New polyphenols and triterpene from the pseudobulbs of pleione formosana

Article abstract of DOI:10.1002/jccs.200900122

Three new polyphenolic compounds including a dihydrophenanthrene, leioanthrenin (1), two bibenzyls, pleiobibenzynin A (2) and B (3), and a new cycloartane triterpenoid, (24R)-cyclomargenyl pcoumarate (4), together with eight known compounds, were isolated

Full text of DOI:10.1002/jccs.200900122

828
Journal of the Chinese Chemical Society, 2009, 56, 828-833
New Polyphenols and Triterpene from the Pseudobulbs of Pleione
formosana
Young-Ji Shiao (
), Wan-Ping Chen (
National Research Institute of Chinese Medicine, Taipei 112, Taiwan, R.O.C.
) and Yun-Lian Lin* (
)
Three new polyphenolic compounds including a dihydrophenanthrene, pleioanthrenin (1), two biben-
zyls, pleiobibenzynin A (2) and B (3), and a new cycloartane triterpenoid, (24R)-cyclomargenyl p-
coumarate (4), together with eight known compounds, were isolated from the pseudobulbs of Pleione
formosana. The structures of the new compounds were elucidated by extensively spectroscopic analysis.
Keywords: Pleione formosana; Pseudobulbs; Orchidaceae; Dihydrophenanthrenes; Bibenzyls;
Triterpenoids.
INTRODUCTION
Pleione formosana Hay. (Orchidaceae) is a perennial
bocodin C (8),6 arundin (9),7 3,3¢-dihydroxy-2,6-bis(4-
hydroxybenzyl)-5-methoxybibenzyl (10),8 2,6-bis(4-hy-
droxybenzyl)-3¢,5-dimethoxy-3-hydroxybibenzyl (11),8
(24R)-cyclomargenol (12).9
herb with rhizomes, corms, or root-stem tuberoids. The
pseudobulbs of P. formosana have been used as one of the
substitute of Shan-ci-gu, which is used in traditional Chi-
nese medicine to treat tumors.1,2 To the best of our knowl-
edge, there has been no phytochemical investigation on P.
formosana. As a part of our effort to search for bioactive
components from local indigenous herbs, we describe here-
in the first isolation of a dihydrophenanthrene (1), two
bibenzyls (2 and 3), and a cycloartane triterpenoid (4), to-
gether with 8 known compounds from the pseudobulbs of
P. formosana. Their structures were established mainly by
1D and 2D NMR and mass spectroscopic analysis.
Compound 1 was isolated as a pale yellow amor-
phous powder with a molecular formula C23H22O4 by HR-
EI-MS. The IR spectrum showed absorptions at 3374 (OH),
1598 and 1461 (benzenoid) cm-1. The UV absorption max-
ima at 269sh, 278, 297sh, and 317sh nm were characteristic
of a dihydrophenanthrene skeleton.10 The 1H NMR spec-
trum of 1 (see Table 1) showed two methoxyl groups at d
3.82 and 3.88 (3H each, s), an isolated aromatic proton at d
6.64 (s, H-3), an ABX system aromatic protons at d 8.00 (d,
J = 8.0 Hz, H-5), 6.60 (dd, J = 8.0, 2.0 Hz, H-6) and 6.62 (d,
J = 2.0 Hz, H-8), a p-substituted benzyl [d 6.63 and 6.88
(2H each, d, J = 8.0 Hz), and 3.94 (2H, s)], and signals as-
signable to the 9- and 10-methylene protons [d 2.58 and
2.50 (2H each, m) of dihydrophenanthrene. The NOE cor-
relations (Fig. 1) of methoxyl at d 3.82 to H-6 and H-8, and
methoxyl at d 3.88 to H-3¢(5¢) in the NOESY experiment of
1 revealed that the methoxyl functionality are attached to
C-7 and C-4¢, respectively. The assignments were further
confirmed by HMBC experiment (Fig. 1) from methoxyl (d
3.82) to C-7, from H-5 to C-6, C-4b, C-7, and C-8a, from
H-7¢ to C-1, C-1¢, C-2¢(6¢), C-2, C-10a; from methoxyl (d
3.88) to C-4¢, from H-3¢(5¢) to C-1¢, C-2¢(6¢), and C-4¢ (Fig.
