Synthesis of novel 4-amino-5-(disubstituted amino)-2-phenyl-2H-pyridazin-3-ones

Article abstract of DOI:10.1135/cccc19970800

Substituted 4-amino-2-phenyl-2H-pyridazin-3-ones 5a-5j have been prepared from 4-amino-5-chloro-2-phenyl-2H-pyridazin-3-one 1 which on reactions with acetyl chloride or acetic anhydride gives 4-acetylamino derivative 2 or 4-diacetylamino derivative 3, respectively. Derivatives 2 and 3 with dialkylamines and cyclic amines yielded appropriate 4-acetylamino-5-(disubstituted amino)-2-phenyl-2H-pyridazin-3-ones 4a-4j. Subsequent alkaline hydrolysis of the acetylamino derivatives 4a-4j let to the title compounds 5a-5j, which were screened for pesticidal activity, but none of them reached activity of the used standards.

Full text of DOI:10.1135/cccc19970800

800
Konecny, Zuziova, Kovac, Liptaj:
SYNTHESIS OF NOVEL 4-AMINO-5-(DISUBSTITUTED AMINO)-
-2-PHENYL-2H-PYRIDAZIN-3-ONES
a
b
c
d
Vaclav KONECNY , Jozefina ZUZIOVA , Stefan KOVAC and Tibor LIPTAJ
a Research Institute of Chemical Technology Plc, 836 06 Bratislava, Slovak Republic
b Department of Organic Chemistry, Slovak Technical University, 812 37 Bratislava,
Slovak Republic; e-mail: nemcova@checdek.chtf.stuba.sk
c Department of Chemistry, University of Trnava, 917 43 Trnava, Slovak Republic
d Central Laboratories, Slovak Technical University, 812 37 Bratislava, Slovak Republic;
e-mail: liptaj@cvtstu.cvt.stuba.sk
Received June 24, 1996
Accepted December 30, 1996
Substituted 4-amino-2-phenyl-2H-pyridazin-3-ones 5a–5j have been prepared from 4-amino-5-chloro-
2-phenyl-2H-pyridazin-3-one 1 which on reactions with acetyl chloride or acetic anhydride gives
4-acetylamino derivative 2 or 4-diacetylamino derivative 3, respectively. Derivatives 2 and 3 with
dialkylamines and cyclic amines yielded appropriate 4-acetylamino-5-(disubstituted amino)-2-phenyl-
2H-pyridazin-3-ones 4a–4j. Subsequent alkaline hydrolysis of the acetylamino derivatives 4a–4j let
to the title compounds 5a–5j, which were screened for pesticidal activity, but none of them reached
activity of the used standards.
Key words: 2H-Pyridazin-3-ones; Diazines; Pesticidal activity.
It is known that pyridazin-3-one derivatives have been in the foreground of scientific
research since 1970 (refs1–10). One reason was a production of 5-amino-4-chloro-2-phe-
nyl-2H-pyridazin-3-one (Pyramin) and its use as the herbicide by cultivating of sugar
beet11–14. In the present communication, the starting inactive isomer 4-amino-5-chloro-
2-phenyl-2H-pyridazin-3-one15 1 with acetyl chloride gave the corresponding 4-acetyl-
amino derivative 2 and with acetic anhydride the diacetylamino compound 3 (Scheme 1).
The reaction of 4-diacetylamino-5-chloro-2-phenyl-2H-pyridazin-3-one 3 with se-
condary or cyclic amines in molar ratio 1:2 afforded compounds 4a–4j as the main
products and the compound 2 as the by-product. The reaction of compounds 4a–4j with
bases such as trialkylamine, sodium hydroxide or sodium alcoholate in alcohol, water
or in their mixture from which sodium ethanolate appeared to be the most convenient,
afforded the compounds 5a–5j.
~
In the IR spectra, compounds 4a–4j display two ν(NH) bands in the 3 240–3 400
~
cm–1 region assigned to the intramolecularly bonded NH groups. The νs(NH2) and
~
νas(NH2) bands of compounds 5a–5j are observed in the 3 370–3 500 cm–1 region. The
~
ν(C=O) bands of carbonyl groups of the 2H-pyridazin-3-one ring are overlapped by the
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

2H-Pyridazin-3-ones
801
~
~
ν(C=N) and ν(C=C) bands owing to the very high absorption coefficients of the bands
at 1 610 cm–1. Also, the similar situation being observed in the spectra of compounds
5a–5j, only the ν(C=O) bands are shifted to higher wavenumbers.
