10358 Macromolecules, Vol. 43, No. 24, 2010
Huang and Huang
resulted Grignard reagents were reacted with 4 to afford 10 and 14,
respectively, in fair yields. Cyclizations of 10 and 14 with 35%
hydrogen chloride in acetic acid solution provided 11 and 15,
respectively, in good to excellent yields. Grignard reaction product
of 4-bromoanisole was reacted with trimethyl borate in dry THF
gave 17 in good yields. Couple reactions of compounds 11 and 15
were carried out using Suzuki reaction with 2.3 equiv of com-
pounds 17 in solvent mixture of toluene, sodium carbonate aque-
ous solution (1 M) and tetrakis(triphenyl phosphine) palladium (0)
furnished compounds 18 and 19 in good to excellent yields.
Deprotection of compounds 18 and 19 with BBr3 in dry dichlor-
omethane gave monomers MOHa and MOHb. The detailed
procedure for each precursor is given separately below.
2-Aminobiphenyl (1). To a high pressure reactor containing
2-nitrobiphenyl (25.0 g, 125 mmol), 5% Pd/C (0.3 g) and ethyl
acetate (80 mL) was slowly introduced hydrogen gas until 5 atm.
The reaction mixture was maintained at 5 atm and stirred at
room temperature for 24 h. The resultant solution was filtered to
remove solid contents. Then the solvent was removed under
reduced pressure and the resultant was purified by column
chromatography using hexane as eluent, which gives compound 1
as a light brown liquid (16.9 g, 80%); Rf (EAC:hexane =1: 20) =
0.2. MS (m/z): 169.1. Anal. Calcd for C12H11N: C, 85.17; H, 6.55;
N, 8.28. Found: C, 85.08; H, 6.47; N, 8.20.
2-Iodobiphenyl (2). An aqueous sodium nitrite solution (2.1
M, 77.0 mL) was added dropwise into a reaction mixture
containing compound 1 (23.0 g, 136 mmol) and 35% hydro-
chloric acid (70.0 mL), and the resulting mixture was stirred at
0 °C for 15 min. The above mixture was poured into a solution
containing potassium iodide (83.4 g, 502 mmol) and water (280
mL) and the combined reaction solution was stirred at room tem-
perature overnight. The mixture was extracted with ethyl acetate
(3 ꢀ 100 mL). The combined organic layers were washed with H2O
(3 ꢀ 100 mL) and dried over MgSO4. Then the solvent was
removed under reduced pressure and the resultant was purified
by column chromatography using hexane as eluent, which gives
compound 2 as a light red liquid (28.5 g, 75%); Rf (EAC:hexane =
1:20) = 0.7. MS (m/z): 280.0. Anal. Calcd for C12H9I: C, 51.46; H,
3.24; I, 45.31. Found: C, 51.42; H, 3.19; I, 45.25.
2,7-Dibromofluorene (3). A reaction mixture containing fluor-
ene (12.5 g, 75 mmol), N-Bromosuccinimide (27.4 g, 153 mmol)
and propylene carbonate (90 mL) was stirred at reflux for 3 h.
The mixture was poured into methanol. After filtration and
recrystallization from ethanol, the compound 3 was obtained as
a white solid (18.2 g, 75%); Rf (hexane) = 0.8. MS (m/z): 323.7.
Anal. Calcd for C13H8Br2: C, 48.19; H, 2.49; Br, 49.32. Found:
C, 48.09; H, 2.41; Br, 49.25.
mixture containing compound 5 (21.6 g, 116 mmol) and 35%
hydrochloric acid (60.0 mL) and the resulted mixture was stirred
at 0 °C for 15 min. The above mixture was poured into a solution
containing potassium iodide (71.5 g, 400 mmol) and water
(240 mL) and the combined reaction solution was stirred at
room temperature overnight. The mixture was extracted with
ethyl acetate (3 ꢀ 100 mL). The combined organic layers were
washed with H2O (3 ꢀ 100 mL) and dried over MgSO4. Then the
solvent was removed under reduced pressure and the resultant
was purified by column chromatography using hexane as eluent,
which gives compound 6 as a light red liquid (24.0 g, 70%); Rf
(EAC:hexane = 1:10) = 0.8. MS (m/z): 295.8. Anal. Calcd for
C12H9IO: C, 48.67; H, 3.06; I, 42.86; O, 5.40. Found: C, 48.58;
H, 3.02; I, 42.82; O, 5.48.
9-(2-Biphenyl)-2,7-dibromo-9-fluorenol (10). To a solution of
magnesium (0.32 g, 13 mmol), iodine (0.05 g), and 5 mL of
anhydrous THF was slowly added compound 2 (2.5 g, 9 mmol)
in 25 mL of anhydrous THF via dropping funnel under nitrogen
atmosphere. During the addition period, the reaction mixture
was stirred at reflux for 2 h.
