Wong et al.
dry ether was added into a solution containing 2,7-dibrmofluo-
reneone (3.36 g, 10 mmol) in THF (50 mL). The mixture was
refluxed for 8 h, and then quenched with water. The mixture was
extracted with EtOAc and dried over MgSO4. The organic solution
was then concentrated by rotary evaporation. The crude mixture
was dissolved in acetic acid (100 mL), and then concentrated HCl
(4 mL, 12.0 N) was added dropwise. After the solution was heated
for 1 h, the precipitate was collected by filtration to give pure
compound 5b (3.6 g, 74% yield). Mp 319-322 °C; IR (KBr)1739,
silica gel to give pure compound 7a (387 mg, 65% yield). Mp 298-
301 °C; IR (KBr) ν 3058, 2972, 2886, 1613, 1560, 1447, 1407,
1
1268, 1056, 731 cm-1; H NMR (CDCl3, 400 MHz) δ 8.19 (dd,
J ) 7.6, 1.2 Hz, 1H), 8.01-7.97 (m, 3H), 7.91 (dd, J ) 8.0, 3.2
Hz, 1H), 7.84 (dd, J ) 7.6, 4.4 Hz, 1H), 7.75 (dd, J ) 8.0, 3.2 Hz,
1H), 7.54-7.38 (m, 7H), 7.21-7.14 (m, 2H), 6.86 (d, J ) 2.0 Hz,
1H), 6.77-6.72 (m, 2H), 1.34 (s, 9H); 13C NMR (CDCl3, 100 MHz)
δ 155.0 149.5, 148.5, 144.9, 140.7, 140.6, 140.2, 131.1, 129.0,
128.3, 128.2, 128.1, 127.1, 127.0, 126.5, 125.8, 124.1, 124.0, 123.9,
123.1, 122.5, 122.4, 121.6, 121.4, 120.8, 120.7, 120.5, 120.2, 65.7,
35.1, 31.1; MS (m/z, FAB+) 597.3 (50), 595.3 (50), 307.1(100);
HRMS calcd for C37H2781BrN2O 596.1286, found 597.1344, HRMS
calcd for C37H2779BrN2O 594.1307, found 595.1372.
Synthesis of 2,7-Dibromo-2′-(4-tert-butylphenyl-1H-tetrazole-
5-yl)-9,9′-spirobifluorene (7b). Compound 6b (515 mg, 1 mmol)
in thionyl chloride (10 mL) was refluxed for 0.5 h under argon.
After the mixture was cooled to room temperature, the solvent was
removed in a vacuum. The solution of 5-(4-tert-butylphenyl)-1H-
tetrazole (202 mg, 1 mmol) and toluene (5 mL) was added to the
mixture. After the solution was heated for 8 h, the solvent was
removed and the crude product was purified by column chroma-
tography on silica gel (EtOAc/ hexanes ) 1/ 5) to give pure
compound 7b (530 mg, 80%). Mp 369-371 °C; 1H NMR (CDCl3,
400 MHz) δ 8.20 (dd, J ) 8 Hz, 1.6 Hz, 1H), 8.01-7.98 (m, 3H),
7.92 (d, J ) 8 Hz, 1H), 7.72 (d, J ) 8 Hz, 2H), 7.54-7.49 (m,
5H), 7.46 (t, J ) 7.6 Hz, 1H), 7.23 (t, J ) 7.6 Hz, 1H), 6.85 (d,
J ) 1.6 Hz, 2H), 6.77 (d, J ) 7.6 Hz, 1H), 1.58 (s, 9H); 13C NMR
(CDCl3, 100 MHz) δ 164.38, 164.06, 155.17, 149.40, 147.97,
147.79, 144.99, 140.34, 139.77, 131.54, 129.35, 128.67, 127.46,
127.37, 126.87, 126.07, 124.35, 123.54, 122.74, 122.15, 121.80,
121.11, 121.03, 120.97, 66.02, 35.84, 31.89; MS (FAB+, m/z) 674.0
(40); HRMS calcd for C26H1681Br81Br 676.0371, found 677.0430,
HRMS calcd for C26H1679Br81Br 674.0391, found 675.0440, HRMS
calcd for C26H1679Br79Br 672.0412, found 673.0483. Anal. Calcd
for C26H16Br2 : C, 65.89, H, 3.89, N, 4.15. Found: C, 65.90, H,
3.85, N, 4.02.