~
Chemical shifts of the N–H protons of compounds 5f–5j having cyclic substituents
6
2
3
2 3
5
4
R R N
R R N
Cl
N
N
N
N
N
N
3
1
R
Ph
CH COHN
Ph
H N
2
Ph
3
O
O
O
5a-5j
4a-4j
1
1
R
R
= NH
2
= CH CONH
3
1,
2,
3,
3
2
R
4, 5
R
1
R
= (CH CO) N
3
2
a
b
c
d
e
f
CH
CH
3
3
C H
2
C H
2
5
7
5
5
7
9
C H
3
C H
3
C H
2
C H
4
i-C H
4
i-C H
4 9
9
C H
4
8
g
h
i
C H
5
10
12
C H
6
C H
7
14
j
(CH ) O(CH )
2 2 2 2
SCHEME 1
with except for 5j are observed at lower values than those of compounds 5a–5e, which
can be explained by steric effects. The highest chemical shift of the N–H proton in
compound 5j can be explained by the –I efect of the morpholine oxygen atom. Chemi-
cal shifts of α-protons of both ethyl and butyl groups overlap. Chemical shifts of the
C-5 and C-6 carbons increase with the ring enlargement. Chemical shifts of the C-4 and
C-6 carbons are observed at higher values than those of compounds 4a–4j whilst
chemical shifts of C-5 move in opposite direction. In the pesticide screening none of
the prepared compounds was as active as the standard used.
EXPERIMENTAL
Melting points were determined on Kofler apparatus and are uncorrected. All the compounds were
checked for the purity by TLC on Silufol UV 254 plates (Lachema Brno, Czech Republic) in the
system toluene–acetone 95 : 5 (v/v). Detection was carried out by UV-irradiation. Column chromato-
~
graphy was performed on silica gel (Lachema Brno, Czech Republic). The IR spectra, (ν, cm–1 ) were
recorded on an FTIR PU 9802/25 (Phillips) spectrophotometer in chloroform (c 10–2 mol dm–3, cell
thickness 0.1 mm). UV spectra (λ, nm; log ε) were obtained with the M-40 spectrophotometer (Zeiss
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

802
Konecny, Zuziova, Kovac, Liptaj:
Calculated/Found
TABLE I
Characteristic data for compounds 4a–4j and 5a–5j
M.p., °C
Yield, %
Formula
M.w.
Compound
% C
% H
% N
4a
4b
4c
4d
4e
4f
206–207
83
C
14H16N4O2
272.2
61.75
61.89
5.92
6.14
20.57
20.71
166–167
78
C16H20N4O2
300.3
63.99
64.21
6.71
6.80
18.66
19.01
148–150
81
C18H24N4O2
328.2
65.86
65.98
7.31
7.31
17.36
17.26
136–137
69
C18H24N4O2
328.2
65.86
65.98
7.31
7.35
17.36
17.18
162–163
87
C20H28N4O2
356.3
67.42
67.28
7.86
8.16
15.72
15.82
211–212
89
C16H18N4O2
298.1
64.45
64.21
6.04
5.90
18.78
18.82
4g
4h
4i
172–173
90
C17H20N4O2
312.2
65.39
65.49
6.41
6.52
17.94
17.86
157–159
72
C18H22N4O2
326.2
66.28
66.20
7.74
7.98
17.17
17.27
178–179
81
C19H24N4O2
340.2
67.08
67.23
7.05
7.02
16.46
16.57
4j
205–206
80
C16H18N4O2
314.2
61.15
61.04
5.73
5.74
17.82
17.64
5a
5b
5c
5d
5e
151–155
80
C12H14N4O
230.3
62.59
62.70
6.08
6.19
24.32
24.41
86–87
65
C14H18N4O
258.2
65.13
65.26
6.97
7.19
21.69
21.58
89–92
68
C16H22N4O
286.3
67.12
67.31
7.68
7.82
19.56
19.53
89–90
59
C16H22N4O
286.3
67.12
67.25
7.68
7.81
19.56
19.69
68–70
77
C18H26N4O
314.2
68.80
68.31
8.27
8.38
17.82
18.10
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

2H-Pyridazin-3-ones
803
TABLE I
(Continued)
Calculated/Found
% H
M.p., °C
Yield, %
Formula
M.w.
