Macromolecules, Vol. 35, No. 13, 2002
Poly(p-phenylenevinylenes) 4999
3.79 (s, 3H), 6.68 (s, 1H), 7.26 (s, 1H). HRMS: Calcd for
C9H1179BrO: 213.999. Found: 213.994.
with toluene). The solvent was evaporated to yield 1.30 g (97%)
of 2-(2′,5′-bis(octyloxy)benzene)terephthalic acid diethyl ester
1
2-Br om o-5-m eth oxyter ep h th a lic Acid (3). KMnO4 (13.0
g, 82 mmol) was added to 2 (8.0 g, 37.2 mmol) in water (125
mL) under stirring. After 1.5 h at reflux, another portion of
KMnO4 (13.0 g) was added, and the solution was refluxed for
16 h. Precipitated MnO2 was filtered off. The desired product
was precipitated by the addition of 2 M HCl to the filtrate.
Filtration and drying afforded 3.8 g (37%) of 2-bromo-5-
methoxyterephthalic acid as a colorless solid; mp 265 °C (dec).
1H NMR (400 MHz, CD3OD): δ (ppm) 3.92 (s, 3H), 7.48 (s,
1H), 7.99 (s, 1H). HRMS: Calcd for C9H779BrO5: 273.948.
Found: 273.935.
as an oil. H NMR (400 MHz, CDCl3): δ (ppm) 0.84-0.92 (m,
6H), 1.06 (t, 3H), 1.14-1.57 (m, 22H), 1.40 (t, 3H), 1.71-1.79
(m, 2H), 3.71-3.78 (m, 2H), 3.94 (t, 2H), 4.11 (q, 2H), 4.39 (q,
2H), 6.79-6.88 (m, 3H), 7.92 (d, 1H), 8.00 (s, 1H), 8.04 (d, 1H).
FABHRMS (NBA/Cs): Calcd for C34H50O6: 554.361. Found:
554.351.
2-(2′,5′-Bis(octyloxy)ben zen e)-1,4-bis(h yd r oxym eth yl)-
ben zen e (9a ). To a stirred solution of 8a (1.21 g, 2.18 mmol)
in absolute THF (20 mL) was added LiAlH4 (0.5 g, 13.2 mmol)
in portions. The solution was refluxed for 1 h before it was
treated with water. The THF was evaporated, and diethyl
ether and water were added. The two phases were separated,
and the water phase was extracted twice with diethyl ether.
The resulting organic phases were combined and washed with
water. The organic extracts were dried over Na2SO4, evapo-
rated, and purified with column chromatography (silica gel,
the byproducts were eluted with dichloromethane and the
product was eluted with ethyl acetate) to yield 0.98 g (96%) of
2-(2′,5′-bis(octyloxy)benzene)-1,4-bis(hydroxymethyl)benzene
2-Br om o-5-m et h oxyt er ep h t h a lic Acid Diet h yl E st er
(4). A stirred solution of 3 (1.6 g, 5.8 mmol) in ethanol (50
mL) and sulfuric acid (1 mL) was refluxed for 4 h. Excess
ethanol was evaporated, and diethyl ether and Na2CO3 (10%)
were added. The two phases were separated, and the organic
phase was washed twice with Na2CO3 (10%) and water. Drying
over Na2SO4 and evaporation yielded 1.29 g (67%) of 2-bromo-
5-methoxyterephthalic acid diethyl ester as a solid; mp 55-
1
1
57 °C. H NMR (400 MHz, CDCl3): δ (ppm) 1.38 (t, 3H), 1.42
as a colorless oil. H NMR (400 MHz, CDCl3): δ (ppm) 0.83-
(t, 3H), 3.92 (s, 3H), 4.37 (q, 2H), 4.43 (q, 2H), 7.34 (s, 1H),
8.00 (s, 1H). FABHRMS (NBA/Cs): Calcd for (M+H)+
C13H1479BrO5: 331.018. Found: 330.978.
