Structural requirements of dictyopyrones isolated from Dictyostelium spp. in the regulation of Dictyostelium development and in anti-leukemic activity

Article abstract of DOI:10.1016/j.bmc.2004.04.001

Cellular slime molds are fascinating to the field of developmental biology, and have long been used as excellent model organisms for the study of various aspects of multicellular development. We have recently isolated α-pyronoids, named dictyopyrones A-D (1-4), from various species of Dictyostelium cellular slime molds, and it was shown that compound 3 may regulate Dictyostelium development. In this study, we synthesized dictyopyrones A-D (1-4) and their analogues, investigated the physiological role of the molecules in cell growth and morphogenesis in D. discoideum, and further verified their effects on human leukemia K562 cells. Nitrogen-containing compounds 22 and 37 strongly inhibited cell growth in K562 leukemia cells, indicating that these compounds may be utilized as novel lead compounds for anti-leukemic agents.

Full text of DOI:10.1016/j.bmc.2004.04.001

Bioorganic & Medicinal Chemistry 12 (2004) 3203–3214
Structural requirements of dictyopyrones isolated from
Dictyostelium spp. in the regulation of Dictyostelium development
and in anti-leukemic activity
a
Haruhisa Kikuchi, Kazunori Sasaki, Jun’ichi Sekiya, Yasuo Maeda, Aiko Amagai,
b
a
b
b
c
Yuzuru Kubohara and Yoshiteru Oshima
a,
*
a
Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-yama, Aoba-ku, Sendai 980-8578, Japan
b
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University,
Sendai 980-8578, Japan
Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
c
Received 24 February 2004; revised 31 March 2004; accepted 1 April 2004
Available online 8 May 2004
Abstract—Cellular slime molds are fascinating to the field of developmental biology, and have long been used as excellent model
organisms for the study of various aspects of multicellular development. We have recently isolated a-pyronoids, named dictyo-
pyrones A–D (1–4), from various species of Dictyostelium cellular slime molds, and it was shown that compound 3 may regulate
Dictyostelium development. In this study, we synthesized dictyopyrones A–D (1–4) and their analogues, investigated the physio-
logical role of the molecules in cell growth and morphogenesis in D. discoideum, and further verified their effects on human leukemia
K562 cells. Nitrogen-containing compounds 22 and 37 strongly inhibited cell growth in K562 leukemia cells, indicating that these
compounds may be utilized as novel lead compounds for anti-leukemic agents.
ꢀ
2004 Elsevier Ltd. All rights reserved.
1
. Introduction
DIF-1, was isolated from the fungus Chaetomium sp. as
a factor that induces erythroid differentiation in murine
5
During certain periods of their life cycles, cellular slime
molds such as Dictyostelium spp. form an animal-like
feeding stage that later undergoes transition into a
plant-like fruiting body stage. Such organisms are fas-
cinating to the field of developmental biology, and have
long been used as excellent model organisms for the
study of various aspects of multicellular development,
including signal transduction, cell motility, and cell
erythroleukemia B8 cells in vitro. Furthermore, this
factor was then found to induce the differentiation of
6
some human tumor cells. Interestingly, it has been
shown that differanisole A induces stalk cell differenti-
10
ation in vitro in D. discoideum and also that DIF-1
induces growth arrest and erythroid differentiation in
7
murine and human leukemia cells. It has also been
demonstrated that DIF-1 suppresses cell growth in rat
1
8
differentiation. Several chemical stimuli, such as
pancreatic tumor AR42J cells and human myeloid
9
leukemia HL-60 cells. These findings suggest that the
2
3
4
DIF-1, discadenine, and cAMP, have been identified
as physiologically active substances, which act during
the life cycle of Dictyostelium discoideum.
chemical structure shared by DIF-1 and differanisole A
may play an important role in cell growth and differ-
entiation in multiple species and also that there might be
some other substances having such a role in lower
eukaryotic organisms.
DIF-1 was originally identified as a factor that induces
2
stalk cell differentiation in D. discoideum. On the other
hand, differanisole A, which has structural similarity to
We have recently isolated a-pyronoids, named dictyo-
pyrones A–D (1–4), from various species of Dictyoste-
11
lium cellular slime molds. As only very small amounts
of compounds 1–4 were isolated as minor constituents
of Dictyostelium in our previous study, syntheses of
these compounds were required for further biological
Keywords: Cellular slime molds; Dictyostelium discoideum; a-pyrone;
Anti-leukemic activity.
11
*
Corresponding author. Tel.: +81-22-217-6822; fax: +81-22-217-6821;
e-mail: oshima@mail.pharm.tohoku.ac.jp
0
968-0896/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2004.04.001

3204
H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
1
1
evaluation. Therefore, dictyopyrone C (3), which bears a
saturated hydrocarbon side chain, was synthesized and
its activity on Dictyostelium development was assessed.
It was demonstrated that compound 3 inhibit cell
In our previous report, the E-double bond in the side
chain of 1 was prepared by isomerization of the terminal
olefin with a cobalt-containing complex; however, the
isomerization gave rise to a configurational mixture
(E=Z ¼ 12=1). Although it was possible to separate the
E- and Z-isomers using HPLC, this was tedious to carry
out on a preparative scale. Therefore, a modified
method for preparation of the E-olefin using the Hor-
ner–Emmons reaction was developed (Scheme 2). One
of the hydroxyl groups in 1,10-decanediol (15a) was
protected with a methoxymethyl group to produce 16a.
Oxidation of 16a by PCC gave an aldehyde that was
then reacted with ethyl diethylphosphonoacetate to
yield, as a sole product, the a,b-unsaturated ester 17a,
which bears the E-olefin. Compound 17a was reduced
with DIBAL-H to yield the allyl alcohol 18a. Reaction
of 18a with sulfur trioxide–pyridine complex, and
reduction of the resulting reaction product with LAH
12
growth and enhance morphogenesis in D. discoideum.
However, there are many aspects of the putative physio-
logical and pharmacological roles of dictyopyrone-like
molecules that are currently unknown.
In this study, we were prompted to synthesize dictyo-
pyrones A–D (1–4) and their analogues. We then
investigated the physiological roles of these molecules in
cell growth and morphogenesis in D. discoideum and
further verified their effects on human leukemia K562
cells. We show here that some dictyopyrone analogues
regulated cell growth and morphogenesis in D. discoid-
eum and also that some molecules suppressed cell
growth in K562 cells in vitro.
14
gave the dehydrated product 19a. Deprotection of 19a
afforded 20a, which was oxidized with PDC in DMF to
afford carboxylic acid 5a. Carboxylic acid 5a was used as
a starting material in Scheme 1. In a similar manner,
carboxylic acid 5b, which has the same side chain as
compound 2, was prepared from 1,12-dodecanediol
CH3
O
O
Dictyopyrone A (1):R = (CH2)8
Dictyopyrone B (2):R = (CH2)10
Dictyopyrone C (3):R = (CH2)10CH3
Dictyopyrone D (4):R = (CH2)12CH3
CH3
R
O
(
15b).
Chart 1. The structures of dictyopyrones A–D (1–4).
In Scheme 1, commercially available lauroyl chloride
6c) and myristoyl chloride (6d) were used as starting
materials to generate 3 and 4, respectively. Analogues
0–12, which bear shorter side chains, were synthesized
2
. Results and discussion
(
2
.1. Syntheses of dictyopyrones and their analogues
1
from their corresponding acid chlorides 6e–g to find
how many carbons in C-3 side chain are crucial for
biological activities. Adamantaneacetic acid (5h) was
converted into analogue 13, in which bulkiness was
added to the side chain.
Syntheses of dictyopyrones A–D (1–4) and their ana-
logues (10–14), which have modified side chains, are
11
based on our previous work (Scheme 1). Carboxylic
acids 5 or acid chlorides 6 were condensed with Mel-
13
drum’s acid to yield 5-acyl compounds 7. Alcoholysis
of 7 with (2S,4S)-2,4-pentanediol gave b-ketoesters 8.
Oxidation of 8 and subsequent intramolecular aldol
condensation allowed us to generate dictyopyrones A–D
x-Amino substituted derivative 22 was synthesized for
additional water solubility as described in Scheme 3.
(
1–4) and their analogues (10–14).
O
O
O
O
(
CH2)10CH3
i
O
OH
O
O
H3CO
(CH2)10CH3
HO
5
R
O
O
a,b,h,i
iii
OH
O
R
R
23
24
ii
O
O
O
O
Chart 2. The structures of 23 and 24.
7a-i
8a-i
Cl
R
6
c-g
O
O
O
O
iv
v
i
ii, iii
O
R
R
HO(CH2)n+2OH
5a,b
MOMO(CH ) OH
2 n+2
1
16a,b
O
a-i
O
9
1-4, 10-14
6e-9e, 10:R = CH3
CH3 6f-9f, 11:R = (CH ) CH
3
COOEt
iv
CH3
MOMO(CH2)n+1
MOMO(CH2)n+1
OH
5
a-9a, 1:R =(CH2)8
17a,b
18a,b
5
6
6
b-9b, 2:R =(CH2)10
2 4
O
6
g-9g,12:R = (CH2)6CH3
c-9c, 3: R = (CH2)10CH3
d-9d, 4: R = (CH2)12CH3
v
CH3
vii
CH3
RO(CH2)n+1
HO
(CH2)n
a,b
a: n = 8
b: n = 10
5
5
h-9h,13:R = CH2
i-9i, 14:R = (CH2)11NHBoc
19a,b: R = MOM
0a,b: R = H
vi
2
5
Scheme 1. The general procedure for the synthesis of dictyopyrones
1–4) and their analogues (10–14). Reagents and conditions: (i) Mel-
drum’s acid, EDCIÆHCl, DMAP, CH Cl , rt; (ii) Meldrum’s acid,
DMAP, CH Cl
, rt; (iii) (2S,4S)-2,4-pentanediol, toluene, 80 ꢁC; (iv)
PCC, CH Cl
, rt; (v) EtONa, EtOH, 0 ꢁC.
Scheme 2. Synthesis of 5a and 5b. Reagents and conditions: (i)
MOMCl, DIPEA, CH Cl , rt; (ii) PCC, CH Cl , rt; (iii) ethyl
diethylphosphonoacetate, NaH, benzene, 0 ꢁC; (iv) DIBAL-H,
CH Cl Æ pyridine, THF, then LAH, rt; (vi) 2M HCl,
, )20 ꢁC; (v) SO
THF, reflux; (vii) PDC, DMF, rt.
(
2
2
2
2
2
2
2
2
2
2
3
2
2

