T. Kawai et al.
FULL PAPERS
1-Hexyl-4-vinylbenzene (4)
12H), 0.90 ppm (m, 6H); 13C NMR (75 MHz, CD2Cl2, TMS): d=149.7,
147.9, 145.5, 144.8, 143.4, 143.1, 140.5, 139.7, 138.3, 135.8, 134.0, 132.3,
132.2, 131.8, 129.8, 129.5, 129.4, 128.7, 128.5, 128.4, 127.1, 126.3, 125.9,
125.6, 124.3, 124.3, 123.8, 123.7, 122.9, 119.3, 118.0, 36.0, 36.0, 35.3, 35.3,
32.2, 31.9, 29.4, 23.1, 14.3 ppm; HRMS (ESI): m/z: calcd for C50H50N2S3:
775.3214 [M+H]+; found: 775.3231.
A mixture of 1-bromo-4-hexylbenzene (1.3 g, 5.3 mmol), tributylvinyltin
(1.7 g, 5.5 mmol), and anhydrous DMF (60 mL) was degassed with N2 for
30 min. Then, [PdACHTUNGTRENNUNG(PPh3)4] (0.32 g, 0.27 mmol) was added to the reaction
mixture and it was stirred for 3.5 h at 908C. After the mixture had been
quenched by the addition of NH4Cl solution, it was extracted with n-
hexane and the combined organic layer was dried over MgSO4 and fil-
tered. Potassium fluoride was added to the filtrate and the mixture
stirred for 5 h. After the solvent had been removed, the crude product
was purified by silica gel column chromatography by using n-hexane as
the eluent to yield 4 (0.56 g, 56%) as a clear oil. Rf =0.5 (n-hexane);
1H NMR (300 MHz, CD2Cl2, TMS): d=7.33–7.31 (m, 2H), 7.15–7.13 (m,
2H), 6.68 (t, 1H), 5.70 (d, 1H), 5.18 (d, 1H), 2.59 (t, 2H), 1.54 (m, 2H),
1.30 (m, 6H), 0.88 ppm (m, 3H).
4,7-Bis[(4-hexylphenyl)ethynyl]-1-methyl-2-(5-phenylthiophen-2-yl)-1H-
benzo[d]imidazole (EBIm)
A
mixture of 7 (0.45 g, 1.0 mmol), CuI (0.012 g, 0.063 mmol), PPh3
(0.031 g, 0.12 mmol), triethylamine (9 mL), and anhydrous THF (3 mL)
was degassed with N2 for 30 min. Then, [PdCl2A(PPh3)2] (0.059 g,
0.084 mmol), (0.67 g, 2.6 mmol) and tetrabutylammonium fluoride
CTHUNGTRENNUNG
3
(TBAF) (in THF 1m, 2 mL) were added to the mixture. The resulting
mixture was stirred overnight at 708C and then quenched by the addition
of water. The reaction mixture was extracted with dichloromethane and
the combined organic solution was washed with saturated brine, dried
over MgSO4, filtered, and concentrated. The crude product was purified
with alumina column chromatography by using ethyl acetate/n-hexane
(1:5) as the eluent. The separated product was further purified by recy-
cling preparative GPC (chloroform) and normal-phase HPLC (chloro-
3,6-Dibromobenzene-1,2-diamine (5)
NaBH4 (3.4 g, 90 mmol) was added portionwise to a dried four-neck
round-bottomed flask charged with 4,7-dibromobenzo[c]ACTHUNRTGNEUNG[1,2,5]thiadiazole
(3.0 g, 10 mmol) in anhydrous ethanol (100 mL) under a N2 atmosphere
at 08C. The mixture was stirred at room temperature for 13 h. After the
consumption of reactant was confirmed by TLC analysis, the solvent was
removed. Water was added to the residue, which was extracted with ethyl
acetate. The combined organic layer was dried over MgSO4 to yield 5
form/n-hexane) to yield EBIm (0.41 g, 61%) as
a yellow powder.
