H.-Y. Wang et al. / Dyes and Pigments 95 (2012) 268e274
269
available and used without further purification. Melting points
2.4.2. 5-Amino-2-(4-bromophenyl)-chromeno[4,3,2-de][1,6]
were recorded on electrothermal digital melting point apparatus
and were uncorrected. 1H and spectra were recorded at 295 K on
a Bruker Advance DPX-400 MHz spectrometer using DMSO-d6 as
solvent and TMS as internal standard. UVevis spectra were recor-
ded on a Shimadzu UV-2501PC spectrometer. Fluorescence spectra
were obtained on a Hitachi FL-4500 spectrofluorometer. High
resolution mass spectroscopy (HRMS) data were measured using
microTOF-Q(ESI) instrument. Thermal properties was performed
under nitrogen on a SDT 2960 (heating rate of 10 ꢁC minꢀ1). Cyclic
voltammetry was carried on a Chi 1200 A electrochemical analyzer
with three-electrode cell (Platinum was used as working electrode
and as counter electrode, and SCE (saturated calomel electrode) as
reference electrode) in CH2Cl2 solution in the presence of TBAHFP
(tetrabutylammonium hexafluorophosphate) (0.10 mol Lꢀ1) as
supporting electrolyte.
naphthyridine-4-carbonitrile (7b)
Yield (0.63 g) 76%, Yellow crysta, M.p. > 300 ꢁC. 1H NMR
(400 MHz, DMSO-d6):
d
8.59 (d, J ¼ 7.2 Hz, 1H), 8.46 (d, J ¼ 8.8 Hz,
1H), 8.37 (s, 1H), 7.82 (d, J ¼ 12.0 Hz, 1H), 7.73e7.66 (m, 3H),
7.53e7.47 (q, 4H).
HRMS (ESI): m/z calcd. for C21H11N4BrO, 415.0189; found,
413.2552.
2.4.3. 5-Amino-9-fluoro-2-(4-bromophenyl)-chromeno[4,3,2-de]
[1,6]naphthyridine-4-carbonitrile (7c)
Yield (0.52 g) 60%, Yellow solid, M.p. > 300 ꢁC. 1H NMR
(400 MHz, DMSO-d6):
d 8.71e8.68 (m, 1H), 8.40 (s, 3H), 7.83e7.81
(d, J ¼ 8.4, 2H), 7.57e7.52 (m, 3H), 7.44e7.39 (m, 1H) ppm.
HRMS [Found: m/z 423.0020 (Mþ), Calcd for C21H10N4BrFO: M,
432.0022].
2.4.4. 5-Amino-9-methyl-2-(4-bromophenyl)-chromeno[4,3,2-de]
[1,6]naphthyridine-4-carbonitrile (7d)
2.2. N,N-diphenyl-4-bromoaniline (2)
Yield (0.47 g) 55%, Yellow solid, M.p. > 300 ꢁC. 1H NMR
Compound 1 (27.1 g, 120 mmol) and N-Bromosuccinimide (NBS;
21.4 g, 120 mmol) were dissolved in 500 mL of CCl4. The solution
was refluxed for 4 h. The precipitated succinimide was filtered, and
the solvent was evaporated from the solution. The remaining gray
oil was recrystallized from ethanol. The obtained white crystalline
powder was dried in a vacuum (34.3 g 94%). White, 1H NMR
(400 MHz, DMSO-d6):
d 8.42e8.35 (m, 4H), 7.83e7.81 (m, 2H),
7.53e7.51 (m, 2H), 7.43e7.40 (m, 1H), 2.47 (s, 3H) ppm.
HRMS [Found: m/z 428.0270 (Mþ), Calcd for C22H13N4BrO: M,
428.0273].
2.4.5. 5-Amino-2-(4-bromophenyl)-10-bromochromeno[4,3,2-de]
[1,6]naphthyridine-4-carbonitrile (7e)
(400 MHz, CDCl3):
d 7.35e7.20 (m, 6H), 7.11e6.99 (m, 6H),
6.97e6.90 (m, 2H).
Yield (0.59 g) 60%, Yellow solid, M.p. > 300 ꢁC. 1H NMR
(400 MHz, DMSO-d6):
d
8.64 (d, J ¼ 8.0 Hz, 1H), 8.40e8.371 (m, 3H),
2.3. 4-(Diphenylamino)phenylboronic acid (3)
7.82e7.80 (m, 2H), 7.71 (s, 1H), 7.58e7.51 (m, 3H).
HRMS [Found: m/z 493.9203 (Mþ), Calcd for C21H10N4Br2O: M,
493.9201].
A solution of 2 (3.3 g, 10.0 mmol) in anhydrous THF (50 mL) was
cooled to ꢀ78 ꢁC. n-BuLi (2.5 mol Lꢀ1 in hexane, 4.8 mL, 12.0 mmol)
was slowly added dropwise. After complete addition, the reaction
mixture was stirred for another 1 h. Then, triisopropyl borate
(3.5 mL, 15.0 mmol) was added at once. The mixture was allowed to
warm to room temperature for 15 h. The reaction was finally
quenched with HCl (2.0 mol Lꢀ1, 40 mL) and the mixture was
poured into a large amount of water. After extraction with CH2Cl2
(3 ꢂ 20 mL), The organic layer was washed with brine, dried over
MgSO4, concentrated. Further purification by silica gel column
chromatography (petroleum ether/dichloromethane, 2/1, v/v)
afforded 3 as a white solid (1.61 g, 54%). White, 1H NMR (300 MHz,
2.5. General procedure for the synthesis of compounds (8 and 9)
Under a nitrogen atmosphere, a mixture of compounds (7)
(1.0 mmol), Pd(PPh3)4 catalyst (0.04 mmol) and the corresponding
triphenylamine (or benzene) boronic acid was stirred in dry
toluene (15 mL). Then, 2 mol Lꢀ1 K2CO3 (aq) solution (2 mL) was
added via syringe. The reaction mixture was heated to reflux
for 72 h. After cooling, the product was extracted with DCM,
washed with water, dried over MgSO4, filtered, concentrated and
further purified by column chromatography (silica gel, hexane/
dichloromethane, 10/1, v/v). The pure compounds 8 (or 9) were
obtained.
d6-DMSO):
d
7.84 (s, 2H), 7.65e7.68 (d, J ¼ 8.4 Hz, 2H), 7.31 (t,
J ¼ 7.8 Hz, 4H), 7.00-7.08 (m, 6H), 6.87-6.89 (d, J ¼ 8.1 Hz, 2H).
2.4. General procedure for the synthesis of compounds 7
2.5.1. 5-Amino-2-(40-(diphenylamino)biphenyl-4-yl)-9-
fluorochromeno[4,3,2-de][1,6]naphthyridine-4-carbonitrile (8a)
Compounds 7aee were synthesized according to methods
Yield (0.48 g) 84%, Yellow solid, 1H NMR (400 MHz, DMSO-d6):
described in literature [39].
A
mixture of substitution-2-
d
8.75e8.68 (m, 2H), 8.52e8.50 (d, J ¼ 8.0, 1H), 8.42e8.38 (m, 3H),
hydroxyacetophenone (2.0 mmol), aromatic aldehyde (2.0 mmol),
malononitrile (4.0 mmol) and 0.03 g of silica gel was stirred in
water (2 mL) at 80 ꢁC. After 2 h reaction, the mixture was filtered
and then concentrated. The precipitate was collected and purified
by 95% EtOH-DMF (10:1). The analytical data for represent
compounds are shown below.
7.89e7.87 (d, J ¼ 8.0 Hz, 1H), 7.83e7.81 (d, J ¼ 8.0 Hz, 2H), 7.77e7.75
(d, J ¼ 8.4 Hz, 1H), 7.60e7.52 (m, 5H), 7.44e7.34 (m, 4H), 7.12e7.05
(m, 5H) ppm.
HRMS [Found: m/z 578.2127 (Mþ), Calcd for C39H25N5O: M,
579.2059].
2.5.2. 5-Amino-2-(40-(diphenylamino)biphenyl-4-yl)-9-
2.4.1. 5-Amino-2-phenyl-chromeno[4,3,2-de][1,6]naphthyridine-4-
carbonitrile (7a)
methylchromeno[4,3,2-de][1,6]naphthyridine-4-carbonitrile (8b)
Yield (0.49 g) 82%, Yellow solid, 1H NMR (400 MHz, DMSO-d6):
Yield (0.46 g) 69%, Yellow crystal, Melting point (M.p.) > 300 ꢁC.
d
8.52e8.50 (d, J ¼ 8.0 Hz, 2H), 8.46 (s, 1H), 8.43e8.38 (d, J ¼ 8.4 Hz,
1H NMR (400 MHz, DMSO-d6):
d
8.63e8.61 (dd, J1 ¼ 1.2 Hz,
2H), 7.88e7.86 (m, 2H), 7.83e7.81 (d, J ¼ 8.0 Hz, 1H), 7.76e7.74 (d,
J ¼ 8.4 Hz, 2H), 7.53e7.51 (m, 3H), 7.42e7.40 (m, 1H), 7.38e7.34 (t,
J2 ¼ 8.0 Hz, 1H), 8.45e8.44 (d, J ¼ 2.0 Hz, 1H), 8.43e8.42 (d,
J ¼ 1.6 Hz, 1H), 8.39 (s, 1H), 7.74e7.70 (t, 1H), 7.63e7.60 (m, 3H),
7.60e7.47 (m 4H).
J
¼
8.0 Hz, 4H), 7.14e7.08 (m, 7H), 2.47 (s, 3H) ppm.
HRMS [Found: m/z 596.1890 (M-H), Calcd for C39H24N5FO: M,
HRMS (ESI): m/z calcd. for C21H12N4O, 337.1084; found, 337.1010.
597.1965].