Compound
% C
% N
5f
5g
5h
5i
150–152
77
C
14H16N4O
256.2
65.62
65.71
6.25
6.21
21.86
21.98
172
73
C15H18N4O
270.2
66.66
66.80
6.66
6.90
20.72
21.00
122–123
67
C16H20N4O
284.2
67.62
67.44
7.03
7.08
19.70
19.64
95–96
71
C17H22N4O
298.2
68.46
68.51
7.37
7.38
18.78
18.89
5j
219–220
63
C14H16N4O2
272.2
61.77
61.64
5.88
5.74
20.57
20.41
1
Jena, Germany) in methanol (c 10–4 mol dm–3, cell thickness 0.2 cm). H NMR and 13C NMR spectra
were recorded on a Varian VXR-300 spectrometer at 300 (1H) and 75 (13C) MHz in hexadeuteriodi-
methyl sulfoxide with tetramethylsilane as internal standard. Chemical shifts are given in ppm (δ-
scale), coupling constants and width of multiplets in Hz. Mass spectra were recorded on an MS 902 S
spectrometer (70 eV) (A.E.I. Manchester, England).
Contact and systemic insecticidal activity was followed on Calandra granaria, Musca domestica,
Aphis fabae using Malathion and Fenitrothion as standards, acaricidal and ovicidal activity on Tetra-
nychus urticae, fungicidal activity was followed by the in vitro metod on fungi: Tilletia foetida, Bot-
rytis cinerea, Fusarium avenaceum, Alternaria alternata and by the in vivo mehtod on Erysiphe
graminis and Phytophtora infestans according to the published methods16,17, herbicidal activity with
the preemergent application on Avena fatua, Echinochloa cruss-gallii, Panicum miliaceum, Fagopy-
rum vulgare, Sinapis alba, Lepidium sativum and Beta vulgaris according to described methods18.
4-Acetylamino-5-chloro-2-phenyl-2H-pyridazin-3-one (2)
To acetyl chloride (200 cm3) 4-amino-5-chloro-2-phenyl-2H-pyridazin-3-one (1; 49.8 g, 0.225 mol)
was added and the reaction mixture was stirred under reflux 5 h. After cooling of the reaction mixture
to 0 °C, the solid portion was isolated and recrystallized from ethanol; 42.3 g (71 %) of the com-
pound 2, m.p. 176–180 °C, was obtained. IR spectrum: 1 725 (CH3CO), 1 625 (C=O + C=N), 3 275
1
(NH). UV spectrum (MeOH): 203 (4.52), 270 (3.69). H NMR spectrum: 2.11 s, 3 H (CH3CO), 8.43 s,
1 H (CH=N). 13C NMR spectrum: 167.37 (CH3CO), 157.36 (CO), 124.88 (C-4), 140.73 (C-5),
133.84 (C-6), 138.91 (C-1′), 125.27 (C-2′,6′), 129.03 (C-3′,5′), 128.51 (C-4′), 23.65 (CH3CO). Mass
•
•
spectrum, m/z: 263 (M+), 221 (M+ – CH2CO). For C12H10ClN3O2 (263.7) calculated: 54.66% C,
3.82% H, 13.44% Cl, 15.94% N; found: 54.51% C, 3.88% H, 13.51% Cl, 16.01% N.
