Design and synthesis of novel methylene-bis-fused pyrazoles as biologically active molecules

Article abstract of DOI:10.1002/jhet.474

A series of novel methylene-bis-fused pyrazoles 12a-e and methylene-bis-2-(4-methylsulfonyl)-phenyl substituted fused pyrazoles 15a-d have been synthesized by the reaction of methylene-bis-aryl-6-hydroxymethylene-2- cyclohexenones 10 with hydrazine hydrat

Full text of DOI:10.1002/jhet.474

November 2010
Design and Synthesis of Novel Methylene-bis-fused Pyrazoles as
Biologically Active Molecules
1303
Ch. Sanjeeva Reddy,a* A. Srinivas,a M. Sunitha,a and A. Nagarajb
aDepartment of Chemistry, Kakatiya University, Warangal 506 009, India
bDepartment of Pharmaceutical Chemistry, Telangana University, Nizamabad 503 175, India
*E-mail: chsrkuc@yahoo.co.in
Received December 12, 2009
DOI 10.1002/jhet.474
Published online 20 August 2010 in Wiley Online Library (wileyonlinelibrary.com).
A series of novel methylene-bis-fused pyrazoles 12a–e and methylene-bis-2-(4-methylsulfonyl)-phe-
nyl substituted fused pyrazoles 15a–d have been synthesized by the reaction of methylene-bis-aryl-6-
hydroxymethylene-2-cyclohexenones 10 with hydrazine hydrate or (4-methylsulfonyl)-phenyl hydrazine
1
13. Chemical structures of all the newly synthesized compounds were elucidated by their IR, H NMR,
13C NMR, and MS spectral data. The compounds 15a–d were evaluated for their cyclooxygenase-2
(COX-2) inhibitory activity, and the compound 15b showed appreciable COX-2 inhibition and selectiv-
ity. Further, all the new compounds were screened for their antimicrobial activity against Gram-positive,
Gram-negative bacteria, and fungi. Amongst the screened compounds, 12c, 15a, and 15b were found to
be the most active against almost all the test bacteria. The compound 15b displayed notable antibacte-
rial activity against Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p), Micrococcus
luteus (IFC 12708), Proteus vulgaris (ATCC 3851), and Salmonella typhimurium (ATCC 14028), equal
to that of ampicillin. Similarly, these compounds also showed potent antifungal activity against Candida
albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185), and Tri-
chophyton mentagrophytes (IFO 40996).
J. Heterocyclic Chem., 47, 1303 (2010).
INTRODUCTION
lated by some promising pharmacological, agrochemical,
and analytical applications of its derivatives [11].
Pyrazole and its derivatives could be considered as
possible antimicrobial agents [1,2]. The other activities
include antidepressant [3], inhibitors of protein kinases
[4], antiagreegating [5], antiarthritic [6], and cerebro-
protectors [7]. Recently some aryl pyrazoles were
reported to have non-nucleoside HIV-1 reverse tran-
scriptase inhibitors [8], cyclooxygenase-2 (COX-2)
inhibitors [9], potent activator of the nitric oxide recep-
tor, and soluble guanylate cyclase [10] activity. Besides,
great interest in the pyrazole molecule has been stimu-
The role of COX-2 isoform in inflammation and the
attractiveness of COX-2 as a therapeutic target for the
development of anti-inflammatory drugs are very well
recognized [12]. The traditional nonsteroidal anti-inflam-
matory drugs (NSAIDs) are nonselectively inhibit both
COX-1 and COX-2, and hence, downregulate prosta-
glandin formation in almost all cells and tissues, which
may induce gastrointestinal side effect, adversely affect
the mucus-bicarbonate secretion, acid secretion, and mu-
cosal blood flow. COX-1 inhibition may also elicit an
C
V
2010 HeteroCorporation

