Pyridazine and its related compounds. Part 36. Synthesis and antimicrobial activity of some novel pyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine derivatives

Article abstract of DOI:10.1007/s00044-014-1011-3

Novel derivatives of pyrimidothienopyridazine were designed and synthesized through a versatile method. Some of the target compounds bearing the sulfonamide group were evaluated for their antimicrobial activity against representative Gram-positive bacteria, Gram-negative bacteria, and fungi by applying the agar plate diffusion technique. The results showed that derivatives 11a have promising inhibitory activity against Gram-positive bacteria, and derivatives 11b and 11e have also potent inhibition against fungi. Rest of the compounds showed moderate to low activity against the examined micro-organisms.

Full text of DOI:10.1007/s00044-014-1011-3

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-014-1011-3
ORIGINAL RESEARCH
Pyridazine and its related compounds. Part 36. Synthesis
and antimicrobial activity of some novel
0
0
pyrimido[4 ,5 :4,5]thieno[2,3-c]pyridazine derivatives
Ali Deeb Sebaey Mahgoub
•
Received: 30 September 2013 / Accepted: 14 April 2014
Ó Springer Science+Business Media New York 2014
Abstract Novel derivatives of pyrimidothienopyridazine
were designed and synthesized through a versatile method.
Some of the target compounds bearing the sulfonamide
group were evaluated for their antimicrobial activity
against representative Gram-positive bacteria, Gram-neg-
ative bacteria, and fungi by applying the agar plate diffu-
sion technique. The results showed that derivatives 11a
have promising inhibitory activity against Gram-positive
bacteria, and derivatives 11b and 11e have also potent
inhibition against fungi. Rest of the compounds showed
moderate to low activity against the examined micro-
organisms.
activities, and plant growth regulators and crop protecting
agents (Tucaliuc et al., 2008). On the other hand, many
fused compounds with thienopyrimidine fragment have
received considerable interest because of their remarkable
pharmacological properties (Chambhare et al., 2003).
Literature survey reveals that sulfonamides are important
class of pharmaceutical compounds exhibiting a wide spec-
trum of biological activity (Hansch et al., 1990, Connor, 1998
and Hanson et al., 1999), and over 30 drugs containing this
functionality are in clinical use, including, antibacterial agents,
diuretics, anticonvulsants, hypoglycemic, and HIV protease
inhibitors (Kleemann et al., 1999 and Deeb et al., 2014).
In the light of these facts, our interest was focused on
synthesizing new heterocyclic compounds including pyri-
midothienopyridazine moieties with suitable substituent of
biological and pharmacological interest. The structures of
the newly synthesized compounds were elucidated on the
basis of elemental analysis and various spectroscopic
methods and in some cases by comparison with samples
previously prepared by unambiguous route. Some of the
newly prepared compounds were preliminarily evaluated
for their in vitro antibacterial activities against (Micro-
coccus luteus and Staphylococcus aureus) as representative
examples of Gram-positive bacteria and (Escherichia coli)
as an example of Gram-negative bacteria. They were
evaluated for in vitro antifungal activity against (Candida
albicans) as representative fungi.
Keywords Thienopyridazine ꢀ
Pyrimidothienopyridazine ꢀ Sulfonamide ꢀ
Antimicrobial activity
Introduction
Pyridazine and its fused heterocyclic derivatives have
recently received much attention from their reactions, syn-
thetic and effective biological importance. It have been
reported to possess antimicrobial (Kandile et al., 2009; Asif
et al., 2011), antituberculosis (Mangalagiu, 2011 and Mantu
et al.,2010), antifungal (Drochioiu et al., 2007), anticancer
(
Butnariu et al., 2007), herbicidal (Han et al.,2010)
Materials and methods
Taken in part from M.Sc. thesis of Sebaey Mahgoub, Zagazig
University, 2013.
Chemistry
A. Deeb (&) ꢀ S. Mahgoub
Department of Chemistry, Faculty of Science, Zagazig
University, Zagazig, Egypt
e-mail: dralideeb@hotmail.com
All melting points were determined in open-glass capil-
laries and are uncorrected. IR spectra were recorded on a
123

Med Chem Res
1
BRUKER Vector 22 Germany spectrometer (KBr). H-
0
00
9 ), 159.0 (C=O), 155.5 (C-3), 148.3 (C-4 ), 144.7 (C-6),
0
NMR spectra were recorded on Varian Gemini 200 MHz
143.3 (C-8 ), 135.9 (C-4), 134.5–126.0 (2Ph). Anal. Calcd
1
3
spectrometer and
125 MHz), using tetramethylsilane as an internal refer-
ence. The Electron Impact mass spectra were obtained at
0 eV using Shimadzu QP-2010 Plus mass spectrometer.
C-NMR spectra on JMS-AX500
for C H N OS (356.4): C, 67.40; H, 3.39; N, 15.72.
0 12 4
2
(
Found: C, 67.25; H, 3.20; N, 15.55.
7
Preparation of 8-chloro-3,4-
0
0
The reactions were followed up by thin-layer chromatog-
raphy (TLC) on silica gel F254 aluminum sheets (Merck),
and the spots were detected by UV lamp at 254–365 nm.
The synthesis of ethyl 5-amino-3,4-diphenylthieno[2,3-
c]pyridazine-6-carboxylate 1 (Deeb et al., 1990) was con-
ducted according to known procedure.
diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyridazine (4)
A mixture of compound 3 (1.0 g, 2.8 mmol) and phos-
phoryl chloride (15 mL) was heated at reflux temperature
for 4 h. The reaction mixture was cooled and hydrolyzed
by addition of crushed ice. The formed precipitate was
filtered, washed with water, dried, and recrystallized from
ethanol to give 4, yield 66.6 %, mp 145–147 °C; IR (KBr,
Antimicrobial activity
-
1
?
cm ): 1604 (C=N), 1071 (C–Cl); MS (m/z, %): 374 [M ,
1
13.1 %], 315 [M –N = C–Cl, 11.51 %], 57[100 %]; H-
?
The antimicrobial activity study was performed using
standard cultures of M. luteus ATCC10240, S. aureus
ATCC6538P, E. coli ATCC10536, and C. albicans
ATCC2091. M. luteus, S. aureus, and E. coli cultures were
incubated in Nutrient Broth (Difco), while C. albicans was
incubated in Sabouraud Dextrose Broth (Difco), and
dimethylformamide was used as a solvent for tested com-
pounds. A blank disk impregnated with dimethylformam-
ide followed by drying off was used as a negative control.
Sulfadoxine, Sulfadimidine, and Nystatin at concentration
of 400 lg/0.1 mL in dimethylformamide were used as
positive control.
NMR (DMSO-d ): d (ppm) = 8.2 (s, 1H, H-6), 7.6–7.3 (m,
10H, 2Ph); C-NMR (DMSO-d ): d (ppm): 161.9 (C-4 ),
6
1
3
00
6
0
159.3 (C-9 ), 156.7 (C-6), 155.5 (C-3), 154.1 (C–Cl), 135.9
(C-4), 134.5–126.3 (2Ph). Anal. Calcd for C H ClN S
11
2
0
4
(374.8): C, 64.08; H, 2.96; N, 14.95. Found: C, 63.90; H,
2.80; N, 14.85.
0
0
0
0
Preparation of 7,8-diphenyltetrazolo[1 ’,5 ’:1 ,6 ]pyrimido
0
0
[4 ,5 :4,5]thieno[2,3-c]pyridazine (5)
A solution of 4 (1.0 g, 2.6 mmol) and sodium azide
(0.34 g, 5.2 mmol) in ethanol (25 mL) was refluxed for
Preparation of ethyl 5-[(ethoxymethylene)amino]-3,4-
4 h. The solvent was evaporated in vacuo, and the residue
was washed with water, filtered, dried, and recrystallized
from ethanol to give 5, yellow crystals, yield 89.1 %; mp
diphenylthieno[2,3-c]pyridazine-6-carboxylate (2)
-
1
A stirred mixture of ethyl 5-amino-3,4-diphenylthieno[2,3-
c]pyridazine-6-carboxylate 1 (1.0 g, 2.6 mmol) in triethyl
orthoformate (20 mL) and acetic anhydride (1.0 mL) was
refluxed for 6 h. The reaction mixture was evaporated
under reduced pressure, and the product 2 was used directly
in next steps without further purification.
