Pterodontic acid

(1)

organic papers

Acta Cryst.(2006). E62, o1841–o1843 doi:10.1107/S1600536806012566 Meiet al. _C

15H22O2

o1841

Acta Crystallographica Section E Structure Reports Online

ISSN 1600-5368

Pterodontic acid

Zhi-Nan Mei,aYun-Fang Li,bXin Yuband Guang-Zhong Yanga*

a

Institue of National Medicine, South-Central University for Nationalities, Wuhan 430074, People’s Republic of China, andb_{College of} Pharmacy, Wuhan University, Wuhan 430072, People’s Republic of China

Correspondence e-mail: [email protected]

Key indicators

Single-crystal X-ray study T= 292 K

Mean(C–C) = 0.003 A˚ Rfactor = 0.047 wRfactor = 0.126

Data-to-parameter ratio = 11.3

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

Received 3 January 2006 Accepted 6 April 2006

#2006 International Union of Crystallography

In the title compound, C15H22O2, the C C bond lengths in

the cyclohexene ring and the allylic acid group [1.325 (3) and 1.324 (3) A˚ ] are almost equal and are shorter than those observed in ethylene. The C O and C—O bond lengths in the allylic acid group [1.201 (3) and 1.321 (3) A˚ ] are almost equal to those of formic acid. There is an intramolecular hydrogen bond between the allylic acid H atom and the hydroxy O atom [C O = 2.673 (2) A˚ and C—H O = 101_].

Comment

Laggera pterodonta (DC) Benth (Compositae) is widely distributed in southwestern China, especially in Yunnan province. It has been used as a traditional herbal medicine for its anti-inflammatory and antibacterial activities (Jiangsu New Medicial College, 1977). Previous investigations of this plant led to the isolation of 55 eudesmane sesquiterpenes and nine flavonoid compounds (Mei et al., 2005). Some eudesmane sesquiterpenes isolated from this plant showed cytotoxicity towards tumour cells (Xiao et al., 2003) and antibacterial activities (Wei et al., 1995). These interesting activities of eudesmane sesquiterpenes have prompted us to isolate more sesquiterpenes to evaluate their biological activities. As a result, one eudesmane sesquiterpene, pterodontic acid, (I) (Li et al., 1996), was isolated from an EtOAc fraction of this plant.

The molecular structure of (I) is shown in Fig. 1, the mol-ecular packing is shown in Fig. 2 and selected bond lengths are listed in Table 1. This X-ray study confirms the previously proposed molecular structure. The C C bond lengths in the cyclohexene ring and the allylic acid group are almost equal, and shorter than those observed in ethylene (1.34 A˚ ; Jerry, 1985). The C O and C—O bond lengths in the allylic acid group are almost the same as those in formic acid (1.20 and 1.34 A˚ ; Jerry, 1985). There is an intramolecular hydrogen bond between the allylic acid H atom and the hydroxy O atom (Table 2). Molecules are further linked by intermolecular hydrogen bonds between the carbonyl and hydroxy groups.

(2)

Experimental

The air-dried aerial parts of the whole plant (8 kg, dry weight) were powdered and extracted twice with 70% ethanol. The residue (845 g) obtained by removal of the solventin vacuowas suspended in water and extracted successively with petroleum ether, ethyl acetate andn -butanol. The ethyl acetate layer was evaporated to give a residue (250 g) which was subjected to column chromatography over 1500 g silica gel and eluted with a petroleum ether/ethyl acetate gradient (9:1, 8:2, 7:3, 1:1, 3:7, 0:10) and then crystallized slowly from acetone to yield compound (I) (1.2 g).1_{H NMR (300 MHz, CDCl}

3, coupling

constants in Hz in parentheses):6.31 (br s, H14a), 5.68 (br s, H14b), 5.18 (br s, H9), 1.25 (s, H7), 1.16 (d, 7.5, H1).13_{C NMR (125 MHz,}

CDCl3):23.44 (C1), 34.61 (C2), 29.94 (C3), 17.74 (C4), 42.07 (C5),

33.40 (C6), 27.45 (C7), 149.33 (C8), 126.09 (C9), 38.34 (C10), 26.83 (C11), 41.72 (C12), 145.18 (C13), 123.01 (C14), 172.76 (C15).

