Journal of Natural Products
ARTICLE
EtOAc (3 ꢀ 30 mL). The combined extracts were washed with water
(30 mL), dried (MgSO4), and evaporated under reduced pressure. Flash
chromatography on silica gel using hexane/EtOAc (20:1) afforded 12
(0.337 g, 61%) as an oil: 1H NMR (300 MHz, CDCl3) δ 7.49 (2H, d, J =
7.2 Hz), 7.34 (2H, dd, J = 7.5, 7.2 Hz), 7.23 (1H, t, J = 7.5 Hz), 7.03 (2H,
s), 6.94 (2H, s), 5.24 (4H, s), 5.21(1H, t, J = 7.2 Hz), 3.50 (6H, s), 3.39
(2H, d, J = 7.2 Hz), 1.79 (3H, s), 1.67 (3H, s); 13C NMR (75 MHz,
CDCl3) δ 155.8, 155.8, 137.3, 136.3, 131.1, 128.8, 128.6, 128.6, 128.3,
127.5, 126.5, 126.5, 122.7, 119.9, 106.2, 106.2, 94.5, 94.5, 56.0, 56.0, 25.8,
22.8, 17.5; IR (neat) 2912 (C-H), 1600, 1576, 1438, 1394, 1316, 1211,
1153, 1102, 1048, 944, 750 cm-1; HREIMS, 70 eV, m/z 368.1990 (calcd
for C23H28O4 368.1988).
56.2, 33.1, 22.7, 22.7; IR (neat) 2955 (C-H), 1600, 1447, 1393, 1152,
1044, 965, 824, 739 cm-1; HREIMS, 70 eV, m/z 368.1985 (calcd for
C23H28O4 368.1988).
Arahypin-1 (3) from Compound 14. To a solution of 14 (0.184 g,
0.5 mmol) in MeOH (5 mL) was added concentrated HCl (0.5 mL),
and the reaction mixture was stirred at room temperature for 10 h. The
reaction was diluted with saturated NaHCO3 solution (30 mL) and
extracted with EtOAc (3 ꢀ 30 mL). Removal of solvent at reduced
pressure left an oily residue, which was then purified by CC on silica
gel with hexane/EtOAc (4:1) to give 3 (0.035 g, 25%) as an oil: IR
(neat) 3409 (OH), 2949 (C-H), 1624, 1574, 1433, 1360, 1301, 1028,
1
975, 828 cm-1; H NMR (300 MHz, CDCl3) δ 7.46 (2H, d, J =
Chiricanine A (2). To a solution of 12 (0.184 g, 0.5 mmol) in
MeOH (5 mL) was added concentrated HCl (0.2 mL), and the reaction
mixture was stirred at room temperature for 10 h. The reaction mixture
was diluted with saturated NaHCO3 solution (30 mL) and extracted
with EtOAc (3 ꢀ 30 mL). Removal of solvent at reduced pressure left an
oily residue, which was then purified by CC on silica gel with hexane/
7.6 Hz), 7.33 (2H, t, J = 7.6 Hz), 7.24 (1H, t, J = 7.6 Hz), 7.03 (1H, d,
J = 16.2 Hz), 6.93 (1H, d, J = 16.2 Hz), 6.63 (2H, s), 6.31 (1H, d, J =
16.5 Hz), 6.15 (1H, dd, J = 16.5, 6.6 Hz), 5.34 (1H, br s), 2.60-2.49
(1H, m), 1.13 (6H, d, J = 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ
153.8, 153.8, 145.7, 137.6, 137.0, 129.1, 128.6, 128.6, 127.9, 127.6,
126.5, 126.5, 117.3, 111.8, 105.8, 105.8, 32.2, 22.3, 22.3; HREIMS, 70
eV, m/z 280.1466 (calcd for C19H20O2 280.1463).
1
EtOAc (4:1) to give 2 (0.094 g, 67%) as an oil: H NMR (300 MHz,
CDCl3) δ 7.46 (2H, d, J = 7.2 Hz), 7.34 (2H, t, J = 7.2 Hz), 7.24 (1H, t, J
= 7.2 Hz), 6.99 (1H, d, J = 16.5 Hz), 6.91 (1H, d, J = 16.5 Hz), 6.57 (2H,
s), 5.27 (1H, t, J = 6.9 Hz), 3.42 (2H, d, J = 6.9 Hz), 1.82 (3H, s), 1.76
(3H, s); 13C NMR (75 MHz, CDCl3) δ 155.0, 155.0, 137.2, 136.8,
135.6, 128.7, 128.7, 128.6, 128.0, 127.6, 126.5, 126.5, 121.3, 113,2, 106.5,
106.5, 25.8, 22.5, 17.9; IR (neat) 3412 (O-H), 2973 (C-H), 2925
Arahypin-1 (3) from Compound10. Toasolutionof10(0.212g,
1.0 mmol) and isovaleraldehyde (0.129 g, 1.5 mmol) in benzene (20 mL)
was added ethylenediamine diacetate (36 mg, 0.2 mmol) at room
temperature. The reaction mixture was refluxed for 10 h and then cooled
to room temperature. Evaporation of solvent and purification by CC on
silica gel using hexane/EtOAc (4:1) gave 3 (0.151 g, 54%) as an oil. The
spectral data were the same as described above.
(C-H), 1611, 1584, 1445, 1352, 1264, 1158, 1051, 963, 826, 743 cm-1
HREIMS, 70 eV, m/z 280.1466 (calcd for C19H20O2: 280.1463).
;
(E)-3,5-Bis-methoxymethoxy-40-triisopropylsilyloxystil-
bene (17). To a solution of aldehyde 15 (0.679 g, 3.0 mmol) and
benzyl phosphonate 16 (1.202 g, 3.0 mmol) in THF (30 mL) was added
t-BuOK (0.717 g, 6.4 mmol) at 0 °C. The reaction mixture was stirred at
0 °C for 5 h. The reaction was quenched by addition of H2O (30 mL)
and extracted with EtOAc (3 ꢀ 30 mL). The combined organic layer was
washed with NH4Cl solution (30 mL), H2O (30 mL), and brine
(30 mL), dried over MgSO4, and concentrated at reduced pressure.
The removal of the solvent under reduced pressure left an oily residue,
which was then purified by CC on silica gel using hexane/EtOAc (4:1)
to give 17 (1.163 g, 82%) as an oil: 1H NMR (300 MHz, CDCl3) δ 7.35
(2H, d, J = 9.0 Hz), 7.01 (1H, d, J = 16.2 Hz), 6.88-6.81 (5H, m), 6.60
(1H, t, J = 2.0 Hz), 5.17 (4H, s), 3.48 (6H, s), 1.41-1.20 (3H, m), 1.09
(18H, d, J = 7.2 Hz); 13C NMR (75 MHz, CDCl3) δ 158.2, 158.2, 155.7,
139.7, 129.8, 128.8, 127.5, 127.5, 126.0, 119.8, 119.8, 107.4, 107.4, 103.6,
94.2, 94.2, 55.7, 55.7, 17.6 (6 carbons), 12.4 (3 carbons); IR (neat) 2952
(C-H), 2868 (C-H), 1597, 1509, 1463, 1396, 1275, 1151, 1037, 918,
841 cm-1; HREIMS, 70 eV, m/z 472.2646 (calcd for C27H40O5Si
472.2645).
(E)-3,5-Bis-methoxymethoxy-2-(1-hydroxy-3-methylbutyl)-
stilbene (13). n-BuLi (0.8 mL, 2.5 M in hexane, 2.0 mmol) was added
at 0 °C to a solution of 11 (0.541 g, 1.8 mmol) in THF (20 mL), and the
resulting solution was stirred at 0 °C for 2 h. Isovaleraldehyde (0.164 g,
1.9 mmol) was added dropwise to the reaction mixture at 0 °C, which
was stirred at room temperature for 10 h. The reaction mixture was
quenched with saturated NH4Cl solution (20 mL) and extracted with
EtOAc (3 ꢀ 30 mL). The extract was washed with H2O (30 mL), dried
(MgSO4), and evaporated under reduced pressure. Flash chromatogra-
phy on silica gel using hexane/EtOAc (4:1) afforded 13 (0.494 g, 71%)
as an oil: 1H NMR (300 MHz, CDCl3) δ 7.49 (2H, d, J = 7.2 Hz), 7.34
(2H, t, J = 7.2 Hz), 7.24 (1H, t, J = 7.2 Hz), 7.01 (1H, d, J = 16.2 Hz), 7.07
(1H, d, J = 16.2 Hz), 6.97 (2H, s), 5.28-5.25 (1H, m), 5.26 (4H, s), 3.50
(6H, s), 1.93-1.84 (1H, m), 1.80-1.71 (1H, m), 1.67-1.58 (1H, m),
0.99 (3H, d, J = 6.6 Hz), 0.95 (3H, d, J = 6.6 Hz); 13C NMR (75 MHz,
CDCl3) δ 155.5, 155.5, 137.7, 137.0, 129.0, 128.6, 128.6, 128.2, 127.6,
126.5, 126.5, 121.3, 106.3, 106.3, 94.5, 94.5, 66.3, 56.2, 56.2, 47.0, 25.0,
23.2, 22.4; IR (neat) 3600 (O-H), 2953 (C-H), 1603 (C-H), 1576,
1448, 1215, 1152, 1100, 1042, 921, 751 cm-1; HREIMS, 70 eV, m/z
386.2097 (calcd for C23H30O5 386.2093).
(E)-3,5-Bis-methoxymethoxy-2-{(E)-3-methylbut-1-enyl)}-
stilbene (14). Compound 13 (0.425 g, 1.1 mmol) was dissolved in
pyridine (10 mL), and the reaction mixture was cooled to 0 °C. POCl3
(0.506 g, 3.3 mmol) was added dropwise. The reaction was stirred at
room temperature for 1 h, then heated at 100 °C for 1 h. After cooling to
room temperature, the reaction mixture was diluted with EtOAc
(50 mL) and poured into 2 N HCl (50 mL), and the phases were
separated. The aqueous phase was extracted with EtOAc (3 ꢀ 30 mL).
The extract was washed with 2 N HCl (50 mL) and brine (50 mL), dried
(MgSO4), and concentrated under reduced pressure. Flash chromatog-
raphy on silica gel using hexane/EtOAc (4:1) afforded 14 (0.259 g, 64%)
as an oil: 1H NMR (300 MHz, CDCl3) δ 7.50 (2H, d, J = 7.2 Hz), 7.34
(2H, t, J = 7.2 Hz), 7.25 (1H, t, J = 7.2 Hz), 7.01 (1H, d, J = 16.2 Hz), 7.07
(1H, d, J = 16.0 Hz), 6.95 (2H, s), 6.60-6.58 (2H, m), 5.24 (4H, s), 3.52
(6H, s), 2.53-2.43 (1H, m), 1.10 (6H, d, J = 6.6 Hz); 13C NMR (75
MHz, CDCl3) δ 155.9, 155.9, 143.1, 137.2, 136.5, 128.7, 128.6, 128.6,
128.5, 128.5, 127.6, 126.5, 126.5, 117.2, 107.2, 107.2, 94.9, 94.9, 56.2,
(E)-3,5-Bis-methoxymethoxy-2-(3-methylbut-2-enyl)-40-
triisopropylsilyloxystilbene (18). n-BuLi (0.44 mL, 2.5 M in
hexane, 1.1 mmol) was added at 0 °C to a solution of 17 (0.473 g,
1.0 mmol) in THF (20 mL), and the resulting solution was stirred at
0 °C for 2 h. Prenyl bromide (0.164 g, 1.1 mmol) was added dropwise to
the reaction mixture at 0 °C, which was stirred at room temperature for
10 h. The reaction was quenched with saturated NH4Cl solution
(20 mL) and extracted with EtOAc (3 ꢀ 30 mL). The combined
extracts were washed with H2O (30 mL), dried (MgSO4), and evapo-
rated under reduced pressure. Flash chromatography on silica gel using
1
hexane/EtOAc (5:1) afforded 18 (0.433 g, 80%) as an oil: H NMR
(300 MHz, CDCl3) δ 7.36 (2H, d, J = 7.8 Hz), 7.01-6.84 (6H, m), 5.23
(4H, s), 5.22 (1H, t, J = 6.5 Hz), 3.50 (6H, s), 3.39 (2H, d, J = 6.5 Hz),
1.78 (3H, s), 1.67 (3H, s), 1.38-1.19 (3H, m), 1.11 (18H, d, J = 6.6 Hz);
13C NMR (75 MHz, CDCl3) δ 155.8, 155.8, 155.7, 136.8, 131.0, 130.4,
128.0, 127.6, 127.6, 126.7, 122.8, 120.1, 120.1, 119.5, 106.0, 106.0, 94.5,
94.5, 56.0, 56.0, 25.8, 22.8, 17.9 (6 carbons), 17.8, 12.7 (3 carbons);
IR (neat) 2947 (C-H), 1599, 1511, 1452, 1271, 1156, 1053, 916 cm-1
HREIMS, 70 eV, m/z 540.3268 (calcd for C32H48O5Si 540.3271).
;
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dx.doi.org/10.1021/np100696f |J. Nat. Prod. 2011, 74, 644–649