Dehydro-brachylaenolide: an eudesmane-type sesquiterpene lactone.

The three-ring eudesmanolide, C(15)H(16)O(3), is a natural product isolated from Dicoma anomala Sond. (Asteraceae). The compound contains an endo-exo cross conjugated methyl-enecyclo-hexenone ring with an envelope conformation trans-fused with cyclo-hexane and trans-annelated with an α-methyl-ene γ-lactone. The absolute structure was assigned by optical rotation measurements compared to those from the synthetic compound with known stereochemistry. The crystal packing is consolidated by C-H⋯O interactions.

Related literature

For NMR studies of this compound, see: Bohlmann & Zdero, (1982 ▶); Grass et al. (2004 ▶). For the chemical synthesis and confirmation of the absolute structure, see: Higuchi et al. (2003 ▶).

Experimental

Crystal data

C15H16O3

M = 244.28

Orthorhombic,

a = 9.5648 (6) Å

b = 11.1631 (6) Å

c = 11.5542 (6) Å

V = 1233.67 (12) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 150 (2) K

0.50 × 0.50 × 0.40 mm

Data collection

Oxford Diffraction Excalibur2 CCD diffractometer

Absorption correction: multi-scan (Blessing, 1995 ▶) T min = 0.909, T max = 0.963

12604 measured reflections

2294 independent reflections

1988 reflections with I > 2σ(I)

R int = 0.016

Refinement

R[F 2 > 2σ(F 2)] = 0.033

wR(F 2) = 0.095

S = 1.05

2294 reflections

163 parameters

H-atom parameters constrained

Δρmax = 0.31 e Å−3

Δρmin = −0.21 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2006 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: PLATON (Spek, 2003 ▶) and WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808042402/bi2330sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808042402/bi2330Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C15H16O3	F(000) = 520
Mr = 244.28	Dx = 1.315 Mg m−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 8167 reflections
a = 9.5648 (6) Å	θ = 4.0–31.8°
b = 11.1631 (6) Å	µ = 0.09 mm−1
c = 11.5542 (6) Å	T = 150 K
V = 1233.67 (12) Å3	Block, colourless
Z = 4	0.50 × 0.50 × 0.40 mm

Oxford Diffraction Excalibur2 CCD diffractometer	2294 independent reflections
Radiation source: fine-focus sealed tube	1988 reflections with I > 2σ(I)
graphite	Rint = 0.016
ω scans	θmax = 31.9°, θmin = 4.0°
Absorption correction: multi-scan (Blessing, 1995)	h = −13→13
Tmin = 0.909, Tmax = 0.963	k = −15→16
12604 measured reflections	l = −16→17

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095	H-atom parameters constrained
S = 1.05	w = 1/[σ2(Fo2) + (0.0708P)2] where P = (Fo2 + 2Fc2)/3
2294 reflections	(Δ/σ)max = 0.001
163 parameters	Δρmax = 0.31 e Å−3
0 restraints	Δρmin = −0.21 e Å−3

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.

	x	y	z	Uiso*/Ueq
C4	0.86180 (14)	0.08184 (11)	1.24094 (11)	0.0237 (2)
O2	0.87541 (10)	0.20733 (7)	1.00141 (7)	0.0245 (2)
C7	1.04877 (12)	0.07144 (11)	0.94161 (10)	0.0210 (2)
H7	1.1253	0.1211	0.9714	0.025*
C8	1.10043 (14)	−0.05782 (12)	0.94001 (11)	0.0246 (3)
H8A	1.1798	−0.0657	0.8883	0.029*
H8B	1.0268	−0.1109	0.9136	0.029*
C9	1.14347 (13)	−0.08979 (11)	1.06503 (11)	0.0245 (2)
H9A	1.1717	−0.1732	1.0675	0.029*
H9B	1.2238	−0.0416	1.0866	0.029*
O3	0.85244 (12)	0.31953 (9)	0.84156 (9)	0.0372 (3)
C14	0.90759 (14)	−0.16252 (11)	1.13671 (12)	0.0270 (3)
H14A	0.8694	−0.1540	1.0603	0.041*
H14B	0.8354	−0.1493	1.1930	0.041*
H14C	0.9447	−0.2419	1.1458	0.041*
C6	0.92565 (13)	0.08521 (10)	1.02492 (10)	0.0197 (2)
H6	0.8525	0.0278	1.0037	0.024*
C3	0.90807 (15)	0.04878 (12)	1.36063 (11)	0.0274 (3)
O1	0.84841 (13)	0.08529 (10)	1.44767 (9)	0.0385 (3)
C11	0.98993 (14)	0.13415 (11)	0.83767 (11)	0.0234 (2)
C1	1.08111 (15)	−0.08814 (12)	1.27617 (12)	0.0279 (3)
H1	1.1553	−0.1409	1.2867	0.033*
C5	0.97025 (12)	0.06224 (10)	1.14800 (10)	0.0197 (2)
H5	1.0491	0.1156	1.1647	0.024*
C10	1.02589 (13)	−0.06954 (10)	1.15444 (10)	0.0213 (2)
C15	0.73174 (15)	0.12080 (12)	1.22442 (14)	0.0321 (3)
H15A	0.6708	0.1272	1.2868	0.039*
H15B	0.7019	0.1416	1.1505	0.039*
C13	1.00061 (16)	0.11111 (13)	0.72528 (11)	0.0303 (3)
H13A	0.9501	0.1564	0.6722	0.036*
H13B	1.0586	0.0497	0.6996	0.036*
C12	0.89936 (14)	0.23105 (11)	0.88715 (11)	0.0263 (3)
C2	1.02875 (16)	−0.03277 (13)	1.36888 (11)	0.0304 (3)
H2	1.0696	−0.0460	1.4408	0.036*

