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K. Yamamura et al. / Tetrahedron 58 (2002) 7653–7661
ring), 7.52 (1H, d, J¼5.3 Hz, thiophene ring), 8.85–9.11
(6H, m, tropylium). Anal. calcd for C16H13BF4OS: C, 56.50;
H, 3.85. Found: C, 56.72; H, 3.68.
membered ring); m/z: 294 (Mþ). Anal. calcd for C19H18OS:
C, 77.51; H, 6.16. Found: C, 77.43; H, 6.25.
4.8.4. 1-(4-Azuleno[1,2-b]thienyl)-3-phenyl-prop-1-en-3-
one (1d). 1-(4-Azuleno[1,2-b]thienyl)-3-phenyl-prop-1-en-
3-one (1d) was obtained from 3d as deep bluish-green
needles in 52% yield. Mp 224.5–225.58C. 1H NMR
(CDCl3): d 7.31–7.39 (2H, m, seven-membered ring),
7.52–7.65 (4H, m, phenyl and seven-membered ring), 7.72
(1H, d, J¼15.0 Hz, olefin), 7.85 (1H, d, J¼5.1 Hz,
thiophene ring), 7.96 (1H, d, J¼5.1 Hz, thiophene ring),
8.11 (2H, dd, J¼8.0, 1.7 Hz, phenyl), 8.38 (1H, d, J¼
9.1 Hz, seven-membered ring), 8.67 (1H, d, J¼15.0 Hz,
olefin), 8.70 (1H, d, J¼10.4 Hz, seven-membered ring);
m/z: 314 (Mþ). Anal. calcd for C21H14OS: C, 80.23; H, 4.49.
Found: C, 80.15; H, 4.58.
4.7.3. 2-(5-Phenyl-3-furyl)-3-tropyliothiophene tetra-
fluoroborate (4c). 2-(5-Phenyl-3-furyl)-3-tropyliothio-
phene tetrafluoroborate (4c) was obtained as violet powder
in 72% yield. 1H NMR (CD3CN): d 6.82 (1H, d, J¼3.7 Hz,
furan ring), 6.89 (1H, d, J¼3.7 Hz, furan ring), 7.25–7.38
(5H, m, phenyl), 7.43 (1H, d, J¼5.3 Hz, thiophene ring),
7.68 (1H, d, J¼5.3 Hz, thiophene ring), 8.85–8.97 (4H,
m, tropylium), 9.18–9.24 (2H, m, tropylium). Anal. calcd
for C21H15BF4OS: C, 62.71; H, 3.76. Found: C, 62.58; H,
3.58.
4.8. General procedure for the synthesis of b-(4-azu-
leno[1,2-b]thienyl)-a,b-unsaturated ketones (1) and
b-(4-azuleno[2,1-b]thienyl)-a,b-unsaturated ketones (2)
4.8.5. 1,1,1-Triphenyl-4-(4-azuleno[1,2-b]thienyl)but-3-
en-2-one (1e). 1,1,1-Triphenyl-4-(4-azuleno[1,2-b]thienyl)-
but-3-en-2-one (1e) was obtained from 3e as deep bluish-
green needles in 42% yield. Mp .3008C. 1H NMR (CDCl3):
6.88 (1H, d, J¼15.2 Hz, olefin), 6.95 (1H, d, J¼5.1 Hz,
thiophene ring), 7.21–7.42 (17H, m, phenyl and seven-
membered ring), 7.60 (1H, dd, J¼9.8, 9.8 Hz, seven-
membered ring), 7.72 (1H, d, J¼5.1 Hz, thiophene ring),
8.31 (1H, d, J¼9.0 Hz, seven-membered ring), 8.50 (1H,
d, J¼15.2 Hz, olefin), 8.60 (1H, d, J¼10.3 Hz, seven-
membered ring); m/z: 480 (Mþ). Anal. calcd for C34H24OS:
C, 84.97; H, 5.03. Found: C, 85.15; H, 4.88.
A solution of 3 or 4 (1.00 mmol) in 100 mL of dry CH2Cl2
was refluxed, and the solvent was evaporated in vacuo. The
product was purified by column chromatography over silica
gel and recrystallized from toluene.
4.8.1. 4-(4-Azuleno[1,2-b]thienyl)but-3-en-2-one (1a).
4-(4-Azuleno[1,2-b]thienyl)but-3-en-2-one
(1a)
was
obtained from 3a as deep-bluish green needles in 57%
yield; without isolation of 3a, 1a was also obtained
0
1
immediately from 7a in 36% yield. Mp 144–145.58C. H
NMR (CDCl3): d 2.46 (3H, s, CH3), 6.90 (1H, d, J¼15.6 Hz,
olefin), 7.25 (1H, dd, J¼10.4, 9.6 Hz, seven-membered
ring), 7.26 (1H, dd, J¼10.1, 9.2 Hz, seven-membered ring),
7.62 (1H, dd, J¼10.1, 9.6 Hz, seven-membered ring), 7.73
(1H, d, J¼5.1 Hz, thiophene ring), 7.89 (1H, d, J¼5.1 Hz,
thiophene ring), 8.28 (1H, d, J¼15.6 Hz, olefin), 8.29 (1H,
d, J¼9.2 Hz, seven-membered ring), 8.49 (1H, d, J¼
10.4 Hz, seven-membered ring); m/z: 252 (Mþ). Anal.
calcd for C16H12OS: C, 76.16; H, 4.79. Found: C, 76.30; H,
4.63.