1). Comparison of the 1H- and 13C-NMR data of 1 are simi-
lar to those of 1-(4-hydroxybenzyl)-7-methoxy-9,10-dihy-
drophenanthrene-2,7-diol3 except for a methoxyl group at
RESULTS AND DISCUSSION
The ethanolic extract of the pseudobulbs of P. for-
mosana was successively partitioned with EtOAc and n-
BuOH. The EtOAc and n-BuOH-soluble fractions were
separatedly subjected to silica gel column chromatography
(CC). Fractions rich in polyphenolic compounds were fur-
ther separated and purified on Sephadex LH-20 column
followed by C18 CC and semipreparative RP-18 HPLC to
give a new dihydrophenanthrene, pleioanthrenin (1), two
bibenzyls, pleiobibenzynin A (2) and B (3), and a cyclo-
artane triterpenoid, (24R)-cyclomargenyl p-coumarate (4),
together with 1-(4-hydroxybenzyl)-4,7-dimethoxy-9,10-
dihydrophenanthrene-2-ol (5),3 bulbocol (6),4 3¢,5-dihy-
droxy-2-(4-hydroxylbenzyl)-3-methoxybibenzyl (7),5 bul-
* Corresponding author. Tel: +886-2-2820-1999 ext. 6531; Fax: +886-2-2825-0743; E-mail: yllin@nricm.edu.tw

Polyphenols and Triterpenes are Isolated from Pleione formosana
J. Chin. Chem. Soc., Vol. 56, No. 4, 2009 829
4¢-position in place of a hydroxyl. From above results, the
structure of compound 1 was established as 1-(4-methoxy-
benzyl)-7-methoxy-9,10-dihydrophenanthrene-2,4-diol,
named pleioanthrenin.
Acetylation of 2 afforded pentaacetate [dH 2.11, 2.24, 2.24,
2.26, and 2.27 (3H each, s)], suggesting the presence of
five hydroxyl groups. The 1H NMR spectrum of 2 (see Ta-
ble 1) presented the signals of three p-hydroxybenzyl
groups [d 3.57 (2H, s), d 6.58 and 6.76 (2H each, d, J = 8.0
Hz); d 3.80 (2H, s), d 6.59 and 6.76 (2H each, d, J = 8.0
Hz); d 3.84 (2H, s), d 6.63 and 6.85 (2H each, d, J = 8.0
Hz)], an ABX-system 1,3,6-trisubstituted phenyl group [d
6.51 dd (J = 8.5, 2.0 Hz), d 6.57 d (J = 2.0 Hz), 6.77 d (J =
8.5 Hz)], four aliphatic bibenzyl methylene protons [d 2.42
Compound 2 had a pseudomolecular ion at m/z
561.2246 (M-H)- with the molecular formula of C36H33O6
as established by HR-ESI-MS. The UV absorption maxima
at 225 sh and 283 nm indicated the presence of bibenzyl.7
The IR spectrum showed absorption bands for hydroxyl
(3362 cm-1) and benzene ring (1600, 1513 and 1446 cm-1).

830 J. Chin. Chem. Soc., Vol. 56, No. 4, 2009
Shiao et al.
Table 1. 1H- and 13C-NMR spectral data for compounds 1~3 in CD3OD (d, ppm)
1
2
3
Position
1Ha
13Cb
1Ha
13Cb
1Ha
13Cb
1
118.3 s
156.0 s
96.1 d
142.8 s
119.4 s
156.3 s
98.2 d
140.8 s
124.9 s
154.1 s
121.1 s
2
3
6.64 s
4
156.3 s
120.1 s
126.1 s
130.5 d
113.6 d
157.4 s
114.6 d
140.6 s
30.9 t
6.46 s
4a
4b
5
8.00 d (8.0)c
158.4 s
120.2 s
31.7 t
157.7 s
125.7 s
33.4 t
6
6.60 dd (8.0,2.0)
7
2.66 m
2.42 m
2.67 m
2.35 m
8
6.62 d (2.0)
34.6 t
37.7 t
8a
9
2.58 m
2.50 m
10
10a
1¢
27.5 t
140.7 s
133.6 s
129.9 d
115.9 d
158.1 s
115.9 d
129.9 d
30.9 t
142.7 s
116.5 d
156.6 s
113.8 d
132.0 d
131.4 s
145.1 s
116.0 d
158.3 s
113.7 d
130.1 d
120.6 d
2¢
6.88 d (8.0)
6.63 d (8.0)
6.57 d (2.0)
6.47 dd (2.1,2.0)
3¢
4¢
6.51 dd (8.5,2.0)
6.77 d (8.5)
6.55 ddd (8.0,2.1,2.0)
7.00 t (8.0)
5¢
6.63 d (8.0)
6.88 d (8.0)
3.94 s
6¢
6.46 ddd (8.0,2.1,2.0)
7¢
1²
2²
3²
4²
5²
6²
7²
1²¢
2²¢
3²¢
4²¢
5²¢
6²¢
7²¢
1²²
2²²
3²²
4²²
5²²
6²²
7²²
OMe
134.2 s
129.9 d
115.9 d
155.9 s
115.9 d
129.9 d
31.1 t
133.4 s
130.0 d
115.9 d
156.2 s
115.9 d
130.0 d
32.0 t
6.85 d (8.0)
6.63 d (8.0)
6.90 d (8.2)
6.65 d (8.2)
6.63 d (8.0)
6.85 d (8.0)
3.84 s
6.65 d (8.2)
6.90 d (8.2)
4.03 s
134.1 s
129.8 d
115.8 d
155.9 s
115.8 d
129.8 d
31.0 t
133.4 s
130.2 d
116.0 d
156.2 s
116.0 d
130.2 d
30.1 t
6.77 d (9.0)
6.58 d (9.0)
7.02 d (8.0)
6.66 d (8.0)
6.59 d (9.0)
6.76 d (9.0)
3.80 s
6.66 d (8.0)
7.02 d (8.0)
4.03 s
133.6 s
130.6 d
116.1 d
155.9 s
116.1 d
130.6 d
37.9 t
134.2 s
129.9 d
115.9 d
156.2 s
115.9 d
129.9 d
31.9 t
6.76 d (8.0)
6.58 d (8.0)
6.85 d (8.4)
6.63 d (8.4)
6.58 d (8.0)
6.76 d (8.0)
3.57 s
6.63 d (8.4)
6.85 d (8.4)
3.94 s
3.82 s
3.88 s
56.2 q
56.3 q
3.72 s
55.9 q
3.46 s
62.2 q
Spectra recorded at a 500 MHz and b 125 MHz in CD3OD at 25 °C. c Coupling constants are presented in Hz.
and 2.66 (each 2H, m)], along with a methoxyl group [d
3.72 (3H, s)]. The data was also supported by the 13C NMR
and DEPT experiment, which was analyzed by 1H-13C shim
correlations by HMQC experiment. The location of hy-
droxyl, methoxyl and p-hydoxybenzyl were determined by
1D NOE, NOESY (Fig. 2) and HMBC (Fig. 2). Irradiation
of the methoxyl at d 3.72 caused the NOE enhancement of
H-4 (d 6.46 s), H-7²¢ (d 3.80 s) and H-2²¢(6²¢) (d 6.76 d), ir-
radiation of H-8 (d 2.42 m) resulted the NOE with H-7²² (d
3.57 s) and H-2¢ [d 6.57 (d, J = 2.0 Hz)], and irradiation of

Polyphenols and Triterpenes are Isolated from Pleione formosana
J. Chin. Chem. Soc., Vol. 56, No. 4, 2009 831
H-7 (d 2.66 m) caused the NOE enhancements of H-7² (d
3.84 s) and H-7²¢ (d 3.80 s) in 1D NOE experiments indi-
cating the symmetrical substituted the p-hydroxybenzyls
on C-2 and C-6, the other p-hydroxybenzyl on C-6¢, and the
methoxyl functionality attached to C-5, respectively. The
HMBC spectrum revealed significant correlations between
methoxyl (dH 3.72 s) and carbons at dC 158.4 (C-5), be-
tween H-8 (dH 2.42 m) and carbons at dC 31.7 (C-7), 116.5
(C-2¢), 131.4 (C-6¢), 142.7 (C-1¢), and 142.8 (C-1), be-
tween H-7 (dH 2.66 m) and carbons at dC 34.6 (C-8), 119.4
(C-2), 120.2 (C-6), and 142.7 (C-1¢), and 142.8 (C-1), be-
tween H-7² (dH 3.84 s) and carbons at dC 119.4 (C-2), 129.9
(C-2²(6²)), 134.2 (C-1²), 142.8 (C-1), and 156.3 (C-3), be-
tween H-7¢² (dH 3.80 s) and carbons at dC 120.2 (C-6),
129.8 (C-2¢²(6²¢)), 134.1 (C-1²¢), 142.8 (C-1), and 158.4
(C-5), between H-7²² (dH 3.57 s) and carbons at dC 130.6
[C-2²²(6²²)], 131.4 (C-6¢), 132.0 (C-5¢), 142.7 (C-1¢), and
133.6 (C-1²²), between H-4 (dH 6.46 s) and carbons at dC
119.4 (C-2), 120.2 (C-6), 156.3 (C-3), 158.4 (C-5), and be-
tween H-4¢ [dH 6.51 (8.5, 2.0 Hz)] and carbons at dC 116.5
(C-2¢), 132.0 (C-5¢), 131.4 (C-6¢), and 156.6 (C-3¢). From
above results, the structure of 2 was assigned as 3,3¢-dihy-
droxy-5-methoxy-2,6,6¢-tri(p-hydroxybenzyl)bibenzyl,
named pleiobibenzynin A.
mula with compound 2 as determined by negative HR-ESI-
MS. The IR and UV spectra of 3 were similar to those of 2.
The 1H, 13C and DEPT spectra of 3 presented three p-hy-
droxybenzyl, four bibenzyl methylene protons, a methoxyl,
and a system of 1,3-substituted phenyl protons. Pentaace-
tate [dH 2.08, 2.25, 2.25, 2.26, and 2.27 (3H each, s)] from
its acetylation suggested the presence of five hydroxyl
groups. The difference between compounds 2 and 3 was
the position of one of the p-hydroxybenzyl at C-6¢ in 2 in-
stead of C-4 in 3. These results were confirmed by selected
NOE irradiations. The key NOE correlations in a NOESY
experiment and HMBC correlations were shown in Fig. 3.
The structure of the new compound was thus assigned as
3,3¢-dihydroxy-5-methoxy-2,4,6-tri-(p-hydroxybenzyl)-
bibenzyl.
Compound 4 was obtained as colorless powder, [a] D20
+58° (c = 0.2, MeOH). A molecular formula of C41H59O3
was determined by negative HR-ESI-MS (m/z 599.4454
[M-H]-) with 12 degrees of unsaturation. The IR spectra
displayed the presence of hydroxyl (3376 cm-1) and an
a,b-unsaturated ester (1705 and 1257 cm-1). The 13C-NMR
and DEPT showed 41 carbons including seven methyls,
thirteen methylenes (one sp2), twelve methines (one oxy-
genated, 6 sp2), eight quaternary carbons (two sp2 and one
1
Pleiobibenzynin B (3) has the same molecular for-
oxygenated sp2), and one conjugated carbonyl. The H
NMR spectrum showed signals indicating two characteris-
tic pair of high field doublet of cyclopropanyl methylene
protons [d 0.37 (1H, d, J = 4.0 Hz), 0.61 (1H, d, J = 4.0 H)],
five tertiary methyls [d 0.90, 0.91, 0.98, 0.98, 1.63 (3H
each, s)], a secondary methyl [d 0.87 (3H, d, J = 6.5 Hz)], a
primary methyl [d 0.82 (3H, t, J = 7.5 Hz)], an exo-meth-
ylenes [d 4.65 and 4.74 (1H each, br s)], an oxygenated
methine [d 4.71 (1H, dd, J = 9.0, 8.0 Hz)], an AA¢BB¢ sys-
tem of aromatic protons [d 6.84 and 7.43 (2H each, d, J =
Fig. 1. Key NOE («) and HMBC (®) correlations ob-
served for 1.
Fig. 3. Key NOE («) and HMBC (®) correlations ob-
served for 3.
Fig. 2. Key NOE («) and HMBC (®) correlations ob-
served for 2.

832 J. Chin. Chem. Soc., Vol. 56, No. 4, 2009
Shiao et al.
8.5 Hz)], and an a,b-unsaturated olefinic protons [d 6.31
and 7.61 (1H each, d, J = 16.0 Hz)]. The HMQC spectrum
facilitated the assignment of the protonated carbons. From
above data in addition to the coumaroyl moiety (with six
degrees of unsaturation), the remaining six degrees of un-
saturation suggested compound 4 to be a cycloartane-type
triterpene like 24-ethyl-25-methylenecycloartanol.9 The
configuration of OH-3 must be in b-equatorial orientation,
since H-3 had a bigger coupling constant [d 4.71 (1H, dd, J
= 9.0, 8.0 Hz)]. The assignment was further confirmed by
the observation of main NOE correlation from H-3 and H-5
(dH 1.54 m), and key HMBC correlations between H-3 and
carbonyl (dC 167.6), C-28 (dC 19.5), and C-29 (dC 15.6);
between H-a [dH 6.31 (d, J = 16.0)] and C-b (dC 144.3),
C-1¢ (dC 127.6), and carbonyl (dC 167.6); between H-19 [dH
0.37 and 0.61 (1H each, d, J = 4.0 Hz)] and C-1 (dC 26.1),
C-5 (dC 48.1), C-8 (dC 47.5), C-9 (dC 20.4), C-10 (dC 26.2),
and C-11 (dC 26.8); between H-27 (dH 1.63 s) and C-24 (dC
49.8), C-25 (dC 147.8), and C-26 (dC 111.6); and between
H-32 [dH 0.82 (t, J = 7.5 Hz) and C-24 and C-31 (dC 30.0)].
The absolute configuration at C-24 of 4 was accomplished
by measuring the circular dichroism (CD) curve [CD[q]283
-134.7°] and comparing with those of (24R)-cyclolaudenyl
acetate and (24R)-cyclomargenyl acetate,9 and concluded
to have a (24R)-configuration. This is a first isolation from
natural product.
Taiwan University, Ren-Ai Township, Nantou County,
Aug in 2006. The plant was identified by Mr. Jun-Chih Ou,
a previous associate research fellow of National Research
Institute of Chinese Medicine.
Extraction and Isolation
Slices of pseudobulbs of P. formosana (3.2 kg) were
extracted at 60 °C using 95% EtOH overnight (3 ´ 40 L).
The EtOH extract (164 g) was taken up in H2O, and parti-
tioned with EtOAc (1:1, v/v) to give an EtOAc-soluble
fraction (52.0 g) and aqueous phase. The aqueous phase
was further extracted with n-BuOH to obtain n-BuOH-sol-
uble (30.2 g) and H2O-soluble (131.0 g) fractioncts. Both
EtOAc and n-BuOH fractions were separatedly subjected
to column chromatography over silica gel (using hexane-
EtOAc-20% EtOAc/MeOH gradient for EtOAc extract,
and 25% EtOAc/hexane ~ EtOAc-50% EtOAc/MeOH for
n-BuOH extract). Fractions 50% EA/hexane ~ 50% EA/
MeOH eluate rich in polyphenols were combined and re-
chromatographed over Sephadex LH-20 column with
MeOH as eluent to yield four fractions (II~IV). Fraction I
was further purified over silica gel column with 20~35%
EtOAc/hexane to give (24R)-cyclomargenyl p-coumarate
(4) (72 mg) and (24R)-cyclomargenol (12) (296 mg). Frac-
tions II~IV were repeatedly subjected to RP-18 (80%
MeOH~MeOH) column, followed by semi-preparative
HPLC using 80% MeOH/H2O as mobile phase (2 mL/min)
to give 1 (26 mg), 2 (15 mg), 3 (25 mg), 5 (21 mg), 6 (28
mg), 7 (25 mg), 8 (14 mg), 9 (38 mg), 10 (82 mg), and 11
(23 mg).
EXPERIMENTAL SECTION
General Method
IR spectra were recorded on a Nicolet Avatar 320
FT-IR spectrophotometer. UV spectra were measured on a
Hitachi U-3310 spectrophotometer. NMR spectra were run
on a Varian unity INOVA-500 and Bruker AVANCE 400
spectrometers. Mass spectra (EI-MS, ESI-MS and HR-
ESI-MS) were recorded on a Finnigan LCQ, Finnigan Mat-
95 XL, respectively. Optical rotation was recorded on a
Jasco DIP-370. Column chromatography were performed
using Merck silica gel (kieselgel 60), SephadexÔ LH-20
(GE Healthcare) and RP-18 (Cosmosil 75C18-PREP). Futher
purifications were subjected by HPLC on RP-18 column
(Merck, LiChrospher 100, RP-18e (5 mm), 250 ´ 10 mm).
Si gel 60F254 (Merck) was used for TLC with 35% EA/hex-
ane or 10% MeOH/CHCl3 as developing solvent.
Plant Material
Pleioanthrenin (1)
Pale yellow amorphous powder; IR (KBr) umax 3374,
1605, 1596, 1509, 1461, 1239, 1081, 1042, 816 cm-1; UV
(MeOH) lmax (log e) 269sh (3.94), 278 (4.03), 297sh
(3.93), 317sh (3.75) nm; 1H NMR (500 MHz, methanol-d4)
and 13C NMR: see Table 1; Main NOE and key HMBC cor-
relations see Fig. 1; EIMS m/z 362 (M)+ (100), 270 (50),
256 (25), 107 (18); HREIMS m/z 362.1513 (calcd for
C23H22O4 362.1519).
Pleiobibenzynin A (2)
Colorless amorphous powder; IR (KBr) umax 3362,
1600, 1513, 1446, 1232, 1172, 1109, 1046, 816 cm-1; UV
(MeOH) lmax nm (log e): 225 sh (3.64), 283 (3.04) nm; 1H
NMR (500 MHz, methanol-d4) and 13C NMR: see Table 1;
Main NOE and HMBC correlations: see Fig. 2; ESIMS
negative mode m/z 561 (M-H)-; negative-ion HRESIMS
m/z 561.2246 (calcd for C36H33O6 561.2278).
The pseudobulbs of P. formosana was purchased
from Mei-Feng highland experimental farm of National

Polyphenols and Triterpenes are Isolated from Pleione formosana
J. Chin. Chem. Soc., Vol. 56, No. 4, 2009 833
Pleiobibenzynin B (3)
respectively. Usual work-up gave pentaacetate of 2 (2a):
Colorless amorphous; 1H NMR (500 MHz, chloroform-d)
d 2.11, 2.24, 2.24, 2.26, and 2.27 (3H each, s), 3.72, 3.77,
and 3.97 (2H each, s), 3.73 (3H, s), 6.59 (1H, s), 6.69 (1H,
d, J = 2.0 Hz), 6.82 (1H, dd, J = 8.0, 2.0 Hz), 6.89 (2H, d, J
= 8.0 Hz), 6.90 (3H, d, J = 8.0 Hz), 6.91 (2H, d, J = 8.0 Hz),
6.93 (2H, d, J = 8.0 Hz), 6.94 (2H, d, J = 8.0 Hz), 6.96 (2H,
d, J = 8.0 Hz), 6.99 (2H, d, J = 8.0 Hz); pentaacetate of 3
(3a): Colorless amorphous; 1H NMR (500 MHz, chloro-
form-d) d 2.08, 2.25, 2.25, 2.26, and 2.27 (3H each, s), 3.51
(3H, s), 3.93, 4.07, and 4.07 (2H each, s), 6.62 (1H, dd, J =
2.1, 2.0 Hz), 6.72 (1H, ddd, J = 8.0, 2.1, 2.0 Hz), 6.82 (1H,
ddd, J = 8.0, 2.1, 2.0 Hz), 6.92 (2H, d, J = 8.5 Hz), 6.95
(2H, d, J = 8.5 Hz), 6.95 (2H, d, J = 8.5 Hz), 7.01 (2H, d, J =
8.5 Hz), 7.03 (2H, d, J = 8.5 Hz), 7.04 (1H, t, J = 8.0 Hz),
7.12 (2H, d, J = 8.5 Hz).
Colorless amorphous powder; IR (KBr) umax 3346,
1614, 1589, 1507, 1455, 1238, 1170, 1082, 1047, 816 cm-1;
UV (MeOH) lmax (log e) 225 sh (3.65), 283 (3.02) nm; 1H
NMR (500 MHz, methanol-d4) and 13C NMR see Table 1;
Main NOE and HMBC correlations see Fig. 3; ESIMS neg-
ative mode m/z 561 (M-H)-; negative-ion HRESIMS m/z
561.2222 (calcd for C36H33O6, 561.2278).
(24R)-cyclomargenyl p-coumarate (4)
Colorless amorphous powder; [a] 2D0 +58° (c = 0.2,
MeOH); IR (KBr) umax 3376, 2928, 2867, 1705, 1601,
1585, 1513, 1445, 1374, 1257, 1167, 1025, 900, 830 cm-1;
1H NMR (500 MHz, chloroform-d): d 0.37 and 0.61 (1H
each, d, J = 4.0 Hz, H-19), 0.82 (3H, t, J = 7.5 Hz, H-32),
0.87 (3H, d, J = 6.5 Hz, H-21), 0.90 (3H, s, H-28), 0.91
(3H, s, H-30), 0.98 (3H, s, H-18), 0.98 (3H, s, H-29), and
1.63 (3H each, s, H-27), 4.65 and 4.74 (1H each, br s, H-
26), 4.71 (1H, dd, J = 9.0, 8.0 Hz, H-3a), 5.62 (1H, br s,
OH), 6.31 and 7.61 (1H each, d, J = 16.0 Hz, H-a, b), 6.84
and 7.43 (2H each, d, J = 8.5 Hz, H-3²(5²), 2²(6²)); 13C
NMR (125 MHz, chloroform-d): d 12.3 q (C-32), 15.6 q
(C-29), 18.0 q (C-27), 18.2 q (C-30), 18.5 q (C-21), 19.5 q
(C-28), 20.4 s (C-9), 21.2 t (C-6), 25.7 q (C-18), 26.1 t
(C-1), 26.2 s (C-10), 26.8 t (C-11), 26.8 t (C-16), 27.2 t
(C-7), 28.3 t (C-19), 30.0 t (C-31), 30.1 t (C-23), 31.9 t
(C-22), 33.1 t (C-12), 34.2 t (C-2), 35.8 t (C-15), 36.1 d
(C-20), 39.9 s (C-13), 45.5 s (C-14), 47.5 d (C-8), 48.1 d
(C-5), 49.0 s (C-4), 49.8 d (C-24), 52.5 d (C-17), 80.9 d
(C-3), 111.6 t (C-26), 116.1 d (C-3¢(5¢)), 116.6 d (C-a),
127.6 s (C-1¢), 130.2 d (C-2¢(6¢)), 144.3 d (C-b), 147.8 s
(C-25), 157.8 s (C-4¢), 167.6 s (C=O); Main NOE: H-3/H-
5, H-29; H-18/H-16; H-19/H-1, H-11; and H-28/H-2; Key
HMBC correlations: H-3/C=O, C-28, C-29; H-a/C-b, C-
1¢, C=O; H-19/C-1, C-5, C-9, C-10; H-21/C-17, C-20,
C-22; H-26/C-24, C-25, C-27; H-27/C-24, C-25, C-26;
H-30/C-8, C-13, C-14, C-15; and H-32/C-24 and C-31.
ESIMS negative mode: 599 [M-H]-; negative-ion HRESIMS
m/z 599.4374 (calcd for C41H59O3 599.4467); CD[q]283
-134.7°.
ACKNOWLEDGMENT
This work was supported by the National Science
Council of the Republic of China (NSC 94-2323-B-077-
001 and NSC 95-2323-B-077-001).
Received April 3, 2009.
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Acetylation of 2 and 3
Compound 2 or 3 (4 mg) was allowed to react with
Ac2O (1.0 mL) in pyridine (0.5 mL) at 60 °C for overnight,