Efficient synthesis of 3,5,6-trisubstituted-1,2,4-triazines in the Bronsted acidic ionic liquid, 1-n-butylimidazolium tetrafluoroborate ([Hbim]BF4)

Article abstract of DOI:10.1080/00397910601033534

3,5,6-Trisubstituted-1,2,4-triazines were synthesized in a one-pot reaction with acid hydrazide, 1,2-diketone, and ammonium acetate in the Bronsted acidic ionic liquid, 1-n-butyl imidazolium tetrafluoroborate ([Hbim]BF4). Copyright Taylor & Francis Group,

Full text of DOI:10.1080/00397910601033534

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Efficient Synthesis of
3,5,6‐Trisubstituted‐1,2,4‐triazines
in the Brønsted Acidic Ionic Liquid,
1‐n‐Butylimidazolium Tetrafluoroborate
([Hbim]BF4)
T. M. Potewar a , R. J. Lahoti a , Thomas Daniel a & K. V. Srinivasan a
a Division of Organic Chemistry , Technology National Chemical Laboratory ,
Pune, India
Published online: 25 Jul 2007.
To cite this article: T. M. Potewar , R. J. Lahoti , Thomas Daniel & K. V. Srinivasan (2007) Efficient
Synthesis of 3,5,6‐Trisubstituted‐1,2,4‐triazines in the Brønsted Acidic Ionic Liquid, 1‐n‐Butylimidazolium
Tetrafluoroborate ([Hbim]BF4), Synthetic Communications: An International Journal for Rapid Communication
of Synthetic Organic Chemistry, 37:2, 261-269, DOI: 10.1080/00397910601033534
To link to this article: http://dx.doi.org/10.1080/00397910601033534
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Synthetic Communicationsw, 37: 261–269, 2007
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910601033534
Efficient Synthesis of 3,5,6-Trisubstituted-
1,2,4-triazines in the Brønsted Acidic Ionic
Liquid, 1-n-Butylimidazolium
Tetrafluoroborate ([Hbim]BF4)
T. M. Potewar, R. J. Lahoti, Thomas Daniel, and
K. V. Srinivasan
Division of Organic Chemistry, Technology National Chemical
Laboratory, Pune, India
Abstract: 3,5,6-Trisubstituted-1,2,4-triazines were synthesized in a one-pot reaction
with acid hydrazide, 1,2-diketone, and ammonium acetate in the Brønsted acidic
ionic liquid, 1-n-butyl imidazolium tetrafluoroborate ([Hbim]BF4).
Keywords: acid hydrazides, aliphatic and aromatic 1,2-diketones, ammonium acetate,
ionic liquid (IL), 3,5,6-trisubstituted 1,2,4-triazines
INTRODUCTION
Naturally occurring antibiotics such as fervenulin, toxoflavin, and reurhycin
contain the 1,2,4-triazine moiety.[1] During the past few years, several
methods for the synthesis of 1,2,4-triazines have been reported.[2–5] One of
these attempts involved the condensation of substituted 1,2-diketone with
acid hydrazide in acetic acid to yield trisubstituted 1,2,4-triazine (as-triazine).[6]
Room-temperature ionic liquids (ILs) are becoming solvents of choice
because of their low vapor pressure, nonvolatility, large liquid range, and
thermal stability.[7–11] Herein we report the synthesis of 3,5,6-trisubstituted-
1,2,4-triazines 3a–s by a one-pot condensation reaction of acid hydrazides
Received in India June 22, 2006
Address correspondence to K. V. Srinivasan, Division of Organic Chemistry, Tech-
nology National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
E-mail: kv.srinivasan@ncl.res.in
261

262
T. M. Potewar et al.
Scheme 1. Synthesis of 3,5,6-trisbustituted-1,2,4-triazines.
1, 1,2-diketones 2 (aromatic as well as aliphatic), and ammonium acetate in
the Brønsted acidic IL [Hbim]BF4 (Scheme 1).
