Reaction of 4,5-dichloro-2-chloromethylpyridazin-3(2H)-one with phenols

Article abstract of DOI:10.1002/jhet.83

(Chemical Equation Presented) The regiochemistry was investigated for the reaction of 2-chloromethyl-4,5-dichloropyridazin-3(2H)-one (1) with some phenols 2 in the presence of a base in organic solvents. Seven diphenoxy derivatives 5 were synthesized sele

Full text of DOI:10.1002/jhet.83

410
Reaction of 4,5-Dichloro-2-chloromethylpyridazin-3(2H)-one
with phenols
Vol 46
Seung-Beom Kang, Song-Eun Park, Hyung-Geun Lee, Bo Ram Kim,
Kwang-Ju Jung, Ju-Eun Won, Min-Jung Kim, and Yong-Jin Yoon*
Department of Chemistry & Environmental Biotechnology National Core Research Center,
Research Institute of Natural Science, Graduate School for Materials and Nanochemistry,
Gyeongsang National University, Jinju 660-701, Korea
*E-mail: yjyoon@gnu.ac.kr
Received September 1, 2008
DOI 10.1002/jhet.83
Published online 7 May 2009 in Wiley InterScience (www.interscience.wiley.com).
The regiochemistry was investigated for the reaction of 2-chloromethyl-4,5-dichloropyridazin-3(2H)-
one (1) with some phenols 2 in the presence of a base in organic solvents. Seven diphenoxy derivatives
5 were synthesized selectively from 1 and phenols 2 under two optimized conditions. The product distri-
butions of these reactions are dependent on the base, the solvent, and/or the substitutes of phenols.
J. Heterocyclic Chem., 46, 410 (2009).
INTRODUCTION
RESULTS AND DISCUSSION
Chloromethyl-4,5-dichloropyridazin-3(2H)-one (1) is
a key intermediate for the synthesis of their derivatives,
fluorescence molecules containing pyridazinone ring
[1,2], and also biologically active compounds [3–7].
Because of involving four electrophilic carbons such as
ClCH2N-, C-3, C-4, and C-5, however, the reaction of
compound 1 with a nucleophile such as phenol affords
two or three products [8,9]. Also, the retro-ene reaction
of compound 1 under basic condition was reported [9].
Based upon the atomic charges of compound 1 [10], the
reactivity of the C-5 position about the nucleophile is
more active than the a-C and C-4 positions (Fig. 1).
Therefore, the selective synthesis of 5-phenoxy-2-phe-
noxymethyl-, 5-phenoxy-, or 2-phenoxymethyl deriva-
tive under basic condition is difficult.
First, we examined the effect of the bases in the reac-
tion of 1 with o-vaniline (2a) in acetonitrile. Reaction of
compound 1 with two equivalents o-vaniline (2a) in the
presence of base in refluxing acetonitrile gave products
3a, 4a, and 5a. The distribution of the products for these
reactions is shown in Table 1.
When K2CO3, Cs2CO3, and Na2CO3 as the base were
used, compound 5a was the main product. However, the
reaction did not progress using NaH, Et3N, and N,N-
dimethylaminopyridine as base in refluxing acetonitrile.
We selected potassium carbonate as the suitable base for
this reaction.
On the other hand, we examined the effect of the sol-
vents for the same reaction under different conditions
such as at reflux temperature or under microwave
irradiation.
In connection with the SAR study and the evaluation
of biological activity such as cardiovascular activity or
immunosuppressive activity, we need some 2-(phenoxy-
Although two products were detected, the reaction of
1 with 2a in acetonitrile, ethyl acetate, tetrahydrofuran,
or acetone under the same conditions gave 5a as the
main product (entries 1, 2, 5, 6, 7, 8, 9, and 10, in Table
2). Compound 1 was reacted with 2a in the presence of
potassium carbonate in refluxing methanol or under
microwave irradiation to afford selectively 5a in
methyl)-5-phenoxylpyridazin-3(2H)-ones.