Crystal data

C15H22O2

Mr= 234.33

Orthorhombic,P2₁2₁2₁

a= 6.3425 (7) A˚

b= 14.0242 (15) A˚

c= 15.1156 (16) A˚

V= 1344.5 (3) A˚3

Z= 4

Dx= 1.158 Mg m

3 MoKradiation

= 0.08 mm1

T= 292 (2) K Block, colourless 0.300.200.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer

’and!scans

Absorption correction: multi-scan (SADABS; Sheldrick, 2002)

Tmin= 0.978,Tmax= 0.985

10414 measured reflections 1865 independent reflections 1676 reflections withI> 2(I)

Rint= 0.026

max= 28.0

Refinement

Refinement onF2 R[F2_{> 2}₍_F2_{)] = 0.047}

wR(F2_{) = 0.126}

S= 1.08 1865 reflections 165 parameters

H atoms treated by a mixture of independent and constrained refinement

w= 1/[2

(Fo2) + (0.0813P)2 + 0.0392P]

whereP= (Fo2+ 2Fc2)/3 (/)max< 0.001

max= 0.24 e A˚

3

min=0.18 e A˚

3

Table 1

Selected bond lengths (A˚ ).

O1—C15 1.201 (3) O2—C15 1.321 (3) C15—C13 1.490 (2) C10—C13 1.510 (3) C10—C9 1.510 (2) C10—C11 1.531 (3) C6—C8 1.521 (3) C6—C12 1.540 (3) C6—C7 1.542 (3)

[image:2.610.56.271.73.191.2]

C6—C5 1.543 (3) C9—C8 1.325 (3) C8—C2 1.530 (2) C11—C12 1.520 (3) C13—C14 1.324 (3) C2—C1 1.532 (4) C2—C3 1.538 (3) C5—C4 1.520 (3) C4—C3 1.507 (4)

Table 2

Hydrogen-bond geometry (A˚ ,_).

D—H A D—H H A D A D—H A

C14—H14A O2 0.93 2.33 2.673 (2) 101 O2—H2A O1i

0.82 (1) 1.91 (2) 2.706 (2) 162 (4)

Symmetry code: (i)xþ1 2;yþ

3 2;zþ2.

The hydroxy atom H2Aand atoms H10 and H2 were located in difference density maps and their atomic coordinates allowed to refine freely. Other H atoms were positioned geometrically and refined as riding (C—H = 0.93–0.98 A˚ ). For the CH and CH2groups,

Uiso(H) values were set equal to 1.2Ueq(C) and for the methyl groups

and the hydroxy group they were set equal to 1.5Ueq(C,O). The

absolute configuration could not be established because of the absence of significant anomalous effects. Friedel pairs were merged for the final cycles of refinement.

Data collection:SMART(Bruker, 2001); cell refinement:SAINT

(Bruker, 2001); data reduction:SAINT; program(s) used to solve structure:SHELXS97(Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics:

SHELXTL(Sheldrick, 2000); software used to prepare material for publication:SHELXTL.

We are grateful to Dr Jian-Chao Liu for the data collection.

References

Bruker. (2001).SMART(Version 5.628),SAINT(Version 6.45). Bruker AXS Inc., Madison, Wisconsin, USA.

Jerry, M. (1985).Advanced Organic Chemistry, 3rded., p. 19. New York: John Wiley and Sons.

organic papers

o1842

Meiet al. _C

15H22O2 Acta Cryst.(2006). E62, o1841–o1843

Figure 1

[image:2.610.54.291.233.427.2]

The molecular structure of the title compound, showing 50% probability displacement ellipsoids.

Figure 2

[image:2.610.314.564.429.469.2]

(3)

Jiangsu New Medical College (1977).A Dictionary of a Traditional Chinese Drugs, 1st ed., pp. 1889–1890. Shanghai: Shanghai Sciences and Technology Publishing House.

Li, S. L. & Ding, J. K. (1996).Acta Bot. Yunnan,18, 349–352.

Mei, Z. N., Li, Y. F., Yu, X. & Yang, G. Z. (2005).J. South-Central Univ. Nationalities,24, 32–35.

Sheldrick, G. M. (1990).Acta Cryst.A46, 467–473.

Sheldrick, G. M. (1997). SHELXL97. University of Go¨ttingen, Ger-many.

Sheldrick, G. M. (2000).SHELXTL. Version 6.10. Bruker AXS Inc., Madison, Wisconsin, USA.

Sheldrick, G. M. (2002).SADABS. Version 2.03. University of Go¨ttingen, Germany.

Wei, J. X., Zhao, A. H., Hu, J. L. & Zhu, Y. (1995).Acad. J. Kunming Med. College,16, 83–84.

Xiao, Y. C., Zheng, Q. X., Zhang, Q. J., Sun, H. D., Franc¸oise, G. & Zhao, Y. (2003).Fitoterapia,74, 459–463.

