Improved syntheses of morinol C and D by employing mizoroki-heck reaction and their cytotoxic and antimicrobial activities

Article abstract of DOI:10.1271/bbb.100255

Improved syntheses of optically pure (-)- and (+)- morinol C, and (-)- and (+)-morinol D were achieved by employing the Mizoroki-Heck reaction to construct the cinnamyl moiety. The protective group of the alkene substrate affected the yield of this key re

Full text of DOI:10.1271/bbb.100255

Biosci. Biotechnol. Biochem., 74 (8), 1641–1644, 2010
Improved Syntheses of Morinol C and D by Employing Mizoroki-Heck Reaction
and Their Cytotoxic and Antimicrobial Activities
Koji OGURA,1 Takuya SUGAHARA,1;2 Masafumi MARUYAMA,1
y
1;2;
Koichi AKIYAMA,3 and Satoshi YAMAUCHI
1Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
2South Ehime Fisheries Research Center, 1289-1 Funakoshi, Ainan, Ehime 798-4292, Japan
3Integrated Center for Sciences, Tarumi Station, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
Received April 7, 2010; Accepted May 17, 2010; Online Publication, August 7, 2010
[doi:10.1271/bbb.100255]
Improved syntheses of optically pure (ꢀ)- and (þ)-
morinol C, and (ꢀ)- and (þ)-morinol D were achieved
by employing the Mizoroki-Heck reaction to construct
the cinnamyl moiety. The protective group of the alkene
substrate affected the yield of this key reaction. The
reaction with a combination of the acetate-protected
olefin and 4-methoxyphenylboronic acid gave the best
result producing morinol C and D. All stereoisomers of
morinol C and D showed cytotoxic activity, with (R,R)-
morinol C showing the highest antibacterial activity.
(97% yield) of trans olefin 10 was observed, when
4-methoxyphenylboronic acid, Cu(OAc)2, LiOAc, and
Pd(OAc)2 in DMF6) were used with acetate substrate 7
(entry 2). The concentration of the substrate between
1 mM and 5 mM did not affect the yield. The reaction
with pivalate 6 under the same condition gave 9 in 76%
yield (entry 1), while the reaction with triisopropylsilyl
ether 8 gave 11 in only 32% yield (entry 6). The other
reaction conditions for alkene coupling using the
protective substrates are shown in the table. The best
substrates for the Mizoroki-Heck reaction were 4-
methoxyphenylboronic acid and acetate. The hydrolysis
of coupling compound 10 gave 1 in 83% yield.
Compound 2 was obtained from an enantiomer of 7
and compounds 3 and 4 were respectively obtained from
the diastereomeric acetate 1211) and its enantiomer
(Scheme 1). The enantiomeric excess was determined to
be more than 99% by HPLC with a chiral column.
This study enable us to improve the synthetic route to
morinol C and D by employing the Mizoroki-Heck reac-
tion through four steps to give 46%–63% overall yields.
Key words: morinol C and D; neolignan; Mizoroki-
Heck reaction
Morinol C (1 and 2) and D (3 and 4) (Fig. 1) were
isolated from Morina chinensis as an enantiomeric
mixtures.1) Although this plant source has been used as
a traditional Chinese medicine, the effect of 1–4 has not
been elucidated. These compounds have a characteristic
phenylpropanoid bonding system. Since many biological
activities of the phenylpropanoid compounds have been
reported,2,3) biological research into 1–4 is an interesting
subject. The development of an effective method for
synthesizing optically pure compounds is important to
pursue into the biological activity of these compounds.
Our previous study of the first syntheses of 1–44)
employed the Horner-Wadsworth-Emmons reaction to
furnish the cinnamyl moiety, giving 1–4 by 7–11 steps in
5–9% overall yields. A more effective synthetic method
by employing the Mizoroki-Heck reaction to construct
the cinnamyl structure is described in this article. The
antimicrobial and cytotoxic activities are also discussed.
Biological activity
Synthesized stereoisomers 1–4 were evaluated by a
WTS-8 assay for their cytotoxic activity toward U266
cells. All compounds showed almost same level of
cytotoxic activity at 30 mmol (Fig. 2). A cytotoxic
activity test of the ꢀ-butyrolactone type of lignan,
(ꢀ)-arctigenin,2) has shown a decrease in living cells to
30% at 30 mmol. It was found that the stereochemistry
of morinol C and D had no affect on the cytotoxic
activity. The antibacterial activity was also evaluated
(Table 2). Two gram-positive bacteria (B. subtillus and
L. denitrificans) and one gram-negative bacterium
(S. choleraesuis) were sensitive to these compounds.
