The Journal of Organic Chemistry
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mmol) in THF (10 mL) were reacted according to general procedure
A. The reaction mixture was stirred 48 h. The crude product (0.13 g)
was purified (4% H2O aluminum oxide, CH2Cl2, Rf 0.1) to give 9 as a
bright yellow solid (0.06 g, 30%): mp 214−216 °C {lit.27 mp 225−226
°C (benzene-heptane)}; FT-IR (ATR) 2978 (w), 2931 (m), 1732 (s),
1604 (m), 1456 (m), 1348 (m), 1286 (s), 1168 (s), 1128 (s), 1030
(s), 752 (m); HRMS [ASAP, ion trap] (SOLID) [M + H]+ for
C33H43N3O9: calcd. 625.2994, found 625.2989. Anal. Calcd for
C33H42N3O9: C, 63.45; H, 6.78; N, 6.73. Found: C, 63.31; H, 6.85;
N, 6.81. Room temperature CW EPR displays a characteristic three
line nitroxide spectrum: aiso(14N) =1.41(1) mT.
Biradical (13). 4,4′-Biphenol 11 (0.10 g, 0.54 mmol), TPC 5 (0.30
g, 1.63 mmol), DMAP (0.20 g, 1.64 mmol) and EDCI·HCl (0.16 g,
1.03 mmol) in THF (10 mL) were reacted according to general
procedure A. The reaction mixture was stirred 24 h. The crude
product (0.31 g) was purified (4% H2O aluminum oxide, CH2Cl2, Rf
0.2) to give 13 as yellow crystals (0.23 g, 82%). Data are in accordance
with the literature:25 mp 211−213 °C; FT-IR (ATR) 2976 (w), 2931
(w), 1732 (s), 1490 (m), 1346 (m), 1286 (m), 1244 (m), 1194 (s),
1147 (s), 1024 (s), 1001 (s), 792 (s), 759 (s); HRMS [NSI, ion trap]
[M + H]+ calcd for C30H35N2O6 519.2490, found 519.2476. Anal.
Calcd for C30H34N2O6: C, 69.48; H, 6.61; N, 5.40. Found: C, 69.30;
H, 6.75; N, 5.54. Room temperature CW EPR displays a characteristic
three line nitroxide spectrum: aiso(14N) =1.42(1) mT.
Monoradical (17). 4-Hydroxy-4′-iodobiphenyl 16 (0.10 g, 0.34
mmol), TPC 5 (0.12 g, 0.67 mmol), EDCI·HCl (0.10 g, 0.67 mmol),
DMAP (0.08 g, 0.67 mmol) in THF (15 mL) were reacted according
to general procedure A. The reaction mixture was stirred 24 h. The
crude product (0.20 g) was purified (4% H2O aluminum oxide, 3:2
CH2Cl2, ethyl acetate, Rf 0.8) to give 17 as a yellow solid (0.08 g,
72%). Data in accordance with literature:29 mp 157−158 °C; FT-IR
(ATR) 2978 (w), 1730 (s), 1624 (m), 1477 (s), 1458 (m), 1442 (m),
1344 (m), 1282 (m), 1197 (s), 1182 (s), 1165 (s), 1149 (s), 1014
(m), 999 (s), 760(s); MS [ESI, ion trap] [M + H]+ calcd for
C21H22INO3 463.31, found 463.32.
brown solid (0.32 g, 69%): mp 272−274 °C; H NMR (300 MHz,
DMSO-d6) δH 9.67 (s, 2H), 7.81−7.46 (m, 16H), 6.87 (4H, d, J 8.6);
13C{1H} NMR (101 MHz, DMSO-d6) δC 157.7, 140.6, 133.9, 132.0,
131.4, 129.7, 129.4, 127.9, 126.1, 123.1, 119.7, 115.9, 90.3, 88.7;
HRMS [NSI, ion trap] [M − H]− calcd for C34H21O2 461.1547, found
461.1544.