	U11	U22	U33	U12	U13	U23
C4	0.0291 (6)	0.0164 (5)	0.0257 (5)	−0.0021 (5)	0.0069 (5)	0.0005 (4)
O2	0.0309 (5)	0.0174 (4)	0.0253 (4)	0.0031 (3)	0.0029 (4)	0.0023 (3)
C7	0.0202 (5)	0.0206 (5)	0.0221 (5)	−0.0010 (4)	0.0013 (4)	−0.0030 (4)
C8	0.0239 (6)	0.0254 (6)	0.0244 (5)	0.0037 (5)	0.0003 (5)	−0.0048 (5)
C9	0.0200 (5)	0.0245 (6)	0.0289 (6)	0.0036 (5)	−0.0014 (5)	−0.0027 (4)
O3	0.0499 (7)	0.0262 (5)	0.0356 (5)	0.0061 (5)	0.0000 (5)	0.0081 (4)
C14	0.0277 (6)	0.0168 (5)	0.0366 (6)	−0.0020 (5)	−0.0027 (5)	0.0014 (5)
C6	0.0195 (5)	0.0148 (5)	0.0248 (5)	0.0006 (4)	0.0012 (4)	−0.0001 (4)
C3	0.0330 (6)	0.0233 (6)	0.0259 (5)	−0.0079 (5)	0.0076 (5)	0.0017 (5)
O1	0.0493 (6)	0.0366 (6)	0.0297 (5)	−0.0062 (5)	0.0165 (5)	−0.0008 (4)
C11	0.0233 (6)	0.0207 (5)	0.0261 (5)	−0.0040 (4)	0.0015 (5)	0.0001 (4)
C1	0.0288 (6)	0.0252 (6)	0.0297 (6)	0.0015 (5)	−0.0043 (5)	0.0036 (5)
C5	0.0202 (5)	0.0171 (5)	0.0217 (5)	−0.0007 (4)	0.0021 (4)	−0.0002 (4)
C10	0.0212 (5)	0.0186 (5)	0.0241 (5)	0.0011 (4)	−0.0022 (4)	0.0000 (4)
C15	0.0310 (7)	0.0263 (6)	0.0391 (7)	0.0033 (5)	0.0129 (6)	0.0040 (6)
C13	0.0314 (6)	0.0337 (7)	0.0257 (6)	−0.0050 (6)	0.0028 (6)	0.0006 (5)
C12	0.0303 (6)	0.0219 (6)	0.0266 (6)	−0.0028 (5)	−0.0002 (5)	0.0019 (4)
C2	0.0358 (7)	0.0301 (6)	0.0253 (6)	−0.0048 (5)	−0.0011 (5)	0.0048 (5)