H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
3205
O
O
(Scheme 1)
i
OH OH
2R,4R)-
O
NPhth
NPhth
iv, v
i, ii
iii
O
O
HO
(CH2)11NH2
HO
ii
(CH2)11NHBoc
21
5i
(
33
34
2
,4-Pentanediol
O
O
(CH2)11NH3Cl
O
O
O
(
CH2)11NHBoc
O
O
vi
vii
R
O
R
R
O
O
1
O
O
4
22
N
H
35
O
N
H
36
O
N
H
37
O
Scheme 3. Synthesis of x-amino analogue 22. Reagents and condi-
[
R = (CH2)10CH3]
2 2
tions: (i) (Boc) O, NaOH, dioxane–H O (1:1), rt; (ii) 10% HCl–MeOH,
rt.
Scheme 5. Synthesis of 1-aza derivative 37. Reagents and conditions:
(
i) phthalimide, Ph
3
P, DEAD, THF, 0 ꢁC; (ii) PCC, CH
2
Cl
2
, rt;
(
iii) l,3-propanediol, pTsOH, benzene, reflux; (iv) H
2
NNH
2
ÆHCl,
Protection of 12-aminolauric acid (21) gave the N-Boc
derivative 5i, which was converted into compound 14
via Scheme 1. The subsequent deprotection of 14 under
acidic conditions afforded 22 as a hydrochloride salt.
The use of (2R,4R)-2,4-pentanediol instead of (2S,4S)-
MeOH, reflux; (v) 7c, toluene, 80 ꢁC; (vi) 80% AcOH, rt; (vii) EtONa,
EtOH, 0 ꢁC.
into acetal 34. Aminolysis of 6c by primary amine,
which was afforded by treatment of 34 with hydrazine,
15
2
,4-pentanediol in the same method used to synthesize 3
produced b-ketoamide 35. After deprotection of 35,
intramolecular cyclization in the presence of sodium
ethoxide yielded 37.
led to analogue 23, which is an enantiomer of 3.
Methanolysis of 7c gave acyclic b-ketoester 24, which is
equivalent to a compound lacking C-4–C-8 in the a-
pyrone moiety of 3.
2.2. Effects of dictyopyrones and their analogues on
Dictyostelium cellular slime mold
To elucidate effects of substituents on a-pyrone ring and
its ring size, syntheses of 29–32, in which the carbon
length of the side chain was fixed at 12 as in compound
The effects of dictyopyrones (1–4) and their analogues
on cell growth and morphogenesis in D. discoideum were
evaluated at concentrations of 30 and 10 lM, respec-
3
, were also carried out (Scheme 4). Reaction of 5-
lauroyl Meldrum’s acid (7c) with four commercially
available alcohols gave the b-ketoesters 25–28. Com-
pounds 25–27 were converted into a-pyrones 29–31, in
which the 4,6-dimethyl substituents in 3 were modified
to 4,6,6-trimethyl, 4-methyl, or 4,6-diisopropyl substit-
uents, respectively. Oxidation of 28 by PCC resulted in
the unexpected generation of c-hydroxy-c-lactone 32.
Table 1. The effects of dictyopyrones and their analogues on growth
and morphogenesis of D. discoideum Ax-2 cells
Compounds
Inhibitory effect
a
on growth
Effect on
morphogenesis
b
Dictyopyrone A (1)
Dictyopyrone B (2)
Dictyopyrone C (3)
Dictyopyrone D (4)
+
›
›
›
›
)
)
›
)
›
›
)
+
Compound 37, the 1-aza derivative of 3, was synthesized
using Scheme 5. Mitsunobu reaction of (2R,4R)-2,4-
pentanediol with phthalimide, and subsequent oxidation
by PCC afforded compound 33, which was converted
)
)
)
+
10
11
12
13
22
23
+
)
+
O
O
O
O
R1
R1
c
O
iii
24
29
30
31
++
+
)
R2
R2
R2
)
fl
›
fl
fl
O
O
R2
++
)
++
++
2
2
i
25: R = CH3
29: R = CH3
30: R = H
2
2
2
6: R = H
32
7
3
O
O
OH
O
O
O
OH
a
R1
i
R1 ii, iii
R1
Ax-2 (MS) cells at the mid-late exponential growth phase
6
O
5
(
5 · 10 cells/mL) were placed at 2.5 · 10 cells/mL in fresh PS medium
O
O
O
31
O
containing 30 lM of each compound. This was followed by incuba-
tion for 1 h at 22 ꢁC. ), no effects (cells were morphologically nor-
mal.); +, moderate inhibition (almost all of the cells were round in
shape.); ++, strong inhibition (almost all of the cells were lysed).
Ax-2 (MS) cells at the mid-late exponential growth phase
7c
27
R1 = (CH2)10CH3
i
O
O
b
OH
O
R1
ii
R1
6
5
2
(
5 · 10 cells/mL) were settled at 1.1 · 10 cells/cm in BSS containing
HO
O
10 lM of each compound. This was followed by incubation at 22 ꢁC.
fl, inhibition (almost all of the cells were rounded and then lysed); ),
no effects (the aggregation time of the cells was the same as for
control cells incubated in BSS with 0.05% DMSO); ›, enhancement
(cells aggregated earlier than control cells).
O
O
28
32
Scheme 4. Synthesis of 29–32. Reagents and conditions: (i) 4-hydroxy-
-methylpentan-2-one (for 25), 4-hydroxybutan-2-one (for 26),
3S,5S)-2,6-dimethylheptane-3,5-diol (for 27) or (25,35)-2,3-butanediol
for 28), toluene, 80 ꢁC; (ii) PCC, CH Cl , rt; (iii) EtONa, EtOH, 0 ꢁC.
4
c
(
(
Inhibitory effects on differentiation were noted when cells were treated
with 18 lM or higher concentrations of 24.
2
2

3206
H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
tively (Table 1). Dictyopyrones A and C (1 and 3), which
have 12 carbon side chains at C-3 with or without an E-
double bond, inhibited cell growth and enhanced cell
aggregation. Dictyopyrones B and D (2 and 4), which
bear 14 carbon side chains with or without an E-double
bond, only enhanced aggregation. These findings
demonstrate that the presence of an E-olefin in the C-3
side chain should not be important for the biological
activity of dictyopyrones in Dictyostelium. Evaluation of
the shorter C-3 hydrocarbon side chain analogues indi-
cated that the activity of analogue 12, which contains an
eight carbon side chain, was equivalent to the activity of
2.3. Effects of dictyopyrone analogues on cell growth in
human leukemia K562 cells
In order to assess whether dictyopyrones A–D (1–4) and
their analogues have therapeutic potential in the treat-
ment of leukemia, we examined and compared the
effects of structurally related analogues on cell growth in
human leukemia K562 cells. As shown in Figure 1A,
dictyopyrones A and C (1 and 3) suppressed cell growth
in a similar manner; at 60 lM these compounds sup-
pressed cell growth by about 60%. At concentrations of
up to 80 lM, compounds 10 and 12 did not affect cell
growth, suggesting that a 12 carbon side chain is
required for inhibition of growth in these cells, even
though eight carbon or longer side chains were sufficient
for inhibition of Dictyostelium cell growth.
3
, while compounds 10 and 11, which have two and six
carbon side chains, respectively, had no activity on
either cell growth or morphogenesis. Furthermore, we
found that a hydrocarbon side chain containing eight or
more carbon atoms was critical for enhancement of cell
aggregation, while a side chain containing between 8
and 12 carbon atoms was required for the inhibition of
cell growth. Analogue 13, which contains a bulky ada-
mantyl group in place of a 12 carbon linear chain,
retained an inhibitory effect on cell growth, but showed
no effect on morphogenesis. In contrast, compound 22
only enhanced morphogenesis. b-Ketoester 24 was a
potent inhibitor of cell growth but had no effect on
morphogenesis. This suggests that the a-pyrone ring is
critical for the effects of these compounds on morpho-
genesis.
Compounds 13, 23, and 31 suppressed cell growth in a
dose dependent manner, as shown in Figure 1B. The
effect of 24 was weaker than the effects of 1 and 3,
indicating that the structures of both the a-pyrone ring
and the hydrocarbon side chain are important for the
inhibition of cell growth.
The nitrogen-containing compounds 22 and 37 were
more potent inhibitors of cell growth (Fig. 1C), while
compound 32 was very toxic; most cells died in the
presence of greater than 2 lM 32 (Fig. 1D).
The activity of analogue 23 was identical to the activity of
3
is not important for activity. However, the requirements
of the C-4 and C-6 methyl groups for biological activity
were not distinctly accounted for in the comparative
studies of 3 and its analogues 29, 30, and 31.
, suggesting that the stereochemistry at the C-6 position
3
. Conclusion
In this study, we synthesized dictyopyrones A–D (1–4)
and their analogues, and assessed their physiological
and pharmacological activities. Since dictyopyrone A
(
3
1), C (3), and the synthesized analogues (13, 23, 32, and
7) inhibited cell growth in both D. discoideum and
Aza-analogue 37 and hydroxylactone 32 strongly
inhibited both cell growth and morphogenesis of D.
discoideum cells.
K562 cells, there may be similar mechanisms of cell
growth in Dictyostelium and tumor cells, although sev-
eral compounds acted differently on the two types of
cell.
In addition, nitrogen-containing compounds 22 and 37
strongly inhibited cell growth in K562 leukemia cells,
indicating that these compounds may be utilized as
novel lead compounds for anti-leukemic agents. It will
be necessary to examine the in vitro and in vivo effects of
dictyopyrone analogues on many other tumor cell types
in order to develop more potent anti-tumor agents in the
near future.
4. Experimental section
4
.1. General methods
Analytical TLC was performed on silica gel 60 F254
Merck) and RP-18 F254s (Merck). Column chroma-
(
tography was carried out on silica gel 60 (70–230 mesh,
Merck), and Cosmosil 140C18-OPN (Nacalai Tesque,
Kyoto, Japan). NMR spectra were recorded on JEOL
Figure 1. The effects of dictyopyrones and their analogues on the
growth of human leukemia K562 cells.