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

804
Konecny, Zuziova, Kovac, Liptaj:
4-Diacetylamino-5-chloro-2-phenyl-2H-pyridazin-3-one (3)
To acetic anhydride (600 cm3) 4-amino-5-chloro-2-phenyl-2H-pyridazin-3-one (1; 49.8 g, 0.225 mol)
was added with stirring. The reaction mixture was stirred at reflux for 12 h. Acetic anhydride was
destilled off under reduced pressure, and the residue was purified by crystallization from toluene giv-
ing a crystalline compound (40.2 g, m.p. 97–99 °C), which was repurified by column chromato-
graphy on silica gel using toluene–acetone 95 : 5 (v/v) as eluent to yield compound 3 (35.1 g, 51%)
as white crystals, m.p. 100.7 °C. IR spectrum: 1 740 (CH3CO), 1 615 (C=O + C=N). UV spectrum
1
(MeOH): 265 (3.68), 318 (3.95). H NMR spectrum: 2.39 s, 6 H (CH3CO), 8.01 s, 1 H (CH=N). 13C NMR
TABLE II
IR and UV spectral data of compounds 4a–4j and 5a–5j
IR spectrum
UV spectrum
Compound
a
~
~
~
ν(C=O)
ν(NH)
ν(CH3C=O)
λmax(log ε)
4a
4b
4c
4d
4e
4f
1 612
1 612
1 612
1 612
1 614
1 612
1 614
1 612
1 162
1 618
1 635
1 639
1 637
1 637
1 637
1 626
1 630
1 629
1 631
1 641
3 246, 3 381
3 238, 3 377
3 238, 3 375
3 236, 3 375
3 248, 3 381
3 236, 3 389
3 248, 3 381
3 240, 3 379
3 244, 3 357
3 179, 3 373
3 379, 3 489
3 383, 3 499
3 385, 3 499
3 385, 3 499
3 387, 3 503
3 375, 3 487
3 373, 3 485
3 391, 3487
3 383, 3 497
3 379, 3 497
1 689
1 689
1 689
1 691
1 691
1 687
1 691
1 687
1 687
1 695
–
249(3.39), 308(3.06)
241(3.42), 308(3.06)
247(3.45), 310(3.17)
247(3.43), 310(3.12)
243(3.38), 306(3.09)
245(2.78), 309(2.39)
251(3.41), 313(3.13)
247(3.43), 310(2.90)
248(3.34), 310(3.02)
247(3.17), 311(2.92)
253(3.32), 333(2.82)
256(3.18), 333(2.69)
257(3.19), 333(2.69)
257(3.22), 333(2.75)
258(3.13), 333(2.63)
245(3.42), 309(3.05)
254(3.33), 333(2.90)
257(3.29), 333(2.78)
248(3.34), 333(2.88)
250(3.22), 333(2.68)
4g
4h
4i
4j
5a
5b
5c
5d
5e
5f
–
–
–
–
–
5g
5h
5i
–
–
–
5j
–
a ~
~
νs (NH2) and νas (NH2) for compounds 5a–5j.
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

2H-Pyridazin-3-ones
805
TABLE III
1H NMR spectra of the non-phenylic moiety of compounds 4a–4j and 5a–5j
Compound
1H NMR spectrum
4a
4b
2.00 s, 3 H (CH3CO); 2.85 s, 6 H (CH3); 8.01 s, 1 H (CH=N); 9.12 s, 1 H (NH)
1.21 t, 6 H (CH3CH2); 1.97 s, 3 H (CH3CO); 3.35 q, 4 H (CH3CH2); 7.95 s, 1 H
(CH=N); 9.02 s, 1 H (NH)
4c
0.84 t, 6 H (CH3); 1.54 m, 4 H (CH2-β); 1.98 s, 3 H (CH3CO); 3.29 t, 4 H (CH2-α);
7.98 s, 1 H (CH=N); 9.08 s, 1 H (NH)
4d
0.87 t, 3 H (CH3); 1.09 t, 3 H (CH3CH2N); 1.32 sext. 2 H (CH2-γ); 1.52 quin. 2 H
(CH2-β); 1.97 s, 3 H (CH3CO); 3.30 m, 4 H (CH2-α); 7.96 s, 1 H (CH=N); 9.07 s,
1 H (NH)
4e
4f
4g
4h
4i
0.80 d, 12 H (CH3); 1.78 sext. 2 H (CH); 2.00 s, 3 H (CH3CO); 3.22 d, 4 H (CH2); 8.09