Thus,
we
attempted to study on the regiochemistry in the reaction
of compound 1 with phenols under basic condition
(Scheme 1). In this article, we report the results for the
title reactions.
C
V
2009 HeteroCorporation

May 2009
Reaction of 4,5-Dichloro-2-Chloromethylpyridazin-3(2H)-one with Phenols
411
Scheme 1
Figure 1. Atomic charge of carbons at the MP2/6-311þG** for com-
pound 1.
excellent yield, respectively (entries 3 and 4 in Table 2).
Compound 4a was the main product when refluxing tol-
uene was used, whereas the reaction did not occur in
toluene under microwave irradiation. Even though the
conversion ratio of 1 was low, 4a was the main product
in the reaction in methylene chloride and diethyl
ether under microwave irradiation (entries 14 and 16 in
Table 2). We did not find significant differences for the
distribution of the products between the classical heating
system and microwave irradiation system. According to
TLC analysis, the product 5a yielded via the 2-phenoxy-
methyl compound 4a in the reaction of 1 with 2a,
whereas the 5-phenoxy derivative 3a did not convert to
5a under the same condition. Based upon the selectivity
and the practical reaction conditions, therefore, we
selected the optimized conditions, that is, (i) refluxing
acetonitrile/potassium carbonate system and (ii) reflux-
ing methanol/potassium carbonate system. Using the
two optimized system, we investigated the effect of the
substitutes of phenols. Most interestingly, reaction of 1
with 2b (2 equiv.) or 2e (2 equiv.) under two optimized
conditions gave selectively the corresponding 5-phenoxy
derivatives 3b or 3e in excellent yields (entries 1, 2, 7,
and 8 in Table 3). Treatment of 1 with 2j under our two
conditions also afforded selectively a-phenoxy deriva-
tive 4j in excellent yield (entries 17 and 18 in Table 3).
Although compound 1 was reacted with 2c in refluxing
acetonitrile to afford 4c (48%) and 5c (46%), the same
reaction was carried out in refluxing methanol to give
selectively 5c in 94% yield (entries 3 and 4 in Table 3).
On the other hand, compound 1 was reacted with 2d or
2f–2i under the same conditions to afford selectively a-
diphenoxy derivatives 5d or 5f–5i in good to excellent
yields, respectively (entries 5–6 and 9–16 in Table 3).
The chemical structures of the all products were charac-
terized by IR spectroscopy, NMR spectroscopy, and the
elemental analysis.
CONCLUSIONS
In conclusion, the regiochemistry was investigated for
the reaction of compound 1 with some phenols 2 in the
presence of a base in organic solvents. Although diphe-
noxy derivatives 5 were synthesized selectively under
two optimized conditions, we did not find any regular-
ity. Although significant differences for the distribution
of the products did not show under the classical heating
system and microwave irradiation, the regiochemistry in
Table 1
Screening of bases for the reactions of one equivalent of 1 with two equivalents of 2a in acetonitrile.a
Product (%)b
Reaction time
(hours)
Entry
Base
Conversion ratiob
3a
4a
5a
1
2
3
4
5
6
K2CO3
Cs2CO3
Na2CO3
NaH
1.5
1
100
100
100
0
–
1
7
33
40
–
93
66
48
–
13
48
48
48
12
–
Et3N
DMAPc
0
0
–
–
–
–
–
–
a Mole ratio of reactants:2/3a ¼ 1:2 equivalents.
b Determination by using proton NMR.
c N,N-Dimethylaminopyridine.
