Taurospongin A, a Novel Acetylenic Fatty Acid Derivative Inhibiting DNA Polymerase β and HIV Reverse Transcriptase from Sponge Hippospongia sp

Article abstract of DOI:10.1021/jo970206r

Taurospongin A (1), a novel acetylene-containing natural product consisting of a taurine and two fatty acid residues, has been isolated from the Okinawan marine sponge Hippospongia sp. and its structure elucidated by spectral data and chemical means. Taurospongin A (1) exhibited potent inhibitory activity against DNA polymerase β and HIV reverse transcriptase. The absolute configurations of taurospongin A (1) were established to be 3R, 7S, and 9R by synthesis of the MTPA ester of a degradation product of 1.

Full text of DOI:10.1021/jo970206r

J . Org. Chem. 1997, 62, 3831-3836
3831
Ta u r osp on gin A, a Novel Acetylen ic F a tty Acid Der iva tive
In h ibitin g DNA P olym er a se â a n d HIV Rever se Tr a n scr ip ta se fr om
Sp on ge Hippospon gia sp .
Haruaki Ishiyama,1a Masami Ishibashi,1a Akio Ogawa,1b Shonen Yoshida,1b and
J un’ichi Kobayashi*,1a
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, J apan, and Laboratory of Cancer
Cell Biology, Research Institute for Disease Mechanism and Control, Nagoya University School of
Medicine, Nagoya 466, J apan
Received February 5, 1997X
Taurospongin A (1), a novel acetylene-containing natural product consisting of a taurine and two
fatty acid residues, has been isolated from the Okinawan marine sponge Hippospongia sp. and its
structure elucidated by spectral data and chemical means. Taurospongin A (1) exhibited potent
inhibitory activity against DNA polymerase â and HIV reverse transcriptase. The absolute
configurations of taurospongin A (1) were established to be 3R, 7S, and 9R by synthesis of the
MTPA ester of a degradation product of 1.
Ta ble 1. 1H a n d 13C NMR Da ta of Ta u r osp on gin A
Meth yl Ester (2) in C6D6
During our continuing studies on bioactive substances
from Okinawan marine organisms,2 we recently isolated
new sulfonosphingolipid, flavocristamides A and B, that
inhibit DNA polymerase R from a marine bacterium
Flavobacterium sp.3 Further investigations in search for
eukaryotic DNA replication enzyme inhibitors have now
resulted in isolation of a novel taurine-containing acety-
lenic lipid, taurospongin A (1), which remarkably inhibits
DNA polymerase â and HIV reverse transcriptase, from
the Okinawan marine sponge Hippospongia sp. This
paper describes the isolation and structure elucidation
of 1 including the determination of the absolute stereo-
chemistry based on the synthesis of a degradation
product of 1.
position
1Ha
J (Hz)
13Cb
HMBC (1H)
1
172.6
NH, 1′′, 2a, 2b
2a
2b
3
1.87 d
2.02 d
14.8
14.8
46.1
71.1
11
2a, 2b, 11
2a, 2b, 11
3-OH
4(2H)
5(2H)
6(2H)
7
4.31 br s
1.47 m
1.50 m
1.58 m
5.17 m
1.58 m
1.97 m
5.21 m
1.24 d
42.0
22.0
35.1
70.8
41.0
8a, 8b
8a, 8b, 9
9, 10
8a
8b
9
68.3
20.2
27.0
170.2
20.8
8a, 8b, 10
7,c 8a, 8b, 9
2a, 2b
13
10(3H)
11(3H)
12
6.8
1.18 s
The purple-colored sponge Hippospongia sp. collected
off Okinawa Island was extracted with MeOH, the
extract was partitioned between EtOAc and H2O, and the
aqueous phase was further extracted with n-BuOH.
While the EtOAc-soluble fraction was found to contain a
sesquiterpenoid quinone, metachromin A,4 as a major
constituent, the n-BuOH-soluble material was subjected
to silica gel flash column chromatography (CHCl3/MeOH,
4:1) followed by gel filtration on Sephadex LH-20 (CHCl3/
MeOH, 1:1) to give taurospongin A (1, 0.02% wet weight).
13(3H)
1′
2′(2H)
3′(2H)
4′
1.80 s
7,c 8b
171.3
34.5
15.2
79.0
80.9
19.6
27.3
131.3
128.4
27.7
2′, 3′, 9
3′
2′
2′, 3′, 6′
3′, 6′, 7′
7′
2.41 m
2.51 m
5′
6′(2H)
7′(2H)
8′
2.19 m
2.29 m
5.53 m
5.58 m
2.07 m
8′, 9′, 10′c
7′, 10′
6′,c 7′, 10′
8′, 9′
9′
10′(2H)
11′∼23′(26H) 1.25-1.64 m
29.7 ∼ 32.3
24′(2H)
25′(3H)
NH
1.37 m
0.96 t
23.1
25′
6.8
14.3
5.71 m
3.30 m
2.74 m
3.20 s
1′′(2H)
2′′(2H)
SO3Me(3H)
34.0
48.5
55.0
NH, 2′′
1′′
a
b
600 MHz. 125 MHz. c Correlation through four-bonds.
cm-1), acetylene (2370 cm-1), ester carbonyl (1740 cm-1),
The molecular formula of taurospongin A (1) was
revealed as C40H70NO9S by negative HRFABMS [m/ z
740.4819 (M - H)-, ∆ +4.8 mmu]. The IR absorptions
of 1 were suggestive of the presence of hydroxyl (3300
amide carbonyl (1640 cm-1), and sulfonic acid (1375 cm-1
)
functionalities. The methyl ester (2), prepared from 1
by treatment with diazomethane, was used for the 1H
and 13C NMR spectral studies (Table 1), which revealed
signals due to three ester or amide carbonyls, one
disubstituted double bond, one disubstituted triple bond,
one oxygenated quaternary sp3 carbon, two oxymethines,
one methoxy and four other methyl groups, and many
sp3 methylenes. Extensive 2D NMR spectral experi-
ments (1H-1H COSY, HOHAHA, HMQC, and HMBC5)
were carried out for 2 in C6D6 solution to suggest that 2
X Abstract published in Advance ACS Abstracts, May 15, 1997.
(1) (a) Hokkaido University. (b) Nagoya University.
(2) (a) Ishibashi, M.; Kobayashi, J . Heterocycles 1997, 44, 543-572.
(b) Kobayashi, J .; Ishibashi, M. Heterocycles 1996, 42, 943-970 and
references cited therein.
(3) Kobayashi, J .; Mikami, S.; Shigemori, H.; Takao, T.; Shimonishi,
Y.; Izuta, S.; Yoshida, S. Tetrahedron 1995, 51, 10487-10490.