Tris-phenol (23). 4-Hydroxy-4′-iodobiphenyl 16 (0.27 g, 0.91
mmol), PdCl2(PPh3)2 (0.02 g, 0.03 mmol), CuI (0.003 g, 0.02 mmol),
and 1,3,5-triethynylbenzene 19 (0.05 g, 0.3 mmol), 0.5 M aqueous
ammonia solution (15 mL) in THF (15 mL) were reacted according
to general procedure B. The reaction mixture was stirred at room
temperature for 24 h and heated to 60 °C for 2 h. The crude product
(0.26 g) was purified (silica gel, dry-load, 2% MeOH in CH2Cl2, Rf
0.5) to give 23 as a colorless oil, which turned into pale brown flakes
when washed with CH2Cl2 (0.09 g, 60%): mp 134−136 °C; 1H NMR
(300 MHz, DMSO-d6) δH 9.68 (s, 3H), 7.76−7.55 (m, 21H), 6.88
(6H, d, J 8.6); 13C{1H} NMR (101 MHz, DMSO-d6) δC 157.7, 140.7,
133.6, 132.1, 129.7, 127.9, 126.1, 123.9, 119.5, 115.9, 91.1, 87.9;
HRMS [NSI, ion trap] [M − H]− calcd for C48H29O3 654.2122, found
654.2122.
Triradical (24). Tris-phenol 23 (0.05 g, 0.08 mmol), TPC 5 (0.06 g,
0.33 mmol), DMAP (0.03 g, 0.25 mmol), and EDCI·HCl (0.05 g, 0.32
mmol) in THF (10 mL) were reacted according to general procedure
A. The reaction mixture was stirred 48 h. The crude product (0.08 g)
was purified (4% H2O aluminum oxide; 10% EtOAc in CH2Cl2, Rf 0.7)
to give 24 as a yellow solid (0.1 g, 80%): mp 159−160 °C; FT-IR
(ATR) 2974 (w), 2927 (w), 1730 (m), 1490 (m), 1286 (m), 1203(s),
1180(s), 1002 (s), 798 (s); HRMS [NSI, ion trap] [M + NH4]+ calcd
for C75H70N4O9 1170.5137, found 1170.5142. Anal. Calcd for
C75H66N3O9: C, 78.10; H, 5.77; N 3.64. Found: C, 77.86; H, 5.85;
N, 3.54. Room temperature CW EPR displays a characteristic three
line nitroxide spectrum: aiso(14N) = 1.42(1) mT.
1,3,5,7-Tetraphenyladamantane (26). 1-Bromo adamantane 25
(6.00 g, 27.89 mmol) was reacted following the procedure described
by Reichert et al.38 in the presence of tert-butyl bromide (9.5 mL,
84.59 mmol) and AlCl3 (0.37 g, 2.77 mmol) to give 26 as a white solid
after chloroform Soxhlet extraction (11.50 g, 90%): mp > 300 °C; FT-
IR (ATR) 3020 (m), 1597 (m), 1494 (m), 1442 (m), 1355 (m), 1078
(m), 1031 (m), 750 (s); 13C CP/MAS NMR (14.1 T) δC (ppm) 39.2,
45.1, 51.3, 124.7, 127.2, 129.1, 130.2, 149.8.
1,3,5,7-Tetrakis(4-iodophenyl)adamantane (28). Following the
procedure described by Drew et al.,42 26 (2.00 g, 4.54 mmol) was
reacted with iodine (4.60 g, 9.06 mmol) and [bis(trifluoroaceteoxy)-
iodo]benzene 27 (4.00 g, 9.30 mmol). The crude product (4.80 g) was
purified via silica column chromatography (5:1 hexane in CH2Cl2, Rf
0.13) to give 28 as a white solid (2.20 g, 51%) with data in accordance
with the literature:31 mp 236−238 °C {lit.42 250 °C (CHCl3,
MeOH)}; FT-IR (ATR) 2920 (w), 2897 (w), 2850 (w), 1483 (s),
1446 (w), 1388 (m), 1355 (m), 1211 (w), 1176 (w), 1064 (m), 1002
(s), 887 (w), 821 (s), 775 (s); 1H NMR (400 MHz, methylene
chloroform-d) δ 7.72−7.61 (m, 8H), 7.23−7.14 (m, 8H), 2.06 (s,
12H); HRMS [ASAP, ion trap] (SOLID) [M]+ calcd for C34H28I4
943.8364, found 943.8366.