C4—C15	1.332 (2)	C14—H14B	0.960
C4—C3	1.4982 (18)	C14—H14C	0.960
C4—C5	1.5090 (16)	C6—C5	1.5067 (16)
O2—C12	1.3659 (15)	C6—H6	0.980
O2—C6	1.4708 (14)	C3—O1	1.2260 (16)
C7—C11	1.4997 (17)	C3—C2	1.473 (2)
C7—C8	1.5253 (18)	C11—C13	1.3278 (18)
C7—C6	1.5287 (16)	C11—C12	1.4991 (18)
C7—H7	0.980	C1—C2	1.334 (2)
C8—C9	1.5439 (18)	C1—C10	1.5167 (17)
C8—H8A	0.970	C1—H1	0.930
C8—H8B	0.970	C5—C10	1.5662 (15)
C9—C10	1.5437 (17)	C5—H5	0.980
C9—H9A	0.970	C15—H15A	0.930
C9—H9B	0.970	C15—H15B	0.930
O3—C12	1.2059 (16)	C13—H13A	0.930
C14—C10	1.5490 (17)	C13—H13B	0.930
C14—H14A	0.960	C2—H2	0.930
C15—C4—C3	119.26 (12)	O1—C3—C2	121.14 (13)
C15—C4—C5	125.99 (12)	O1—C3—C4	122.53 (13)
C3—C4—C5	114.71 (11)	C2—C3—C4	116.32 (11)
C12—O2—C6	107.66 (9)	C13—C11—C12	123.86 (13)
C11—C7—C8	123.60 (10)	C13—C11—C7	131.60 (13)
C11—C7—C6	99.69 (10)	C12—C11—C7	104.38 (10)
C8—C7—C6	110.63 (10)	C2—C1—C10	123.39 (12)
C11—C7—H7	107.3	C2—C1—H1	118.3
C8—C7—H7	107.3	C10—C1—H1	118.3
C6—C7—H7	107.3	C6—C5—C4	116.89 (10)
C7—C8—C9	107.08 (10)	C6—C5—C10	107.51 (9)
C7—C8—H8A	110.3	C4—C5—C10	109.63 (9)
C9—C8—H8A	110.3	C6—C5—H5	107.5
C7—C8—H8B	110.3	C4—C5—H5	107.5
C9—C8—H8B	110.3	C10—C5—H5	107.5
H8A—C8—H8B	108.6	C1—C10—C9	110.29 (10)
C10—C9—C8	113.46 (10)	C1—C10—C14	106.58 (10)
C10—C9—H9A	108.9	C9—C10—C14	110.22 (10)
C8—C9—H9A	108.9	C1—C10—C5	106.91 (10)
C10—C9—H9B	108.9	C9—C10—C5	110.69 (9)
C8—C9—H9B	108.9	C14—C10—C5	112.02 (9)
H9A—C9—H9B	107.7	C4—C15—H15A	120.0
C10—C14—H14A	109.5	C4—C15—H15B	120.0
C10—C14—H14B	109.5	H15A—C15—H15B	120.0
H14A—C14—H14B	109.5	C11—C13—H13A	120.0
C10—C14—H14C	109.5	C11—C13—H13B	120.0
H14A—C14—H14C	109.5	H13A—C13—H13B	120.0
H14B—C14—H14C	109.5	O3—C12—O2	121.23 (12)
O2—C6—C5	115.13 (9)	O3—C12—C11	129.75 (13)
O2—C6—C7	103.21 (9)	O2—C12—C11	109.00 (10)
C5—C6—C7	111.05 (10)	C1—C2—C3	121.90 (12)
O2—C6—H6	109.1	C1—C2—H2	119.1
C5—C6—H6	109.1	C3—C2—H2	119.1
C7—C6—H6	109.1
C11—C7—C8—C9	−176.53 (11)	C15—C4—C5—C10	−124.67 (13)
C6—C7—C8—C9	−58.75 (13)	C3—C4—C5—C10	52.90 (13)
C7—C8—C9—C10	55.27 (14)	C2—C1—C10—C9	151.41 (13)
C12—O2—C6—C5	153.05 (11)	C2—C1—C10—C14	−88.95 (15)
C12—O2—C6—C7	31.88 (12)	C2—C1—C10—C5	31.01 (17)
C11—C7—C6—O2	−39.39 (11)	C8—C9—C10—C1	−173.06 (11)
C8—C7—C6—O2	−171.01 (9)	C8—C9—C10—C14	69.52 (13)
C11—C7—C6—C5	−163.29 (9)	C8—C9—C10—C5	−54.96 (13)
C8—C7—C6—C5	65.10 (12)	C6—C5—C10—C1	175.55 (10)
C15—C4—C3—O1	−20.6 (2)	C4—C5—C10—C1	−56.42 (12)
C5—C4—C3—O1	161.68 (12)	C6—C5—C10—C9	55.39 (12)
C15—C4—C3—C2	158.27 (13)	C4—C5—C10—C9	−176.57 (10)
C5—C4—C3—C2	−19.48 (16)	C6—C5—C10—C14	−68.06 (12)
C8—C7—C11—C13	−19.4 (2)	C4—C5—C10—C14	59.98 (12)
C6—C7—C11—C13	−142.26 (15)	C6—O2—C12—O3	170.70 (12)
C8—C7—C11—C12	155.99 (11)	C6—O2—C12—C11	−10.45 (13)
C6—C7—C11—C12	33.14 (12)	C13—C11—C12—O3	−21.0 (2)
O2—C6—C5—C4	58.69 (14)	C7—C11—C12—O3	163.19 (14)
C7—C6—C5—C4	175.49 (10)	C13—C11—C12—O2	160.33 (12)
O2—C6—C5—C10	−177.59 (9)	C7—C11—C12—O2	−15.53 (13)
C7—C6—C5—C10	−60.79 (12)	C10—C1—C2—C3	2.2 (2)
C15—C4—C5—C6	−2.05 (18)	O1—C3—C2—C1	169.28 (13)
C3—C4—C5—C6	175.53 (10)	C4—C3—C2—C1	−9.6 (2)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O1i	0.98	2.39	3.360 (2)	171
C14—H14A···O1i	0.96	2.57	3.393 (2)	143

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯O1i	0.98	2.39	3.360 (2)	171
C14—H14A⋯O1i	0.96	2.57	3.393 (2)	143

Symmetry code: (i) .