(4) Ishibashi, M.; Ohizumi, Y.; Cheng, J .-F.; Nakamura, H.; Hirata,
Y.; Sasaki, T.; Kobayashi, J . J . Org. Chem. 1988, 53, 2855-2858.
S0022-3263(97)00206-5 CCC: $14.00 © 1997 American Chemical Society

3832 J . Org. Chem., Vol. 62, No. 12, 1997
Ishiyama et al.
consisted of three elements, i.e., a taurine, a trihydroxyl
fatty acid, and an unsaturated fatty acid, as described
below.
Amino acid analysis of the acid hydrolysate of 1
revealed the presence of taurine in 1. The methyl ester
2 was therefore inferred to be a methyl sulfonate ester
in the taurine moiety. The 1H NMR spectrum of 2
showed signals assignable to two methylene groups of
taurine and the H-1H COSY cross peaks were observed
1
Taurospongin A (1) contains three chiral centers at C-3,
C-7, and C-9. The relative stereochemistry of 1,3-diol at
the C-7/C-9 position was revealed to be syn by applying
Rychnovsky’s 13C-acetonide analysis9 for the acetonide
(5: δC 19.9, 30.3, and 98.4) prepared from 4. To elucidate
the relative stereochemistry between C-3 and the C-7/
C-9 position as well as the absolute stereochemistry of
these three chiral centers, two possible diastereomers 6
and 7, which correspond to the acetonide derivative 5,
for NH/H2-1′′ and H2-1′′/H2-2′′. The HMBC spectrum of
2 showed cross peaks due to 1H-13C long-range correla-
tions for NH/C-1 and H-1′′/C-1, thus indicating that the
taurine unit was connected to C-1 of trihydroxy fatty acid
through an amide bond.
For the trihydroxy fatty acid moiety of 2, a substruc-
ture from C-1 to C-4 with a tertiary methyl group on C-3
oxygenated carbon was suggested from the HMBC cor-
relations observed for H2-2/C-1, H2-2/C-3, H2-2/C-11, H2-
2/C-4, and H3-11/C-3. The 1H-1H COSY spectrum showed
the proton connectivities from H2-6 to H3-10. Acetyl and
unsaturated acyl groups were shown to be connected on
C-7 and C-9 oxymethines, respectively, through ester
linkages from the HMBC correlations of 2 for H-7/C-13
(via 4 bonds), H3-13/C-12, and H-9/C-1′. Thus, another
substructure for the C-6 to C-10 moiety was elucidated.
The C-4 and C-6 had to be connected through sp3
methylenes and the HOHAHA spectrum of 2 showed a
correlation between H2-4 and H-7. The number of
methylene carbons between C-4 and C-6, however, could
not be firmly determined because of overlapping of the
methylene signals.
were prepared as optically active forms as follows (Scheme
1). The methoxymethyl (MOM) ether (9) derived from
(R)-3-hydroxy-3-methyl-5-pentanolide (8)10 was reduced
with DIBAL to give a lactol, which was subjected to
Wittig reaction with (chloromethylene)triphenylphos-
phorane followed by protection with benzyloxymethyl
group to yield a 2:1 mixture of the E/ Z chlorovinyl
derivatives 10. On the other hand, (S)-3-[(tert-butyldim-
ethylsilyl)oxy]butanal ((S)-12) was prepared from methyl
(S)-(+)-3-hydroxybutylate ((S)-11)10 in two steps. The
1
As to the unsaturated fatty acid portion, the H-1H
COSY spectrum showed a cross peak for H2-3′/H2-6′ due
to long-range coupling through a triple bond. The
relatively high-field resonances of C-3′ (δC 15.2) and C-6′
(δC 19.6) implied that these methylenes were adjacent
1
to an acetylene group.6 The H-1H COSY revealed the
connectivities from H2-6′ to H2-10′ through an olefin at
C-8′/C-9′ as well as a cross peak for the terminal part,
H2-24′/H3-25′. The 8′Z-configration was deduced from the
13C chemical shifts of the allylic carbons [δC 27.3 (C-7′);
δC 27.7 (C-10′)].7 Though the C-10′ and C-24′ had to be
connected through sp3 methylene carbons, the number
of the methylenes between them was also unknown from
spectral data, thus requiring the following chemical
degradations.
lithium acetylide generated from E/ Z mixture of 10 (n-
BuLi, THF, 0 °C, 45 min) was coupled with the aldehyde
(S)-12 to afford a 1:1 mixture of the anti/ syn alcohols 13
and 14. The diastereomeric mixture was separable by
silica gel column chromatography, and each diastereomer
was then converted into its acetonide 15 and 16, respec-
tively. Relative stereochemistry of 1,3-diol moiety of 15
and 16 was elucidated from the 13C-acetonide analysis9
[15 (anti): δC 23.8, 29.0, 99.8; 16 (syn): δC 19.4, 30.1,
99.0]. Since the 1,3-diol moiety at C-7 and C-9 of
taurospongin A (1) was already revealed as syn, the syn
acetonide 16 was subjected to hydrogenation in the
presence of Raney Ni to furnish an alcohol 17. RuO4
oxidation11 of the alcohol 17 afforded an carboxylic acid,
which was coupled with taurine through an N-hydrox-
ysuccinimide ester.12 Passing through an ion exchange
chromatography (Amberlite IR-122) resulted in the depro-
tection of MOM ether and acetonide groups, and the
resulting sulfonic acid was treated with diazomethane
to give trihydroxy amide methyl ester 18, which was then
converted into acetonide 6. The diastereomeric syn
Methanolysis of 2 (MeOH/1 N HCl, 10:1)8 afforded two
fragments, unsaturated fatty acid methyl ester [3, EIMS
m/ z 390 (M+)] and trihydroxy amide [4, FABMS m/ z 356
(M + H)+]. Molecular weights of these methanolysis
products (3 and 4) clearly showed the lengths of the
methylene chains. The ∆8′-double bond was further
confirmed to be Z by the 1H coupling constant for 3 (J 8′,9′
11.3 Hz). From all of these data the gross structure of
)
taurospongin A was concluded as 1.
(5) The HMBC data were obtained by combination of three kinds of
HMBC spectra, i.e., conventional HMBC, field-gradient HMBC, and
D-HMBC (Furihata, K.; Seto, H. Tetrahedron Lett. 1995, 36, 2817-
2820).
(6) Kalinowski, H.-O.; Berger, S.; Braun, S. Carbon-13 NMR Spec-
troscopy; J ohn Wiley & Sons: Chichester, 1984; p 148.
(7) The allylic carbons of cis-double bonds are known to resonate
approximately at 27 ppm, while those of trans-ones at ca. 33 ppm:
Gunstone, F. D.; Pollard, M. R.; Scrimgeour, C. M.; Vedanayagam, H.