4.8.6. 1-(4-Azuleno[1,2-b]thienyl)-5-phenyl-penta-1,4-
dien-3-one (1h). 1-(4-Azuleno[1,2-b]thienyl)-5-phenyl-
pent-1,4-dien-3-one (1h) was obtained from 3h-(E) or
3h-(Z) as deep-green needles in 54% yield from 3h-(E),
65% from 3h-(Z). Mp 176–1778C. 1H NMR (CDCl3): 7.17
(1H, d, J¼15.9 Hz, olefin), 7.23 (1H, d, J¼15.3 Hz, olefin),
7.29–7.41 (5H, m, phenyl and seven-membered ring), 7.66
(2H, d, J¼7.8 Hz, phenyl), 7.64 (1H, t, J¼9.5 Hz, seven-
membered ring), 7.79 (1H, d, J¼15.9 Hz, olefin), 7.84 (1H,
d, J¼5.1 Hz, thiophene ring), 7.94 (1H, d, J¼5.1 Hz,
thiophene ring), 8.37 (1H, d, J¼9.1 Hz, seven-membered
ring), 8.57 (1H, d, J¼15.3 Hz, olefin), 8.69 (1H, d, J¼
10.3 Hz, seven-membered ring); m/z: 340 (Mþ). Anal. calcd
for C23H16OS: C, 81.15; H, 4.74. Found: C, 81.33; H, 4.82.
4.8.2. 5-(4-Azuleno[1,2-b]thienyl)pent-4-en-3-one (1b).
5-(4-Azuleno[1,2-b]thienyl)pent-1-en-3-one (1b) was
obtained from 3b as dark-green needles in 47% yield. Mp
1
1278C. H NMR (CDCl3): d 1.25 (3H, t, J¼7.4 Hz, CH3),
2.77 (2H, q, J¼7.4 Hz, CH2), 6.96 (1H, d, J¼15.5 Hz,
olefin), 7.31 (2H, t, J¼9.9 Hz, seven-membered ring), 7.62
(1H, t, J¼9.9 Hz, seven-membered ring), 7.78 (1H, d,
J¼5.1 Hz, thiophene ring), 7.92 (1H, d, J¼5.1 Hz, thio-
phene ring), 8.38 (1H, d, J¼7.1 Hz, seven-membered ring),
8.39 (1H, d, J¼15.5 Hz, olefin), 8.62 (1H, d, J¼10.5 Hz,
seven-membered ring); m/z: 266 (Mþ). Anal. calcd for
C17H14OS: C, 76.66; H, 5.30. Found: C, 76.48; H, 5.38.
4.8.7. 1,1,1-Triphenyl-4-(4-azuleno[2,1-b]thienyl)but-3-
en-2-one (2a). 1,1,1-Triphenyl-4-(4-azuleno[2,1-b]thienyl)-
but-3-en-2-one (2a) was obtained from 4a as deep-green
1
needles in 52% yield. Mp 283–2858C. H NMR (CDCl3):
6.77 (1H, d, J¼14.9 Hz, olefin), 7.16–7.62 (19H, m, phenyl,
seven-membered and thiophene ring), 7.68 (1H, d, J¼
5.2 Hz, thiophene ring), 8.42 (1H, d, J¼9.0 Hz, seven-
membered ring), 8.51 (1H, d, J¼14.9 Hz, olefin), 8.60 (1H,
d, J¼10.3 Hz, seven-membered ring); m/z: 480 (Mþ). Anal.
calcd for C34H24OS: C, 84.97; H, 5.03. Found: C, 84.76; H,
5.16.
4.8.3. 1-(4-Azuleno[1,2-b]thienyl)-4,4-dimethyl-pent-1-
en-3-one (1c). 1-(4-Azuleno[1,2-b]thienyl)-4,4-dimethyl-
pent-1-en-3-one (1c) was obtained from 3c as deep bluish-
green needles in 48% yield. Mp 1268C. 1H NMR (CDCl3): d
1.32 (9H, s, CH3), 7.22 (2H, t, J¼9.8 Hz, seven-membered
ring), 7.28 (1H, d, J¼15.2 Hz, olefin), 7.54 (1H, t, J¼
10.1 Hz, seven-membered ring), 7.70 (1H, d, J¼5.1 Hz,
thiophene ring), 7.89 (1H, d, J¼5.1 Hz, thiophene ring),
8.26 (1H, d, J¼9.1 Hz, seven-membered ring), 8.46 (1H,
d, J¼15.1 Hz, olefin), 8.57 (1H, d, J¼10.6 Hz, seven-
4.8.8. 4-(4-Azuleno[2,1-b]thienyl)but-3-en-2-one (2b).
4-(4-Azuleno[2,1-b]thienyl)but-3-en-2-one (2b) was obtained
from 3a as deep bluish-green prisms in 54% yield. Mp 151–
1528C. 1H NMR (CDCl3): d 2.47 (3H, s, CH3), 6.73
(1H, d, J¼15.5 Hz, olefin), 7.36 (1H, dd, J¼10.4, 9.6 Hz,
seven-membered ring), 7.38 (1H, dd, J¼10.0, 9.3 Hz,