To a solution of compound 4 (2.3 g, 7 mmol) in anhydrous
THF (30 mL) was slowly added the above Grignard reagent at
room temperature under nitrogen atmosphere. After complete
addition, the reaction mixture was stirred at reflux for 12 h. The
mixture was poured into an HCl aqueous solution (3M, 200 mL)
and extracted with diethyl ether (3 ꢀ 100 mL). The combined
organic layers were washed with H2O (3 ꢀ 100 mL) and dried
over MgSO4. Then the solvent was removed under reduced
pressure and the resultant was purified by column chromatog-
raphy using hexane as eluent. The pure product was obtained as
a light yellow solid (2.2 g, 63%); Rf (EAC:hexane = 1:10) = 0.4;
MS (m/z): 491.8. Anal. Calcd for C25H16Br2O: C, 61.00; H, 3.28;
Br, 32.47; O, 3.25. Found: C, 60.91; H, 3.23; Br, 32.42; O, 3.28.
Spiro-9-(2,7-dibromofluorene)-90-fluorene (11). A reaction
mixture containing compound 10 (6.3 g, 13 mmol), 35% hydro-
chloric acid (0.3 mL) and acetic acid (60 mL) was stirred at 140
°C for 2.5 h. The mixture was poured into methanol. After
filtration and washing with water twice, the compound 11 was
obtained as a brown solid (5.5 g, 89%); Rf (EAC:hexane = 1:10) =
0.8; MS (m/z): 473.9; Anal. Calcd for C25H14Br2: C, 63.32; H, 2.98;
Br, 33.70. Found: C, 63.26; H, 2.95; Br, 33.66.
2,7-Dibromo-9-(2-phenoxyphenyl)-9-fluorenol (14). To a solu-
tion of magnesium (0.85 g, 35 mmol), iodine (0.05 g) and 10 mL
of anhydrous THF was slowly added compound 6 (7.0 g,
23 mmol) in 60 mL of anhydrous THF via dropping funnel
under nitrogen atmosphere. During the addition period, the
reaction mixture was stirred at reflux for 2 h.
2,7-Dibromo-9-fluorenone (4). To a reaction mixture contain-
ing compound 3 (15.0 g, 46 mmol) and acetic acid (190 mL) was
added CrO3 (20.0 g, 200 mmol) in 10 portions. The above
reaction solution was stirred at 120 °C for 1 h. The mixture
was poured into methanol. After filtration and washing with
water twice, the compound 4 was obtained as a yellow solid (10.9 g,
70%); Rf (EAC:hexane = 1:10) = 0.5. MS (m/z): 337.7. Anal.
Calcd for C13H6Br2O: C, 46.20; H, 1.79; Br, 47.28; O, 4.73. Found:
C, 46.14; H, 1.71; Br, 47.08; O, 4.71.
2-Aminophenyl Phenyl Ether (5). To a high pressure reactor
containing 2-nitrophenyl phenyl ether (25.0 g, 116 mmol), 5%
Pd/C (0.28 g) and ethyl acetate (74 mL) was slowly introduced
hydrogen gas until 5 atm. The reaction mixture was maintained
at 5 atm and stirred at room temperature for 20 h. The resultant
solution was filtered to remove solid contents. Then the solvent
was removed under reduced pressure and the resultant was
purified by column chromatography using EAC:hexane =
1:20 as eluent, which gives compound 5 as a light brown liquid
(16.9 g, 85%); Rf (EAC:hexane = 1:5) = 0.4. MS (m/z): 185.0.
Anal. Calcd for C12H11NO: C, 77.81; H, 5.99; N, 7.56; O, 8.64.
Found: C, 77.83; H, 5.92; N, 7.52; O, 8.67.
To a solution of compound 4 (4.8 g, 14 mmol) in anhydrous
THF (30 mL) was slowly added the above Grignard reagent at
room temperature under nitrogen atmosphere. After complete
addition, the reaction mixture was stirred at reflux for 20 h. The
mixture was poured into an HCl aqueous solution (3M, 200 mL)
and extracted with diethyl ether (3 ꢀ 100 mL). The combined
organic layers were washed with H2O (3 ꢀ 100 mL) and dried over
MgSO4. Then the solvent was removed under reduced pressure
and the resultant was purified by column chromatography using
hexane as eluent. The pure product was obtained as a light yellow
solid (4.6 g, 65%); Rf (EAC:hexane = 1:10) = 0.5; MS (m/z):
507.9. Anal. Calcd for C25H16Br2O2: C, 59.08; H, 3.17; Br, 31.45;
O, 6.30. Found: C, 58.88; H, 3.14; Br, 31.37; O, 6.35.
Spiro-9-(2,7-dibromofluorene)-90-xanthene (15). A reaction
mixture containing compound 14 (9.0 g, 18 mmol), 35% hydro-
chloric acid (0.8 mL) and acetic acid (80 mL) was stirred at
140 °C for 2 h. The mixture was poured into methanol. After
filtration and washing with water twice, the compound 15 was
obtained as a gray solid (5.6 g, 64%). Melting temperature:
273-275 °C. Rf (EAC:hexane = 1:10) = 0.7. MS (m/z): 440.3.
Anal. Calcd for C25H14Br2O: C, 61.26; H, 2.88; Br, 32.60; O,
1
2-Iodophenyl Phenyl Ether (6). An aqueous sodium nitrite
solution (2.1 M, 66.0 mL) was added dropwise into a reaction
3.26. Found: C, 61.15; H, 2.82; Br, 32.51; O, 3.24. H NMR
(CDCl3): δ (ppm) = 6.38-6.40 (m, 2H), 6.81-6.84 (m, 2H),