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Ar–H ꢂ 2), 6.59 (1H, d, J 15.0, CH@), 6.37 (1H, t, J 2.5, Ar–H), 3.83
(6H, s, OMe ꢂ 2), 3.68 (3H, s, OMe), 2.95–2.75 (2H, m,
CH(CH2Me)2 ꢂ 2), 1.80–1.40 (8H, m, CH(CH2Me)2 ꢂ 2) and 0.83
(12H, t, J 7.5, CH(CH2Me)2 ꢂ 2); 13C NVR d 160.9, 157.8, 139.6,
138.8, 133.7, 133.2, 131.7, 130.0, 127.6, 122.5, 104.3, 99.7, 61.9,
55.3, 40.8, 29.4 and 12.3. Anal. Calcd for C29H40O3: C, 79.77; H,
9.23. Found: C, 79.69; H, 9.36.
126.5, 125.6, 116.2, 105.7, 102.5, 42.7, 29.1 and 12.5. MS (EI) m/z:
298.1 (M)+. Anal. Calcd for C19H22O3: C, 76.48; H, 7.43. Found: C,
76.55; H, 7.38.
5.3.1.2. 5-{(E )-2-[3,5-Bis(1-ethylpropyl)-4-hydroxyphenyl]eth-
enyl}-1,3-benzenediol (2). Purification of the crude residue by
flash column chromatography (hexane/ether 80:20) afforded stil-
bene 2 as a light yellow solid (420 mg, 47%). Mp 115–120 °C. 1Y
NVR d 7.07 (2H, s, Ar–H ꢂ 2), 6.99 (1H, d, J 16.0, CH@), 6.79 (1H,
d, J 16.0, CH@), 6.57 (2H, s, Ar–H ꢂ 2), 6.24 (1H, s, Ar–H), 2.75–
2.50 (2H, m, CH(CH2Me)2 ꢂ 2), 2.00–1.45 (8H, m, CH(CH2Me)2 ꢂ 2)
and 0.83 (12H, t, J 7.5, CH(CH2Me)2 ꢂ 2); 13C NVR d 156.8, 152.4,
140.7, 130.9, 130.3, 129.2, 124.9, 123.3, 105.8, 101.6, 42.0, 28.4
and 12.1. MS (EI) m/z: 368.3 (M)+. Anal. Calcd for C24H32O3: C,
78.22; H, 8.75. Found: C, 78.18; H, 8.76.
5.2.6. 2-tert-Butyl-4-[(1E,3E)-4-(3,5-dimethoxyphenyl)-1,3-
butadienyl]-1-methoxybenzene (14g)
Purification of the crude residue by flash column chromatogra-
phy (hexane/ether 90:10) afforded stilbene 14g as a white solid
(1.0 g, 54%). Mp 95-98 °C. 1Y NVR d 7.37 (1H, d, J 2.0, Ar–H), 7.27
(1H, dd, J 8.0 and 2.0, Ar–H), 6.99–6.76 (3H, m, Ar–H and CH@ ꢂ 2),
6.65 (1H, d, J 15.5, CH@), 6.60 (2H, d, J 2.0, Ar–H ꢂ 2), 6.56 (1H, d, J
15.5, CH@), 6.36 (1H, t, J 2.0, Ar–H), 3.85 (3H, s, OMe), 3.82 (6H, s,
OMe ꢂ 3) and 1.40 (9H, s, CMe3); 13C NVR d 160.9, 158.5, 139.6,
138.4, 133.5, 131.2, 130.2, 129.4, 126.6, 125.2, 124.9, 111.7,
104.2, 99.7, 55.3, 55.0, 34.8 and 29.6. Anal. Calcd for C23H38O3: C,
78.38; H, 8.01. Found: C, 78.24; H, 8.00.
5.3.1.3. 5-{(1E,3E )-4-[3-(1-Ethylpropyl)-4-hydroxyphenyl]-1,3-
butadienyl}-1,3-benzenediol (5). Purification of the crude
residue by flash column chromatography (hexane/ether 80:20)
afforded stilbene 5 as a yellow amorphous solid (410 mg, 80%).