0.90 (m, 6H), 1.10-1.54 (m, 21H), 1.72-1.80 (m, 3H), 3.69 (m,
1H), 3.89 (m, 1H), 3.90 (t, 2H), 4.39 (dd, 2H), 4.72 (s, 2H), 6.73
(d, 1H), 6.86 (dd, 1H), 6.92 (d, 1H), 7.21 (s, 1H), 7.39 (d, 1H),
2-Br om o-1,4-bis(octyloxy)ben zen e (5). A solution of NBS
(4.26 g, 23.7 mmol) in 50 mL of DMF was added dropwise to
1,4-bis(octyloxy)benzene (8.0 g, 23.9 mmol) dissolved in 75 mL
of DMF. The solution was stirred at room temperature for 2
h, and Na2S2O5 (10%), 2 M HCl, and pentane were added. The
two phases were separated, and the water phase was extracted
with pentane. The resulting organic phases were combined and
washed with 2 M HCl and water. The organic extracts were
dried over Na2SO4, evaporated, and purified with column
chromatography (silica gel, pentane/dichloromethane (10/1) as
eluent) to yield 5.8 g (59%) of 2-bromo-1,4-bis(octyloxy)benzene
7.52 (d, 1H). FABHRMS (NBA/Cs): Calcd for
470.340. Found: 470.314.
C30H46O4:
2-(2′,5′-Bis(oct yloxy)b en zen e)-1,4-b is(b r om om et h yl)-
ben zen e (10a ). To a solution of 9a (0.90 g, 1.93 mmol) in
absolute ether (15 mL) was added PBr3 (0.80 g, 2.96 mmol).
The solution was stirred at room temperature for 3 h, and
Na2S2O5 (10%) was added. The two phases were separated,
and the water phase was extracted with diethyl ether. The
organic phases were combined and washed with water. The
organic extracts were dried over Na2SO4, evaporated, and
purified with column chromatography (silica gel, dichlo-
romethane as eluent) to yield 0.60 g (50%) of 2-(2′,5′-bis-
(octyloxy)benzene)-1,4-bis(bromomethyl)benzene as colorless
1
as a colorless oil. H NMR (400 MHz, CDCl3): δ (ppm) 0.85-
0.92 (m, 6H), 1.23-1.58 (m, 20H), 1.70-1.84 (m, 4H), 3.88 (t,
2H), 3.95 (t, 2H), 6.78 (dd, 1H), 6.82 (d, 1H), 7.11 (d, 1H).
HRMS: Calcd for C22H3779BrO2: 412.198. Found: 412.214.
1,4-Bis(octyloxy)ben zen e-2-bor on ic Acid (6). To a stirred
solution of 5 (4.6 g, 11.1 mmol) in absolute diethyl ether (40
mL) under nitrogen was added n-BuLi (7.0 mL, 1.6 M in
hexane, 11.2 mmol) at -78 °C. The solution was allowed to
warm to room temperature for 30 min. The reaction mixture
was then cooled to -78 °C, and tributyl borate (5.0 mL, 18.5
mmol) was added. The solution was allowed to warm to room
temperature for 2 h before the reaction was quenched with
the addition of 1 M HCl. The two phases were separated, and
the water phase was extracted with two portions of diethyl
ether. The combined organic extracts were washed successively
with three portions of 1 M NaOH and water, dried over Na2-
SO4, and evaporated. The resulting colorless oil, which solidi-
fied upon standing, of crude 1,4-bis(octyloxy)benzene-2-boronic
acid (4.0 g) was used without further purification.
crystals; mp 63.5-64.5 °C. 1H NMR (400 MHz, CDCl3):
δ
(ppm) 0.84-0.91 (m, 6H), 1.12-56 (m, 22 H), 1.72-1.80 (m,
2H), 3.76-3.84 (m, 2H), 3.94 (t, 2H), 4.39 (dd, 2H), 4.48 (s,
2H), 6.86 (d, 1H), 6.89 (s, 1H), 6.89 (d, 1H), 7.24 (d, 1H), 7.37
(dd, 1H), 7.50 (d, 1H). FABHRMS (NBA/Cs): Calcd for
C
30H4479Br2O2: 594.171. Found: 594.194.
