d, J = 8.76 Hz), 8.71 (1H, d, J = 8.04 Hz), 11.49 ppm (1H, s,
d, J = 8.76 Hz), 8.64 (1H, d, J = 7.84), 12.50 ppm (1H, s, -NH).
-1
-1
˜
˜
-NH). IR (KBr): n = 3427, 2227 cm . Elemental analysis calcd
IR (ATR): n = 3240, 1692 cm . Elemental analysis calcd (%) for
(%) for C34H30N4O2 (526.63): C 77.54, H 5.74, N 10.64; found: C
77.51, H 5.71, N 10.60; 3a: decomposition 303–304 ◦C; 1H NMR
(acetone-d6, TMS): d = 1.03 (6H, t), 1.46-1.52 (4H, m), 1.70-1.78
(4H, m), 3.52 (4H, t), 7.01 (1H, dd, J = 2.20 and 9.04 Hz), 7.07
(1H, d, J = 2.20 Hz), 7.43 (1H, m), 7.54 (1H, m), 7.76 (1H, d, J =
8.20 Hz), 8.06 (2H, d, J = 8.32 Hz), 8.50 (2H, d, J = 8.32 Hz), 8.51
C34H31N3O4: C 74.84, H 5.73, N 7.70; found: C 74.◦72, H 5.63, N
1
7.67. FABMS m/z = 545 (M+); 3c: mp. 280–282 C; H NMR
(DMSO-d6, TMS) d = 1.06 (6H, t), 1.44-1.52 (4H, m), 1.67-1.73
(4H, m), 3.20-3.55 (4H, m) (overlapping peak of dissolved water
in DMSO-d6), 7.02 (1H, dd, J = 1.96 and 8.76 Hz), 7.14 (1H, d,
J = 1.96 Hz), 7.47 (1H, t), 7.60 (1H, t), 7.78 (1H, d, J = 8.80 Hz),
8.32 (2H, d, J = 8.80 Hz), 8.49 (2H, d, J = 7.84 Hz), 8.53 (1H, d,
J = 8.80 Hz), 8.72 (1H, d, J = 7.84 Hz), 12.53 ppm (1H, s, -NH).
(1H, d, J = 9.04 Hz), 8.74 (1H, d, J = 7.80 Hz), 11.49 ppm (1H, s,
-1
˜
-NH). IR (KBr): n = 3341, 2229 cm . Elemental analysis calcd
-1
+
˜
(%) for C34H30N4O2 (526.63): C 77.54, H 5.74, N 10.64; found: C
77.48, H 5.51, N 10.51.
IR (ATR): n = 3214, 1699 cm . FABMS m / z = 545 (M )
Preparation of 7-(4-pyridyl)-3-dibutylamino-benzofuro[2,3-
c]oxazolo[4,5-a]carbazole (2d) and 7-(4-pyridyl)-3-
dibutylamino-benzofuro[2,3-c]oxazolo[5,4-a]carbazole (3d)
Preparation of 7-(4-methoxycarbonylphenyl)-3-dibutylamino-
benzofuro[2,3-c]oxazolo[4,5-a]carbazole (2b) and
7-(4-methoxycarbonylphenyl)-3-dibutylamino-benzofuro[2,3-
c]oxazolo[5,4-a]carbazole (3b)
A solution of 1 (0.20 g, 0.48 mmol), p-cyanobenzaldehyde (0.052 g,
0.48 mmol), and ammonium acetate (0.75 g, 9.73 mmol) in acetic
acid (50 ml) was stirred at 90 ◦C for 2 h. After concentrating under
reduced pressure, the resulting residue was chromatographed on
silica gel (toluene–acetic acid = 5 : 1 as eluent) to give 2d (0.074 g,
yield 31%) as an orange powder and 3d (0.031 g, yield 12%) as an
