An efficient and facile synthesis of polydentate ligand: Pyridylpyrimidine-2-amine under solvent-free conditions

Article abstract of DOI:10.1007/s11164-012-0526-9

An efficient and facile synthesis of polydentate ligand pyridylpyrimidine-2-amine via a one-pot reaction of different aromatic aldehydes, 2-acetylpyridine and guanidine carbonate, in the presence of NaOH under solvent-free conditions, is reported. These c

Full text of DOI:10.1007/s11164-012-0526-9

Res Chem Intermed (2012) 38:2065–2073
DOI 10.1007/s11164-012-0526-9
An efficient and facile synthesis of polydentate ligand:
pyridylpyrimidine-2-amine under solvent-free
conditions
•
Shimin Tao Sheng Xia Liangce Rong
•
•
•
Changsheng Cao Shujiang Tu
Received: 19 January 2012 / Accepted: 29 February 2012 / Published online: 15 March 2012
Ó Springer Science+Business Media B.V. 2012
Abstract An efficient and facile synthesis of polydentate ligand pyridylpyr-
imidine-2-amine via a one-pot reaction of different aromatic aldehydes, 2-acetyl-
pyridine and guanidine carbonate, in the presence of NaOH under solvent-free
conditions, is reported. These compounds have four N-donors and they are classic
polydentate ligands of many metal ions. Due to employing a one-pot, multicom-
ponent reaction, this method offers several advantages including easy experimental
work-up procedure, and lower cost, short reaction time, and especially high yields
of products. This paper therefore develops a practical and convenient process for the
synthesis of these ligands.
Keywords Polydentate ligand ꢀ Pyridylpyrimidine-2-amine ꢀ
Multicomponent reaction ꢀ Solvent-free synthesis ꢀ Green chemistry
Introduction
The rational design and construction of novel metal–organic complexes (coordi-
nation compounds) has been the subject of a great many studies in recent years, not
only due to their structural and topological novelty [1–3] but also for their potential
applications as functional materials such as catalysts, molecular recognition,
separation, and nonlinear optics [4–7]. The structure of metal–organic complexes is
greatly influenced by many factors such as the coordination geometry of metal ions,
the structure of organic ligands, the solvent system, the counteranion, and the ratio
of ligands to metal ions [8–15]. Among these factors, synthesis of new organic
S. Tao ꢀ S. Xia ꢀ L. Rong (&) ꢀ C. Cao ꢀ S. Tu
Jiangsu Key Laboratory of Green Synthetic Chemistry For Functional Materials,
College of Chemistry and Chemical Engineering, Xuzhou Normal University, Xuzhou,
Jiangsu 221116, People’s Republic of China
e-mail: lcrong2005@yahoo.com
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S. Tao et al.
ligands is one of the most important topics. From the stability of the coordination
compounds, polydentate ligand is much better than monodentate ligand. In this
regard, a large number of polydentate ligands were designed and utilized. Among
them, there is an increasing interest in the N,N’-chelating ligands, especially the
N,N’-chelating oligopyridine ligands[16–19], for instance 2,20-bipyridine and its
derivatives [20–22].
Green chemistry has become a powerful strategy in organic chemistry in the last
decade [23–25], and current areas of interest are the generation of complex
molecular systems via multicomponent reactions under solvent-free conditions [26–
28]. The avoidance solvents in chemical processes, or the replacement of hazardous
solvents with more benign solvents, have become major concerns in academia and
industry, and the need for green reactions is now globally accepted. Solvent-free
multicomponent syntheses are particularly attractive, because they incorporate
many green chemistry principles.
Pyridylpyrimidine, as N,N’-chelating ligands, has four N-donors and can act as a
neutral mono- or bidentate ligand and an anionic tridentate ligand. This compound
has tunable coordination modes and supramolecular interactions because it is the
multidentate ligand and includes hydrogen-bonding donor and acceptors (aromatic
N atoms) (Fig. 1), so chelate complexes or polymers can be obtained from
pyridylpyrimidines. Thus, this type of N-heterocyclic ligand is a good choice in
constructing metal–organic frameworks with interesting structures and properties.
As we have synthesized some organic compounds under solvent-free conditions [29–
31], we report here a simple and efficient method for the synthesis of N,N’-chelating
polydentate ligands, i.e., pyridylpyrimidine-2-amine under solvent-free conditions.
