Vougioukalakis et al.
JOCArticle
solution of the appropriate Grignard reagent (MeMgI, EtMgI,
or PhMgBr, 30 mmol), in dry Et2O (100 mL), at 0 °C. The
reaction was stirred overnight at room temperature and then
cooled at 0 °C before being quenched with 3 mL of 1 N aqueous
NaOH solution. After being washed with brine, the organic
phase was dried over anhydrous MgSO4 and concentrated
(rotary evaporator) to afford the desired alcohol as a yellow
solid (88-92% yield). All substituted fluorenols were sub-
sequently used without any further purification.
147.87, 147.18, 147.09, 146.84, 146.30, 145.67, 145.51, 144.82,
144.58, 143.69, 143.59, 143.35, 142.69, 142.39, 141.70, 141.50,
139.74, 138.03, 135.18, 129.46, 128.64, 127.74, 126.44, 125.17,
121.04, 85.38, 58.44.
9-Azafullerenyl-9-methylfluorene (8b): mp>360 °C; IR (KBr):
v (cm-1) 2920, 1510, 1441, 1422, 1185, 1083, 983, 761, 740, 672,
577, 524, 483; UV-vis (CS2) λmax (nm) 379, 450, 593, 730, 816;
1
MS (FAB) m/z 902 (Mþ), 722 (C59Nþ); H NMR (500 MHz,
CS2-CDCl3) δ 8.30 (d, J = 7.5 Hz, 2H), 7.96 (d, J = 7.5 Hz,
2H), 7.60 (m, 2H), 7.53 (m, 2H), 2.95 (s, 3H); 13C NMR (125
MHz, CS2-CDCl3) δ 156.62, 148.89, 148.32, 148.07, 147.94,
147.93, 147.72, 147.12, 147.03, 146.99, 146.80, 146.45, 146.25,
145.62, 145.48, 144.82, 144.76, 143.69, 143.34, 142.68, 142.41,
141.89, 141.49, 141.34, 139.34, 137.90, 135.23, 129.41, 127.86,
127.23, 125.22, 121.04, 88.91, 59.80, 20.05.
9-Azafullerenyl-9-ethylfluorene (8c): mp>360 °C; IR (KBr):
v (cm-1) 2917, 1510, 1443, 1423, 1185, 1088, 1007, 965, 841, 761,
742, 679, 577, 523, 483; UV-vis (CS2) λmax (nm) 384, 451, 596,
731, 817; MS (FAB) m/z 916 (Mþ), 722 (C59Nþ); 1H NMR (500
MHz, CS2-CDCl3) δ 8.24 (d, J = 7.5 Hz, 2H), 7.96 (d, J = 7.6
Hz, 2H), 7.61 (m, 2H), 7.54 (m, 2H), 3.89 (q, J = 6.9 Hz, 2H),
0.91 (t, J = 7.2 Hz, 3H); 13C NMR (125 MHz, CS2-CDCl3) δ
156.59, 148.17, 147.90, 147.70, 147.12, 146.46, 146.24, 145.63,
145.50, 144.78, 144.76, 144.53, 143.54, 142.44, 141.89, 141.51,
141.40, 141.34, 137.86, 129.38, 127.82, 127.30, 121.11, 89.04,
65.27, 26.02, 9.32.
9-Azafullerenyl-9-phenylfluorene (8d): mp >360 °C; IR (KBr)
v (cm-1) 2915, 1490, 1449, 1421, 1186, 1091, 1080, 903, 845, 737,
696, 581, 524, 482; UV-vis (CS2): λmax (nm) 384, 450, 595, 728,
813; MS (FAB) m/z 964 (Mþ), 722 (C59Nþ); 1H NMR (500
MHz, CS2-CDCl3) δ 8.68 (d, J = 7.6 Hz, 2H), 8.62 (d, J = 7.5
Hz, 2H), 7.98 (d, J = 7.7 Hz, 2H), 7.58 (m, 7H); 13C NMR (125
MHz, CS2-CDCl3) δ 156.71, 147.66, 147.53, 147.03, 147.01,
146.75, 146.46, 146.45, 146.24, 145.48, 144.81, 144.47, 143.70,
143.36, 142.86, 142.73, 142.50, 141.83, 141.54, 141.34, 138.92,
137.65, 130.56, 129.94, 129.57, 129.25, 128.57, 127.83, 121.04,
30.53.
