C.-F. Chou et al. / Tetrahedron 62 (2006) 8467–8473
8471
a yellow residue, which was purified by column chroma-
tography using THF/n-hexane as eluent and followed by
recrystallization from CH2Cl2 and MeOH.
4.3.1. Compound (Ia). Yellow solid, yield 25% (250 mg).
Mp: 285 ꢁC (decomp.). IR (KBr): nmax 3045 m, 2910 w,
2115 w cmꢀ1
.
1H NMR (CDCl3): d 8.13 (d, J¼8.3 Hz,
4H), 8.05 (d, J¼8.0 Hz, 4H), 7.66 (d, J¼8.3 Hz, 4H), 7.54
(d, J¼8.0 Hz, 4H), 7.27 (s, 2H), 1.36 (s, 18H). 13C NMR
(CDCl3): d 31.10, 35.12, 86.52, 95.02, 97.10, 112.10,
112.85, 114.80, 125.45, 126.10, 126.29, 126.82, 128.29,
132.41, 132.98, 155.57. FABMS (m/z): 922 (M+). HRMS
Calcd for C48H36Br2N4O2S2: 922.0646. Found: 922.0626.
Anal. Calcd for C48H36Br2N4O2S2: C, 62.34; H, 3.92; N,
6.06. Found: C, 62.21; H, 3.87; N, 6.12.
4.2.1. Compound (1). Orange solid, yield 62% (360 mg).
Mp: 333–335 ꢁC. IR (KBr): nmax 3055 w, 2930 w, 2130
1
w cmꢀ1. H NMR (CDCl3): d 8.17–8.13 (m, 8H), 8.04 (d,
J¼7.8 Hz, 8H), 7.77 (d, J¼8.0 Hz, 4H), 7.67 (d, J¼7.8 Hz,
4H), 7.53 (d, J¼8.0 Hz, 8H), 7.41 (s, 2H), 1.35 (s, 36H).
13C NMR (CDCl3): d 31.11, 35.11, 84.49, 87.74, 95.09,
96.05, 119.61, 120.87, 121.96, 123.90, 125.56, 126.10,
126.82, 126.90, 131.96, 132.03, 135.48, 139.06, 155.52,
155.57, 163.73, 164.90. FAB MS (m/z): 1367 (M++H).
HRMS Calcd for C88H71N8O4S2: 1367.5040. Found:
1367.5033. Anal. Calcd for C88H70N8O4S2: C, 77.28; H,
5.16; N, 8.19. Found: C, 76.90; H, 5.22; N, 8.01.
4.3.2. Compound (Ib). Yellow solid, yield 60% (840 mg).
Mp: 253 ꢁC (decomp.). IR (KBr): nmax 3046 m, 2200 w,
1
2120 cmꢀ1. H NMR (CDCl3): d 7.61 (d, J¼7.8 Hz, 4H),
7.51 (d, J¼7.8 Hz, 4H), 7.02 (s, 2H). 13C NMR (CDCl3):
d 90.57, 90.79, 111.20, 112.04, 114.76, 117.99, 127.96,
132.59, 132.93, 133.35. FABMS (m/z): 571 (M+). HRMS
Calcd for C26H10Br2N2S2: 571.8652. Found: 571.8632.
Anal. Calcd for C26H10Br2N2S2: C, 54.37; H, 1.76; N,
4.88. Found: C, 54.86; H, 1.72; N, 4.64.
4.2.2. Compound (2). Orange solid, yield 20% (350 mg).
Mp: 246 ꢁC (decomp.). IR (KBr): nmax 3058 w,
1
2130 cmꢀ1. H NMR (CDCl3): d 7.88 (t, J¼9.6 Hz, 4H),
7.79 (t, J¼9.0 Hz, 4H), 7.68–7.63 (m, 4H), 7.52–7.44 (m,
8H), 7.42–7.33 (m, 12H), 7.21–7.17 (m, 12H), 7.15 (s,
2H), 7.10 (t, J¼6.7 Hz, 8H), 7.01 (t, J¼7.6 Hz, 4H),
6.91–6.83 (m, 8H). 13C NMR (CDCl3): d 84.24, 86.67,
95.12, 96.49, 115.85, 117.36, 120.47, 121.78, 122.96,
125.65, 125.99, 126.08, 127.71, 128.28, 128.76, 129.32,
132.10, 132.96, 134.66, 138.72, 144.72. FABMS (m/z):
1434 (M+). HRMS Calcd for C104H66N4S2: 1434.4729.
Found: 1434.4740. Anal. Calcd for C104H66N4S2: C,
87.00; H, 4.63; N, 3.90. Found: C, 87.11; H, 4.90; N, 3.82.