1,3,5,7-Tetrakis(4-ethynlphenyl)adamantane (20). Following the
procedure described by Lu et al.,34 28 (1.20 g, 1.27 mmol),
trimethylsilylacetylene (2.7 g, 27.49 mmol), PdCl2(PPh3)2 (0.062 g,
0.09 mmol) and CuI (0.37 g, 1.92 mmol) in toluene (25 mL) and
triethylamine (11 mL). The crude product (2.30 g) was suspended in
anhydrous MeOH (38 mL) together with K2CO3 (4.20 g, 30.39
mmol). The reaction was sirred for 24 h. The crude product (0.50 g)
was purified via silica column chromatography (10% CH2Cl2 in
hexane, Rf 0.28) to give 20 as a white solid (0.7 g, 67%). Data are in
accordance with the literature:34 mp 178−180 °C; FT-IR (ATR) 3284
(s), 2924 (m), 2899 (m), 2850 (m), 2106 (w), 1606 (w), 1504 (s),
1446 (w), 1402 (w), 1357 (m), 1259 (w), 1112 (w), 1016 (m), 893
1
(w), 830 (s), 790 (s); H NMR (400 MHz, Chloroform-d) δ 7.52−
7.46 (m, 8H), 7.45−7.38 (m, 8H), 3.06 (s, 4H), 2.12 (s, 12H); HRMS
[ASAP, ion trap] (SOLID) [M + H]+ calcd for C42H33 537.2577,
found 537.2572.
Biradical (21). Bis-phenol 22 (0.09 g, 0.19 mmol), TPC 5 (0.09 g,
0.5 mmol), DMAP (0.06 g, 0.49 mmol), and EDCI·HCl (0.08 g, 0.52
mmol) in THF (15 mL) were reacted according to general procedure
A. The mixture was left stirring for 40 h. The crude product (0.25 g)
was purified (4% H2O aluminum oxide; CH2Cl2, Rf 0.4) to give 21 as a
pale yellow solid (0.07 g, 45%): mp 212−214 °C; FT-IR (ATR) 2933
(w), 2868 (w), 1730 (s), 1490 (m), 1346 (m), 1286 (m), 1185−1149
(s), 999 (s), 800 (s); HRMS [ESI, ion trap] [M + NH4]+ calcd for
C52H50N3O6 812.3694, found 812.3697. Anal. Calcd for C52H46N2O6:
C, 78.57; H, 5.83; N, 3.52. Found: C, 78.47; H, 5.84; N, 3.42. Room
temperature CW EPR displays a characteristic three line nitroxide
spectrum: aiso(14N) = 1.42(1) mT.
Bis-phenol (22). 4-Hydroxy-4′-iodobiphenyl 16 (0.30 g, 1.01
mmol), PdCl2(PPh3)2 (0.01 g, 0.02 mmol), CuI (0.005 g, 0.02
mmol), and 1,3-diethynylbenzene 18 (0.09 mL, 0.61 mmol), 0.5 M
aqueous ammonia solution (5 mL) in THF (5 mL) were reacted
according to general procedure B. The mixture was stirred for 24 h
before being heated to 60 °C for 2 h. The crude product (0.48 g) was
purified (silica gel, 10% EtOAc in CH2Cl2, Rf 0.5) to give 22 as a pale
Tetrakis-phenol (29). Compound 28 (0.5 g, 0.53 mmol),
PdCl2(PPh3)2 (0.02 g, 0.03 mmol), and CuI (0.002 g, 0.01 mmol)
were dissolved THF (10 mL). 4′-Ethynyl-[1,1′-biphenyl]-4-ol 30
(0.53 g, 2.72 mmol) was dissolved THF (5 mL) in a separate flask.
The two flasks were degassed using freeze−pump−thaw cycles (×3).
The alkyne solution was added dropwise to the first flask. The
obtained mixture was degassed once more before dropwise addition of
10 mL of a 0.5 M aqueous ammonia solution. The reaction mixture
was heated to 60 °C under nitrogen atmosphere for 40 h before being
heated under reflux for 30 min. The two phases were separated, and
the aqueous layer was extracted with EtOAc. The organic layer was
dried over MgSO4, and solvents were removed. The obtained solids
(3.5 g) were triturated with toluene and filtered to give 29 as a brown
solid (0.65 g, 60%): mp > 300 °C; FT-IR (ATR) 2927 (w), 1734 (m),
1718 (m), 1604 (w), 1506 (m), 1490 (m), 1438 (w), 1348 (m), 1286
1
(m), 1238 (m), 1990 (s), 1002 (s), 810 (s), 800 (s); H NMR (400
MHz, DMSO-d6) δH 9.66 (s, 4H), 7.64−7.54 (m, 40H), 6.86 (d, J 8.2,
I
dx.doi.org/10.1021/jo5015678 | J. Org. Chem. XXXX, XXX, XXX−XXX