9-Azafullerenyldihydroanthracene (10a). 9,10-Dihydroanthra-
cene (748 mg, 4.15 mmol) was added to a degassed (5 vacuum/
argon cycles) solution of 1 (20 mg, 13.8 ꢀ 10-3 mmol) in HPLC
grade ODCB (40 mL). The mixture was heated at 160 °C for 4 h
under argon and the reaction was monitored by HPLC at 326 nm.
After distillation of ODCB at 55 °C under reduced pressure, the
crude mixture was washed and centrifuged 6 times with acetonitrile
in order to remove the remained tetrahydroanthracene. Chromato-
graphic purification, using hexane as eluent (the crude reaction
mixture was loaded with CS2), afforded 10a as a black solid (3.7
mg, 30% yield). mp >360 °C; IR (KBr) v (cm-1) 2914, 1510, 1449,
1419, 1184, 1091, 1004, 953, 881, 744, 725, 649, 577, 523, 484, 448;
UV-vis (CS2) λmax (nm) 386, 452, 599, 739, 827; HRMS (ESI)
calcd for C73H11N 901.0897, found 901.0902; MS (FAB) m/z 902
(Mþ), 722 (C59Nþ); 1H NMR (500 MHz, CS2-CDCl3) δ 8.06 (m,
2H), 7.57 (m, 2H), 7.51 (m, 4H), 6.13 (s, 1H), 4.59 (d, J = 20 Hz,
1H), 4.28 (d, J = 20 Hz, 1H); 13C NMR (125 MHz, CS2-CDCl3)
δ 155.83, 149.24, 148.41, 148.22, 148.12, 147.89, 147.80, 147.20,
147.02, 146.81, 146.46, 146.25, 145.64, 145.51, 144.90, 144.82,
144.59, 143.64, 143.30, 142.63, 142.32, 141.93, 141.60, 141.39,
141.37, 139.74, 138.71, 138.09, 134.94, 133.51, 132.21, 129.17,
128.62, 126.91, 125.00, 58.92, 37.35.
9-Methyl-9-fluorenol: 1H NMR (500 MHz, CDCl3) δ 7.65 (d,
J = 7.5 Hz, 2H), 7.59 (d, J = 7.5 Hz, 2H), 7.40 (m, 2H), 7.35 (m,
2H), 2.06 (s, 1H), 1.77 (s, 3H).
1
9-Ethyl-9-fluorenol: H NMR (500 MHz, CDCl3) δ 7.64 (d,
J = 7.5 Hz, 2H), 7.53 (d, J = 7.5 Hz, 2H), 7.34 (m, 2H), 7.33 (m,
2H), 2.22 (q, J = 7.5 Hz, 2H), 2.00 (s, 1H), 0.58 (t, J = 7.0 Hz,
3H).
9-Phenyl-9-fluorenol: 1H NMR (500 MHz, CDCl3) δ 7.71 (d,
J = 8.0 Hz, 2H), 7.39 (m, 6H), 7.28 (m, 5H), 2.50 (s, 1H).
2. Substituted Fluorenes 7b-d. Each substituted fluorenol
(23 mmol) was dissolved in dry CH2Cl2 (40 mL), together with
triethylsilane (5.37 g, 46 mmol). After the reaction mixture was
cooled at 0 °C, etherated boron trifluoride was added at one time
(6.56 g, 46 mmol). The reaction mixture was kept at 0 °C for 1 h
and quenched with the addition of aqueous saturated Na2CO3
(10 mL). Following the addition of Et2O (120 mL), the organic
layer was washed with brine, dried over MgSO4, and purified
by column chromatography (hexanes) to afford the desired
9-substituted fluorene in high yields (70-85%).
