1864
E. David et al. / Tetrahedron Letters 49 (2008) 1860–1864
to afford 11 in 83% yield (3.04 g) as a yellow solid; mp 246–248 °C; 1H
14. Preparation and characterization data for 14: To a solution of
3-hydroxy-5,6,7-trimethyl-6-phenyl-5,6-dihydro-indolo[2,3-c]quinoline
13 (148 mg, 0.4 mmol, 2 equiv) in DMF (2 mL) were added 4-formyl-
1,3-benzenedisulfonic acid, disodium salt (62 mg, 0.2 mmol) and TFA
(0.2 mL). The reaction mixture was stirred at room temperature and
in the dark overnight. It was then heated at 120 °C in the dark for
24 h. The resulting reaction mixture was concentrated in vacuo. The
crude product was purified by flash chromatography (CHCl3/MeOH:
95:5) to afford 14 in 95% yield (178 mg) as a pearly blue solid;
mp >250 °C; 1H NMR (300 MHz, CD3OD): d 2.91 (s, 6H), 3.07 (s,
6H), 3.35 (s, 3H), 3.60 (s, 3H), 6.95 (d, 2H, J = 2.1 Hz), 7.11–7.27 (m,
6H), 7.34–7.52 (m, 13H), 7.69–7.75 (m, 2H), 8.21 (dd, 1H, J = 1.7,
7.9 Hz), 9.01 (d, 1H, J = 1.5 Hz); 13C NMR (125 MHz, CD3OD): d
24.5 (CH3), 24.6 (CH3), 31.2 (2CH3), 34.6 (2CH3), 67.1 (C), 67.2 (C),
96.6 (CH), 96.7 (CH), 105.6 (C), 105.7 (2C), 110.7 (2CH), 110.8 (CH),
117.4 (C), 117.5 (C), 120.3 (CH), 120.4 (CH), 120.5 (CH), 121.0 (CH),
121.2 (CH), 121.3 (CH), 122.7 (2CH), 122.9 (C), 123.6 (2C), 124.2
(2CH), 127.4 (CH), 128.8 (CH), 129.3 (2CH), 129.8 (CH), 129.9 (CH),
130.2 (2CH), 130.3 (CH), 131.6 (CH), 133.8 (C), 140.1 (2C), 140.3
(2C), 143.0 (2C), 146.8 (C), 148.7 (C), 152.4 (C), 152.5 (C), 155.8 (C),
158.2 (C), 158.3 (C); Anal. Calcd for C55H44N4O7S2, 1.5CHCl3,
H2O: C, 59.83; H, 4.22; N, 4.94; S, 5.95. Found: C, 60.54; H, 4.95; N,
4.59; S, 5.65; MS (ESI+): m/z = 935 (MH+), (ESIꢂ): m/z = 937
(MHꢂ).
NMR (300 MHz, CDCl3): d 2.18 (s, 3H), 3.17 (s, 3H), 4.12 (s, 3H),
4.51 (s, 3H), 6.88 (d, 2H, J = 8.1 Hz), 7.50–7.59 (m, 5H), 7.71–7.77
(m, 6H), 7.90 (d, 1H, J = 2.3 Hz), 8.62 (d, 1H, J = 8.3 Hz), 8.81 (d,
1H, J = 9.2 Hz); 13C NMR (75 MHz, CDCl3): d 21.3 (CH3), 32.4
(CH3), 42.7 (CH3), 57.1 (CH3), 100.9 (CH), 111.3 (CH), 119.0 (C),
119.7 (C), 122.7 (CH), 122.8 (CH), 125.0 (CH), 125.8 (CH), 125.9
(2CH), 128.2 (2CH), 129.0 (C), 130.0 (2CH), 130.1 (2CH), 130.4 (C),
130.7 (C), 131.8 (CH), 132.1 (CH), 137.2 (C), 138.3 (C), 144.4 (C),
144.7 (C), 146.0 (C), 162.2 (C); Anal. Calcd for C31H28N2O4S: C,
70.97; H, 5.38; N, 5.34; S, 6.11. Found: C, 71.17; H, 5.46; N, 5.28; S,
5.89; MS (ESI+): m/z = 353 (M+ꢂpTsOꢂ).