1
1686, 1447, 1401, 1255, 1162, 1056, 824, 685; H NMR (CDCl3,
400 MHz) δ 7.80 (d, J ) 8.2 Hz, 1H), 7.72 (d, J ) 7.6 Hz, 1H),
7.67 (d, J ) 8.2 Hz, 2H), 7.49 (dd, J ) 8.2, 2.0 Hz, 2H), 7.38 (td,
J ) 7.6, 1.0 Hz, 1H), 7.20 (dd, J ) 7.6, 0.8 Hz, 1H), 7.11 (td, J )
7.6, 0.8 Hz, 1H), 6.85 (d, J ) 2 Hz, 2H), 6.69 (d, J ) 7.6 Hz, 1H),
6.51 (d, J ) 0.8 Hz, 1H), 2.24 (s, 3H); 13C NMR (CDCl3, 100
MHz) δ 150.90, 147.31, 147.03, 141.95, 139.73, 139.18, 138.30,
131.21, 129.33, 128.37, 127.72, 127.55, 124.77, 124.13, 122.04,
121.51, 120.18, 120.11, 65.80, 21.92; MS (FAB+, m/z) 485 (35);
HRMS calcd for C26H1681Br81Br 489.9578, found 489.9604, HRMS
calcd for C26H1679Br81Br 487.9598, found 487.9612, HRMS calcd
for C26H1679Br79Br 485.9619, found 485.9612.
Synthesis of 2-Bromo-2′-carboxyl-9,9′-spirobifluorene (6a).
2-Bromo-2′-methyl-9,9′-spirobifluorene (5a) (1.63 g, 4 mmol) was
dissolved in benzene (15 mL) and acetic acid (15 mL). A solution
of chromium oxide (4.0 g, 40 mmol), acetic acid (5 mL), and water
(10 mL) was added slowly at reflux. After being heated for 8 h,
the mixture was quenched with water and extracted with EtOAc.
The solvent was then removed in a vacuum and the crude product
was purified by recrystallization from CHCl3 and methanol to give
pure compound 6a (1.09 g, 62% yield). Mp 360 °C (DSC); IR (KBr)
ν 3436, 3032, 2355, 2329, 1686, 1619, 1295, 758 cm-1; 1H NMR
(acetone-d6, 400 MHz) δ 8.14-8.11 (m, 3H), 8.04 (d, J ) 7.6 Hz,
1H), 7.99 (d, J ) 8.0 Hz, 1H), 7.61 (dd, J ) 8.0, 1.6 Hz, 1H),
7.51-7.43 (m, 2H), 7.34 (s, 1H), 7.27 (t, J ) 7.6 Hz, 1H), 7.21 (t,
J ) 7.6 Hz, 1H), 6.84 (d, J ) 1.6 Hz, 1H), 6.77 (d, J ) 7.2 Hz,
1H), 6.71 (d, J ) 7.6 Hz, 1H); 13C NMR (DMSO-d6, 100 MHz) δ
166.0, 149.0, 147.4, 147.0, 146.4, 145.0, 140.0, 139.5, 130.7, 129.6,
129.2, 128.8, 128.1, 128.0, 127.9, 127.6, 125.5, 123.4, 123.1, 122.9,
122.2, 121.2, 120.5, 120.4, 120.2, 65.0; MS (m/z, FAB+) 307.0
(30), 154.0 (100); HRMS calcd for C26H1581BrO2 440.0235, found
440.0269, HRMS calcd for C26H1579BrO2 438.0255, found 438.0281.
Synthesis of 2,7-Dibromo-2′-carboxyl-9,9′-spirobifluorene (6b).