1
9-Methyl-9H-fluorene (7b): H NMR (500 MHz, CDCl3) δ
7.80 (d, J = 7.5 Hz, 2H), 7.55 (d, J = 7.5 Hz, 2H), 7.41 (m, 2H),
7.36 (m, 2H), 3.98 (q, J = 8.0 Hz, 1H), 1.57 (d, J = 8.0 Hz, 3H);
13C NMR (125 MHz, CDCl3) δ 149.00, 140.53, 126.93, 126.92,
124.01, 119.85, 42.44, 18.18; MS, m/z (relative abudance) 180
(Mþ, 59), 165 (100), 139 (4), 89 (16), 82 (21), 76 (11), 63 (4).
9-Ethyl-9H-fluorene (7c): 1H NMR (500 MHz, CDCl3) δ 7.86
(d, J = 7.5 Hz, 2H), 7.60 (d, J = 7.5 Hz, 2H), 7.47 (m, 2H), 7.41
(m, 2H), 4.06 (t, J = 5.6 Hz, 1H), 2.19 (m, 2H), 0.83 (t, J = 7.5
Hz, 3H); 13C NMR (125 MHz, CDCl3) δ 147.72, 141.84, 127.37,
127.30, 124.81, 120.26, 48.98, 26.22, 10.26; MS, m/z (rel
abudance) 194 (Mþ, 67), 178 (20), 165 (100), 139 (9), 115 (6),
94 (6), 82 (17), 63 (6).
1
9-Phenyl-9H-fluorene (7d): H NMR (500 MHz, CDCl3):δ
7.84 (d, J = 7.6 Hz, 2H), 7.42 (t, J = 7.3 Hz, 2H), 7.32 (m, 7H),
7.13 (d, J = 6.8 Hz, 2H), 5.09 (s, 1H); 13C NMR (125 MHz,
CDCl3) δ 147.90, 141.60, 141.01, 128.68, 128.34, 127.30, 126.83,
125.33, 119.87, 54.44; MS, m/z (rel abundance) 242 (Mþ, 100),
215 (5), 165 (21), 119 (25), 106 (4).
General Procedure for the Synthesis of Substituted Azafuller-
enes 8a-d and 10a,b. A 300 equiv sample of the substituted
arylalkane was added to a degassed (5 vacuum/argon cycles)
solution of 1 (20 mg, 13.8 ꢀ 10-3 mmol) in HPLC grade ODCB
(40 mL). The mixture was heated at 160 °C for 4-9 h under
argon and the reaction was monitored by HPLC at 326 nm.
After distillation of ODCB at 55 °C under reduced pressure, the
crude mixture was washed 4-6 times with acetonitrile and/or
acetone (centrifugation at 1500 c/min) in order to remove the
remained substituted arylalkane. Chromatographic purifica-
tion, using hexane as eluent (the remaining azafullerene dimer
elutes first, followed by the more polar, green azafullerene
monoadduct), afforded 8a-d and 10a,b as black solids
(20-40% yield).
9-Azafullerenyl-9H-fluorene (8a): mp >360 °C; IR (KBr) v
(cm-1) 2914, 1510, 1446, 1421, 1183, 1091, 1021, 806, 738, 576,
523; UV-vis (CS2) λmax (nm) 378, 450, 595, 730, 817; MS (FAB)
m/z 888 (Mþ), 722 (C59Nþ); 1H NMR (500 MHz, CS2-CDCl3)
δ 8.47 (d, J = 7.6 Hz, 2H), 8.01 (d, J = 7.6 Hz, 2H), 7.65 (m,
2H), 7.55 (m, 2H), 6.13 (s, 1H); 13C NMR (125 MHz,
CS2-CDCl3) δ 156.29, 150.74, 148.52, 148.49, 148.39, 147.95,
9-Azafullerenylxanthene (10b). Xanthene (756 mg, 4.15 mmol)
was added to a degassed (5 vacuum/argon cycles) solution of 1 (20
mg, 13.8 ꢀ 10-3 mmol) in HPLC grade ODCB (40 mL). The
mixture was heated at 160 °C for 3 h under argon and the reaction
was monitored by HPLC at 326 nm. After distillation of ODCB at
55 °C under reduced pressure, the crude mixture was washed and
centrifuged 6 times with acetonitrile in order to remove the
remained xanthene. Chromatographic purification, using hexane
as eluent (the crude reaction mixture was loaded with CS2),
J. Org. Chem. Vol. 75, No. 12, 2010 4129