Xu, Y.-Q., Lv, Y.-D. & Quan, Y.-L. (2006).Acta Cryst.E62, o1844–o1845.

organic papers

Acta Cryst.(2006). E62, o1841–o1843 Meiet al. _C

(4)

supporting information

sup-1 Acta Cryst. (2006). E62, o1841–o1843

supporting information

Acta Cryst. (2006). E62, o1841–o1843 [https://doi.org/10.1107/S1600536806012566]

Pterodontic acid

Zhi-Nan Mei, Yun-Fang Li, Xin Yu and Guang-Zhong Yang

Pterodontic acid

Crystal data

C15H22O2

Mr = 234.33

Orthorhombic, P212121 Hall symbol: P ac ab

a = 6.3425 (7) Å

b = 14.0242 (15) Å

c = 15.1156 (16) Å

V = 1344.5 (3) Å3

Z = 4

F(000) = 512

Dx = 1.158 Mg m−3

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 4272 reflections

θ = 2.7–26.6°

µ = 0.08 mm−1

T = 292 K Block, colorless 0.30 × 0.20 × 0.20 mm

Data collection

Bruekr SMART CCD area-detector diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

Detector resolution: 10 pixels mm-1

φ and ω scans

Absorption correction: multi-scan (SADABS; Sheldrick, 2002)

Tmin = 0.978, Tmax = 0.985

10414 measured reflections 1865 independent reflections 1676 reflections with I > 2σ(I)

Rint = 0.026

θmax = 28.0°, θmin = 2.0°

h = −8→8

k = −18→16

l = −19→19

Refinement

Refinement on F2 Least-squares matrix: full

R[F2_{> 2}_σ₍_F2_{)] = 0.047}

wR(F2_{) = 0.126}

S = 1.08 1865 reflections 165 parameters 1 restraint

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H atoms treated by a mixture of independent and constrained refinement

w = 1/[σ2₍_F

o2) + (0.0813P)2 + 0.0392P] where P = (Fo2 + 2Fc2)/3

(Δ/σ)max < 0.001 Δρmax = 0.24 e Å−3 Δρmin = −0.18 e Å−3

Special details

(5)

supporting information

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.}

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2₎

x y z Uiso*/Ueq

O1 0.2674 (3) 0.77996 (13) 0.94391 (9) 0.0639 (5)

O2 0.5976 (3) 0.76509 (15) 0.89728 (9) 0.0671 (5)

C15 0.3940 (3) 0.77953 (13) 0.88478 (12) 0.0429 (4)

C10 0.1200 (3) 0.83565 (14) 0.77384 (11) 0.0408 (4)

H10 0.020 (4) 0.8000 (17) 0.8104 (14) 0.049*

C6 −0.0907 (3) 0.99114 (13) 0.66582 (12) 0.0417 (4)

C9 0.0512 (3) 0.82603 (13) 0.67860 (12) 0.0419 (4)

H9 0.0730 0.7671 0.6520 0.050*

C8 −0.0371 (3) 0.89307 (13) 0.62917 (11) 0.0385 (4)

C11 0.1111 (4) 0.94016 (15) 0.80279 (12) 0.0501 (5)

H11A 0.1128 0.9438 0.8669 0.060*

H11B 0.2340 0.9737 0.7806 0.060*

C13 0.3367 (3) 0.79472 (13) 0.79024 (11) 0.0395 (4)

C2 −0.0944 (4) 0.87123 (16) 0.53294 (12) 0.0485 (5)

H2 −0.097 (4) 0.802 (2) 0.5270 (15) 0.058*

C5 −0.3155 (4) 1.01941 (17) 0.63687 (14) 0.0543 (5)

H5A −0.4164 0.9800 0.6683 0.065*

H5B −0.3410 1.0852 0.6536 0.065*

C4 −0.3520 (4) 1.00876 (18) 0.53798 (15) 0.0604 (6)

H4A −0.4950 1.0278 0.5236 0.072*

H4B −0.2560 1.0502 0.5060 0.072*

C14 0.4752 (4) 0.77196 (17) 0.72817 (12) 0.0561 (6)

H14A 0.6057 0.7470 0.7439 0.067*

H14B 0.4419 0.7810 0.6688 0.067*

C12 −0.0879 (4) 0.98722 (16) 0.76764 (13) 0.0526 (5)

H12A −0.0976 1.0515 0.7910 0.063*

H12B −0.2100 0.9519 0.7882 0.063*

C3 −0.3170 (4) 0.90683 (18) 0.50996 (14) 0.0570 (6)

