A versatile synthesis, PM3-semiempirical, antibacterial, and antitumor evaluation of some bioactive pyrazoles

Article abstract of DOI:10.1002/jhet.806

This research work describes the synthesis and biological properties of some novel isolated or fused heterocyclic ring systems with pyrazole, for example; enaminones containing pyrazolone ring photochromic functional unit, 4-[(4-chlorophenylamino)methylene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (3) and some analogous derivatives 4, 9, and 10, also as pyrazolo[3,4-b]pyridine, pyrazolo[3,4-b]quinoline, pyrazolo[3',4':4,5]thieno[2,3-c]pyrazoline and pyrazolo[3,4-c]pyrazole were synthesized and characterized. Newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR, mass spectral data and quantum mechanical calculations. Selected products were tested for their antibacterial and antitumor agents.

Full text of DOI:10.1002/jhet.806

May 2012
A Versatile Synthesis, PM3-Semiempirical, Antibacterial, and
Antitumor Evaluation of Some Bioactive Pyrazoles
543
*
Wafaa S. Hamama, Hamada G. El-Gohary, Mamdouh Soliman,
and Hanfi H. Zoorob
Department of Chemistry, Faculty of Science, Mansoura University, ET-35516, Egypt
*
E-mail: wshamama@yahoo.com
Received August 8, 2010
DOI 10.1002/jhet.806
View this article online at wileyonlinelibrary.com.
This work describes the syntheses and biological activities of some novel isolated or fused heterocyclic
ring systems incorporated pyrazolone moiety, for example; enaminones containing pyrazolone ring photo-
chromic functional unit, 4-[(4-chlorophenylamino)methylene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one
(3) and some analogous derivatives 4, 9, and 10, also as pyrazolo[3,4-b]pyridine, pyrazolo[3,4-b]quinoline,
pyrazolo[30,40:4,5]thieno[2,3-c]pyrazoline and pyrazolo[3,4-c]pyrazole were synthesized and characterized.
Newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass spectral data and quantum
mechanical calculations. Selected products were tested for their antibacterial and antitumor agents.
J. Heterocyclic Chem., 49, 543 (2012).
INTRODUCTION
Pyrazoles are key structures in numerous compounds
of therapeutic importance [1]. Compounds containing
this ring system are known to display diverse pharmaco-
logical activities such as antibacterial, antifungal [2],
anti-inflammatory, analgesic [3], and antipyretic [3]. 3-
Alkyl-4-arylmethylpyrazol-5-ones are reported to exhibit
potent antihyperglycemic activity [4], 1-phenyl-3-tetra-
fluoroethylpyrazol-5-one is an anxiolytic [5] and 4,4-
dichloro-1-(2,4-dichlorophenyl)-3-methyl-5-pyrazolone as
a potent catalytic inhibitor of human telomerase [6],
telomerase is a large ribonucleoprotein complex of reverse
transcriptase enzyme, because it suppresses the telomerase
activity in tumor cells it can be an encouraging strategy
of anticancer therapy [7]. Pyrazoles are important
in treatment of ophthalmological diseases [8], dye
stuffs [9], and antidepressant activity [10]. The number
of investigations for organic photochromic materials has
increased considerably in recent years because of their
potential commercial applications in several areas, such
as high-density optical storage media, eye-protecting
glasses and optical switching devices [11]. So far, though
numerous organic photochromic molecular systems or
photoactive devices have been explored, these systems
which have been classified according to the photochromic
© 2012 HeteroCorporation

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W. S. Hamama, H. G. El-Gohary, M. Soliman, and H. H. Zoorob
Vol 49
structural units mainly belong to a small number of fami-
lies, such as spiropyrans, spiroxazine, diarylethenes,
Schiff bases [12], and pyrazolone derivatives [13]. Its
photochromic properties are due to intermolecular proton
transfer (PT) [14]. PT Reaction is central to several fields
of chemistry and biochemistry and plays a key role in
pharmaceutical action, enzyme activity and the stabiliza-
tion of base pairs in duplex DNA.
Schiff bases are an interesting class of compounds
possessing O—HꢀꢀꢀꢀꢀꢀN hydrogen bond and the PT reac-
tion can proceed through it. These compounds are often
thermo or photochromic behavior, undergoing revers-
ible PT in the solid state. However, until recently no
NH form had been structurally characterized [15].
Chemotherapeutically valuable compounds in this
class such as 4-(arylmethylene)-2,3-dihydropyrazol-3-ones
(as neoplastic lesion inhibitors) are reported as patent in
literature [16].
RESULTS AND DISCUSSION
In this study, enaminocarbonyl compounds containing
pyrazolone ring were synthesized, by reaction of 1-phe-
nyl-3-methylpyrazol-5-one (1) [17] with triethyl orthofor-
mate to give the intermediate 2, which transformed with
N-nucleophiles such as p-chloroaniline in n-butanol via ad-
dition-elimination mechanism to give 4-[(4-chlorophenyla-
mino)methylene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)one
(3) in good yield (Scheme 1).
The exact tautomeric form of compound 3 [Scheme 2
(a)] was established by the quantum mechanical calcula-
tions using the PM3 semiempirical molecular orbital
Scheme 1. Reactions involving active methylene group of 1-phenyl-3-methylpyrazol-5-one (1) with different reagents.