s, 1 H (CH=N); 9.15 s, 1 H (NH)
1.84 m, 4 H (CH2-β); 1.96 s, 3 H (CH3CO); 3.47 t, 4 H (CH2-α); 7.91 s, 1 H (CH=N);
8.97 s, 1 H (NH)
1.55–1.50 m, 6 H (CH2-β + CH2-γ); 2.01 s, 3 H (CH3CO); 3.31 t, 4 H (CH2-α); 8.01 s,
1 H (CH=N); 9.17 s, 1 H (NH)
1.49 m, 4 H (CH2-γ); 1.72 m, 4 H (CH2-β); 1.98 s, 3 H (CH3CO); 3.54 t, 4 H (CH2-α);
8.00 s, 1 H (CH=N); 9.15 s, 1 H (NH)
1.52–1.50 m, 6 H (CH2-γ + CH2-δ); 1.63 m, 4 H (CH2-β); 1.98 s, 3 H (CH3CO); 3.53 t,
4 H (CH2-α); 8.01 s, 1 H (CH=N); 9.21 s, 1 H (NH)
4j
2.02 s, 3 H (CH3CO); 3.05 t, 4 H (CH2-α); 3.79 t, 4 H (CH2-β); 8.05 s, 1 H (CH=N);
9.48 s, 1 H (NH)
5a
5b
5c
2.67 s, 6 H (CH3); 5.79 s, 2 H (NH2); 7.85 s, 1 H (CH=N)
0.98 t, 6 H (CH3); 2.99 q, 4 H (CH2); 5.76 s, 2 H (NH2); 7.82 s, 1 H (CH=N)
0.84 t, 6 H (CH3); 1.40 m, 4 H (CH2-β); 2.91 t, 4 H (CH2-α); 5.73 s, 2 H (NH2);
7.84 s, 1 H (CH=N)
5d
5e
0.86 t, 3 H (CH3-butyl); 0.99 t, 3 H (CH3-ethyl); 1.12 t, 2 H (CH2-γ); 1.30 m, 2 H
(CH2-β); 2.97 m, 4 H (CH2-α); 5.70 s, 2 H (NH2); 7.83 s, 1 H (CH=N)
0.86 d, 12 H (CH3); 1.71 m, 2 H (CH); 3.22 t, 4 H (CH2); 5.58 s, 2 H (NH2);
7.91 s, 1 H (CH=N)
5f
1.85 t, 4 H (CH2-β); 3.26 t, 4 H (CH2-α); 5.34 s, 2 H (NH2); 7.81 s, 1 H (C=N)
5g
1.68 m, 2 H (CH2-γ); 1.70 m, 4 H (CH2-β); 3.17 t, 4 H (CH2-α); 5.29 s, 2 H (NH2);
7.91 s, 1 H (CH=N)
5h
5i
1.69 m, 4 H (CH2-γ); 1.71 m, 4 H (CH2-β); 3.18 t, 4 H (CH2-α); 5.47 s, 2 H (NH2);
7.84 s, 1 H (CH=N)
1.52–1.50 m, 6 H (CH2-(γ + δ)); 1.63 m, 4 H (CH2-β); 3.28 t, 4 H (CH2-α); 5.35 s,
2 H (NH2); 7.87 s, 1 H (CH=N)
5j
2.92 t, 4 H (CH2-α); 3.75 t, (CH2-β); 5.93 s, 2 H (NH2); 7.86 s, 1 H (C=N)
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

806
Konecny, Zuziova, Kovac, Liptaj:
TABLE IV
13C NMR spectra of the compounds 4a–4j and 5a–5j
Compound
13C NMR spectrum
4a
4b
4c
22.6 (COCH3), 40.3 (CH3N), 127.3 (C-4′), 128.8 (C-3′,5′), 125.3 (C-2′,6′), 141.7 (C-1′),
110.6 (C-4), 144.7 (C-5), 138.4 (C-6), 158.7 (C=O), 168.6 (CH3CO)
13.8 (CH3), 22.5 (COCH3), 44.5 (CH2), 127.2 (C-4′), 128.4 (C-3′,5′), 125.2 (C-2′,6′),
141.7 (C-1′), 110.7 (C-4), 143.4 (C-5), 132.2 (C-6), 158.8 (C=O), 169.0 (CH3CO)
10.9 (CH3), 21.5 (CH2-β), 22.5 (COCH3), 52.4 (CH2-α), 127.2 (C-4′), 128.4 (C-3′,5′),
125.1 (C-2′,6′), 141.7 (C-1′), 110.5 (C-4), 143.2 (C-5), 132.2 (C-6), 158.7 (C=O),
169.3 (CH3CO)
4d
4e
13.8 (CH3), 19.5 (CH2-γ), 22.5 (COCH3), 30.4 (CH2-βbutyl), 45.4 (CH2-αethyl),
49.9 (CH2-αbutyl), 127.2 (C-4′), 128.0 (C-3′,5′), 125.2 (C-2′,6′), 141.6 (C-1′), 110.5 (C-4),
143.3 (C-5), 132.0 (C-6), 158.8 (C=O), 169.3 (CH3CO)
19.7 (CH3), 22.4 (COCH3), 27.3 (CH), 59.6 (CH2), 127.2 (C-4′), 128.4 (C-3′,5′),
125.1 (C-2′,6′), 141.6 (C-1′), 111.3 (C-4), 143.4 (C-5), 132.7 (C-6), 158.6 (C=O),
169.0 (CH3CO)
4f