H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
3207
1
3
JNM GX-500, AL-400, and Varian Gemini 2000. Mass
spectra were measured on JEOL JMS DX-303, AX-500,
and AX-700.
dqd, J ¼ 9:6, 6.3, 3.0 Hz); C NMR (75 MHz, CDCl
3
) d
20.5, 23.0, 23.3, 26.6 (3C), 28.2, 28.3, 28.8, 29.2, 29.3,
29.3, 29.9, 35.0, 40.5, 43.1, 45.6, 49.4, 63.5, 69.5, 78.9,
þ
1
56.1, 167.9, 203.4; HREIMS m=z 370.2651 [M-tBuO]
(370.2672 calcd for C20H36NO ).
5
4
.1.1. (1S,3S)-3-Hydroxy-1-methylbutyl (E)-3-oxotetra-
dec-12-enoate (8a). To a solution of 5a (286 mg,
.44 mmol) in CH Cl (8 mL) was added 1-(3-dimeth-
ylaminopropyl)-3-ethylcarbodiimide hydrochloride
EDCIÆHCl) (459 mg, 2.39 mmol), Meldrum’s acid
396 mg, 2.75 mmol), and DMAP (35.6 mg, 0.29 mmol)
at 0 ꢁC. After being stirred for 2 h, the mixture was
poured into 1 M hydrochloric acid and extracted with
diethyl ether three times. The organic layer was washed
with brine, dried over anhydrous sodium sulfate, and
evaporated to give crude 5-acyl Meldrum’s acid 7a. This
crude and (2S,4S)-2,4-pentanediol (249 mg, 2.39 mmol)
were dissolved in toluene (5 mL). After being heated at
1
2
2
4.1.2. (1S,3S)-3-Hydroxy-1-methylbutyl 12-oxotetrade-
canoate (8c). To a solution of lauroyl chloride
(219 mg, 1.00 mmol) in CH Cl (3 mL) was added Mel-
2 2
(
(
drum’s acid (159 mg, 1.10 mmol) and pyridine (162 lL,
2.00 mmol) at 0 ꢁC. After being stirred for 3 h, the
mixture was poured into 1 M hydrochloric acid and
extracted with diethyl ether three times. The organic
layer was washed with brine, dried over anhydrous so-
dium sulfate, and evaporated to give crude 5-acyl
Meldrum’s acid 7c. This crude and (2S,4S)-2,4-pen-
tanediol (156 mg, 1.10 mmol) were dissolved in toluene
(3 mL). After being heated at 80 ꢁC for 3 h, this mixture
was evaporated. The residue was chromatographed over
silica gel eluted by n-hexane–ethyl acetate (4:1) to give
80 ꢁC for 3 h, this mixture was evaporated. The residue
was chromatographed over silica gel eluted by n-hex-
ane–ethyl acetate (4:1) to give 8a (195 mg, 42% from 5a).
8
1
1
a: Colorless oil; H NMR (300 MHz, CDCl ) d 1.19
8c (226 mg, 69% from 5c). 8c: Colorless powder; H
NMR (500 MHz, CDCl
3
(
3H, d, J ¼ 6:3 Hz), 1.24–1.30 (10H, m), 1.28 (3H, d,
J ¼ 6:3 Hz), 1.53–1.72 (4H, m), 1.64 (3H, dq, J ¼ 3:3,
.4 Hz), 1.96 (2H, m), 2.52 (2H, t, J ¼ 7:4 Hz), 3.46 (2H,
3
) d 0.88 (3H, t, J ¼ 6:6 Hz),
1.18 (3H, d, J ¼ 7:6 Hz), 1.26–1.29 (16H, m), 1.28 (3H,
d, J ¼ 3:1 Hz), 1.55–1.63 (2H, m), 1.58 (1H, ddd,
J ¼ 14:5, 9.8, 3.1 Hz), 1.67 (1H, ddd, J ¼ 14:5, 9.9,
2.9 Hz), 2.51 (2H, t, J ¼ 7:5 Hz), 3.39 (2H, s), 3.83 (1H,
1
s), 3.83 (1H, m), 5.22 (1H, dqd, J ¼ 9:6, 6.3, 3.3 Hz),
13
5
2
4
3
.35–5.48 (2H, m); C NMR (100 MHz, CDCl ) d 18.0,
13
0.7, 23.3, 23.5, 29.0, 29.1, 29.3, 29.3, 29.6, 32.6, 43.2,
5.7, 49.5, 63.5, 69.6, 124.5, 131.5, 167.6, 203.0;
m), 5.21 (1H, dqd, J ¼ 9:9, 6.3, 3.1 Hz); C NMR
(125 MHz, CDCl ) d 14.0, 20.5, 22.6, 23.1, 23.4, 28.9,
3
þ
HREIMS m=z 326.2422 [M] (326.2455 calcd for
29.2, 29.3, 29.3, 29.4, 29.4, 31.8, 43.1, 45.6, 49.4, 63.4,
þ
C
19
H
34
O
4
).
69.5, 167.6, 203.1; HREIMS m=z 329.2686 [M+H]
(
329.2690 calcd for C H O ).
19 37 4
In the similar procedure, compounds 8b (yield 50%), 8h
14%), and 8i (35%) were prepared from the corre-
sponding carboxylic acid (5b, 5h, and 5i), respectively.
1S,3S)-3-Hydroxy-1-methylbutyl (E)-3-oxohexadec-14-
(
In the similar procedure, compounds 8d (yield 63%), 8e
(42%), 8f (59%), and 8g (49%) were prepared from the
corresponding carboxylic acid (5d, 5e, 5f, and 5g),
respectively. (1S,3S)-3-Hydroxy-1-methylbutyl-3-oxo-
(
1
3
enoate (8b): Colorless oil; H NMR (300 MHz, CDCl )
1
d 1.19 (3H, d, J ¼ 6:3 Hz), 1.24–1.30 (14H, m), 1.28 (3H,
hexadecanoate (8d): Colorless powder; H NMR
d, J ¼ 6:3 Hz), 1.53–1.72 (4H, m), 1.64 (3H, dq J ¼ 3:3,
(300 MHz, CDCl ) d 0.88 (3H, t, J ¼ 6:7 Hz), 1.19 (3H,
3
1
.4 Hz), 1.95 (2H, m), 2.52 (2H, t, J ¼ 7:4 Hz), 3.46 (2H,
d, J ¼ 6:3 Hz), 1.24–1.28 (20H, m), 1.29 (3H, d,
J ¼ 6:6 Hz), 1.55–1.63 (2H, m), 1.58 (1H, ddd, J ¼ 14:6,
9.6, 3.0 Hz), 1.68 (1H, ddd, J ¼ 14:6, 9.6, 3.0 Hz), 2.53
(2H, t, J ¼ 7:3 Hz), 3.47 (2H, s), 3.84 (1H, dqd, J ¼ 9:8,
s), 3.83 (1H, m), 5.23 (1H, dqd, J ¼ 9:6, 6.3, 3.3 Hz),
13
5
2
3
2
.39–5.48 (2H, m); C NMR (100 MHz, CDCl ) d 17.9,
3
0.6, 23.2, 23.5, 29.0, 29.2, 29.3, 29.4, 29.5, 29.5, 29.6,
2.6, 43.2, 45.7, 49.5, 63.4, 69.5, 124.4, 131.5, 167.6,
03.0; HREIMS m=z 354.2798 [M] (354.2770 calcd for
1
3
6.3, 3.0 Hz), 5.22 (1H, dqd, J ¼ 9:6, 6.6, 3.0 Hz);
C
þ
NMR (75 MHz, CDCl ) d 13.9, 20.4, 22.5, 23.0, 23.3,
3
C
mantyl)-3-oxobutanoate (8h): Colorless powder;
21
H
38
O
4
). (1S,3S)-3-Hydroxy-1-methylbutyl 4-(l-ada-
1
26.1, 28.9, 29.2, 29.3, 29.5, 31.8, 43.1, 45.6, 49.4, 63.4,
þ
H
69.5, 167.9, 203.4; HREIMS m=z 356.2925 [M]
NMR (300 MHz, CDCl ) d 1.19 (3H, d, J ¼ 6:0 Hz),
(356.2924 calcd for C H O ). (1S,3S)-3-Hydroxy-1-
1
3
21 40
4
1
.24–1.30 (14H, m), 1.29 (3H, d, J ¼ 6:3 Hz), 1.97 (3H,
methylbutyl 3-oxobutanoate (8e): Colorless oil;
NMR (500 MHz, CDCl
H
m), 2.26 (2H, s), 3.45 (2H, s), 3.85 (1H, dqd, J ¼ 9:1, 6.0,
3
) d 1.19 (3H, t, J ¼ 6:3 Hz),
1
3
3
(
.0 Hz), 5.22 (1H, dqd, J ¼ 9:9, 6.3, 3.1 Hz); C NMR
1.29 (3H, d, J ¼ 6:3 Hz), 1.58 (1H, ddd, J ¼ 14:5, 9.8,
3.1 Hz), 1.68 (1H, ddd, J ¼ 14:5, 9.7, 3.0 Hz), 2.27 (3H,
s), 3.48 (2H, s), 3.83 (1H, dqd, J ¼ 9:7, 6.3, 3.0 Hz), 5.21
75 MHz, CDCl ) d 20.5, 23.0,28.4 (3C), 33.6, 36.5 (3C),
3
4
2.2 (3C), 45.6, 49.9, 56.1, 63.4, 69.5, 167.8, 202.9;
þ
13
HREIMS m=z 322.2127 [M] (322.2142 calcd for
C H O ). (1S,3S)-3-Hydroxy-1-methylbutyl 14-tert-
butoxycarbonylamino-3-oxotetradecanoate (8i): Color-
(1H, dqd, J ¼ 9:8, 6.3, 3.1 Hz); C NMR (125 MHz,
CDCl ) d 20.5, 23.2, 30.1, 45.5, 50.2, 63.4, 69.6, 167.4,
19
30
4
3
þ
200.8; HREIMS m=z 188.1059 [M] (188.1048 calcd for
1
less powder; H NMR (300 MHz, CDCl
3
) d 1.19 (3H, d,
9 16 4
C H O ). (1S,3S)-3-Hydroxy-1-methylbutyl 3-oxooct-
1
J ¼ 6:0 Hz), 1.24–1.26 (14H, m), 1.29 (3H, d,
anoate (8f): Colorless oil; H NMR (300 MHz, CDCl ) d
3
J ¼ 6:3 Hz), 1.39–1.51 (2H, m), 1.44 (9H, s), 1.52–1.65
0.89 (3H, t, J ¼ 6:9 Hz), 1.19 (3H, d, J ¼ 6:3 Hz), 1.24–
1.37 (4H, m), 1.28 (3H, d, J ¼ 6:3 Hz), 1.54–1.72 (4H,
m), 2.53 (2H, t, J ¼ 7:4 Hz), 3.47 (2H, s), 3.84 (1H,
dqd, J ¼ 9:5, 6.3, 3.3 Hz), 5.23 (1H, dqd, J ¼ 9:6, 6.3,
(
2H, m), 1.58 (1H, ddd, J ¼ 14:4, 9.6, 3.0 Hz), 1.68 (1H,
0
ddd, J ¼ 14:4, 9.8, 3.0 Hz, H-2 b), 2.52 (2H, t,
J ¼ 7:4 Hz, H-4), 3.08 (2H, q, J ¼ 6:6 Hz, H-14), 3.46
13
(
2H, s), 3.84 (1H, dqd, J ¼ 9:8, 6.0, 3.0 Hz), 5.23 (1H,
3
3.3 Hz); C NMR (100 MHz, CDCl ) d 13.8, 20.5, 20.5,

