7 | H17B—C17—H17C | 109.5 |
C6—C7—H7 | 116.7 | O2—C18—O3 | 120.1 (3) |
C7—C8—O4 | 58.63 (14) | O2—C18—C4 | 129.7 (3) |
C7—C8—C14 | 119.9 (2) | O3—C18—C4 | 110.2 (3) |
O4—C8—C14 | 114.8 (2) | C4—C19—H19A | 109.5 |
C7—C8—C9 | 118.7 (2) | C4—C19—H19B | 109.5 |
O4—C8—C9 | 115.74 (19) | H19A—C19—H19B | 109.5 |
C14—C8—C9 | 116.1 (2) | C4—C19—H19C | 109.5 |
C8—C9—C11 | 110.2 (2) | H19A—C19—H19C | 109.5 |
C8—C9—C10 | 109.59 (19) | H19B—C19—H19C | 109.5 |
C11—C9—C10 | 116.4 (2) | C10—C20—H20A | 109.5 |
C8—C9—H9 | 106.7 | C10—C20—H20B | 109.5 |
C11—C9—H9 | 106.7 | H20A—C20—H20B | 109.5 |
C10—C9—H9 | 106.7 | C10—C20—H20C | 109.5 |
C1—C10—C20 | 109.82 (19) | H20A—C20—H20C | 109.5 |
C1—C10—C5 | 106.3 (2) | H20B—C20—H20C | 109.5 |
C10—C1—C2—C3 | −30.0 (4) | C2—C1—C10—C20 | −60.7 (3) |
C1—C2—C3—O1 | 174.5 (3) | C2—C1—C10—C5 | 62.5 (3) |
C1—C2—C3—C4 | −6.6 (4) | C2—C1—C10—C9 | 176.9 (2) |
O1—C3—C4—C18 | −57.0 (4) | C6—C5—C10—C1 | −179.6 (2) |
C2—C3—C4—C18 | 124.1 (3) | C4—C5—C10—C1 | −62.4 (3) |
O1—C3—C4—C5 | −173.1 (3) | C6—C5—C10—C20 | −58.8 (3) |
C2—C3—C4—C5 | 8.0 (4) | C4—C5—C10—C20 | 58.5 (3) |
O1—C3—C4—C19 | 60.7 (4) | C6—C5—C10—C9 | 62.1 (3) |
C2—C3—C4—C19 | −118.2 (3) | C4—C5—C10—C9 | 179.3 (2) |
C18—C4—C5—C6 | 28.8 (2) | C8—C9—C10—C1 | −179.5 (2) |
C3—C4—C5—C6 | 150.2 (2) | C11—C9—C10—C1 | 54.6 (3) |
C19—C4—C5—C6 | −86.7 (3) | C8—C9—C10—C20 | 58.3 (2) |
C18—C4—C5—C10 | −94.2 (3) | C11—C9—C10—C20 | −67.5 (3) |
C3—C4—C5—C10 | 27.2 (3) | C8—C9—C10—C5 | −64.7 (2) |
C19—C4—C5—C10 | 150.3 (3) | C11—C9—C10—C5 | 169.5 (2) |
C18—O3—C6—C7 | 145.2 (2) | C8—C9—C11—C12 | 47.6 (3) |
C18—O3—C6—C5 | 20.1 (3) | C10—C9—C11—C12 | 173.2 (2) |
C4—C5—C6—O3 | −30.2 (2) | C9—C11—C12—C13 | −67.5 (3) |
C10—C5—C6—O3 | 93.4 (2) | C11—C12—C13—C15 | 142.6 (3) |
C4—C5—C6—C7 | −150.5 (2) | C11—C12—C13—C17 | −94.1 (3) |
C10—C5—C6—C7 | −26.9 (3) | C11—C12—C13—C14 | 24.2 (3) |
C8—O4—C7—C6 | 112.7 (2) | C7—C8—C14—C13 | 153.1 (2) |
O3—C6—C7—O4 | 166.57 (18) | O4—C8—C14—C13 | 86.4 (3) |
C5—C6—C7—O4 | −75.4 (3) | C9—C8—C14—C13 | −52.9 (3) |
O3—C6—C7—C8 | −124.6 (2) | C15—C13—C14—C8 | −84.6 (3) |
C5—C6—C7—C8 | −6.5 (3) | C12—C13—C14—C8 | 33.6 (3) |
C6—C7—C8—O4 | −101.9 (3) | C17—C13—C14—C8 | 152.5 (3) |
O4—C7—C8—C14 | −102.5 (3) | C12—C13—C15—C16 | 115.8 (5) |
C6—C7—C8—C14 | 155.6 (2) | C17—C13—C15—C16 | −5.0 (6) |
O4—C7—C8—C9 | 104.2 (2) | C14—C13—C15—C16 | −125.0 (5) |
C6—C7—C8—C9 | 2.3 (3) | C6—O3—C18—O2 | 176.6 (3) |
C7—O4—C8—C14 | 111.2 (2) | C6—O3—C18—C4 | −1.0 (3) |
C7—O4—C8—C9 | −109.3 (2) | C5—C4—C18—O2 | 164.5 (3) |
C7—C8—C9—C11 | 163.7 (2) | C3—C4—C18—O2 | 41.0 (4) |
O4—C8—C9—C11 | −129.6 (2) | C19—C4—C18—O2 | −76.3 (4) |
C14—C8—C9—C11 | 9.4 (3) | C5—C4—C18—O3 | −18.1 (3) |
C7—C8—C9—C10 | 34.3 (3) | C3—C4—C18—O3 | −141.6 (2) |
O4—C8—C9—C10 | 101.1 (2) | C19—C4—C18—O3 | 101.0 (3) |
C14—C8—C9—C10 | −119.9 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2B···O2i | 0.97 | 2.58 | 3.356 (5) | 137 |
C7—H7···O4ii | 0.98 | 2.58 | 3.164 (4) | 118 |
C11—H11A···O1iii | 0.97 | 2.55 | 3.420 (5) | 149 |
C14—H14B···O1iv | 0.97 | 2.52 | 3.486 (5) | 178 |
Symmetry codes: (i) x−1, y, z; (ii) x+1/2, −y+3/2, −z+1; (iii) −x, y+1/2, −z+3/2; (iv) −x+1, y+1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C20H26O4 |
Mr | 330.41 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 296 |
a, b, c (Å) | 6.3996 (7), 13.1759 (3), 20.854 (1) |
V (Å3) | 1758.4 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.25 × 0.10 × 0.09 |
Data collection | |
Diffractometer | Bruker Kappa APEX2 CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.980, 0.990 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 19288, 2635, 1202 |
Rint | 0.075 |
(sin θ/λ)max (Å−1) | 0.679 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.117, 1.03 |
No. of reflections | 2635 |
No. of parameters | 223 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.14, −0.18 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003), WinGX (Farrugia, 1999) and PLATON (Spek, 2003).