Stereoisomer 2 in particular showed the highest activity,
giving an MIC value of 6.3 mM against S. choleraesuis.
This activity is weaker than that of the butane type of
lignan, (þ)-guaiaretic acid2) (MIC of 3.1 mM) and the
antibiotic, valinomycin (MIC of 6.5 mM). Although some
lignans have shown antifungal activity,12–14) no anti-
fungal activity of 1–4 against phytopathogenic fungi was
apparent. The biological activities of all the stereo-
isomers of 1–4, which are new neolignans, were
examined for the first time in this study.
Results and Discussion
Syntheses of morinol C and D
The optimum conditions for the Mizoroki-Heck
reaction of 5–8 were examined to achieve an efficient
synthesis of 1. Substrates 5–8 were prepared by the
reported method with a small modification.4) The
reaction with diol 5 has not so far given the coupling
compounds under the conditions we examined.5–10) We
checked the effect of the protective groups by selecting
pivaloyl ester 6, acetate 7, and silyl ether 8 as the
substrates. Table 1 shows the results. The highest yield
y
To whom correspondence should be addressed. Tel: +81-89-946-9846; Fax: +81-89-977-4364; E-mail: syamauch@agr.ehime-u.ac.jp

1642
K. OGURA et al.
Table 1. Coupling Reaction Using Substrates 6–8
OR
OR
OCH3
OCH3
OCH3
OCH3
RO
RO
Table
MeO
X
9: R = Piv
10: R = Ac
11: R = TIPS
5: R = H, 6: R = Piv
7: R = Ac, 8: R = TIPS
OCH3
Temperature Time
(ꢁC)
Product
(Yield, %)
Entry Substrate
X
Reagents
Cu(OAc)2, LiOAc, Pd(OAc)2/DMF
(h)
1
2
6
7
7
7
7
7
8
6
7
8
6
7
8
6
7
7
8
8
B(OH)2
100
100
100
100
80
2
2
9 (76)
B(OH)2 (1.2 eq.) Cu(OAc)2 (2.0 eq.), LiOAc (3.0 eq.), Pd(OAc)2 (0.1 eq.)/DMF
B(OH)2 (1.2 eq.) Cu(OAc)2 (2.0 eq.), LiOAc (3.0 eq.), Pd(OAc)2 (0.01 eq.)/DMF
B(OH)2 (1.2 eq.) Cu(OAc)2 (1.0 eq.), LiOAc (1.5 eq.), Pd(OAc)2 (0.1 eq.)/DMF
B(OH)2 (1.2 eq.) Cu(OAc)2 (2.0 eq.), LiOAc (3.0 eq.), Pd(OAc)2 (0.1 eq.)/DMF
B(OH)2 (1.2 eq.) Cu(OAc)2 (2.0 eq.), LiOAc (3.0 eq.), Pd(OAc)2 (0.1 eq.)/DMF
10 (97)
10 (78)
10 (93)
10 (64)
10 (52)
11 (32)
3
2
3
2
4
2
5
60
2
6
B(OH)2
I
Cu(OAc)2, LiOAc, Pd(OAc)2/DMF
Pd(OAc)2/CH3CN
Pd(OAc)2/CH3CN
100
80
2
16
7
9 (0)
8
I
80
80
16 10 (21)
16 11 (11, Z isomer, 6)
9
I
Br
Pd(OAc)2/CH3CN
10
11
12
13
14
15
16
17
PdCl2(PPh3)2, Et3N/DMF
PdCl2(PPh3)2, Et3N/DMF
PdCl2(PPh3)2, Et3N/DMF
2nd Grubbs/CH2Cl2
90
90
4
4
4
9
7
7
7
7
9 (0)
Br
Br
10 (7)
11 (0)
9 (30)
90
40
CH=CH2
CH=CH2
CH=CH2
CH=CH2
CH=CH2
2nd Grubbs/CH2Cl2
40
40
10 (34)
10 (40)
11 (0)
11 (25)
2nd Grubbs/toluene
2nd Grubbs/CH2Cl2
40
40
2nd Grubbs/toluene
WST-8 Assay
OH
9
8
OCH3
OCH3
0.090
0.080
0.070
0.060
0.050
0.040
0.030
0.020
0.010
0.000
7
HO
9'
8'
7'
OCH3
(7S,8S)-Morinol C (1)
(7R,8R)-Morinol C (2)
(7S,8R)-Morinol D (3)
(7R,8S)-Morinol D (4)
1
2
3
4
Control
Fig. 1. (7S,8S)- and (7R,8R)-Morinol C and (7S,8R)- and (7R,8S)-
Morinol D.