RESULTS AND DISCUSSION
ILs based on 1-n-butylimidazolium salts [Hbim]X with varying basicity of
anions such as BF4, Br, Cl, and ClO4 were prepared and used for the typical
reaction of benzoic hydrazide, benzil, and ammonium acetate. The reactions
in different ILs were carried out at the optimized temperature of 1008C
until completion of the reaction; the resulting 3,5,6-triphenyl-1,2,4-triazine
was isolated and structurally analyzed. The results are recorded in Table 1.
The best results were obtained using [Hbim]BF4 as a reaction medium in
terms of time for complete conversion and yield. It is important to note
that the IL [Hbim]BF4 also exhibited maximum Brønsted acidity in terms
of –NH proton chemical shift as well as maximum polarity on the ET (30)
scale (Table 1).
Consequently all further studies were carried out using [Hbim]BF4 as a
reaction medium as well as promoter for the synthesis of diverse array of
3,5,6-trisubstituted-1,2,4-triazines. The results are recorded in Tables 2 and
3. The process tolerates both electron-donating and electron-withdrawing sub-
stituents in acid hydrazides. The methodology is equally efficient for the
synthesis of 3-aryl-5,6-dialkyl-1,2,4-triazines from aliphatic 1,2-diketones.
Table 1. Synthesis of 3,5,6-triphenyl-1,2,4-triazine 3a in [Hbim]X
-NH proton d
ppm
ET (30)
kcal mol21
a
ILs
pKa
)
Time (min)b Yield (%)c
[Hbim]ClO4 211
11.83
12.17
12.22
14.59
63.82
73.68
73.59
74.35
360
100
70
67
77
78
84
[Hbim]Br
[Hbim]Cl
[Hbim]BF4
29
27
0.5
30
aThe pKa values of the parent acid of the anions.
bTime required for complete conversion of the starting material.
cIsolated yield after column chromatography.

3,5,6-Trisubstituted-1,2,4-triazines
263
Table 2. Synthesis of 3,5,6-triaryl-1,2,4-triazine from aromatic 1,2-diketone
Acid
hydrazide
1,2-diketone
2
1
Triazines Time Yieldaref.
Entry
R
R0
R00
3
(min)
(%)
1
2
C6H5
(p-NH2)C6H4 C6H5
(p-Me)C6H4 C6H5
(m-OMe)C6H4 C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
3a
3b
3c
3d
3e
3f
30
30
35
20
45
50
20
20
15
45
55
60
25
20
84[3]
91[2]
82[3]
77[2]
90[2]
83
3
4
5
(p-Cl)C6H4
(o-Cl)C6H4
C6H5
C6H5
C6H5
(p-Me)C6H4
6
7
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
3g
3h
3i
88
90
8
(p-NH2)C6H4 (p-Me)C6H4
(p-Me)C6H4 (p-Me)C6H4
(m-OMe)C6H4 (p-Me)C6H4
9
85
80
10
11
12
13
14
3j
(p-Cl)C6H4
(o-Cl)C6H4
C6H5
(p-Me)C6H4
(p-Me)C6H4
3k
3l
91
81
(p-OMe)C6H4 (p-OMe)C6H4
(p-OMe)C6H4 (p-OMe)C6H4
3m
3n
86
78
(p-Me)C6H4
aIsolated yields after column chromatography.
However, two regioisomers were obtained when the reaction was carried out
using asymmetrical aliphatic 1,2-diketone as shown in Scheme 2. These
regioisomers were seperated by flash-column chromatography and character-
ized by 1H NMR spectroscopy. In the case of regioisomer 3o, the methyl group
at the C-5 position appeared as a singlet at 2.61 d ppm whereas for 3o0 the
methyl group appeared as singlet at 2.71 d ppm.
1
All the compounds were well characterized by melting point, IR, H
NMR, 13C NMR spectral, and elemental analyses. For the known
compounds, the values were in agreement with those reported in literature.