Journal of Heterocyclic Chemistry
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S.-B. Kang, S.-E. Park, H.-G. Lee, B. R. Kim, K.-J. Jung, J.-E. Won, M.-J. Kim, and Y.-J. Yoon Vol 46
Table 2
The products distribution for the reactions of 1 with 2a in the presence of K2CO3 in organic solvents.a
Product (%)c
Entry
Solvent
CH3CN
Reaction conditionsb
Conversion ratioc
3a
4a
5a
1
2
Reflux,1.5 h
MW, 1.5 h
Reflux, 1h
MW, 0.5 h
Reflux, 14 h
MW, 5 h
Reflux, 48 h
MW, 5 h
Reflux, 24 h
MW,2 h
100
100
100
100
100
73
100
90
100
100
100
0
–
–
7
8
93
92
100
100
50
48
32
43
54
50
32
–
3
MeOH
EtOAc
THF
–
–
4
5
–
2
–
48
44
23
42
36
42
64
–
6
7
8
45
15
10
8
8
9
Acetone
Toluene
CH2Cl2
Ether
10
11
12
13
14
15
16d
17
18
Reflux, 32 h
MW, 5 h
4
–
Reflux, 48 h
MW, 5 h
0
78
–
4
–
80
–
63
–
–
16
–
12
–
Reflux, 48 h
MW, 1 h
0
59
–
25
–
n-Hexane
Reflux, 48 h
MW, 5 h
0
0
–
–
–
a Mole ratio of reactants:2/3a ¼ 1:2 equivalents.
b MW ¼ Microwave irradiation.
c Determination by using proton NMR.
d After 30 minutes, the solvent was refilled.
Table 3
The products distribution for the reactions of 1 with 2 in the presence of potassium carbonate in acetonitrile or methanol.a
Product (%)b
Entry
2
Reaction conditions
3
4
5
1
2
2b
CH3CN, 13 h
MeOH, 1 h
3b(93)
3b(94)
–
–
–
–
–
4c(48)
–
3
4
2c
2d
2e
2f
CH3CN, 8 h
MeOH, 5 h
5c(46)
5c(94)
5d(93)
5d(94)
–
–
5
6
CH3CN, 9 h
MeOH, 12 h
CH3CN, 34 h
MeOH, 20 h
CH3CN, 4 h
MeOH, 2 h
CH3CN, 0.2 h
MeOH, 10 min
CH3CN, 1 h
MeOH, 20 min
CH3CN, 3 h
MeOH, 2h
–
–
–
–
3e(90)
3e(95)
7
–
8
9
–
–
–
–
–
–
–
–
–
–
–
–
5f(90)
5f(92)
5g(94)
5g(95)
5h(84)
5h(90)
5i(89)
5i(91)
–
10
11
12
13
14
15
16
17
18
–
–
2g
2h
2i
–
–
–
–
–
2j
CH3CN, 60 h
MeOH, 48 h
4j(85)
4j(90)
–
a Mole ratio of reactants:2/3a ¼ 1:2 equivalents.
b Isolated yields.
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Reaction of 4,5-Dichloro-2-Chloromethylpyridazin-3(2H)-one with Phenols
413
(CDCl3): d 81.58, 124.51, 129.94, 134.90, 136.66, 137.53,
144.20, 155.33, 156.82 ppm; Elemental analysis calcd. for
C12H7Cl4N3O4: C, 36.12; H, 1.77; N, 10.53. Found: C, 36.17;
H, 1.79; N, 10.57.
2-[(4,5-Dichloro-6-oxopyridazin-l(6H)-yl)methoxy]-3-metho-
xybenzaldehyde (4a). Prepared by the Method 1 and 2. mp
143ꢁC. IR (KBr) 3077, 3011, 2993, 2885, 2846, 1695, 1666,
1615, 1581, 1481, 1460, 1392, 1278, 1250,1217 cmꢂ1 1H
;
the reaction is effected by the base, the solvent, and/or
the substitutes of phenols. Further work including the
theoretical study on the regiochemistry and the biologi-
cal activity are under way in our laboratory.