Fig. 2. Cytotoxic Activity of 1–4 by Using U266 Cell and WST-8
Assay at 30 mmol.
MeO
B(OH)2
OAc
OAc
OCH3
Cu(OAc)2, LiOAc, Pd(OAc)2
DMF, 100oC, 2 h (82%)
AcO
OCH3
OCH3
AcO
OCH3
OCH3
MeO
2nd Grubbs, 40oC, 7 h
12
CH2Cl2 (21%)
Toluene (13%),
13
Scheme 1. Mizoroki-Heck Reaction Using Substrate 12.

Morinol C, D
1643
Table 2. Antibacterial Activity of 1–4 (MIC, mM)
(4S,5S)-5-(3,4-Dimethoxyphenyl)-5-triisopropylsilyloxy-4-(triisopro-
pylsilyloxy)methyl-1-pentene (8). To an ice-cooled solution of diol 5
(0.23 g, 0.91 mmol) and 2,6-lutidine (0.41 ml, 3.5 mmol) in CH2Cl2
(80 ml) was added TIPSOTf (0.60 ml, 2.2 mmol). The resulting
reaction solution was stirred at room temperature for 2 h before
addition of sat. aq. NaHCO3 solution. The organic solution was
separated, washed with sat. aq. CuSO4 solution and sat. aq. NaHCO3
solution, and dried (Na2SO4). Concentration followed by silica gel
column chromatography (5%EtOAc/hexane) gave diTIPS ether 8
1
2
3
4
Bucillus subtilis
Listeria denitrificans
Salmonella choleraesuis
50
50
50
50
25
6.3
>50
25
50
50
25
25
Experimental
20
(0.34 g, 0.60 mmol, 66%) as a colorless oil, ½ꢁꢂD ¼ ꢀ13 (c 1.3,
CHCl3). (½ꢁꢂD ¼ ꢀ14 (c 1.0, CHCl3) in the literature).4) The NMR
20
General experimental procedures. Melting point (mp) data are
uncorrected. NMR data were measured by a JNM-EX400 spectrom-
eter, using TMS as a standard (0 ppm), MS data were measured with a
JMS-MS700V spectrometer, and optical rotation values were evaluated
with a Jasco P-2100 polarimeter. Elemental analyses were carried out
with a Yanako MT-5 CHN coder, and the silica gel used was Wakogel
C-300 (Wako, 200–300 mesh).
data agreed with those in the literature.4)
(1S,2S)-1-(3,4-Dimethoxyphenyl)-2-[(E)-3-(4-methoxyphenyl)-2-
propen-1-yl]trimethylene dipivalate (9). Method A: A reaction
mixture of dipivalate 6 (50 mg, 0.12 mmol), 4-methoxyphenylboronic
acid (22 mg, 0.14 mmol), Cu(OAc)2 (43 mg, 0.24 mmol), LiOAc
(24 mg, 0.36 mmol), and Pd(OAc)2 (3.0 mg, 0.013 mmol) in DMF
(0.50 ml) was stirred at 100 ꢁC for 2 h before additions of EtOAc and
sat. aq. NH4Cl solution. The organic solution was separated, washed
with brine, and dried (Na2SO4). Concentration followed by silica gel
(1S,2S)-2-Allyl-1-(3,4-dimethoxyphenyl)-1,3-propanediol (5). To a
solution of (S)-4-benzyl-3-{(2R)-2-[(S)-(3,4-dimethoxyphenyl)(hy-
droxy)methyl]-4-pentenoyl}-2-oxazolidinone4) (7.30g, 17.2 mmol)
and MeOH (1.50ml) in THF (45 ml) was added a solution of LiBH4
(1.63 g, 74.8 mmol) in THF (100 ml) at 0 ꢁC. After stirring at 0 ꢁC for
1 h, 1 M aq. NaOH (80 ml) solution was added. The organic solution was
separated, washed with brine, and dried (NaSO4). Concentration
followed by silica gel column chromatography (EtOAc/hexane =
1/1) gave diol 5 (3.49g, 13.8 mmol, 80%) as colorless crystals, mp 74–
column chromatography (EtOAc/hexane 1/3) gave