In conclusion, we have developed a one-pot method for the synthesis of a
diverse array of 3,5,6-trisubstituted-1,2,4-triazines in excellent isolated yields
in short reaction times using the Brønsted acidic ionic liquid [Hbim]BF4 as a
reaction medium as well as promoter for the reaction. The methodology
was general for the synthesis of 3,5,6-triaryl-1,2,4-triazines as well as
3-aryl-5,6-dialkyl-1,2,4-triazines derived from aromatic 1,2-diketone and
aliphatic 1,2-diketones respectively.
EXPERIMENTAL
1H NMR spectra were recorded at 200 MHz on a Bruker AV-200 spectrometer,
and chemical shifts (d) are recorded in parts per million (ppm) relative to

Table 3. Synthesis of 3-aryl-5,6-dialkyl-1,2,4-triazines from aliphatic 1,2-diketones
Aliphatic
1,2-diketone
(2)
Time
(min)
Entry
1
Acid hydrazide (1)
Product (3)
Yielda (%)
35
25
40
73 (3o/3o0: 40:60)
2
3
61
56 (3q/3q0: 58:42)
4
5
10
15
52
68
aIsolated yield after column chromatography.

3,5,6-Trisubstituted-1,2,4-triazines
265
Scheme 2. Reaction for asymmetrical 1,2-diketone.
internal tetramethylsilane (d ¼ 0.00). 13C NMR spectra were recorded at
50 MHz, and chemical shifts (d) are recorded in ppm relative to CDCl3
(d ¼ 77.0). Infrared spectra were recorded with ATI MATT-SON RS-1 FTIR
spectrometer using KBr pellets. Polarity of ILs was recorded on Lambda EZ
201, using Reichardt’s dye. Elemental analyses were obtained using a flash
EA 1112 Thermofinnigan instrument. Melting points were recorded in open
capillaries on a Buchi melting-point B-540 apparatus. All solvents and
chemicals were of research grade and were used as obtained from Merck and
Lancaster. The ILs were prepared as per the procedure reported by us earlier.[12]
General Procedure for the Synthesis of 3,5,6-Trisubstituted-1,2,4-
triazines
A mixture of acid hydrazide 1 (1 mmol), 1,2-diketone 2, (1 mmol), and
ammonium acetate (10 equiv.) in 1-n-butylimidazolium tetrafluoroborate,
[Hbim]BF4 (2 ml), was heated at 1008C with stirring for the appropriate
time as mentioned in Tables 2 and 3. The reaction mixture was diluted with
water (25 ml); 3,5,6-trisubstituted-1,2,4-triazines 3 were filtered, washed with
water, and dried. The crude products were subjected to further purification by
chromatography through a column of silica gel to afford pure products.
Data
3-(o-Chlorophenyl)-5,6-diphenyl-1,2,4-triazine (3f). Yellow amorphous solid
(83%), Rf 0.47 (ethyl acetate/petroleum ether: 15:85); mp 1698C; IR (cm21
)
1
3019, 2935, 2852, 1596, 1596, 1446, 759; H NMR (CDCl3, 200 MHz) d
8.08–8.04 (dd, J ¼ 5.92, 3.53 Hz, 1H), 7.69–7.30 (m, 13H); 13C NMR
(CDCl3, 50 MHz) d 162.3, 155.1, 154.9, 135.3, 135.1, 134.5, 133.3, 132.0,
131.1, 130.8, 130.7, 129.8, 129.6, 129.4, 128.5, 128.4, 126.8; C21H14ClN3
(343.5) calcd. C, 73.36;H, 4.10; Cl, 10.31; N, 12.22; found C, 73.10;H,
4.25; Cl, 10.37; N, 12.29.
3-Phenyl-5,6-di(p-tolyl)-1,2,4-triazine (3g). Yellow amorphous solid (88%),
Rf 0.42 (ethyl acetate/petroleum ether: 10:90); mp 1688C; IR (cm21) 3018,
2924, 1609, 1596, 1493, 1443, 822, 756; H NMR (CDCl3, 200 MHz) d
1

266
T. M. Potewar et al.
8.67–8.65 (dd, J ¼ 6.29, 3.15 Hz, 2H), 7.61–7.52 (m, 7H), 7.21–7.16 (dd,
4H), 2.39 (s, 6H); 13C NMR (CDCl3, 50 MHz) d 160.7, 155.2, 155.1, 140.9,
139.4, 134.8, 133.0, 132.7, 131.2, 129.6, 129.1, 129.0, 128.6, 128.1, 21.2;
C23H19N3 (337) calcd. C, 81.87; H, 5.68; N, 12.45; found C, 81.75; H,
5.78; N, 12.39.
3-(p-Aminophenyl)-5,6-di(p-tolyl)-1,2,4-triazine (3h). Dark yellow solid
(90%), Rf 0.33 (ethyl acetate/petroleum ether: 30:70); mp 2018C; IR
(cm21) 3487, 3400, 3017, 2923, 2862, 1606, 1577, 1519, 1497, 821, 756;
1H NMR (CDCl3, 200 MHz) d 8.47–8.43 (d, J ¼ 8.7 Hz, 2H), 7.57–7.47
(m, 4H), 7.18–7.11 (dd, J ¼ 7.86, 4.52 Hz, 4H), 6.77–6.73 (d, J ¼ 8.7 Hz,
2H), 3.93 (brs, 2H), 2.36–2.35 (dd, 6H); 13C NMR (CDCl3, 50 MHz) d
ppm 161.0, 154.9, 154.2, 149.7, 140.6, 133.4, 133.1, 129.8, 129.1, 114.6,
21.3, 21.2; C23H20N4 (352) calcd. C, 78.38; H, 5.72; N, 15.90; found C,
78.50; H, 5.51; N, 16.01.
3,5,6-Tri(p-tolyl)-1,2,4-triazine (3i). Yellow amorphous solid (85%), Rf 0.42
(ethyl acetate/petroleum ether: 10:90); mp 1658C; IR (cm21) 3018, 2923,
d 8.56–8.53
1611, 1495, 821, 758; 1H NMR (CDCl3, 200 MHz)
(d, J ¼ 8.10 Hz, 2H), 7.60–7.51 (dd, J ¼ 8.05 Hz, 4H), 7.36–7.33
(d, J ¼ 8.10 Hz, 2H), 7.19–7.15 (dd, J ¼ 7.31, 5.73 Hz, 4H), 2.45 (s, 3H), 2.38
(s, 6H); 13C NMR (CDCl3, 50 MHz) d 160.8, 155.0, 154.9, 141.5, 140.8, 139.3,
133.0, 132.7, 132.0, 129.6, 129.3, 129.1, 129.0, 128.0, 21.4, 21.3; C24H21N3
(351) calcd. C, 82.02; H, 6.02; N, 11.96; found C, 82.22; H, 5.87; N, 12.02.
3-(m-Methoxyphenyl)-5,6-di(p-tolyl)-1,2,4-triazine (3j). Yellow solid (80%),
Rf 0.44 (ethyl acetate/petroleum ether: 15:85); mp 998C; IR (cm21) 3015,
2923, 2837, 1609, 1585, 1496, 1453, 1215, 821, 758; H NMR (CDCl3,
1
200 MHz) d 8.26–8.23 (d, J ¼ 8.43 Hz, 2H), 7.61–7.43 (m, 5H), 7.21–
7.09 (m, 5H), 3.93 (s, 3H), 2.39 (s, 6H); 13C NMR (CDCl3, 50 MHz) d
160.6, 159.9, 155.2, 155.1, 141.0, 139.5, 136.2, 133.0, 132.7, 129.7, 129.2,
129.1, 120.7, 117.7, 112.6, 55.3, 21.3; C24H11N3O (367) calcd. C, 78.45; H,
5.76; N, 11.44; found C, 78.59; H, 5.43; N, 11.69.
3-(p-Chlorophenyl)-5,6-di(p-tolyl)-1,2,4-triazine (3k). Yellow solid (91%),
Rf 0.52 (ethyl acetate/petroleum ether: 10:90); mp 1718C; IR (cm21) 3018,
2922, 2857, 1609, 1596, 1575, 1487, 820, 758; H NMR (CDCl3, 200 MHz)
1
d 8.62–8.58 (dd, J ¼ 8.60 Hz, 2H), 7.61–7.49 (m, 6H), 7.22–7.16 (dd,
J ¼ 8.0, 3.91 Hz, 4H), 2.40 (s, 6H); 13C NMR (CDCl3, 50 MHz) d 160.0,
155.4, 155.2, 141.1, 139.6, 137.5, 133.4, 132.9, 129.6, 129.4, 129.2, 129.1,
128.9, 21.3, 21.2; C23H18ClN3 (371.5) calcd. C, 74.29; H, 4.88; Cl, 9.53; N,
11.30; found C, 74.11; H, 4.98; Cl, 9.83; N, 11.09.
3-(o-Chlorophenyl)-5,6-di(p-tolyl)-1,2,4-triazine (3l). Yellow solid (81%), Rf
0.33 (ethyl acetate/petroleum ether: 10:90); mp 1508C; IR (cm21) 3019,

3,5,6-Trisubstituted-1,2,4-triazines
267
2925, 2862, 1610, 1496, 1434, 822, 763; 1H NMR (CDCl3, 200 MHz) d 8.07–
8.02 (dd, J ¼ 5.77, 3.80 Hz, 1H), 7.61–7.56 (m, 5H), 7.47–7.42 (m, 2H),
7.23–7.14 (m, 4H), 2.41–2.37 (d, 6H); 13C NMR (CDCl3, 50 MHz) d
162.1, 154.9, 154.7, 141.1, 139.7, 134.8, 133.4, 132.7, 132.5, 132.0, 130.9,
130.7, 129.8, 129.3, 129.2, 129.1, 126.7, 21.2; C23H18ClN3 (371.5) calcd.
C, 74.29; H, 4.88; Cl, 9.53; N, 11.30; found C, 74.35; H, 4.81; Cl, 9.66; N,
11.19.
3-Phenyl-5,6-di(p-methoxyphenyl)-1,2,4-triazine (3m). Yellow amorphous
solid (86%), Rf 0.40 (ethyl acetate/petroleum ether: 20:80); mp 1658C; IR
(cm21) 3018, 2967, 2840, 1607, 1518, 1489, 1465, 1216, 835, 758; 1H
NMR (CDCl3, 200 MHz) d 8.67–8.62 (m, 2H) 7.73–7.53 (m, 7H), 6.95–
6.85 (m, 4H), 3.86–3.83 (dd, 6H); 13C NMR (CDCl3, 50 MHz) d 161.6,
160.5, 160.4, 154.6, 154.4, 134.9, 131.9, 131.1, 130.6, 128.6, 128.0, 113.9,
113.8, 55.2; C23H19N3O2 (369) calcd. C, 74.78; H, 5.18; N, 11.37; found C,
74.52; H, 5.37; N, 11.51.
3-(p-Tolyl)-5,6-di(p-methoxyphenyl)-1,2,4-triazine (3n). Yellow crystalline
solid (78%), Rf 0.40 (ethyl acetate/petroleum ether: 20:80); mp 1498C; IR
1
(cm21) 3006, 2935, 2838, 1607, 1577, 1518, 1488, 1460, 1215, 833, 755; H
NMR (CDCl3, 50 MHz) d 8.55–8.51 (d, J ¼ 8.17 Hz, 2H), 7.71–7.57 (m, 4H),
7.36–7.32 (d, J ¼ 8.17 Hz, 2H), 6.93–6.85 (m, 4H), 3.84–3.83 (d, 6H), 2.45
(s, 3H); 13C NMR (CDCl3, 200 MHz) d 161.4, 160.4, 154.2, 141.4, 132.1,
131.3, 130.5, 129.3, 128.0, 127.9, 113.8, 113.7, 55.0, 21.4; C24H21N3O2 (383)
calcd. C, 75.18; H, 5.52; N, 10.98; found C, 74.98; H, 5.67; N, 11.09.
3-Phenyl-5-methyl-6-ethyl-1,2,4-triazine (3o) and 3-Phenyl-5-ethyl-6-
methyl-1,2,4-triazine (3o0). 3o: white needle crystals, Rf 0.48 (ethyl acetate/
petroleum ether: 20:80); mp 1038C; IR (cm21) 2928, 2845, 1611, 1542,
1
1487, 742; H NMR (CDCl3, 200 MHz) d 8.54–8.49 (m, 2H), 7.53–7.49
(m, 3H), 3.08–2.79 (q, J ¼ 7.32 Hz, 2H), 2.61 (s, 3H), 1.47–1.40
(t, J ¼ 7.32 Hz, 3H); 13C NMR (CDCl3, 50 MHz) d 161.5, 159.2, 158.1,
135.0, 131.0, 130.9, 128.6, 127.8, 127.7, 25.9, 21.2, 11.6; C12H13N3 (199)
calcd. C, 72.33; H, 6.58; N, 21.09; found C, 72.66; H, 6.47; N, 20.91. 3o0:
faint orange crystalline solid, Rf 0.38 (ethyl acetate/petroleum ether:
1
20:80); mp 1228C; IR (cm21) 2947, 2855, 1610, 1598, 1478, 748; H NMR
(CDCl3, 200 MHz) d 8.56–8.51 (m, 2H), 7.53–7.49 (m, 3H), 2.91–2.80
(q, J ¼ 7.41 Hz, 2H), 2.71 (s, 3H), 1.44–1.37 (t, J ¼7.41 Hz, 3H); 13C
NMR (CDCl3, 50 MHz) d 161.9, 161.7, 155.1, 135.1, 130.8, 128.4, 127.7,
27.3, 18.8, 10.1; C12H13N3 (199) calcd. C, 72.33; H, 6.58; N, 21.09; found
C, 72.57; H, 6.33; N, 21.10.
3-Phenyl-5,6,7,8-tetrahydro-benzo[1,2,4]triazine (3p). Orange solid (61%), Rf
0.61 (ethyl acetate/petroleum ether: 20:80); mp 858C; IR (cm21) 3016, 2950,
2870, 1600, 1519, 1452, 1419, 1215, 756; H NMR (CDCl3, 200 MHz) d
1

268
T. M. Potewar et al.
8.51–8.44 (m, 2H), 7.54–7.49 (m, 3H), 3.18–3.14 (d, J ¼ 6.54 Hz, 2H),
3.02–2.99 (d, J ¼ 6.27 Hz, 2H), 2.01–1.94 (m, 4H); 13C NMR (CDCl3,
50 MHz) d 161.6, 158.9, 135.3, 130.9, 128.5, 127.8, 26.7, 25.4, 12.05,
10.74; C13H13N3 (211) calcd. C, 73.97; H, 6.20; N, 19.89; found C, 74.05;
H, 6.04; N, 19.96.
3-(p-Tolyl)-5-ethyl-6-methyl-1,2,4-triazine (3q) and 3-(p-Tolyl)-5-methyl-6-
ethyl-1,2,4-triazine (3q0). 3q: orange crystalline solid, Rf 0.38 (ethyl acetate/
petroleum ether: 20:80); mp 788C; IR (cm21) 2943, 2839, 1609, 1541, 1478,
1
740; H NMR (CDCl3, 200 MHz) d 8.35–8.31 (d, 2H), 7.24–7.20 (d, 2H),
2.80–2.69 (q, J ¼ 7.38 Hz, 2H), 2.60 (s, 3H), 2.34 (s, 3H), 1.34–1.26
(t, J ¼ 7.38 Hz, 3H); 13C NMR (CDCl3, 50 MHz) d 161.9, 161.8, 154.8,
141.2, 132.6, 129.3, 127.8, 27.4, 21.3, 18.8, 10.2; C13H15N3 (213) calcd. C,
73.21; H, 7.09; N, 19.70; found C, 73.33; H, 6.98; N, 19.76. 3q0: faint
yellow crystalline solid, Rf 0.44 (ethyl acetate/petroleum ether: 20:80); mp
1
1028C; IR (cm21) 2953, 2848, 1608, 1541, 1459, 748; H NMR (CDCl3,
200 MHz) d 8.46–8.29 (d, J ¼ 7.92 Hz, 2H), 7.36–7.19 (d, J ¼ 7.92 Hz,
2H), 2.96–2.84 (q, J ¼ 7.47 Hz, 2H), 2.48 (s, 3H), 2.33 (s, 3H), 1.36–1.29
(t, J ¼ 7.47 Hz, 3H); 13C NMR (CDCl3, 50 MHz) d 161.6, 158.9, 158.0,
141.3, 132.3, 129.3, 127.7, 25.9, 21.4, 21.3, 11.7; C13H15N3 (213) calcd. C,
73.21; H, 7.09; N, 19.70; found C, 73.09; H, 7.16; N, 19.77.
3-(p-Tolyl)-5,6,7,8-tetrahydro-benzo[1,2,4] triazine (3r). Faint yellow solid
(52%), Rf 0.48 (ethyl acetate/petroleum ether: 30:70); mp 1008C; IR
1
(cm21) 3018, 2949, 2888, 1613, 1532, 1517, 1453, 1215, 757; H NMR
(CDCl3, 200 MHz)
d
8.32–8.28 (d, J ¼ 7.84 Hz, 2H), 7.25–7.21
(d, J ¼ 7.84 Hz, 2H), 3.09–2.91 (dd, 4H), 2.35 (s, 3H), 1.91–1.90 (d, 4H);
13C NMR (CDCl3, 50 MHz) d 161.6, 158.8, 156.2, 141.1, 132.4, 129.3,
127.7, 31.5, 29.1, 22.0, 21.7, 21.4; C14H15N3 (225) calcd. C, 74.64; H, 6.71;
N, 18.65; found C, 74.55 H, 6.81; N, 18.59.
3-(p-Tolyl)-5,6-diethyl-1,2,4-triazine (3s). Faint orange crystalline solid
(68%), Rf 0.42 (ethyl acetate/petroleum ether: 15:85); mp 888C; IR (cm21
)
1
2978, 2938, 2878, 1612, 1534, 1515, 1460, 1216, 757; H NMR (CDCl3,
200 MHz) d 8.45–8.41 (d, J ¼ 8.21 Hz, 2H), 7.32–7.28 (d, J ¼ 8.21 Hz,
2H), 3.05–2.80 (m, 4H), 2.42 (s, 3H), 1.46–1.36 (m, 6H); 13C NMR
(CDCl3, 50 MHz) d 161.2, 158.3, 140.9, 132.3, 129.0, 127.5, 26.5, 25.1,
21.2, 11.7, 10.4; C14H17N3 (227) calcd. C, 73.98; H, 7.54; N, 18.49; found
C, 74.11; H, 7.43; N, 18.54.
ACKNOWLEDGMENTS
T. M. P. thanks the Council of Scientific and Industrial Research (CSIR), New
Delhi, for the award of Research Fellowships. The authors also acknowledge

3,5,6-Trisubstituted-1,2,4-triazines
269
financial assistance from the Department of Science and Technology (DST),
New Delhi, Project No. SR/S5/OC-23/2002.
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