S. Chem. Phys. Lipids 1977, 18, 115-129.
(9) Rychnovsky, S. D.; Rogers, B.; Yang, G. J . Org. Chem. 1993, 58,
3511-3515.
(10) Chiral precursors 8, (S)-11, and (R)-11 were all commercially
available from Wako Pure Chemical, Ind., Ltd.
(11) Carlsen, P. H. J ; Katsuki, T; Martin, V. S; Sharpless, K. B. J .
Org. Chem. 1981, 46, 3936-3938.
(8) Costantino, V.; Fattorusso, E.; Mangoni, A. Liebigs Ann. 1995,
2133-2136.
(12) Paquet, A. Can. J . Chem. 1979, 57, 2775-2778.

Taurospongin A, Novel Acetylenic Fatty Acid Derivative
J . Org. Chem., Vol. 62, No. 12, 1997 3833
Sch em e 1a
lary by the methyl proton signals [19: δH 1.37 (H3-10)
and 1.11 (H3-11); 20: δH 1.22 (H3-10) and 1.17 (H3-11)].
The H NMR of bis-(S)-MTPA ester 21 from a natural
1
specimen proved to be completely identical with that of
synthetic bis-(R)-MTPA ester 19, implying that the
synthetic and natural samples (19 and 21, respectively)
are enantiomers.14 Thus the absolute configurations of
taurospongin A (1) were unambiguously established as
3R, 7S, and 9R.
Marine sponges of the genus Hippospongia often
elaborate various bioactive metabolites including ses-
quiterpenoid quinones,4,15 furanoterpenes,16 and secos-
terols.17 Taurospongin A (1) consisting of taurine, tri-
hydroxy fatty acid, and unsaturated fatty acid residues
appears to belong to an unprecedented class of marine
natural products, whereas taurine-bearing mono-fatty
acid derivatives were recently isolated from bivalve Pinna
muricata18 and protozoan Tetrahymena thermophila.19
The trihydroxy and unsaturated C25 fatty acid contained
in taurospongin A (1) are also new fatty acids, while a
C25 acetylenic fatty acid with more unsaturations was
recently isolated from Australian sponge Phakellia car-
dus.20 Acetylenic fatty acids mostly bearing bromine
atoms were frequently isolated from sponges of the
genera Petrosia21 and Xestspongia,22 and they were never
obtained so far from Hippospongia sp.
Taurospongin A (1) exhibited potent inhibitory activity
against DNA polymerase â and HIV reverse transcriptase
with IC50 values of 7.0 and 6.5 µM (Ki values of 1,7 and
1.3 µM), respectively.23 This inhibitory activity has been
frequently associated with the sulfonic acid function.3
Furthermore, 1 showed weak inhibitiory activity against
c-erbB-2 kinase (IC50 28 µg/mL), while there was no
cytotoxicity (IC50 > 10 µg/mL) against murine lymphoma
L1210 and human epidermoid carcinoma KB cells in
vitro.
acetonide 7 was also synthesized by coupling of the
acetylide from 10 with an enantiomeric aldehyde ((R)-
12), prepared from (R)-11,10 followed by the same reac-
tions as described above. The 1H NMR spectra of the
diastereomers 6 and 7 could be discriminated from each
other particulary by the AB quartet signals due to the
C-2 methylene protons (6: δH 2.28 and 2.41; 7: δH 2.29
and 2.40). The 1H NMR spectrum of the acetonide 5
obtained from natural specimen of taurospongin A (1)
was identical with that of the synthetic (3S,7R,9S)-
derivative 6. Thus, the relative configuration of 5 was
revealed as 3S*, 7R*, and 9S*. Synthetic sample 6,
however, unfortunately had very small optical rotation
([R]D +0.65°), thus implying that determination of the
absolute configurations of 5 based on the sign of the
optical rotation was not convincing. This problem could
be overcome by preparing Mosher’s acid esters13 from
synthetic and natural samples and distinguishing them
by NMR spectroscopy. The synthetic triol 18 was treated
with (S)- and (R)-MTPACl to give (R)- and (S)-bis MTPA
esters 19 and 20, respectively, while the triol 4 from
natural specimen was treated with (R)-MTPACl to give
bis-(S)-MTPA ester 21. The 1H NMR spectra of synthetic
Exp er im en ta l Section
Sp on ge Ma ter ia l. The sponge (Order Dictyoceratida,
Family Spongiidae, Hippospongia Schulze, 1879) was collected
off Okinawa Island and kept frozen until used. The specimen
was a massive, cavernous sponge. Skeleton consists of numer-
ous fine fibers forming a dense network. Primary fibers are
present superficially and are lightly cored. Primary fibers are
40 µm wide, and secondary fibers are 8-12 µm. There are no
spicules. The voucher specimen (SS-951) was deposited at
Faculty of Pharmaceutical Sciences, Hokkaido University.
Extr a ction a n d Isola tion . The sponge (0.91 kg, wet
weight) was extracted with MeOH (1.8 L and 0.7 L). After
evaporation under reduced pressure, the residue (91 g) was
(14) Coincidently, the signs of optical rotation of synthetic and
natural trihydroxy amides (18 and 4, respectively) were opposite (18:
[R]25 +5.7°; 4: [R]27 -10°).
D
D
(15) Luibrand, R. T.; Erdman, T. R.; Vollmer, J . J .; Scheuer, P. J .;
Finer, J .; Clardy, J . Tetrahedron 1979, 35, 609-612.
(16) Kobayashi, J .; Ohizumi, Y.; Nakamura, H.; Hirata, Y. Tetra-
hedron Lett. 1986, 27, 2113-2116.
(17) Madaio, A.; Piccialli, V.; Sica, D. Tetrahedron Lett. 1988, 29,
5999-6000.
(18) Chou, T.; Kuramoto, M.; Otani, Y.; Shinkai, M.; Yazawa, K.;
Uemura, D. Tetrahedron Lett. 1996, 37, 3871-3874.
(19) Kouda, K.; Ooi, T.; Kaya, K.; Kusumi, T. Tetrahedron Lett. 1996,
37, 6347-6350.
(20) Barrow, R. A.; Capon, R. J . Aust. J . Chem. 1994, 47, 1901-
1918.
(21) Fusetani, N.; Li, H.-Y.; Tamura, K.; Matsunaga, S. Tetrahedron,
1993, 49, 1203-1210 and references cited therein.
(22) Li, Y.; Ishibashi, M.; Sasaki, T.; Kobayashi, J . J . Chem. Res.
(S) 1995, 126-127 and references cited therein.
(23) Simbulan, C. M. G.; Taki, T.; Tamiya-Koizumi, K.; Suzuki, M.;
Savoysky, E.; Shoji, M.; Yoshida, S. Biochim. Biophys. Acta 1994, 1205,
68-74.
samples 19 and 20 were easily distinguishable particu-
(13) Dale, J . A.; Dull, D. L.; Mosher, H. S. J . Org. Chem. 1969, 34,
2543-2549.