H3A −0.3386 0.9016 0.4466 0.068*

H3B −0.4202 0.8664 0.5389 0.068*

C7 0.0681 (4) 1.06739 (15) 0.63492 (16) 0.0570 (6)

H7A 0.2087 1.0468 0.6486 0.085*

H7B 0.0396 1.1265 0.6647 0.085*

H7C 0.0549 1.0764 0.5722 0.085*

C1 0.0698 (5) 0.9083 (2) 0.46701 (14) 0.0691 (7)

H1A 0.0677 0.9768 0.4667 0.104*

H1B 0.0372 0.8851 0.4089 0.104*

H1C 0.2073 0.8864 0.4841 0.104*

(6)

supporting information

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

O1 0.0695 (11) 0.0883 (12) 0.0340 (6) −0.0019 (9) 0.0052 (7) 0.0140 (7)

O2 0.0609 (10) 0.0990 (13) 0.0416 (7) 0.0134 (10) −0.0121 (7) 0.0128 (8)

C15 0.0520 (11) 0.0431 (10) 0.0338 (8) −0.0016 (9) −0.0041 (8) 0.0059 (7)

C10 0.0444 (10) 0.0447 (9) 0.0332 (8) −0.0019 (8) −0.0015 (8) 0.0054 (7)

C6 0.0430 (10) 0.0395 (9) 0.0425 (9) 0.0010 (8) −0.0016 (8) 0.0014 (7)

C9 0.0512 (11) 0.0359 (8) 0.0384 (8) 0.0003 (8) −0.0072 (8) −0.0038 (7)

C8 0.0395 (9) 0.0422 (9) 0.0340 (8) −0.0030 (8) −0.0037 (7) −0.0002 (7)

C11 0.0585 (13) 0.0538 (11) 0.0381 (9) 0.0042 (10) −0.0078 (9) −0.0098 (8)

C13 0.0472 (10) 0.0385 (8) 0.0330 (8) −0.0047 (8) −0.0010 (7) 0.0065 (7)

C2 0.0579 (12) 0.0507 (11) 0.0369 (9) −0.0035 (10) −0.0109 (9) −0.0015 (8)

C5 0.0502 (12) 0.0556 (12) 0.0573 (12) 0.0095 (10) −0.0013 (10) 0.0070 (10) C4 0.0484 (13) 0.0757 (15) 0.0571 (12) 0.0052 (11) −0.0108 (10) 0.0169 (11)

C14 0.0576 (13) 0.0756 (15) 0.0353 (9) 0.0066 (12) 0.0018 (9) 0.0074 (9)

C12 0.0596 (13) 0.0564 (11) 0.0417 (9) 0.0142 (11) 0.0010 (9) −0.0108 (8)

C3 0.0558 (13) 0.0737 (14) 0.0416 (10) −0.0130 (12) −0.0144 (10) 0.0079 (10) C7 0.0574 (14) 0.0452 (11) 0.0683 (13) −0.0081 (10) −0.0012 (12) −0.0005 (10)

C1 0.0659 (16) 0.1010 (19) 0.0405 (10) 0.0000 (15) 0.0023 (11) −0.0053 (12)

Geometric parameters (Å, º)

O1—C15 1.201 (3) C2—C3 1.538 (3)

O2—C15 1.321 (3) C2—H2 0.98 (3)

O2—H2A 0.820 (10) C5—C4 1.520 (3)

C15—C13 1.490 (2) C5—H5A 0.9700

C10—C13 1.510 (3) C5—H5B 0.9700

C10—C9 1.510 (2) C4—C3 1.507 (4)

C10—C11 1.531 (3) C4—H4A 0.9700

C10—H10 0.98 (2) C4—H4B 0.9700

C6—C8 1.521 (3) C14—H14A 0.9300

C6—C12 1.540 (3) C14—H14B 0.9300

C6—C7 1.542 (3) C12—H12A 0.9700

C6—C5 1.543 (3) C12—H12B 0.9700

C9—C8 1.325 (3) C3—H3A 0.9700

C9—H9 0.9300 C3—H3B 0.9700

C8—C2 1.530 (2) C7—H7A 0.9600

C11—C12 1.520 (3) C7—H7B 0.9600

C11—H11A 0.9700 C7—H7C 0.9600

C11—H11B 0.9700 C1—H1A 0.9600

C13—C14 1.324 (3) C1—H1B 0.9600

C2—C1 1.532 (4) C1—H1C 0.9600

C15—O2—H2A 111 (3) C4—C5—H5A 108.9

O1—C15—O2 123.21 (18) C6—C5—H5A 108.9

O1—C15—C13 123.4 (2) C4—C5—H5B 108.9

(7)

supporting information

C13—C10—C9 112.69 (16) H5A—C5—H5B 107.7

C13—C10—C11 110.53 (17) C3—C4—C5 110.32 (18)

C9—C10—C11 110.32 (15) C3—C4—H4A 109.6

C13—C10—H10 107.7 (14) C5—C4—H4A 109.6

C9—C10—H10 107.7 (13) C3—C4—H4B 109.6

C11—C10—H10 107.7 (13) C5—C4—H4B 109.6

C8—C6—C12 109.20 (15) H4A—C4—H4B 108.1

C8—C6—C7 111.75 (17) C13—C14—H14A 120.0

C12—C6—C7 108.65 (18) C13—C14—H14B 120.0

C8—C6—C5 109.62 (17) H14A—C14—H14B 120.0

C12—C6—C5 107.66 (17) C11—C12—C6 111.99 (17)

C7—C6—C5 109.86 (17) C11—C12—H12A 109.2

C8—C9—C10 126.61 (17) C6—C12—H12A 109.2

C8—C9—H9 116.7 C11—C12—H12B 109.2

C10—C9—H9 116.7 C6—C12—H12B 109.2

C9—C8—C6 122.05 (15) H12A—C12—H12B 107.9

C9—C8—C2 119.63 (17) C4—C3—C2 112.3 (2)

C6—C8—C2 118.29 (16) C4—C3—H3A 109.1

C12—C11—C10 110.27 (18) C2—C3—H3A 109.1

C12—C11—H11A 109.6 C4—C3—H3B 109.1

C10—C11—H11A 109.6 C2—C3—H3B 109.1

C12—C11—H11B 109.6 H3A—C3—H3B 107.9

C10—C11—H11B 109.6 C6—C7—H7A 109.5

H11A—C11—H11B 108.1 C6—C7—H7B 109.5

C14—C13—C15 118.89 (19) H7A—C7—H7B 109.5

C14—C13—C10 125.39 (17) C6—C7—H7C 109.5

C15—C13—C10 115.73 (16) H7A—C7—H7C 109.5

C8—C2—C1 112.89 (19) H7B—C7—H7C 109.5

C8—C2—C3 111.58 (18) C2—C1—H1A 109.5

C1—C2—C3 111.52 (18) C2—C1—H1B 109.5

C8—C2—H2 106.8 (14) H1A—C1—H1B 109.5

C1—C2—H2 106.8 (15) C2—C1—H1C 109.5

C3—C2—H2 106.8 (16) H1A—C1—H1C 109.5

C4—C5—C6 113.22 (19) H1B—C1—H1C 109.5

C13—C10—C9—C8 −134.3 (2) C9—C10—C13—C15 −165.47 (17)

C11—C10—C9—C8 −10.2 (3) C11—C10—C13—C15 70.6 (2)

C10—C9—C8—C6 −2.9 (3) C9—C8—C2—C1 −99.2 (3)

C10—C9—C8—C2 179.2 (2) C6—C8—C2—C1 82.7 (3)

C12—C6—C8—C9 −16.3 (3) C9—C8—C2—C3 134.3 (2)

C7—C6—C8—C9 104.0 (2) C6—C8—C2—C3 −43.8 (2)

C5—C6—C8—C9 −134.0 (2) C8—C6—C5—C4 −51.0 (2)

C12—C6—C8—C2 161.73 (18) C12—C6—C5—C4 −169.64 (19)

C7—C6—C8—C2 −78.0 (2) C7—C6—C5—C4 72.2 (3)

C5—C6—C8—C2 44.0 (2) C6—C5—C4—C3 59.5 (3)

C13—C10—C11—C12 167.21 (16) C10—C11—C12—C6 −64.0 (2)

C9—C10—C11—C12 41.9 (2) C8—C6—C12—C11 49.0 (2)

(8)

supporting information

O2—C15—C13—C14 14.9 (3) C5—C6—C12—C11 167.97 (19)

O1—C15—C13—C10 15.1 (3) C5—C4—C3—C2 −57.8 (3)

O2—C15—C13—C10 −165.19 (18) C8—C2—C3—C4 49.2 (2)

C9—C10—C13—C14 14.5 (3) C1—C2—C3—C4 −78.0 (2)

C11—C10—C13—C14 −109.5 (2)

Hydrogen-bond geometry (Å, º)

D—H···A D—H H···A D···A D—H···A

C14—H14A···O2 0.93 2.33 2.673 (2) 101

O2—H2A···O1i _{0.82 (1)} _{1.91 (2)} _{2.706 (2)} _{162 (4)}