1H NMR (500 MHz, CD2Cl2, TMS): d=7.74–7.73 (m, 2H), 7.63 (d, 1H),
7.58–7.56 (m, 2H), 7.51–7.50 (m, 2H), 7.47–7.46 (m, 1H), 7.45–7.43 (m,
2H), 7.42 (s, 2H), 7.38–7.35 (m, 1H), 7.25–7.23 (m, 4H), 4.48 (s, 3H),
2.67–2.64 (m, 4H), 1.64 (m, 4H), 1.33 (m, 12H), 0.90 ppm (m, 6H);
13C NMR (75 MHz, CD2Cl2, TMS): d=149.6, 148.1, 144.8, 144.4, 144.3,
135.8, 133.9, 132.0, 131.6, 131.5, 130.0, 129.5, 129.1, 129.0, 128.8, 128.1,
126.6, 126.4, 124.3, 120.7, 120.3, 115.1, 107.4, 96.0, 95.7, 86.5, 85.6, 36.3,
34.0, 32.1, 31.7, 31.7, 29.4, 29.4, 23.0, 14. 3 ppm; HRMS (ESI): m/z: calcd
for C46H46N2S: 659.3460 [M+H]+; found: 659.3427.
(2.5 g, 93%) as
a white solid. Rf =0.5 (ethyl acetate/n-hexane 1:3);
1H NMR (300 MHz, CD2Cl2, TMS): d=6.83 (s, 2H), 3.89 ppm (brs, 4H).
4,7-Dibromo-2-(5-phenylthiophen-2-yl)-1H-benzo[d]imidazole (6)
A
mixture of 5 (2.5 g, 9.2 mmol), 5-phenylthiophene-2-carbaldehyde
(2.0 g, 11 mmol), p-toluenesulfonic acid monohydrate (0.17 g, 0.99 mmol)
and anhydrous ethanol (50 mL) was refluxed for 24 h under a N2 atmos-
phere. The reaction was quenched by the addition of water and ethyl ace-
tate. The organic layer was separated and dried over MgSO4. After re-
moval of the solvent, the product was washed with diethyl ether several
times to yield 6 (1.8 g, 46%) as a brown powder. Rf =0.5 (ethylacetate/n-
4,7-Bis(4-hexylstyryl)-1-methyl-2-(5-phenylthiophen-2-yl)-1H-
benzo[d]imidazole (VBIm)
A mixture of 7 (0.56 g, 1.2 mmol), 4 (0.53 g, 2.8 mmol), triethylamine
(0.5 mL), and anhydrous DMF (10 mL) was degassed with N2 for 30 min.
Then, PdACHTUNTRGENNUG(OAc)2 (0.11 g, 0.49 mmol) and PACHTUNGTRNEN(NGU oTol)3 (0.20 g, 0.66 mmol)
1
hexane 1:3); H NMR (300 MHz, [D6]DMSO, TMS): d=13.48 (brs, 1H),
8.15 (d, J=4.2 Hz, 1H), 7.79–7.76 (m, 2H), 7.65 (d, J=3.9 Hz, 1H), 7.46
(t, 1H), 7.39–7.32 ppm (m, 4H).