EXPERIMENTAL
Melting points were determined with a capillary apparatus
1
NMR (CDCl3): d 3.91 (s, 3H), 6.09 (s, 2H, N-CH2), 7.16 (d,
2H, J ¼ 3 Hz), 7.34 (t, 1H, J ¼ 5.1 Hz), 7.72 (s, 1H), 10.16
ppm (s, 1H); 13C NMR (CDCl3): d 56.21, 81.44, 117.99,
119.41, 125.34, 129.93, 134.87, 136.33, 137.20, 148.32,
152.35, 156.58, 189.73 ppm; Elemental analysis calcd. for
C13H10Cl2N2O4: C,47.44; H,3.06; N, 8.51; Found: C, 47.49;
H, 3.11; N, 8.58.
4,5-Dichloro-2-[(2,6-dichlorophenoxy)methyl]pyridazin-
3(2H)-one (4c). Prepared by the Method 1. mp 142ꢁC. IR
(KBr) 3093, 3053, 1676, 1663, 1584, 1456, 1440, 1402, 1297,
1242, 1224, 1003, 990, 962 cmꢂ1 1H NMR (CDCl3): d 6.03
;
(s, 2H), 7.05 (t, 1H, J ¼ 8.15 Hz), 7.29 (m, 2H), 7.72 ppm (s,
1H); 13C NMR (CDCl3): d 81.46, 126.17, 129.07, 129.14,
134.84, 136.12, 137.17, 149.68, 156.80 ppm; Elemental analy-
sis calcd. for C11H6Cl4N2O2: C, 38.86; H, 1.78; N, 8.24.
Found: C, 38.90; H, 1.82; N, 8.27.
4,5-Dichloro-2-((2,4-dinitrophenoxy)methyl)pyridazin-
3(2H)-one (4j). Prepared by the Method 1. mp 147–149ꢁC. IR
(KBr) 3095, 3062, 1681, 1607, 1586, 1525, 1349, 1273, 1249,
;
987, 964 cmꢂ1 1H NMR (CDCl3): d 6.24 (s, 2H), 7.75 (d,
and uncorrected. H and 13C NMR spectra were recorded on a
300 MHz spectrophotometer with chemical shift values
reported in d units (ppm) relative to an internal standard
(TMS). IR spectra were obtained on an IR spectrophotometer.
Elemental analyses were performed with a CHNS-932 (Leco).
2-Chloromethyl-4,5-dichloropyridazin-3(2H)-one was synthe-
sized by the literature method [2]. Microwave reaction was
carried out by using a CEM, Discover microwave apparatus.
General procedure for the reaction of 2-chloromethyl-4,5-
dichloropyridazin-3(2H)-one (1) with phenols (2).
Method 1. A solution of 2-hydroxy-3-methoxybenzaldehyde
(2.8 g, 2 equiv.) and base (2 equiv.), 2-chloromethyl-4,5-
dichloro-pyridazin-3(2H)-one (2) (2 g, 1 equiv.), and solvent
(30 mL) was refluxed until 2 disappeared by TLC monitoring.
After cooling the mixture to room temperature, the mixture
was filtered and concentrated. The distribution of products was
1
analyzed by H NMR quantitative analysis. The products 3, 4,
and 5 were also isolated by column chromatography on silica
gel (2.5 ꢀ 8 cm) with n-hexane/EtOAc (2:1, v/v).
Method 2. 2-Chloromethyl-4,5-dichloropyridazin-3(2H)-one
(2) (0.1 g, 1 equiv.) was dissolved in solvent (7 mL) in a 10
mL microwave vessel. 2-Hydroxy-3-methoxybenzaldehyde
(0.14 g, 2 equiv.) and base (2 equiv.) were added. The vessel
was closed and placed into a microwave apparatus. The mix-
ture was irradiated per 10 min at 120ꢁC with a set power of
300 W. After cooling, the mixture was filtered on a glass filter
under vacuum. The distribution of products was analyzed by
1H NMR quantitative analysis.