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Ch. Sanjeeva Reddy, A. Srinivas, M. Sunitha, and A. Nagaraj
Vol 47
Scheme 1. COX-2 selective inhibitors.
tivity with reduced gastro intestinal side effects to tradi-
tional NSAIDs. However, the long term use of both tra-
ditional NSAIDs and coxibs has been reported to cause
significant cardiovascular side effects [14].
Following the successful introduction of antimicrobial
agents and COX-2 inhibitors, in continuation of our
research on biologically active heterocycles [15–18] it
was considered worthwhile to design and synthesize
more selective COX-2 analogs, incorporating two active
pharmacophores would enhance further the activity and
selectivity towards the COX-2 enzyme. In this article,
we explored fused pyrazoles 12a–e and 2-substituted
fused pyrazoles 15a–d in which central five-membered
scaffold is similar to that of celecosib 1, and 4-(methyl-
sulfonyl) benzene, used as a COX-2 pharmacophore,
and evaluated their in vitro antimicrobial and COX-2 in-
hibitory activity.
RESULTS AND DISCUSSION
Synthesis. The key intermediate, 10 required for the
synthesis of title compounds was prepared according to
the procedure outlined in the Scheme 2. Condensation
of commercially available salicylaldehyde 5 and triox-
ane in the presence of a mixture of conc. sulfuric acid
and acetic acid gave methylene-bis-salicylaldehyde 6 in
good yield [19]. Compound 6 was then reacted with the
corresponding acetophenone in presence of alc. KOH at
room temperature to give methylene-bis-chalcones 7a–e
(yield over 90%) [20]. Knoevenagel condensation of
compounds 7a–e with ethyl acetoacetate gave methyl-
ene-bis-aryl-6-carbethoxycyclohexenones 8a–e (yield
over 80%). Decarboxylation of 8a–e in the presence of
HCl/AcOH at reflux temperature resulted methylene-bis-
aryl-cyclohexenones 9a–e (yield over 80%), which on
Claisen-like condensation with ethylformate in the
increase in 5-lipoxygenase (5-LO) activity that would
potentiate production of leukotriene-B4 (LTB4) and va-
soconstrictor peptide-leukotrienes (p-LTs) by the lipoxy-
genase pathway, and this may also contribute to the vas-
cular and other mucosal damage by NSAIDs [13].
Hence, it was proposed that a selective inhibitor of
COX-2 would be an attractive approach to the treatment
of inflammatory conditions, without concomitant gastric
and renal side effects. There are four COX-2 selective
inhibitors, such as celecoxib (1), rofecoxib (2), valde-
coxib (3), and etoricoxib (4) (Scheme 1), which are cur-
rently prescribed for the treatment of arthritis and
inflammatory diseases. They show anti-inflammatory ac-
Scheme 2. Reagents and conditions: (i) trioxane, H2SO4/AcOH, reflux, 81%; (ii) RCOCH3, KOH/EtOH, rt, 82–95%; (iii) EAA, NaOEt/EtOH,
reflux, 78–86%; (iv) HCl/AcOH, reflux, 74–82%; (v) HCOOEt, NaOMe/C6H6, rt, 79–88%.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

November 2010
Design and Synthesis of Novel Methylene-bis-fused Pyrazoles as
Biologically Active Molecules
1305
Scheme 3. Reagents and conditions: (vi) hydrazinehydrate/AcOH, reflux, 80%; (vii) DDQ, N2-atm, reflux, 76–83%.
presence of sodium methoxide at room temperature
afforded methylene-bis-aryl-6-hydroxy-methylene-2-cyclo-
hexenones 10a–e in good yields.
observed nearly at 137.2, 137.4, 155.6, 145.3 ppm,
respectively.
Further, the intermediate 10 when treated with the
commercially available 4-(methylsulfonyl)-phenylhydra-
zine 13 in refluxing ethanol gave methylsulfonyl deriva-
tive of pyrazole 14a–d in good yield. This reaction is a
regioselective transformation and the 2-substituted pyr-
azole could be generated almost exclusively by carrying
out the condensation in the presence of hydrochloric
acid and one equivalent of 4-(methyl- sulfonyl)phenyl
hydrazine 13. The compounds 14a–d when aromatized
with DDQ under N2-atmosphere at reflux temperature
gave 4-(methylsulfonyl)-phenyl substituted fused pyra-
zoles 15a–d in good yields (Scheme 4). The chemical
structures of all the synthesized compounds were con-
The compounds 10a–e on cyclocondensation with the
hydrazine hydrate in refluxing acetic acid resulted dihy-
dropyrazole derivatives 11a–e in good to excellent
yields (yield over 80%). Subsequent aromatization of
11a–e, with dichlorodicyanoparabenzoquinone (DDQ)
under N2-atmosphere at reflux temperature gave fused
pyrazoles 12a–e in good yields (Scheme 3). The chemi-
cal structure of the compounds was elucidated by their
1
IR, H NMR, 13C NMR, and MS spectral data. In the
IR spectra of compounds 12a–e, C¼¼N and NAH bands
were observed in the regions 1560–1585, 3390–3410
cmꢀ1 respectively. According to the IR spectral data,
1
1
the compounds 12a–e have pyrazole structure. In the H
firmed by their IR, H NMR, 13C NMR, and MS spec-
NMR spectra of 12a–e, the absence of signals corre-
sponding to methine and methylene protons of cyclohex-
adiene ring indicates that aromatization has indeed taken
place. The ANH proton of the pyrazole ring was
observed as a broad singlet at about 8.87–8.80 ppm. The
signal because of the methylene bridge proton, present
in all compounds, appeared at 4.06–4.00 ppm as singlet.
The N¼¼CH proton of compounds 12a–e appeared at
7.95–7.90 ppm as singlet. All the other aromatic and ali-
phatic protons of compounds 12a–e were observed at
the expected regions. In the 13C NMR spectra of com-
pounds 12a–e, the prominent signals corresponding to
C-3, C-3a, C-4, and C-7a, for all the compounds,
tral data. In the IR spectra of compounds 15a–d, C¼¼N
band was observed in the region 1560–1585 cmꢀ1 and
SO2 group symmetric, asymmetric stretching bands at
about 1300–1328, 1155–1165 cmꢀ1. In the 1H NMR
spectrum of compounds 15a–d, absence of the signal
corresponding to NH group proved that these com-
pounds have pyrazole nucleus with (4-methyl- sulfonyl)-
phenyl group at nitrogen. Further, the ACH3 proton sig-
nal was seen as singlet at about 2.96–2.90 ppm, and the
signal of N¼¼CH proton of compounds 15a–d appeared
at 6.68–6.65 ppm proved that these compounds have
pyrazole nucleus with (4-methylsulfonyl)phenyl group at
nitrogen. All the other aromatic and aliphatic protons of
Scheme 4. Reagents and conditions: (viii) HCl/EtOH, reflux, 78–86%; (ix) DDQ/dry C6H6, N2-atm, reflux, 79–86%.
Journal of Heterocyclic Chemistry
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Ch. Sanjeeva Reddy, A. Srinivas, M. Sunitha, and A. Nagaraj
Vol 47
Table 1
Antibacterial activity of compounds 12a–e and 15a–d.
Minimum inhibitory concentration (MIC, lg/mL)
Compound
B. subtilis
S. aureus
M. luteus
P. vulgaris
S. typhimurium
E. coli
12a
12b
12c
12d
12e
15a
15b
15c
—
3.12
3.12
25.0
12.5
3.12
1.56
12.5
12.5
1.56
—
6.25
3.12
—
—
3.12
1.56
25.0
12.5
3.12
1.56
12.5
6.25
1.56
—
6.25
1.56
—
—
3.12
3.12
—
—
—
25.0
—
12.5
3.12
1.56
12.5
6.25
1.56
12.5
3.12
1.56
12.5
6.25
3.12
12.5
6.25
1.56
12.5
6.25
3.12
—
—
25.0
—
—
12.5
15d
Ampicillin
—, Indicates bacteria are resistant to the compound >50 lg/mL concentration.
compounds 15a–d were observed at the expected
regions. In the 13C NMR spectra of compounds 15a–d,
the prominent signals corresponding to C-3, C-3a, C-4,