were added to the solution. The resulting mixture was stirred overnight
at 1208C and then quenched by the addition of water. The reaction mix-
ture was extracted with chloroform and the combined organic layer was
washed with saturated brine, dried over MgSO4, filtered, and concentrat-
ed. The crude product was purified with alumina column chromatography
by using ethyl acetate/n-hexane (1:5) as an eluent. The separated product
was further purified by recycling preparative GPC (chloroform) and
normal-phase HPLC (chloroform/n-hexane) to yield VBIm (0.13 g, 16%)
4,7-Dibromo-1-methyl-2-(5-phenylthiophen-2-yl)-1H-benzo[d]imidazole
(7)
Compound 6 (1.8 g, 4.0 mmol), K2CO3 (1.7 g, 12 mmol), methyliodide
(0.50 mL, 8.0 mmol), and anhydrous ethanol (30 mL) were added to a
dried four-neck round-bottomed flask. After the reaction mixture had
been stirred for 1 h, the solvent was evaporated and the resulting residue
was washed with water, n-hexane, and diethyl ether several times to yield
1
as a yellow powder. H NMR (500 MHz, CD2Cl2, TMS): d=7.88–7.84 (d,
7
(1.6 g, 89%) as a brown powder. Rf =0.8 (chloroform); 1H NMR
1H), 7.77–7.75 (m, 1H), 7.74–7.73 (m, 2H), 7.71–7.68 (m, 1H), 7.59–7.57
(d, 2H), 7.55–7.54 (m, 1H), 7.50–7.49 (d, 2H), 7.47 (m, 2H), 7.46 (s, 2H),
7.44 (m, 1H), 7.38–7.35 (m, 1H), 7.24–7.21 (m, 4H), 7.10–7.07ACHTUNGTRENNUNG(d, 1H),
4.24 (s, 3H), 2.65–2.62 (m, 4H), 1.63 (m, 4H), 1.33 (m, 12H), 0.90 ppm
(m, 6H); 13C NMR (75 MHz, CD2Cl2, TMS): d=149.0, 147.6, 143.5,
143.1, 142.0, 135.9, 135.2, 135.1, 134.0, 132.2, 131.5, 131.1, 129.7, 129.5,
129.2, 129.1, 128.6, 128.3, 127.0, 126.8, 126.3, 124.2, 124.2, 123.3, 123.1,
122.1, 120.7, 36.1, 36.1, 35.7, 32.2, 31.9, 30.1, 29.5, 29.4, 23.1, 14.3 ppm;
HRMS (ESI): m/z: calcd for C46H50N2S: 663.3773 [M+H]+; found:
663.3765.
(300 MHz, [D6]DMSO, TMS): d=7.83 (m, 3H), 7.74 (m, 1H), 7.49 (m,
2H), 7.42 (m, 3H), 4.29 ppm (s, 3H); 13C NMR (75 MHz, [D6]DMSO,
TMS): d=149.8, 147.2, 142.6, 133.6, 132.8, 131.4, 129.9, 129.4, 128.7,
128.4, 126.4, 125.8, 124.9, 111.8, 102.3, 34.72 ppm; HRMS (ESI): m/z:
calcd for C18H12Br2N2S: 448.9146 [M+H]+; found: 448.9131.
4,7-Bis[5-(4-hexylphenyl)thiophen-2-yl]-1-methyl-2-(5-phenylthiophen-2-
yl)-1H-benzo[d]imidazole (TBIm)
A mixture of 7 (0.29 g, 0.64 mmol), 2 (1.0 g, 2.7 mmol), 2m Na2CO3 solu-
tion (30 mL), and THF (40 mL) was degassed with N2 for 30 min. Then,
[PdACHTUNGTRENNUNG(PPh3)4] (0.080 g, 0.069 mmol) was added to the mixture. The resulting
mixture was stirred overnight at 908C. The reaction mixture was extract-
ed with ethyl acetate and the combined organic layer was dried over
MgSO4, filtered, and concentrated. The crude product was purified with
alumina column chromatography by using ethyl acetate/n-hexane (1:5) as
the eluent. The separated product was further purified by preparative
GPC (chloroform) and normal-phase HPLC (chloroform/n-hexane) to
yield TBIm (0.22 g, 44%) as a yellow powder. 1H NMR (500 MHz,
CD2Cl2, TMS): d=8.22 (d, 1H), 7.75–7.74 (m, 2H), 7.66–7.64 (m, 2H),
7.63 (m, 1H), 7.61–7.59 (m, 2H), 7.58 (m, 1H), 7.47 (m, 2H), 7.45 (m,
Acknowledgements
The authors thank S. Katao, Y. Nishiyama, and Y. Kajiki for their assis-
tance in X-ray crystallography, mass spectrometry, and CV measure-
ments, respectively.
2H), 7.41 (d, 1H), 7.34 (m, 1H), 7.32–7.31 (m, 1H), 7.26–7.24
7.14 (m, 1H), 3.82 (s, 3H), 2.64–2.63 (m, 4H), 1.64 (m, 4H), 1.33 (m,
(m, 4H),
3026
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Chem. Asian J. 2011, 6, 3020 – 3027