C. Qin et al. / Dyes and Pigments 94 (2012) 553e560
555
anhydrous magnesium sulfate. After removal of the solvent under
(150 MHz, CDCl3)
d: 181.94, 181.23, 158.19, 148.42, 145.59, 145.57,
reduced pressure, the residue was purified by column chromatog-
145.46, 144.87, 144.74, 144.08, 141.23, 133.52, 133.24, 130.03, 129.4,
126.46, 126.07, 125.82, 125.07, 122.7, 121.87, 117.84, 20.86 ppm.
raphy on silica gel (ethyl acetate/hexane,1/10, v/v) to give a pale red
solid (6.0 g, 96% yield). 1H NMR (600 MHz, DMSO-d6)
d
: 9.79 (s, 1H),
7.91 (s, 1H), 7.38 (s, 1H) ppm. 13C NMR (150 MHz, DMSO-d6)
d:
2.4.6. 2-Cyano-3-{6-{2-{4-[N,N-bis(4-methylphenyl)amino]
phenyl}thiophene-5-yl}-4H-cyclopenta[2,1-b:3,4-b0]dithiophen-4-
one-2-yl}acrylic acid (HIQ2)
182.04, 180.05, 157.05, 147.27, 146.14, 143.56, 140.61, 129.44, 124.76,
118.15 ppm. MALDI-MS calcd: 297.88, found: 297.98.
HIQ2 was synthesized according to the procedure described for
HIQ1 and was obtained as a black powder (0.15 g, 60% yield). FT-IR
(KBr, vmax/cmꢀ1): 3420, 3025, 2917, 2852, 2210, 1709, 1676, 1575,
2.4.3. 6-{4-[N,N-Bis(4-methylphenyl)amino]phenyl}-4H-
cyclopenta[2,1-b:3,4-b0] dithiophen-4-one-2-carbaldehyde
A mixture of 6-bromo-4H-cyclopenta[2,1-b:3,4-b0]dithiophen-
4-one-2-carbaldehyde (0.1 g, 0.35 mmol), 4-tributylstannyl-N,N-
bis(4-methylphenyl)aniline (0.22 g, 0.4 mmol), Pd(PPh3)4 (10 mg)
and anhydrous toluene (20 mL) was refluxed for 24 h under argon.
The crude product was extracted into dichloromethane, and the
organic layer was washed with water and dried over anhydrous
magnesium sulfate. After removal of the solvent under reduced
pressure, the residue was purified by column chromatography on
silica gel (ethyl acetate/hexane, 1/8, v/v) to yield a black-red solid
1430, 1262, 931, 813, 790, 761. 1H NMR (600 MHz, DMSO-d6)
d: 8.06
(s, 1H), 7.58 (s, 1H), 7.49 (d, J ¼ 8.4 Hz, 2H), 7.39 (d, J ¼ 4.2 Hz, 1H),
7.33 (d, J ¼ 4.2 Hz, 1H), 7.29 (s, 1H), 7.13 (d, J ¼ 8.4 Hz, 4H), 6.94 (d,
J ¼ 8.4 Hz, 4H), 6.87 (d, J ¼ 8.4 Hz, 2H), 2.27 (s, 6H) ppm. 13C NMR
(150 MHz, DMSO-d6) d: 181.89, 163.91, 154.33, 148.01, 146.56, 144.7,
143.85, 143.76, 143.17, 141.3, 140.99, 140.91, 133.96, 133.32, 130.62,
127.73, 126.8, 126.6, 125.23, 124.02, 121.77, 119.79, 117.39, 79.66,
20.89 ppm. HRMS (FABþ, m/z): calcd for C37H24N2O3S3, 640.0949;
found, 640.0925.
