194=[426]
J. Simokaitiene et al.
(KBr), cmꢁ1: 3053; 2957, 2926, 2849; 1687; 1586; 1230. MS(APCIþ, 20 V), m=z, %:
308 ([MþH]þ, 100).
3-(9-Ethylcarbazol-3-yl-iminomethyl)-9-ethylcarbazole (7). 3-Formyl-9-ethylcar-
bazole (5) (1.0 g, 4.48 mmol) and 3-amino-9-ethylcarbazole (4) (1.4 g, 96.7 mmol)
were dissolved in 10 ml of ethanol. The mixture was refluxed under N2 for 24 h. Then
the reaction mixture was cooled down, the product precipitated out and was recov-
ered by filtration. The yield of 7 (of yellow amorphous material) was 1.6 g. 1H NMR
(CDCl3, 100 MHz) d, ppm: 0.36 (t, 6H, CH3); 4.10–4.34 (m, 4H, CH2); 7.11–8.64 (m,
14H, ar); 8.75 (s, 1H, N CH). IR (KBr), cmꢁ1: 3048, 2967, 2863, 1627; 1614; 1597,
=
1472, 1447, 1281, 1238, 1153, 1132, 1121, 842, 819, 803, 783, 766, 744, 726.
MS(APCIþ, 20 V), m=z, %: 416 ([MþH]þ, 100).
3-(9-Ethylcarbazol-3-yl-iminomethyl)-10-(2-ethylhexyl)phenothiazine (8). 3-
Formyl-10-(2-ethylhexyl)phenothiazine (3) (0.89 g, 2.6 mmol) and 3-amino-9-ethyl-
carbazole (4) (0.82 g, 3.9 mmol) were dissolved in 30 ml of methanol. The reaction
mixture was refluxed under N2 for 2 h. Then the solvent was distilled under reduced
pressure and the crude product was purified by silica gel column chromatography
using hexane=ethyl acetate (vol. ratio 7:1) as an eluent. The yield of 8 (yellow
1
amorphous material) was 0.4 g. H NMR (CDCl3, 100 MHz) d, ppm: 0.86–1.02
(m, 6H, CH3); 1.41–1.61 (m, 8H, CH2); 1.73–1.90 (m, 1H, CH); 1.95–2.13 (t, 3H,
N-CH2-CH3); 3.80–3.88 (d, 2H, N-CH2-CH; 4.36–4.46 (q, 2H, N-CH2-CH3);
6.95–8.23 (m, 14H, ar); 8.58 (s, 1H, N CH). IR (KBr), cmꢁ1: 3058, 2959, 2826,
=
2857, 1633, 1612, 1598, 1573, 1460, 1333, 1249, 1238, 1227, 1162, 1334, 1123,
1102, 780, 764, 747, 727. MS(APCIþ, 20 V), m=z, %: 532 ([MþH]þ, 100).
N-[Bis(4-dimethylaminophenyl)methylidene]-N-(9-ethylcarbazol-3-yl)amine (9).
3-Amino-9-ethylcarbazole (4) (0.6 g, 2.85 mmol), 4,40-bis(dimethylamino)benzophe-
none (6) (1.54 g, 5.7 mmol) and 1,4-diazabicyclo[2.2.2]octane (0.96 g, 8.56 mmol)
were dissolved in 40 ml of 1,2-dichlorobenzene. Then TiCl4 (0.86 g, 4.55 mmol) was
added drop-wise to the solution. The reaction mixture was stirred at 130ꢂC under N2
for 24 h. Then the reaction mixture was cooled down to the room temperature,
1,4-diazabicyclo[2.2.2]octane precipitated out and was removed by filtration. Then
hexane was added to the solution and excess of 6 precipitated out. When the precipi-
tate was filtered off, the solvents were distilled under reduced pressure and the crude
product was purified by silica gel column using hexane=acetone (vol. ratio 1:6) as an
1
eluent. The yield of 9 (orange amorphous material) was 0.32 g. H NMR (CDCl3,
100 MHz) d, ppm: 1.38–1.48 (t, 3H, CH3); 2.94 (s, 6H, CH3); 3.18 (s, 6H, CH3);
4.33–4.38 (q, 2H, CH2) 6.53–8.10 (m, 15H, ar). IR (KBr), cmꢁ1: 3447, 3041, 2888,
2859, 2807, 1869, 1737, 1712, 1609, 1584, 1360, 1276, 12428, 1211, 1190, 1182,
1168, 1137, 1120, 823, 811, 782, 749, 685. MS(APCIþ, 20V), m=z, %: 461 ([MþH]þ,
100).
Results and Discussion
Carbazole-based imines (7–9) were prepared as described in Scheme 1 via the nucleo-
philic addition reaction of the commercially available 3-amino-9-ethylcarbazole (4)
with an excess of the corresponding aldehyde (3 or 5) or ketone 6. The reactions
of amine with the aldehydes proceeded without catalyst. TiCl4 and 1,4-diazabicy-
clo[2.2.2]octane were used for the acceleration of the reaction between 4 and 4,
40-bis(dimethylamino)benzophenone (6). The starting aldehyde 3-formyl-10-(2-ethyl-
hexyl)phenothiazine (3) was prepared from 10H-phenothiazine (1) by two step