1H, J ¼ 9.24 Hz), 7.90 (s, 1H), 8.47 (dd, 1H, J ¼ 2.77, 6.45
Hz), 8.70 ppm (d, 1H, J ¼ 2.74 Hz); 13C NMR (CDCl3): d
79.10, 117.90, 121.72, 128.99, 135.14, 137.46, 137.85, 140.17,
141.90, 154.30, 156.62 ppm; Elemental analysis calcd. for
C11H6Cl2N4O6: C, 36.59; H, 1.67; N, 15.52. Found: C, 36.63;
H, 1.70; N, 15.58.
2-(5-Chloro-l-((2-formyl-6-methoxyphenoxy)methyl)-6-oxo-
l,6-dihydropyridazin-4-yloxy)-3-methoxybenzaldehyde (5a).
Prepared by the Method 1 and 2. mp 165ꢁC. IR (KBr): 3085,
3021, 2988, 2946, 2843, 1694, 1663, 1617, 1584, 1482, 1461,
2-(5-Chloro-l-chloromethyl-6-oxo-l,6-dihydropyridazin-4-
yloxy)-3-methoxybenzaldehyde (3a). Prepared by the Method
1 and 2. mp; 145ꢁC. IR (KBr) 3081, 3045, 2935, 2878, 1663,
1394, 1377, 1312, 1271, 1248, 990 cmꢂ1 1H NMR (CDCl3):
;
1
1581, 1479, 1452, 1387, 1254, 1213 cmꢂ1; H NMR (CDCl3):
d 3.86 (s, 3H), 3.96 (s, 3H), 6.15 (s, 2H), 7.19 (d, 2H, J ¼ 6
Hz), 7.28 (t, 1H, J ¼ 4.5 Hz), 7.33 (s, 1H), 7.38 (t, 1H, J ¼
3.8 Hz), 7.43 (s, 1H, J ¼ 8.1 Hz), 7.56 (dd, 1H, J ¼ 1.2, 7.7
Hz), 10.19 (s, 1H, CHO), 10.31 ppm (s, 1H, CHO); 13C NMR
(CDCl3): d 56.20, 56.44, 80.85, 117.91, 118.21, 119.00,
120.74, 125.27, 127.52, 129.15, 129.41, 142.98, 151.15,
152.49, 153.71, 187.80, 189.82 ppm; Elemental analysis calcd.
for C21H17ClN2O7: C, 56.70; H, 3.85; N, 6.30; Found: C,
56.75; H, 3.87; N, 6.34.
4-Chloro-5-(2,6-dichlorophenoxy)-2-[(2,6-dichloro-phen-
oxy)-methyl]pyridazin-3(2H)-one (5c). Prepared by the
Method 1. mp 145–147ꢁC. IR (KBr): 3074, 3054, 2923, 1674,
1445, 1270 1237 cmꢂ1 1H NMR (CDCl3): d 6.04 (s, 2H),
;
7.05 (m, 1H), 7.29 (m, 3H), 7.44 (d, 2H, J ¼ 8.11 Hz), 7.72
ppm (s, 1H); 13C NMR (CDCl3): d 81.15, 126.04, 126.17,
128.11, 128.16, 128.98, 129.07, 129.25, 129.47, 136.12,
145.21, 152.46, 158.90 ppm; Elemental analysis calcd. for
C17H9Cl5N2O3: C, 43.77; H, 1.94; N, 6.00. Found: C, 43.79;
H, 2.00; N, 6.07.
4-Chloro-5-(2,5-dichlorophenoxy)-2-[(2,5-dichlorophenoxy)-
methyl]pyridazin-3(2H)-one (5d). Prepared by the Method 1.
mp 143ꢁC. IR (KBr): 3073, 3057, 3018, 1659, 1612, 1578,
d 3.87 (s, 3H), 5.86 (s, 2H, N-CH2), 7.35 (d, 1H, J ¼ 6 Hz),
7.42 (s, 1H), 7.46 (t, 1H, J ¼ 6 Hz), 7.58 (d, 1H, J ¼ 6 Hz),
10.30 ppm (s, CHO 1H); 13C NMR (CDCl3): d 56.55, 58.29,
118.31, 121.12, 127.71, 129.26, 130.17, 142.79, 151.25,
153.83, 157.77, 187.75 ppm; Elemental analysis calcd. for
C13H10Cl2N2O4: C,47.44; H,3.06; N, 8.51; Found: C, 47.50;
H, 3.10; N, 8.57.