248–250 °C; IR (KBr, cm ): 1635 (C=N); MS (m/z, %):
? ?
381 [M , 20.69 %], 357 [M –N , 24.14 %, F ],327 [F –
2
1
1
1
N , 21.38 %, F ]; H-NMR (DMSO-d ): d (ppm) = 9.2 (s,
2
2
6
1
3
1H, H-6), 7.7–7.4 (m, 10H, 2Ph); C-NMR (DMSO-d ): d
6
0
0
0
(ppm): 161.9 (C-4 ), 159.3 (C-9 ), 155.5 (C-3), 154.1 (C–
Cl), 140.3 (C-6), 135.9 (C-4), 134.5–126.3 (2Ph). Anal.
Calcd for C H N S (381.4): C, 62.98; H, 2.91; N, 25.71.
2
0 11 7
0
0
Preparation of 3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
Found: C, 62.83; H, 2.80; N, 25.55.
c]pyridazin-8(7H)-one (3)
0
0
Preparation of 3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
A solution of compound 2 (1.0 g, 2.9 mmol) in concen-
trated ammonium hydroxide solution (20 mL) was stirred
at 70 °C for 8 h. The reaction mixture was filtered; the
filtrate was neutralized with conc. HCl. The precipitated
product was filtered, washed with water and recrystallized
from ethanol to give 3, yellow crystals, yield 48.4 %; mp
c]pyridazine-8(7H)-thione (6)
A solution of 4 (1.0 g, 2.6 mmol) and thiourea (1.0 g,
1.3 mmol) in ethanol (30 mL) was refluxed for 4 h, the
solvent was evaporated on vacuo, and the residue was
heated in sodium hydroxide solution (50 mL, 2.5 N) for
30 min and then filtered while hot. The filtrate was cooled
and acidified with hydrochloric acid (pH 2), the yellow
precipitate obtained was filtered, washed with water, dried,
and recrystallized from ethanol to give 6, yield 80.8 %, mp
-
1
1
88–190 °C; IR (KBr, cm ): 3165 (NH), 1655 (C=O); MS
m/z, %): 356 [M , 73.03 %], 314 [M –NCO, 87.64 %,
? ?
(
F ], 288 [F –HCN, 61.80 %, F ], 232 [F –SCH CH ,
2
1
1
2
2
2
1
6
0.67 %, F ], 205 [F –N , 60.67 %, F ]; H-NMR (DMSO-
3 3 2 4
-
1
d ): d (ppm) = 8.8 (s, 1H, NH), 7.9 (s, 1H, H-6), 7.7–7.4
230–232 °C; IR (KBr, cm ): 3390 (NH), 1665 (C=N),
1531 (C=C), 1194 (C=S); MS (m/z, %): 372 [M ,
6
1
3
?
(
m, 10H, 2Ph); C-NMR (DMSO-d ): d (ppm): 162.5 (C-
6
1
23

Med Chem Res
1
4
7.24 %], 85 [100 %];
H-NMR (DMSO-d6):
d
ppm) = 12.2 (s, 1H, NH), 8.1 (s, 1H, H-6), 7.8–7.4 (m,
C, 70.57; H, 3.73; N, 15.24. Found: C, 70.40; H, 3.63; N,
15.10.
(
1
3
1
1
0H, 2Ph); C-NMR (DMSO-d ): d (ppm): 175.7 (C=S),
55.5 (C-3), 152.3 (C-9 ), 142.3 (C-6), 138.3 (C-4 ), 135.9
6
0
00
7-((4-Methoxybenzylidene)amino)-3,4-diphenylpyrimido
0
0
(
(
C-4), 133.5–125.3 (2Ph). Anal. Calcd for C H N S
0 12 4 2
[4 ,5 :4,5]thieno[2,3-c]pyridazin-8(7H)-one (8b)
2
372.4): C, 64.49; H, 3.25; N, 15.04. Found: C, 64.24; H,
.09; N, 14.90.
3
Brown crystals; yield 76.3 %; mp 170–172 °C; IR (KBr,
cm ): 3054 (CHarom), 2990 (CHaliph), 1665 (C=O), 1630
-
1
0
0
?
(C=N), 1079 (OCH ); MS (m/z, %): 489 [M , 17.21 %],
Preparation of 7-amino-3,4-diphenylpyrimido[4 ,5 :4,5]
3
?
458 [M –OCH 17.80 %, F ], 384 [F –Ph, 18.40 %, F ],
thieno[2,3-c]pyridazin-8(7H)-one (7)
3
,
1
1
2
3
42 [F –CH N , 23.44 %, F ], 288 [F –NCO, 22.55 %,
2 2 2 3 3
1
To solution of compound 2 (1.0 g, 2.9 mmol) in glacial
acetic acid (10 mL), hydrazine hydrate 85 % (2.0 mL,
F4]; H-NMR (DMSO-d ): d (ppm) = 9.1 (s, 1H,
6
N=CHPh), 8.2 (s, 1H, H-6), 7.89–7.05 (m, 15H, 3Ph), 3.5
3
1
1
9.0 mmol) was added. The reaction mixture was refluxed
(s, 1H, CH3); C-NMR (DMSO-d ): d (ppm): 162.5 (C-
6
0
for 8 h, left to cool at room temperature and the precipi-
tated product was filtered, washed with water, and recrys-
tallized from ethanol to give 7, yellow crystals, yield
9 ), 161.9 (C–O),160.9 (C=O) 155.5 (C-3), 153.1
0
0
(N=CHPh), 148.3 (C-4 ), 145.8 (C-6), 135.9 (C-4),
133.7–114.5 (3Ph) 55 (CH3). Anal. Calcd for
C H N O S (489.5): C, 68.70; H, 3.91; N, 14.31. Found:
-
1
3
4.9 %; mp 180–182 °C; IR (KBr, cm ): 3414, 3150
2
8 19 5 2
(
NH ), 3057 (CH ), 1676 (C=O), 1594 (C=N); MS (m/
C, 68.55; H, 3.75; N, 14.21.
2
arom
?
z, %): 371 [M , 9.95 %], 342 [M –N , 2.21 %, F ],
?
2
1
2
89[F –NCO, 1.70 %, F ], 233 [F –CH CH SH, 3.74 %,
1
7-((4-Nitrobenzylidene)amino)-3,4-diphenylpyrimido
0
2
2
2
2
1
0
F ],204 [F –N , 1.96 %, F ]; H-NMR (DMSO-d ): d
[4 ,5 :4,5]thieno[2,3-c]pyridazin-8(7H)-one (8c)
3
3
2
4
6
(
ppm) = 8.1 (s, 1H, H-6), 7.7–7.5 (m, 10H, 2Ph), 2.3 (s,
3
1
0
1
1
1
H, NH); C-NMR (DMSO-d ): d (ppm): 162.7 (C-9 ),
Brown crystals; yield 74.0 %; mp 125–127 °C; IR (KBr,
6
0
0
-1
cm ): 3056 (CH
59.5 (C = O), 155.5 (C-3), 148.3 (C-4 ), 145.8 (C-6),
), 1658 (C=O), 1519, 1437 (NO ); MS
arom 2
?
(m/z, %): 504 [M , 15.47 %], 460 [M –NO , 21.07 %,
?