Results and discussion
We have carefully investigated synthetic methods that have been reported of these
compounds. We found that only a few papers have reported preparing similar
compounds. For example, Rajendra [32] used condensation products of 2-acetyl-
pyridine with different aldehydes, then reacted them with guanidine hydrochloride
to give several 2-amino-4-(substituted phenyl/anthryl)-6-(20-pyridyl)pyrimidines
under EtOH condition, which were in fact two step reactions. Raymond [33]
has also reported the synthesis of some substituted pyrimidines by condensing
the b-diketone or b-keto ester with guanidine carbonate. In the reported methods,
organic solvents were necessary. As a solvent-free condition, organic synthesis is a
R
R
N
R
N
R
N
M
M
N
N
N
N
N
NH-
M
NH2
NH2
NH2
N
M
N
N
M
N
M
M
Fig. 1 The coordination modes of pyridylpyrimidine-2-amine ligands
123

Synthesis of polydentate ligand
2067
powerful tool of current organic reactions, and we want to try to synthesize these
compounds under solvent-free conditions.
2-Fluorobenzaldehyde 1a, 2-acetylpyridine 2, and guanidine carbonate 3 were
chosen as the starting material for the model reaction, and three reagents were
reacted under solvent-free conditions using different catalysts. In our research, we
found that, when an organic base (such as Et3N, C5H11N, DBU, etc.) and lewis acid
(such as ZnCl2, FeCl3, MgCl2, SnCl2, etc.) were used as catalysts, the reaction could
did not occur. When we used an inorganic base, K2CO3, Na2CO3, and Cs2CO3, the
product could be generated, but with very low yield. When a strong base such as
NaOH was used, the reaction could be carried out smoothly with high yield. We also
found that higher loading of the NaOH did not improve the yields of the reaction,
and, conversely, the yield was depressed, perhaps because large amounts of NaOH
could turn the reagents into solids very quickly, and that hindered the reaction from
continuing. Another strong base, KOH, is also an efficient catalyst of this reaction;
however, compared with NaOH, the yield of the product is not obviously improved.
Taking into account all the conditions, we chose NaOH as the ideal catalyst to
accomplish these syntheses. The optimized reaction conditions are summarized in
Table 1.
Under this optimized condition, the different aromatic aldehydes were allowed to
undergo a one-pot reaction with 2-acetylpyridine and guanidine carbonate, affording
a series of 4-aryl-6-(pyridin-2-yl) pyrimidin-2-amine with high yields in only about
45 min. (Scheme 1). The results of the reactions are listed in Table 2. As shown in
Table 2, 14 compounds have been synthesized. No matter whether it was electron-
withdrawing (such as F, Cl, and Br) or electron-donating substitute groups (CH3-
and CH3O-) on aromatic aldehydes, the products could be obtained with ideal
results.
Table 1 Synthesis of 4a under
solvent-free conditions in the
presence of different catalysts
Entry
Amount (mmol)
Catalyst
Et3N
Yielda/%
1
0.2–0.4
0.2–0.4
0.2–0.4
0.2–0.4
0.2–0.4
0.2–0.4
0.2–0.4
0.4
0
2
C5H11N
0
3
DBU
0
4
ZnCl2
FeCl3
0
5
0
6
MgCl2
SnCl2
0
7
0
8
Na2CO3
K2CO3
Cs2CO3
NaOH
NaOH
NaOH
KOH
23
26
21
85
90
95
81
91
Reagents and conditions:
2-Fluorobenzaldehyde 1a
(1 mmol), 2-acetylpyridine 2
(1 mmol), and guanidine
carbonate 3 (1.5 mmol), reaction 12
temperature 70 °C
Bold indicates the best yield,
9
0.4
10
11
0.4
0.4
0.3
13
0.2
14
0.4
for NaOH
a
Isolated yields
15
0.2
KOH
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S. Tao et al.