3834 J . Org. Chem., Vol. 62, No. 12, 1997
Ishiyama et al.
partitioned between EtOAc (400 mL × 3) and 1 M NaCl (300
mL), and the aqueous portion was subsequently extracted with
n-BuOH (400 mL × 3). A portion (0.93 g) of the n-BuOH-
soluble material (7.1 g) was subjected to column chromatog-
raphy on silica gel (2.3 × 41 cm) with CHCl3/MeOH (80:20).
The fraction (47.7 mg) eluting from 240 to 350 mL was further
separated by Sephadex LH-20 column (2 × 120 cm) with
CHCl3/MeOH (1:1) to afford taurospongin A (1, 20 mg; 0.02%
wet weight).
1H NMR (CDCl3) δ 1.16 (3H, d, J ) 6.1 Hz), 1.23 (3H, s,), 1.39
(3H, s), 1.43 (3H, s), 2.28 (1H, d, J ) 14.8 Hz), 2.41 (1H, d, J
) 14.8 Hz), 3.33 (2H, t, J ) 5.8 Hz), 3.66 (1H, br s), 3.77 (2H,
m), 3.81 (1H, m), 3.93 (3H, s), 3.97 (1H, m), and 6.60 (1H, m);
13C NMR (CDCl3) δ 19.5, 19.9, 22.2, 26.8, 30.3, 33.8, 36.6, 38.7,
42.2, 46.5, 49.0, 55.6, 65.1, 68.9, 71.5, 98.4, and 172.6; FABMS
m/ z 396 (M + H)+; HRFABMS m/ z 396.2064 (M + H)+, calcd
for C17H34O7NS: 396.2060.
(R)-3-(Meth oxym eth oxy)-3-m eth yl-5-p en ta n olid e (9).
A solution of (3R)-mevalonolactone (8,10 5.31 g, 40.8 mmol) in
CH2Cl2-THF (1:1, 50 mL) was treated with N,N-diisopropy-
lethylamine (23.5 mL, 124 mmol), chloromethyl methyl ether
(7.1 mL, 95 mmol), and DMAP (999 mg, 8.16 mmol) at 60 °C
under an argon atmosphere for 12 h. After addition of 1 N
HCl (75 mL), the mixture was extracted with ethyl acetate
(150 mL × 5), dried over MgSO4, and concentrated in vacuo.
The residue was subjected to a silica gel colmun (hexane/
EtOAc, 1:1) to give the MOM ether (9, 6.03 g, 85%): colorless
oil; [R]30D -52.0° (c 1.37, CHCl3); IR νmax (neat) 2976 and 1736
NMR Sp ectr oscop y. NMR spectra were recorded at 500
or 600 MHz (1H) and 125 MHz (13C). The 1H and 13C NMR
chemical shifts were referenced to solvent signals at 7.20 and
128.0 ppm, respectively, for C6D6 or at 7.26 and 77.0 ppm,
respectively, for CDCl3. Multiplicities of 13C spectra were
assigned by DEPT experiments. For 2D NMR experiments,
standard pulse sequences and processing parameters were
employed and a total of 256 increments of 1k data points were
collected. The HOHAHA and HMQC spectra were in the
phase-sensitive mode, while the 1H-1H COSY and HMBC
spectra were in the magnitude mode. The HMQC and HMBC
1
cm-1; H NMR (CDCl3) δ 1.36 (3H, s), 1.86 (1H, ddd, J ) 5.5,
1
2,3
spectra were optimized for J C-H ) 140 Hz and
J
) 10
10.8 and 14.4 Hz), 2.02 (1H, m), 2.40 (1H, d, J ) 17.3 Hz),
2.88 (1H, dd, J ) 2.3 and 17.3 Hz), 3.35 (3H, s), 4.31 (1H, ddd,
J ) 3.6, 5.5 and 11.2 Hz), 4.55 (1H, dt, J ) 4.1 and 11.2 Hz),
4.68 (1H, d, J ) 7.6 Hz), and 4.75 (1H, d, J ) 7.6 Hz). Anal.
Calcd for C8H14O4: C, 55.16; H, 8.10. Found: C, 54.97; H, 8.00.
(S)-1-[(Ben zyloxy)m eth oxy]-6-ch lor o-3-[(m eth oxym e-
th yl)oxy]-3-m eth yl-5-h exen e (10). The lactone (9, 6.03 g,
34.6 mmol) was dissolved in dry Et2O (100 mL), and 0.93 M
DIBAL in hexane (40 mL, 37 mmol) was slowly added at -78
°C. The mixture was stirred at rt for 30 min, and then MeOH
(0.3 mL) was added. After addition of saturated Rochelle
solution (saturated potassium sodium tartrate aqueous solu-
tion, 50 mL), the whole was stirred for 1 h. Extraction with
EtOAc (100 mL × 5) followed by evaporation of the combined
organic solution under reduced pressure afforded a lactol (5.97
C-H
Hz, respectively.
Ta u r osp on gin A (1). Colorless amorphous solid; [R]27
D
+2.4° (c 0.20); IR νmax (film) 3320, 2920, 2850, 2370, 1740, 1640,
1240, and 1040 cm-1; H NMR (CDCl3) δ 0.87 (3H, t, J ) 6.9
1
Hz), 1.18 (3H, s), 2.04 (3H, s), 2.26 (1H, d, J ) 14.3 Hz), 2.35
(1H, d, J ) 14.3 Hz), 2.45 (4H, m), 3.02 (2H, m), 3.59 (2H, m),
4.94 (2H, m), 5.39 (2H, m), and 7.56 (1H, m); 13C NMR (CDCl3)
δ 14.1, 14.8, 20.0, 26.8, 34.3, 35.2, 47.1, 50.4, 68.4, 71.1, 127.8,
171.0, 171.6, and 172.3; FABMS (matrix: 3-nitrobenzyl alco-
hol) m/ z 740 (M - H)-; HRFABMS m/ z 740.4819 (M - H)-,
calcd for C40H70O9NS: 740.4771.
Ta u r osp on gin A Meth yl Ester (2). Taurospongin A (1,
10.6 mg, 14.3 µmol) was treated with a 0.6 M diazomethane
in Et2O (2 mL) at rt for 1 h. After evaporation of the solvent,
the residue was subjected to column chromatography on silica
gel (0.5 × 10 cm) with CHCl3/MeOH (10:1). The fraction (6.5
mg) eluting from 3 to 5 mL was further separated by Sephadex
LH-20 column (1.4 × 40 cm) with CHCl3/MeOH (1:1) to afford
taurospongin A methyl ester (2, 5.8 mg, 54%) together with
the starting sulfonic acid (1, 3.2 mg, 30%). 2: colorless oil;
g), which was used immediately without purification.
A
solution of the lactol (5.97 g) in dry THF (50 mL) was added
at -78 °C to a dark red solution of triphenyl(chloromethylene)-
phosphorane, which was prepared from (chloromethyl)triph-
enylphosphonium chloride (48.1 g, 139 mmol) in THF (100 mL)
and 1.67 M n-BuLi in pentane (83 mL, 139 mmol). The
mixture was stirred for 17 h at rt. After addition of a saturated
[R]27 -1.4° (c 0.78, CHCl3); IR νmax (film) 3370, 2920, 2860,
D
2360, 1730, 1650, 1250, and 1170 cm-1; 1H and 13C NMR (Table
1); FABMS (matrix: 3-nitrobenzyl alcohol) m/ z 778 (M + Na)+,
756 (M + H)+; HRFABMS m/ z 778.4958 (M + Na)+, calcd for
C41H73O9NSNa: 778.4904.
Cl aqueous solution (200 mL), the mixture was extracted
NH4
with EtOAc (400 mL × 3), washed with H2O and brine, dried
over MgSO4, and concentrated in vacuo. The residue was
purified with a silica gel column (hexane/EtOAc, 2:1) to yield
a chloroolefin as a 2:1 E/ Z mixture (22.2 g), part of which (17.8
g) was dissolved in dry CH2Cl2 (80 mL) and treated with N,N-
diisopropylethylamine (9.6 mL, 55 mmol) and benzyl chlorom-
ethyl ether (5.8 mL, 42 mmol) at rt for 22 h. After addition of
1 N HCl (40 mL), the mixture was extracted with Et2O (80
mL × 2), washed with H2O and brine, dried over MgSO4, and
concentrated in vacuo. The residue was subjected to a silica
gel colmun (hexane/EtOAc, 8:1) to give the (benzyloxy)methyl
Meth a n olysis of 2. Methyl ester (2, 4.9 mg, 6.6 µmol) was
dissolved in MeOH/1 N HCl (10:1, 1 mL) and heated at 80 °C
for 12 h in a sealed tube. The solvent was removed by a
nitrogen stream, and the residue dissolved in CHCl3-MeOH
(1:1, 1 mL) was treated with 0.6 M CH2N2 in Et2O (1 mL) at
rt for 1 h. After evaporation of the solvent, the residue was
purified on a silica gel column (0.5 × 5 cm) with 0-10% MeOH
in CHCl3 to give the unsaturated fatty acid methyl ester (3,
2.5 mg, 98%) and the trihydroxy amide (4, 0.8 mg, 35%). 3:
Colorless amorphous solid; IR νmax (film) 2920, 2360, and 1740
ether (10, 8.01 g, 84%): colorless oil; [R]23 -1.7° (c 0.84,
D
1
CHCl3); IR νmax (neat) 1456 and 1037 cm-1; H NMR (CDCl3,
1
cm-1; H NMR (CDCl3) δ 0.88 (3H, t, J ) 6.8 Hz), 2.02 (2H,
*: signals for minor isomer) δ 1.23 (3H, s), 1.27 (3H*, s), 2.30
(2H, dd, J ) 6.1 and 2.2 Hz), 2.50 (2H*, br d, J ) 7.2 Hz), 3.36
(3H, s), 3.38 (3H*, s), 3.68 (2H, m), 4.60 (2H, s), 4.61 (2H*, s),
4.74 (2H, s), 4.75 (2H*, s), 5.86-6.00 (2H, m), 6.13 (1H*, br d,
J ) 7.1 Hz), and 7.28-7.35 (5H, m). Anal. Calcd for C8H14O4-
Cl: C, 62.09; H, 7.66; Cl, 10.78. Found: C, 62.02; H, 7.60; Cl,
10.80.
m), 2.17 (2H, m), 2.20 (2H, m), 2.47 (2H, m), 2.52 (2H, m),
3.69 (3H, s), 5.38 (1H, dt, J ) 11.3 and 6.6 Hz), and 5.43 (1H,
dt, J ) 11.3 and 6.8 Hz); EIMS m/ z 390 (M+); HREIMS m/ z
390.3517, calcd for C26H46O2 (M+): 390.3498. 4: Colorless oil;
[R]27 -10° (c 0.08, CHCl3); IR νmax (neat) 3360, 2930, 1650,
D
1350, 1160, and 990 cm-1; 1H NMR (CDCl3) δ 1.21 (3H, d J )
6.1 Hz), 1.24 (3H, s), 2.29 (1H, d, J ) 14.6 Hz), 2.45 (1H, d, J
) 14.6 Hz), 3.35 (2H, t, J ) 5.8 Hz), 3.76 (2H, m), 3.89 (1H,
m), 3.93 (3H, s), 4.06 (1H, m), and 6.62 (1H, m); EIMS m/ z
319 (M - 2H2O)+; FABMS (matrix: glycerol) m/ z 356 (M +
H)+; HRFABMS m/ z 356.1753 (M + H)+, calcd for C14H30O7-
NS: 356.1742.
(S)-3-(ter t-Bu tyld im eth ylsiloxy)bu ta n a l ((S)-12). The
methyl ester ((S)-11,10 4.28 g, 36.3 mmol) dissolved in dry CH2-
Cl2 (25 mL) was treated with tert-butyldimethylsilyl chloride
(TBSCl, 8.2 g, 54 mmol) and imidazole (4.9 g, 73 mmol) at rt
for 14 h. After addition of saturated NH4Cl aqueous solution
(50 mL), the mixture was extracted with Et2O (100 mL × 3),
washed with H2O and brine, dried over MgSO4, and concen-
trated in vacuo. Purification with a silica gel column (hexane/
EtOAc, 25:1) gave methyl (S)-3-(tert-butyldimethylsiloxy)-
Aceton id e 5. The trihydroxy amide (4, 0.7 mg, 2 µmol) was
treated with dimethoxypropane (DMP, 0.25 mL, 2 mmol) and
pyridinium p-toluenesulfonate (PPTS, 3.8 mg, 15.2 µmol) in
dry CH2Cl2 (1 mL) at rt for 28 h. After evaporation of the
solvent, separation with silica gel column (0.5 × 10 cm; CHCl3/
MeOH, 95:5) afforded the acetonide (5, 0.6 mg, 77%): colorless
butyrate (7.2 g, 85%): colorless oil; [R]27 +27.3° (c 1.13,
D
1
CHCl3); IR νmax (neat) 1743 and 1085 cm-1; H NMR (CDCl3)
δ 0.04 (3H, s), 0.06 (3H, s), 0.86 (9H, s), 1.19 (3H, d, J ) 6.2),
2.37 (1H, dd, J ) 5.3 and 14.5 Hz), 2.48 (1H, dd, J ) 7.7 and
oil; IR νmax (neat) 3320, 2930, 1650, 1360, 1170, and 990 cm-1
;

Taurospongin A, Novel Acetylenic Fatty Acid Derivative
J . Org. Chem., Vol. 62, No. 12, 1997 3835
14.5 Hz), 3.66 (3H, s), and 4.28 (1H, ddq, J ) 5.3, 7.7 and 6.2
Hz). Anal. Calcd for C11H24O3Si: C, 56.85; H, 10.41. Found:
C, 56.73; H, 10.29. The silyl ether (6.4 g, 27.6 mmol) was
dissolved in dry toluene (90 mL), and 1.01 M DIBAL in toluene
(27 mL, 28 mmol) was slowly added to the solution at -78 °C.