35.9 (C-4), 134.5–127.3 (2Ph). Anal. Calcd for
2
C H N OS (371.4): C, 64.68; H, 3.53; N, 18.86. Found:
2
F ], 383 [F - Ph, 18.67 %, F ], 341 [F - CH N , 16.80 %,
2 2
0
13
5
1
1
2
2
C, 64.50; H, 3.43; N, 18.70.
F ],288 [F –NCO, 14.40 %, F ], 260 [F –N , 19.47 %, F ];
3 3 4 4 2 5
1
H-NMR (DMSO-d6):
d
N = CHPh), 8.2 (s, 1H, H-6), 7.95–7.42 (m, 14H, 3Ph);
(ppm) = 9.01 (s, 1H,
General procedure for the synthesis of 7-(arylideneamino)-
0
0
13
0
C-NMR (DMSO-d ): d (ppm): 162.3 (C-9 ), 161.5
(C=O), 156.1 (C-3), 153.8 (N=CHPh), 159.8 (C-NO2),
3
,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyridazin-8
6
(
7H)-one derivatives (8a–c)
0
0
1
49.1 (C-4 ), 146.1 (C-6), 136.7 (C-4), 129.7–124.5 (3Ph).
A mixture of compound 7 (1.0 g, 2.6 mmol) and the appro-
priate aldehyde, namely benzaldehyde, p-methoxybenzade-
hyde, and p-nitrobenzaldehyde (2.6 mmol), was refluxed in
ethanol (20 mL) for 4 h. The solvent was evaporated under
reduced pressure, and the residue was triturated with diethyl
ether (20 mL). The separated solid was filtered, dried, and
recrystallized from ethanol to give 8a–c.
Anal. Calcd for C H N O S (504.5): C, 64.28; H, 3.20;
27 16 6 3
N, 16.66. Found: C, 64.10; H, 3.06; N, 16.50.
General procedure for the preparation of 7-N-substituted
0
0
3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyridazin-
8(7H)-one (9a–d)
To a solution of compound 2 (1.0 g, 2.9 mmol) in glacial
acetic acid (10 mL), substituted amines (2.9 mmol) were
added, the reaction mixture was refluxed for 8 h, cooled
and the formed precipitate was filtered, washed with water,
and recrystallized from appropriate solvent to give 9a–d.
0 0
-(Benzylideneamino)-3,4-diphenylpyrimido[4 ,5 :4,5]
7
thieno[2,3-c]pyridazin-8(7H)-one (8a)
Brown crystals; yield 81.3 %; mp 205–207 °C; IR (KBr,
cm ): 3056 (CHarom), 1687 (C=O), 1630, 1620 (C=N);
-
1
?
MS (m/z, %): 459 [M , 49.09 %], 357 [M –PhCN,
?
0
0
7-Benzyl-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
1
6.36 %, F ], 317 [F –NCO, 69.09 %, F ]; H-NMR
5
c]pyridazin-8(7H)-one (9a)
1
1
2
(
DMSO-d ): d (ppm) = 9.1 (s, 1H, N = CHPh), 8.2 (s, 1H,
6
1
3
H-6), 7.89–7.42 (m, 15H, 3Ph); C-NMR (DMSO-d ): d
Yellow crystals from chloroform, yield 48.5 %; mp
-1
6
0
(
ppm): 162.5 (C-9 ), 161.5 (C=O), 155.5 (C-3), 153.3
0
283–285 °C. IR (KBr, cm ): 3058 (CHarom), 2916 (CH
), 1676 (C=O), 1597 (C=N); MS (m/z): 446 [M ,
liph
a-
?
0
(
CH=NPh), 148.3 (C-4 ), 146.9 (C-6), 136.9 (C-4),
33.7–127.5 (3Ph). Anal. Calcd for C H N OS (459.5):
?
1
2.67 %], 370 [M –C H , 1.32 %, F ], 341 [F –NCH ,
6
2
7
17
5
5
1
1
3
123

Med Chem Res
1
.69 %, F ], 288 [F –N = CHCHO, 1.76 %, F ]; H-NMR
1
Calcd for C H N O S (476.55): C, 70.57; H, 4.23; N,
28 20 4 2
2
2
3
(
DMSO-d ): d (ppm) = 8.2 (s, 1H, H-6), 7.69–7.26 (m,
11.76. Found: C, 70.41; H, 4.08; N, 11.60.
6
1
3
1
5H, 3Ph), 4.2 (s, 2H, CH Ph); C-NMR (DMSO-d ): d
2
6
0
(
ppm): 162.5 (C-9 ), 160.3 (C = O), 156.5 (C-3), 147.3 (C-
General procedure for the preparation of 7-substituted 3,4-
0
0
6
), 136.9 (C-4), 135.7–126.5 (3Ph), 47.1 (CH Ph). Anal.
2
diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyridazin-8(7H)-
Calcd for C H N OS (446.5): C, 72.63; H, 4.06; N,
27 18 4
one (11a–g)
1
2.55. Found: C, 72.48; H, 3.90; N, 12.41.
To a solution of compound 2 (1.0 g, 2.9 mmol) in glacial
acetic acid (10 mL), N‘-substituted 4-aminobenzenesulf-
onamides 10a–g (2.9 mmol) were added, the reaction mix-
ture was refluxed for 8 h, cooled and the formed precipitate
was filtered, washed with water, dried, and recrystallized
from appropriate solvent to give pure 11a–g.
0 0
-(2-Chlorobenzyl)-3,4-diphenylpyrimido[4 ,5 :4,5]thieno
7
[
2,3-c]pyridazin-8(7H)-one (9b)
Yellow crystals from chloroform; yield 54.05 %; mp
-
1
2
75–277 °C; IR (KBr, cm ): 3060 (CHarom), 2917 (CH
liph), 1677 (C=O), 1597 (C=N); MS (m/z): 480 [M ,
a-
?
?
.89 %], 446 [M –Cl, 0.17 %, F ], 355 [F –PhCH ,
0
0
0
0
0
4-(8-Oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
1
1
3
.58 %, F ],313 [F –NCO, 4.93 %, F ], 287 [F –N ,
2
c]pyridazin-7(8H)-yl)benzenesulfonamide (11a)
2
2
3
3
1
.01 %, F ]; H-NMR (DMSO-d ): d (ppm) = 8.3 (s, 1H,
H-6), 7.81–7.26 (m, 14H, 3Ph), 4.91 (s, 2H, CH Ph); C-
2
4
6
1
3
Yellow crystals, yield 59.3 %; mp 180–182 °C; IR (KBr,
0
-1
cm ): 3390, 3150 (NH ), 3054 (CHarom), 1664 (C=O),
NMR (DMSO-d ): d (ppm): 163.1 (C-9 ), 160.1 (C=O),
6
2
1
4
6
1
56.4 (C-3), 148.1 (C-6), 137.2 (C-4), 135.4–127.3 (3Ph),
1566 (C=N), 1337, 1134 (SO ); MS (m/z, %): 512
2
?
[M ? 1, 4.56 %], 448 [M –SO , 0.85 %, F ], 432 [F –
?
2.3 (CH Ph). Anal. Calcd for C H ClN OS (480.9): C,
27 17
2
4
2
1
1
7.42; H, 3.56; N, 11.65. Found: C, 67.27; H, 3.40; N,
1.50.
NH , 1.07 %, F ], 356 [F –Ph, 0.35 %, F ], 312 [F –NCO,
2 2 2 3 3
1
3.68 %, F ]; H-NMR (DMSO-d ): d (ppm) = 8.5 (s, 1H,
4
6
1
H-6), 8.1–7.52 (m, 14H, 3Ph), 2.3 (s, 2H, NH2); C-NMR
3
0
0
0
3
,4-Diphenyl-7-(phenylamino)pyrimido[4 ,5 :4,5]thieno
(DMSO-d ): d (ppm): 162.4 (C-9 ), 161.2 (C=O), 156.2 (C-
6
[
2,3-c]pyridazin-8(7H)-one (9c)
3), 147.5 (C-6), 136.5 (C–S), 133.4–121.3 (3Ph). Anal.