Ar
NH
NH2
Solvent-free
N
H2CO3
+
+
ArCHO
CH3
H2N
N
2
N
NH2
O
N
1
2
3
4
Scheme 1 Synthesis of 4-aryl-6-(pyridin-2-yl)pyrimidin-2-amine
Table 2 Synthetic results
of compounds 4
Entry
Ar
Product
Yields (%)
1
2-FC6H4
4a
4b
4c
4d
4e
4f
95
91
94
90
92
91
89
92
90
93
94
95
91
96
2
3-FC6H4
3
4-FC6H4
4
4-ClC6H4
5
2,4-Cl2C6H3
3,4-Cl2C6H3
2-BrC6H4
6
7
4g
4h
4i
8
4-BrC6H4
9
4-CH3C6H4
3,4-(CH3)2C6H3
3-CH3OC6H4
4-CH3OC6H4
3,4-(CH3O)2C6H3
3,4,5-(CH3O)3C6H2
10
11
12
13
14
4j
4k
4l
4m
4n
All the products were characterized by IR, 1H-NMR, 13C-NMR, and HRMS. For
1
example, in H-NMR, 4i shows a singlet at delta 2.36 due to the CH3 protons and
a singlet at delta 5.24 due to the NH2 protons, as well as doublets at delta 7.23
(J = 8.0 Hz), 8.00 (J = 8.0 Hz), 8.32 (J = 7.6 Hz), 8.68 (J = 8.8 Hz), and a
multiplet at delta 7.30–7.33, a singlet at delta 8.06, and a triplet at delta 7.77
(J = 8.0 Hz) due to the nine aryl protons. In 13C-NMR, the chemical shifts of 16
carbon atoms show at 21.43, 104.03, 121.56, 124.90, 127.16, 129.39, 134.64,
136.91, 140.81, 149.33, 154.78, 163.50, 164.50, and 166.56, respectively. In the
HRMS spectrum, the calculated m/z for C16H14N4 [M ? Na]? is 285.1116, and we
found m/z to be 285.1105.
Conclusions
In conclusion, we have expanded an easy and highly efficient one-pot reaction
for the synthesis of 4-aryl-6-(pyridin-2-yl)pyrimidin-2-amine via the reaction of
different aromatic aldehydes, 2-acetylpyridine and guanidine carbonate, under
solvent-free conditions with high yields. These compounds have four N-donors and
they are classic polydentate ligands of many metal ions. Due to employing a one-pot
multicomponent reaction, this method offers several advantages, including easy
123

Synthesis of polydentate ligand
2069
experimental work-up procedure, procedure, and lower cost, short reaction time,
and especially high yields of products. This paper develops a practical and
convenient process for the synthesis of these ligands.
Experimental
Melting points were determined on XT-5 microscopic melting-point apparatus and
were uncorrected. IR spectra were recorded on a FT Bruker Tensor 27 spectrometer.
1H NMR spectra were obtained from solution in CDCl3 with Me4Si as internal
standard using a Bruker-400 or Bruker-300 spectrometer. HRMS spectra were
obtained with a Bruker microTOF-Q 134 instrument.
General procedure for the synthesis of 4-aryl-6-(pyridin-2-yl)pyrimidin-2-amine
derivatives
The mixture of aromatic aldehydes 1 (1 mmol), 2-acetylpyridine 2 (1 mmol),
guanidine carbonate 3 (1.5 mmol), and NaOH (0.2 mmol) was put in a reaction
flask at under 70 °C for about 45 min. After completing the reaction, the reaction
mixture was poured into water (0.5 % HCl), and then thoroughly washed with water.
The product was filtered, dried, and recrystallized from 95% ethanol.
4-(2-fluorophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4a)
Melting point 118–119 °C; IR (KBr) v: 3,328, 3,232, 2,360, 2,341, 1,698, 1,684,
1,635, 1,575, 1,558, 1,541, 1,508, 1,490, 1,474, 1,457, 1,425, 1,362, 1,207, 1,203,
1
764, 740, 669 cm-1; H NMR (400 MHz, CDCl3) d: 5.24 (2H, s, NH2), 7.11–7.16
(1H, m, ArH), 7.20–7.24 (1H, m, ArH), 7.31–7.41 (2H, m, ArH), 7.78 (1H, t,
J = 8.0 Hz, ArH), 7.97 (1H, t, J = 8.0 Hz, ArH), 8.09 (1H, d, J = 2.4 Hz, ArH),
8.30-8.32 (1H, m, ArH), 8.68–8.70 (1H, m, ArH); 13C NMR (400 MHz, CDCl3)
d: 108.49 (d, J = 38.4 Hz), 116.38 (d, J = 90.4 Hz), 121.64, 124.39 (d,
J = 14.4 Hz), 124.96, 125.93 (d, J = 43.6 Hz), 130.53 (d, J = 10.4 Hz), 131.65
(d, J = 34.4 Hz), 136.87, 149.51, 154.57, 159.78, 162.29, 162.93 (d, J = 8.8 Hz),
163.32, 164.66.