orange powder; 2d: mp. 256–258 ◦C; 1H NMR (acetone-d6, TMS)
d = 1.03 (6H, t), 1.46-1.51 (4H, m), 1.70-1.76 (4H, m), 3.54 (4H,
t), 7.04 (1H, dd, J = 1.96 and 8.00 Hz), 7.07 (1H, d, J = 1.96 Hz),
7.42 (1H, t), 7.53 (1H, t), 7.82 (1H, d, J = 8.00 Hz), 8.23 (2H, d,
J = 6.80 Hz), 8.58 (1H, d, J = 8.00 Hz), 8.74 (1H, d, J = 8.00 Hz),
8.90 (2H, d, J = 6.80 Hz), 11.55 ppm (1H, s, -NH). IR (ATR):
A solution of 1 (0.20 g, 0.48 mmol), 4-formyl-benzoic acid methyl
ester (0.08 g, 0.48 mmol) and ammonium acetate (1.20 g, 15 mmol)
in acetic acid (35 ml) was stirred at 90 ◦C for 1 h. After the reaction
was complete, the reaction mixture was condensed. The resulting
precipitate was washed with water and dried. The residue was
chromatographed on silica gel (dichloromethane–hexane = 5 : 1
as eluent) to give 2b (0.16 g, yield 58%) as an orange powder
and ◦3b (0.08 g, yield 29%) as an orange powder; 2b: mp. 284–
1
285 C; H NMR (DMSO-d6, TMS) d = 1.00 (6H, t), 1.39-1.45
(4H, m), 1.61-1.66 (4H, m), 3.23-3.51 (4H, m) (overlapping peak
of dissolved water in DMSO-d6), 3.94 (3H, s), 6.99 (1H, dd, J =
1.96, 8.80 Hz), 7.08 (1H, d, J = 1.96 Hz), 7.40 (1H, t), 7.52 (1H, t),
7.69 (1H, d, J = 7,84 Hz), 8.26 (2H, d, J = 8.80 Hz), 8.44 (2H, d,
-1
+
˜
n = 3061, 1624, 1602 cm . FABMS m/z = 503 (M ); 3d: mp.
264–266 ◦C; 1H NMR (DMSO-d6, TMS) d = 1.00 (6H, t), 1.39-
1.46 (4H, m), 1.60-1.67 (4H, m), 3.20-3.48 (4H, m) (overlapping
peak of dissolved water in DMSO-d6), 6.96 (2H, dd, J = 2.20 and
8.00 Hz), 7.09 (1H, d, J = 2.20 Hz), 7.43 (1H, t), 7.54 (1H, t), 7.73
(1H, d, J = 8.00 Hz), 8.20 (2H, d), 8.48 (1H, d, J = 8.80 Hz), 8.66
(1H, d, J = 8.80 Hz), 8.93 (2H, d), 11.55 ppm (1H, s, -NH). IR
J = 8.80 Hz), 8.49 (1H, d, J = 8.80 Hz), 8.63 (1H, d, J = 8.80 Hz),
-1
˜
12.53 ppm (1H, s, -NH). IR (ATR): n = 3361, 1705 cm . FABMS
m/z = 559 (M+); 3b: mp. 273–275 ◦C; 1H NMR (DMSO-d6, TMS)
d = 1.00 (6H, t), 1.44 (4H, m), 1.65 (4H, m), 3.25-3.51 (4H, m),
(overlapping peak of dissolved water in DMSO-d6), 3.94 (3H, s),
6.97 (1H, d, J = 8.76), 7.07 (1H, s), 7.41 (1H, t), 7.55 (1H, t), 7.72
(1H, d, J = 7.80 Hz), 8.28 (2H, d, J = 7.80 Hz), 8.46 (2H, d, J =
-1
+
˜
(ATR): n = 3095, 1602, 1559 cm . FABMS m/z = 503 (M ).