22.5 (COCH3), 24.9 (CH2-β), 48.8 (CH2-α), 127.1 (C-4′), 128.4 (C-3′,5′), 125.2 (C-2′,6′),
141.8 (C-1′), 108.2 (C-4), 142.2 (C-5), 131.6 (C-6), 158.9 (C=O), 169.6 (CH3CO)
4g
22.5 (COCH3), 23.7 (CH2-γ), 25.7 (CH2-β), 48.2 (CH2-α), 127.3 (C-4′), 128.5 (C-3′,5′),
125.3 (C-2′,6′), 141.6 (C-1′), 113.7 (C-4), 144.5 (C-5), 134.1 (C-6), 158.7 (C=O),
168.1 (CH3CO)
4h
4i
22.5 (COCH3), 26.2 (CH2-γ), 28.1 (CH2-β), 50.5 (CH2-α), 127.2 (C-4′), 128.4 (C-3′,5′),
125.2 (C-2′,6′), 141.7 (C-1′), 109.7 (C-4), 144.0 (C-5), 131.8 (C-6), 158.9 (C=O),
169.1 (CH3CO)
22.5 (COCH3), 23.9 (CH2-γ), 26.6 (CH2-β), 26.8 (CH2-δ), 51.6 (CH2-α), 127.2 (C-4′),
128.4 (C-3′,5′), 125.1 (C-2′,6′), 141.6 (C-1′), 109.8 (C-4), 143.0 (C-5), 131.8 (C-6),
158.8 (C=O), 169.3 (CH3CO)
4j
5a
5b
5c
5d
22.5 (COCH3), 47.4 (CH2-α), 63.2 (CH2-β), 127.5 (C-4′), 128.5 (C-3′,5′), 125.4 (C-2′,6′),
141.6 (C-1′), 114.7 (C-4), 143.8 (C-5), 131.8 (C-6), 158.8 (C=O), 168.3 (CH3CO)
41.2 (CH3N), 125.7 (C-2′,6′), 127.4 (C-4′), 128.4 (C-3′,5′), 142.1 (C-1′), 128.2 (C-4),
134.6 (C-5), 133.7 (C-6), 156.2 (C=O)
12.6 (CH3), 45.2 (CH2), 125.6 (C-2′,6′), 127.3 (C-4′), 128.4 (C-3′,5′), 142.1 (C-1′),
124.6 (C-4), 138.7 (C-5), 136.2 (C-6), 156.3 (C=O)
11.5 (CH3), 20.3 (CH2-β), 53.2 (CH2-α), 125.6 (C-2′6′), 127.4 (C-4′), 128.4 (C-3′,5′),
142.1 (C-1′), 125.2 (C-4), 137.9 (C-5), 136.3 (C-6), 156.3 (C=O)
13.7 (CH3ethyl, butyl), 19.7 (CH2-γ), 29.3 (CH2-β), 45.6 (CH2-αbutyl), 125.5 (C-2′,6′),
127.3 (C-4′), 128.3 (C-3′,5′), 142.2 (C-1′), 124.8 (C-4), 138.3 (C-5), 136.2 (C-6),
156.2 (C=O)
5e
5f
20.5 (CH3), 26.5 (CH), 59.4 (CH2), 125.6 (C-2′,6′), 127.4 (C-4′), 128.4 (C-3′,5′),
142.1 (C-1′), 126.4 (C-4), 138.5 (C-5), 136.4 (C-6), 156.3 (C=O)
24.3 (CH2-β), 48.6 (CH2-α), 125.5 (C-2′,6′), 127.3 (C-4′), 128.4 (C-3′,5′), 142.2 (C-1′),
127.6 (C-4),130.1 (C-5), 132.5 (C-6), 156.4 (C=O)
5g
25.9 (CH2-γ), 29.1 (CH2-β), 51.1 (CH2-α), 125.5 (C-2′,6′), 127.3 (C-4′), 128.4 (3′,5′),
142.0 (C-1′), 128.1 (C-4), 132.1 (C-5), 135.1 (C-6), 156.3 (C=O)
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

2H-Pyridazin-3-ones
807
TABLE IV
(Continued)
13C NMR spectrum
Compound
5h
5i
26.8 (CH2-γ), 28.8 (CH2-β), 51.9 (CH2-α), 125.5 (C-2′,6′), 127.4 (C-4′), 128.4 (3′,5′),
142.0 (C-1′), 129.5 (C-4), 133.9 (C-5), 135.4 (C-6), 156.4 (C=O)
24.7 (CH2-γ), 26.9 (CH2-δ), 27.6 (CH2-β), 50.9 (CH2-α), 125.4 (C-2′,6′),
127.3 (C-4′), 128.3 (3′,5′), 141.9 (C-1′), 128.7 (C-4), 133.6 (C-5), 136.0 (C-6),
156.5 (C=O)
5j
49.2 (CH2-α), 66.3 (CH2-β), 125.7 (C-2′,6′), 127.5 (C-4′), 128.5 (C-3′,5′), 142.1 (C-1′),
126.4 (C-4), 135.8 (C-5), 133.8 (C-6), 156.3 (C=O)
spectrum: 170.49 (CH3CO), 156.84 (CO), 118.25 (C-4), 140.47 (C-5), 136.57 (C-6), 140.21 (C-1′),
•