HRMS m/z calculated for C15H11FN4 [M ? Na]?: 289.0865, found: 289.0879.
4-(3-fluorophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4b)
Melting point 155–156 °C; IR (KBr) v: 3,330, 2,360, 2,341, 1,698, 1,684, 1,647,
1,558, 1,541, 1,522, 1,508, 1,474, 1,458, 669 cm-1; 1H NMR (400 MHz, CDCl3) d:
5.21 (2H, s, NH2), 7.10–7.15 (1H, m, ArH), 7.33–7.37 (1H, m, ArH), 7.39–7.43 (1H,
m, ArH), 7.78–7.85 (2H, m, ArH), 7.87 (1H, d, J = 8.0 Hz, ArH), 8.08 (1H, s,
ArH), 8.34 (1H, d, J = 8.0 Hz, ArH), 8.68 (1H, d, J = 4.4 Hz, ArH); 13C NMR
(400 MHz, CDCl3) d: 104.36, 114.14 (d, J = 91.2 Hz), 117.35 (d, J = 84.8 Hz),
121.58, 122.84 (d, J = 11.2 Hz), 125.11, 130.14 (d, J = 32.0 Hz), 136.96, 139.80
(d, J = 30 Hz), 149.37, 154.44, 161.91, 163.41, 164.36, 165.01.
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HRMS m/z calculated for C15H11FN4 [M ? Na]?: 289.0865, found: 289.0884.
4-(4-fluorophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4c)
Melting point 169–170 °C; IR (KBr) v: 3,343, 2,360, 2,341, 1,716, 1,690, 1,683,
1,652, 1,558, 1,541, 1,508, 1,473, 1,456, 1,361, 1,229, 842, 788, 669 cm-1; 1H NMR
(300 MHz, CDCl3) d: 5.33 (2H, s, NH2), 7.10 (2H, t, J = 6.6 Hz, ArH), 7.31–7.34
(1H, m, ArH), 7.77 (1H, t, J = 5.7 Hz, ArH), 8.05 (1H, s, ArH), 8.09 (2H,
dd, J = 5.2 Hz, J = 6.0 Hz, ArH), 8.33 (1H, d, J = 5.7 Hz, ArH), 8.67 (1H,
d, J = 6.6 Hz, ArH); 13C NMR (300 MHz, CDCl3) d: 103.94, 115.63 (d, J = 86 Hz),
121.56, 125.03, 129.25 (d, J = 34.4 Hz), 133.59 (d, J = 9.3 Hz), 136.94, 149.33,
154.54, 163.29 (d, J = 101.4 Hz), 164.75, 165.51 (d, J = 56.1 Hz).
HRMS m/z calculated for C15H11FN4 [M ? Na]?: 289.0865, found: 289.0882.
4-(4-chlorophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4d)
Melting point 184–185 °C (lit [32], 188 °C); IR (KBr) v: 3,185, 2,360, 2,341, 1,749,
1,717, 1,698, 1,684, 1,647, 1,558, 1,541, 1,508, 1,490, 1,474, 1,457, 1,361, 1,090,
829, 786, 669 cm-1; 1H NMR (400 MHz, CDCl3) d: 5.29 (2H, br, NH2), 7.31–7.41
(3H, m, ArH), 7.74–7.80 (1H, m, ArH), 8.00–8.06 (3H, m, ArH), 8.32 (1H, t,
J = 8.8 Hz, ArH), 8.65–8.68 (1H, m, ArH); 13C NMR (400 MHz, CDCl3) d:
104.00, 121.56, 125.07, 128.51, 128.85, 135.86, 136.61, 136.95, 149.32, 154.45,
163.44, 164.87, 165.24.
HRMS m/z calculated for C15H11ClN4 [M ? H]?: 283.0750, found: 283.0792.