9 (48 mg,
0.091 mmol, 76%). Method E: A reaction mixture of dipivalate 6
(50 mg, 0.12 mmol), 4-methoxystyrene (65 mg, 0.48 mmol), and 2nd
Grubbs catalyst (10 mg, 0.012 mmol) in CH2Cl2 (12 ml) was stirred at
40 ꢁC for 7 h before concentration. The residue was applied to silica gel
column chromatography (EtOAc/hexane = 1/7) to give 9 (19 mg,
20
0.036 mmol, 30%). 9: colorless oil, ½ꢁꢂD ¼ ꢀ8 (c 0.4, CHCl3). 1H-
75 ꢁC, ½ꢁꢂD ¼ ꢀ40 (c 0.22, CHCl3). 1H-NMR (CDCl3) ꢂ: 1.91–1.95
20
NMR (CDCl3) ꢂ: 1.20 (9H, s), 1.23 (9H, s), 2.10–2.22 (2H, m), 2.34
(1H, m), 3.79 (3H, s), 3.87 (6H, s), 4.14 (1H, dd, J ¼ 11:2, 4.0 Hz),
4.25 (1H, dd, J ¼ 11:2, 5.3 Hz), 5.70 (1H, d, J ¼ 8:1 Hz), 5.93 (1H,
m), 6.24 (1H, d, J ¼ 15:8 Hz), 6.82 (2H, d, J ¼ 8:6 Hz), 6.85 (1H, d,
J ¼ 2:3 Hz), 6.88 (1H, dd, J ¼ 8:8, 2.3 Hz), 7.21 (2H, d, J ¼ 8:6 Hz),
7.43 (1H, d, J ¼ 8:8 Hz). 13C-NMR (CDCl3) ꢂ: 27.1, 27.2, 31.3, 38.8,
38.9, 43.7, 55.3, 55.85, 55.88, 62.6, 74.9, 110.0, 111.0, 113.9, 114.1,
119.6, 124.5, 127.1, 127.4, 130.0, 131.5, 131.9, 148.8, 148.9, 158.9,
176.9. EIMS m=z (%): 526 (Mþ, 28), 322 (100), 291 (63), 147 (90).
HREIMS m=z Mþ: calcd. for C31H42O7, 526.2931; found, 526.2932.
(2H, m), 2.02 (1H, m), 3.00 (1H, t, J ¼ 6:6 Hz), 3.21 (1H, d,
J ¼ 4:6 Hz), 3.69 (1H, m), 3.84 (1H, m), 3.87 (3H, s), 3.89 (3H, s),
4.64 (1H, dd, J ¼ 9:2, 4.6 Hz), 5.00 (1H, d, J ¼ 15:1 Hz), 5.01 (1H, d,
J ¼ 13:1 Hz), 5.70 (1H, m), 6.83 (1H, d, J ¼ 8:1 Hz), 6.87 (1H, dd,
J ¼ 8:1, 1.7 Hz), 6.90 (1H, d, J ¼ 1:7 Hz). 13C-NMR (CDCl3) ꢂ: 33.0,
46.2, 55.9, 64.4, 78.4, 109.4, 110.9, 116.7, 118.9, 135.9, 136.1, 148.5,
149.1. Anal. Found: C, 66.36; H, 7.86%. Calcd. for C14H20O4: C,
20
66.65%; H, 7.99%. (1R,2R)-5, 80% yield, ½ꢁꢂD ¼ þ40 (c 1.0, CHCl3).
(1S,2S)-2-Allyl-1-(3,4-dimethoxyphenyl)trimethylene dipivalate (6).
To an ice-cooled solution of diol 5 (0.55 g, 2.2 mmol) in pyridine
(4.0 ml) was added PivCl (0.50 ml, 4.1 mmol). The resulting reaction
mixture was stirred at room temperature for 1 h before additions of
EtOAc and H2O. The organic solution was separated, washed with 6 M
aq. HCl solution, sat. aq. NaHCO3 solution, and brine, and dried
(Na2SO4). Concentration followed by silica gel column chromatog-
raphy (EtOAc/hexane = 1/7) gave dipivalate 6 (0.66 g, 1.6 mmol,
(1S,2S)-1-(3,4-Dimethoxyphenyl)-2-[(E)-3-(4-methoxyphenyl)-2-
propen-1-yl]trimethylene diacetate (10). Method A: 97% yield,
Method B: A reaction mixture of diacetate 7 (50 mg, 0.15 mmol),
1-iodo-4-methoxybenzene (40 mg, 0.17 mmol), Pd(OAc)2 (5.0 mg,
0.022 mmol), and Et3N (0.20 ml, 1.4 mmol) in MeCN (2.0 ml) was
stirred at 85 ꢁC for 16 h before additions of H2O and EtOAc. The
organic solution was separated, washed with brine, and dried
(Na2SO4). Concentration followed by silica gel column chromatog-
raphy (EtOAc/hexane = 1/3) gave 10 (14 mg, 0.032 mmol, 21%).