3208
H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
1
3
2
3.1, 23.2, 31.0, 43.0, 45.5, 49.4, 63.3, 69.5, 167.4, 203.0;
þ
6.3 Hz), 3.39 (2H, s), 5.35 (1H, m); C NMR (75 MHz,
CDCl ) d 14.0, 19.7, 22.5, 23.3, 28.9, 29.2, 29.2, 29.3, 29.3
(2C), 29.4, 29.5, 30.3, 31.8, 43.4, 49.1, 49.3, 68.0, 166.6,
HREIMS m=z 245.1760 [M+H] (245.1751 calcd for
C H O ). (1S,3S)-3-Hydroxy-1-methylbutyl 3-oxode-
3
13
25
4
1
þ
canoate (8g): Colorless oil; H NMR (300 MHz, CDCl
d 0.88 (3H, t, J ¼ 6:0 Hz), 1.16 (3H, d, J ¼ 6:3 Hz),
.21–1.28 (8H, m), 1.28 (3H, d, J ¼ 6:3 Hz), 1.52–1.71
4H, m), 2.53 (2H, t, J ¼ 7:3 Hz), 3.46 (2H, s), 3.84 (1H,
3
)
203.2, 205.4; HREIMS m=z 354.2733 [M] (354.2768
calcd for C21
butanoate (9e): Colorless oil; H NMR (500 MHz,
CDCl
38 4
H O ). (S)-1-Methyl-3-oxobutyl 3-oxo-
1
1
(
3
) d 1.30 (3H, t, J ¼ 6:3 Hz), 2.16 (3H, s), 2.25 (3H,
dqd, J ¼ 9:5; 6:3; 3:2 Hz), 5.22 (1H, dqd, J ¼ 9:7, 6.3,
s), 2.60 (1H, dd, J ¼ 16:8, 5.6 Hz), 2.83 (1H, dd, J ¼ 16:8,
13
13
3
2
1
.4 Hz); C NMR (75 MHz, CDCl ) d 13.9, 20.5, 22.4,
7.2 Hz), 3.40 (2H, s), 5.35 (1H, m); C NMR (125 MHz,
) d 19.8, 30.0, 30.3, 49.1, 50.2, 69.6, 166.3, 200.4,
3
3.1, 23.3, 26.1, 28.8, 31.5, 43.1, 45.6, 49.4, 63.4, 69.6,
þ
CDCl
205.1; HREIMS m=z 186.0891 [M] (186.0891 calcd for
3
þ
67.9, 203.4; HREIMS m=z 272.1998 [M] (272.1986
calcd for C H O ).
C H O ). (S)-1-Methyl-3-oxobutyl 3-oxooctanoate (9f):
9
15
28
4
14
4
1
Colorless oil; H NMR (300 MHz, CDCl ) d 0.89 (3H, t,
3
J ¼ 6:9 Hz), 1.22–1.36 (4H, m), 1.30 (3H, d, J ¼ 6:3 Hz),
1.59 (2H, quint, J ¼ 7:4 Hz), 2.16 (3H, s), 2.52 (2H, t,
J ¼ 7:4 Hz), 2.59 (1H, dd, J ¼ 16:8, 5.8 Hz), 2.84 (1H,
4
.1.3. (S)-1-Methyl-3-oxobutyl (E)-3-oxotetradec-12-eno-
ate (9a). PCC (647 mg, 1.70 mmol) was added to a
solution of 8a (165 mg, 0.51 mmol) in CH Cl (3 mL) at
13
2
2
dd, J ¼ 16:8, 7.1 Hz), 3.40 (2H, s), 5.36 (1H, m);
C
room temperature. After being stirred for 12 h, the
mixture was filtered through a Celite pad. The filter cake
was washed with diethyl ether, and the filtrate was
concentrated. The residue was chromatographed over
3
NMR (100 MHz, CDCl ) d 13.9, 19.8, 19.9, 23.1, 30.4,
31.1, 42.9, 49.1, 49.4, 68.0, 166.3, 202.7, 204.9; HREIMS
þ
m=z 242.1490 [M] (242.1517 calcd for C13
Methyl-3-oxobutyl 3-oxodecanoate (9g): Colorless oil;
22 4
H O ). (S)-1-
1
silica gel eluted by n-hexane–ethyl acetate (9:1) to give
1
H NMR (300 MHz, CDCl ) d 0.89 (3H, t, J ¼ 6:9 Hz),
3
9
a (137 mg, 83%). 9a: Colorless amorphous solid; H
1.22–1.36 (8H, m), 1.31 (3H, d, J ¼ 6:2 Hz), 1.59 (2H,
quint, J ¼ 7:4 Hz), 2.17 (3H, s), 2.52 (2H, t, J ¼ 7:4 Hz),
2.60 (1H, dd, J ¼ 16:8, 5.9 Hz), 2.84 (1H, dd, J ¼ 16:8,
NMR (300 MHz, CDCl ) d 1.24–1.27 (10H, m), 1.30
3
(
(
(
(
5
1
4
3H, d, J ¼ 6:4 Hz), 1.58 (2H, quint, J ¼ 7:3 Hz), 1.64
13
3H, dq, J ¼ 3:0, 1.4 Hz), 1.96 (2H, m), 2.16 (3H, s), 2.51
2H, t, J ¼ 7:3 Hz), 2.59 (1H, dd, J ¼ 16:8, 5.8 Hz), 2.83
1H, dd, J ¼ 16:8, 6.9 Hz), 3.39 (2H, s), 5.34 (1H, m),
7.1 Hz), 3.40 (2H, s), 5.36 (1H, m); C NMR (100 MHz,
3
CDCl ) d 13.9, 19.8, 19.9, 23.1, 26.1, 28.8, 30.4, 31.1, 42.9,
49.1, 49.4, 68.0, 166.3, 202.7, 204.9; HREIMS m=z
13
þ
.39–5.48 (2H, m); C NMR (100 MHz, CDCl ) d 18.0,
270.1852 [M] (270.1831 calcd for C H O ). (S)-1-
Methyl-3-oxobutyl
3
15 26
4
9.9, 23.5, 29.0, 29.1, 29.3, 29.3, 29.6, 30.4, 32.6, 43.0,
9.2, 49.4, 68.1, 124.5, 131.5, 166.3, 202.7, 205.0;
4-(l-adamantyl)-3-oxobutanoate
1
(9h): Colorless oil; H NMR (300 MHz, CDCl ) d 1.30
3
þ
HREIMS m=z 324.2289 [M] (324.2300 calcd for
C H O ).
19 32 4
(3H, d, J ¼ 3:3 Hz), 1.64 (12H, m), 1.96 (3H, m), 2.17
(3H, s), 2.25 (2H, s), 2.59 (1H, dd, J ¼ 16:7, 6.0 Hz), 2.85
1
3
(
1H, dd, J ¼ 16:7, 6.9 Hz), 3.37 (2H, s), 5.35 (1H, m).
C
In the similar procedure, compounds 9b–i (yield: 75%
9b), 80% (9c), 82% (9d), 52% (9e), 77% (9f), 79% (9g),
0% (9h), and 54% (9i)) were prepared from 8b–i,
respectively. (S)-1-Methyl-3-oxobutyl (E)-3-oxohexadec-
NMR (75 MHz, CDCl ) d 19.8, 28.4 (3C), 30.3, 33.6, 36.6
3
(
7
(3C), 42.2 (3C), 49.2, 52.0, 55.9, 68.0, 166.6, 202.5, 205.5;
þ
HREIMS m=z 320.1994 [M] (320.1986 calcd for
C
19
H
28
O
bonylamino-3-oxotetradecanoate (9i): Colorless powder;
4
). (S)-1-Methyl-3-oxobutyl 14-tert-butoxycar-
1
1
4-enoate (9b): Colorless amorphous solid; H NMR
1
(
300 MHz, CDCl ) d 1.24–1.28 (14H, m), 1.30 (3H, d,
3
3
H NMR (300 MHz, CDCl ) d 1.21–1.34 (14H, m), 1.30
J ¼ 6:6 Hz), 1.58 (2H, quint, J ¼ 7:1 Hz), 1.64 (3H, dq,
J ¼ 3:3, 1.4 Hz), 1.95 (2H, m), 2.16 (3H, s), 2.51 (2H, t,
J ¼ 7:1 Hz), 2.59 (1H, dd, J ¼ 16:8, 5.8 Hz), 2.84 (1H,
dd, J ¼ 16:8, 7.1 Hz), 3.39 (2H, s), 5.36 (1H, m), 5.39–
(3H, d, J ¼ 6:3 Hz), 1.40–1.50 (2H, m), 1.44 (9H, s), 1.55–
1.61 (2H, m), 2.16 (3H, s), 2.51 (2H, t, J ¼ 7:1 Hz), 2.59
(1H, dd, J ¼ 16:8, 5.8 Hz), 2.84 (1H, dd, J ¼ 16:8,
7.1 Hz), 3.10 (2H, q, J ¼ 6:9 Hz), 3.39 (2H, s), 5.35 (1H,
13
13
5
2
4
.48 (2H, m); C NMR (100 MHz, CDCl ) d 17.9, 20.0,
m); C NMR (75 MHz, CDCl ) d 19.8, 23.3, 26.7 (3C),
3
3
3.4, 29.0, 29.1, 29.3, 29.4, 29.4, 29.5, 29.6, 30.4, 32.6,
3.0, 49.1, 49.4, 68.0, 124.4, 131.5, 166.3, 202.7, 205.0;
28.3, 28.4, 28.9, 29.3, 29.3, 29.4, 29.9, 30.0, 36.6, 40.5,
42.9, 49.3, 49.4, 68.0, 78.6, 156.1, 166.7, 203.2, 205.4;
þ
þ
HREIMS m=z 352.2623 [M] (352.2612 calcd for
HREIMS m=z 341.2264 [M)tBuO+H] (341.2202 calcd
C
21
H
36
O
4
). (S)-1-Methyl-3-oxobutyl 3-oxotetradecano-
1
for C18H31NO ).
5
3
ate (9c): Colorless powder; H NMR (500 MHz, CDCl )
d 0.88 (3H, t, J ¼ 6:9 Hz), 1.25–1.30 (16H, m), 1.30 (3H,
d, J ¼ 6:3 Hz), 1.58 (2H, quint, J ¼ 7:2 Hz), 2.16 (3H, s),
4.1.4.
(S)-3-[(E)-Dodec-12-enoyl]-5,6-dihydro-4,6-di-
2
.51 (2H, t, J ¼ 7:2 Hz), 2.59 (1H, dd, J ¼ 16:9, 5.8 Hz),
.83 (1H, dd, J ¼ 16:9, 7.1 Hz), 3.39 (2H, s), 5.34 (1H, m);
methyl-2H-pyran-2-one (dictyopyrone A) (1). Com-
pound 9a (115 mg, 0.36 mmol) dissolved in ethanol
(2 mL) was treated with sodium ethoxide (27.2 mg,
0.40 mmol) at room temperature for 8 h. The mixture was
poured into 0.5 M hydrochloric acid and extracted with
diethyl ether three times. The organic layer was washed
with brine, dried over anhydrous sodium sulfate, and
evaporated. The residue was chromatographed over sil-
ica gel eluted by n-hexane–ethyl acetate (4:1) to give 1
2
13
C NMR (125 MHz, CDCl ) d 14.0, 19.8, 22.6, 23.4,
3
2
4
8.9, 29.2, 29.3, 29.4, 29.4, 29.5, 30.3, 31.8, 42.9, 49.0,
9.3, 68.0, 166.4, 202.8, 205.0; HREIMS m=z 326.2502
þ
[M] (326.2455 calcd for C H O ). (S)-1-Methyl-3-ox-
1
obutyl 3-oxohexadecanoate (9d): Colorless oil; H NMR
19
34
4
(
300 MHz, CDCl
3
) d 0.88 (3H, t, J ¼ 6:6 Hz), 1.24–1.26
(
20H, m), 1.30 (3H, d, J ¼ 6:3 Hz), 1.58 (2H, quint,
28
J ¼ 7:4 Hz), 2.16 (3H, s), 2.51 (2H, t, J ¼ 7:4 Hz), 2.59
1H, dd, J ¼ 17:1, 5.8 Hz), 2.84 (1H, dd, J ¼ 17:1,
(68.0 mg, 62%). 1: Colorless amorphous solid; ½aꢀ + 54:1
D
1
(
(c 1.23, CHCl
3
); H NMR (500 MHz, CDCl
3
) d 1.20–1.35