The mixture was stirred at -78 °C for 10 min. After addition
of saturated NH4Cl aqueous solution (9 mL), the mixture was
stirred at rt for 1 h. To the mixture was added Et2O (200 mL),
and stirring was continued for 1.5 h at rt. After addition of
MgSO4, the solution was filtered through Celite, washed with
Et2O, and evaporated under reduced pressure to give the
39.4, 55.4, 60.4, 63.8, 64.7, 69.3, 76.5, 81.2, 81.4, 91.1, 94.6,
99.0, 127.6, 127.8, 128.4, and 137.9. Anal. Calcd for
C24H36O6: C, 68.55; H, 8.63. Found: C, 68.28; H, 8.62. The
anti-acetonide 15 was prepared from the anti-alcohol 13 by
the same procedure as above. 15: colorless oil; [R]21D -0.5° (c
0.89, CHCl3); IR νmax (neat) 2245 and 1037 cm-1 1H NMR
;
(CDCl3) δ δ 1.19 (3H, d, J ) 6.2 Hz), 1.35 (3H, s), 1.36 (3H, s),
1.61 (3H, s), 1.95 (1H, dt, J ) 14.2 and 7.1 Hz), 2.02 (1H, dt,
J ) 14.2 and 7.1 Hz), 2.52 (2H, d, J ) 2.1 Hz), 3.37 (3H, s),
3.72 (2H, t, J ) 7.1 Hz), 4.20 (1H, m), 4.60 (2H, s), 4.71 (1H,
d, J ) 7.5 Hz). 4.73 (1H, d, J ) 7.5 Hz), 4.74 (1H, m), 4.75
(2H, s), and 7.27-7.36 (5H, m); 13C NMR (CDCl3) δ 21.7, 23.6,
23.8, 29.0, 30.9, 38.6, 38.7, 55.5, 59.8, 61.9, 63.8, 69.3, 76.6,
82.4, 82.8, 91.2, 94.6, 99.8, 127.7, 127.8, 128.4, and 137.9;
FDMS m/ z 405 (M - CH3)+; HRFDMS m/ z 405.2304 (M -
CH3)+, calcd for C23H33O6: 405.2277.
1
aldehyde [(S)-12, 5.5 g; H NMR (CDCl3) δ 0.06 (3H, s), 0.08
(3H, s), 0.87 (9H, s), 1.24 (3H, d, J ) 6.2), 2.47 (1H, ddd, J )
1.9, 4.9, and 15.7 Hz), 2.55 (1H, ddd, J ) 2.8, 7.0 and 15.7
Hz), 4.35 (1H, ddd, J ) 4.9, 6.2, and 7.0 Hz), and 9.80 (1H,
dd, J ) 1.9 and 2.8 Hz)], which was used immediately without
purification.
(3S,7R,9S)-7,9-O-Isop r op ylid en e-3-(m eth oxym eth oxy)-
3-m eth yld eca n e-1,7,9-tr iol. (17). A solution of the syn-
acetonide (16, 629 mg, 1.5 mmol) in ethanol (6 mL) was stirred
under a hydrogen atmosphere in the presence of 0.84 g of
Raney Ni (W-2) at rt for 16 h. Insoluble material was removed
by filtration through Celite, and the filtrate was concentrated
in vacuo. The residue was purified on a silica gel column
(hexane/EtOAc, 1:1) to afford the alcohol (17, 306 mg, 67%):
(3S,7R,9S)- a n d (3S,7S,9S)-1-[(Ben zyloxy)m eth oxy]-9-
(ter t-bu tyld im eth ylsiloxy)-3-(m eth oxym eth oxy)-3-m eth -
yl-5-d ecyn -7-ol (13 a n d 14). To a solution of chloroolefin (10,
3.8 g, 12 mmol) in THF (45 mL) was added 1.67 M n-BuLi in
pentane (21 mL, 35 mmol) at -78°C. To this mixture was
added a solution of the aldehyde ((S)-12, 5.5 g) in THF (55
mL) at -78°C and stirred for 1 h at -78 °C. After addition of
saturated NH4Cl aqueous solution (150 mL), the mixture was
extracted with EtOAc (300 × 3 mL), washed with H2O and
brine, dried over MgSO4, and evaporated under reduced
pressure. The residue was purified on a silica gel column
(hexane/EtOAc, 6:1) to give two diastereomeric acetylenic
alcohols [13 (anti), 1.54 g, 27% and 14 (syn), 1.89 g, 33%]. 13:
colorless oil; [R]21D +24.2° (c 1.05, CHCl3); IR νmax (neat) 3447,
colorless oil; [R]25 +14.5° (c 1.04, CHCl3); IR νmax (neat) 3446
D
1
and 1037 cm-1; H NMR (CDCl3) δ 1.16 (3H, d, J ) 6.0 Hz),
1.26, (3H, s), 1.39 (3H, s), 1.43 (3H, s), 1.70 (1H, ddd, J ) 14.6,
6.3, and 5.4 Hz), 1.87 (1H, ddd, J ) 14.6, 7.1, and 5.5 Hz),
2.67 (1H, br m), 3.37 (3H, s), 3.79 (3H, m), 3.96 (1H, ddq, J )
12.0, 2.5, and 6.0 Hz), 4.70 (1H, d, J ) 7.8 Hz), and 4.71 (1H,
d, J ) 7.8 Hz); 13C NMR (CDCl3) δ 19.3, 19.8, 22.2, 23.7, 30.2,
36.6, 38.7, 39.1, 40.8, 55.4, 59.2, 65.0, 68.5, 79.3, 90.6, and 98.3.
Anal. Calcd for C16H32O5: C, 63.13; H, 10.59. Found: C,
63.00; H, 10.61.