4-(2,4-dichlorophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4e)
Melting point 160–161 °C (lit [32], 180 °C); IR (KBr) v: 3,327, 2,361, 2,341, 1,698,
1
1,684, 1,647, 1,636, 1,558, 1,541, 1,522, 1,508, 1,474, 1,458, 669 cm-1; H NMR
(300 MHz, CDCl3) d: 5.26 (2H, s, NH2), 7.34–7.40 (2H, m, ArH), 7.51 (1H, d,
J = 1.2 Hz, ArH), 7.57 (1H, d, J = 6.2 Hz, ArH), 7.84 (1H, t, J = 6.2 Hz, ArH),
7.97 (1H, s, ArH), 7.37 (1H, d, J = 6.0 Hz, ArH), 8.71 (1H, d, J = 2.7 Hz, ArH);
13C NMR (300 MHz, CDCl3) d: 108.72, 121.67, 125.12, 127.32, 130.05, 131.72,
133.03, 135.61, 136.24, 136.93, 149.51, 154.29, 163.16, 164.39, 165.58.
HRMS m/z calculated for C15H10Cl2N4 [M ? Na]?: 339.0180, found: 339.0198.
4-(3,4-dichlorophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4f)
Melting point 156–157 °C; IR (KBr) v: 3,327, 2,361, 2,341, 1,698, 1,684, 1,647,
1
1,636, 1,558, 1,541, 1,522, 1,508, 1,474, 1,458, 669 cm-1; H NMR (300 MHz,
CDCl3) d: 5.22 (2H, s, NH2), 7.42 (1H, dd, J = 5.1 Hz, J = 6.9 Hz, ArH), 7.59
(1H, d, J = 8.4 Hz, ArH), 7.86 (1H, t, J = 7.8 Hz, ArH), 8.00 (1H, dd, J = 2.1 Hz,
J = 8.4 Hz, ArH), 8.11 (1H, s, ArH), 8.29 (1H, d, J = 1.8 Hz, ArH), 8.40 (1H, d,
J = 7.8 Hz, ArH), 8.74 (1H, d, J = 5.2 Hz, ArH); 13C NMR (300 MHz, CDCl3) d:
103.91, 121.55, 125.17, 126.22, 129.04, 130.03, 130.54, 133.03, 136.98, 139.44,
149.29, 154.83, 162.47, 163.27, 164.39, 165.13.
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HRMS m/z calculated for C15H10Cl2N4 [M ? Na]?: 339.0180, found: 339.0189.
4-(2-bromophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4g)
Melting point 148–149 °C; IR (KBr) v: 3,329, 3,177, 2,360, 2,341, 1,646, 1,575,
1,558, 1,540, 1,475, 1,456, 1,432, 1,349, 1,237, 1,127, 1,073, 993, 846, 790, 773,
1
669, 650 cm-1; H NMR (400 MHz, CDCl3) d: 5.37 (2H, s, NH2), 7.27 (1H, t,
J = 8.0 Hz, ArH), 7.31–7.34 (1H, m, ArH), 7.53 (1H, dd, J = 0.8 Hz, J = 8.0 Hz,
ArH), 7.77 (1H, t, J = 8.0 Hz, ArH), 7.99 (1H, d, J = 8.0 Hz, ArH), 8.04 (1H, s,
ArH), 8.24 (1H, t, J = 1.6 Hz, ArH), 8.32 (1H, d, J = 8.0 Hz, ArH), 8.67 (1H, dd,
J = 0.8 Hz, J = 8.8 Hz, ArH); 13C NMR (400 MHz, CDCl3) d: 104.23, 121.60,
122.95, 125.77, 130.14, 130.24, 133.33, 136.96, 139.51, 149.34, 154.38, 163.45,
164.93, 164.98.
HRMS m/z calculated for C15H11BrN4 [M ? Na]?: 349.0065, found: 349.0016.
4-(4-bromophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4h)
Melting point 193–194 °C; IR (KBr) v: 3,180, 2,361, 2,341, 1,716, 1,698, 1,683,
1
1,647, 1,558, 1,541, 1,522, 1,508, 1,473, 1,459, 669 cm-1; H NMR (300 MHz,
CDCl3) d: 5.25 (2H, s, NH2), 7.32–7.35 (1H, m, ArH), 7.56 (2H, d, J = 6.6 Hz,
ArH), 7.78 (1H, t, J = 6.0 Hz, ArH), 7.97 (2H, d, J = 6.3 Hz, ArH), 8.06 (1H, s,
ArH), 8.33 (1H, d, J = 6.0 Hz, ArH), 8.68 (1H, dd, J = 0.6 Hz, J = 2.7 Hz, ArH);
13C NMR (300 MHz, CDCl3) d: 103.99, 121.58, 125.10, 128.77, 131.83, 136.34,
136.96, 149.34, 154.46, 163.45, 164.93, 165.32.