H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
3209
(
10H, m), 1.43 (3H, d, J ¼ 6:3 Hz), 1.61 (2H, quint,
(4H, m), 1.43 (3H, d, J ¼ 6:3 Hz), 1.62 (2H, quint,
J ¼ 7:4 Hz), 2.01 (3H, d, J ¼ 0:8 Hz), 2.34 (1H, dd,
J ¼ 18:0, 3.8 Hz), 2.45 (1H, ddd, J ¼ 18:0, 11.6, 0.8 Hz),
2.71 (1H, dt, J ¼ 17:2, 7.4 Hz), 2.75 (1H, dt, J ¼ 17:2,
J ¼ 7:3 Hz), 1.65 (3H, dq, J ¼ 3:5, 1.2 Hz), 1.95 (2H, m),
2
2
.01 (3H, d, J ¼ 0:8 Hz), 2.31 (1H, dd, J ¼ 18:0, 3.7 Hz),
.44 (1H, ddd, J ¼ 18:0, 11.6, 0.8 Hz), 2.71 (1H, dt,
13
J ¼ 17:2, 7.3 Hz), 2.75 (1H, dt, J ¼ 17:2, 7.3 Hz), 4.54
7.4 Hz), 4.55 (1H, dqd, J ¼ 11:6, 6.3, 3.8 Hz); C NMR
13
(
NMR (125 MHz, CDCl
1H, dqd, J ¼ 11:6, 6.3,3.7 Hz), 5.35–5.45 (2H, m);
C
(150 MHz, CDCl ) d 13.9, 20.5, 20.9, 22.5, 23.4, 31.3,
3
3
) d 17.8, 20.4, 20.8, 23.7, 29.0,
9.1, 29.3, 29.3, 29.5, 32.5, 37.7, 43.4, 73.0, 124.5, 130.0,
37.7, 43.4, 73.1, 129.9, 156.0, 163.0, 203.2; HREIMS m=z
þ
2
1
(
224.1412 [M] (224.1411 calcd for C13
H
20
O
3
). (S)-3-Oc-
(12):
3
); H NMR
þ
31.6, 156.0, 163.1, 203.4; HREIMS m=z 306.2175 [M]
tanoyl-5,6-dihydro-4,6-dimethyl-2H-pyran-2-one
28
D
1
306.2193 calcd for C19
H
30
O
3
).
Colorless oil; ½aꢀ + 98:0 (c 1.00, CHCl
(
600 MHz, CDCl
3
) d 0.84 (3H, t, J ¼ 6:7 Hz), 1.18–1.35
In the similar procedure, compounds 2–4 and 10–14
yield: 58% (2), 48% (3), 72% (4), 60% (10), 41% (11),
(8H, m), 1.39 (2H, d, J ¼ 6:3 Hz), 1.58 (2H, quint,
J ¼ 7:4 Hz), 2.02 (3H, s), 2.28 (1H, dd, J ¼ 18:0, 4.0 Hz),
2.42 (1H, ddd, J ¼ 18:1, 11.4 Hz), 2.71 (1H, dt, J ¼ 17:1,
7.4 Hz), 2.74 (1H, dt, J ¼ 17:1, 7.4 Hz), 4.55 (1H, dqd,
(
4
9
0% (12), 16% (13) and 68% (14)) were prepared from
b–i, respectively. (S)-3-[(E)-Tetradec-14-enoyl]-5,6-
13
dihydro-4,6-dimethyl-2H]-pyran-2-one 28 (dictyopyrone
J ¼ 11:4, 6.3, 4.0 Hz); C NMR (150 MHz, CDCl ) d
3
B) (2): Colorless amorphous solid; ½aꢀ + 74:5 (c 1.11,
13.9, 20.3, 20.7, 22.4, 23.6, 28.9, 29.0, 31.5, 37.6, 43.3,
73.0, 130.1, 156.2, 163.3, 203.6; HREIMS m=z 252.1706
D
1
CHCl
3
); H NMR (500 MHz, CDCl
3
) d 1.20–1.35 (14H,
þ
m), 1.44 (3H, d, J ¼ 6:3 Hz), 1.61 (2H, quint,
[M] (252.1724 calcd for C H O ). (S)-3-Adaman-
24
15
3
J ¼ 7:4 Hz), 1.64 (3H, dq, J ¼ 3:7, 1.2 Hz), 1.95 (2H, m),
taneacetyl-5,6-dihydro-4,6-dirnethyl-2Hf-pyran-2-one
1
2
8
2
2
.01 (3H, d, J ¼ 0:8 Hz), 2.31 (1H, dd, J ¼ 18:0, 3.7 Hz),
.44 (1H, ddd, J ¼ 18:0, 11.6, 0.8 Hz), 2.71 (1H, dt,
(13): Colorless powder; ½aꢀ + 60:0 (c 1.02, CHCl
3
); H
D
NMR (500 MHz, CDCl ) d 1.43 (3H, d, J ¼ 6:3 Hz),
3
J ¼ 17:2, 7.4 Hz), 2.75 (1H, dt, J ¼ 17:2, 7.4 Hz), 4.55
1.62–1.71 (12H, m), 1.95 (3H, m), 2.06 (3H, s), 2.29 (1H,
dd, J ¼ 17:9, 3.6 Hz), 2.43 (1H, dd, J ¼ 17:9, 15.1 Hz),
2.45 (1H, d, J ¼ 15:1 Hz), 2.65 (1H, d, J ¼ 15:1 Hz), 4.53
13
(
1H, dqd, J ¼ 11:6, 6.3,3.7 Hz), 5.36–5.45 (2H, m);
C
NMR (125 MHz, CDCl ) d 17.8, 20.4, 20.8, 23.7, 29.1,
3
13
2
1
3
9.3, 29.4, 29.4, 29.4, 29.5, 29.6, 32.5, 37.7, 43.4, 73.0,
24.4, 130.0, 131.6, 156.0, 163.1, 203.4; HREIMS m=z
(1H, dqd, J ¼ 15:1, 6.3, 3.6 Hz); C NMR (75 MHz,
3
CDCl ) d 20.4, 20.9, 28.6 (3C), 34.0, 36.8 (3C), 38.0, 42.5
þ
34.2494 [M] (334.2506 calcd for C21
H
34
O
3
). (S)-3-
(3C), 56.7, 73.0, 131.4, 155.7, 163.4, 202.4; HREIMS m=z
þ
Dodecanoyl-5,6-dihydro-4,6-dimethyl-2-pyran-2-one
(
+
302.1888 [M] (302.0179 calcd for C H O ). (S)-3-(12-
tert-Butoxycarbonylaminododecanoyl)-5,6-dihydro-4,6-
19
26
3
2
D
) d
5
dictyopyrone C) (3): Colorless amorphous solid; ½aꢀ
1
1
76.8 (c 1.06, CHCl
3
); H NMR (500 MHz, CDCl
3
dimethyl-2Hf-pyran-2-one (14): Colorless powder; H
NMR (300 MHz, CDCl ) d 1.26 (14H, m), 1.40–1.50
0
.89 (3H, t, J ¼ 6:9 Hz), 1.20–1.35 (16H, m), 1.43 (3H, d,
3
J ¼ 6:3 Hz), 1.61 (2H, quint, J ¼ 7:3 Hz), 2.01 (3H, d,
J ¼ 1:0), 2.33 (1H, dd, J ¼ 18:0, 3.7 Hz), 2.44 (1H, ddd,
J ¼ 18:0, 11.6, 1.0 Hz), 2.70 (1H, dt, J ¼ 17:1, 7.3 Hz),
(2H, m), 1.44 (9H, s), 1.44 (3H, d, J ¼ 6:3 Hz), 1.61 (2H,
quint, J ¼ 7:1 Hz), 2.01 (3H, d, J ¼ 0:8 Hz), 2.31 (1H,
dd, J ¼ 17:9, 3.8 Hz), 2.45 (1H, ddd, J ¼ 17:9, 11.4,
0.8 Hz), 2.73 (1H, dt, J ¼ 17:2, 7.1 Hz), 2.76 (1H, dt,
J ¼ 17:2, 7.4 Hz), 3.10 (2H, q, J ¼ 6:5 Hz), 4.55 (1H,
2
6
2
3
3
.74 (1H, dt, J ¼ 17:1, 7.3 Hz), 4.55 (1H, dqd, J ¼ 11:5,
13
.3, 3.7 Hz); C NMR (125 MHz, CDCl ) d 13.9, 20.3,
3
1
3
0.6, 22.5, 23.6, 29.0, 29.2, 29.3, 29.3, 29.4, 29.4, 31.7,
7.5, 43.3, 73.0, 130.0, 156.0, 163.1, 203.3; HREIMS m=z
dqd, J ¼ 11:4, 6.3, 3.8 Hz); C NMR (75 MHz, CDCl
3
)
d 20.4, 20.8, 23.6, 26.7 (3C), 28.3, 29.0, 29.1, 29.3, 29.3
(3C), 29.9, 36.6, 37.6, 40.5, 43.4, 73.0, 78.3, 130.1, 156.1,
156.3, 163.4, 203.7; HREIMS m=z 424.3028 [M]
þ
08.2313 [M]
(308.2350 calcd for
C
19
H
32
O
3
).
þ
(S)-3-Tetradecanoyl-5,6-dihydro-4,6-dimethyl-2H-pyran-
2
D
) d
8
2
+
- one (dictyopyrone D) (4): Colorless powder; ½aꢀ
(424.3063 calcd for C H NO ).
24 42
5
1
84.7 (c 0.70, CHCl
3
); H NMR (500 MHz, CDCl
3
0
.88 (3H, t, J ¼ 6:9 Hz), 1.20–1.36 (20H, m), 1.44 (3H, d,
J ¼ 6:3 Hz), 1.61 (2H, quint, J ¼ 7:4 Hz), 2.01 (3H, s),
2
1
.31 (1H, dd, J ¼ 18:0, 3.7 Hz), 2.44 (1H, dd, J ¼ 18:0,
1.8 Hz), 2.70 (1H, dt, J ¼ 17:3, 7.4 Hz), 2.74 (1H, dt,
4.1.5. 10-Methoxymethoxydecanol (16a). To a solution of
1,10-decanediol (15a) (3.00 g, 17.2 mmol) in CH Cl
2
2
J ¼ 17:3, 7.4 Hz), 4.54 (1H, dqd, J ¼ 11:8, 6.3, 3.7 Hz);
(50 mL) was added N-ethyldiisopropylamine (9.00 mL,
51.6 mmol) and chloromethyl methyl ether (1.30 mL,
17.2 mmol) at 0 ꢁC. After being stirred at room temper-
ature for 14 h, the mixture was poured into 0.5 M
hydrochloric acid and extracted with ethyl acetate three
times. The organic layer was washed with brine, dried
over anhydrous sodium sulfate, and evaporated. The
residue was chromatographed over silica gel eluted by
13
C NMR (125 MHz, CDCl ) d 14.1, 20.4, 20.8, 22.6,
3
2
4
3
3.8, 29.2, 29.2, 29.3, 29.3, 29.4, 29.4, 29.6, 31.9, 37.7,
3.4, 73.0, 130.0, 156.0, 163.2, 203.4; HREIMS m=z
þ
36.2638 [M] (336.2664 calcd for C H O ). (S)-3-
36
21
3
Acetyl-5,6-dihydro-4,6-dimethyl-2H-pyran-2-one (10):
1
2
5
Colorless oil; ½aꢀ + 183:3 (c 0.418, CHCl
3
); H NMR
D
(
500 MHz, CDCl ) d 1.44 (3H, d, J ¼ 6:3 Hz), 2.08 (3H,
3
s), 2.34 (1H, dd, J ¼ 18:0, 3.7 Hz), 2.43 (3H, s), 2.46 (1H,
dd, J ¼ 18:0, 11.6 Hz), 4.55 (1H, dqd, J ¼ 11:6, 6.3,
n-hexane–ethyl acetate (9:1) to give 16a (1.64 g, 43%). 16a:
1
Colorless amorphous solid; H NMR (400 MHz, CDCl
3
)
13
3
3
1
.7 Hz); C NMR (125 MHz, CDCl ) d 20.3, 20.8, 31.1,
d 1.24–1.31 (12H, m), 1.55 (2H, quint, J ¼ 6:7 Hz), 1.59
13
3
7.9, 72.9, 130.0, 157.3, 163.1, 200.2; HREIMS m=z
(2H, quint, J ¼ 6:4 Hz), 3.36 (3H, s), 3.51 (2H, t,
þ
68.0792 [M] (168.0786 calcd for C
9
H
12
O
3
). (S)-3-
J ¼ 6:4 Hz), 3.61 (2H, t, J ¼ 6:7 Hz), 4.61 (2H, s);
C
Hexanoyl-5,6-dihydro-4,6-dimethyl-2H-pyran-2-one (11):
1
NMR (100 MHz, CDCl ) d 25.7, 26.2, 29.4, 29.4, 29.5,
3
25
Colorless oil; ½aꢀ +112:3 (c 1.15, CHCl ); H NMR
29.5, 29.7, 32.7, 55.0, 62.8, 67.8, 96.2; HREIMS m=z
D
3
þ
(
600 MHz, CDCl
3
) d 0.89 (3H, t, J ¼ 6:9 Hz), 1.25–1.38
217.1803 [M)H] (217.1802 calcd for C12
H
25
O
3
).

3210
H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
In the similar procedure, compound 16b was prepared
from 1,12-dodecanediol (15b) (yield 40%). 12-Meth-
oxymethoxydodecanol (16b): Colorless amorphous so-
by n-hexane–ethyl acetate (9:1) to give 18a (887 mg,
1
83%). 18a: Colorless oil; H NMR (400 MHz, CDCl ) d
3
1.20–1.37 (12H, m), 1.59 (2H, quint, J ¼ 6:7 Hz), 2.03
(2H, td, J ¼ 6:9, 6.3 Hz), 3.36 (3H, s), 3.51 (2H, t,
J ¼ 6:7 Hz), 4.07 (2H, d, J ¼ 5:3 Hz), 4.61 (2H, s), 5.62
1
lid; H NMR (300 MHz, CDCl
1
3
) d 1.24–1.31 (16H, m),
.57 (2H, quint, J ¼ 6:6 Hz), 1.59 (2H, quint,
J ¼ 6:6 Hz), 3.36 (3H, s), 3.52 (2H, t, J ¼ 6:6 Hz), 3.63
(1H, dt, J ¼ 15:3, 5.3 Hz), 5.66 (1H, dt, J ¼ 15:3,
13
13
(
2H, t, J ¼ 6:6 Hz), 4.62 (2H, s); C NMR (75 MHz,
CDCl ) d 25.7, 26.2, 29.4, 29.4, 29.4, 29.5, 29.5, 29.6,
9.7, 32.7, 55.0, 62.8, 67.8, 96.2; HREIMS m=z 245.2118
3
6.3 Hz); C NMR (100 MHz, CDCl ) d 26.2, 29.1, 29.1,
3
29.4, 29.5, 29.7, 32.2, 55.1, 63.8, 67.8, 96.3, 128.8, 133.3;
þ
2
HREIMS m=z 212.1740 [M)CH OH] (212.1775 calcd
3
þ
[
M)H] (245.2115 calcd for C14
H
29
O
3
).
24 2
for C13H O ).
In the similar procedure, compound 18b was prepared
from 17b (yield 90%). (E)-14-Methoxymethoxytetradec-
2-en-1-ol (18b): Colorless oil; H NMR (400 MHz,
4
(
.1.6. Ethyl (E)-12-methoxymethoxydodec-2-enoate
17a). PCC (2.65 g, 12.3 mmol) was added to a solution
of 16a (1.78 g, 8.14 mmol) in CH Cl (25 mL) at room
1
2
2
3
CDCl ) d 1.26–1.39 (16H, m), 1.59 (2H, quint,
temperature. After being stirred for 3 h, the mixture was
filtered through a Celite pad. The filter cake was washed
with diethyl ether, and the filtrate was concentrated to
give the crude aldehyde. This crude was added to a
solution of ethyl diethylphosphonoacetate (1.58 g,
J ¼ 6:6 Hz), 2.03 (2H, td, J ¼ 6:9, 6.3 Hz), 3.36 (3H, s),
3.51 (2H, t, J ¼ 6:6 Hz), 4.07 (2H, d, J ¼ 5:3 Hz), 4.61
(2H, s), 5.62 (1H, dt, J ¼ 15:4, 5.3 Hz), 5.69 (1H, dt,
13
J ¼ 15:4, 6.3 Hz); C NMR (100 MHz, CDCl ) d 26.2,
3
29.2, 29.2, 29.5, 29.5, 29.6, 29.6, 29.6, 29.8, 32.2, 55.1,
63.8, 67.9, 96.2, 128.7, 133.3; HREIMS m=z 240.2053
7.07 mmol) and sodium hydride (60% in mineral oil)
283 mg, 7.08 mmol) in benzene (10 mL) at room tem-
þ
(
[M)CH OH] (240.2088 calcd for C H O ).
3
15 28
2
perature. After being stirred for 4 h, the mixture was
poured into 0.5 M hydrochloric acid and extracted with
diethyl ether three times. The organic layer was washed
with brine, dried over anhydrous sodium sulfate, and
evaporated. The residue was chromatographed over
4.1.8. (E)-12-Methoxymethoxydodec-2-ene (19a). To a
solution of 18a (673 mg, 2.75 mmol) in THF (14 mL)
was added sulfur pyridine complex (1.09 g, 6.82 mmol)
at 0 ꢁC. After being stirred for 1 h at room temperature,
the mixture was treated with lithium aluminum hydride
(626 mg, 16.5 mmol), and further stirred for 7 h. The
reaction was quenched by methanol (10 mL), and the
mixture was filtered by a Celite pad. The filter cake was
washed with diethyl ether, and the filtrate was concen-
trated. The residue was chromatographed over silica gel
eluted by n-hexane–ethyl acetate (49:1) to give 19a
silica gel eluted by n-hexane–ethyl acetate (39:1) to give
1
1
7a (1.29 g, 55% from 16a). 17a: Colorless oil; H NMR
(
3
300 MHz, CDCl ) d 1.26–1.30 (10H, m), 1.29 (3H, t,
J ¼ 7:1 Hz), 1.45 (2H, quint, J ¼ 7:1 Hz), 1.59 (2H,
quint, J ¼ 6:7 Hz), 2.19 (2H, qd, J ¼ 7:1, 1.5 Hz), 3.36
(
3H, s), 3.52 (2H, t, J ¼ 6:7 Hz), 4.19 (2H, q,
J ¼ 7:1 Hz), 4.62 (2H, s), 5.89 (1H, dt, J ¼ 15:9, 1.5 Hz),
13
6
.91 (1H, dt, J ¼ 15:9, 7.1 Hz); C NMR (100 MHz,
CDCl ) d 14.3, 26.2, 28.0, 29.1, 29.3, 29.4, 29.5, 29.7,
2.2, 55.1, 60.1, 67.8, 96.3, 121.1, 149.3, 166.6; HREIMS
1
3
(332 mg, 53%). 19a: Colorless powder; H NMR
3
(300 MHz, CDCl
quint, J ¼ 6:6 Hz), 1.57 (3H, dq, J ¼ 3:3, 1.1 Hz), 1.94–
.96 (2H, m), 3.36 (3H, s), 3.56 (2H, t, J ¼ 6:6 Hz), 4.62
3
) d 1.23–1.37 (12H, m), 1.57 (2H,
þ
3 27 4
m=z 271.1927 [M)CH ] (271.1908 calcd for C15H O ).
1
13
In the similar procedure, compound 17b was prepared
from 16b (yield 67%). Ethyl (E)-14-methoxymethoxy-
3
(2H, s), 5.35–5.43 (2H, m); C NMR (75 MHz, CDCl )
d 17.7, 26.1, 29.0, 29.3, 29.4, 29.4, 29.5, 29.6, 32.5, 55.0,
1
þ
tetradec-2-enoate (17b): Colorless oil;
300 MHz, CDCl
H
NMR
67.8, 96.4, 124.6, 131.7; HREIMS m=z 228.2058 [M]
(
3
) d 1.26–1.38 (14H, m), 1. 29 (3H, t,
28 2
(228.2088 calcd for C14H O ).
J ¼ 7:1 Hz), 1.45 (2H, quint, J ¼ 7:1 Hz), 1.59 (2H,
quint, J ¼ 6:9 Hz), 2.19 (2H, qd, J ¼ 7:1, 1.4 Hz), 3.36
In the similar procedure, compound 19b was prepared
from 18b (yield 67%). (E)-14-Methoxymethoxytetradec-
(
3H, s), 3.52 (2H, t, J ¼ 6:9 Hz), 4.18 (2H, q,
1
J ¼ 7:1 Hz), 4.62 (2H, s), 5.81 (1H, dt, J ¼ 15:7, 1.4 Hz),
2-ene (19b): Colorless powder; H NMR (300 MHz,
CDCl ) d 1.20–1.32 (16H, m), 1.59 (2H, quint,
13
6
.96 (1H, dt, J ¼ 15:7, 7.1 Hz); C NMR (100 MHz,
3
CDCl ) d 14.3, 26.2, 28.1, 29.2, 29.4, 29.5, 29.5, 29.6,
J ¼ 6:6 Hz), 1.64 (3H, dq, J ¼ 3:6, 1.2 Hz), 1.94–1.96
13
3
2
1
9.6, 29.8, 32.2, 55.1, 60.1, 67.9, 96.3, 121.1, 149.3,
þ
(2H, m), 3.36 (3H, s), 3.52 (2H, t, J ¼ 6:6 Hz), 4.62 (2H,
66.6; HREIMS m=z 313.2414 [M)H] (313.2377 calcd
3
s), 5.39–5.43 (2H, m); C NMR (75 MHz, CDCl ) d
for C H O ).
18.0, 26.3, 29.2, 29.3, 29.4, 29.5, 29.6, 29.6, 29.7, 29.8,
18
33
4
3
2
2.7, 55.1, 67.9, 96.3, 124.4, 131.6; HREIMS m=z
þ
56.2404 [M] (256.2401 calcd for C16
32 2
H O ).
4.1.7. (E)-12-Methoxymethoxydodec-2-en-1-ol (18a). To
a solution of 17a (1.26 g, 4.38 mmol) in CH Cl (19 mL)
2
2
was added diisobutylaluminum hydride (1 M solution in
toluene, 13.0 mL, 13.0 mmol) at )20 ꢁC. After being
stirred for 1 h, the solution was poured into saturated
Rochelle salt solution and extracted with diethyl ether
three times. The organic layer was washed with brine,
dried over anhydrous sodium sulfate, and evaporated.
The residue was chromatographed over silica gel eluted
4.1.9. (E)-10-Dodecen-l-ol (20a). A solution of 19a
(56.9 mg, 0.25 mmol) in THF (1 mL) and 2 M hydro-
chloric acid (1 mL) was refluxed for 4 h. The mixture was
poured into 0.5 M sodium hydroxide solution, and
extracted with ethyl acetate three times. The organic
layer was washed with brine, dried over anhydrous
sodium sulfate, and evaporated. The residue was