2234, and 1038 cm-1 1H NMR (CDCl3) δ 0.09 (3H, s), 0.11
;
(3H, s), 0.89 (9H, s), 1.19 (3H, d, J ) 6.2), 1.35 (3H, s), 1.78
(1H, m), 1.82 (1H, m), 1.95 (1H, dt, J ) 14.2 and 7.1 Hz), 2.03
(1H, dt, J ) 14.2 and 7.1 Hz), 2.49 (1H, d, J ) 16.3 Hz), 2.52
(1H, d, J ) 16.3 Hz), 3.22 (1H, br d, 5.2 Hz), 3.37 (3H, s), 3.72
(2H, t, J ) 7.1 Hz), 4.24 (1H, m), 4.60 (1H, br m), 4.61 (2H, s),
4.72 (1H, d, J ) 7.5 Hz), 4.74 (1H, d, J ) 7.5 Hz), 4.75 (2H, s),
and 7.28-7.37 (5H, m); FDMS m/ z 495 (M + H)+; HRFDMS
m/ z 495.3171 (M + H)+, calcd for C27H47O6Si: 495.3142. 14:
colorless oil; [R]31D +22.8° (c 1.13, CHCl3); IR νmax (neat) 3447,
Met h yl
2-(((3S,7R,9S)-3-Met h yl-3,7,9-t r ih yd r oxyd e-
ca n oyl)a m in o)eth a n esu lfon a te (18). To a solution of al-
cohol (17, 229 mg, 0.753 mmol) in CCl4 (2 mL), MeCN (2 mL),
and phosphate buffer (pH 7, 3 mL) were added NaIO4 (669
mg, 3.09 mmol) and RuCl3‚nH2O (10 mg) at rt. After stirring
at rt for 1 h, H2O (4 mL) was added, and the aqueous phase
was extracted with Et2O (20 mL × 3), washed with H2O and
saturated NaCl, dried over MgSO4, and evaporated in vacuo
to give a carboxylic acid, which was used immediately without
purification. A solution of the carboxylic acid in dioxane (2
mL) was treated with N-hydroxysuccinimide (123 mg, 1.07
mmol) and DCC (175 mg, 0.91 mmol) at rt for 2 h. After
removal of the precipitates by filtration, the filtrate was
evaporated under reduced pressure to give the N-hydroxysuc-
cinimide ester, which was treated with taurine (131 mg, 0.945
mmol) and triethylamine (0.2 mL, 1.4 mmol) in dioxane (2.5
mL) and H2O (2.5 mL) at rt for 30 min. The mixture was
evaporated and extracted with CHCl3. The CHCl3-soluble
material was subjected to ion exchange column chromatogra-
phy (Amberlite IR-122, CHCl3/MeOH, 1:1) to give a sulfonic
acid, which was treated with 0.6 M CH2N2 in Et2O at rt.
Purification by silica gel column chromatography (CHCl3/
MeOH, 9:1) gave the trihydroxy amide (18, 64 mg, 24%):
2223, and 1038 cm-1 1H NMR (CDCl3) δ 0.08 (3H, s), 0.08
;
(3H, s), 0.88 (9H, s), 1.18 (3H, d, J ) 6.1), 1.34 (3H, s), 1.73
(1H, ddd, J ) 3.7, 6.0 and 13.7 Hz), 1.89 (1H, ddd, J ) 7.5, 9.1
and 13.7 Hz), 1.95 (1H, dt, J ) 14.4 and 7.2 Hz), 2.03 (1H, dt,
J ) 14.4 and 7.2 Hz), 2.49 (1H, dd, J ) 1.8 and 17.1 Hz), 2.52
(1H, dd, J ) 1.8 and 17.1 Hz), 2.82 (1H, br d), 3.37 (3H, s),
3.72 (2H, t, J ) 7.2 Hz), 4.04 (1H, m), 4.50 (1H, br m), 4.60
(2H, s). 4.71 (1H, d, J ) 7.5 Hz), 4.74 (1H, d, J ) 7.5 Hz),
4.75 (2H, s), and 7.27-7.36 (5H, m). Anal. Calcd for C27H46O6-
Si: C, 65.55; H, 9.37. Found: C, 65.52; H, 9.41.
(3S,7R,9S)- a n d (3S,7S,9S)-1-[(Ben zyloxy)m eth oxy]-7,9-
O-isopr opyliden e-3-(m eth oxym eth oxy)-3-m eth yl-5-decyn e-
7,9-d iol (15 a n d 16). The syn-alcohol (14, 1.8 g, 3.6 mmol)
in THF (20 mL) was treated with 1.0 M tetra-n-butylammo-
nium fluoride (TBAF) in THF (7 mL, 7 mmol) at rt for 2.5 h.
After addition of saturated NH4Cl aqueous solution (75 mL),
the mixture was extracted with EtOAc (200 × 3 mL), washed
with brine, dried over MgSO4, and evaporated under reduced
pressure to give a crude diol, which was dissolved in CH2Cl2
(20 mL) and treated with DMP (5 mL, 40 mmol) and PPTS
(305 mg, 1.22 mmol) at rt for 16 h. After addition of saturated
NaHCO3 aqueous solution (50 mL), the reaction mixture was
extracted with Et2O (100 mL × 3), washed with H2O and brine,
dried over MgSO4, and evaporated under reduced pressure to
give a residue, which was purified on a silica gel column
(hexane/EtOAc, 4:1) to give the syn-acetonide (16, 1.4 g,
92%): colorless oil; [R]23D -16.5° (c 0.47, CHCl3); IR νmax (neat)
colorless oil; [R]25 +5.7° (c 0.6, CHCl3); FABMS m/ z 356 (M
D
+ H)+; HRFDMS m/ z 356.1738 (M + H)+, calcd for C14H30O7-
1
NS: 356.1743; IR, H NMR, and FABMS spectra were identi-
cal with those of 4.
Meth yl 2-(((3S,7R,9S)-7,9-O-Isop r op ylid en e-3-m eth yl-
3,7,9-tr ih yd r oxyd eca n oyl)a m in o)eth a n esu lfon a te (6). A
solution of triol (18, 31.4 mg, 88.3 µmol) in CH2Cl2 (1.5 mL)
was treated with DMP (0.5 mL) and PPTS (7 mg, 28 µmol) at
rt for 2 h. After addition of saturated NaHCO3 aqueous
solution (2 mL), the reaction mixture was extracted with
EtOAc (4 mL × 3), washed with H2O and brine, dried over
MgSO4, and evaporated under reduced pressure to give a
residue, which was purifid on a silica gel column (CHCl3/
MeOH, 95:5) to give the acetonide (6, 22.7 mg, 62%): colorless
1
2234 and 1038 cm-1; H NMR (CDCl3) δ 1.16 (3H, d, J ) 6.1
Hz), 1.34 (3H, s), 1.43 (3H, s), 1.44 (3H, s), 1.93 (1H, dt, J )
14.2 and 7.2 Hz), 2.02 (1H, dt, J ) 14.2 and 7.2 Hz), 2.50 (1H,
dd, J ) 1.8 and 12.7 Hz), 2.53 (1H, dd, J ) 1.8 and 12.7 Hz),
3.36 (3H, s), 3.72 (2H, t, J ) 7.2 Hz), 3.95 (1H, ddq, J ) 2.6,
11.6 and 6.1 Hz), 4.61 (2H, s), 4.64 (1H, m), 4.71 (1H, d, J )
7.6 Hz). 4.73 (1H, d, J ) 7.6 Hz), 4.75 (2H, s), and 7.27-7.35
(5H, m); 13C NMR (CDCl3) δ 19.4, 21.8, 23.7, 30.1, 30.9, 38.6,
oil; [R]28 +0.65° (c 1.23, CHCl3); FDMS m/ z 396 (M + H)+;
D
HRFDMS m/ z 396.2088 (M + H)+, calcd for C17H34O7NS:
396.2060; IR, 1H and 13C NMR, and FABMS spectra were
identical with those of 5.