(0.12 g, 73% yield). 1H NMR (600 MHz, CDCl3)
d: 9.76 (s, 1H), 7.58 (s,
1H), 7.36 (dd, J ¼ 6.6, 1.8 Hz, 4H), 7.16 (s, 1H), 7.11 (d, J ¼ 8.4 Hz, 4H),
2.4.7. 6-{5-{4-[N,N-Bis(4-methylphenyl)amino]phenyl}-3,4-
ethylenedioxythiophene-2-yl}-4H-cyclopenta[2,1-b:3,4-b0]
7.03 (m, 4H), 6.99 (m, 2H), 2.33 (s, 6H) ppm. 13C NMR (150 MHz,
CDCl3)
d
: 181.94, 181.76, 158.76, 152.41, 149.15, 145.9, 145.07, 144.45,
dithiophen-4-one-2-carbaldehyde
143.81, 141.03, 133.68, 130.13, 129.44, 126.29, 125.35, 125.3, 121.29,
115.98, 20.88 ppm.
A mixture of 6-bromo-4H-cyclopenta[2,1-b:3,4-b0]dithiophen-
4-one-2-carbaldehyde (0.1 g, 0.35 mmol), 4-[5-tributylstannyl-3,4-
ethylenedioxythiophene-2-yl]-N,N-bis(4-methylphenyl)aniline
(0.28 g, 0.4 mmol), Pd(PPh3)4 (10 mg) and anhydrous toluene
(20 mL) was refluxed for 24 h under argon. The crude product was
extracted into dichloromethane, and the organic layer was washed
with water and dried over anhydrous magnesium sulfate. After
removal of the solvent under reduced pressure, the residue was
purified by column chromatography on silica gel (ethyl acetate/
hexane, 1/5, v/v) to yield a black-red solid (0.15 g, 68% yield). 1H
2.4.4. 2-Cyano-3-{6-{4-[N,N-bis(4-methylphenyl)amino]phenyl}-
4H-cyclopenta[2,1-b:3,4-b0]dithiophen-4-one-2-yl}acrylic acid
(HIQ1)
To a stirred solution of 6-{4-[N,N-bis(4-methylphenyl)amino]
phenyl}-4H-cyclopenta[2,1-b:3,4-b0]dithiophen-4-one-2-
carbaldehyde (27 mg, 0.55 mmol) and cyanoacetic acid (94 mg,
1.1 mmol) in chloroform (5 mL) was added piperidine (188 mg,
2.2 mmol). The reaction mixture was refluxed under argon for 12 h
and then acidified with 2 M aqueous hydrochloric acid (10 mL). The
crude product was extracted into chloroform, and the organic layer
was washed with water and dried over anhydrous magnesium
sulfate. After removal of the solvent under reduced pressure, the
residue was purified by flash chromatography with chloroform and
methanol/chloroform (1/10, v/v) in turn as eluents to yield a black
powder (23 mg, 76% yield). FT-IR (KBr, vmax/cmꢀ1): 3416, 3026,
2919, 2853, 2219, 1709, 1578, 1430, 1359, 1320, 1259, 1212, 1093,
NMR (600 MHz, CDCl3)
(d, J ¼ 7.8 Hz, 4H), 7.02 (m, 6H), 4.41 (s, 2H), 4.36 (s, 2H), 2.32 (s, 6H)
ppm. 13C NMR (150 MHz, CDCl3)
: 181.84, 181.56, 159.14, 147.5,
d: 9.74 (s, 1H), 7.53 (m, 3H), 7.16 (s, 1H), 7.08
d
145.28, 144.84, 144.79, 143.23, 142.7, 141.08, 139.61, 137.22, 133.02,
129.96, 129.46, 126.93, 124.94, 124.88, 121.94, 117.69, 115.89, 107.95,
65.15, 64.62, 20.85 ppm.