H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
3211
chromatographed over silica gel eluted by n-hexane–
ethyl acetate (4:1) to give 20a (38.9 mg, 85%). 20a:
40.0, 43.4, 73.1, 130.0, 156.1, 163.2, 203.4; HREIMS m=z
þ
323.2465 [M] (323.2460 calcd for C19
H
33NO
3
).
1
Colorless powder; H NMR (300 MHz, CDCl ) d 1.24–
3
1
.31 (12H, m), 1.56 (2H, quint, J ¼ 6:6 Hz), 1.64 (3H,
dq, J ¼ 3:3, 1.4 Hz), 1.92–1.96 (2H, m), 3.63 (2H, t,
4.1.12. (R)-3-Dodecanoyl-5,6-dihydro-4,6-dimethyl-2H-
pyran-2-one (23). In the similar way from 7c to 3 com-
pound 23 was synthesized by the use of (2R,4R)-2,4-
13
J ¼ 6:6 Hz), 5.34–5.48 (2H, m); C NMR (75 MHz,
CDCl ) d 18.0, 25.3, 29.2, 29.4, 29.5, 29.5, 29.6, 29.6,
2.8, 63.1, 124.5, 131.6; HREIMS m=z 166.1709
3
3
pentanediol instead of (2S,4S)-2,4-pentanediol. 23:
þ
28
[
M)H O] (166.1720 calcd for C H ).
Colorless amorphous solid; ½aꢀ ꢁ 69:2 (c 1.00, CHCl ).
2
12 22
D
Other spectral data were identical with those of dictyo-
3
In the similar procedure, compound 20b was prepared
from 19b (yield 92%). (E)-12-Tetradecen-1-ol (20b):
pyrone C (3).
1
Colorless powder; H NMR (300 MHz, CDCl ) d 1.23–
3
1
.31 (16H, m), 1.56 (2H, quint, J ¼ 6:7 Hz), 1.64 (3H,
4.1.13. Methyl 3-oxotetradecanoate (24). A solution of
7c (362 mg, 1.110 mmol) in methanol (4 mL) was ref-
luxed for 2 h. The mixture was concentrated, and the
residue was chromatographed over silica gel eluted by n-
hexane–ethyl acetate (19:1) to give 24 (255 mg, 90%). 24:
dq, J ¼ 3:4, 1.4 Hz), 1.92–1.99 (2H, m), 3.62 (2H, t,
13
J ¼ 6:7 Hz), 5.39–5.43 (2H, m); C NMR (75 MHz,
CDCl ) d 18.0, 25.8, 29.2, 29.3, 29.4, 29.5, 29.6, 29.6,
9.6, 29.7, 32.8, 63.1, 124.4, 131.6; HREIMS m=z
3
2
2
þ
1
12.2118 [M] (212.2139 calcd for C H O).
Colorless amorphous solid; H NMR (600 MHz,
CDCl33) d 0.88 (3H, t, J ¼ 6:8 Hz), 1.25–1.35 (16H, m),
14
28
1
.59 (2H, quint, J ¼ 7:3 Hz), 2.53 (2H, t, J ¼ 7:3 Hz),
13
4
.1.10. (E)-10-Dodecenoic acid (5a). To a solution of 20a
3.45 (2H, s), 3.74 (3H s); C NMR (150 MHz, CDCl ) d
3
(
(
475 mg, 2.58 mmol) in DMF (10 mL) was added PDC
3.82 g, 10.1 mmol) at room temperature. After being
14.2, 22.7, 23.5, 29.0, 29.3, 29.4, 29.4, 29.5, 29.6, 31.9,
43.1, 49.0, 52.3, 167.6, 202.7; HREIMS m=z 256.2003
þ
stirred for 12 h, the mixture was filtered by a Celite pad.
The filter cake was washed with diethyl ether, and the
filtrate was concentrated. The residue was chromato-
[M] (256.2037 calcd for C H O ).
28
15
3
graphed over silica gel eluted by n-hexane–ethyl acetate
1
4.1.14. 1,1-Dimethyl-3-oxobutyl 3-oxotetradecaoate (25).
A solution of 7c (278 mg, 0.85 mmol) and 4-hydroxy-4-
methyl-2-pentanone (370 lL 2.99 mmol) in toluene
(4.5 mL) was refluxed for 2 h. The mixture was concen-
trated, and the residue was chromatographed over silica
gel eluted by n-hexane–ethyl acetate (9:1) to give 25
(
4:1) to give 5a (280 mg, 55%). 5a: Colorless powder; H
NMR (300 MHz CDCl ) d 1.24–1.31 (10H, m) 1.58–1.65
3
(
2
(
2H, m) 1.63 (3H, dq, J ¼ 3:4, 1.4 Hz) 1.93–1.96 (2H, m)
13
.35 (2H, t, J ¼ 7:4 Hz) 5.39–5.43 (2H, m); C NMR
75 MHz, CDCl
3
) d 17.8, 24.5, 28.9, 29.0, 29.1, 29.2,
1
2
1
9.5, 32.5, 33.9, 124.7, 131.7, 180.0; HREIMS m=z
(251 mg, 87%). 25: Colorless oil; H NMR (500 MHz,
CDCl ) d 0.88 (3H, t, J ¼ 6:8 Hz), 1.20–1.35 (16H, m),
þ
98.1612 [M] (198.1619 calcd for C H O ).
12
22
2
3
1
.58 (2H, quint, J ¼ 7:4 Hz), 1.54 (6H, s), 2.15 (3H, s),
13
In the similar procedure, compound 5b was prepared
from 20b (yield 59%). (E)-12-Tetradecenoic acid (5b):
2.51 (2H, t J ¼ 7:4 Hz), 3.04 (2H, s), 3.36 (2H, s);
C
NMR (125 MHz, CDCl ) d 14.2, 22.7, 23.5, 26.4 (2C),
3
1
Colorless powder; H NMR (300 MHz, CDCl ) d 1.27–
29.1, 29.3, 29.3, 29.4, 29.5, 29.6, 31.8, 31.9, 43.1, 50.4,
52.0, 81.6, 166.5, 203.1, 205.4; HREIMS m=z 340.2663
3
1
1
5
2
1
.30 (14H, m) 1.58–1.65 (2H, m) 1.64 (3H, dq, J ¼ 3:3,
þ
.4 Hz) 1.93–1.96 (2H, m) 2.35 (2H, t, J ¼ 7:4 Hz) 5.35–
[M] (340.2612 calcd for C20
36 4
H O ).
13
.48 (2H, m, H-12); C NMR (75 MHz, CDCl ) d 18.0,
3
4.7, 29.1, 29.2, 29.3, 29.5, 29.5, 29.6, 29.7, 32.7, 34.2,
þ
In the similar procedure, compound 26–28 was prepared
(yield 73% (26), 51% (27), 67% (28)) by the reaction of 7c
with 4-hydroxy-2-butanone, (3S,5S)-2,6-dimethyl-3,5-
heptanediol and (2S,3S)-2,3-butanediol, respectively. 3-
24.4, 131.6, 180.3; HREIMS m=z 226.1920 [M]
(
226.1931 calcd for C H O ).
14 26 2
Oxobutyl 3-oxotetradecanoate (26): Colorless needle;
1
4
.1.11. (S)-3-(12-Aminododecanoyl)-5,6-dihydro-4,6-di-
H NMR (500 MHz, CDCl ) d 0.88 (3H, t, J ¼ 6:9 Hz),
3
methyl-2H-pyran-2-one hydrochloride (22). Compound
4 (32.9 mg, 0.078 mmol) was treated with 10% hydro-
1.20–1.35 (16H, m), 1.57 (3H, quint, J ¼ 7:3 Hz), 2.19
(3H, s), 2.50 (2H, t, J ¼ 7:3 Hz), 2.79 (2H, t,
1
1
3
gen chloride containing methanol (2 mL) at room tem-
perature for 3 h. The mixture was concentrated, and the
residue was chromatographed over silica gel eluted by
chloroform–methanol (19:1) to give 22 (23.9 mg, 89%).
22: Colorless powder; ½aꢀ + 69:1 (c 0.74, MeOH); H
NMR (500 MHz, CDCl
J ¼ 6:3 Hz), 3.42 (2H, s), 4.40 (2H, t, J ¼ 6:3 Hz);
C
NMR (125 MHz, CDCl ) d 14.0, 22.6, 23.4, 29.0, 29.3,
3
29.3, 29.4, 29.4, 29.5, 30.2, 31.8, 42.0, 43.1, 49.0, 60.0,
þ
167.1, 202.8, 205.3; HREIMS m=z 312.2296 [M]
28
1
(312.2301 calcd for C H O ). (1S,3S)-3-Hydroxy-4-
methyl-1-isopropylpentyl 3-oxotetradecanoate (27):
D
18 32
4
3
) d 1.25–1.38 (14H, m) 1.44
1
(
(
3H, d, J ¼ 6:3 Hz) 1.60 (2H, quint, J ¼ 7:4 Hz) 1.77
3
Colorless oil; H NMR (400 MHz, CDCl ) d 0.88 (3H, t,
2H, quint, J ¼ 7:6 Hz) 2.01 (2H, s) 2.32 (2H, dd,
J ¼ 6:9 Hz), 0.93 (3H, d, J ¼ 6:8 Hz), 0.93 (3H, d,
J ¼ 6:8 Hz), 0.94 (3H, d, J ¼ 6:8 Hz), 0.94 (3H, d,
J ¼ 6:8 Hz), 1.26–1.35 (16H, m), 1.50–1.68 (5H, m), 1.85
(1H, m), 2.53 (2H, t, J ¼ 7:4 Hz), 3.29 (1H, ddd,
J ¼ 10:3, 5.5, 2.0 Hz), 3.49 (2H, s), 5.02 (1H, ddd,
J ¼ 18:0, 3.7 Hz), 2.45 (1H, dd, J ¼ 18:0, 11.6 Hz) 2.71
(
1H, dt, J ¼ 17:3, 7.4 Hz) 2.73 (1H, dt, J ¼ 17:3,
7
6
2
.4 Hz), 2.99 (2H, t, J ¼ 7:6 Hz) 4.56 (1H, dqd, J ¼ 11:6,
13
.3, 3.7 Hz); C NMR (125 MHz, CDCl ) d 20.4, 20.8,
3
13
3.7, 26.5, 27.6, 29.0, 29.1, 29.3, 29.3, 29.4, 29.4, 37.7,
J ¼ 10:4, 5.3, 2.0 Hz); C NMR (100 MHz, CDCl
3
) d