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2B···O2i | 0.97 | 2.58 | 3.356 (5) | 137 |
C7—H7···O4ii | 0.98 | 2.58 | 3.164 (4) | 118 |
C11—H11A···O1iii | 0.97 | 2.55 | 3.420 (5) | 149 |
C14—H14B···O1iv | 0.97 | 2.52 | 3.486 (5) | 178 |
Symmetry codes: (i) x−1, y, z; (ii) x+1/2, −y+3/2, −z+1; (iii) −x, y+1/2, −z+3/2; (iv) −x+1, y+1/2, −z+3/2. |
Acknowledgements
The authors acknowledge the Higher Education Commision, Islamabad, Pakistan, for the purchase of the Kappa APEX2 CCD diffractometer.
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.
Leucas urticaefolia is a wild Lamiaceae herb distributed in the Punjab, Baluchistan, Sindh and Rajputana desert of Pakistan. At Gomawal in Baluchistan, the plant is used as a cure for fever. It's local name in Gujerati is Kubo (Kiritikhar & Basu, 2005) and in Tilla Gogian of the Potohar region, it is known as Goma or Guldora. The decoction of the leaves and apical shoots with gur is used locally as an abortifacient up to 3 months of pregnancy. Infusion of the flowers are used in skin diseases. It is also used to treat piles. Other plants of the genera are also used in local remedies, e.g, the flowers of Leucas cephalotes are used to treat cold and cough while the entire plant has stimulant and insecticidal properties (Bhattecharjee, S.K., 2004). No work has been recorded for Leucas Urticaefolia although other plants of the genera have shown biologically and physiologically interesting classes of compounds (Misra et al., 1992; Misra et al., 1993; Misra et al., 1995).
Momilactone was originally extracted from the seed husk (Kato et al., 1973). The crystal structure was determined and the assignment of the absolute configuration was performed by several spectroscopic techniques. Synthesis of racemic (±)-Momilactone A and a related structure has been reported (Germain & Deslongchamps, 2002). The title compound (I), C20H26O4, is related to Momilactone A differing by one additional epoxy ring system therefore resulting in a pentacyclic molecular skeleton. There are three six membered rings: A (C1 to C5, C10), B (C5 to C10) and C (C8,C9,C11 to C14). One five membered ring D (C4 to C6, O3, C18) with the lactone functional group is fused to ring A and ring B. The three membered epoxy ring E (C7, C8, O4) is fused to ring B in β-position. In analogy to the molecular structure of Momilactone the title compound was refined in the same absolute configuration with the chiral centers in the molecule being C4(R), C5(R), C6(S), C7(R), C8(S), C9(R), C10(S) and C13(S). Nevertheless, this configuration of course cannot be determined reliably using the experimental conditions of this investigation. Due to the methyl group attached to the common vertex of ring A and B at C10, these rings show an envelope conformation with C10 in an almost identical distance of -0.789 (4) Å from both planes. The dihedral angle between the planes (C1 to C5) and (C5 to C9) is 35.1 (2)° while the epoxy ring (C7, C8, O4) encloses dihedral angles of 39.8 (2)° and 74.9 (2)° with them, respectively. The puckering parameters (Cremer & Pople, 1975) for ring A and B are Q = 0.570 (3) Å and 0.584 (3) Å, θ = 119.8 (4)° and 122.1 (3)° and ϕ = 122.6 (4)° and 113.8 (4)°, respectively. Ring C exhibits a twist conformation with the planes (C8, C9, C12, C14) and (C11, C12, C13, C14) showing a dihedral angle of 51.1 (2)°. For ring D also an envelope conformation is observed with C5 at a distance of -0.485 (5) Å from the plane (C4, C18, O3, C6). The puckering parameters (Cremer & Pople, 1975) for ring C are Q = 0.724 (4) Å, θ = 96.3 (3)° and ϕ = 315.3 (3)°.
In (I), the bond lengths C3=O1 and C18=O2 have identical values [1.198 (4), 1.197 (4) Å]. The C=C bond length [C15 = C16] is 1.281 (7) Å, while the C—C bond distance for methyl C-atoms from the ring carbons have nearly same value of 1.537 (4) Å. These values are similar to the reported submitted (CCDC No. 172789) by Germain & Deslongchamps, 2002. In the crystal structure, the asymmetric unit is linked to four neighboring molecules through intermolecular C—H···O hydrogen bonds (Table 1). These H-bonds (Fig. 1) seem to be effective in the stabilization of the structure. There is no significant π-π interaction.