3836 J . Org. Chem., Vol. 62, No. 12, 1997
Ishiyama et al.
Meth yl 2-(((3S,7S,9R)-7,9-O-Isop r op ylid en e-3-m eth yl-
3,7,9-tr ih ydr oxydecan oyl)am in o)eth an esu lfon ate (7). The
diastereomeric syn acetonide 7 was synthesized by the same
procedures as above starting with the coupling of the acetylide
derived from 10 with the enantiomeric aldehyde ((R)-12),
prepared from (R)-1110 (see Supporting Information). 7:
chloride by the same procedures for 21 to afford (R)- and (S)-
bis-MTPA esters 19 and 20, respectively. 19: FABMS m/ z
788 (M + H)+; HRFABMS m/ z 788.2529 (M + H)+, calcd for
1
C
34H44O11NSF6: 788.2539; IR, H NMR, and FABMS spectra
were identical with those of 21. 20: colorless oil; IR νmax (neat)
1
3328, 2928, 1743, 1626, 1360, 1168, and 990 cm-1; H NMR
colorless oil; [R]23 -8.2° (c 0.70, CHCl3); IR νmax (neat) 3318,
D
(CDCl3) δ 1.17 (3H, s), 1.22 (3H, d, J ) 6.3 Hz), 1.79 (1H, dt,
J ) 14.1 and 6.3 Hz), 2.06 (1H, dt, J ) 14.1 and 6.9 Hz), 2.23
(1H, d, J ) 14.8 Hz), 2.30 (1H, d, J ) 14.8 Hz), 3.33 (2H, m),
3.53 (3H, s), 3.54 (3H, s), 3.74 (2H, m), 3.92 (3H, s), 5.06 (1H,
m), 5.13 (1H, m), 6.44 (1H, m), 7.41 (6H, m), 7.50 (2H, m),
and 7.53 (2H, m); FABMS m/ z 788 (M + H)+; HRFABMS m/ z
788.2568 (M + H)+, calcd for C34H44O11NSF6: 788.2539.
2941, 1651, 1359, 1164, and 990 cm-1; 1H NMR (CDCl3) δ 1.16
(3H, d, J ) 6.0 Hz), 1.23 (3H, s), 1.39 (3H, s), 1.44 (3H, s),
2.29 (1H, d, J ) 14.7 Hz), 2.40 (1H, d, J ) 14.7 Hz), 3.34 (2H,
t, J ) 5.8 Hz), 3.69 (1H, br s), 3.77 (2H, m), 3.82 (1H, m), 3.93
(3H, s), 3.97 (1H, m), and 6.59 (1H, m); 13C NMR (CDCl3) δ
19.5, 19.9, 22.2, 26.6, 30.3, 33.9, 36.6, 38.8, 42.2, 46.6, 49.0,
55.6, 65.1, 68.8, 71.5, 98.4, and 172.6; FABMS m/ z 396 (M +
H)+; FDMS m/ z 396 (M + H)+; HRFDMS m/ z 396.2089 (M +
H)+, calcd for C17H34O7NS: 396.2060.
Ack n ow led gm en t. We thank Mr. Z. Nagahama for
his help in collecting the sponge, and Dr. J . Fromont,
J ames Cook University, for identification of the sponge.
We are also grateful to Prof. T. Sasaki, Kanazawa
University, for cytotoxic tests, and to Banyu Pharma-
ceutical Co. Ltd., for kinase assay. This work was partly
supported by a Grant-in-Aid from the Naito Foundation
and a Grant-in-Aid for Scientific Research from the
Ministry of Education, Science, Sports, and Culture of
J apan. H.I. thanks Research Fellowships of the J apan
Society for the Promotion of Science for Young Scien-
tists.
Bis-(S)-MTP A Ester 21. A solution of the natural speci-
men-derived triol (4, 2.6 mg, 7.3 µmol) in CH2Cl2 (40 µmol)
was treated with (R)-MTPA chloride (7.7 µL, 41.8 µmol) in the
presence of DMAP (69 µg, 0.56 µmol) and triethylamine (4.2
µL, 29.4 mmol) at rt for 18 h. After addition of 3-(dimethy-
lamino)propylamine (5 µL, 39 µmol) and evaporation under
reduced pressure, the residue was applied on an ion exchange
chromatography (Amberlite IR-122, MeOH). The effluent
contained the corresponding sulfonic acid, which was treated
with 0.6 M CH2N2 in Et2O and purified by silica gel column
chromatography (CHCl3/MeOH, 98:2) to give the bis-(S)-MTPA
ester (21, 0.8 mg, 14%): colorless oil; IR νmax (neat) 3396, 2952,
1744, 1654, 1356, 1167, and 991 cm-1; 1H NMR (CDCl3) δ 1.11
(3H, s), 1.37 (3H, d, J ) 6.3 Hz), 1.77 (1H, dt, J ) 14.1 and 6.4
Hz), 2.07 (1H, dt, J ) 14.1 and 6.9 Hz), 2.18 (1H, d, J ) 14.8
Hz), 2.27 (1H, d, J ) 14.8 Hz), 3.34 (2H, m), 3.54 (6H, s, MeO),
3.76 (2H, m), 3.92 (3H, s), 5.05 (1H, m), 5.15 (1H, m), 6.50
(1H, m), 7.41 (6H, m), and 7.52 (4H, m); FABMS m/ z 788 (M
+ H)+; HRFABMS m/ z 788.2540 (M + H)+, calcd for
C34H44O11NSF6: 788.2539.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra including 2D NMR spectra of 2 and experimental data
for preparation of 7 (14 pages). This material is contained in
libraries on microfiche, immediately follows this article in the
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(R)- a n d (S)-Bis-MTP A Ester s 19 a n d 20. The synthetic
triol 18 was treated separately with (S)- and (R)-MTPA
J O970206R