4-Chloro-2-(chloromethyl)-5-phenoxypyridazin-3-(2H)-one
(3b). Prepared by the Method 1. mp 78ꢁC. IR (KBr) 3067,
3011, 1660, 1609, 1585, 1487, 1393, 1311, 1278, 1216, 1155
cmꢂ1
;
1H NMR (CDCl3): d 5.85 (s, 2H), 7.11 (d, 2H, J ¼
7.64 Hz), 7.32 (m, 1H), 7.48 (m, 2H), 7.53 ppm (s, 1H); 13C
NMR (CDCl3): d 58.29, 115.99, 119.79, 126.42, 130.55,
130.62, 131.23, 153.31, 153.72 ppm; Elemental analysis calcd.
for C11H8Cl2N2O2: C, 48.73; H, 2.97; N, 10.33. Found: C,
48.80; H, 3.00; N, 10.37.
4-Chloro-2-chloromethyl-5-[(2,6-dichloro-4-nitrophenoxy)
methyl]pyridazin-3(2H)-one (3e). Prepared by the Method 1.
mp 152ꢁC. IR(KBr) 3086, 3054, 1678, 1588, 1523, 1506,
1
1349, 1293, 1249, 1215, 973, 956 cmꢂ1; H NMR (CDCl3): d
6.11 (s, 2H), 7.77 (s, 1H), 8.21 ppm (s. 2H); 13C NMR
Journal of Heterocyclic Chemistry
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1474, 1434, 1393, 1379, 1273, 1255, 1220, 1161, 1137 cmꢂ1
.
C19H15ClN4O7: C, 51.08; H, 3.38; N, 12.54. Found: C, 51.11,
H, 3.40; N, 12.57.
4-Chloro-5-(4-nitrophenoxy)-2-[(4-nitrophenoxy) methyl]-
pyridazin-3(2H)-one (5i). Prepared by the Method 1. mp
177–178ꢁ. IR (KBr): 3073, 3057, 1659, 1612, 1578, 1474,
1393, 1379, 1273, 1220, 1095 cmꢂ1 1H NMR (CDCl3): d
;
6.15 (s, 2H), 7.26 (m, 4H), 7.69 (s, 1H), 8.33 ppm (m, 4H);
13C NMR (CDCl3): d 83.90, 115.83, 118.75, 123.80, 125.99,
126.45, 131.81, 142.81, 144.98, 151.96, 158.23, 158.37,
161.27 ppm; Elemental analysis calcd. for C17H11ClN4O7: C,
48.76; H, 2.65; N, 13.38. Found: C, 48.79; H, 2.70; N, 13.41.
1H NMR (CDCl3): d 6.05 (s, 2H), 7.02 (dd, 1H, J ¼ 2.26,
6.27 Hz), 7.22 (d, 1H, J ¼ 2.30 Hz), 7.30 (m, 3H), 7.47 ppm
(t, 2H, J ¼ 8.59 Hz); 13C NMR (CDCl3): d 79.41, 118.54,
120.22, 122.31, 123.35, 124.22, 124.72, 127.88, 129.64,
131.06, 131.96, 133.12, 134.05, 149.26, 152.68, 153.00,
158.49 ppm; Elemental analysis calcd. for C17H9Cl5N2O3: C,
43.77; H, 1.94; N, 6.00. Found: C, 43.80; H, 2.02; N, 6.09.
2-(5-Chloro-l-[(3-ethoxy-2-formylphenoxy)methyl]-6-oxo-
l,6-dihydropyridazin-4-yloxy)-6-ethoxybenzaldehyde
(5f).