Preparation of 7-phenyl-3-dibutylamino-benzofuro[2,3-
c]oxazolo[4,5-a]carbazole (2e) and 7-phenyl-3-dibutylamino-
benzofuro[2,3-c]oxazolo[5,4-a]carbazole (3e)
7.80 Hz), 8.48 (1H, d, J = 7.84), 8.66 (1H, d, J = 7.84), 11.51 ppm
-1
˜
(1H, s, -NH). IR (ATR): n = 3214, 1699 cm . FABMS m/z =
559 (M+).
A solution of 1 (0.30 g, 0.72 mmol), benzaldehyde (0.08 g,
0.72 mmol) and ammonium acetate (1.67 g, 21.7 mmol) in acetic
acid (40 ml) was stirred at 90 ◦C for 1 h. After concentrating
under reduced pressure, the resulting residue was purified by
chromatography on silica gel (dichloromethane–hexane = 7 : 1 as
eluent) to give 2e (0.31 g, yield 52%) as a light yellow powder and
3e (0.10 g, yield 17%) also as a light yellow powder; 2e: mp. 197–
Preparation of 7-(4-carboxyphenyl)-3-dibutylamino-benzofuro[2,3-
c]oxazolo[4,5-a]carbazole (2c) and 7-(4-carboxyphenyl)-3-
dibutylamino-benzofuro[2,3-c]oxazolo[5,4-a]carbazole (3c)
A solution of 1 (0.50 g, 1.21 mmol), 4-formyl-benzoic acid (0.18 g,
, 1.21 mmol) and ammonium acetate (2.79 g, 36.1 mmol) in acetic
acid (70 ml) was stirred at 90 ◦C for 1.5 h. After the reaction
was complete, the reaction mixture was condensed. The resulting
precipitate was washed with water and dried. The residue was
chromatographed on silica gel (dichloromethane–hexane = 5 : 1
as eluent) to give 2c (0.22 g, yield 33%) as a dark orange powder
and ◦3c (0.05 g, yield 5%) also as an orange powder; 2c: mp. 296–
◦
1
198 C; H NMR (acetone-d6, TMS) d = 1.03 (6H, t), 1.46-1.52
(4H, m), 1.70-1.76 (4H, m), 3.53 (4H, t), 7.03 (1H, dd, J = 1.96
and 8.80 Hz), 7.06 (1H, d, J = 1.96 Hz), 7.40 (1H, t), 7.51 (1H, t),
7.67 (3H, m), 7.81 (1H, d, J = 7.80 Hz), 8.38 (2H, dd, J = 1.96
and 7.80 Hz), 8.56 (1H, d, J = 8.80 Hz), 8.72 (1H, d, J = 7.84 Hz),
-1
˜
11.42 ppm (1H, s, -NH). IR (ATR): n = 3572, 1623 cm . FABMS
1
297 C; H NMR (DMSO-d6, TMS) d = 1.00 (6H, t), 1.39-1.46
m/z = 501 (M+); 3e: mp. 174–175 ◦C; 1H NMR (acetone-d6, TMS)
d = 1.03 (6H, t), 1.46-1.52 (4H, m), 1.69-1.74 (4H, m), 3.52 (4H,
t), 7.02 (1H, dd, J = 1.96 and 8.76 Hz), 7.08 (1H, d, J = 1.96 Hz,
7.44 (1H, t), 7.53 (1H, t), 7.66 (3H, m), 7.78 (1H, d, J = 8.80 Hz),
8.37 (2H, dd, J = 2.92 and 6.84), 8.52 (1H, d, J = 8.80 Hz), 8.74
(4H, m), 1.60-1.67 (4H, m), 3.23-3.65 (4H, m) (overlapping peak
of dissolved water in DMSO-d6), 6.99 (1H, dd, J = 1.96, 8.80 Hz),
7.08 (1H, d, J = 1.96), 7.40 (1H, t), 7.51 (1H, t), 7.70 (1H, d, J =
7.80 Hz), 8.22 (2H, d, J = 7.84), 8.39 (2H, d, J = 7.84), 8.50 (1H,
2768 | Org. Biomol. Chem., 2010, 8, 2756–2770
This journal is
The Royal Society of Chemistry 2010
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