1Y NVR (CD3OD) d 7.20–7.00 (2H, m, Ar–H ꢂ 2), 6.85–6.70 (3H,
m, Ar–H and CH@ ꢂ 2), 6.56 (1H, d, J 15.0, CH@), 6.43 (1H, d, J
15.0, CH@), 6.39 (2H, d, J 2.0, Ar–H ꢂ 2), 6.15 (1H, t, J 2.0, Ar–H),
3.00–2.80 (1H, m, CH(CH2Me)2), 1.75–1.50 (4H, m, CH(CH2Me)2)
and 0.79 (6H, t, J 7.5, CH(CH2Me)2); 13C NVR (CD3OD) d 159.6,
156.9, 141.2, 134.5, 133.0, 132.2, 130.9, 130.5, 127.3, 127.2, 125.6,
116.2, 105.6, 102.8, 42.7, 29.2 and 12.5. MS (EI) m/z: 324.2 (M)+.
Anal. Calcd for C21H24O3: C, 77.75; H, 7.46. Found: C, 77.65; H, 7.49.
5.2.7. 1,3-Di-tert-butyl-5-[(1E,3E)-4-(3,5-dimethoxyphenyl)-1,3-
butadienyl]-2-methoxybenzene (14h)
Purification of the crude residue by flash column chromatogra-
phy (hexane/ether 90:10) afforded stilbene 14h as a white solid
(3.2 g, 88%). Mp 117–123 °C. 1Y NVR d 7.35 (2H, s, Ar–H ꢂ 2),
7.10–6.80 (2H, m, CH@ ꢂ 2), 6.67 (1H, d, J 15.0, CH@), 6.62 (2H,
d, J 2.0, Ar–H ꢂ 2), 6.48 (1H, d, J 15.0, CH@), 6.39 (1H, t, J 2.0, Ar–
H), 3.84 (6H, s, OMe ꢂ 2), 3.72 (3H, s, OMe) and 1.47 (18H, s,
CMe3 ꢂ 2); 13C NVR d 160.8, 159.6, 143.8, 139.5, 133.7, 131.7,
131.5, 130.0, 127.5, 124.7, 104.2, 99.7, 64.2, 55.3, 35.7 and 32.0.
Anal. Calcd for C27H36O3: C, 79.37; H, 8.88. Found: C, 79.309; H,
8.86.
5.3.1.4. 5-{(1E,3E )-4-[3,5-Bis(1-ethylpropyl)-4-hydroxyphenyl]-
1,3-butadienyl}-1,3-benzenediol (6). Purification of the crude
residue by flash column chromatography (hexane/ether 80:20)
afforded stilbene 6 as a light yellow solid (280 mg, 65%). Mp
155–158 °C. 1Y NVR (CD3OD) d 7.05 (2H, s, Ar–H ꢂ 2), 6.95–6.70
(2H, m, CH@ ꢂ 2), 6.61 (1H, d, J 15.0, CH@), 6.48 (1H, d, J 15.0,
CH@), 6.42 (2H, s, Ar–H ꢂ 2), 6.18 (1H, s, Ar–H), 3.00–2.85 (2H,
m, CH(CH2Me)2 ꢂ 2), 1.75–1.55 (8H, m, CH(CH2Me)2 ꢂ 2) and
0.83 (12H, t, J 6.5, CH(CH2Me)2 ꢂ 2); 13C NVR (CD3OD) d 159.6,
154.8, 141.2, 134.9, 133.4, 132.2, 130.9, 130.8, 127.1, 123.8,
105.7, 102.8, 42.3, 29.7 and 12.4. MS (EI) m/z: 394.3 (M)+. Anal.
Calcd for C26H34O3: C, 79.15; H, 8.69. Found: C, 78.94; H, 8.71.
5.2.8. 1,3-Di-tert-butyl-5-[(E)-2-(3,5-di-tert-butyl-4-metho-
xyphenyl)ethenyl]-2-methoxybenzene (14k)
Purification of the crude residue by recrystallisation from MeOH
afforded stilbene 14k as a light yellow amorphous solid (1.25 g,
46%). 1Y NVR d 7.40 (4H, s, Ar–H ꢂ 4), 6.95 (2H, s, CH@ ꢂ 2), 3.72
(6H, s, OMe ꢂ 2) and 1.49 (36H, s, CMe3); 13C NVR d 159.3, 143.7,
131.9, 127.7, 124.7, 64.2, 35.8 and 32.1. Anal. Calcd for C32H48O2:
C, 82.70; H, 10.41. Found: C, 82.91.69; H, 10.55.