12. Preparation and characterization data for 12: To a suspension of 3-
methoxy-5-methyl-6-phenylindolo[2,3-c]quinolinium
tosylate 11
(3.04 g, 5.8 mmol) in anhydrous THF (40 mL) was added MeMgCl
(3 M in THF, 7.7 mL, 23.2 mmol, 4 equiv) at 0 °C under inert
atmosphere. The reaction was stirred at room temperature and in the
dark for a day. It was then poured into ice and acidified with a 2 M
HCl aqueous solution. The solution was extracted with CH2Cl2. The
resulting organic layer was washed with brine, dried over MgSO4,
filtered and solvents were removed under reduced pressure. The crude
product was purified by flash chromatography (cyclohexane/
CH2Cl2 = 7:3) to afford 12 in 95% yield (2.11 g) as a white solid;
mp 162–164 °C; 1H NMR (300 MHz, CDCl3): d 1.92 (s, 3H), 2.60 (s,
3H), 3.02 (s, 3H), 3.90 (s, 3H), 6.33 (d, 1H, J = 2.4 Hz), 6.50 (dd, 1H,
J = 2.4, 8.3 Hz), 7.24–7.29 (m, 3H), 7.36–7.45 (m, 3H), 7.64–7.67 (m,
2H), 7.91 (d, 1H, J = 8.3 Hz), 8.20 (m, 1H); 13C NMR (75 MHz,
CDCl3): d 20.9 (CH3), 30.7 (CH3), 32.2 (CH3), 55.4 (CH3), 63.9 (C),
99.2 (CH), 100.8 (CH), 107.2 (C), 109.3 (CH), 114.7 (C), 120.2 (CH),
120.6 (CH), 121.7 (CH), 122.4 (CH), 123.1 (C), 127.8 (CH), 128.5
(2CH), 128.6 (2CH), 137.8 (C), 138.4 (C), 143.3 (C), 145.2 (C), 158.5
(C); Anal. Calcd for C25H24N2O: C, 81.49; H, 6.57; N, 7.60. Found:
C, 81.42; H, 6.76; N, 7.48; MS (ESI+): m/z = 369 (MH+).
15. Absorbance and emission: UV–visible spectra were obtained using a
Cary 1 absorption spectrophotometer on a 1 cm path length quartz
cell. The steady-state emission spectra were recorded on a Photon
Technology International (PTI) SE-900M spectrofluorimeter and
recorded in a 1cm quartz cell. Emission quantum yield /L were
determined at 20 °C in methanol, according to Eq. 1,
Ref
ISL ð1 ꢂ 10ꢂOD
Þ
/
S
L
Ref
L
/
¼
ð1Þ
S
IRLef
ð1 ꢂ 10ꢂOD
Þ
13. Preparation and characterization data for 13: To a solution of 3-
methoxy-5,6,7-trimethyl-6-phenyl-5,6-dihydro-indolo[2,3-c]quinoline
12 (192 mg, 0.5 mmol) in anhydrous CH2Cl2 (5 mL) was added at
0 °C under inert atmosphere BBr3 (1 M in CH2Cl2, 1.5 mL, 1.5 mmol,
3 equiv). The reaction mixture was stirred at room temperature and in
the dark overnight. Methanol is then slowly added at 0 °C to quench
the residual BBr3. The reaction mixture was extracted with CH2Cl2.
The resulting organic layer was washed with a saturated NaHCO3
aqueous solution and brine, dried over MgSO4, filtered and solvents
were removed under reduced pressure. The crude product was purified
by flash chromatography (CH2Cl2/cyclohexane = 9:1) to afford 13 in
70% yield (125 mg) as a green solid; mp 144–146 °C; 1H NMR
(300 MHz, (CD3)2SO): d 1.86 (s, 3H), 2.53 (s, 3H), 2.97 (s, 3H), 6.16
(d, 1H, J = 2.2 Hz), 6.31 (dd, 1H, J = 2.2, 8.1 Hz), 7.14–7.21 (m, 2H),
7.34–7.49 (m, 4H), 7.58–7.61 (m, 2H), 7.69 (d, 1H, J = 8.1 Hz), 8.08
(m, 1H), 9.03 (s, 1H); 13C NMR (75 MHz, CDCl3): d 20.6 (CH3), 31.8
(CH3), 38.7 (CH3), 63.4 (C), 99.4 (CH), 103.7 (CH), 106.4 (C), 109.7
(CH), 112.0 (C), 119.9 (2CH), 121.4 (CH), 122.1 (CH), 122.2 (C),
127.7 (CH), 128.2 (2CH), 128.4 (2CH), 136.9 (C), 137.9 (C), 142.8 (C),
144.7 (C), 156.0 (C); HRMS (ESI+) calcd for C24H23N2O: 355.1810.
Found: 355.1811.
where IL, the emission intensity, was calculated from the spectrum
R
area IðkÞdk, OD represents the optical density at the excitation
wavelength. The superscripts ‘S’ and ‘Ref’ refer, respectively, to the
sample and to the standard. Rhodamine 101 (/RLef ¼ 1 in methanol)
was used as the standard.The luminescence lifetime of the complexes
was performed after irradiation at k = 400 nm obtained by the second
harmonic of a Titanium: Sapphire laser (picosecond Tsunami laser
spectra physics 3950-M1BB) at a 8MHZ repetition rate. The Fluotime
200 from AMS technologies is used for decay acquisition. It consists
of a GaAs microchannel plate photomultiplier tube (Hamamatsu
model R3809U-50) followed by a time-correlated single photon
counting system from picoquant (PicoHarp300). The ultimated time
resolution of the system was closed to 30 ps. These measurements
were recorded using the technical support from the chemistry plat-
form ‘NanoBio campus’ in Grenoble (France).
16. Karstens, B.; Kobs, K. J. Phys. Chem. 1980, 84, 1871–1872.
17. Selanger, K. A.; Falnes, J.; Sikkeland, T. J. Phys. Chem. 1977, 81,
1960–1963.
18. Frank, A. J.; Otvos, J. W.; Calvin, M. J. Phys. Chem. 1979, 83, 716–
722.