(−)-Kolavenic acid

Julio Zukerman-Schpector; Lucas Sousa Madureira; Gisele B Messiano; Lucia M X Lopes; Edward R T Tiekink

doi:10.1107/S1600536808014402

. 2008 May 17;64(Pt 6):o1114. doi: 10.1107/S1600536808014402

(−)-Kolavenic acid

Julio Zukerman-Schpector ^a,^*, Lucas Sousa Madureira ^a, Gisele B Messiano ^b, Lucia M X Lopes ^b, Edward R T Tiekink ^c

PMCID: PMC2961406 PMID: 21202625

Abstract

In the two, almost identical, molecules in the asymmetric unit of the title compound [systematic name: (E)-3-methyl-5-(1,2,4a,5-tetramethyl-1,2,3,4,4a,7,8,8a-octahydronaphthalen-1-yl)pent-2-enoic acid], C₂₀H₃₂O₂, the rings are trans fused. The cyclohexane ring has a chair conformation and the cyclohexene ring a distorted half-boat conformation. The two independent molecules are connected into a dimer via O—H⋯O hydrogen bonds. The dimers are associated into supramolecular chains along c via C—H⋯O contacts.

Related literature

For related structures, see: Puliti & Mattia (2000 ▶). For related literature, see: Lopes et al. (1987 ▶); Bomm et al. (1999 ▶); Messiano et al. (2008 ▶); Nascimento et al. (2004 ▶). For ring structure analysis, see: Cremer & Pople (1975 ▶); Spek (2003 ▶).

Experimental

Crystal data

C₂₀H₃₂O₂
M _r = 304.46
Orthorhombic,
a = 12.5122 (3) Å
b = 15.5439 (4) Å
c = 19.1969 (4) Å
V = 3733.57 (15) Å³
Z = 8
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 291 (2) K
0.42 × 0.20 × 0.18 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: none
48366 measured reflections
6240 independent reflections
3146 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.134
S = 1.00
6240 reflections
407 parameters
H-atom parameters constrained
Δρ_max = 0.11 e Å⁻³
Δρ_min = −0.12 e Å⁻³

Data collection: APEX2, COSMO and BIS (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808014402/ng2455sup1.cif

e-64-o1114-sup1.cif^{(34KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808014402/ng2455Isup2.hkl

e-64-o1114-Isup2.hkl^{(299.3KB, 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
O101—H101⋯O202	0.82	1.82	2.625 (3)	168
O201—H201⋯O102	0.82	1.90	2.700 (2)	164
C212—H21R⋯O202ⁱ	0.96	2.60	3.519 (4)	159

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Symmetry code: (i) Inline graphic .

Acknowledgments

We thank FAPESP, CNPq and CAPES for financial support. Professor R. A. Burrow of the Federal University of Santa Maria is gratefully acknowledged for the collection of the intensity data.

supplementary crystallographic information

Comment

The title compound (I), Fig. 1, was studied as a part of an on-going screen of natural insecticides from Aristolochia species, which has become a promising route for the discovery of new compounds and/or botanical preparations which could be used in crop protection against Anticarsia gemmatalis H. (Lepidoptera: Noctuidae). Larvae of this insect represent the major defoliator pest of soybean crops in Brazil.

There are two almost identical independent molecules in the asymmetric unit, in fact superimposition of them, excluding H atoms, gives a rmsd of 0.016 Å (Spek, 2003). The major difference between the molecules is manifested in the relative orientations of the carboxylic acid residues so that in one molecule the carbonyl-O102 atom is syn to the methyl-C118 group whereas the opposite is true for the second independent molecule. In each molecule the rings are trans fused and the cyclohexane ring is in an almost undistorted chair conformation. The cyclohexene ring is in a distorted half-boat conformation, the ring-puckering parameters (Cremer & Pople, 1975) are q₂ = 0.400 (3) Å (0.406 (3) Å for the second molecule), q₃ = -0.341 (3) Å (-0.336 (3) Å), Q = 0.525 (2) ° (0.527 (2) °), and φ₂ = 106.6 (4)° (107.3 (4) °). The absolute configuration was established based on the [α_D] = -41.1° (c 1.0, CHCl₃) and the results reported in Bomm et al. (1999).

The independent molecules in (I) are connected via cooperative O—H···O contacts that form the eight-membered {···H—O—C=O}₂ synthon, Table 1. The resultant dimeric aggregates are linked into a supramolecular chain along the c-direction via C212—H21R···O202 contacts, Fig. 2.

Experimental

Compound (I), (-)-kolavenic acid, was obtained from the hexane extract of the roots of Aristolochia malmeana Hoehne (Aristolochiaceae). Colorless crystals were obtained from the slow evaporation of a MeOH solution of (I) held at 283 K; m.p. 370–371 K. NMR (CDCl₃, p.p.m.): δ 0.93 (1H, t, w_1/2 = 7.0 Hz, H-1_a), 1.36 (1H, m, H-1_b), 1.99 (1H, m, H-2_a), 1.94 (1H, m, H-2_b), 5.13 (1H, br s, H-3), 1.66 (1H, dt, J = 13.0, 3.0 Hz, H-6_a), 1.12 (1H, ddd, J = 13.0, 12.0, 4.2 Hz, H-6_b), 1.33 (1H, m, H-7a), 1.39 (1H, m, H-7_b), 1.37 (1H, m, H-8), 1.27 (1H, dd, J = 12.0, 1.5 Hz, H-10), 1.34 (1H, ddd, J = 14.0, 13.0, 4.5 Hz, H-11_a), 1.48 (1H, ddd, J = 14.0, 12.5, 5.0 Hz, H-11_b), 1.97 (1H, td, J = 13.0, 4.5 Hz, H-12_a), 1.90 (1H, ddd, J = 13.0, 12.5, 5.0 Hz, H-12_b), 5.62 (1H, dq, J = 2.5, 1.0 Hz, H-14), 2.11 (3H, br d, J = 1.0 Hz, H-16), 0.76 (3H, d, J = 6.0 Hz, H-17), 1.53 (3H, br s, H-18), 0.94 (3H, s, H-19), 0.68 (3H, s, H-20). [α_D] = -41.1° in agreement with Bomm et al. (1999) and Messiano et al. (2008).