2-(2′,5′-Bis(oct yloxy)b en zen e)-5-m et h oxyt er ep h t h a l-
ic Acid Dieth yl Ester (8b). To a stirred solution of 4 (0.70 g,
2.11 mmol) and Pd(PPh3)4 (100 mg, 86.5 µmol) under nitrogen
in toluene (20 mL) was added excess 6 (1.0 g crude) and 1 M
NaHCO3 (15 mL). The reaction mixture was refluxed over-
night. The two phases were separated, and the water phase
was extracted with toluene. The catalyst was removed by
filtering the organic solution through a short column of silica
gel (product eluted with diethyl ether). The solvent was
evaporated to yield 1.11 g (90%) of 2-(2′,5′-bis(octyloxy)-
benzene)-5-methoxyterephthalic acid diethyl ester as an oil.
1H NMR (400 MHz, CDCl3): δ (ppm) 0.84-0.92 (m, 6H), 1.01
(t, 3H), 1.16-1.58 (m, 22H), 1.73-1.81 (m, 2H), 1.37 (t, 3H),
3.71-3.77 (m, 2H), 3.91-3.96 (m, 2H), 3.99 (s, 3H), 4.09 (q,
2H), 4.36 (q, 2H), 6.75-6.85 (m, 3H), 7.48 (s, 1H), 7.74 (s, 1H).
FABHRMS (NBA/Cs): Calcd for C35H52O7: 584.371. Found:
584.387.
2-(2′,5′-Bis(oct yloxy)b en zen e)-5-m et h oxy-1,4-b is(h y-
d r oxym eth yl)ben zen e (9b). To a stirred solution of 8b (0.80
g, 1.37 mmol) in absolute THF (30 mL) was added LiAlH4 (0.15
g, 3.95 mmol) in portions. The solution was kept at room
temperature for 1 h before it was treated with water. The THF
was evaporated, and diethyl ether and water were added. The
two phases were separated, and the water phase was extracted
twice with diethyl ether. The resulting organic phases were
combined and washed with water. The organic extracts were
dried over Na2SO4, evaporated, and purified with column
chromatography (silica gel, the byproducts were eluted with
dichloromethane/diethyl ether (10/1) and the product was
eluted with diethyl ether) to yield 0.55 g (80%) of 2-(2′,5′-bis-
(octyloxy)benzene)-5-methoxy-1,4-bis(hydroxymethyl)ben-
2-Br om oter ep h th a lic Acid Dieth yl Ester (7). A stirred
solution of 2-bromoterephthalic acid (10.0 g, 40.7 mmol) in
ethanol (100 mL) and sulfuric acid (2 mL) was refluxed for 4
h. Excess ethanol was evaporated, and diethyl ether and Na2-
CO3 (10%) were added. The two phases were separated, and
the organic phase was washed twice with Na2CO3 (10%) and
water. Drying over Na2SO4 and evaporation yielded 8.0 g (67%)
of 2-bromoterephthalic acid diethyl ester as a colorless oil. 1H
NMR (400 MHz, CDCl3): δ (ppm) 1.38-1.45 (m, 6H), 4.37-
4.46 (m, 4H), 7.79 (d, 1H), 8.01 (d, 1H), 8.31 (s, 1H). FABHRMS
(NBA/Cs): Calcd for (M+H)+ C12H1479BrO4: 301.008. Found:
300.975.
2-(2′,5′-Bis(octyloxy)ben zen e)ter ep h th a lic Acid Dieth -
yl Ester (8a ). To a stirred solution of 7 (0.725 g, 2.41 mmol)
and Pd(PPh3)4 (100 mg, 86.5 µmol) under nitrogen in toluene
(15 mL) was added excess 6 (2.0 g crude) and 1 M NaHCO3
(10 mL). The reaction mixture was refluxed overnight. The
two phases were separated, and the water phase was extracted
with toluene. The catalyst was removed by filtering the organic
solution through a short column of silica gel (product eluted