404
P. Thirumurugan, P.T. Perumal / Dyes and Pigments 88 (2011) 403e412
of green chemical techniques in organic synthesis [22e24], herein,
we report a simple and facile one pot procedure for the synthesis of
1,2,4-triazine derivatives under reflux condition.
(m, 1H, eAreH), 8.13 (d, 1H, eAreH), 8.39 (d, 1H, J ¼ 15.3 Hz,
eAreH), 8.69 (d, 1H, J ¼ 7.6 Hz, eAreH), 8.89 (d, 1H, J ¼ 3.8 Hz,
eAreH); 13C NMR (75 MHz, DMSO-d6): 118.5, 119.4, 127.8, 128.3,
129.0, 129.1, 129.7, 130.5, 135.3, 135.9, 139.2, 143.2, 144.6, 145.6,
145.9, 148.8, 151.4, 152.6, 159.1; MS (EI): m/z 363.27 [Mþ þ Hþ];
C24H18N4. Anal. Calcd for C24H18N4. C 79.54 H 5.01 N 15.46. Found:
C 79.49 H 5.03 N 15.49.
2. Experimental
2.1. General
All the substituted aldehydes, biacetyl, and all the substituted
cyanopyridines were purchased from Aldrich Chemicals. Piperi-
dine and other reagents were purchased from S. D. Fine. Chem.
India Limited. Methanol was distilled with Mg/I2 under nitrogen
and stored over 3Aꢀ molecular sieves. IR measurements were
done as KBr pellets for solids using Perkin Elmer Spectrum RXI FT-
IR. 1H and 13C NMR spectra were recorded in CDCl3 using TMS as
internal standard with JEOL 500 MHz and Bruker 300 MHz high
resolution NMR spectrometer respectively. Multiplicities were
abbreviated as follows: singlet (s), doublet (d), triplet (t), multiplet
(m), and broad (br). Mass spectra were recorded using Electron
Spray Ionization method with Thermo Finnigan mass spectrom-
eter. Melting points were determined in capillary tubes and are
uncorrected. Analytical TLC was performed on precoated plastic
sheets of silica gel G/UV-254 of 0.2 mm thickness (Macherey-
Nagel, Germany). Elemental analysis data were recorded using
Thermo Finnigan FLASH EA 1112 CHN. The electronic spectral
measurements were carried out in PerkineElmer Lambda 35
double beam spectrometer at room temperature. The steady state
emission spectra were recorded on Hitachi 650e40 spectrofluo-
rometer at room temperature. Time-resolved fluorescence
measurements were determined using picosecond laser excited
Horibajobinyvon time correlated single photon counting spectro-
fluorometer. The excitation source was a tunable Ti-sapphire laser
(Tsunami, Spectrometer, USA) with a pulse width of <2 ps and
repetition rate of 82 MHz, AreH. The sample was excited at its
corresponding wavelength and the emission was monitored
between 400 to 600 nm using a MCP-PMT detector. Decay traces
were deconvulated using a non-linear least-squares analysis using
IBH software.
2.2.2. 3b. 5,6-bis[(E)-2-(4-methylphenyl)vinyl]-3-
pyridin-2-yl-1,2,4-triazine (Table 1, entry 2)
Yellow solid; mp 168e170 ꢀC; Rf 0.83 (40% AcOEt/Petroleum
ether); IR (KBr): 1065, 1180, 1363, 1400, 1481, 1623 cmꢁ1 1H NMR
;
(500 MHz, CDCl3):
d 2.40 (s, 3H, AreCH3), 2.41 (s, 3H, AreCH3),
7.22e7.26 (m, 4H, eAreH), 7.30e7.39 (m, 2H, eAreH), 7.54e7.60
(m, 2H, eAreH), 8.10 (d, 1H, J ¼ 15.3 Hz, eAreH), 8.30 (d, 1H,
J ¼ 15.3 Hz, eAreH), 8.43 (d, 1H, J ¼ 6.1 Hz, eAreH), 8.82 (d, 1H,
J ¼ 4.6 Hz, eAreH); 13C NMR (75 MHz, DMSO-d6): 21.4, 21.5, 117.9,
118.8,124.0,125.1,127.7,128.2, 129.6,129.7,132.9, 133.4,137.0,138.3,
139.7, 140.7, 142.6, 150.3, 151.4, 152.2, 153.4, 160.3; MS (EI): m/z
391.20 [Mþ þ Hþ]; Anal. Calcd for C26H22N4. C 79.97 H 5.68 N 14.35.
Found: C 79.87 H 5.66 N 14.29.
2.2.3. 3c. 5,6-bis[(E)-2-(4-methoxyphenyl)vinyl]-3-
pyridin-2-yl-1,2,4-triazine (Table 1, entry 3)
Yellow solid; mp 62e64 ꢀC; Rf 0.64 (40% AcOEt/Petroleum
ether); IR (KBr): 822, 1026, 1171, 1278, 1301, 1508, 1602 cmꢁ1 1H
;
NMR (500 MHz, CDCl3):
d 3.84 (s, 6H, AreOCH3), 6.92 (d, 5H,
J
¼
9.2 Hz, eAreH), 7.22e7.30 (m, 2H, eAreH), 7.59 (d,
2H, J ¼ 16.1 Hz, eAreH), 7.63 (d, 2H, J ¼ 16.1 Hz), 8.09 (d, 1H,
J ¼ 16.1 Hz, eAreH), 8.30 (d, 1H, J ¼ 16.1 Hz, eAreH), 8.71 (d,
1H, J ¼ 2.3 Hz, eAreH), 8.81 (d, 1H, J ¼ 2.3 Hz, eAreH), 8.84 (d,
1H, J ¼ 1.6 Hz, eAreH); 13C NMR (75 MHz, DMSO-d6): 55.3, 55.4,
117.2, 117.6, 123.8, 125.0, 127.2, 128.4, 129.0, 129.2, 129.5, 129.9,
130.8, 136.4, 137.0, 137.7, 142.0, 147.4, 150.2, 151.3, 152.1, 155.5,
160.7; MS (EI): m/z 423.27 [Mþ
C26H22N4O2. C 73.92 H 5.25 N 13.26. Found: C 73.84 H 5.23 N
13.23.
þ
Hþ]; Anal. Calcd for
2.2.4. 3d. 5,6-bis[(E)-2-(3,4-dimethoxyphenyl)vinyl]-
3-pyridin-2-yl-1,2,4-triazine (Table 1, entry 4)
2.2. General procedure for the synthesis of bisaryl-3-
pyridinyl-1,2,4-triazine derivatives (3ael)
Yellow solid; mp 180e182 ꢀC; Rf 0.35 (40% AcOEt/Petroleum
ether); IR (KBr): 963, 1019, 1140, 1260, 1511, 1624 cmꢁ1 1H NMR
;
Method: A
(500 MHz, CDCl3): d 3.90 (s, 6H, AreOCH3), 3.92 (s, 3H, AreOCH3),
A mixture of cinnamil (1.0 mmol) and pyridine carboxtrisami-
drazone (1.0 mmol) in methanol (30 mL) was refluxed for the
appropriate time as described in Table 1. After completion of the
reaction, as indicated by TLC, the precipitated solid was filtered,
washed with water and dried. The obtained crude solid was puri-
fied further by recrystalization with ethanol.
3.93 (s, 3H, AreOCH3), 6.88 (d, 2H, J ¼ 8.4 Hz, eAreH), 7.15e7.23 (m,
4H, eAreH), 7.25e7.31 (m, 2H, eAreH), 7.41e7.43 (m, 1H, eAreH),
7.87e7.90 (m, 1H, eAreH), 8.02 (d, 1H, J ¼ 16.2 Hz, eAreH), 8.29 (d,
1H, J ¼ 15.3 Hz, eAreH), 8.65 (d, 1H, ¼ 7.6 Hz, eAreH), 8.87 (d, 1H,
J ¼ 4.6 Hz, eAreH); 13C NMR (75 MHz, DMSO-d6): 55.9, 56.0, 110.2,
110.7, 111.3, 117.1, 117.8, 121.5, 122.2, 123.9, 125.0, 128.7, 129.3, 137.0,
138.0, 142.3, 149.2, 150.2, 150.5, 151.1, 151.3, 152.1, 153.4, 160.0; MS
(EI): m/z 483.20 [Mþ þ Hþ]; Anal. Calcd for C28H26N4O4. C 69.70 H
5.43 N 11.61. Found: C 69.81 H 5.45 N 11.57.
Method: B
A mixture of cinnamil (1.0 mmol) and pyridine carboxtrisami-
drazone (1.0 mmol) in methanol (2 mL) was irradiated in a micro-
wave oven (BPL BMG 800 TS model) at 80 W for the appropriate
time displayed in Table 1. After completion of the reaction, as
indicated by TLC, the precipitated solid was filtered, washed with
water and then dried. The obtained crude product was recrystal-
lized with ethanol.
2.2.5. 3e. 5,6-bis[(E)-1-napthylvinyl]-3-pyridin-2-
yl-1,2,4-triazine (Table 1, entry 5)
Yellow solid; mp 68e70 ꢀC; Rf 0.82 (40% AcOEt/Petroleum
ether); IR (KBr): 1024, 1251, 1395, 1465, 1621 cmꢁ1 1H NMR
;
(500 MHz, CDCl3):
d 6.88e6.93 (m, 6H, eAreH), 7.22e7. 32 (m, 4H,
eAreH), 7.41e7.43 (m, 1H, eAreH), 7.56e7.64 (m, 5H, eAreH), 7.76
(d, 1H, J ¼ 16.1 Hz), 7.86e7.88 (m, 1H, eAreH), 8.05 (d, 1H,
J ¼ 15.3 Hz, eAreH), 8.33 (d, 1H, J ¼ 15.3 Hz, eAreH), 8.64 (d, 1H,
J ¼ 15.3 Hz, eAreH), 8.86 (d, 1H, J ¼ 3.6 Hz, eAreH); 13C NMR
(75 MHz, DMSO-d6): 121.0, 121.8, 122.1, 123.4, 123.7, 124.5, 125.3,
125.6, 126.3, 126.4, 126.9, 127.1, 128.7, 128.9, 130.0, 130.8, 132.9,
133.8, 136.0, 139.7, 150.7; MS (EI): m/z 463.27 [Mþ þ Hþ]; C32H22N4.
2.2.1. 3a. 5,6-bis[(E)-2-phenylvinyl]-3-pyridin-2-
yl-1,2,4-triazine (Table 1 entry 1)
Yellow solid; mp 72e74 ꢀC; Rf 0.80 (40% AcOEt/Petroleum
ether); IR (KBr): 1072, 1365, 1484, 1623 cmꢁ1 1H NMR (500 MHz,
;
CDCl3):
d
7.38e7.43 (m, 8H, eAreH), 7.45 (d, 1H, J ¼ 8.4 Hz,
eAreH), 7.50 (s, 1H, eAreH), 7.67e7.70 (m, 3H, eAreH), 7.91e7.94