2,7-Dibromo-2′-methyl-9,9′-spirobifluorene (5b) (2.3 g, 4.7 mmol)
was dissolved in benzene (35 mL) and acetic acid (30 mL), which
was slowly added to a solution of chromium oxide (2.3 g, 23.5
mmol), acetic acid (5 mL), and water (10 mL) at reflux. After being
heated for 8 h, the mixture was quenched with water, and extracted
with EtOAc. The solvent was removed in a vacuum and the crude
product was purified by recrystallization from CHCl3 and methanol
to give pure compound 6b (1.8 g, 76% yield). Mp 375-377 °C;
Synthesis of D1A1. By the Pd-catalyzed C-N bond formation
reaction, the mixture of compound 7a (595 mg, 1.0 mmol),
diphenylamine (338 mg, 2 mmol), Pd(OAc)2 (0.03 mmol, 6.72 mg),
tri-tert-butyl phosphine (2.4 mL, 0.05 M in toluene), and sodium
tert-butoxide (192 mg, 2 mmol) in dry toluene (5 mL) was refluxed
for 8 h. The mixture then was extracted with CH2Cl2, the organic
layer was washed with water and dried over MgSO4, and the
solvents were evaporated to dryness. Pure D1A1 was isolated by
column chromatography on silica gel (EtOAc/ hexanes ) 1/4) as
a white solid (485 mg, 71% yield). Mp 277 °C (DSC); IR (KBr) ν
2975, 1616, 1595, 1495, 1452, 1293, 1272, 1024, 833, 752, 732,
698 cm-1; 1H NMR (DMSO-d6, 400 MHz) δ 8.19 (d, J ) 7.8 Hz,
1H), 8.15 (d, J ) 8.0 Hz, 1H), 8.05 (d, J ) 7.6 Hz, 1H), 7.97 (t,
J ) 8.9 Hz, 4H), 7.60 (d, J ) 8.3 Hz, 2H), 7.45-7.40 (m, 2H),
7.33 (s, 1H), 7.14-7.07 (m, 5H), 6.99 (d, J ) 8.4 Hz, 1H), 6.92 (t,
J ) 7.3 Hz, 1H), 6.84 (d, J ) 8.0 Hz, 4H), 6.75 (d, J ) 7.5 Hz,
1H), 6.61 (d, J ) 7.5 Hz, 1H), 6.25 (s, 1H), 1.30 (s, 9H); 13C NMR
(CDCl3, 100 MHz) 163.7, 163.5, 154.5, 149.1, 148.2, 148.0, 146.8,
144.5, 140.3, 140.1, 139.7, 130.7, 128.7, 128.6, 127.9, 127.8, 127.7,
126.7, 126.2, 125.4, 123.7, 123.5, 122.8, 122.1, 121.1, 120.5, 120.4,
120.2, 119.9, 117.3, 65.7, 35.2, 31.3; MS (m/z, FAB+) 684 (100),
683 (100), 508 (5), 460 (10), 307 (75), 289 (35); HRMS calcd for
C49H37N3O 683.2937, found 683.2934. Anal. Calcd for C49H37N3-
O: C, 86.06, H, 5.45, N, 6.14. Found: C, 85.98, H, 5.47, N, 6.16.
Synthesis of D2A1. The mixture of compound 7b (1.17 g, 1.7
mmol), diphenylamine (0.88 g, 5.2 mmol), Pd(OAc)2 (7.8 mg, 0.04
mmol), tri-tert-butylphosphine (2.0 mL, 0.05M in toluene), and
sodium tert-butoxide (467 mg, 4.8 mmol) in dry toluene (5 mL)
was refluxed for 8 h. This mixture was extracted with CH2Cl2 and
the organic layer was washed with water and dried over MgSO4.
Pure D1A1 was isolated by column chromatography on silica gel
(EtOAc/ hexanes ) 1/4) (1.22 g, 82% yield). Mp 406 °C (DSC);
1
IR (KBr) ν 3450, 1778, 1707, 1270, 1207, 971 cm-1; H NMR
(DMSO-d6, 400 MHz) δ 8.14 (dd, J ) 11.6, 8 Hz, 2H), 8.06-8.02
(m, 3H), 7.64 (dd, J ) 8.0, 1.8 Hz, 2H), 7.49 (t, J ) 7.6 Hz, 1H),
7.26-7.10 (m, 2H), 6.75-6.72 (m, 3H); MS (EI, m/z) 156(15).
13C NMR (DMSO-d6, 100 MHz) δ 165.8, 148.6, 146.6, 146.0,
144.9, 139.4, 138.8, 130.8, 129.6, 128.8, 128.1, 125.5, 123.2, 123.0,
122.4, 121.2, 120.7, 120.4, 64.7; MS (m/z, FAB+) 517.9 (20), 307.0
(100); HRMS calcd for C25H1481Br81BrO2 519.9320, found 519.9359,
HRMS calcd for C25H1479Br81BrO2 517.9340, found 517.9376,
HRMS calcd for C25H1479Br79BrO2 515.9361, found 515.9362.
Synthesis of 2-Bromo-2′-(4-tert-butylphenyl-1H-tetrazole-5-
yl)-9,9′-spirobifluorene (7a). Compound 6a (518 mg, 1 mmol) in
thionyl chloride (10 mL) was refluxed for 0.5 h under argon. After
being cooled to room temperature, the solvent was removed in a
vacuum. A solution of 5-(4-tert-butylphenyl)-1H-tetrazole [see the
Supporting Information] (202 mg, 1 mmol) and toluene (5 mL)
was added into the mixture. After the solution was heated for 8 h,
the solvent was removed in a vacuum and the crude product was
purified by column chromatography (EtOAc/ hexane ) 1/ 5) on
IR (KBr) ν 2952, 1593, 1493, 1467, 1261, 1016, 751, 698 cm-1
;
464 J. Org. Chem., Vol. 71, No. 2, 2006