HRMS m/z calculated for C15H11BrN4 [M ? Na]?: 349.0065, found: 349.0020.
4-(pyridin-2-yl)-6-p-tolylpyrimidin-2-amine (4i)
Melting point 144–145 °C; IR (KBr) v: 3,310, 3,180, 2,361, 2,341, 1,698, 1,684,
1,636, 1,559, 1,541, 1,508, 1,474, 1,457, 1,362, 785, 669 cm-1 1H NMR
;
(400 MHz, DMSO–d6) d: 2.36 (3H, s, CH3), 5.33 (2H, s, NH2) 7.23 (2H, d,
J = 8.0 Hz, ArH), 7.30–7.33 (1H, m, ArH), 7.77 (1H, t, J = 8.0 Hz, ArH), 8.00
(2H, d, J = 8.0 Hz, ArH), 8.06 (1H, s, ArH), 8.32 (1H, d, J = 7.6 Hz, ArH), 8.68
(1H, d, J = 8.8 Hz, ArH); 13C NMR (400 MHz, DMSO-d6) d: 21.43, 104.03,
121.56, 124.90, 127.16, 129.39, 134.64, 136.91, 140.81, 149.33, 154.78, 163.50,
164.50, 166.56.
HRMS m/z calculated for C16H14N4 [M ? Na]?: 285.1116, found: 285.1105.
4-(3,4-dimethylphenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4j)
Melting point 173–174 °C; IR (KBr) v: 3,326, 3,194, 2,360, 2,341, 1,698, 1,645,
1,574, 1,558, 1,540, 1,507, 1,476, 1,456, 1,433, 1,404, 1,350, 1,225, 785, 740,
1
669 cm-1; H NMR (400 MHz, CDCl3) d: 2.27 (3H, s, CH3), 2.30 (3H, s, CH3),
5.28 (2H, s, NH2), 7.19 (1H, d, J = 8.0 Hz, ArH), 7.31–7.34 (1H, m, ArH), 7.77
(1H, t, J = 8.0 Hz, ArH), 7.84 (1H, d, J = 8.0 Hz, ArH), 7.89 (1H, s, ArH), 8.06
(1H, s, ArH), 8.33 (1H, dd, J = 0.8 Hz, J = 8.0 Hz, ArH), 8.69 (1H, dd,
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J = 0.8 Hz, J = 8.0 Hz, ArH); 13C NMR (400 MHz, CDCl3) d: 19.79, 19.85,
104.07, 121.58, 124.73, 124.88, 129.97, 135.00, 136.91, 139.53, 149.32, 154.83,
163.47, 164.39, 166.74.
HRMS m/z calculated for C17H16N4 [M ? Na]?: 299.1273, found: 299.1298.
4-(3-methoxyphenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4k)
Melting point 131–132 °C; IR (KBr) v: 3,336, 3,196, 2,361, 2,341, 1,699, 1,637,
1
1,559, 1,541, 1,508, 1,474, 1,458, 1,361, 1,246, 669 cm-1; H NMR (300 MHz,
CDCl3) d: 3.91 (3H, s, OCH3), 5.22 (2H, s, NH2), 7.04 (1H, d, J = 8.4 Hz, ArH),
7.38–7.43 (2H, m, ArH), 7.72 (2H, d, J = 6.6 Hz, ArH), 7.85 (1H, t, J = 7.8 Hz,
ArH), 8.13 (1H, s, ArH), 8.39 (1H, d, J = 7.8 Hz, ArH), 8.74 (1H, d, J = 4.8 Hz,
ArH); 13C NMR (300 MHz, CDCl3) d: 55.35, 104.50, 111,96, 116.67, 119.69,
121.52, 124.92, 129.59, 136.87, 138.89, 149.30, 154.60, 159.88, 163.32, 166.38.
HRMS m/z calculated for C16H14N4O [M ? Na]?: 301.1066, found: 301.1067.