124.88 (C-2′,6′), 128.90 (C-3′,5′), 127.32 (C-4′), 25.43 (CH3CO). Mass spectrum, m/z: 305 (M+), 263
•
•
(M+ – CH2CO), 77 (C6H5+). For C14H12ClN3O3 (305.7) calculated: 55.00% C, 3.96% H, 11.60% Cl,
13.75% N; found: 55.10% C, 3.99% H, 11.71% Cl, 13.81% N.
General Procedure for Preparation of 4-Acetylamino-5-(disubstituted amino)-2-phenyl-2H-pyridazin-
3-ones 4b–4j
Procedure A. To 4-diacetylamino-5-chloro-2-phenyl-2H-pyridazin-3-one (3; 6.1 g, 0.02 mol)) in
toluene (80 cm3) an appropriate secondary or cyclic amine (0.04 mol) excepting dimethylamine, was
added with stirring and the reaction mixture was stirred at boiling temperature for 3 h. After cooling
the solid portion was filtered off, triturated with water, dried, and the residue was chromatographed
on a column of silica gel (200 g). By TLC it was found that two compounds were formed which
were separated by elution with toluene containing acetone (10 g per 100 cm3). A side product was
found to be 4-acetylamino-5-chloro-2-phenyl-2H-pyridazin-3-one 2. The characteristic data, infrared
and UV spectra of the compounds 4 are given in Tables I and II, their NMR spectra in Tables III and IV.
Procedure B. To 4-acetylamino-5-chloro-2-phenyl-2H-pyridazin-3-one (2; 5.2 g, 0.02 mol) in toluene
(80 cm3) an appropriate amine (0.04 mol) excepting dimethylamine, was added with stirring for 4 h.
The raw products were collected by filtration, washed with water, dried and purified by crystal-
lization from ethanol.
4-Acetylamino-5-dimethylamino-2-phenyl-2H-pyridazin-3-one (4a)
Dimethylamine (1.8 g, 0.04 mol) cooled to 0 °C was added to 4-acetylamino-5-chloro-2-phenyl-2H-
pyridazin-3-one (2; 5.2 g, 0.02 mol) in toluene (80 cm3) with stirring. The reaction mixture was then
heated in autoclave at 150 °C for 6 h. After cooling to 10 °C, the solid portion was filtered off,
triturated with water dried and recrystallized from ethanol. Its characteristic data, infrared and UV
spectra are given in Tables I and II, NMR spectra in Tables III and IV.
Collect. Czech. Chem. Commun. (Vol. 62) (1997)

808
Konecny, Zuziova, Kovac, Liptaj:
General Procedure for Preparation of 4-Amino-5-(disubstituted amino)-2-phenyl-2H-pyridazin-3-ones
5a–5j
To sodium ethanolate prepared from ethanol (30 cm3) and sodium (0.2 g) the 4-acetylamino deriva-
tives 4a–4j (0.01 mol) were added and the reaction mixture was refluxed 4 h and then slowly cooled
to room temperature with stirring. Ethanol was distilled off under reduced pressure. Crystallization of the
residues from a suitable solvent yielded the corresponding amino derivatives 5a–5j. Their characteristic
data, infrared and UV spectra are given in Tables I and II, their NMR spectra in Tables III and IV.
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