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A Versatile Synthesis, PM3-Semiempirical, Antibacterial, and
Antitumor Evaluation of Some Bioactive Pyrazoles
545
Scheme 2. Tautomeric forms of 4-[(4-chlorophenylamino)methylene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)one (3) and (E)-3-methyl-4-(methylthio
(phenylamino)methylene)-1-phenyl-1H-pyrazol-5(4H)-one (8).
method (Table 1), the tautomeric form A was found to
have the lower total energy.
respectively. The results of quantum mechanical molecular
orbital calculations using the PM3-semiempirical molecu-
lar quantum mechanical method (Table 1) indicated that
(Z) configuration was found to have the lower binding
energy than the (E) configuration which indicates the
global stability of the (Z) configuration (Fig. 1) as (4Z)-4-
[(4-chlorophenylamino)methylene]-3-methyl-1-phenyl-1H-
pyrazol-5(4H)one (3). The distance of H-bond in tautomer
The structure of 3 was established on the basis of its an-
alytical and spectral data. The IR spectrum showed bands
at 3419, 3061, and 592 cmꢁ1 corresponding to (NH),
1
(¼C—H) and (C—Cl) groups, respectively, its H NMR
spectrum exhibited three singlet signals at d 2.29, 7.61,
and 8.48 ppm due to methyl, methine and (NH) protons,
Table 1
Quantum mechanical data obtained from PM3-semiempirical MO calculations of the configurations of different compounds.
Cpd.
Configuration
Total energy (Kcal/mol)
Binding energy (Kcal/mol)
Twist angle (ꢂ)
Dipole moment (Debye)
3
Z, Aa
Ba
ꢁ76677.5
ꢁ76674.2
ꢁ76672.3
ꢁ76670.2
ꢁ120938.7
ꢁ120935.8
ꢁ120936.0
ꢁ92203.7
ꢁ92204.3
ꢁ77455.1
ꢁ77452.13
ꢁ77455.46
ꢁ77455.95
ꢁ159982.2
ꢁ159981.5
ꢁ159981.8
ꢁ113505.1
ꢁ113507.2
ꢁ88744.1
ꢁ88745.3
ꢁ4005.1
ꢁ4002.0
ꢁ3999.9
ꢁ3997.8
ꢁ6727.7
ꢁ6724.8
ꢁ6725.0
ꢁ5026.3
ꢁ5027.2
ꢁ4351.2
ꢁ4348.3
ꢁ4351.7
ꢁ4352.1
ꢁ9233.3
ꢁ9232.6
ꢁ9232.8
ꢁ6380.1
ꢁ6382.5
ꢁ4735.0
ꢁ4736.2
5.0
44
176
5.0
3.3
179.5
178, 178
0.0
4.02
1.6
3.42
1.6
E, Ca
Da
4
Z, Z
E, Z
E, E
Z
1.07
3.75
1.14
2.83
1.90
4.57
1.94
3.37
4.18
2.86
5.66
3.14
1.76
3.07
2.85
6
8
E
178
E, Aa
E, Ba
Cb
178.8
101.3
89.7
122.7
4.1
174.8
176, 175
4.0
E, Da
Z, Z
E, Z
E, E
Z
9
10
18
E
Z
E
171
10
179
aTautomeric forms.
bPerpendicular to each other [angle nearly 90ꢂ].
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Figure 1. Optimum geometries of (a) compound 3 and (b) compound 4.
A is 2.4 Å (HꢀꢀꢀꢀꢀꢀꢀO) stronger than that of tautomer B, 2.5 Å
(HꢀꢀꢀꢀꢀꢀꢀꢀN).
The UV spectra were observed to be complicated and com-
posed of different overlapped absorption peaks in this
range of wavelengths. The different peaks in this range
were subjected to Gaussian analysis followed by least
square fitting to detect the individual peaks in each spectra
using PKFIT Ver 2.0 software. The analyzed spectra were
found to compose of the absorption peaks in (Table 2).
From these data it was found that, both compounds 3
and 4 have good optical absorption characters, but com-
pound 4 was better than 3 due to its high proton transfer
ability.
Because of the enhanced biological activity of pyrimi-
dine moiety [20], it was of interest to introduce a substitu-
ent at position 5 of this moiety, whereby a highly
conjugated derivative 5 can be synthesized. Treatment of
1 with triethylorthoformate and 6-aminothioruacil or gly-
cine afforded methylidene-dipyrazolinone 6. Alternatively,
the structure 6 was also formed via intermolecular conden-
sation of intermediate 2 by heating with another molecule
of 1. The structure of 6 was proved by its identical melting
point with that reported in literatures [21] besides its IR
and mass spectra which showed the molecular ion peak
at m/z 358 (M+) as a base peak.
A considerable number of bis-heterocyclic compounds
exhibited various biological activities including antibacte-
rial, fungicidal, tuberculostatic and plant growth regulative
properties [18]. Also, it was reported that bis-heterocyclic
compounds display much better antibacterial activity than
mono-hetrocyclic compounds [19]. These observation pro-
moted us to synthesize the 1,4-bis(3-methyl-1-phenyl-
(4Z)-4-methyleneamino-1H-pyrazolo-5-(4H)-one)benzene
(4) as bis-enamino containing bis-pyrazolone ring by reac-
tion of 1 with p-phenylenediamine. Its constitution was
supported by elemental analysis, IR, 1H NMR and ms
spectra. The mass spectrum gave a molecular ion peak at
m/z 476 (M+, 33%). The results of quantum mechanical
molecular orbital calculations (Table 1) indicated that the
(Z,Z) configuration was found to have the lower binding
energy than (E,Z) configuration or (E,E) configuration
which indicates the global stability of the (Z,Z) configura-
tion [Fig. 1(b)] as 1,4-bis(3-methyl-1-phenyl-(4Z)-4-
methyleneamino-1H-pyrazolo-5-(4H)-one)benzene (4).
The UV-spectra of compounds 3 and 4 were measured in
the range from 200 to 450 nm for 3 and to 500 nm for 4.
Table 2
Influence of DMF on lmax (nm) of compounds 3 and 4.
Compound No.
Wavelength lmax (nm)
Absorbance
Log E
Wavelength lmax (nm)
Absorbance
Log E
3
219
235
247
264
299
218
229
244
254
270
342
364
376
0.316
0.211
0.123
0.413
0.009
0.319
0.279
0.138
0.192
0.257
0.167
0.087
0.152
4.13
3.96
3.72
4.25
2.59
4.60
4.54
4.24
4.38
4.51
4.32
4.04
4.28
344
364
378
392
415
390
410
433
442
454
468
482
0.653
0.087
0.179
0.180
0.204
0.097
0.307
0.093
0.087
0.111
0.046
0.085
4.45
3.57
3.89
3.89
3.94
4.08
4.59
4.07
4.04
4.14
3.76
4.03
4
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A Versatile Synthesis, PM3-Semiempirical, Antibacterial, and
Antitumor Evaluation of Some Bioactive Pyrazoles
547
Figure 2. Optimum geometries of (a) compound 6 and (b) compound 10.
The results of quantum mechanical molecular orbital
calculations (Table 1) indicated that the (E) configuration
was found to have the lower binding energy than the (Z)
configuration which indicates the global stability of the
(E) configuration. (4E)-4-[(4,5-dihydro-3-methyl-5-oxo-1-
phenyl-1H-pyrazol-4-yl)methylene]-3-methyl-1-phenyl-1H-
pyrazol-5(4H)-one (6) [Fig. 2(a)].
Furthermore, a diamine fragment is incorporated into
the heterocyclic core of a variety of drug classes (e.g.,
cardizem as calcium channel blocker, ciprofloxacin as anti-
bacterial and clozapine as antipsychotic) were reported in
literature [22]. Also, piperazinyl derivatives were reported
as antipsychotic agents [23]. This persuaded us to synthe-
size compound 9 through the reaction of the pyrazolone
derivative 1 with phenylisothiocyanate in the presence of
sodium hydride a strong base followed by methylation
with methyl iodide to afford the thiocarbamoyl 8 [24].
Compound 8 was fused with secondary amines namely;
piperazine or ethyl piperidine-4-carboxylate to afford the
corresponding bis-N-pyridyl and N-pyridyl 9 and 10,
respectively (Scheme 1). Its structure was confirmed by
elemental analysis, IR, 1H NMR and mass spectra.
The exact tautomeric form of compound 8 [Scheme 2
(b)] was established by the quantum mechanical calcula-
tions using the PM3 semi-empirical molecular orbital
method (Table 1), the tautomeric forms A, B and D were
the tautomeric form A, C and D was found in equilibrium
at room temperature since the difference in binding energy
between them does not exceed 1K cal/mol.
The results of quantum mechanical molecular orbital
calculations (Table 1) indicated that the (Z,Z) configuration
was found to have the lower binding energy than the (E,Z)
configuration and (E,E) configuration which indicates the
global stability of the (Z,Z) configuration as 1,4-bis(3-
methyl-1-phenyl-(4Z)-4-methylenylanilino-1H-pyrazolo-5-
(4H)-one)piperazine (9) (Fig. 3).
The replacement of the (S-Me) group with amines has
been reported [25]. 1,4-Dihydropyridine systems show ex-
ceptional properties as calcium antagonists, as powerful ar-
teriolar vasodilators and also as inhibitors of dihydrofolate
reductase [26], This enthused us to replace the (S-Me)
Figure 3. Optimum geometry of compound 9.
group of compound 8 with ethyl isonipicotate to give com-
pound 10 (Scheme 1). Its constitution was proved by its IR,
1H NMR and mass spectra. The results of quantum me-
chanical molecular orbital calculations (Table 1) indicated
that the (E) configuration was found to have the lower
binding energy than the (Z) configuration, which indicates
the global stability of the (E) configuration as ethyl(3-
methyl-1-phenyl-(4E)-4-metylenylanilino-1H-pyrazolo-5-
(4H)-one) piperidine-4-carboxylate (10) [Fig. 2(b)].
Ketonic Mannich bases are b-bifunctional reactive
synthons. These compounds have been widely used as
good alkylating agents [27]. C-alkylation reaction of
ketonic Mannich bases w\ith active hydrogen derivatives
has been reported [28]. Accordingly, the reaction of
phenylalkanone Mannich base hydrochloride 11 with 1 in
aqueous methanol gave 1,5-diketone 12. It was character-
ized by spectral data and elemental analyses. The IR spec-
trum of 12 exhibited bands at 1738 and 1686 cmꢁ1 for
1
(C¼O) and (O¼C—N—Ph) groups. The H NMR spec-
trum showed a singlet signal at d 2.04 of (CH3—C¼N),
quartet at d 2.25 of (CH2—CH2CO, J = 4.0 Hz), triplet,
at d 2.75 of (CH2—CH2CO, J = 4.0 Hz), triplet at d 3.34
of (CHCH2CH2CO, J = 4.0 Hz) and multiplet at d 7.20–
8.00 ppm for aromatic protons. The mass spectrum showed
the molecular ion peak at m/z 306 (28%).
Compound 12 can be used as a key intermediate for the
construction of 3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b]
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pyridine (14) through the reaction of 12 with (NH4)2CO3 in
presence of acetic acid. Formulation of structure 14 was
based on elemental analysis, IR and mass spectra which
showed the molecular ion peak at m/z 285 (5%).
cyanoacetamide in methanol containing triethylamine,
the pyridine derivative 23 was the isolated product. The
probable mechanism for the formation of the pyridine
derivative 23 is that the 4-(4-methoxybenzylidene)
pyrazolinone 19 undergoes Michael condensation with
one mole of cyanoacetamide to give a Michael adduct
20 which eject p-methoxybenzylidine cyanoacetamide
molecule. The later compound was then condensed with
another cyanoacetamide molecule with subsequent loss
of water to afford the pyridine derivative 23 (Scheme 4).
Moreover, compound 23 was isolated in good yield by
the reaction of p-methoxybenzaldehyde with cyanoaceta-
mide (1:1) molar ratio in methanol catalyzed by triethyla-
mine. When this reaction was carried out in a (1:2) molar
ratio the same product was obtained with higher yield.
The structure 23 was ascertained by elemental analysis,
IR, 1H NMR, and mass spectra as well as its identical melt-
ing point with that reported in literature [32]. The forma-
tion of pyridine derivative 23 is in accordance with the
mechanistic proposal in literature [33].
Carticaine [29] and carticaine analogues [30] were
proved to be local anesthetics and antiarrhythmic agents.
Therefore, the thiophene ring of carticaine was replaced
by the pyrazolone moiety to prepare a carticaine analogue
in an attempt to assess and enhance its biological activity.
Therefore, attempted synthesis of the target compound 16
according to the Gewald method in our previous work
[26] by reaction of 1 with ethyl cyanoacetate and sulfur
in the presence of triethylamine, was unsuccessful. Instead
of tricyclic system, 3,7-dimethyl-1,5-diphenyl-1H,5H-
pyrazolo[30,40:4,5]thieno[2,3-c]pyrazoline (15) was unequiv-
ocally obtained. The constitution of 15 was ascertained by its
IR, 1H NMR and mass spectra which showed the molecular
ion peak at m/z 344 [M+].
The synthetic potentialities of 1,2-diketone promoted us
to oxidize 1 by selenium oxide to obtain 17 but the conden-
sation product 18 was isolated as a sole product instead of
of 17 (Scheme 3). Compatible analytical and spectroscopic
evidences were gained for structure 18. Accordingly, its 1H
NMR spectrum showed a singlet signal at d 2.15 due to
two methyl groups and multiplet at d 7.16–7.90 ppm for
aromatic protons.
Substituted bicyclic pyrazolones were used as inhibitors
of tumor necrosis factor-a-(TNF-a) production [34]. Also,
a,b-unsaturated ketones were used as synthons to construct
different heterocycles [35]. Therefore, when a mixture of 19
and nicotinic hydrazide was refluxed in methanol catalyzed
by triethylamine, 2,3-dihydro-3-(4-methoxyphenyl)-4-
methyl-6-phenyl-pyrazolo[3,4-c]pyrazol-1(2H)-yl)(pyridin-4-
yl)methanone (24) was obtained. The product was
On the other hand, investigation of the reaction of
4-(4-methoxy-benzylidene) pyrazolinone (19) [31] with
Scheme 3. Synthesis of pyrazolo[3,4-b]pyridine (14), thieno[3,2-c]pyrazole-6-carboxylate (15), and bis-pyrazolone (18) derivatives.
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Antitumor Evaluation of Some Bioactive Pyrazoles
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Scheme 4. Synthesis of 6-amino-4-(4-methoxyphenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile (23) and (3-(4-methoxyphenyl)-4-methyl-6-phenyl-
2,3-dihydropyrazolo[3,4-c]pyrazol-1(6H)-yl) (pyridin-4-yl)methanone (24).
characterized by its spectroscopic and analytical data. The 1H
NMR spectrum exhibited characteristic singlet signals at d
8.41 and 8.79 ppm for the methine and amino protons,
respectively. The mass spectrum showed the molecular ion
peak at m/z 411 (M+, 5%).
Pyrazolopyridopyrimidine derivatives are reported as
antimicrobial [36], potent and selective PDE5 inhibitors
[37]. In view of these reports and as continuation of our
recent studies [38], persuaded us to synthesize compounds
27 and 29 via cycloaddition of 4-(4-methoxybenzylidene)
pyrazolinone derivative 19 with 6-amino-thiouracil (25)
in ethanol and acetic acid mixture to afford 27 and with
6-amino-1,3-dimethyluracil (26) in acetic acid to afford
29 through auto-oxidation (Scheme 5). The products 27
and 29 were characterized by their elemental analysis and
spectral data (ir, 1H NMR and mass spectra). The 1H
NMR spectrum of 27 displayed a singlet signal at d 2.50
ppm corresponding to methyl protons, doublets at d 2.69
and 2.85 ppm due to (CH—CO, J = 12.8 Hz) and (CH, J
= 12.8 Hz), respectively, and other three singlet signals at
d 3.69, 5.28, and 7.93 ppm due to (OCH3), (NH), and
(NH), (NH, exchangeable with D2O), respectively.
Attempting to synthesize the bis(pyrazolopyridino)benzene
derivative 30 by reaction of 19 with p-phenylenediamine
in ethylene glycol at 180ꢂC was unsuccessful and com-
pound 32 was formed instead of 30. Compound 32 was
achieved through the oxidation effect upon the intermediate
4-anisylidine-5-aryliminopyrazoline derivative 31, formed
from condensation of 19 with p-phenylenediamine (Scheme
5). The mechanism of this reaction is in line with those
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Scheme 5. Reactions of arylidine derivative 19 with different amines.
Antitumor studies.
The standard method used to
reported in literature [39]. The constitution of 32 was proved
separate, identify, and purify DNA fragments is
electrophoresis [40] through agarose gels, the technique
is simple, rapid to perform, and capable of resolving
mixtures of DNA fragments that cannot be separated
adequately by other sizing procedures, such as density
gradient centrifugation. Furthermore, the location of
DNA within the gel can be determined directly bands of
DNA in the gel are stained with low concentration of the
fluorescent dye, ethidium bromide. The method used to
detect strand breakage is based up on the different tail
mobility of different forms of bacterial DNA.
Compounds 3, 4, 10, 15, 27 and 29 have strong
degredative effect on DNA while other compounds has
slight effect on DNA, these effect may be attributed to
the hydrolysis of glycosidic bond in DNA. The
hydrolytic effect of these compounds on the DNA may
be useful in treatment and these compounds can be used
as antitumor agents after some in vitro studies.
by IR, mass spectrum and elemental analysis.
Antibacterial activity.
The antibacterial activity
evaluated by using agar plate method. In this method E.
coli (Gram -ve) and B. subtillias (Gram +ve) were used
as test organism and Ampicillin was used as reference
drug. The results of antibacterial activities of some
synthesized compounds were shown in Table 3. Test
solutions of these compounds were tested at
concentration of 100 ppm. It should be mentioned that
both DMF and DMSO did not show any inhibition on
bacterial growth. Based on the diameter of inhibition
zones, the antibacterial activity of the tested compound
on the growth of E. coli and B. subtillias can be ranked
descending as compounds 10 > 18 > 27 > 29 = 14 = 3
= 9 = 4 =12 > 15 = 24 = 6 = 32 > 23. This finding may
suggest the possible use of the compounds that showed
antibacterial activity in the field of chemotherapy as
antimicrobial agents.
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Antitumor Evaluation of Some Bioactive Pyrazoles
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Table 3
spectrometer V3.32. Follow-up of the reactions and checking
the homogeneity of the compounds were monitored by thin layer
chromatography (TLC) using EM science silica gel coated plates
with visualization by irradiation with ultraviolet lamp l 254 nm.
(Z)-3-Methyl-4-(methylthio(phenylamino) methylene)-1-phenyl-
1H-pyrazol-5(4H)-one (8) and 4-(4-methoxybenzyl)-3-methyl-1-
phenyl-1H-pyrazol-5(4H)-one (33) were reported previously in
the literature [24,39].
Diameter of inhibition zone in mm as a criterion of antibacterial activity of
some synthesized compounds at concentration 100 ppm.
Inhibition zone (mm)
Gram positive
bacteria Bacillus
Compound
No.
Gram negative bacteria
Escherichia coli
subtilis
Synthesis of enaminopyrazolones 3, 4 and 6. To a warm
solution of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (1) (0.5 g,
2.87 mmol) in n-butanol (15 mL), triethylorthoformate (0.48
mL, 2.87 mmol) was added drop wise with stirring, then added
4-chloroaniline (0.37 g, 2.87 mmol), p-phenylenediamine (0.31
g, 2.87 mmol) or 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (0.5
g, 2.87 mmol). The reaction mixture was heated at 100ꢂC for 1
h and for 2 h in case of reaction with 3-methyl-1-phenyl-1H-
pyrazol-5(4H)-one, left to cool, the formed precipitate was
collected by filtration and recrystallized from methanol to afford
3, 4 and 6, respectively.
10
18
27
29
14
3
9
4
12
15
24
6
32
23
36
30
25
22
22
22
22
20
20
17
16
15
14
12
19
40
35
30
28
27
27
25
24
23
23
22
20
18
14
21
(4Z)-4-[(4-Chorophenylamino)methylene]-3-methyl-1-phenyl-
1H-pyrazol-5(4H)one (3).
(85%), mp 143–145ꢂC; yellow
crystals; UV-vis spectral measurements: solvent (DMF),
concentration, (2.33 ꢃ 10ꢁ5M): lmax = 219, 235, 247, 264,
299, 344, 364, 378, 392, 415; IR (KBr) ׳υ (cmꢁ1), 3419, 3061,
2980, 2914, 1672, 1625, 1588, 1004, 753, 592; 1H NMR
(200 MHz, DMSO-d6): d, 2.29 (s, 3H), 7.10–7.52 (m, 5H), 7.61
(s, 1H), 7.63 (d, J = 8.4 Hz, 2H), 7.99 (d, J = 8.4 Hz, 2H), 8.48
(s, 1H); ms: (m/z, %): 313 (M+ +2, 4), 312 (M++1, 3), 311
(M+, 12), 185 (33), 128 (5), 126 (14), 109 (16), 56 (26), 57
(100). Anal. Calcd. for C17H14ClN3O (311.77): C 65.49,
H 4.53%. Found: C 65.57, H 4.59%.
Ampicillin
CONCLUSION
Fourteen novel compounds incorporated pyrazolone or
pyrazole moieties were synthesized and characterized by
elemental analyses and spectral data. The compounds char-
acterization was extended to include the quantum mechan-
ical molecular orbital calculations (Table 1) for compounds
3, 4, 6, 8, 9, 10 and 18. Compounds 3 and 8 have four
tautomer structures A-D in which the most stable structure
is tautomer A in both cases due to the H-bond formation
and in view of the less energy structures and also other
ene compounds were also studied. The tested compounds
were screened for their antibacterial and antitumor activi-
ties. The tested compounds exhibited in high antibacterial
activity activities also, compounds 3, 4, 10, 15, 27 and 29
have strong degredative effect on DNA.
1,4-Bis(3-methyl-1-phenyl-(4Z)-4-methyleneamino-1H-
pyrazolo-5-(4H)-one)benzene (4).
(87%) mp 240ꢂC;
orange-yellow crystals; UV-vis spectral measurements:
solvent (DMF), concentration (7.98 ꢃ 10ꢁ6M): lmax = 218,
229, 244, 254, 270, 342, 364, 376, 390, 410, 433, 442, 454,
468, 482; IR (KBr) ׳υ (cmꢁ1), 3416, 3330, 3044, 2916,
1664, 1623, 1593, 1003, 753; 1H NMR (200 MHz, DMSO-
d6): d, 2.25 (s, 6H), 6.62 (d, J = 8.4 Hz, 2H), 7.07–7.42 (m,
10H), 7.66 (s, 2H), 7.99 (d, J = 8.4 Hz, 2H), 8.48 (s, 2H);
ms: (m/z, %): 476 (M+, 33), 185 (100), 109 (8), 108 (6), 77
(21). Anal. Calcd. for C28H24N6O2 (476.53): C 70.57, H
5.08%. Found: C 70.37, H 5.10%.
(4E)-4-[(4,5-Dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazolo-
4-yl)methylene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one
(6). (45%); mp 178–180ꢂC; pale yellow crystals; IR (KBr) ׳υ
(cmꢁ1), 3006, 2989, 2957, 1621, 1589, 1548, 1005, 754; ms:
(m/z, %): 358 (M+, 100), 315 (7), 266 (10), 225 (6), 197 (7), 128
(12), 91 (32), 77 (88). Anal. Calcd. for C21H18N4O2 (358.39):
C 70.38, H 5.06%. Found: C 70.46, H 5.13%.
EXPERIMENTAL
All melting points (uncorrected) were determined on a
Gallenkamp electric melting point apparatus. Elemental microa-
nalyses were carried out at Microanalytical Unit, Faculty of
Science (Cairo University) and the found values were within
0.4% of the theoretical values. The IR spectra were recorded
using KBr disc with a Mattson 5000 FTIR spectrometer (Faculty
of Science, Cairo University). The 1H NMR and 13C NMR
spectral data were measured in CDCl3 or DMSO-d6 on a Varian
XL 200, 300 MHz instruments using TMS as internal standard.
Chemical shifts were reported in ppm (d) downfield from internal
TMS and coupling constants are expressed in hertz. The Mass
spectra were recorded on GC-MS QP-1000 EX. Shimadzu Instru-
ment (Faculty of Science, Cairo University). The UV-vis spectral
absorptions were carried out with Unicam UV2-100 UV/Visible
1,4-Bis(3-methyl-1-phenyl-(4Z)-4-methylenylanilino-1H-
pyrazolo-5-(4H)-one)piperazine (9) and (Z)-ethyl 1-((3-methyl-
5-oxo-1-phenyl-1H-pyrazol-4(5H)-ylidene)(phenylamino)
methyl)piperidine-4-carboxylate (10).
A mixture of 8 [24]
(0.4 g, 1.23 mmol) and piperazine (0.06 g, 0.62 mmol) or ethyl
isonipicotate (0.72 g, 0.41 mmol) were fused in an oil bath at
120–140ꢂC for 3 h. The mixture was cooled and treated with
cold water (30 mL) or methanol (20 mL), the solid product that
formed was collected by filtration, dried and recrystallized from
DMF and methanol to afford 9 and 10, respectively.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

552
W. S. Hamama, H. G. El-Gohary, M. Soliman, and H. H. Zoorob
Vol 49
give 18 (45%); mp 208–210ꢂC; white crystals; IR (KBr) ׳υ
9; (62%); mp 250ꢂC; yellow crystals; IR (KBr) ׳υ (cmꢁ1),
1
(cmꢁ1), 3397, 3063, 2919, 2790, 1624, 1594, 1476, 1004, 757; H
3389, 3241, 3040, 2978, 2915, 1632, 1593, 1550, 1003, 758;
1H NMR (200 MHz, DMSO-d6): d, 2.18 (s, 6H), 2.24–2.87 (m,
8H), 6.88–8.1 (m, 20H), 9.67 (s, 2H); 13C NMR (200 MHz,
DMSO-d6): d, 170.2, 165.1, 147.8, 144.4, 137.9, 129.1, 124.4,
121.7, 118.6, 118.5, 116.9, 75.4, 48.3; ms: (m/z, %): 605 (M+,
4), 551 (22), 523 (17), 339 (24), 313 (61), 236 (56), 129 (68),
97 (100). Anal. Calcd. for C38H36N8O2 (636.74):C 71.68, H
5.70%. Found: C 71.52, H 5.64%.
10; (40%); mp 122–124ꢂC; pale yellow crystals; IR (KBr) ׳υ
(cmꢁ1), 3420, 3057, 2926, 1729, 1925, 1595, 1561, 1005, 757;
1H NMR (200 MHz, CDCl3): d, 1.26 (t, J = 4.8 Hz, 3H), 1.84
(q, J = 8.4 Hz, 4H), 2.09 (s, 3H), 2.48 (q, 1H), 3.18 (t, J = 8.4
Hz, 4H), 4.14 (q, J = 4.8 Hz, 2H), 4.74 (s, 1H), (NH, exchange-
able with D2O), 7.06–7.91 (m, 10H); ms: (m/z, %): 432 (M+,
6), 339 (5), 313 (7), 275 (34), 213 (10), 157 (10), 97 (23), 57
(100). Anal. Calcd. for C25H28N4O3 (432.51):C 69.42, H
6.53%. Found: C 69.40, H 6.60%.
NMR (200 MHz, DMSO-d6): d, 2.15 (s, 6H), 7.16–7.90 (m, 10H);
ms: (m/z, %): 346 (M++2, 10), 345 (M++1, 16), 344 (M+, 51), 315
(43), 239 (9), 211 (14), 174 (71), 132 (10), 91 (47), 77 (100).
Anal. Calcd. for C20H16N4O2 (344.37): C 69.76, H 4.68%. Found:
C 69.82, H 4.59%.
6-Amino-4-(4-methoxyphenyl)-2-oxo-1,2-dihydropyridine-
3,5-dicarbonitrile (23). A mixture of arylidine 19 (0.5 g, 1.7
mmol), cyanoacetamide (0.14 g, 1.7 mmol) and TEA (0.4 mL)
in ethanol (20 mL) were refluxed for 15 min then left to stand
at room temperature for two day, the solid precipitate was
filtered, dried and recrystallized from ethanol to give 23 (65%);
mp 205–207ꢂC, [Lit. [32], 205ꢂC (dec)]; white crystals; IR
(KBr) ׳υ (cmꢁ1), 3446, 3365, 3303, 3172, 2982, 2940, 2207,
1697, 1582, 1509, 1042, 727; 1H NMR (CDCl3): d, 3.89 (s,
3H), 6.96–7.26 (m, 4H), 7.8 (s, 2H), 8.26 (s, 1H); ms: (m/z, %):
266 (M+, 10), 203 (13), 202 (100), 158 (18), 89 (8), 77 (1).
Anal. Calcd. for C14H10N4O2 (266.25): C 63.15, H 3.79%.
Found: C 63.35, H 3.68%.
3-Methyl-4-(3-oxo-3-phenylpropyl)-1-phenyl-1H-pyrazol-5
(4H)-one (12). A mixture of 3-methyl-1-phenyl-1H-pyrazol-5
(4H)-one (1) (0.34 g, 1.95 mmol) and 11 (0.5 g, 1.95 mmol) in
methanol (20 mL) was refluxed over a steam bath for 3 h. The
reaction mixture was left to cool, filtered and the filtrate was
basified. The formed precipitate was filtered, dried and
recrystallized from ethanol to afford 12 (65%); mp 79ꢂC; white
crystals; IR (KBr) ׳υ (cmꢁ1), 3303, 3061, 2911, 1738, 1686,
1651, 1594, 1573, 1001, 751; 1H NMR (CDCl3): d, 2.04 (s,
3H), 2.25 (q, J = 4.0 Hz, 2H), 2.75 (t, J = 4.0 Hz, 2H), 3.34 (t,
J = 4.0 Hz, 1H), 7.2–8.0 (m, 10H); ms: (m/z, %): 306 (M+, 28),
187 (30), 186 (100), 105 (22), 149 (28), 125 (13), 83 (38), 57
(43). Anal. Calcd. for C19H18N2O2 (306.36): C 74.49, H 5.92%.
Found: C 74.52, H 6.02%.
(3-(4-Methoxyphenyl)-4-methyl-6-phenyl-2,3-dihydropyrazolo
[3,4-c]pyrazol-1(6H)-yl) (pyridin-4-yl)methanone (24).
A
mixture of the arylidine 19 (0.5 g, 1.7 mmol), nicotinic hydrazide
(0.24 g, 1.7 mmol) and triethylamine (0.4 mL) were heated for
15 min then left for two day at room temperature, the solid
precipitate was filtered, dried and recrystallized from ethanol to
furnish 24 (70%); mp 157–159ꢂC; pale yellow crystals; IR (KBr)
׳υ (cmꢁ1), 3445, 3043, 2993, 1658, 1602, 1551, 1025, 1548,
1408, 1328; 1H NMR (200 MHz, DMSO-d6): d, 2.48 (s, 3H),
3.82 (s, 3H), 7.02–7.83 (m, 13H), 8.41 (s, 1H), 8.79 (s, 1H); ms:
(m/z, %): 412 (M++1, 1), 411 (M+, 5), 276 (1), 275 (1), 185 (4),
135 (5), 133 (100), 106 (26), 78 (17). 106 (26), 78 (17). Anal.
Calcd. for C24H21N5O2 (411.46): C 70.06, H 5.14%. Found:
C 69.84, H 5.09%.
3-Methyl-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine (14).
A
mixture of 12 (0.5 g, 1.63 mmol) and ammonium carbonate (0.16
g, 1.63 mmol) in acetic acid (10 mL) was refluxed for 8 h, the
solvent was evaporated, the formed residue was neutralized with
diluted ammonium hydroxide, the solid precipitate was filtered
off and recrystallized from ethanol to give 14 (60%); mp 150ꢂC;
red crystals; IR (KBr) ׳υ (cmꢁ1), 3060, 2921, 1595, 1498, 1003,
755; ms: (m/z, %): 285 (M+, 4), 245 (21), 244 (100), 213 (13),
186 (37), 129 (25), 105 (62), 91 (20), 77 (72). Anal. Calcd. for
C19H15N3 (285.34): C 79.98, H 5.30%. Found: C 79.89, H 5.28%.
5,5a-Dihydro-5-(4-methoxyphenyl)-8-phenyl-1,3,6-trime-
thylpyrazolo[40,30:5,6]pyrido [2,3-d]thiopyrimidine-4(3H)
one (27). A mixture of arylidine 19 (0.5 g, 1.7 mmol), with
6-aminothiouracil (25) (0.22 g, 1.7 mmol) was refluxed in
ethanol (20 mL) in presence of catalytic amount of glacial
acetic acid for 8 h, left to stand at room temperature, water
basified by ammonium hydroxide was added. The solid
precipitate was collected by filtration and crystallized from
ethanol to give 27 (60%); mp 258–260ꢂC; white crystals; IR
(KBr) ׳υ (cmꢁ1), 3378, 2961, 2924, 1661, 1600, 1542, 1228,
1031, 771; 1H NMR (200 MHz, DMSO-d6): d, 2.50 (s, 3H),
2.69 (d, J = 12.8 Hz, 1H), 2.85 (d, J = 12.8 Hz, 1H), 3.69 (s,
3H), 5.28 (s, 1H), 6.76–7.00 (m, 9H), 7.93 (s, 1H), (NH,
exchangeable with D2O); ms: (m/z, %): 419 (M++2, 3), 385
(6), 278 (4), 263 (100), 262 (8), 233 (2), 232 (12), 108 (9),
107 (3), 77 (16). Anal. Calcd. for C22H19N5O2S (417.48):
C 63.29, H 4.59%. Found: C 63.12, H 4.70%.
5-(4-Methoxyphenyl)-8-phenyl-1,3,6-trimethylpyrazolo[40,30:
5,6]pyrido[2,3-d] pyrimidine-2,4(1H,3H)dione (29). A mixture
of arylidine 28 (0.5 g, 1.7 mmol) with 1,3-dimethyl-6-aminouracil
(26) (0.27 g, 1.7 mmol) was heated in glacial acetic acid (15 mL)
on steam bath for 18 h, the reaction mixture was left to cool, the
formed solid precipitate was collected by filtration, dried and
recrystallized from acetic acid to give 29 (65%); mp 240–242ꢂC;
white crystals; IR (KBr) ׳υ (cmꢁ1), 3058, 3002, 2918, 1698, 1599,
1503, 1030, 756; ms: (m/z, %): 428 (M++1, 27), 339 (3), 292 (6),
Ethyl 5-amino-3-methyl-1-phenyl-1H-thieno[3,2-c]pyrazole-6-
carboxylate (15).
A mixture of 1 (0.5 g, 2.87 mmol),
ethylcyanoacetate (0.31 g, 2.87 mmol), sulfur (0.09 g, 2.87 mmol)
and triethylamine (0.03 mL, 2.87 mmol) in ethanol (20 mL) was
stirred for 3 h at 40–50ꢂC, the formed precipitate was filtered, dried
and recrystallized from ethanol to afford 15 (45%); mp 120ꢂC; pale
yellow crystals; IR (KBr) ׳υ (cmꢁ1), 3153, 2919, 1608, 1535, 1000,
764; 1H NMR (200 MHz, DMSO-d6): d, 2.3 (s, 6H), 7.26–7.73 (m,
10H); ms: (m/z, %): 346 (M++2, 3), 345 (M++1, 4), 344 (M+, 11),
314 (8), 239 (2), 211 (4), 174 (34), 91 (43), 77 (12), 76 (100). Anal.
Calcd. for C20H16N4S (344.43):C 69.74, H 4.68%. Found: C 69.65,
H 4.66%.
4(Z)-3-Methyl-4-(3-methyl-5-oxo-1-phenyl-1H-pyrazolo-
4(5H)-ylidene)-1-phenyl-1H-pyrazol-5(4H)-one (18).
A mix-
ture of 1 (0.5 g, 2.87 mmol) and selenium oxide (0.33 g, 2.87
mmol) in ethanol (20 mL) was refluxed for 4 h, the formed black
powder was filtered off and the filtrate was left to cool. The solid
precipitate was filtered, dried and recrystallized from methanol to
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

May 2012
A Versatile Synthesis, PM3-Semiempirical, Antibacterial, and
Antitumor Evaluation of Some Bioactive Pyrazoles
553
272 (100), 215 (13), 155 (12), 136 (8), 57 (29). Anal. Calcd. for
C24H21N5O3 (427.46): C 67.44, H 4.95. Found: C 67.24, H 5.02%.
Further investigations UV stabilizer for polymers and thera-
peutic importance; as drugs, dyestuffs and light screening agents
of the compounds prepared in this work are still in progress and
will be published separately.
4-(4-Methoxyphenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-
b]quinolin-6-amine (32). A mixture of arylidine 19 (1.0 g, 1.7
mmol) and p-phenelendiamine (0.19 g, 1.71 mmol) were heated
for 4 h in ethylene glycol (20 mL) at 180ꢂC. After cooling the
solution was digested with methanol (20 mL) and refrigerated.
Insoluble dark red residue was filtered off and recrystallized
from toluene to give 32 (32%); mp 260ꢂC; colorless crystals; IR
(KBr) ׳υ (cmꢁ1), 3435, 3051, 2927, 2836, 1606, 1593, 1028,
752; ms: (m/z, %): 380 (M+, 60), 318 (9), 316 (41), 196 (3),
180 (5), 165 (7), 125 (16), 114 (16), 113 (100), 112 (14), 107
(16), 77 (44), 55 (56). Anal. Calcd. for C24H20N4O (380.44): C
75.77, H 5.30%. Found: C 75.43, H 5.51%.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet