Two new sesquiterpene glucosides from Gymnaster koraiensis

Article abstract of DOI:10.3987/COM-09-11773

Two new sesquiterpene glucosides, 1(R),4β-dihydroxy-trans-eudesm-6-ene-1-O-β-D-glucopyranoside (1) and 1(R),4β-dihydroxy-trans-eudesm-7-ene-1-O-β-D-glucopyranoside (2), together with six other known compounds, were isolated from the flowers of Gymnaster k

Full text of DOI:10.3987/COM-09-11773

HETEROCYCLES, Vol. 78, No. 11, 2009
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HETEROCYCLES, Vol. 78, No.11, 2009, pp. 2827 - 2835. © The Japan Institute of Heterocyclic Chemistry
Received, 9th June, 2009, Accepted, 30th July, 2009, Published online, 31st July, 2009
DOI: 10.3987/COM-09-11773
TWO NEW SESQUITERPENE GLUCOSIDES FROM GYMNASTER
KORAIENSIS
Il Kyun Lee,a Ki Hyun Kim,a Shi Yong Ryu,b and Kang Ro Leea,*
aNatural Products Laboratory, College of Pharmacy, Sungkyunkwan University,
b
Suwon 440-746, Korea. Korea Research Institute of Chemical Technology,
Taejeon 305-600, Korea
*e-mail address: krlee@skku.ac.kr
Abstract – Two new sesquiterpene glucosides, 1(R),4β-dihydroxy-trans-eudesm-
6-ene-1-O-β-D-glucopyranoside (1) and 1(R),4β-dihydroxy-trans-eudesm-7-ene-
1-O-β-D-glucopyranoside (2), together with six other known compounds, were
isolated from the flowers of Gymnaster koraiensis (Nakai) Kitamura
(Compositae). The identification and structural elucidation of these compounds
were based on 1D- and 2D-NMR spectral data analysis. The absolute
configurations of 1 and 2 were determined by a convenient Mosher ester
procedure carried out in NMR tube.
INTRODUCTION
Gymnaster koraiensis (Nakai) Kitamura (Compositae) is widely distributed in the north of Korea. This
indigenous herb is used as a folk medicine for antitussive and antibacterial activities.1 Previous
phytochemical studies on this plant showed the presence of polyacetylenes, polyacetylene glucosides and
benzofurans.2-5 Column chromatographic purification of the BuOH-soluble fraction of the EtOH extract
of the flowers of this source led to the isolation of two new sesquiterpene glucosides (1-2), together with
six other known compounds (3-8). The structures of the known compounds were determined to be
oplopanone-8-O-β-D-glucopyranoside (3),6,7 3(R)-8(E)-decene-4,6-diyne-1,3-diol-1-O-β-D-glucopyrano
side (4),4,8 8(E)-decene-4,6-diyne-1-O-β-D-glucopyranoside (5),4 8(E)-decene-4,6-diyne-1-O-β-D-
apinofuranosyl-(1→6)-β-D-glucopyranoside (6),8 eugenyl-O-β-D-glucopyranoside (7)9 and
2-phenylethyl-O-β-D-glucopyranoside (8)10 by comparing their spectroscopic data with those in published
literature. The known compounds (3, 5-8) were reported from this source for the first time.

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HETEROCYCLES, Vol. 78, No. 11, 2009
Figure 1. The structures of the isolated compounds (1–8) from G. koraiensis
RESULTS AND DISCUSSION
Compound 1 was obtained as a colorless gum, whose molecular formula was determined to be C21H36O7
from the [M + Na]+ peak at m/z 423.2362 (calcd. for C21H36O7Na: 423.2359) in the positive-ion
HR-FABMS. The IR spectrum indicated that 1 possessed hydroxyl (3416 cm-1) and C=C double bond
13
(1650 cm-1) functional groups. In the C-NMR (including DEPT) spectra, 21 carbon signals appeared,
which included four methyl carbons at C = 29.6, 22.2, 21.9 and 13.0, four methylene carbons at C =
40.2, 36.5, 24.2 and 23.9, two methine carbons at C = 51.9 and 36.7, one oxygenated methine carbon at
C = 85.8, two olefinic carbons C = 145.3 and 118.2, one oxygenated quaternary carbon at C = 71.7 and,
one quaternary carbon at C = 38.9, including six signals assignable to the glucose moiety (C = 102.2,
78.4, 77.9, 75.3, 72.1, 63.2), were observed. The NMR data were very similar except for the glucose part
to those of 1β,4β-dihydroxy-trans-eudesm-6-ene, which was isolated from Pulicaria paludosa.11 The only
difference was the chemical shift at C-1 (H = 3.44, dd, J = 12.0, 4.5 Hz; C = 85.8 in 1; H = 3.35, dd,
J = 11.6, 4.0 Hz; C = 80.0 in 1β,4β-dihydroxy-trans-eudesm-6-ene). The downfield shift at C-1 implied
that 1 was glycosylated at C-1.12 The sugar moiety appeared at H = 4.33 (d, J = 7.5 Hz), 3.85 (dd, J =
11.5, 2.5 Hz), 3.67 (dd, J = 11.5, 5.5 Hz), 3.36 (m), 3.30 (m), 3.24 (m), 3.16 (dd, J = 9.1, 7.5 Hz) in the
13
1H-NMR spectrum and at C = 102.2, 78.4, 77.9, 75.3, 72.1, 63.2 in the C-NMR spectrum, suggesting
the presence of D-glucose moiety. The coupling constant (J = 7.5 Hz) of the anomeric proton of D-glucose

HETEROCYCLES, Vol. 78, No. 11, 2009
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moiety indicated it to be the β-form.13 The position of D-glucose moiety was reconfirmed by an HMBC
experiment, in which long-range correlation was observed between the H-1 (δH = 4.33, d, J = 7.5 Hz)
and C-1 (δC = 85.8) (Figure 2). Thus, the structure of 1 was supposed to be 1β,4β-dihydroxy-trans-
eudesm-6-ene-1-O-β-D-glucopyranoside. The relative stereochemistry was confirmed by NOESY
spectrum. The correlations of H-5 with H-1 and H-14 (not with C-15) were observed in the NOESY
experiment (Figure 2). In addition, enzymatic hydrolysis of 1 with β-glucosidase (emulsin) yielded
1
1β,4β-dihydroxy-trans-eudesm-6-ene (1a, C15H26O2, [α]25 : - 12.0°), whose H-NMR and MS spectra
D
were in good agreement with values reported previously,11,14 and D-glucose ([α]25 : + 50.4 ° (c 0.05, H2O).
D
Determination of the absolute configuration at C-1 of 1 was examined with the convenient Mosher’s
method.15 Compound 1a, obtained by enzyme hydrolysis of 1, was treated with (S)-(+)- and
(R)-(-)-α-methoxy-α-trifluromethylphenylacetic acid (MTPA) chlorides to give (R)- and (S)-MTPA esters
(1b and 1c, respectively). As shown in Figure 4, the H-2, 3 and 14 of the (S)-MTPA ester (1c) resonated at
lower field than those of the (R)-MTPA ester (1b), while the H-8, 9 and 15 of 1s were observed at higher
field compared to those of 1b. Consequently, the absolute configuration at C-1 in 1 was to be R-form.
Thus, the structure of 1 was determined to be 1(R),4β-dihydroxy-trans-eudesm-6-ene-1-O-β-
D-glucopyranoside.
Figure 2. Key HMBC (
) (a) and NOESY (
) (b) correlations of 1
Compound 2 was obtained as a colorless gum, whose molecular formula was determined to be C21H36O7
from the [M + Na]+ peak at m/z 423.2358 (calcd. for C21H36O7Na: 423.2359) in the positive-ion
HR-FABMS. The IR spectrum indicated that 2 possessed a hydroxyl group at 3386 cm-1 and a C=C
double bond at 1649 cm-1. The NMR spectra of 2 were very similar to those of compound 1. In the
13C-NMR spectrum of 2, two olefinic carbon signals observed at δC= 145.3 and 118.2 in 1 were slightly
shifted upfield to δC = 142.9 and 118.0 in 2, respectively. Furthermore, the coupling pattern of an olefinic
1
proton in the H-NMR spectrum was different (H = 5.54, br. s in 1; H = 5.53, br. d, J = 5.7 Hz in 2).16
These observations suggested that the structure of 2 was 1β,4β-dihydroxy-trans-eudesm-7-ene-

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1
1-O-β-D-glucopyranoside. Analysis of the H-1H COSY, HMQC and HMBC spectra permitted the
assignment of all proton and carbon signals for 2 the location of the double bond, and the glycosyl
linkage (Figure 3). Enzymatic hydrolysis of 2 with β-glucosidase (Emulsin) of 2 yielded
1
1β,4β-dihydroxy-trans-eudesm-7-ene (2a, C15H26O2, [α]25 : - 35.0°), whose H-NMR and MS spectra
D
were in good agreement with values reported previously,11,17 and D-glucose ([α]25 : + 53.2 ° (c 0.05, H2O).
D
The relative stereochemistry was confirmed by NOESY spectrum (Figure 3). Determination of the
absolute configuration at C-1 of 2 was examined with the convenient Mosher’s method.15 Compound 2a,
obtained by enzyme hydrolysis of 2, was treated with (S)-(+)- and (R)-(-)-α-methoxy-
α-trifluromethylphenylacetic acid (MTPA) chlorides to give (R)- and (S)-MTPA esters (2b and 2c,
respectively). As shown in Figure 4, the H-2, 3 and 14 of the (S)-MTPA ester (2c) resonated at lower field
than those of the (R)-MTPA ester (2b), while the H-8, 9 and 15 of 1s were observed at higher field
compared to those of 2b. Consequently, the absolute configuration at C-1 in 2 was to be R. Therefore, the
structure of 2 was determined to be 1(R),4β-dihydroxy-trans-eudesm-7-ene-1-O-β-D-glucopyranoside.
Figure 3. Key HMBC (
) (a) and NOESY (
) (b) correlations of 2
Figure 4. Values of δS-δR (data obtained in pyridine-d5) of the MTPA esters of 1a and 2a.

HETEROCYCLES, Vol. 78, No. 11, 2009
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EXPERIMENTAL DETAILS
General. Optical rotations were measured on a Jasco P-1020 polarimeter in MeOH and H2O. IR spectra
were recorded on a Bruker IFS-66/S FT-IR spectrometer. FAB and HR-FAB mass spectra were obtained
on a JEOL JMS700 mass spectrometer. NMR spectra, including NOESY, DEPT and HMBC experiments,
were recorded on a Varian UNITY INOVA 500 NMR spectrometer operating at 500 MHz (1H) and 125
MHz (13C), respectively, with chemical shifts given in ppm (δ) using TMS as an internal standard.
Preparative HPLC was conducted using a Gilson 306 pump with Shodex refractive index detector. Silica
gel 60 (Merck, 70-230 mesh and 230-400 mesh) and RP-C18 silica gel (Merck, 230-400 mesh) were used
for column chromatography. Merck precoated Silica gel F254 plates and RP-18 F254s plates were used for
TLC. Spots were detected on TLC under UV light or by heating after spraying with 10% H2SO4 in
C2H5OH (v/v). The packing material for molecular sieve column chromatography was Sephadex LH-20
(Pharmacia Co.). Low pressure liquid chromatography was carried out over a Merck Lichroprep
Lobar®-A Si 60 (240×10 mm) or a Lichroprep Lobar®-A RP-18 (240×10 mm) column with a FMI QSY-0
pump (ISCO).
Plant material. The flower parts of Gymnaster koraiensis (Nakai) Kitamura (Compositae) (5 kg) were
collected at Pyeongchang in Gangwon province, Korea in August 2006 and identified by Prof. Kang Ro
Lee. A voucher specimen of the plant (SKK-07-006) was deposited at the College of Pharmacy in
Sungkyunkwan University.
Extraction and isolation. The half dried flower parts of G. koraiensis (5 kg) were extracted with EtOH
three times at room temperature. The resultant EtOH extracts (250 g) were suspended in distilled water
(800 mL Χ 3) and then successively partitioned with n-hexane, CHCl3, EtOAc and n-BuOH, yielding 27
g, 7 g and 85 g, respectively. The n-BuOH soluble fraction (85 g) was chromatographed on a Diaion
HP-20, eluting with a gradient solvent system of water and MeOH to give two subfractions. Fraction B
(48 g) silica gel (230-400 mesh, 350 g), was eluted with a gradient solvent system of MeOH/H2O (1:1,
3.5:1 and 1:0). According to TLC analysis, nine crude fractions (fr. BA-BI) were collected. Fr. BB (6.8 g)
was further chromatographed on a CHCl3/MeOH/Water (35:10:1–10:5:1) to give nine fractions (BB1 –
BB9). Fr. BB2 was eluted with a gradient solvent system of CHCl3/MeOH/Water (35:10:1) to give four
subfractions (fr. BB21 – BB24). Fr. BB23 (540 mg) was column chromatography on a RP-C18 silica gel
(230-400 mesh, 100 g), using a solvent system of 50% MeOH, and purified by preparative normal-phase
HPLC with a solvent system of CHCl3/MeOH (6:1) to yield 1 (4 mg) and 2 (25 mg). Fr. BB22 (140 mg)
was purified by Lobar®-A RP-18 (240×10 mm) column (25% MeOH), and further purified by preparative
normal-phase HPLC, using a solvent system of CHCl3/MeOH (7:1) to yield 3 (19 mg). Fr. BA (2.7 g)
silica gel (230-400 mesh 100 g) was eluted with a solvent system of MeOH/H2O (13:1). According to

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TLC analysis, seven fractions (fr. BA1-BA7) were collected. Fr. BA6 (220 mg) was further purified by
preparative reversed-phase HPLC, using a solvent system of 55% MeOH to yield 7 (15 mg). Fr. BA7
(200 mg) was further purified by preparative normal-phase HPLC, using a solvent system of
CHCl3/MeOH (7:1) to yield 4 (15 mg) and 8 (43 mg). Fr. BB24 (420 mg) was purified by Lobar®-A
RP-18 (240×10 mm) column (55% MeOH), and further purified by preparative normal-phase HPLC,
using a solvent system of CHCl3/MeOH (4:1) to yield 5 (138 mg). Fr. BB27 (1.5 g) was resolved by
column chromatography on a silica gel (230-400 mesh, 100 g), eluting with a gradient solvent system of
CHCl3/MeOH (6:1 and 4:1) to give three fractions (fr. BB271 – BB273). Fr. BB273 (200 mg) was
purified by preparative normal-phase HPLC, using a solvent system of CHCl3/MeOH (4:1) to yield 6 (11
mg).
1(R),4β-Dihydroxy-trans-eudesm-6-ene-1-O-β-D-glucopyranoside (1). Colorless gum. [α]2D5 - 51.5° (c
0.05, MeOH); IR (KBr) νmax cm-1: 3416, 2961, 1650, 1057, 1004; FABMS m/z (rel. int.) = 423 ([M +
Na]+); HR-FABMS m/z = 423.2362 [M + Na]+ (calcd for C21H36O7Na:423.2359); 1H- NMR: see Table 1.;
13C-NMR (CD3OD, 125 MHz): δ 145.3 (C-7), 118.2 (C-6), 102.2 (C-1), 85.8 (C-1), 78.4 (C-3), 77.9
(C-5), 75.3 (C-2), 72.1 (C-4), 71.7 (C-4), 63.2 (C-6), 51.9 (C-5), 40.2 (C-3), 38.9 (C-10), 36.7 (C-11),
36.5 (C-9), 29.6 (C-14), 24.2 (C-2), 23.9 (C-8), 22.2 (C-13), 21.9 (C-12), 13.0 (C-15).
1(R),4β-Dihydroxy-trans-eudesm-7-ene-1-O-β-D-glucopyranoside (2). Colorless gum. [α]2D5 - 43.7 ° (c
0.2, MeOH); IR (KBr) νmax cm-1: 3386, 2960, 1649, 1372, 1076, 1024; FABMS m/z (rel. int.) = 423 ([M +
Na]+); HR-FABMS m/z = 423.2358 [M + Na]+ (calcd. for C21H36O7Na:423.2359); 1H- NMR: see Table 1.;
13C-NMR (CD3OD, 125 MHz): δ 142.9 (C-7), 118.0 (C-8), 101.9 (C-1), 86.9 (C-1), 79.6 (C-3), 77.9
(C-5), 75.3 (C-2), 72.1 (C-4), 71.6 (C-4), 63.2 (C-6), 48.5 (C-5), 42.0 (C-9), 40.3 (C-3), 38.4 (C-10),
36.5 (C-11), 30.0 (C-14), 24.3 (C-6), 23.9 (C-2), 22.4 (C-13), 21.8 (C-12), 13.2 (C-15).
Enzymatic hydrolysis of 1 and 2 using β-glucosidase. Compound 1 (2.0 mg) with 2 mL of H2O and 4
mg of β-glucosidase18,19 (Emulsin) was shaken for 7 days at 36 °C. The H2O solution was then extracted
with EtOAc three times, and the EtOAc extract was evaporated in vacuo. The EtOAc extract (2.0 mg)
was purified using Silica HPLC (CHCl3:MeOH = 9:1) to afford aglycone 1a (1.5 mg) as a colorless gum
1
[α]25 - 12.0 ° (c 0.05, CHCl3), H-NMR (CDCl3, 500 MHz): see Table 1. Compound 2 (3.0 mg) was
D
treated by the same method. The EtOAc extract (2.0 mg) was purified using silica HPLC (CHCl3:MeOH
= 9:1) to afford aglycone 2a (1.5 mg) as a colorless gum [α]25 - 35.0 ° (c 0.1, CHCl3), 1H-NMR (CDCl3,
D
500 MHz): see Table 1. The sugar in the water layer was identified as D-glucose by co-TLC
(EtOAc:MeOH:H2O = 9:3:1, Rf value : 0.2, 1a : 0.5 mg, 2a : 0.5 mg) with a D-glucose standard (Aldrich
Co., USA).

HETEROCYCLES, Vol. 78, No. 11, 2009
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Preparation of the (R)- and (S)-MTPA Ester Derivatives of 1a and 2a by a Convenient Mosher
Ester.15 Compounds 1a (0.7 mg) and 2a (0.7 mg) in deuterated pyrindine-d5 (1.0 mL) was transferred into
clean NMR tube. (S)-(+)-α-methoxy-α-trifluromethylphenylacetic acid (MTPA) chlorides (10 µL) was
added into the NMR tube immediately under a N2 gas stream, and then the NMR tube was permitted to
stand at room temperature. After overnight, the reaction was completed to afford the (R)-MTPA ester
derivatives (1b and 2b) of 1a and 2a, respectively. In manner described for 1b and 2b, (S)-MTPA ester
1
derivatives (1c and 2c) of 1a and 2a were obtained. The H-NMR spectra of 1b, 2b, 1c and 2c were
measured with the reaction NMR tubes directly.
1b. (500 MHz, pyridine-d5): δ 5.719 (1H, br s, H-6), 5.040 (1H, dd, J = 11.5, 4.0 Hz, H-1), 2.135 (1H, q,
J = 7.0 Hz, H-11), 2.064 (1H, m, H-9a), 2.045 (1H, m, H-8a), 2.025 (1H, m, H-8b), 1.998 (1H, m, H-2a),
1.830 (1H, m, H-5), 1.690 (1H, m, H-3a), 1.638 (1H, m, H-2b), 1.529 (1H, m, H-3b), 1.485 (1H, m,
H-9b), 1.373 (3H, s, H-14), 1.340 (3H, s, H-15), 1.914 (3H, d, J = 7.0 Hz, H-12), 0.908 (3H, d, J = 7.0 Hz,
H-13).
1c. (500 MHz, pyridine-d5): δ 5.709 (1H, br s, H-6), 5.040 (1H, dd, J = 11.5, 4.0 Hz, H-1), 2.133 (1H, q, J
= 7.0 Hz, H-11), 2.110 (1H, m, H-9a), 2.044 (1H, m, H-8a), 2.012 (1H, m, H-8b), 2.010 (1H, m, H-2a),
1.800 (1H, m, H-5), 1.714 (1H, m, H-3a), 1.642 (1H, m, H-2b), 1.536 (1H, m, H-3b), 1.457 (1H, m,
H-9b), 1.376 (3H, s, H-14), 1.310 (3H, s, H-15), 0.907 (3H, s, J = 7.0 Hz, H-12), 0.888 (3H, d, J = 7.0 Hz,
H-13).
2b. (500 MHz, pyridine-d5): δ 5.289 (1H, br s, H-8), 4.999 (1H, dd, J = 12.5, 3.5 Hz, H-1), 2.496 (1H, m,
9a), 2.496 (1H, m, H-6a), 2.268 (1H, qd, J = 13.5, 3.5, H-2a), 2.144 (1H, q, J = 7.0 Hz, H-11), 2.098 (1H,
m, H-6b), 2.053 (1H, m, H-9b), 1.893 (1H, dt, J = 13.5, 3.5 Hz, H-3a), 1.846 (1H, dq, J = 13.5, 3.5 Hz,
H-2b), 1.567 (1H, td, J = 13.5, 3.5 Hz, H-3b), 1.375 (1H, dd, J = 12.3, 4.5 Hz, H-5), 1.341 (3H, s, H-14),
1.279 (3H, s, H-15), 0.959 (3H, d, J = 7.0 Hz, H-12), 0.956 (3H, d, J = 7.0 Hz, H-13).
2c. (500 MHz, pyridine-d5): δ 5.272 (1H, br s, H-8), 4.999 (1H, dd, J = 12.5, 3.5 Hz, H-1), 2.467 (1H, m,
9a), 2.472 (1H, m, H-6a), 2.277 (1H, qd, J = 13.5, 3.5, H-2a), 2.132 (1H, q, J = 7.0 Hz, H-11), 2.077 (1H,
m, H-6b), 2.040 (1H, m, H-9b), 1.905 (1H, dt, J = 13.5, 3.5 Hz, H-3a), 1.866 (1H, dq, J = 13.5, 3.5 Hz,
H-2b), 1.589 (1H, td, J = 13.5, 3.5 Hz, H-3b), 1.360 (1H, dd, J = 12.3, 4.5 Hz, H-5), 1.352 (3H, s, H-14),
1.247 (3H, s, H-15), 0.939 (3H, d, J = 7.0 Hz, H-12), 0.932 (3H, d, J = 7.0 Hz, H-13).

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HETEROCYCLES, Vol. 78, No. 11, 2009
Table 1. 1H-NMR chemical shifts of 1, 1a, 2 and 2a
1
1a
2
2a
Position
a)
b)
a)
b)
δH
3.44 (dd, 12.0, 4.5)
2.07 mc)
δH
δH
δH
1
2
3.34 (dd, 12.0, 4.5)
1.94 mc)
3.43 (dd, 12.0, 3.5)
1.89 mc)
3.32 (dd, 11.7, 4.0)
1.89 mc)
1.74 mc)
1.74 mc)
1.80 (dq, 12.0, 4.5)
1.77 (dt, 12.0, 4.0)
1.52 (td, 12.0, 4.0)
1.71 (dq, 12.0, 3.5)
1.78 (dt, 12.0, 3.5)
1.49 (td, 12.0, 3.5)
1.61 (dq, 13.0, 4.0)
1.76 (dt, 14.0, 4.0)
1.56 (td, 14.0, 4.0)
3
1.50 ( td, 12.0, 4.5)
4
5
6
1.84 br s
5.54 br s
1.86 br s
5.47 br s
1.30 (dd, 12.5, 5.2)
2.17 mc)
1.92 mc)
1.33(dd, 12.3, 5.2)
2.08 mc)
2.05 mc)
7
8
2.03 mc)
2.03 mc)
2.03 mc)
1.26 mc)
2.06 mc)
1.94 mc)
2.10 mc
1.28 mc)
5.32 (br d, 5.7)
5.35 (br d, 5.8)
9
2.13 mc)
1.92 mc)
2.05 mc)
1.92 mc)
10
11
2.25 (q, 7.0)
1.05 (d, 7.0)
1.05 (d, 7.0)
1.21 s
2.27 (q, 6.5)
1.04 (d, 6.5)
1.04 (d, 6.5)
1.25 s
2.21 (q, 7.0)
1.03 (d, 7.0)
1.05 (d, 7.0)
1.16 s
2.22 (q, 7.0)
1.03 (d, 7.0)
1.04 (d, 7.0)
1.20 s
12
13
14
15
1
2
3
4
5
6a
6b
1.01 s
0.99 s
1.01 s
0.98 s
4.33 (d, 7.5)
3.16 (dd, 9.1, 7.5)
3.24 mc)
3.30 mc)
3.36 mc)
4.33 (d, 8.0)
3.18 (dd, 9.1, 8.0)
3.24 mc)
3.30 mc)
3.36 mc)
3.67 (dd, 11.5, 5.5)
3.85 (dd, 11.5, 2.5)
3.68 (dd, 11.5, 5.7)
3.87 (dd, 11.5, 2.3)
a) 500 MHz, CD3OD; chemical shifts in ppm relative to TMS; coupling constants (J) in Hz.
b) 500 MHz, CDCl3; chemical shifts in ppm relative to TMS; coupling constants (J) in Hz.
c) Overlapped signals.
ACKNOWLEDGEMENTS
The authors would like to thank Mr. Do Kyun Kim, Dr. Eun Jung Bang and Dr. Jung Ju Seo at Korea
Basic Science Institute for the measurements of NMR and MS spectra.

HETEROCYCLES, Vol. 78, No. 11, 2009
2835
REFERENCES AND NOTES
1. D. K. Ahn, Illustrated Book of Korean Medicinal Herbs, Koy-Hak Publishing Co., Korea, 1998, 607.
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