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111.20 (C-20), 56.19 (30-OCH3), 55.56 (3-OCH3), 52.46
(9-OCH3), 51.68 (90-OCH3).
(4) (98 mg, 84%). DCI-MS (m/z) 518 (M+NH4)+; H
NMR (CDCl3, 300 MHz) d 7.49 (d, J = 16 Hz, 1H, H-
70), 6.93 (s, 1H, H-60), 6.87 (s, 1H, H-20), 6.75 (d,
J = 1.2 Hz, 1H, H-2), 6.70 (dd, J = 8.1 Hz, J = 1.8 Hz,
1H, H-6), 6.67 (d, J = 8.1 Hz, 1H, H-5), 6.15 (d,
J = 15.9 Hz, 1H, H-80), 5.48 (d, J = 6.9 Hz, 1H, H-7),
3.80 (m, 2H, C-9), 3.77 (s, 3H, 30-OCH3), 3.65 (s, 3H,
3-OCH3), 3.63 (s, 3H, 90-OCH3), 3.50 (m, 1H, C-8),
0.85 (s, 9H, t-Bu), 0.00 (s, 6H, Si–CH3); 13C NMR
(CDCl3, 75 MHz) d 167.73 (C-90), 151.07 (C-40),
150.64 (C-3), 145.21 (C-4), 144.96 (C-70), 144.53 (C-30),
133.91 (C-1), 128.77 (C-10), 128.32 (C-50), 120.83 (C-6),
118.69 (C-60), 117.33 (C-80), 115.02 (C-5), 111.76 (C-
20), 110.12 (C-2), 88.62 (C-7), 63.86 (C-9), 56.01 (30-
OCH3), 55.95 (3-OCH3), 55.49 (C-8), 53.10 (9-OCH3),
51.57 (90-OCH3), 25.65 (CH3, t-Bu), 18.38 (C, t-Bu),
ꢀ4.69 (Si–CH3).
5.1.3. Methyl (E)-3-[2-(4-tertiobutyldimethylsilyloxy-3-
methoxyphenyl)-7-methoxy-3-methoxycarbonyl-2,3-dihy-
dro-1-benzofuran-5-yl]-prop-2-enoate (3). Diisopropyl-
ethylamine (1.23 mL, 7.43 mmol) was syringed into a
solution of (2) (0.86 g, 2.08 mmol) and tert-butyldimeth-
ylsilyl chloride (0.94 g, 6.26 mmol) in 26 mL of dry
DMF under Ar. The reaction mixture was stirred for
2 h 30 min at room temperature and was poured into
ice-cold water. The product was extracted into Et2O.
The combined organic layers were washed with brine,
dried over Na2SO4 and evaporated under reduced pres-
sure to provide an oil (1.08 g, 97%). DCI-MS (m/z) 546
(M+NH4)+; 1H NMR (CDCl3, 300 MHz) d 7.51 (d,
J = 16 Hz, 1H, H-70), 7.05 (s, 1H, H-60), 6.88 (s, 1H,
H20), 6.74 (d, J = 1.8 Hz, 1H, H-2), 6.72 (dd,
J = 8.1 Hz, J = 1.8 Hz, 1H, H-6), 6.67 (dd, J = 8.1 Hz,
J = 1.8 Hz, 1H, H-5), 6.17 (d, J = 15.9 Hz, 1H, H-80),
5.98 (d, J = 8.4 Hz, 1H, H-7), 4.23 (d, J = 8.0 Hz, 1H,
H-8), 3.78 (s, 3H, 30-OCH3), 3.70 (s, 3H, 3-OCH3),
3.67 (s, 3H, 9-OCH3), 3.65 (s, 3H, 90-OCH3), 0.84 (s,
9H, t-Bu), 0.00 (s, 6H, Si–CH3). 13C NMR (CDCl3,
75 MHz) d 170.72 (C-9), 167.55 (C-90), 151.11 (C-40),
149.96 (C-3), 145.48 (C-4), 144.70 (C-70), 144.66 (C-30),
132.81 (C-1), 128.49 (C-10), 125.69 (C-50), 120.95 (C-6),
118.73 (C-60), 117.88 (C-80), 115.47 (C-5), 112.02 (C-
20), 110.10 (C-2), 87.42 (C-7), 56.07 (30-OCH3), 55.51
(3-OCH3), 55.39 (C-8), 52.82 (9-OCH3), 51.58 (90-
OCH3), 25.65 (CH3, t-Bu), 18.39 (C, t-Bu), ꢀ4.68 (Si–
CH3).
5.1.6.
(Z)-3-(4-tertiobutyldimethylsilyloxy-3-methoxy-
phenyl)-2-{2-methoxy-4-[(E)-3-hydroxy prop-1-enyl]phen-
oxy}-prop-2-enol (40). Compound (30) (11.4 mg,
21.6 lmol) dissolved in 1 mL of toluene freshly distilled,
under nitrogen, was cooled in an ice-water bath, and dii-
sobutylaluminium hydride (30 lL of 1.5 M solution,
181 lmo1, 8.4 equiv) in toluene was slowly added. After
addition was complete, stirring was performed for one
night. The reaction mixture was then carefully quenched
with ethanol (5 mL). The solvents were partially re-
moved under vacuo at 40 ꢁC. Water (10 mL) was added,
and the aqueous layer was extensively extracted with
ethyl acetate. The combined organic layers were dried
over Na2SO4 and evaporated to dryness under reduced
pressure. The residue was purified by silica gel chroma-
tography with petroleum ether/EtOAc (5:5) yielding pur
diol (40) (6.7 mg, 66%).
5.1.4. Methyl (Z)-3-(4-tertiobutyldimethylsilyloxy-3-
methoxyphenyl)-2-{2-methoxy-4-[(E)-3-methoxy-3-oxo-
prop-1-enyl]phenoxy}-prop-2-enoate (30). It was synthe-
tized by the same procedure as for compound (3)
DCI-MS (m/z) 490 (M+NH4)+; 1H NMR (CDCl3,
300 MHz) d 7.14 (s, 2H, 9-OH, 90-OH), 7.11 (d,
J = 1.8 Hz, 1H, H-2), 6.88 (d, J = 1.8 Hz, 1H, H-20),
6.86 (dd, J = 8.1 Hz, J = 2.1 Hz, 1H, H-60), 6.80 (d, ,
J = 8.1 Hz, 1H, H-5), 6.73 (dd, J = 8.1 Hz, J = 1.8Hz,
1H, H-6), 6.63 (d, , J = 8.4 Hz, 1H, H-50), 6.43 (d,
J = 15.9 Hz, 1H, H-70), 6.18 (dt, J = 15.9 Hz,
J = 5.7 Hz, 1H, H-80), 5.96 (s, 1H, H-7), 4.19 (dd,
J = 5.7 Hz, J = 1.2 Hz, 2H, H-90), 4.04 (s, 2H,C-9),
3.80 (s, 3H, 30-OCH3), 3.55 (s, 3H, 3-OCH3), 0.86 (s,
9H, C(CH3)3), 0.00 (s, 6H, CH3).
1
(yield 71%). DCI-MS (m/z) 546 (M+NH4)+; H NMR
(CDCl3, 300 MHz) d 7.48 (d, J = 16 Hz, 1H, H-70),
7.20 (d, J = 1.8 Hz, 1H, H-2), 7.14 (s, 1H, H-7), 7.00
(d, J = 1.8 Hz, 1H, H-20), 6.97 (dd, J = 8.5 Hz,
J = 2 Hz, 1H, H-6), 6.86 (dd, J = 8.5 Hz, J = 2 Hz, 1H,
H-60), 6.66 (d, J = 8.5 Hz, 1H, H-5), 6.63 (d,
J = 8.5 Hz, 1H, H-50), 6.18 (d, J = 16 Hz, 1H, H-80),
3.85 (s, 3H, 30-OCH3), 3.66 (s, 3H, 90-OCH3), 3.64 (s,
3H, 9-OCH3), 3.54 (s, 3H, 3-OCH3), 0.83 (s, 9H,
C(CH3)3), 0.00 (s, 6H, CH3).
5.1.5. Methyl (E)-3-[2-(4-tertiobutyldimethylsilyloxy-3-
methoxyphenyl)-3-hydroxymethyl-7-methoxy-2,3-dihy-
dro-1-benzofuran-5-yl]-prop-2-enoate (4). LiBH4 (33 mg;
1.5 mmol) was suspended in dry THF (3 mL) and added
to a solution of compound (3) (123 mg; 0.23 mmol) dis-
solved in dry THF (5 mL) under argon at ꢀ78 ꢁC. The
reaction mixture was stirred for 30 min h at ꢀ78 ꢁC then
2 h at room temperature. Aqueous THF (80%, 10 mL)
was added slowly and aqueous 0.1 M ammonium chlo-
ride (5 mL) was then added. The mixture was extracted
with EtOAc (3· 10 mL), and the combined organic ex-
tracts were washed with water, dried over Na2SO4,
and evaporated under reduced pressure. The residue
was purified by silica gel chromatography with petro-
leum ether/EtOAc (45:55) yielding pure monoalcohol
5.1.7. Methyl (E)-3-[2-(4-hydroxy-3-methoxyphenyl)-3-
hydroxymethyl-7-methoxy-2,3-dihydro-1-benzofuran-5-
yl]-prop-2-enoate (5). The title compound was synthe-
tized from compound (2) by the same procedure as for
compound (4) synthesis (yield 87%). DCI-MS (m/z)
404 (M+NH4)+; 1H NMR (DMSO-d6, 500 MHz) d
9.09(s, H, 4-OH), 7.62 (d, J = 16.0 Hz, 1H, H-70),
7.29(s, 1H, H-20), 7.28 (s, 1H, H-60), 6.93 (s, 1H, H-2),
6.78 (s, 2H, H-5, H-6), 6.53 (d, J = 16.0 Hz, 1H, H-80),
5.56 (d, J = 6.5 Hz, , 1H, H-7), 5.09 (m, 1H, OH-9),
3.84 (s, 3H, OCH3), 3.80 (s, 3H, OCH3), 3.74 (m, 1H,
H-9b), 3.72 (s, 3H, OCH3), 3.67 (m, 1H, H-9a), 3.51
(td, J = 6.0 Hz, J = 6.0 Hz, 1H, H-8);13C NMR
(DMSO-d6, 75 MHz) d 167.53 (C-90), 145.59 (C-70),
150.44 (C-40), 148.05 (C-3), 147.01 (C-4), 144.44 (C-30),