Calcd for C H N O S (511.5): C, 61.04; H, 3.35; N,
26 17 5 3 2
Yellow crystals from chloroform; yield 57.8 %; mp
13.69. Found: C, 60.90; H, 3.20; N, 13.50.
-
1
2
1
0
90–292 °C; IR (KBr, cm ): 3390 (NH), 3059 (CHarom),
?
677 (C=O), 1596 (C=N); MS (m/z, %): 447 [M ,
0
0
4-(8-Oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
?
.58 %], 370 [M –Ph, 3.65 %, F ], 342 [F –N , 0.45 %,
c]pyridazin-7(8H)-yl)-N-phenylbenzene sulfonamide (11b)
1
1
2
F ], 287 [F –NCO, 0.38 %, F ], 260[F –N , 1.15 %, F ];
2
2
3
3
2
4
1
H-NMR (DMSO-d ): d (ppm) = 8.4 (s, 1H, H-6),
Yellow crystals from chloroform; yield 51.4 %, mp
-1
6
1
.81–6.5 (m, 15H, 3Ph), 4.3 (s, 1H, NH); C-NMR
3
7
207–209 °C; IR (KBr, cm ): 3115 (NH), 3061 (CHarom),
0
(
DMSO-d ): d (ppm): 162.9 (C-9 ), 159.9 (C=O), 155.9 (C-
1672 (C=O), 1592 (C=N), 1324, 1163 (SO ); MS (m/z, %):
?
6
2
?
3
), 147.9 (C-6), 136.89 (C-4), 135.4–127.0 (3Ph). Anal.
587 [M , 0.03 %], 523 [M –SO , 0.08 %, F ], 432 [F –
2 1 1
1
PhNH , 0.06 %, F ], 313 [F –PhNCO, 0.05 %, F ]; H-
Calcd for C H N OS (447.5): C, 69.78; H, 3.83; N,
6
2
17
5
2
2
2
3
1
5.65. Found: C, 69.63; H, 3.68; N, 15.52.
NMR (DMSO-d ): d (ppm) = 10.2 (s, 1H, NH), 8.5 (s, 1H,
6
1
3
H-6), 8.0–6.52 (m, 19H, 4Ph); C-NMR (DMSO-d ): d
6
0
0
0
7
-(4-Hydroxyphenethyl)-3,4-diphenylpyrimido[4 ,5 :4,5]
(ppm): 163.1 (C-9 ), 159.2 (C=O), 155.7 (C-3), 146.6 (C-
thieno[2,3-c]pyridazin-8(7H)-one (9d)
6), 133.4–119.3 (4Ph). Anal. Calcd for C H N O S
2 21 5 3 2
3
(587.6): C, 65.40; H, 3.60; N, 11.92. Found: C, 65.26; H,
Yellow crystals from chloroform, yield 46.5 %; mp
3.44; N, 11.76.
-
1
2
2
4
0
0
96–298 °C; IR (KBr, cm ): 3425 (OH), 3058 (CHarom),
0
0
916 (CH ), 1676 (C=O), 1597 (C=N); MS (m/z, %):
N-(4-Chlorophenyl)-4-(8-oxo-3,4-diphenylpyrimido[4 ,5 :4,5]
aliph
?
76 [M , 0.27 %], 461 [M –OH, 0.54 %, F ], 384 [F –Ph,
?
thieno[2,3-c]pyridazin-7(8H)-yl) benzenesulfonamide (11c)
1
1
.90 %, F ], 356 [F –CH CH , 6.81 %, F ], 329 [F –CN,
2
2
2
2
3
3
1
.72 %, F ], 288 [F –NCO, 0.72 %, F ]; H-NMR
Yellow crystals from chloroform; yield 34.7 %, mp
-
235–237 °C; IR (KBr, cm ): 3259 (NH), 3062 (CHarom),
1670 (C=O), 1592 (C=N), 1325, 1164 (SO ); MS (m/z, %):
?
621 [M , 1.34 %], 511 [M –PhCl, 0.64 %, F ], 448 [F –
1 1
4
4
5
1
(
DMSO-d ): d (ppm) = 8.6 (s, 1H, H-6), 7.81–6.3 (m,
6
1
4H, 3Ph), 5.9 (s, 1H, OH), 3.5 (t, 2H, CH N), 2.9 (t, 2H,
2
2
1
3
0
?
CH Ph); C-NMR (DMSO-d ): d (ppm): 162.5 (C-9 ),
2
6
1
1
60.5 (C=O), 156.7 (C-3), 153.6 (C–O), 146.9 (C-6),
SO , 0.61 %, F ], 356 [F –PhNH , 0.35 %, F ]; H-NMR
2 2 2 2 3
1
33.4–115.0 (3Ph), 48.2 (CH N), 40.1 (CH Ph). Anal.
2
(DMSO-d ): d (ppm) = 10.3 (s, 1H, NH), 8.4 (s, 1H, H-6),
2
6
1
23

Med Chem Res
1
3
7
.8–7.22 (m, 18H, 4Ph); C-NMR (DMSO-d ): d (ppm):
N’-(2,4-Dinitrophenyl)-4-(8-oxo-3,4-diphenylpyrimido
0
6
0
0
1
62.9 (C-9 ), 158.9 (C = O), 156.2 (C-3), 145.9 (C-6),
[4 ,5 :4,5]thieno[2,3-c]pyridazin-7(8H)-yl)
1
34.1–122.3 (4Ph). Anal. Calcd for C H ClN O S
5 3 2
benzenesulfonohydrazide (11g)
3
2
20
(6
21.1): C, 61.78; H, 3.24; N, 11.26. Found: C, 61.63; H,
3
.10; N, 11.11.
Yellow crystals from ethanol; yield 37.5 %, mp
-
1
2
54–256 °C; IR (KBr, cm ): 3390, 3170 (2NH), 3059
(CHarom), 1677 (C=O), 1596 (C=N), 1490, 1444 (NO ),
); MS (m/z, %): 694 [M ? 2, 2.97 %],
04 [M –2NO , 3.76 %, F ], 511 [F –PhNH , 1.03 %,
0
0
4
-(8-Oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyri-
2
?
dazin-7(8H)-yl)-N-(o-tolyl)benzene sulfonamide (11d)
1322, 1174 (SO
2
?
6
F
F
2
1
1
2
Yellow crystals from acetic acid; yield 50.4 %, mp
2
4
], 433 [F
], 285 [F
2
–SO
–N
2
, 3.84 %, F
, 5.63 %, F
3
], 313 [F
1
5
3
–PhNCO, 4.34 %,
-1
2
2
95–297 °C; IR (KBr, cm ): 3130 (NH), 3057 (CHarom),
919 (CHaliph), 1676 (C=O), 1596 (C=N), 1319, 1170 (SO );
?
4
2
]; H-NMR (DMSO-d ): d
6
(ppm) : 10.1 (s, 1H, NH), 8.2 (s, 1H, H-6), 8.68–7.15 (m,
13
2
?
MS (m/z, %): 601 [M , 8.54 %], 587 [M –CH , 5.92 %,
3
17H, 4Ph), 3.38 (s, 2H, CH
0
2
); C-NMR (DMSO-d
6
): d
(ppm): 162.8 (C-9 ), 158.1 (C=O), 155.2 (C-3), 147.1 (C-
F ], 523 [F –SO , 1.52 %, F ], 431 [F –PhNH , 9.09 %,
2
1
1
2
2
2
F ],312 [F –PhNCO, 16.67 %, F ], 284 [F –N , 5.37 %, F ];
3
6), 141.5–118.2 (4Ph). Anal. Calcd for C32
692.6): C, 55.49; H, 2.91; N, 16.18.Found: C, 55.34; H,
2.80; N, 16.03.
H N O S
20 8 7 2
3
4
4
2
5
1
H-NMR (DMSO-d ): d (ppm) = 10.1 (s, 1H, NH), d 8.3 (s,
(
6
1
3
1
H, H-6) d 7.8–7.22 (m, 18H, 4Ph), d 2.9 (s, 3H, CH ); C-
3
0
NMR (DMSO-d ): d (ppm): 163.1 (C-9 ), 157.9 (C=O),
6
1
55.8 (C-3), 147.1 (C-6), 131.1–126.3 (4Ph), 18.1 (CH3).
0
0
Ethyl ((4-(8-oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno
2,3-c]pyridazin-7(8H)-yl)phenyl)sulfonyl) carbamate (12)
Anal. Calcd for C H N O S (601.7): C, 65.87; H, 3.85;
3 23 5 3 2
3
[
N, 11.64. Found: C, 65.72; H, 3.70; N, 11.50.
A mixture of 11a (1.0 g, 1.9 mmol), ethyl chloroformate
0 0
-(8-Oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyri-
4
(
(
0.21 g, 1.9 mmol), and anhydrous potassium carbonate
2.0 g) in dry acetone (100 mL) was refluxed for 5 h. The
dazin-7(8H)-yl)-N-(m-tolyl)benzene sulfonamide (11e)
solvent was removed under reduced pressure, the residue
was dissolved in water (100 mL) and neutralized with
acetic acid. The product separated out was filtered, washed
with water, dried, and recrystallized from ethanol to give
Yellow crystals from ethanol; yield 43.2 %, mp
-1
2
96–298 °C; IR (KBr, cm ): 3145 (NH), 3058 (CHarom),
2
915 (CHaliph), 1676 (C=O), 1596 (C=N), 1319, 1172 (SO );
2
?
MS (m/z, %): 602 [M ? 1, 1.80 %], 587 [M –CH ,
?
3
1
2. Yellow crystals, yield 70.1 %, mp 175–177 °C; IR
1
0
0
.99 %, F1], 495 [F –PhNH , 0.38 %, F ], 431 [F –SO ,
1
-1
KBr, cm ): 3350 (NH), 3059 (CHarom), 1721 (C=O,
2
2
2
2
(
.26 %, F ],313 [F –PhNCO, 1.90 %, F ], 285 [F –N ,
3
3
4
4
2
amide), 1670 (C=O, cyclic), 1600 (C=N), 1375, 1172
1
.17 %, F ]; H-NMR (DMSO-d ): d (ppm) = 10.3 (s, 1H,
?
SO ); MS (m/z, %): 583 [M , 27.20 %], 537 [M –
?
5
6
(
2
NH), d 8.2 (s, 1H, H-6) d 8.8 – 6.45 (m, 18H, 4Ph), d 2.85 (s,
CH CH OH, 36.40 %, F ],432 [F –SO NCO, 26.36 %,
3
1
3
0
2
1
1
2
3
1
2
6
H, CH3); C-NMR (DMSO-d ): d (ppm): 163.1 (C-9 ),
6
F ], 356 [F –Ph, 23.01 %, F ], 330 [F –N , 6.69 %, F ],
4
2
2
3
3
2
57.9 (C=O), 155.8 (C-3), 147.1 (C-6), 131.1–126.3 (4Ph),
1
2
87 [F –NCO, 22.59 %, F ]; H-NMR (DMSO-d ): d
4
5
6
2.3 (CH ). Anal. Calcd for C H N O S (601.7): C,
3 33 23 5 3 2
(
ppm) : 10.26 (s, 1H, NH), 8.7 (s, 1H, H-6), 7.7–7.2 (m,
13
4H, 3Ph), 3.3 (q, 2H, CH ), 2.07 (t, 3H, CH ); C-NMR
5.87; H, 3.85; N, 11.64. Found: C, 65.74; H, 3.75; N, 11.48.
1
2 3
0
(
(
(
DMSO-d ): d (ppm): 163.8 (C-9 ), 158.5 (2C=O), 156.2
6
0
0
N-Benzyl-4-(8-oxo-3,4-diphenylpyrimido[4 ,5 :4,5]
C-3), 148.1 (C-6), 140.5–121.2 (3Ph), 63.5 (CH ), 15.8
2
thieno[2,3-c]pyridazin-7(8H)-yl)benzene sulfonamide (11f)
CH ). Anal. Calcd for C H N O S (583.64): C, 59.68;
3 29 21 5 5 2
H, 3.63; N, 12.00. Found: C, 59.50; H, 3.47; N, 11.85.
Yellow crystals from ethanol; yield 35.9 %, mp
-1
2
2
90–292 °C; IR (KBr, cm ): 3155 (NH), 3058 (CHarom),
916 (CHaliph), 1677 (C=O), 1596 (C=N), 1318, 1173 (SO );
?
General procedure for the preparation of substituted 4-(8-
0
2
?
0
MS (m/z, %): 602 [M ? 1, 3.85 %], 537 [M –SO ,
2
oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno [2,3-c]pyridazin-
6
1
1
.24 %, F ], 447 [F –PhCH , 1.70 %, F ], 356 [F –PhNH ,
1
7 (8H)-yl)benzenesulfonylurea (13a–e)
1
2
2
2
2
.80 %, F ], 313 [F –NCO, 1.98 %, F ], 285 [F –N ,
3
3
4
4
2
1
4.14 %, F ]; H-NMR (DMSO-d ): d (ppm) = 10.5 (s, 1H,
To a solution of 12 (1.0 g, 1.7 mmol) in boiling toluene
(30 mL), the desired primary amines were added
(1.7 mmol) dropwise. The mixture was subsequently
refluxed for further 6 h, and the solvent was evaporated.
The residue was washed with diethyl ether and recrystal-
lized from ethanol.
5
6
NH), d 8.4 (s, 1H, H-6) d 7.68–7.35 (m, 19H, 4Ph), d 3.38 (s,
1
3
0
2
1
4
6
H, CH2); C-NMR (DMSO-d ): d (ppm): 163.1 (C-9 ),
6
57.9 (C=O), 155.8 (C-3), 147.1 (C-6), 141.5–126.9 (4Ph),
5.3 (CH ). Anal. Calcd for C H N O S (601.7): C,
2 33 23 5 3 2
5.87; H, 3.85; N, 11.64. Found: C, 65.77; H, 3.72; N, 11.50.
123

Med Chem Res
0
0
N-(Benzylcarbamoyl)-4-(8-oxo-3,4-diphenylpyrimido
0 0
4-(8-Oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyri-
dazin-7(8H)-yl)-N-(m-tolylcarbamoyl) benzenesulfonamide
(13d)
[
4 ,5 :4,5]thieno[2,3-c]pyridazin-7(8H)-
yl)benzenesulfonamide (13a)
Yellow crystals, yield 63.6 %, mp 177–179 °C; IR (KBr,
cm ): 3351, 3102 (2NH), 3055 (CHarom), 2923 (CHaliph),
Yellow crystals, yield 63.6 %, mp 130–132 °C; IR (KBr,
cm ): 3343, 3275 (2NH), 3056 (CHarom), 2980 (CHaliph),
-
1
-1
1
1
725 (cyclic C=O), 1646 (amide C=O), 1605 (C=N), 1333,
1720 (cyclic C=O), 1674 (amide C=O), 1602 (C=N), 1371,
?
140 (SO ); MS (m/z, %): 643 [M –1, 0.46 %], 581 [M –
?
?
1151 (SO ); MS (m/z, %): 644 [M , 7.51 %], 631 [M –
?
2
2
SO , 0.44 %, F ], 490 [F –PhCH , 0.66 %, F ], 431 [F –
2
CH , 5.20 %, F ], 554 [F –Ph, 7.80 %, F ], 496 [F –
2
2
1
1
2
2
3
1
1
2
1
NHCONH, 0.55 %, F ], 356 [F –Ph, 0.66 %, F ]; H-NMR
NHCONH, 0.19 %, F ], 355 [F –PhSO , 5.49 %, F ],330
3 3 2 4
3
3
4
1
(
DMSO-d ): d (ppm) : 10.2 (s, 2H, NHCONH), 8.4 (s, 1H,
[F –N , 5.0 %, F ]; H-NMR (DMSO-d ): d (ppm): 10.1 (s,
6
4
2
5
6
1
H-6), 8.1–7.23 (m, 19H, 3Ph), 4.3 (s, 2H, CH2); C-NMR
3
2H, NHCONH), 8.4 (s, 1H, H-6), 8.1–7.4 (m, 18H, 4Ph),
13
0
(
DMSO-d ): d (ppm): 163.2 (C-9 ), 161.8 (C=O, amide),
2.9 (s, 3H, CH3); C-NMR (DMSO-d ): d (ppm): 163.1
6
6
0
1
57.5 (C=O, cyclic), 156.9 (C-3), 147.1 (C-6), 140.5–126.2
(C-9 ), 161.0 (C=O, amide), 157.2 (C=O, cyclic), 156.3 (C-
(
(
4Ph), 45.5 (CH ). Anal. Calcd for C H N O S
2
3), 147.1 (C-6), 140.5–115.6 (4Ph), 26.5 (CH ). Anal.
3
34 24
6
4
2
644.72): C, 63.34; H, 3.75; N, 13.04.Found: C, 63.19; H,
.59; N, 12.88.
Calcd for C H N O S (644.7): C, 63.34; H, 3.75; N,
34 24 6 4 2
3
13.04. Found: C, 63.18; H, 3.60; N, 12.88.
N-((2-Chlorobenzyl)carbamoyl)-4-(8-oxo-3,4diphenylpy-
0
N-((4-Chlorophenyl)carbamoyl)-4-(8-oxo-3,4-diphenylpyri-
0
0
0
rimido[4 ,5 :4,5]thieno[2,3-c]pyridazin-7(8H)-
mido[4 ,5 :4,5]thieno[2,3-c]pyridazin-7(8H)-
yl)benzenesulfonamide (13b)
yl)benzenesulfonamide (13e)
Yellow crystals, yield 60.3 %, mp 168–170 °C; IR (KBr,
cm ): 3341, 3190 (2NH), 3057 (CHarom), 2981 (CHaliph),
Yellow crystals, yield 61.9 %, mp 115–117 °C; IR (KBr,
cm ): 3351, 3290 (2NH), 3056 (CHarom), 1720 (cyclic
-
1
-1
1
1
720 (cyclic C=O), 1675 (amide C=O), 1603 (C=N), 1366,
C=O), 1676 (amide C=O), 1596 (C=N), 1372, 1153 (SO );
2
?
149 (SO ); MS (m/z, %): 679 [M , 20 %], 567 [M –
?
?
?
MS (m/z, %): 665 [M , 0.14 %], 553 [M –C H Cl,
6 4
2
PhCl, 13.84 %, F ], 511 [F –CH NCO, 13.84 %, F ], 431
1
0.19 %, F ], 495 [F –NHCONH, 0.31 %, F ], 432 [F –
1 1 2 2
1
3
2
1
F –SO NH , 5.25 %, F ], 404 [F –N , 10.26 %, F ]; H-
[
SO , 0.18 %, F ], 315 [F –PhNCO, 0.88 %, F ], 287 [F –
2 3 3 4 4
2
2
2
3
3
2
4
1
NMR (DMSO-d ): d (ppm): 10.2 (s, 2H, NHCONH), 8.4
N , 5.83 %, F ]; H-NMR (DMSO-d ): d (ppm): 10.6 (s,
6
2
5
6
1
s, 1H, H-6), 8.1–7.23 (m, 18H, 4Ph), 4.5 (s, 2H, CH2); C-
3
(
2H, NHCONH), 8.5 (s, 1H, H-6), 8.4–7.4 (m, 18H, 4Ph);
13
0
0
NMR (DMSO-d ): d (ppm): 163.2 (C-9 ), 161.4 (C=O,
C-NMR (DMSO-d ): d (ppm): 163.1 (C-9 ), 161.0 (C=O,
6
6
amide), 157.1 (C=O, cyclic), 156.9 (C-3), 147.1 (C-6),
amide), 157.2 (C=O, cyclic), 156.3 (C-3), 147.1 (C-6),
140.5–120.6 (4Ph). Anal. Calcd for C H ClN O S
6 4 2
1
42.5–126.6 (4Ph), 43.5 (CH2). Anal. Calcd for
33
21
C H ClN O S (679.17): C, 60.13; H, 5.22; N, 12.37.
6 4 2
(665.1): C, 59.59; H, 3.18; N, 12.63. Found: C, 59.41; H,
3.01; N, 12.50.
3
4
23
Found: C, 60.00; H, 3.25; N, 12.20.
0
0
4
-(8-Oxo-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-c]pyri-
dazin-7(8H)-yl)-N-(o-tolylcarbamoyl) benzenesulfonamide
13c)
Results and discussion
(
The condensation of ethyl 5-amino-3,4-diphenylthieno[2,3-
c]pyridazine-6-carboxylate 1 with triethyl orthoformate in
the presence of acetic anhydride as a catalyst give the
corresponding ethoxymethyleneamino intermediate 2. This
was reacted directly without purification. The intermediate
2 was allowed to react with ammonium hydroxide at 70 °C
affording the 3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
c]pyridazin-8(7H)-one 3 in a good yield. The structure of
compound 3 was proved by its infrared, mass spectrum,
and elemental analysis. The IR spectrum showed absorp-
Yellow crystals, yield 54.5 %, mp 125–127 °C; IR (KBr,
cm ): 3344, 3280 (2NH), 3057 (CHarom), 2980 (CHaliph),
-
1
1
1
720 (cyclic C=O), 1674 (amide C=O), 1599 (C=N), 1372,
?
?
151 (SO ); MS (m/z, %): 644 [M , 30.0 %], 630 [M –
2
CH , 28.5 %, F ], 554 [F –Ph, 33.0 %, F ], 431 [F –
3
1
1
2
2
0
0
SO NHCONH, 43.0 %, F ], 315 [F –PhNCO, 32.5 %, F ];
4
2
3
3
1
H-NMR (DMSO-d ): d (ppm): 10.1 (s, 2H, NHCONH), d
6
8
.4 (s, 1H, H-6) d 8.1–7.4 (m, 18H, 4Ph),d 3.2 (s, 3H, CH );
3
1
3
0
C-NMR (DMSO-d ): d (ppm): 163.1 (C-9 ), 161.0 (C=O,
6
-
1
amide), 157.2 (C=O, cyclic), 156.3 (C-3), 147.1 (C-6),
40.5–115.6 (4Ph), 18.5 (CH3). Anal. Calcd for
C H N O S (644.7): C, 63.34; H, 3.75; N, 13.04. Found:
tion bands at 3,165 cm
corresponding to NH,
-
1,655 cm corresponding to C=O.
1
1
Heating compound 3 with phosphoryl chloride gave the
corresponding 8-chloro derivative 4 in a good yield. Its
3
4 24 6 4 2
C, 63.20; H, 3.62; N, 12.90.
1
23

Med Chem Res
structure was proved by elemental analysis and spectral
-
data, IR spectrum showed absorption band at 1,604 cm
based on an analytical and spectral data. The IR spectrum
-1
1
showed the presence of NH group at 3,414 and 3,150 cm ,
2
-
1
-1
-1
corresponding to C=N, 1,071 cm corresponding to C–Cl,
and there are no absorption bands in the carbonyl region.
Reaction of 8-chloro derivative 4 with sodium azide in
ethanol at refluxing temperature afforded 7,8-diphenyltet-
carbonyl group at 1,676 cm , and C=N at 1,594 cm .
Mechanistically, the formation of tricyclic compound 7
from 2 and hydrazine hydrate in involved the initial formation
of acid hydrazide which undergoes immediate intramole-
cular nucleophilic attack with elimination of ethanol mole-
cule, forms 1,2,4-triazepine derivative I, which, as a result
of transfer of the hydrogen atom from NH group to the oxygen
atom, forms a hybrid II. The hybrid, following a translocation
of the hydrogen atom from the nitrogen atom at position 3,
changes into a transient structure III, whereas at position 3, an
electron is still present as a result of hydrogen bond-
ing accompanying the nonbonding pair of electrons of the
nitrogen atom. That strongly electronegative nitrogen atom,
in the reaction of intermolecular nucleophilic rearrange-
ment, forms a link with the carbonyl carbon atom, releasing
the C–N bond. Structure IV, formed as result of that rear-
rangement, is not stable and, after translocation of the
hydrogen atom from the carbonyl oxygen atom, transforms
into compound 7 which is the product of this reaction chain
(Scheme 2).
0
0
00
0
0
0
0
razolo[1 ,5 :1 ,6 ]pyrimido[4 ,5 :4,5]thieno[2,3-c]pyrida-
zine 4, wherein 8-azido derivative was formed at the first
step, then intramolecular cyclization to the tetrazolo
derivative 4 occurred immediately. The predominant
existence of the tetrazolo derivative 5 was supported by
infrared spectral data, which exhibited no absorption bands
-
1
around 2,200 cm
due to azido group, and there is
-
1
absorption bands at 1,635 cm corresponding to C=N.
The 8-chloro derivative 4 on treatment with thiourea in
absolute ethanol gave thiouronium salt which on hydrolysis
with 2.5 N sodium hydroxide followed by acidification
with hydrochloric acid (pH 2) gave 3,4-diphenylpyrimido
0 0
[
4 ,5 :4,5]thieno[2,3-c]pyridazine-8(7H)-thione 6 in 48 %
yield. Structure of compound 6 was confirmed by its ele-
mental analysis and spectral data. The IR spectrum showed
1
-
absorption bands at 3,390 cm
-
corresponding to NH,
-1
1
1
,665 cm
corresponding to C=N, 1,531 cm
-
sponding to C=C and 1,194 cm corresponding to C=S
corre-
Alternatively, compound 7 was obtained upon heating of
5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carbohy-
drazide in dimethyl formamide as previously reported
(Deeb and El-Abbasy, 2006). Then, condensation of
7-amino derivative 7 with aromatic aldehydes namely
benzaldehyde, p-methoxybenzadehyde, and p-nitrobenzal-
dehyde was carried out in (1:1) molar ratio with
1
(
Scheme 1).
When the ethoxymethyleneamino derivative 2 was heated
with hydrazine hydrate in acetic acid at refluxing temperature,
0
0
afforded 7-amino-3,4-diphenylpyrimido[4 ,5 :4,5]thieno[2,3-
c]pyridazin-8(7H)-one7. Theassignmentofstructureof7 was
Scheme 1 Synthesis of
derivatives 1, 2, 3, 4, 5, and 6.
Reagents and conditions
i CH(OEt)
NH OH, iii POCl
NaN /EtOH, v NH
EtOH, NaOH, and then HCl
3
/Ac
2
O/reflux, ii
/reflux, iv
CSNH
4
3
3
2
2
/
123

Med Chem Res
Scheme 2 .
-
1
elimination of water producing 7-arylideneamino deriva-
tives 8a–c. The structures of compounds 8a–c were sup-
ported by their elemental analysis and spectral data. IR
spectrum revealed the presence of absorption bands at
absorption bands at 1,597–1,596 cm
C=N.
corresponding to
The N’-(un)substituted 4-aminobenzenesulfonamides 10
were prepared using a previously described method (Vogel
et al, 1980). The nucleophilic substitution of the 4-amino
group of 10 with 5-ethoxymethyleneamino-6-carboxylate 2
yielded the corresponding 7-N-substituted pyrimido thien-
opyridazines 11a–g. The structure of the synthesized
-
1
-1
3
,056–3,054 cm due to CHarom, 1,687–1,665 cm cor-
-
1
responding to carbonyl group, and 1,630–1,620 cm cor-
responding to C=N, further more IR spectrum of compound
-
1
8b showed the presence of CH
-
OCH at 1,079 cm . Also, IR spectrum of compound 8c
at 2,990 cm
and
aliph
1
1
compounds was established on the basis of their IR, H-
3
-
1
showed the presence NO at 1,519, 1,437 cm
2
.
NMR, and mass spectral studies. The infrared spectra of
-
1
Since the primary amino group when is directly attached
to a nitrogen of the heteroaromatic nucleus, an N-diazo-
nium ion is generated as an intermediate which decom-
poses with ultimate deamination and formation of
dinitrogen monoxide (Doyle et al., 1974). It was of interest
that the reaction of 7-amino derivative 7 with nitrous acid
11a–g showed absorption bands at 3,390–3,115 cm
-
1
corresponding to NH groups, 3,062–3,054 cm
corre-
-
sponding to CHarom, 1,676–1,664 cm corresponding to
1
-
C=O, 1,592–1,566 cm corresponding to C=N and bands
1
-
at 1,337–1,324, and 1,170–1,134 cm corresponding to
1
the symmetrical and asymmetrical vibrations of the SO
1
group. The H-NMR spectrum of 11c showed signals at d
2
0
0
yields the anticipated 3,4-diphenylpyrimido[4 ,5 :4,5]thie-
no[2,3-c]pyridazin-8(7H)-one 3. Compound 3 was identi-
cal (mp, mixed mp, and superimposable IR) with an
authentic sample synthesized in this work from 5-ethoxy-
methyleneamino derivative 2 which underwent smooth
cyclization to 3 in the presence of ammonium hydroxide
(ppm) = 10.3 corresponding to (SO NH) and at d = 8.4
2
1
corresponding to (H-6). Furthermore, the H-NMR spec-
trum of 11f showed signals at d 10.5 corresponding to
(SO NH), at d = 8.4 corresponding to (H-6) and at
d = 3.38 corresponding to (CH ) (Scheme 4).
2
2
(
Scheme 3).
On the other hand, we have prepared the interesting
sulfonylurea derivatives starting from the 7-(4-sulfamoyl-
phenyl)pyrimidothienopyridazine 11a on treatment with
ethyl chloroformate in refluxing acetone containing anhy-
drous potassium carbonate yielded ethyl carbamate deriv-
ative 12. The resulting carbamate was subsequently
condensed with different substituted amines such as benzyl
amine, o-chlorobenzyl amine, o-toluidine, m-toluidine, and
p-chloroaniline to give novel benzene sulfonylurea
Upon treatment of 5-ethoxymethyleneamino derivative 2
with amines such as benzyl amine, o-chlorobenzyl amine,
tyramine, and phenylhydrazine, finally afforded 7-N-substi-
tuted pyrimidothienopyridazines 9a–d. The infrared spectra
of 9a–d revealed the presence of absorptionbands at 3425 due
-1
-1
to OH, 3,390 cm corresponding to NH, 3,060–3,058 cm
-1
corresponding to CHarom, 2,917–2,916 cm corresponding
-1
to CHaliph, 1,677–1,676 cm corresponding to C=O, and
1
23

Med Chem Res
Scheme 3 Synthesis of
derivatives 7 and 8a–c.
Reagents and conditions
2 2 2
i NH NH .H O/AcOH/reflux, ii
2
ArCHO/EtOH/reflux, iii HNO /
HCl
Scheme 4 Synthesis of
derivatives 9a–d and 11a–g.
Reagents and conditions i
R-NH
2
/AcOH/reflux, ii
ii H N
NHR
SO2
2
(
10a–g), AcOH/reflux
-
1
derivatives 13a–e. The structures of compound 12 as well
as the final products 13a–e were confirmed on the basis of
both analytical and spectroscopic data. The IR spectrum of
compound 12 showed absorption band at 3,350 cm
-
corresponding to NH group, 3,059 cm corresponding to
1
-
1
CHarom, 1,721 cm
corresponding to (cyclic C=O),
123

Med Chem Res
Scheme 5 Synthesis of derivatives 12 and 13a–e. Reagents and conditions i ClCOOEt/K
Table 1 Antimicrobial activity of some synthesized compounds
2
CO
3 2
/Acetone/reflux, ii RNH /Toluene/reflux
Compound
Micrococcus luteus
Staphylococcus aureus
Escherichia coli
Candida albicans
1
1
1
1
1
1
1
1
1a
1b
1c
1d
1e
1f
????
??
?
????
??
?
???
???
???
???
??
???
????
???
???
????
???
??
??
?
??
?
??
???
??
–
??
???
??
–
???
???
???
–
1g
1f
???
–
DMF
Sulfadoxine
Sulfadimidine
Nystatin
???
???
–
???
???
–
??
???
???
????
??
–
Values are mean inhibition zone (mm) of two replicates, 25–35 mm = ????, 18–24 mm = ???, 11–16 mm = ??, B10 mm = ?,
–
= negative inhibition
-
,670 cm corresponding to (amide C=O), 1,600 cm
1
-1
1
and CH , respectively. The IR spectra of compounds 13a–e
3
-
1
corresponding to C=N and absorption band at 1,375, and
showed absorption bands at 3,351–3,102 cm corre-
-1
sponding to NH groups, 3,057–3,055 cm corresponding
-
,172 cm corresponding to the symmetrical and asym-
1
1
1
metrical vibrations of the SO group. The H-NMR spec-
-1
to CHarom, 2,980–2,923 cm
-
corresponding to CHaliph
,
2
1
trum showed signals at d (ppm) = 10.26 corresponding to
1,725–1,720 cm
corresponding to (cyclic C=O),
-
1,674–1,646 cm corresponding to (amide C=O), 1,605-
1
(
SO NH), and at d = 3.3 and 2.07 corresponding to CH2
2
1
23

Med Chem Res
-
,599 cm corresponding to C=N, and absorption bands at
1
1
1
Bauer AW, Kirby MDK, Sherries JC, Turck M (1966) Antibiotic
susceptibility testing by standard single disc diffusion method.
Am J Clin Pathol 45:493–496
Butnariu RM, Caprosu MD, Bejan V, Mangalagiu II, Ungureanu M, Poiata
A, Tuchilus C, Florescu M (2007) Pyridazine and phthalazine
derivatives with potential antimicrobial activity. J Hetrocycl Chem
-
,372–1,333 and 1,151–1,140 cm corresponding to the
1
symmetrical and asymmetrical vibrations of the SO2
groups (Scheme 5).
44(5):1149–1152
Chambhare RV, Khadse BG, Bobde AS (2003) Synthesis and
preliminary evaluation of some N-[5-(2-furanyl)-2-methyl-4-
oxo-4H-thieno[2,3-d]pyrimidin-3-yl]-carboxamide and 3-substi-
tuted-5-(2-furanyl)-2-methyl-3H-thieno[2,3-d]pyrimidin-4-ones
as antimicrobial agents. Euro J Med Chem 38(1):89–100
Connor EE (1998) Sulfonamide Antibiotics. Prim Care Update Ob
Gyns 5(1):32–35
Antimicrobial activity
Applying the agar plate diffusion technique (Bauer et al.,
1
966), the newly synthesized sulfonamide derivatives were
screened in vitro for antimicrobial activity against Gram-
positive bacteria (S. aureus and M. luteus), Gram-negative
bacteria (E. coli), and fungi (C. albicans). In this method, a
standard 5 mm diameter sterilized filter paper dis impreg-
nated with the compounds (400 l/0.1 mL of dimethyl-
formamide) was placed on the agar plates which had
previously been inoculated with the above organisms. The
petri dishes were left at 4 °C for 2 h.; then the injected
plates with bacteria were incubated at 37 ± 0.1 °C for
Deeb A, El-Abbasy M (2006) Pyridazine derivatives and related
compounds, part 20:1 synthesis of different heterocycles from
5-Aminothieno[2,3-c]pyridazine-6-carbohydrazide. Phosphorus
Sulfur Silicon 181:397–404
Deeb A, Said SA, Hamed MM, Yasin F (1990) Pyridazine derivatives and
related compounds, part 1. Some reactions with 4-cyano-5,6-
diphenyl-2,3-dihydropyridazine-3-one. J Chin Chem Soc 37:287–294
Deeb A, El-Eraky W, El-Awdan S, Mahgoub S (2014) Pyridazine and
its related compounds, Part 34: hypoglycemic and hypolipidemic
activity of some novel condensed pyridazine sulfonamides. Med
Chem Res 23:34–41
2
4 h., and those inoculated with fungi incubated at
2
5 ± 0.1 °C for 48 h. At the end of the period, diameter of
inhibition zones was measured in mm; these studies were
Doyle MP, Kalmbacher JG, Wierenga W, Deboer JE (1974)
Nitrosative cleavage of benzalazine and related aldehyde azines.
Production, decomposition and trapping of iminodiazonium ions.
Tetrahedron Lett 15(15):1455–1458
performed in two replicates. The screening results given in
(
Table 1) indicated that all the compounds exhibited anti-
Drochioiu G, Sunel V, Oniscu C, Basu C, Murariu M (2007) The
breakdown of plant biostructure followed by amino acids
determination. Rom Biotechnol Lett 6(2):155–165
microbial activity against all the test organisms.
Han X, Hong YH, You Quan ZHU, Mao LIU, Bim ZX, Fang Zhong
HU, Zheng YH (2010) Synthesis and herbicidal activities of
novel 4-(3-trifluoromethylphenyl)-2H-pyridazin-3-one deriva-
tives. Sci China Chem 53(1):157–166
Conclusion
Hansch C, Sammes PG, Taylor JB (1990) Comprehensive medicinal
chemistry. Pergamon Press, Oxford, pp 255–270
Hanson PR, Probst DA, Robinson RE, Yau M (1999) Cyclic
sulfonamides via the ring-closing metathesis reaction. Tetrahe-
dron Lett 40:4761–4764
Kandile NG, Mohamed MI, Zaky H, Mohamed HM (2009) Novel
pyridazine derivatives: synthesis and antimicrobial activity
evaluation. Eur J Med Chem 44(5):1989–1996
Kleemann A, Engel J, Kutscher B, Reichert D (1999) Pharmaceutical
substance: syntheses, patents, applications, 2nd edn. Thieme, Stuttgart
Mangalagiu II (2011) Recent achievements in the chemistry of 1,2-
diazines. Curr Org Chem 15(5):730–752
In summary, we have developed and synthesized novel
derivatives of pyrimidothienopyridazine. Some of the tar-
get compounds bearing the sulfonamide group were eval-
uated for their antimicrobial activity, and the following was
concluded: derivative 11a has promising inhibitory activity
against Gram-positive bacteria. Derivatives 11b and 11e
have remarkable inhibitory activity against fungi. Rest of
the compounds showed moderate to low activity against
the examined micro-organisms.
Mantu D, Luca MC, Moldoveanu C, Zbancioc G, Mangalagiu II (2010)
Synthesis and antituberculosis activity of some new pyridazine
derivatives. Part II. Eur Med Chem 45(11):5164–5168
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123