4-(4-methoxyphenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4l)
Melting point 199–200 °C (lit [32], 142 °C); IR (KBr) v: 3,356, 2,361, 2,341, 1,736,
1,717, 1,698, 1,646, 1,560, 1,541, 1,474, 1,457, 1,435, 1,364, 1,259, 1,178, 1,032,
1
789, 669 cm-1; H NMR (300 MHz, CDCl3) d: 3.87 (3H, s, OCH3), 5.24 (2H, s,
NH2), 6.99 (2H, d, J = 7.2 Hz, ArH), 7.36–7.40 (1H, m, ArH), 7.84 (1H, t,
J = 7.8 Hz, ArH), 8.08 (1H, d, J = 0.9 Hz, ArH), 8.13 (2H, d, J = 7.2 Hz, ArH),
8.37 (1H, d, J = 7.8 Hz, ArH), 8.73 (1H, t, J = 2.7 Hz, ArH); 13C NMR
(300 MHz, CDCl3) d: 55.30, 103.15, 113.90, 121.48, 128.71, 128.78, 129.79,
136.88, 149.26, 154.73, 161.60, 163.33, 164.27, 166.00.
HRMS m/z calculated for C16H14N4O [M ? Na]?: 301.1065, found: 301.1074.
4-(3,4-dimethoxyphenyl)-6-(pyridin-2-yl)pyrimidin-2-amine (4m)
Melting point 192–193 °C (lit [32], 242 °C); IR (KBr) v: 3,340, 3,189, 2,360, 2,341,
1,698, 1,647, 1,559, 1,541, 1,519, 1,474, 1,459, 1,434, 1,354, 1,269, 787, 669 cm-1
;
1H NMR (300 MHz, CDCl3) d: 3.96 (3H, s, OCH3), 4.02 (3H, s, OCH3), 5.26 (2H,
s, NH2), 6.96 (1H, d, J = 8.7 Hz, ArH), 7.38–7.42 (1H, m, ArH), 7.77 (2H, t,
J = 6.0 Hz, ArH), 7.85 (1H, t, J = 7.8 Hz, ArH), 8.10 (1H, s, ArH), 8.39 (1H, d,
J = 7.8 Hz, ArH), 8.74 (1H, d, J = 5.2 Hz, ArH); 13C NMR (300 MHz, CDCl3) d:
55.94, 55.98, 76.58, 77.01, 77.43, 103.64, 109.69, 110.67, 120.48, 121.58, 124.94,
130.08, 136.97, 148.99, 149.29, 151.15, 154.76, 163.34, 164.34, 166.03.
HRMS m/z calculated for C17H16N4O2 [M ? Na]?: 331.1171, found: 331.1175.
4-(pyridin-2-yl)-6-(3,4,5-trimethoxyphenyl)pyrimidin-2-amine (4n)
Melting point 163–164 °C (lit [32], 208 °C); IR (KBr) v: 3,336, 3,198, 2,361, 2,341,
1,717, 1,698, 1,648, 1,560, 1,541, 1,507, 1,457, 1,363, 1,309, 1,221, 1,010, 846,
1
789, 669 cm-1; H NMR (300 MHz, CDCl3) d: 3.88 (3H, s, OCH3), 3.92 (6H, s,
2XOCH3), 5.57 (2H, s, NH2), 7.32–7.37 (3H, m, ArH), 7.78 (1H, t, J = 7.8 Hz,
123

Synthesis of polydentate ligand
2073
ArH), 8.05 (1H, s, ArH), 8.35 (1H, d, J = 7.8 Hz, ArH), 8.70 (1H, d, J = 5.2 Hz,
ArH); 13C NMR (300 MHz, CDCl3) d: 56.15, 60.83, 103.75, 104.27, 121.54,
124.94, 132.84, 136.90, 140.07, 149.16, 153.23, 154.54, 163.39, 164.54, 165.98.
HRMS m/z calculated for C18H18N4O3 [M ? Na]?: 361.1277, found: 361.1284.
Acknowledgments We are grateful to the National Natural Science Foundation of China (NSFC)
(21172188), the Foundation of Xuzhou Normal University (10XLS02) and the Priority Academic
Program Development of Jiangsu Higher Education Institutions for financial support.