2.4.8. 2-Cyano-3-{6-{2-{4-[N,N-bis(4-methylphenyl)amino]
phenyl}-3,4-ethylenedioxy thiophen-5-yl}-4H-cyclopenta[2,1-b:3,4-
b0]dithiophen-4-one-2-yl}acrylic acid (HIQ3)
816, 767. 1H NMR (600 MHz, DMSO-d6)
d: 8.15 (s, 1H), 7.65 (s, 1H),
7.51 (s, 2H), 7.37 (s, 2H), 7.14(d, J ¼ 7.8 Hz, 4H), 6.96 (d, J ¼ 7.8 Hz,
HIQ3 was synthesized according to the procedure described for
HIQ1 and was obtained as a black powder (52 mg, 55% yield). FT-IR
(KBr, vmax/cmꢀ1): 3397, 3024, 2920, 2857, 2211, 1713, 1578, 1493,
4H), 6.85(d, J ¼ 7.8 Hz, 2H), 2.27 (s, 6H) ppm. 13C NMR (150 MHz,
DMSO-d6) d: 182.12, 163.99, 155.87, 151.12, 148.49, 145.86, 144.52,
143.02, 140.77, 140.02, 133.6, 130.67, 128.94, 126.66, 125.92, 125.47,
121.25, 119.14, 116.56, 79.65, 20.91 ppm. HRMS (FABþ, m/z): calcd
for C33H22N2O3S2, 558.1072; found, 558.1061.
1437, 1360, 1280, 1082, 813, 762. 1H NMR (600 MHz, DMSO-d6)
d:
8.08 (s, 1H), 7.61 (s, 1H), 7.50 (s, 2H), 7.12 (m, 5H), 6.93 (m, 6H), 4.45
(s, 2H), 4.37 (s, 2H), 2.27 (s, 6H) ppm. 13C NMR (150 MHz, DMSO-d6)
d: 181.84, 163.6, 155.8, 147.08, 145.69, 144.79, 143.55, 142.46, 141.33,
2.4.5. 6-{5-{4-[N,N-Bis(4-methylphenyl)amino]phenyl}thiophene-
2-yl}-4H-cyclopenta
140.83, 140.2, 139.82, 138.03, 130.58, 128.52, 127.13, 125.25, 125.02,
121.97, 119.37, 115.7, 115.52, 107.81, 79.65, 65.67, 65.06, 20.88 ppm.
HRMS (FABþ, m/z): calcd for C39H26N2O5S3, 698.1004; found,
698.1011.
2.4.5.1. [2,1-b:3,4-b0]dithiophen-4-one-2-carbaldehyde. A mixture
of
6-bromo-4H-cyclopenta[2,1-b:3,4-b0]dithiophen-4-one-2-
carbaldehyde (0.19 g, 0.65 mmol), 4-(2-(tributylstannyl)thio-
phene-5-yl)-N,N-bis(4-methylphenyl)aniline (0.52 g, 0.8 mmol),
Pd(PPh3)4 (10 mg) and anhydrous toluene (20 mL) was refluxed for
24 h under argon. The crude product was extracted into dichloro-
methane, and the organic layer was washed with water and dried
over anhydrous magnesium sulfate. After removal of the solvent
under reduced pressure, the residue was purified by column
chromatography on silica gel (ethyl acetate/hexane, 1/8, v/v) to
yield black-red solid (0.28 g, 75% yield). 1H NMR (600 MHz, CDCl3)
3. Results and discuss
3.1. Synthesis
The general synthetic routes to HIQ1, HIQ2 and HIQ3 are depicted
in Fig. 2. 4H-cyclopenta[2,1-b:3,4-b0]dithiophen-4-one was formyla
ted with phosphorus oxychloride in DMF to afford 4H-cyclopenta[2,1-
b:3,4-b0]dithiophen-4-one-2-carbaldehyde in excellent yield. The carb
aldehyde was brominated with NBS to give 6-bromo-4H-cyclopenta
[2,1-b:3,4-b0]dithiophen-4-one-2-carbaldehyde in high yield.4-tribu
d: 9.77 (s,1H), 7.40 (d, J ¼ 6.6 Hz, 2H), 7.18 (d, J ¼ 3.6 Hz, 2H), 7.13 (m,
2H), 7.09 (d, J ¼ 8.4 Hz, 4H), 7.03 (m, 6H), 2.32 (s, 6H) ppm. 13C NMR