3212
H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
1
2
7
4.2, 17.8, 17.9, 18.6, 18.8, 22.7, 23.6, 29.0, 29.3, 29.4,
9.5, 29.6, 29.6, 31.9, 32.1, 33.7, 35.9, 43.3, 49.4, 71.7,
7.3, 168.1, 202.8; HREIMS m=z 384.3266 [M]
washed with brine, dried over anhydrous sodium sulfate,
and evaporated. The residue was chromatographed over
silica gel eluted by n-hexane–ethyl acetate (4:1) to give
þ
28
(384.3237 calcd for C23
methylpropyl 3-oxotetradecanoate (28): Colorless pow-
der; H NMR (400 MHz, CDCl ) d 0.88 (3H, t,
H
44
O
4
). (1S,2S)-2-Hydroxy-1-
31 (30.3 mg, 13%). 31: Colorless amorphous solid; ½aꢀ
D
) d
1
)52.2 (c 1.12, CHCl
3
); H NMR (500 MHz, CDCl
3
1
0.88 (3H, t, J ¼ 6:9 Hz), 1.02 (3H, d, J ¼ 6:5 Hz), 1.05
(3H, d, J ¼ 6:5 Hz), 1.05 (3H, d, J ¼ 6:5 Hz), 1.06 (3H,
d, J ¼ 6:5 Hz), 1.20–1.35 (16H, m), 1.62 (2H, quint,
J ¼ 7:5 Hz), 1.98 (1H, m), 2.25 (1H, dd, J ¼ 17:6,
11.9 Hz), 2.33 (1H, dd, J ¼ 17:6, 3.8 Hz), 2.67 (1H, dt,
J ¼ 17:4, 7.5 Hz), 2.73 (1H, dt, J ¼ 17:4, 7.5 Hz), 2.84
3
J ¼ 6:8 Hz), 1.20 (3H, d, J ¼ 6:6 Hz), 1.21 (3H, d,
J ¼ 6:6 Hz), 1.24–1.30 (16H, m), 1.59 (2H, quint,
J ¼ 7:3 Hz), 2.52 (2H, t, J ¼ 7:3 Hz), 3.50 (2H, s), 3.73
(
1H, quint, J ¼ 6:6 Hz), 4.85 (1H, quint, J ¼ 6:6 Hz);
1
3
C NMR (100 MHz, CDCl ) d 14.2, 16.4, 18.7, 22.7,
3
2
7
3.5, 29.0, 29.3, 29.4, 29.4, 29.5, 29.6, 31.9, 43.3, 49.5,
þ
(1H, sept, J ¼ 6:5 Hz), 4.07 (1H, ddd, J ¼ 11:9, 6.5,
13
0.7, 76.4, 166.5, 203.8. HREIMS m=z 314.2488 [M]
3.8 Hz); C NMR (125 MHz, CDCl ) d 14.2, 17.8, 18.1,
3
(
314.2455 calcd for C18
H
34
O
4
).
19.4 (2C), 21.0 (2C), 22.7, 23.7, 25.1, 29.2, 29.4, 29.5,
2
1
9.5, 29.7, 29.7, 31.4, 31.9 (2C), 44.0, 81.9, 128.9, 163.0,
þ
63.5, 203.9; HREIMS m=z 364.2965 [M] (364.2975
4
.1.15.
3-Dodecanoyl-5,6-dihydro-4,6,6-trimethyl-2H-
40 3
calcd for C23H O ).
pyran-2-one (29). Compound 25 (207 mg, 0.61 mmol)
dissolved in ethanol (5 mL) was treated with sodium
ethoxide (45.6 mg, 0.67 mmol) at room temperature for
4
2
.1.17. 3-Dodecanoyl-5-hydroxy-4,5-dimethyl-5H-furan-
-one (32). PCC (778 mg, 3.61 mmol) was added to a
Cl (6 mL) at
8
h. The mixture was poured into 0.5 M hydrochloric acid
and extracted with diethyl ether three times. The organic
layer was washed with brine, dried over anhydrous so-
dium sulfate, and evaporated. The residue was chroma-
tographed over silica gel eluted by n-hexane–ethyl acetate
solution of 28 (379 mg, 1.20 mmol) in CH
2
2
room temperature. After being stirred for 5 h, the mix-
ture was filtered through a Celite pad. The filter cake
was washed with diethyl ether, and the filtrate was
concentrated. The residue was chromatographed over
(
4:1) to give 29 (198 mg, 81%). 29: Colorless amorphous
1
solid; H NMR (500 MHz, CDCl ) d 0.88 (3H, t,
3
silica gel eluted by n-hexane–ethyl acetate (9:1) to give
1
J ¼ 6:7 Hz), 1.20–1.35 (16H, m), 1.46 (6H, s), 1.61 (2H,
3
2 (103 mg, 28%). 32: Colorless powder; H NMR
) d 0.88 (3H, t, J ¼ 6:9 Hz), 1.24–1.30
quint, J ¼ 7:4 Hz), 1.99 (3H, s), 2.45 (2H, s), 2.73 (2H, t,
(
(
(
500 MHz, CDCl
16H, m), 1.59 (2H, quint, J ¼ 7:3 Hz), 1.67 (3H, s), 2.34
3
1
3
J ¼ 7:4 Hz); C NMR (125 MHz, CDCl
3
) d 14.0, 21.1,
2.6, 23.8, 27.4 (2C), 29.1, 29.3, 29.4, 29.4, 29.5, 29.5,
2
3
3H, s), 2.87 (1H, dt, J ¼ 17:9, 7.3 Hz), 2.92 (1H, dt,
1.9, 42.2, 43.5, 78.9, 129.7, 154.2, 162.5, 203.4; HRE-
þ
13
J ¼ 17:9, 7.3 Hz); C NMR (125 MHz, CDCl
3
) d 14.1,
2.6, 22.7, 23.2, 23.3, 29.1, 29.3, 29.4, 29.5, 29.6 (2C),
IMS m=z 322.2523 [M] (322.2506 calcd for C20
34 3
H O ).
2
3
1.9, 42.6, 104.8, 125.2, 168.0, 173.9, 198.2; HREIMS
þ
In the similar procedure, compound 30 was prepared
from 26 (yield 27%). 3-Dodecanoyl-5,6-dihydro-4-me-
thyl-2H-pyran-2-one (30). Colorless amorphous solid;
m=z 310.2128 [M] (310.2142 calcd for C18
30 4
H O ).
1
H NMR (500 MHz, CDCl
.20–1.35 (16H, m), 1.62 (2H, quint, J ¼ 7:3 Hz), 2.04
3
) d 0.88 (3H, t, J ¼ 6:9 Hz),
1
(
4.1.18.
(33). To
(S)-2-(1-Methyl-3-oxobutyl)isoindole-1,3-dione
solution of (2R,4R)-2,4,-pentanediol
3H, s), 2.49 (2H, t, J ¼ 6:2 Hz), 2.73 (2H, t,
a
13
J ¼ 7:3 Hz), 4.38 (2H, t, J ¼ 6:2 Hz);
C NMR
125 MHz, CDCl ) d 14.1, 20.9, 22.6, 23.8, 29.1, 29.3,
(146 mg, 1.41 mmol) in THF (5 mL) was added triphenyl
phosphine (369 mg, 1.41 mmol), phthalimide (207 mg,
1.41 mmol), and diethyl azodicarboxylate (245 mg,
1.41 mmol) at 0 ꢁC. After being stirred for 15 h at room
temperature, the mixture was concentrated. The residue
was chromatographed over silica gel eluted by n-hex-
ane–ethyl acetate (9:1) to give (1S,3R)-2-(3-hydroxy-1-
methylbutyl)isoindole-1,3-dione (88.4 mg, 38%).
(
3
2
9.3, 29.4, 29.6, 29.6, 30.6, 31.9, 43.4, 65.2, 130.4, 156.7,
þ
1
calcd for C H O ).
62.5, 203.3; HREIMS m=z 294.2221 [M] (294.2193
18
30
3
4
.1.16. (S)-3-Dodecanoyl-5,6-dihydro-4,6-diisopropyl-2H-
pyran-2-one (31). PCC (938 mg, 4.35 mmol) was added
to a solution of 27 (557 mg, 1.45 mmol) in CH Cl
8 mL) at room temperature. After being stirred for 8 h,
2
2
This compound (67.4 mg, 0.29 mmol) was dissolved in
CH Cl (2 mL), and PCC (101 mg, 0.46 mmol) was
(
2
2
the mixture was filtered through a Celite pad. The filter
cake was washed with diethyl ether, and the filtrate was
concentrated. The residue was chromatographed over
silica gel eluted by n-hexane–ethyl acetate (9:1) to give
(S)-4-methyl-1-isopropyl-3-oxopentyl 3-oxotetradecan-
oate (424 mg, 76%).
added to the solution at room temperature. After being
stirred for 3 h, the mixture was filtered through a Celite
pad. The filter cake was washed with diethyl ether, and
the filtrate was concentrated. The residue was chroma-
tographed over silica gel eluted by n-hexane–ethyl ace-
tate (9:1) to give 33 (42.8 mg, 65%). 33: Colorless
27
1
powder; ½aꢀ + 2:0 (c 4.99, CHCl ); H NMR (500 MHz,
D
3
This compound (251 mg, 0.66 mmol) dissolved in etha-
nol (5 mL) was treated with sodium ethoxide (47.6 mg,
CDCl
(1H, dd, J ¼ 17:7, 6.4 Hz), 3.30 (1H, dd, J ¼ 17:7,
7.9 Hz), 4.84 (1H, m), 7.70 (2H, dd, J ¼ 5:5, 3.1 Hz),
3
) d 1.45 (3H, d, J ¼ 6:9 Hz), 2.14 (3H, s), 3.01
0
.70 mmol) at room temperature for 8 h. The mixture
13
was poured into 0.5 M hydrochloric acid and extracted
with diethyl ether three times. The organic layer was
7.81 (2H, dd, J ¼ 5:5, 3.1 Hz); C NMR (125 MHz,
3
CDCl ) d 18.8, 30.0, 42.4, 46.7, 123.1 (2C), 131.9 (2C),

H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
3213
13
1
33.8 (2C), 168.1 (2C), 205.7; HREIMS m=z 231.0897
C NMR (75 MHz, CDCl
28.9, 29.2, 29.3, 29.4, 29.5, 29.6, 30.3, 31.7, 41.9, 43.7,
3
) d 13.9, 20.0, 22.5, 23.2,
þ
[
M] (231.0895 calcd for C13
H
13NO
3
).
4
8.8, 49.1, 165.1, 206.9, 207.4; HREIMS m=z 325.2583
þ
[
M] (325.2615 calcd for C19
H
35NO
3
).
4
.1.19.
(S)-2-[1-Methyl-2-(2-methyl-1,3-dioxan-2-
yl)ethyl]isoindole-1,3-dione (34). To a solution of 33
196 mg, 0.85 mmol) in benzene (5 mL) was added 1,3-
(
4.1.22. (S)-3-Dodecanoyl-5,6-dihydro-4,6-dimethyl-1H-
pyridin-2-one (37). Compound 36 (302 mg, 0.93 mmol)
dissolved in ethanol (7 mL) was treated with sodium
ethoxide (69.4 mg, 1.02 mmol) at room temperature for
6 h. The mixture was poured into 0.5 M hydrochloric
acid and extracted with diethyl ether three times. The
organic layer was washed with brine, dried over anhy-
drous sodium sulfate, and evaporated. The residue was
chromatographed over silica gel eluted by n-hexane–
ethyl acetate (2:1) to give 37 (103 mg, 36%). 37: Colorless
propanediol (310 lL, 4.23 mmol) and p-toluenesulfonic
acid (9.6 mg, 0.05 mmol). After being refluxed for 4 h,
the mixture was poured into saturated sodium bicar-
bonate solution, and extracted with diethyl ether three
times. The organic layer was washed with brine, dried
over anhydrous sodium sulfate, and evaporated. The
residue was chromatographed over silica gel eluted by n-
hexane–ethyl acetate (7:3) to give 34 (212 mg, 86%). 34:
1
Colorless oil; H NMR (300 MHz, CDCl ) d 1.30 (1H,
3
29
1
m), 1.40 (3H, s), 1.48 (3H, d, J ¼ 7:1 Hz), 1.76 (1H, dt,
powder; ½aꢀ + 80:0 (c 1.18, CHCl
3
);
H
NMR
D
(500 MHz, CDCl
J ¼ 13:5, 6.0 Hz), 1.81 (1H, dd, J ¼ 14:8, 3.3 Hz), 2.84
3
) d 0.89 (3H, t, J ¼ 6:9 Hz), 1.23–1.33
(
3
3
1H, dd, J ¼ 14:8, 9.9 Hz), 3.49 (1H, dd, J ¼ 6:0,
(16H, m), 1.61 (2H, quint, J ¼ 7:4 Hz), 1.92 (3H, s), 2.22
.3 Hz), 3.69–3.86 (4H, m), 4.84 (1H, dqd, J ¼ 9:9, 7.1,
.3 Hz), 7.70 (2H, dd, J ¼ 5:5, 3.1 Hz), 7.81 (2H, dd,
(1H, dd, J ¼ 17:2, 11.1 Hz), 2.29 (1H, dd, J ¼ 17:2,
13
5.2 Hz), 2.71 (2H, t, J ¼ 7:4 Hz), 3.70 (1H, m), 6.39 (1H,
13
J ¼ 5:5, 3.1 Hz); C NMR (75 MHz, CDCl ) d 19.9,
s); C NMR (125 MHz, CDCl ) d 14.0, 20.7, 20.9, 22.6,
3
3
2
0.0, 25.0, 42.2, 42.5, 59.7, 59.8, 98.3, 122.7 (2C), 132.3
23.8, 29.2, 29.3, 29.4, 29.4, 29.5, 29.5, 31.8, 38.5, 43.9,
45.6, 132.7, 150.2, 165.2, 205.3; HREIMS m=z 307.2512
(
2C), 133.4 (2C), 168.5 (2C); HREIMS m=z 289.1292
þ
þ
[
M] (289.1313 calcd for C H NO ).
[M] (307.2510 calcd for C H NO ).
19 33 2
16
19
4
4
.1.20.
(S)-N-[l-Methyl-2-(2-methyl-1,3-dioxan-2-
4.1.23. Cell culture of D. discoideum and developmental
conditions. Vegetative cells of D. discoideum Ax-2 (clone
MS) were axenically grown in modified HL-5 medium
yl)ethyl]-3-oxotetradecanamide (35). To a solution of
4 (85.0 mg, 0.29 mmol) in methanol (2 mL) was added
3
12
hydrazine monohydrate (300 mL, 6.21 mmol). After
being refluxed for 1 h, the mixture was poured into 1 M
sodium hydroxide solution, and extracted with CH Cl
2 2
three times. The organic layer was concentrated to give
crude amine. This crude was dissolved in toluene (2 mL),
and 7c (145 mg, 0.44 mmol) was added to the solution.
After being refluxed for 2 h, the mixture was evaporated.
The residue was chromatographed over silica gel eluted
(PS medium). Growth kinetics of Ax-2 cells with or
without dictyopyrone derivatives was monitored by cell
counts under a hematocytometer. Ax-2 cells were grown
6
up to a cell density of 5 · 10 cells/mL, then cells were
5
diluted into a cell density of 5 · 10 cells/mL in fresh
growth medium with or without tested compounds. In
another experiment, cells were grown into a low cell
5
density of 5 · 10 cells/mL, followed by addition of tes-
by n-hexane–diethyl ether (4:1) to give 35 (67.9 mg,
1
ted compounds. These cultures were shaken at 22 ꢁC for
subsequent cell counts. To allow cells to differentiate
under submerged conditions, exponentially growing
cells were harvested, washed twice in BSS (Bonner’s salt
6
CDCl
0%). 35: Colorless powder; H NMR (500 MHz,
) d 0.88 (3H, t, J ¼ 6:7 Hz), 1.22 (3H, d,
3
J ¼ 6:6 Hz), 1.23–1.32 (16H, m), 1.43 (3H, s), 1.57 (2H,
16
quint, J ¼ 7:2 Hz), 1.77 (1H, dd, J ¼ 14:6, 4.9 Hz), 1.86
solution), and settled down in a 24-well titer plate
containing various concentrations of dictyopyrones or
their analogues and were incubated at 22 ꢁC (Charts 1
and 2).
(
1H, dd, J ¼ 14:6, 8.7 Hz), 1.85–1.95 (2H, m), 2.53 (2H,
t, J ¼ 7:2 Hz), 3.32 (2H, s), 3.80–3.90 (2H, m), 3.90–4.04
13
(
(
2
5
3
2H, m), 4.15 (1H, dqd, J ¼ 8:7, 6.6, 4.9 Hz); C NMR
125 MHz, CDCl ) d 13.9, 19.1, 21.5, 22.5, 23.3, 25.2,
8.9, 29.2, 29.2, 29.3, 29.4, 29.5, 31.7, 42.6, 43.5, 45.6,
3
0.1, 59.6, 59.6, 98.7, 164.8, 206.7; HREIMS m=z
83.3019 [M] (383.3033 calcd for C22
4.1.24. Assay for cell growth in K562 cells . Human leu-
þ
H41NO
4
).
kemia K562 cells were maintained at 37 ꢁC (5% CO
2
) in
tissue culture dishes filled with a growth medium (an
RPMI1640 medium with 10% fetal bovine serum, 25 lg/
mL penicillin, and 50 lg/mL streptomycin; designated
RPMI). For the assay for cell growth, K562 cells were
incubated in a 12-well plate, each well containing 1 mL
4
.1.21.
(S)-N-(1-Methyl-3-oxobutyl)-3-oxotetradecan-
amide (36). A solution of 35 (449 mg, 1.17 mmol) in
0% acetic acid (10 mL) was stirred for 2 h at room
temperature. The mixture was concentrated, and the
8
4
of RPMI (3–5 · 10 cells/mL) in the presence or absence
residue was chromatographed over silica gel eluted by n-
hexane–diethyl ether (4:1) to give 36 (342 mg, 90%). 36:
Colorless powder; H NMR (300 MHz, CDCl
of drugs. After 3 days, 50 lL of Alamar Blue was added
to each well, and after 1–2 h incubation at 37 ꢁC (5–8%
1
3
) d 0.88
2
CO ), 150 lL of each of the sample solutions was
(
(
(
(
2H, t, J ¼ 6:7 Hz), 1.23 (3H, d, J ¼ 6:9 Hz), 1.24–1.32
transferred into a 96-well plate, and absorbance at
570 nm (reference at 595 nm) was measured with a
microplate reader (Bio-Rad, Model 550). A cell number
was given as a ratio of the absorbance (% of control).
16H, m), 1.57 (2H, quint, J ¼ 7:0 Hz), 2.16 (3H, s), 2.52
2H, t, J ¼ 7:3 Hz), 2.60 (1H, dd, J ¼ 16:7, 6.3 Hz), 2.73
1H, dd, J ¼ 16:7, 5.4 Hz), 3.31 (2H, s), 4.34 (1H, m);

3214
H. Kikuchi et al. / Bioorg. Med. Chem. 12 (2004) 3203–3214
6. Suzuki, T.; Oka, H.; Okura, A.; Asahi, K.; Takahashi, N.
J. Antibiot. 1986, 39, 869–871.
Acknowledgements
7
. Asahi, K.; Sakurai, A.; Takahashi, N.; Kubohara, Y.;
Okamoto, K.; Tanaka, Y. Biochem. Biophys. Res. Com-
mun. 1995, 208, 1036–1039.
This work was supported in part by a Grant-in-Aid for
Scientific Research (No. 15710153) from the Ministry of
Education, Science, Sports and Culture of Japan, and a
scholarship from Mitsubishi Trust Yamamuro memo-
rial scholarship foundation.
8
9
. Kubohara, Y. Biochem. Biophys. Res. Commun. 1997, 236,
4
. (a) Kubohara, Y.; Kimura, C.; Tatemoto, K. Dev. Growth
Differ. 1995, 37, 711–716; (b) Kubohara, Y.; Saito, Y.;
Tatemoto, K. FEBS Lett. 1995, 359, 119–122.
18–422.
References and notes
10. Kubohara, Y.; Okamoto, K.; Tanaka, Y.; Asahi, K.;
Sakurai, A.; Takahashi, N. FEBS Lett. 1993, 322, 73–
75.
11. Takaya, Y.; Kikuchi, H.; Terui, Y.; Komiya, J.; Furu-
kawa, K.; Seya, K.; Motomura, S.; Ito, A.; Oshima, Y. J.
Org. Chem. 2000, 65, 985–989.
1
. Dictyostelium. A Model System for Cell and Develop-
mental Biology, Frontiers Science Series No. 21; Maeda,
Y; Inoue, K.; Takeuchi, I., Eds.; Universal Academy:
Tokyo, 1997.
2
3
4
. Morris, H. R.; Taylor, G. W.; Masento, M. S.; Jermyn,
K. A.; Kay, R. R. Nature 1987, 328, 811–814.
. Abe, H.; Uchiyama, M.; Tanaka, Y.; Saito, H. Tetra-
hedron Lett. 1976, 42, 3807–3810.
. Konijn, T. M.; van de Meene, J. G.; Bonner, J. T.;
Barkley, D. S. Proc. Natl. Acad. Sci. U.S.A. 1976, 58,
12. Maeda, Y.; Kikuchi, H.; Sasaki, K.; Amagai, A.; Sekiya,
J.; Takaya, Y.; Oshima, Y. Protoplasma 2003, 221, 185–
192.
13. Oikawa, Y.; Sugamo, K.; Yonemitsu, O. J. Org. Chem.
1978, 43, 2087–2088.
14. Corey, E. J.; Achiwa, K. J. Org. Chem. 1969, 34, 3667–
3668.
1152–1154.
5
. Oka, H.; Asahi, K.; Morishima, H.; Sanada, M.; Shiratori,
K.; limura, Y.; Sakurai, T.; Uzawa, J.; Iwadare, S.;
Takahashi, N. J. Antibiot. 1985, 38, 1100–1102.
15. Pak, C. S.; Yang, H. C.; Choi, E. B. Synthesis 1992, 1213–
1214.
16. Bonner, J. T. J. Exp. Zool. 1947, 106, 1–26.