Method C: A reaction mixture of diacetate 7 (50 mg, 0.15 mmol),
1-bromo-4-methoxybenzene (30 mg, 0.16 mmol), PdCl2(PPh3)2
(10 mg, 0.014 mmol), and Et3N (70 ml, 0.50 mmol) in DMF (0.30 ml)
was stirred at 80 ꢁC for 4 h before additions of H2O and EtOAc. The
organic solution was separated, washed with brine, and dried
(Na2SO4). Concentration followed by silica gel column chromatog-
raphy (EtOAc/hexane = 1/3) gave 10 (5.0 mg, 0.011 mmol, 7%).
Method E: CH2Cl2 was used at 40 ꢁC, 34% yield. Toluene was used at
20
73%) as a colorless oil, ½ꢁꢂD ¼ ꢀ30 (c 0.74, CHCl3). 1H-NMR
(CDCl3) ꢂ: 1.20 (9H, s), 1.22 (9H, s), 1.98–2.10 (2H, m), 2.27 (1H, m),
3.87 (3H, s), 3.88 (3H, s), 4.10 (1H, dd, J ¼ 11:2, 4.1 Hz), 4.21 (1H,
dd, J ¼ 11:2, 5.2 Hz), 4.99 (1H, d, J ¼ 17:0 Hz), 5.04 (1H, d,
J ¼ 10:2 Hz), 5.67 (1H, d, J ¼ 8:2 Hz), 5.70 (1H, m), 6.82 (1H, s),
6.83 (1H, d, J ¼ 8:2 Hz), 6.87 (1H, d, J ¼ 8:2 Hz). 13C-NMR (CDCl3)
ꢂ: 27.0, 27.2, 32.0, 38.8, 38.9, 43.0, 55.8, 62.2, 74.7, 109.8, 110.9,
117.4, 119.4, 131.4, 135.2, 148.7, 148.9, 176.9, 178.3. EIMS m=z (%)
420 (Mþ, 39), 57 (100). HREIMS m=z Mþ: calcd. for C24H36O6,
420.2511; found, 420.2513.
20
40 ꢁC, 40% yield. 10: colorless oil, ½ꢁꢂD ¼ ꢀ8 (c 0.9, CHCl3). 1H-
NMR (CDCl3) ꢂ: 2.06 (6H, s), 2.08–2.20 (2H, m), 2.34 (1H, m), 3.79
(3H, s), 3.87 (3H, s), 3.88 (3H, s), 4.13 (1H, dd, J ¼ 11:2, 4.4 Hz), 4.30
(1H, dd, J ¼ 11:2, 5.3 Hz), 5.74 (1H, d, J ¼ 8:3 Hz), 5.93 (1H, m),
6.24 (1H, d, J ¼ 15:8 Hz), 6.74–6.85 (4H, m), 6.91 (1H, dd, J ¼ 8:3,
1.9 Hz), 7.22 (2H, d, J ¼ 8:7 Hz). 13C-NMR (CDCl3) ꢂ: 20.8, 21.1,
31.3, 43.1, 55.80, 55.84, 55.9, 62.7, 75.3, 110.2, 110.3, 110.9, 113.8,
119.7, 124.3, 127.0, 127.1, 130.0, 131.1, 131.8, 148.8, 148.9, 158.9,
169.9, 171.0. EIMS m=z (%): 442 (Mþ, 48), 322 (93), 167 (100), 147
(81), 121 (50). HREIMS m=z Mþ: calcd. for C25H30O7, 442.1992;
(1S,2S)-2-Allyl-1-(3,4-dimethoxyphenyl)trimethylene diacetate (7).
After a solution of diol 5 (0.46 g, 1.8 mmol) in pyridine (3.0 ml) and
Ac2O (3.0 ml) was stirred at room temperature for 5 h, ice was added.