4.4. General procedures for the synthesis of
compounds 4–6
Compounds 3,30-tetrakis-p-tolylethynyl-5,50-2-(4-tert-butyl-
phenyl)-5-(4-ethynyl-phenyl)-[1,3,4]oxadiazole-[2,20]-
bithiophene (4), 4,40-(3,30-bis((4-(naphthalen-1-yl(phenyl)-
amino)phenyl)ethynyl)-2,20-bithiophene-5,50-diyl)bis(ethyne-
2,1-diyl)dibenzonitrile (5), and 4,40-(3,30-bis(p-tolyl-
ethynyl)-2,20-bithiophene-5,50-diyl)bis(ethyne-2,1-diyl)di-
benzonitrile (6) were synthesized by a similar procedure as
the following description. To a flask containing dibromo-
compounds (Ia or Ib) (1 equiv), PdCl2(PPh3)2 (3 mmol %
per bromo atom), CuI (1 mmol % per bromo atom), PPh3
(3 mmol % per bromo atom), and aromatic acetylene
(2.2 equiv per halogen atom) was added i-Pr2NH (100 mL).
The resulting mixture was stirred at room temperature for
30 min, allowed to reflux for two days. The solvent was
removed under vacuum, and the residue was extracted
with CH2Cl2 and brine. Removal of CH2Cl2 provided an
orange-red residue, which was purified by column chroma-
tography using THF/n-hexane as eluent and followed by
recrystallization from CH2Cl2 and MeOH.
4.2.3. Compound (3). Yellow solid, yield 80% (1.02 g). Mp:
225–227 ꢁC. IR (KBr): nmax 3055 w, 2930 w, 2130 w cmꢀ1
.
1H NMR (CDCl3): d 7.50 (s, J¼8.1 Hz, 4H), 7.4 (s,
J¼8.0 Hz, 4H), 7.27 (s, 2H), 7.19 (d, J¼7.9 Hz, 4H), 7.15
(d, J¼8.0 Hz, 4H), 2.37 (s, 6H), 2.35 (s, 6H). 13C NMR
(CDCl3): d 21.58, 81.50, 84.72, 92.62, 95.37, 96.61,
119.56, 119.97, 122.05, 129.19, 129.28, 131.42, 134.63,
138.08, 138.96. FABMS (m/z): 622 (M+). HRMS Calcd for
C44H30S2: 622.1789. Found: 622.1790. Anal. Calcd for
C44H30S2: C, 84.85; H, 4.85. Found: C, 84.47; H, 5.02.
4.3. General procedures for the synthesis of
dibromo-substituted compounds
4.4.1. Compound (4). Orange solid, yield 30% (113 mg).
Mp: 325 ꢁC (decomp.). IR (KBr): nmax 3055 w, 2930 w,
Compounds 3,30-dibromo-5,50-2-(4-tert-butyl-phenyl)-5-
(4-ethynyl-phenyl)-[1,3,4]oxadiazole-[2,20]bithiophene (Ia)
and 4,40-(3,30-dibromo-2,20-bithiophene-5,50-diyl)bis(ethyne-
2,1-diyl)-dibenzonitrile (Ib) were synthesized by a similar
procedure as the following description. To a flask containing
3,5,30,50-tetrabromo-[2,20]bithiophene(1 equiv),PdCl2(PPh3)2
(1.5 mmol % per bromo atom), CuI (0.5 mmol % per bromo
atom), PPh3 (1.5 mmol % per bromo atom), and aromatic
acetylene (2.2 equiv per halogen atom) was added i-Pr2NH
(70 mL). The resulting mixture was stirred at room temper-
ature for 5 h, then heated to 40 ꢁC for 5 h and allowed to
reflux for one day. The solvent was removed under vacuum,
and the residue was extracted with CH2Cl2 and brine. Re-
moval of CH2Cl2 provided an orange residue, which was
purified by column chromatography using THF/n-hexane
as eluent and followed by recrystallization from CH2Cl2
and MeOH.
2130 w cmꢀ1
.
1H NMR (CDCl3): d 8.02 (d, J¼8.0 Hz,
4H), 8.01 (d, J¼7.8 Hz, 4H), 7.68 (d, J¼7.6 Hz, 4H), 7.64
(d, J¼8.0 Hz, 4H), 7.52 (d, J¼7.8 Hz, 4H), 7.24 (d, J¼
7.6 Hz, 4H), 7.00 (s, 2H), 2.41 (s, 6H), 1.35 (s, 18H). 13C
NMR (CDCl3): d 21.42, 31.08, 35.08, 85.76, 89.14, 95.01,
97.41, 112.06, 114.78, 120.85, 125.27, 126.08, 126.27,
126.80, 128.19, 128.26, 129.00, 132.96, 137.81, 155.53.
FABMS (m/z): 995 (M++H). HRMS Calcd for
C66H51N4O2S2: 995.3453. Found: 995.3455. Anal. Calcd
for C66H50N4O2S2: C, 79.65; H, 5.06; N, 5.63. Found: C,
79.90; H, 5.11; N, 5.81.
4.4.2. Compound (5). Orange solid, yield 40% (226 mg).
Mp: 242 ꢁC (decomp.). IR (KBr): nmax 3055 w, 2200 w,
2150 w cmꢀ1
.
1H NMR (CDCl3): d 7.89 (dd, J¼3.1,
8.2 Hz, 4H), 7.80 (d, J¼8.2 Hz, 2H), 7.58 (d, J¼8.0 Hz,