5.3.1.5. 5-[(1E,3E)-4-(3-tert -Butyl-4-hydroxyphenyl)-1,3-buta-
dienyl]-1,3-benzenediol (7). Purification of the crude residue
by flash column chromatography (hexane/ether 80:20) afforded
stilbene 7 as a light brown solid (190 mg, 85%). Mp 153–156 °C.
1Y NVR (CD3OD) d 7.27 (1H, s, Ar–H), 7.15 (1H, d, J 8.0, Ar–H),
6.90–6.65 (2H, m, CH@ ꢂ 2), 6.69 (1H, d, J 8.0, Ar–H), 6.57 (1H, d,
J 15.0, CH@), 6.43 (1H, d, J 15.0, CH@), 6.39 (2H, s, Ar–H ꢂ 2),
6.15 (1H, s, Ar–H) and 1.40 (9H, s, CMe3); 13C NVR (CD3OD) d
159.6, 157.3, 141.3, 137.2, 134.7, 132.1, 130.9, 129.9, 126.9,
126.3, 125.8, 117.4, 105.7, 102.8, 35.5 and 29.9. MS (EI) m/z:
310.2 (M)+. Anal. Calcd for C20H22O3: C, 77.39; H, 7.14. Found: C,
77.36; H, 7.10.
5.3. General procedure for the cleavage of the methyl ether
5.3.1. Method A
To a solution of MeMgI [prepared under argon from Mg
(20 equiv) and MeI (20 equiv) in Et2O (1 mL/mmol)] was added
dropwise a solution of the methoxy stilbene derivative (14a–j)
(1 equiv) in Et2O (5 mL/mmol). The solvent was removed under
vacuum and the residue was then heated to 160 °C for 2 h under
argon. The cooled reaction mixture was then treated with NH4Cl
(satd solution) and extracted with Et2O. The combined organic ex-
tracts were washed with brine, dried and evaporated.
Compounds 3, 9 and 10 have already been described.21
5.3.1.6. 5-{(E)-2-[3,5-Di-tert-butyl-4-methoxyphenyl]ethenyl}-
1,3-benzenediol (15). Purification of the crude residue by flash
column chromatography (hexane/ether 80:20) afforded stilbene
15 as a light brown solid (520 mg, 56%). Mp 160–165 °C. 1Y NVR
d 7.38 (2H, s, Ar–H ꢂ 2), 7.02 (1H, d, J 16.0, CH@), 6.84 (1H, d, J
16.0, CH@), 6.58 (2H, d, J 2.0, Ar–H ꢂ 2), 6.27 (1H, t, J 2.0, Ar–H),
3.71 (3H, s, OMe) and 1.47 (18H, s, CMe3 ꢂ 2); 13C NVR d 159.5,
156.8, 143.9, 140.5, 131.2, 130.2, 126.4, 124.9, 106.0, 101.9, 64.3,
35.7 and 32.0. Anal. Calcd for C23H30O3: C, 77.93; H, 8.53. Found:
C, 77.88; H, 8.55.
5.3.1.1. 5-{(E )-2-[3-(1-Ethylpropyl)-4-hydroxyphenyl]ethenyl}-
1,3-benzenediol (1). Purification of the crude residue by flash
column chromatography (hexane/ether 80:20) afforded stilbene 1
as a yellow amorphous solid (54 mg, 44%). 1Y NVR (CD3OD) d
8.52 (1H, s, OH), 8.42 (2H, s, OH ꢂ 2), 7.31 (1H, d, J 2.0, Ar–H),
7.23 (1H, dd, J 8.5 and 2.0, Ar–H), 7.02 (1H, d, J 16.5, CH@), 6.87
(1H, d, J 16.5, CH@), 6.84 (1H, d, J 8.5, Ar–H), 6.53 (2H, d, J 2.0,
Ar–H ꢂ 2), 6.25 (1H, t, J 2, Ar–H), 3.00–2.75 (1H, m, CH(CH2Me)2),
1.75–1.55 (4H, m, CH(CH2Me)2) and 0.80 (6H, t, J 7.5, CH(CH2Me)2);
13C NVR (CD3OD) d 159.6, 156.8, 141.4, 133.0, 130.2, 129.9, 126.7,