The mixture was extracted with EtOAc. The organic solution was
separated, washed with 6 M aq. HCl solution, sat. aq. NaHCO3 solution,
and brine, and dried (Na2SO4). Concentration followed by silica gel
column chromatography (EtOAc/hexane = 1/3) gave diacetate 7
20
(0.43 g, 1.3 mmol, 72%) as a colorless oil, ½ꢁꢂD ¼ ꢀ36 (c 1.2,
CHCl3). 1H-NMR (CDCl3) ꢂ: 1.92–2.06 (2H, m), 2.06 (6H, s), 2.26
(1H, m), 3.87 (3H, s), 3.89 (3H, s), 4.08 (1H, dd, J ¼ 11:1, 4.3 Hz),
4.26 (1H, dd, J ¼ 11:1, 5.0 Hz), 4.99 (1H, d, J ¼ 17:3 Hz), 5.03 (1H, d,
J ¼ 10:2 Hz), 5.71 (1H, d, J ¼ 8:0 Hz), 5.70 (1H, m), 6.83–6.90 (3H,
m). 13C-NMR (CDCl3) ꢂ: 20.8, 21.1, 32.0, 42.5, 55.8, 55.9, 62.4, 75.1,
110.1, 110.9, 117.4, 119.6, 131.0, 134.9, 148.8, 148.9, 169.9, 170.9.
Anal. Found: C, 63.99; H, 7.21%. Calcd. for C18H24O6: C, 64.27%; H,
20
found, 442.1992. (1R,2R)-10: method A, 86% yield, ½ꢁꢂD ¼ þ5
(c 0.7, CHCl3).
(E)-(4S,5S)-5-(3,4-Dimethoxyphenyl)-1-(4-methoxyphenyl)-5-(triiso-
propylsilyloxy)-4-(triisopropylsilyloxy)methyl-1-pentene (11). Method
A: 32% yield. Method B: 11% yield: Z-isomer, 6% yield. Method E:
20
20
7.19%. (1R,2R)-7, 79% yield, ½ꢁꢂD ¼ þ36 (c 1.0, CHCl3).
25% yield by using toluene. 11: colorless oil, ½ꢁꢂD ¼ þ15 (c 0.23,

1644
K. OGURA et al.
CHCl3). (½ꢁꢂD ¼ þ24 (c 1.4, CHCl3) in the literature).4) NMR data
20
column AD-H, detected at 271 nm, 1 ml/min, iso-PrOH:hexane = 1:1,
tR 5.0 min).
agreed with those in the literature.4) Z-isomer: colorless oil,
20
½ꢁꢂD ¼ ꢀ42 (c 0.10, CHCl3). 1H-NMR (CDCl3) ꢂ: 0.95–1.00 (42H,
m), 1.00–1.08 (1H, overlapped), 1.62 (1H, dd, J ¼ 13:9, 11.6 Hz), 2.20
(1H, m), 3.11 (1H, dd, J ¼ 10:5, 10.5 Hz), 3.59 (1H, dd, J ¼ 10:5,
4.8 Hz), 3.81 (3H, s), 3.87 (3H, s), 3.90 (3H, s), 4.77 (1H, s), 5.12
(1H, s), 5.28 (1H, d, J ¼ 3:8 Hz), 6.80–6.83 (3H, m), 6.92 (1H, d,
J ¼ 9:9 Hz), 6.98 (1H, s), 7.36 (2H, d, J ¼ 8:7 Hz). 13C-NMR (CDCl3)
ꢂ: 11.9, 12.3, 18.0, 18.1, 31.0, 46.4, 55.3, 55.7, 55.8, 63.0, 72.8, 110.1,
110.6, 112.2, 113.5, 119.6, 127.7, 133.2, 134.4, 146.8, 147.7, 148.1,
159.1. FABMS m=z (%) 671 [ðM þ HÞþ, 0.4]. HRFABMS m=z
ðM þ HÞþ: calcd. for C39H67O5Si2, 671.4528; found, 671.4531.
Assay of cytotoxicity. The cytotoxicity of each compound was
determined by a WST-8 assay (Kishida Reagents Chemicals, Osaka,
Japan). Viable cells produce WST-8 formazan which is detectable by
the absorbance at 450 nm. U266 cells were seeded in the culture
medium containing various concentrations of each compound and
cultured for 24 h. The WST-8 solution was added to the culture
medium at 10% and incubated for 2 h, after which the absorbance at
450 nm was measured.
Organisms. Bacillus subtilis subsp. subtiis NBRC 13719T, Pseudo-
monas fluorescens NBRC 14160T, and Staphylococcus aureus subsp.
aureus NBRC 14462 were purchased from the Biological Resource
Center of National Institute of Technology and Evaluation (NITE),
Biological Resource Center, Japan. Escherichia coli JCM 1649,
Listeria denitrificans JCM 11481, Salmonella choleraesuis subsp.
choleraesuis JCM 6977 and Yersinia intermedia JCM 7579 were
obtained from RIKEN, Japan. The phytopathogenic fungi, Colleto-
trichum lagenarium, Bipolaris oryzae, Fusarium solani, and Alternaria
alternata, had been isolated from a farm at Ehime University and were
kindly presented by Dr. Ohguchi. Each fungus was cultured on potato
dextrose agar (PDA: Sigma-Aldrich, Canada).