Prepared by the Method 1. mp 188ꢁC. IR (KBr): 2987, 2975,
2930, 2893, 2861, 1693, 1666, 1616, 1583, 1483, 1469, 1394,
1378, 1319, 1269, 1246, 1214, 1181, 1159, 1049, 987 cmꢂ1
;
Acknowledgments. The authors acknowledge support by a grant
from the Korea Science and Engineering Foundation (KOSEF) to
the Environmental Biotechnology National Core Research Center
(grant number: R15-2003-012-02001-0).
1H NMR (CDCl3):d 1.26 (t, 3H, J ¼ 6.87 Hz), 1.52 (t, 3H, J
¼ 6.89 Hz), 4.16 (m, 4H), 6.17 (s, 2H), 7.35 (m, 7H), 10.19
(s, 1H), 10.32 ppm (s, 1H); 13C NMR (CDCl3): d 14.42,
14.87, 64.84, 65.25, 80.88, 118.95, 119.01, 119.21, 120.54,
125.09, 127.37, 129.17, 129.77, 12996, 143.46, 148.79,
150.43, 153.88, 158.77, 187.87, 189.88 ppm; Elemental analy-
sis calcd. for C23H22Cl N2O7: C, 58.29; H, 4.68; N, 5.91.
Found: C, 58.32; H, 4.71; N, 5.97.
REFERENCES AND NOTES
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4-Chloro-5-(3,4-difluorophenoxy)-2-((3,4-difluorophenoxy)
methyl)pyridazin-3(2H)-one (5g). Prepared by the Method 1.
liquid. IR (KBr) 3083, 1681, 1668, 1513, 1270, 1252, 1206,
1160, 1132, 1031 cmꢂ1 1H NMR (CDCl3): d 5.98 (s, 2H),
;
7.26 (m, 6H), 7.56 ppm (s, 1H); 13C NMR (CDCl3): d 78.45,
106.16, 106.43, 109.70, 109.97, 111.76, 115.60, 117.31,
117.55, 118.40, 118.67, 120.97, 130.29, 148.77, 151.88,
153.13, 158.54 ppm; Elemental analysis calcd. for
C17H9ClF4N2O3: C, 50.95; H, 2.26; N, 6.99.Found: C, 51.01;
H, 2.30; N, 7.02.
4-Chloro-5-(3-methyl-4-nitrophenoxy)-2-[(3-methyl-4-nitro-
phenoxy)methyl]-pyridazin-3-(2H)-one (5h). Prepared by the
Method 1. mp 128–129ꢁC. IR (KBr): 3072, 3032, 1672, 1580,
[7] Konecny, V.; Kovac, S.; Varkonda, S. Chemicke Zvesti
(Czech.) 1984, 38, 239.
1
1515, 1483, 1343, 1236, 1081, 1051 cmꢂ1; H NMR (CDCl3):
[8] Chung, H.-A.; Kim, J. J.; Kim, H. K.; Kweon, D. H.; Cho,
S. D.; Lee, S. G.; Yoon, Y. J. J Heterocycl Chem 2005, 42, 639.
[9] Chung, H.-A.; Kang, Y. J.; Yoon, Y. J. J Heterocycl Chem
1998, 35, 1257.
d 2.63 (d, 6H, J ¼ 10.26 Hz), 6.12 (s, 1H), 7.09 (m, 4H), 7.68
(s, 1H), 8.12 ppm (m, 2H); 13C NMR (CDCl3): d 21.02, 21.46,
53.49, 113.34, 116.58, 119.36, 122.12, 123.16, 127.46, 127.72,
131.60, 137.06, 137.62, 143.51, 146.02, 152.15, 156.46,
158.39, 159.68 ppm; Elemental analysis calcd. for
[10] Yoon, Y. J.; Koo, I. S.; Park, J. K. Bull Korean Chem Soc
2007, 28, 1363.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet