Structure and stereochemistry of epoxyserratanes from the cuticle of Picea jezoensis var. jezoensis

Article abstract of DOI:10.1021/np000630e

Three new epoxytriterpenes, 14β, 15β-epoxy-21β-hydroxyserratan-3-one (1), 13α, 14α-epoxy-21α-methoxyserratan-3-one (2), and 13α,14α-epoxy-3β-methoxyserratan-21β-ol (3), were isolated together with two known triterpenoids, 21α-methoxyserrat-13-en-3-one (4) and 21β-hydroxyserrat-14-en-3-one (5), from the cuticle of Picea jezoensis var. jezoensis. The structures of these new compounds were established on the basis of spectral data (NMR, MS) and single-crystal X-ray analyses (1 and 2) and partial synthesis (2 and 3).

Full text of DOI:10.1021/np000630e

1
044
J . Nat. Prod. 2001, 64, 1044-1047
Str u ctu r e a n d Ster eoch em istr y of Ep oxyser r a ta n es fr om th e Cu ticle of P icea
jezoen sis va r . jezoen sis
,
†
†
†
†
†
Reiko Tanaka,* Kazuhiro Tsujimoto, Yasuko In, Toshimasa Ishida, Shunyo Matsunaga, and
Yukimasa Terada‡
Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, J apan, and Faculty of
Pharmaceutical Sciences, Meijo University, 150 Yagotoyama, Tenpaku-ku, Nagoya, Aichi 468-8503, J apan
Received December 29, 2000
Three new epoxytriterpenes, 14â,15â-epoxy-21â-hydroxyserratan-3-one (1), 13R,14R-epoxy-21R-methoxy-
serratan-3-one (2), and 13R,14R-epoxy-3â-methoxyserratan-21â-ol (3), were isolated together with two
known triterpenoids, 21R-methoxyserrat-13-en-3-one (4) and 21â-hydroxyserrat-14-en-3-one (5), from the
cuticle of Picea jezoensis var. jezoensis. The structures of these new compounds were established on the
basis of spectral data (NMR, MS) and single-crystal X-ray analyses (1 and 2) and partial synthesis (2
and 3).
The CH
2
Cl
2
extract of the cuticle of Picea jezoensis (Sieb.
Resu lts a n d Discu ssion
et Zucc.) Carr. var. jezoensis (Pinaceae) contained 13
triterpenes including 3â-methoxyserrat-14-en-21â-ol, 21R-
Compound 1 was assigned the molecular formula
30 48 3
C H O , by HREIMS. Its IR spectrum showed absorption
1
hydroxy-3â-methoxyserrt-14-en-30-al, 14â,15â-epoxy-3â-
1
bands for a hydroxyl group and a cyclohexanone. The H
and 13C NMR spectra (Table 1) exhibited signals for seven
singlet methyl groups, 10 methylene groups, four methine
groups, five quaternary carbons, an axial secondary hy-
droxyl group, an oxygenated methine, and an oxygenated
2
methoxyserratan-21-one and the corresponding 21â-ol, and
3
2
1R-methoxyserrat-13-en-3,15-dione. Investigation of the
extract has led to the isolation of novel epoxyserratanes,
-3, together with two known compounds, 21R-methoxy-
serrat-13-en-3-one (4) and 21â-hydroxyserrat-14-en-3-one
5), identical in all respects with the corresponding au-
1
2
quaternary carbon attributable to an epoxy ring and a
(
saturated ketone, while no signal was observed for a double
bond. Except for the presence of a ketone and the absence
thentic samples already isolated from the stem bark of P.
jezoensis (Sieb. et Zucc.) Carr. var. hondoensis (Mayr.)
Rehder.4 This paper deals with the structure elucidation
of compounds 1-3.
1
13
of a methoxy group, the H and C NMR and EIMS spectra
of 1 were closely similar to those of 14â,15â-epoxy-3â-
methoxyserratan-21â-ol.2 Along with the chemical shift
values and signal pattern of the methine proton geminal
to the hydroxyl group, these data indicated that 1 must be
,5
1
4,15-epoxy-21â-hydroxyserratan-3-one. The stereochem-
istry was determined by single-crystal X-ray analysis and
NOESY measurement. The ORTEP diagram (Figure 1)
indicated 1 to be 14â,15â-epoxy-21â-hydroxyserratan-3-one,
having a flat conformation of the skeletal system due to
the presence of a cis-fused chairlike/half-chair conformation
of the C/D rings, together with a deformed-chair for ring
A. The NOESY spectrum exhibited cross correlations
among signals of Me-23 with H-6R, Me-24 with H-2â and
H-6â, Me-25 with H-2â and H-12â, H-15R with H-27â,
H-27R with H-7R and H-9R, and H-27â with H-7R and
H-7â, indicating 1 to have a three-dimensional structure
identical with that obtained from the X-ray analysis.
Oxidation of 21â-hydroxyserrat-14-en-3-one (5) with m-
3
chloroperbenzoic acid (MCPBA) in CHCl furnished the
corresponding epoxide, identical in all respects with 1, in
almost quantitative yield.
Compounds 2 and 3 were assigned the molecular for-
mulas C31
H
50
1
O
3
and C31
H
52
O
3
, respectively, by HREIMS.
13
The IR and H and C NMR spectra of 2 (Table 1) revealed
signals due to seven singlet methyl groups, 11 methylene
3
groups, three methine groups, five sp quaternary carbons,
3
an equatorial secondary methoxy group, and two sp
quaternary carbons combined with one oxygen atom. The
1
13
H and C NMR spectra of 3 (Table 1) were similar to those
of 2, except for the absence of a ketone and the presence of
a secondary hydroxyl group, and exhibited signals for an
equatrial methoxy group, a secondary hydroxyl group, and
*
To whom correspondence should be addressed. Tel and Fax: (+81)-
7
26-90-1084. E-mail: tanakar@oysun01.oups.ac.jp.
†
Osaka University of Pharmaceutical Sciences.
Meijo University.
‡
3
two sp quaternary carbons geminal to an ether oxygen.
1
0.1021/np000630e CCC: $20.00
© 2001 American Chemical Society and American Society of Pharmacognosy
Published on Web 07/26/2001

Epoxyserratanes from the Cuticle of Picea
J ournal of Natural Products, 2001, Vol. 64, No. 8 1045
Ta ble 1. 1H and 13C NMR Data of Compounds 1, 2, and 3 in CDCl3a
1
2
3
1H
13C
1H
13C
1H
13C
1
1
2
2
3
4
5
6
6
7
7
8
9
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
3
R
â
R
â
1.48, m
2.28, m
2.46, dd (9.2, 3.1)
2.48, dd (9.2, 5.6)
39.6, t
1.45, m
1.98, m
2.43, m
2.49, m
39.6, t
0.84, m
1.83, m
1.81, m
1.42, m
38.5, t
34.0, t
33.9, t
22.2, t
218.1, s
47.3, s
55.0, d
19.7, t
218.1, s
47.1, s
54.3, d
19.7, t
2.62, dd (12.2, 4.4)
88.3, d
38.8, s
55.8, d
18.2, t
R
R
â
R
â
1.40, m
1.43, m
1.55, m
1.43, m
1.45, dd (13.1, 2.0)
1.46, m
1.55, m
1.22, m
1.49, m
0.70, dd (13.1, 1.4)
1.46, m
1.46, m
1.43, m
1.18, m
43.3, t
43.7, t
44.8, t
1.20, td (13.0, 3.6)
37.0, s
62.6, d
39.0, s
25.9, t
37.0, s
64.8, d
38.0, s
22.3, t
37.1, s
65.7, d
38.4, s
21.5, t
R
0
0.85, dd (11.1, 1.2)
0.88, dd (10.7, 1.4)
0.74, dd (12.5, 1.5)
1R
1â
2R
2â
3â
4
5R
5â
6R
6â
7â
8
9R
9â
0R
0â
1R
1â
2
3
4
5
6
7R
7â
8
9
0
1.93, m
1.37, m
1.93, m
1.07, m
1.64, m
1.36, m
2.52, dd (15.6, 8.9)
1.02, m
1.68, m
1.36, m
2.52, dd (15.8, 8.9)
0.98, m
27.1, t
34.0, t
33.8, t
1.48, dd (12.8, 4.1)
56.6, d
61.1, s
59.3, d
72.5, s
65.5, s
36.8, t
72.9, s
65.7, s
36.5, t
2.82, brs
1.96, dt (14.1, 3.0)
1.78, ddd (14.1, 12.1, 6.0)
1.23, m
1.29, m
0.87, dd (11.1, 1.6)
1.93, dt (14.4, 3.3)
1.83, m
1.20, m
1.20, m
1.35, m
1.70, ddd (14.6, 13.1, 2.1)
1.96, m
1.47, m
22.7, t
16.9, t
16.8, t
37.9, d
35.2, s
31.7, t
53.2, d
37.7, s
34.3, t
46.2, d
37.9, s
29.3, t
1.52, m
1.43, m
1.78, ddd (14.8, 4.5, 2.7)
1.56, m
3.41, t (2.7)
1.83, dt (13.1, 3.6)
1.58, m
1.55, m
2.02, m
1.70, m
1.50, m
2.05, m
25.1, t
75.6, d
23.2, t
88.0, d
26.4, t
75.3, d
1.96, m
2.71, dd (11.8, 4.4)
3.35, t (2.6)
37.7, s
26.9, q
20.8, q
16.3, q
19.9, q
55.2, t
39.1, s
27.3, q
20.8, q
16.7, q
20.4, q
53.7, t
38.1, s
28.0, q
16.2, q
16.4, q
21.0, q
54.0, q
1.08, s
1.03, s
0.91, s
1.12, s
0.80, d (14.2)
1.93, d (14.2)
0.75, s
0.90, s
0.94, s
1.08, s
1.03, s
0.89, s
1.09, s
1.58, d (14.9)
1.58, d (14.9)
1.01, s
0.71, s
0.95, s
0.94, s
0.74, s
0.82, s
1.08, s
1.54, d (14.5)
1.54, d (14.5)
1.00, s
0.80, s
0.92, s
14.8, q
22.8, q
27.7, q
16.5, q
16.5, q
28.0, q
57.6, q
16.3, q
22.2, q
27.9, q
57.5, q
OMe
3.35, s
3.35, s
a
Assignments based on DEPT, COSY, HMQC, HMBC, and NOESY experiments.
corresponding to ions characteristic of the fragmentation
of C-13,14-epoxyserratanes.
Oxidation of 21R-methoxyserrat-13-en-3-one (4) with
m-chloroperbenzoic acid (MCPBA) in CHCl furnished the
3
corresponding epoxide, identical in all respects with 2, in
almost quantitative yield. Treatment of 3â-methoxyserrat-
1
4-en-21â-ol (6) with concentrated H
2 4
SO in glacial acetic
acid, followed by alkaline hydrolysis of the resulting acetate
6
,7
(
6a ), yielded 3â-methoxyserrat-13-en-21â-ol (6b). Oxida-
tion of 6b with MCPBA afforded the corresponding epoxy
derivative identical in all respects with those of compound
3
in almost quantitative yield.
Compounds 2 and 3 provide two possible pairs of
F igu r e 1. ORTEP drawing of compound 1.
conformers, by changing the epoxy ring from an R- to a
â-orientation. The stereochemistry was examined by single-
crystal X-ray analysis of 2 and NOESY spectra of 2 (Figure
The HMBC spectra of 2 and 3 revealed the gross structures,
suggesting the ketone, the secondary methoxy group, and
the epoxy ring to be placed at C-3 and C-21R and between
the C-13 and C-14 positions for 2, and the secondary
methoxy group, the secondary hydroxyl group, and the
epoxy ring to be placed at C-3â and C-21â and between
the C-13 and C-14 positions for 3, respectively. Acetylation
of 3 furnished a monoacetate (3a ), in which the hy-
droxymethine proton signal was shifted to δ 4.65 (1H, t, J
2
2
) and 3 (Figure 3). The ORTEP diagram (Figure 4) showed
to have the structure 13R,14R-epoxy-21R-methoxyserra-
tan-3-one with a “bent-up” conformation, viz., the trans-
fused half-chair/chair form of the D/E rings was lifted
upward ca. 85° from the plane of the A/B/C rings due to
the presence of an R-oriented epoxy ring in the joint of the
cis-fused chair-like/half-chair form of the C/D rings. Fur-
thermore, ring A, which contains a 4,4-dimethyl-3-one
)
2.6 Hz). The EIMS of 2 and 3 showed fragment peaks

1
046 J ournal of Natural Products, 2001, Vol. 64, No. 8
Tanaka et al.
a J asco DIP-1000 digital polarimeter. IR spectra were recorded
1
using a Perkin-Elmer 1720X FT-IR spectrophotometer. H and
1
3
C NMR spectra were obtained using a J EOL GX-500
spectrometer with standard pulse sequences, operating at 500
and 125 MHz, respectively. CDCl was used as the solvent and
3
TMS as the internal standard. EIMS were recorded on a
Hitachi 4000H double-focusing mass spectrometer (70 eV).
Column chromatography was carried out over silica gel (70-
2
30 mesh). Fractions obtained from column chromatography
were monitored by TLC (silica gel 60 HF254). Preparative TLC
was carried out on Merck silica gel PF254 plates (20 × 20 cm,
0
.5 mm thick).
P la n t Ma ter ia l. Cuticles of P. jezoensis (sieb. et Zucc.) Carr.
var. jezoensis were collected at ca. 1000 m in the mountains
of Okujyozankei district under the management of National
Hokkaido Forestry Bureau, Sapporo City, J apan, in August
1
997. A voucher specimen (PJ J -97-01) is deposited at the
Herbarium of the Laboratory of Medicinal Chemistry, Osaka
University of Pharmaceutical Sciences.
Extr a ction a n d Isola tion . In previous papers, we reported
the isolation of several triterpene constituents from the CH
Cl extract of the cuticle of P. jezoensis (sieb. et Zucc.) Carr.
var. jezoensis.
extraction and reexamined the constituents. The air-dried and
chopped cuticle of P. jezoensis (8.5 kg) was extracted with CH
Cl (10 L) employing an automatic glass percolator for 24 h at
0 °C. The CH Cl solution was then evaporated under reduced
2
-
2
1
-3
We have now enlarged the scale of the
F igu r e 2. NOESY correlations (dashed arrow) of 2.
2
-
2
4
2
2
pressure, and the resulting dark green residue (530.7 g) was
subjected to silica gel (10 kg) column chromatography. Elution
of the column with CHCl
g), C (32.4 g), and D (40.3 g) from fractions 7-17, 23-27, 28-
0, and 41-50 (each 2 L). Elution was continued with CHCl -
3
afforded residues A (61.8 g), B (15.5
4
3
EtOAc (10:1) to give residue E (45.3 g) from fractions 51-80.
Repeated CC of residue A on silica gel (1.8 kg) afforded a
crystalline solid (fractions 15-33, 2.23 g), which was crystal-
lized from MeOH-CHCl
25 °C, [R] +110 (c 1.35, CHCl
residue D on silica gel (900 g) afforded compound 5 (186 mg),
3
to give compound 4, 1.82 g, mp 223-
4
2
D
3
). Rechromatography of
5
mp 261.5-264 °C, [R]
125 mg), from fractions 56-58 and 92-98. Repeated column
chromatography of residue E on silica gel (2 kg) furnished
residue C
D
+19 (c 0.33, CHCl
3
), and compound 1
(
1
(1.45 g) from fractions 17-30, which was rechro-
matographed on silica gel (100 g) to furnish compounds 2 (226
mg) and 3 (123 mg).
F igu r e 3. NOESY correlations (dashed arrow) of 3.
1
4â,15â-Ep oxy-21â-h yd r oxyser r a ta n -3-on e (1): needles;
mp 310-312 °C (MeOH-CHCl ); [R] -14.5 (c 0.52); IR νmax
cm 3470, 2934, 2872, 1702 (six-membered ring CdO), 1457,
3
D
-
1
1
1
387, and 1365 (gem dimethyl), 1082, 1067, 1035 and 996; H
1
3
+
and C NMR, see Table 1; EIMS m/z (rel int) 456 (57) [M] ,
+
+
4
CH
4
(
41 (19) [M - Me] , 438.3488 (9) [M - H
2
O] , 425 (6) [M -
+
+
+
2
OH] , 423 (11) [M - Me - H
2
O] , 420 (7) [M - 2H
2
O] ,
O] , 303
+
+
09 (26) [M - H
2
O - CO] , 405 (26) [M - Me - 2H
2
4), 289 (8), 273 (13), 257 (10), 237 (31), 232 (17), 224 (89), 219
(
9), 209 (100), 205 (18), 191 (16), 154 (35), 136 (64) 121 (54);
+
HREIMS m/z 456.3608 [M] (C30
H
48
O
3
requires 456.3603).
1
3r,14r-Ep oxy-21r-m eth oxyser r a ta n -3-on e (2): prisms;
mp 219-222 °C (MeOH-CHCl
3
); [R]
D
-98 (c 0.83); IR νmax
-
1
cm 2954, 2872, 1709 (six-membered ring CdO), 1464, 1386
1
and 1363 (gem dimethyl), 1181, 1103, 1000, 987, 943; H and
C NMR, see Table 1; EIMS m/z (rel int) 470 (6) [M] ,
1
3
+
+
+
4
[
2
52.3652 (8) [M - H O] , 438.3499 (2) [M - MeOH] , 420 (5)
2
+
+
M - MeOH - H
2
O] , 405 (13) [420 - Me] , 351 (13), 303 (6),
85 (2), 205 (8), 201 (11), 168 (22), 136 (100), 121 (42); HREIMS
+
m/z 470.3758 [M] (C31
P r ep a r a tion of 2 fr om 4. A solution of MCPBA (52 mg)
in dry CHCl (5 mL) was gradually added to a solution of 4
83 mg) in dry CHCl (15 mL) under stirring at room temper-
ature. After standing for 24 h, the reaction mixture was
washed with 5% NaHSO , 5% Na CO , and H O and the
organic layer dried over Na SO . Evaporation of the solvent
50 3
H O requires 470.3756).
F igu r e 4. ORTEP drawing of compound 2.
3
grouping, adopts a deformed-boat conformation. Thus, 3
was determined to be 13R,14R-epoxy-3â-methoxyserratan-
(
3
2
1â-ol.
3
2
3
2
2
4
Exp er im en ta l Section
under reduced pressure yielded a residue, which was purified
Gen er a l Exp er im en ta l P r oced u r es. Melting points were
determined on a Yanagimoto micro-melting point apparatus
and are uncorrected. Optical rotations were measured using
by PTLC (CHCl -MeOH, 30:1) to give a crystalline solid.
3
Recrystallization from MeOH-CHCl afforded 4a (70 mg) as
3
prisms, mp 219-222 °C; [R] -97 (c 0.45). It was identified as
D

Epoxyserratanes from the Cuticle of Picea
J ournal of Natural Products, 2001, Vol. 64, No. 8 1047
2
by direct comparison (co-TLC, mp, [R]
D
, IR, 1H NMR, 13
C
) 12.2 and 4.0 Hz, H-3R), 3.36 (1H, brs, H-21R); 13C NMR δ
16.1 (q), 16.3 (q), 18.8 (t), 19.2 (q and t), 19.4 (q), 21.5 (t), 22.2
(q), 22.3 (t), 25.8 (t), 28.03 (q), 28.08 (q), 28.18 (t), 35.8 (s),
36.1 (t), 37.7 (s), 38.18 (s), 38.24 (t), 38.40 (s), 38.9 (t), 44.9 (t),
45.2 (d), 52.8 (t and s), 56.2 (d), 57.5 (q, OMe), 65.0 (d), 75.8
(d, CHOMe), 88.5 (d, H-C-OH), 129.6 (s), 143.1 (s); EIMS
NMR, and EIMS) with an authentic sample of 2 isolated from
the cuticle.
1
3r,14r-Ep oxy-3â-m eth oxyser r a ta n -21â-ol (3): prisms;
mp 242-244 °C (MeOH-CHCl ); [R] +31 (c 0.38); IR νmax
KBr) cm 3340 (OH), 2928, 2871, 1466, 1388, and 1363 (gem
3
D
-
1
(
1
13
+
+
dimethyl), 1261, 1183, 1095, 1074, 991, and 975; H and
NMR, see Table 1; EIMS m/z (rel int) 472 (2) [M] , 456 (8) [M
-
C
m/z (rel int) 456 (45) [M] , 441 (40) [M - Me] , 438 (29) [M -
+
+
+
+
H O] , 424 (40) [M - MeOH] , 409 (15) [M - Me - MeOH] ,
2
+
+
+
+
16] , 454.3816 (8) [M - H
2
O] , 440 (5) [M - MeOH] , 421
391 (14) [M - Me - MeOH - H O] , 285 (10), 269 (9), 255
(25), 221 (85), 203 (78), 189 (100), 135 (82), 95 (60).
2
+
+
(
3
1
19) [M - 2H
2
O - Me] , 407 (1) [M - H
2
O - MeOH - Me] ,
67 (6), 319 (4), 287 (9), 269 (14), 221 (19), 203 (9), 201 (7),
P r ep a r a tion of 3 fr om 6b. A solution of MCPBA (31 mg)
89 (20), 154 (28), 136 (100), 121 (46); HREIMS m/z 472.3922
in dry CHCl
b (87 mg) in dry CHCl
temparature and allowed to stand 21 h. Workup as described
above yielded a residue, which was purified by PTLC (CHCl
MeOH, 20:1) to furnish the corrresponding 13,14-epoxyalco-
hol: 62 mg, mp 242-244 °C (MeOH-CHCl ), [R] +32 (c 0.51);
3
(5 mL) was gradually added over a solution of
+
[M] (C31
H
52
O
3
requires 472.3916).
6
3
(12 mL) under stirring at room
Acetyla tion of 3. Compound 3 (15 mg) was acetylated as
usual (Ac O-pyridine, 1:1, 2 mL) to yield a crystalline mass.
Purification by PTLC (CHCl -MeOH, 30:1) afforded 13R,14R-
epoxy-3â-methoxyserratan-21â-yl acetate (3a ), mp 228-231
2
3
-
3
3
D
-1
°
C (MeOH-CHCl
3
), 16 mg, as prisms: IR νmax (KBr) cm 1734
+
EIMS m/z 472 [M] , which was identified as 3 by direct
comparison with an authentic sample of 3.
(OAc), 1466, 1373, 1365, 1248 (OAc), 1185, 1102, 1043, 1015,
1
9
93, 985 and 946; H NMR δ 0.70 (1H, m, H-5R), 0.74 (3H, s,
Cr ysta l Da ta for Com p ou n d s 1 a n d 2. (i) Compound 1:
Me-24), 0.77 (1H, m, H-9R), 0.84 (9H, s, Me-25, Me-29, and
Me-30), 0.95 (3H, s, Me-23), 1.02 (3H, s, Me-28), 1.10 (3H, s,
Me-26), 1.36 (1H, m, H-17â), 1.56 (2H, d, J ) 4.5 Hz, H-27),
1
2
1
2
C H O , M ) 456.71, space group P212121, a ) 13.123(2) Å,
30 48 3
3
b ) 31.213(3) Å, c ) 6.129(2) Å, V ) 2510.7(8) Å , D
x
) 1.208
, M ) 470.74,
orthorhombic, space group P212121, a ) 17.421(3) Å, b )
-
3
g‚cm , Z ) 4. (ii) Compound 2:
31 50 3
C H O
.80 (1H, m, H-15â), 1.94 (1H, m, H-15R), 2.07 (3H, s, OAc),
.50 (1H, dd, J ) 15.8 and 8.3 Hz, H-12R), 2.62 (1H, dd, J )
2.2 and 4.4 Hz, H-3R), 3.35 (3H, s, OMe) and 4.65 (1H, t, J )
3
2
0.811(5) Å, c ) 7.553(1) Å, V ) 2738.3(9) Å , D ) 1.142
x
-3
1
3
g‚cm , Z ) 4. A total of 2065 independent reflection intensities
up to 2θ ) 130° were measured for compound 1 on a Rigaku
automatic four-circle diffractometer with graphite-monochro-
mated Cu KR radiation, as well as a total of 2552 independent
reflection intensities up to 2θ ) 130° for compound 2. The
structures were solved by direct methods using the SIR 92
program.8 The non-hydrogen atoms were refined by a full-
matrix least-squares method with anisotropic thermal param-
.6 Hz, H-21R); C NMR δ 16.1 (q, C-24), 16.4 (q, C-25 and
C-28), 16.6 (t, C-16), 18.3 (t, C-6), 20.6 (q, C-26), 21.2 (q, OAc),
1.6 (t, C-11), 21.7 (q, C-29), 22.2 (t, C-2), 23.9 (t, C-20), 27.5
q, C-30), 28.0 (q, C-23), 30.0 (t, C-19), 33.8 (t, C-12), 36.5 (t,
C-15), 37.1 (s, C-8), 37.3 (s, C-22), 37.6 (s, C-18), 38.4 (s, C-10),
8.5 (t, C-1), 38.9 (s, C-4), 44.8 (t, C-7), 47.4 (d, C-17), 53.8 (t,
C-27), 55.8 (d, C-5), 57.5 (q, OMe), 65.6 (s, C-14), 65.6 (d, C-9),
2
(
3
7
2.8 (s, C-13), 76.6 (t, C-21), 88.5 (d, C-3), 170.5 (s, OAc); EIMS
9
+
+
eters using the SHELXL-97 programs. Hydrogen atoms were
m/z (rel int) 514 (1) [M] , 496 (2) [M - H
CH
4
3
2
O] , 472 (4) [M -
+
+
+
calculated assuming idealized geometries but not refined. Final
cycles of least-squares refinement yielded R ) 0.061 and Rw
2
O] , 454 (6) [M - HOAc] , 436 (5) [M - HOAc - H
2
O] ,
+
+
21 (16) [436 - Me] , 407 (2) [M - HOAc - 2H
67 (5), 319 (6), 287 (7), 269 (10), 221 (7), 203 (5), 201 (5), 196
2
O - Me] ,
) 0.082 for 2065 for 1 and R ) 0.056 and R ) 0.080 for 2552
w
(
22), 189 (13), 187 (5), 136 (100), 121 (50).
Con ver sion of 3â-Meth oxyser r a t-13-en -21â-ol (6b) to
â-Meth oxyser r a t-14-en -21â-ol (6) via 3â-Meth oxyser r a t-
3-en -21â-yl Aceta te (6a ). A mixture of glacial HOAc (3 mL)
for 2 observed reflections of F > 3σ(F). All calculations were
performed using the teXan10 crystallographic software package
of Molecular Structure Corporation. Lists of atomic coordi-
nates, thermal parameters, bond lengths and angles, torsion
angles and the calculated and observed structure factors have
been deposited at the Cambridge Crystallographic Data Cen-
tre, U.K.
3
1
2 4
and c-H SO (2.3 mL) was gradually added into a solution of
compound 6 (200 mg) in HOAc (30 mL) under ice cooling, and
the mixture was kept at room temperature for 24 h. Then, the
mixture was poured into ice water, and the resulting precipi-
tate was extracted with CHCl
was neutralized with 5% NaOH solution, washed with H
and dried over Na SO . Evaporation of CHCl yielded a
crystalline mass (191 mg), which was subjected to CC on 10%
AgNO -SiO (20 g) to afford 3â-methoxyserrat-13-en-21â-yl
acetate (6a ): 131 mg, as prisms, mp 204-206 °C (MeOH-
CHCl ), from the fraction eluted with n-hexane-C (17:1),
IR νmax (KBr) cm 2963, 2934, 2895, 1735 (OAc), 1457, 1389,-
3
(30 mL × 3). The CHCl
3
extract
Ack n ow led gm en t . The authors are indebted to Mr. K.
Takamori and Mr. O. Miyazaki (National Osaka Forestry
Bureau, Osaka, J apan) and Mr. T. Yamamoto and Mr. M.
Kikuchi (National Hokkaido Forestry Bureau, Sapporo, J apan)
for collection of the plant materials. Our thanks are also due
to Dr. O. Muraoka (Faculty of Pharmaceutical Sciences, Kinki
University) for NMR measurements and Mrs. M. Fujitake of
this University for MS measurements.
2
O,
2
4
3
3
2
3
6 6
H
-
1
1
1
376, 1248 (OAc), 1184, 1105, 1094, 1042, and 934; H NMR
δ 0.74, 0.78, 0.85, and 0.87 (each 3H, s), 0.90 (6H, s), 0.96 (3H,
s), 2.08 (3H, s, OAc), 2.16 (1H, d, J ) 14.0 Hz), 2.25 (1H, dd,
J ) 14.4 and 7.5 Hz), 2.64 (1H, dd, J ) 12.2 and 4.0 Hz, H-3R),
Refer en ces a n d Notes
(
1) Tanaka, R.; Senba, H.; Minematsu, T.; Muraoka, O.; Matsunaga, S.
3
.36 (3H, s, OMe), and 4.69 (1H, t, J ) 2.7 Hz, H-21R); 13
C
Phytochemistry 1995, 38, 1467-1471.
NMR δ 16.1 (q), 16.3 (q), 18.8 (t), 19.0 (t), 19.2 (q × 2), 21.4
(2) Tanaka, R.; Ohmori, K.; Minoura, K.; Matsunaga, S. J . Nat. Prod.
1
996, 59, 237-241.
(
(
t), 21.5 (q), 21.8 (q), 22.3 (t), 23.4 (t), 27.6 (q), 28.0 (q), 28.2
t), 30.1 (t), 35.7 (s), 36.0 (t), 36.8 (s), 38.2 (t), 38.4 (s), 38.9 (s),
(
3) Tanaka, R.; Tsujimoto, K.; In, Y.; Matsunaga, S. J . Nat. Prod. 1997,
6
0, 319-322.
4
8
4.9 (t), 46.4 (d), 52.8 (t), 56.2 (d), 64.8 (d), 77.8 (d, CHOAc),
(4) Tanaka, R.; Mun, C.; Usami, Y.; Matsunaga, S. Phytochemistry 1994,
35, 1517-1522.
8.5 (d, CHOMe), 129.7 (s), 142.9 (s) and 170.9 (s, OAc); EIMS
+
(5) Tanaka, R.; Tsuboi, R; Matsunaga, S. Phytochemistry 1994, 37, 209-
(
rel int) m/z 498 (48) [M] , 483 (11) [M - HOAc - Me -
2
11.
+
+
+
MeOH] , 438 (37) [M - HOAc] , 423 (76) [M - HOAc - Me] ,
3
(
6) Tsuda, Y.; Kashiwaba, N.; Hori, T. Chem. Pharm. Bull. 1983, 31,
1073-1078.
+
91 (13) [M - HOAc - MeOH - Me] , 285 (7), 269 (6), 255
(21), 221 (54), 203 (100), 189 (83), 135 (62), 95 (48).
(7) Inubushi, Y.; Hibino, T.; Harayama, T.; Hasegawa, T.; Somanathan,
R. J . Chem. Soc., C 1971, 3109-3114.
8) Altomare, A.; Burla, M. C.; Comalli, M.; Cascarano, M.; Giacovazzo,
Treatment of acetate 6a (108 mg) in boiling 0.2 N KOH/
MeOH (32.5 mL) for 8 h and subsequent workup as usual
(
C.; Guagliardi, A.; Polidoli, G. J . Appl. Crystallogr. 1994, 27, 435.
furnished 6b: 91 mg, as needles, mp 268-270° (MeOH-
(9) Sheldrick, G. M. SHELXL-97, Program for Refinement of Crystal
Structures; University of Gotingen: Germany, 1998.
(10) teXan, Crystal Structure Analysis Package; Molecular Structure
Corporation: 1985 and 1992.
-
1
CHCl
3
), IR νmax (KBr) cm 3537 (OH), 2961, 2937, 2871, 1459,
1
1
0
1
385, 1374, 1182, 1126, 1098, 991, 964; H NMR δ 0.73, 0.76,
.83,0.85, 0.89, 0.95, and 0.97 (each 3H, s), 2.16 (1H, d, J )
4.0 Hz), 2.26 (1H, dd, J ) 14.4 and 7.5 Hz), 2.63 (1H, dd, J
NP000630E