(7S,8S)-Morinol C (1). A reaction solution of diacetate 10 (0.21 g,
0.47 mmol) in EtOH (3.0 ml) and 1 M aq. NaOH solution (3.0 ml) was
stirred at room temperature for 24 h before additions of CHCl3 and
H2O. The organic solution was separated and dried (Na2SO4).
Concentration followed by silica gel column chromatography
(EtOAc/hexane = 1/1) gave 1 (0.14 g, 0.39 mmol, 83%) as a colorless
20
20
oil, ½ꢁꢂD ¼ þ43 (c 0.72, CHCl3). (½ꢁꢂD ¼ þ48 (c 0.50, CHCl3) in
the literature).4) The NMR spectral agreed with those in the literature.4)
>99%ee (DAICEL chiral column AD-H, detected at 271 nm,
1 ml/min, iso-PrOH:hexane = 1:5, tR 19 min).
(7R,8R)-Morinol C (2). The NMR data agreed with those for
20
Antimicrobial assay. The antimicrobial assay was performed by the
same method as that described in the literature.12,15)
(7S,8S)-morinol C, 82% yield, ½ꢁꢂD ¼ ꢀ43 (c 0.33, CHCl3).
20
(½ꢁꢂD ¼ ꢀ48 (c 0.30, CHCl3) in the literature).4) The NMR spectral
data also agreed with those in the literature. >99%ee (DAICEL chiral
column AD-H, detected at 271 nm, 1 ml/min, iso-PrOH:hexane = 1:5,
tR 17 min).
Acknowledgments
We measured the 400 MHz NMR, MS and elemental
analysis data at INCS of Ehime University. We are
grateful to Marutomo Co. for financial support.
(1S,2R)-2-Allyl-1-(3,4-dimethoxyphenyl)trimethylene diacetate (12).
The title compound was obtained from (S)-4-benzyl-3-{(2S)-2-[(S)-(3,4-
dimethoxyphenyl)(hydroxy)methyl]-4-pentenoyl}-2-oxazolidinone11)
by the same method as that described for the synthesis of 5 and
References and Notes
acetylation in 84% yield through
2 steps as a colorless oil,
½ꢁꢂD ¼ ꢀ35 (c 1.1, CHCl3). 1H-NMR (CDCl3) ꢂ: 2.02 (3H, s), 2.09
(3H, s), 2.15–2.33 (3H, m), 3.78 (1H, dd, J ¼ 11:3, 4.6 Hz), 3.86 (3H,
s), 3.88 (3H, s), 4.02 (1H, dd, J ¼ 11:3, 5.3 Hz), 5.06 (1H, d,
J ¼ 14:2 Hz), 5.07 (1H, d, J ¼ 12:4 Hz), 5.71–5.81 (1H, m), 5.76 (1H,
d, J ¼ 7:2 Hz), 6.80–6.87 (3H, m). 13C-NMR (CDCl3) ꢂ: 20.7, 21.1,
31.7, 42.7, 55.78, 55.81, 63.1, 75.3, 109.7, 110.9, 117.2, 119.2, 131.0,
135.4, 148.7, 148.9, 169.9, 170.7. Anal. Found: C, 63.98; H, 7.16%.
Calcd. for C18H24O6: C, 64.27%; H, 7.19%. (1R,2S)-12: 88% yield,
20
1) Su B-N, Takaishi Y, and Kusumo T, Tetrahedron, 55, 14571–
14586 (1999).
2) Ayres DC and Loike JD, ‘‘Lignans,’’ Cambridge University
Press, New York (1990).
3) Ward S, Nat. Prod. Rep., 16, 75–96 (1999).
4) Yamauchi S and Uno H, Org. Biomol. Chem., 1, 1323–1329
(2003).
20
5) Method A: 4-methoxyphenylboronic acid, Cu(OAc)2, LiOAc,
and Pd(OAc)2 in DMF. Method B: 1-iodo-4-methoxybenzene,
Pd(OAc)2, Et3N in CH3CN. Method C: 1-bromo-4-methylben-
zene, PdCl2(PPh3)2 and Et3N in DMF. Method D: 1-iodo-4-
methoxybenzene, Pd(OAc)2 and K2CO3 in aqueous DMF.