References
1. F.C. Liu, Y.F. Zeng, J.R. Li, X.H. Bu, H.J. Zhang, J. Ribas, Inorg. Chem. 44, 7298 (2005)
2. Y.F. Zhou, F.L. Jiang, D.Q. Yuan, B.L. Wu, R.H. Wang, Z.Z. Lin, M.C. Hong, Angew. Chem. Int.
Ed. 43, 5665 (2004)
3. M. Fujita, M. Tominaga, K. Suzuki, M. Kawano, T. Kusukawa, Angew. Chem. Int. Ed. 43, 5621
(2004)
4. M. Fujita, Y.J. Kwon, S. Washizu, K. Ogura, J. Am. Chem. Soc. 116, 1151 (1994)
5. O.R. Evans, W. Lin, Acc. Chem. Res. 35, 511 (2002)
6. K. Kasai, M. Aoyagi, M. Fujita, J. Am. Chem. Soc. 122, 2140 (2000)
7. S. Kitagawa, R. Kitaura, S.I. Noro, Angew. Chem. Int. Ed. 43, 2334 (2004)
8. N.S. Oxtoby, N.R. Champness, Cryst. Eng. Comm 7, 284 (2005)
9. E.Q. Gao, A.L. Cheng, Y.X. Xu, C.H. Yan, M.H. He, Cryst. Growth Des. 5, 1005 (2005)
10. M. Oh, C.L. Stern, C.A. Mirkin, Inorg. Chem. 44, 2647 (2005)
11. M.B. Zaman, K. Udachin, J.A. Ripmeester, Inorg. Chem. 44, 5047 (2005)
12. A.N. Khlobystov, N.R. Champness, M. Schroder, J. Am. Chem. Soc. 125, 6753 (2003)
13. X.C. Huang, J.P. Zhang, Y.Y. Lin, X.M. Chen, Chem. Commun. 2005, 2232 (2005)
14. P. Diaz, J. Benet-Buchholz, R. Vilar, A.J.P. White, Inorg. Chem. 45, 1617 (2006)
15. R.P. Feazell, C.E. Carson, K.K. Klausmeyer, Inorg. Chem. 45, 2627 (2006)
16. A. Rodriguez, R. Kivekas, E. Colacio, Chem. Commun. 2005, 5228 (2005)
17. A. Petitjean, N. Kyritsakas, J.M. Lehn, Chem. Commun. 2004, 1168 (2004)
18. H. Grove, J. Sletten, M. Julve, F. Lloret, J. Chem. Soc., Dalton Trans. 2001, 2487 (2001)
19. M.H. Klingele, P.D.W. Boyd, B. Moubaraki, K.S. Murray, S. Brooker, Eur. J. Inorg. Chem. 2005,
910 (2005)
20. R. Lescouezec, F. Lloret, M. Julve, M. Verdaguer, Inorg. Chem. 41, 818 (2002)
21. A.Q. Wu, F.K. Zheng, G.C. Guo, Inorg. Chem. 43, 4839 (2004)
22. B.H. Ye, M.L. Tong, X.M. Chen, Coord. Chem. Rev. 249, 545 (2005)
23. S. Rupam, P. Dipak, Green Chem. 13, 718 (2011)
24. M.J. Percino, V.M. Chapela, O. Urzua, L.F. Montiel, C. Rodriguez-Barbarin, Res. Chem. Intermed.
33, 623 (2007)
25. K. Tanaka, F. Toda, Chem. Rev. 100, 1025 (2000)
26. R. Wang, M.Z. Sun, H. Jiang, Res. Chem. Intermed. 37, 61 (2011)
27. M. Chhanda, T.K. Pradip, Tetrahedron Lett. 49, 6237 (2008)
28. R.H. Abdol, G. Yosof, S. Nafisehsadat, E.R. Arnold, Synlett 741 (2010)
29. L.C. Rong, X.Y. Li, H.Y. Wang, D.Q. Shi, S.J. Tu, Chem. Lett. 35, 1314 (2006)
30. L.C. Rong, L.J. Gao, H.X. Han, H. Jiang, Y.S. Dai, S.J. Tu, Synth. Commun. 40, 289 (2010)
31. L.J. Gao, H.L. Ji, L.C. Rong, D. Tang, Y.Y. Zha, Y.H. Shi, S.J. Tu, J. Heteocyclic Chem. 48, 957
(2011)
32. P.Y. Rajendra, K.P. Praveen, K.P. Ravi, Orien. J. Chem. 23, 1069 (2007)
33. P.M. Raymond, J.Z. James, J. Org. Chem. 25, 647 (1960)
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