Method E: 4-methoxystyrene in the presence of 2nd Grubbs
catalyst.
½ꢁꢂD ¼ þ36 (c 1.0, CHCl3).
(1S,2R)-1-(3,4-Dimethoxyphenyl)-2-[(E)-3-(4-methoxyphenyl)-2-
propen-1-yl]trimethylene diacetate (13). Method A: 82% yield.
Method E: by using CH2Cl2, 21% yield; by using toluene, 13% yield.
20
13: colorless oil, ½ꢁꢂD ¼ ꢀ20 (c 0.21, CHCl3). 1H-NMR (CDCl3) ꢂ:
2.02 (3H, s), 2.09 (3H, s), 2.25–2.38 (2H, m), 2.42 (1H, m), 3.80 (3H,
s), 3.80–3.88 (1H, overlapped), 3.87 (3H, s), 3.88 (3H, s), 4.07 (1H, dd,
J ¼ 11:3, 5.0 Hz), 5.80 (1H, d, J ¼ 6:8 Hz), 6.00 (1H, m), 6.34 (1H, d,
J ¼ 15:6 Hz), 6.82–6.88 (5H, m), 7.26 (2H, d, J ¼ 8:7 Hz). 13C-NMR
(CDCl3) ꢂ: 20.8, 21.2, 31.1, 43.4, 55.3, 55.86, 55.90, 63.4, 75.5, 109.8,
111.0, 113.9, 119.3, 124.9, 127.1, 130.1, 131.1, 131.6, 148.8, 149.0,
158.9, 170.1, 170.8. EIMS m=z (%) 442 (Mþ, 42), 322 (100), 291 (55),
167 (64), 151 (82), 147 (68), 121 (50). HREIMS m=z Mþ: calcd. for
6) Kishida M and Akita H, Tetrahedron, 61, 10559–10568 (2005).
7) Vidya R, Eggen M, Nair SK, Georg GI, and Himes RH, J. Org.
Chem., 68, 9687–9693 (2003).
8) Cesati III RR, Armas J, and Hoveyda AH, J. Am. Chem. Soc.,
126, 96–101 (2004).
9) Ku J-M, Jeong B-S, Jew S, and Park H, J. Org. Chem., 72,
8115–8118 (2007).
10) Scholl M, Ding S, Lee CW, and Grubbs RH, Org. Lett., 1, 953–
956 (1999).
C
25H30O7, 442.1992; found, 442.1990. (1R,2S)-13: method A, 86%
20
yield, ½ꢁꢂD ¼ þ23 (c 0.54, CHCl3).
11) Yamauchi S, Okazaki M, Akiyama K, Sugahara T, Kishida T,
and Kashiwagi T, Org. Biomol. Chem., 3, 1670–1675 (2005).
12) Akiyama K, Yamauchi S, Nakato T, Maruyama M, Sugahara T,
and Kishida T, Biosci. Biotechnol. Biochem., 71, 1028–1035
(2007).
(7S,8R)-Morinol D (3). The title compound was obtained from 13
by the same method as that described for 1 as a colorless oil in 96%
20
20
yield, ½ꢁꢂD ¼ þ14 (c 0.33, CHCl3). (½ꢁꢂD ¼ þ22 (c 0.50, CHCl3)
in the literature).4) The NMR spectral data also agreed with those in the
literature.4) >99%ee (DAICEL chiral column AD-H, detected at
271 nm, 1 ml/min, iso-PrOH:hexane = 1:1, tR 5.7 min).
13) Akiyama K, Maruyama M, Yamauchi S, Nakashima Y, Nakato
T, Tago R, Sugahara T, Kishida T, and Koba Y, Biosci.
Biotechnol. Biochem., 71, 1745–1751 (2007).
14) Kawaguchi Y, Yamauchi S, Masuda K, Nishiwaki H, Akiyama
K, Maruyama M, Sugahara T, Kishida T, and Koba Y, Biosci.
Biotechnol. Biochem., 73, 1806–1810 (2009).
(7R,8S)-Morinol D (4). The NMR data agreed with those for
20
(7S,8R)-morinol D, 91% yield, ½ꢁꢂD ¼ ꢀ14 (c 0.50, CHCl3).
(½ꢁꢂD ¼ ꢀ22 (c 0.40, CHCl3) in the literature).4) The NMR spectral
20
15) Maruyama M, Yamauchi S, Akiyama K, Sugahara T, Kishida T,
and Koba Y, Biosci. Biotechnol. Biochem., 71, 677–680 (2007).
data also agreed with those in the literature.4) >99%ee (DAICEL chiral