and C-7a, for all the compounds, observed nearly at
125.4, 124.0, 136.0, 153.1 ppm, respectively, provide
further evidence for their structures. Mass spectra of all
the synthesized compounds showed Mþ/Mþ þ 1 peaks,
in agreement with their molecular formulae.
towards E. coli bacteria. The remaining compounds
showed moderate to good activity.
Antifungal activity. The newly prepared compounds
were screened for their antifungal activity against Can-
dida albicans (ATCC 10231), Aspergillus fumigatus
(HIC 6094), Trichophyton rubrum (IFO 9185), and Tri-
chophyton mentagrophytes (IFO 40996). The antifungal
activity of each compound was compared with standard
drug Amphotericin B. MIC (lg/mL) was determined
and compared with controls; the MIC values of the com-
pounds screened are given in Table 2. The antifungal
screening data showed only moderate activity of the test
compounds. Among the screened compounds, only 15b
showed the highest activity against all the microorgan-
isms used. Similarly compound 12c is also highly active
but only against T. rubrum and T. mentagrophytes. The
activities of these two compounds are almost equal to
Antibacterial activity. The in vitro antibacterial ac-
tivity of the newly prepared compounds, 12a–e and
15a–d, was assayed against gram-positive bacteria viz.
Bacillus subtilis (ATCC 6633), Staphylococcus aureus
(ATCC 6538p), and Micrococcus luteus (IFC 12708),
Gram-negative bacteria viz. Proteus vulgaris (ATCC
3851), Salmonella typhimurium (ATCC 14028), and
Escherichia coli (ATCC 25922) by the broth dilution
method, recommended by National Committee for Clini-
cal Laboratory standards (NCCLS) [21]. Amphicillin
was used as a standard drug, the lowest concentration
(highest dilution) required to arrest the growth of bacte-
ria was regarded as minimum inhibitory concentration
(MIC, lg/mL), was determined and compared with the
controls, the MIC values of the compounds assayed are
presented in Table 1.
Table 2
Antifungal activity of compounds 12a–e and 15a–d.
Minimum inhibitory concentration
(MIC, lg/mL)
C.
A.
T.
T.
Investigation of the antibacterial screening data
revealed that all the tested compounds exhibit interest-
ing biological activity, however, with a degree of varia-
tion. Compound 15b is highly active against all the
microorganisms used (accept E. coli) at 1.56 lg/mL
concentration, and is almost equal to the standard. Com-
pound 12c is also highly active against M. luteus and P.
vulgaris only at the same concentration as 15b. The
compound 15a also showed good antibacterial activity
against B. subtilis, S. aureus, M. luteus, and P. vulgaris.
Compound 12a is almost inactive towards all the micro-
Compound
albicans fumigatus rubrum mentagrophytes
12a
12b
12c
12d
12e
15a
15b
15c
—
12.5
12.5
—
50.0
12.5
—
25.0
12.5
—
25.0
12.5
—
12.5
25.0
25.0
6.25
6.25
50.0
50.0
12.5
25.0
25.0
12.5
6.25
6.25
6.25
6.25
50.0
25.0
50.0
25.0
25.0
12.5
25.0
25.0
15d
Amphotericin B
6.25
3.12
3.12
3.12
—, Indicates fungi are resistant to the compound >50 lg/mL
concentration.
organisms used. Other compounds were also inactive
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

November 2010
Design and Synthesis of Novel Methylene-bis-fused Pyrazoles as
Biologically Active Molecules
1307
Ethyl-6-(5-{3-[6-(ethoxycarbonyl)-5-oxo-3-phenyl-3-cyclo-
hexenyl]-4-hydroxybenzyl}-2-hydroxyphenyl)-2-oxo-4-phe-
nyl- 3-cyclohexene-1-carboxylate (8a). In a solution sodium
metal (2 g) in ethanol (30 mL), a mixture of freshly distilled
ethylacetoacetate (3.9 mL, 0.03 mol) and compound 7a (4.6 g,
0.01 mol) dissolved in ethanol (20 mL) was added. The result-
ing solution was refluxed on a water bath for 4 h. Allowing
the reaction mixture to cool and crystallization of the ppt.
from ethanol to give 8a as brown solid; Yield 82%; m.p. 150–
the standard, the remaining compounds showed moder-
ate to good activity.
COX-2 inhibitory activity. The compounds synthe-
sized 15a–d was evaluated as COX inhibitors in human
whole blood (HWB). Among the four compounds, 15b
showed good inhibition and selectivity. Some interesting
features can be deduced from the comparison of the
structure of compound 15b with that of celecoxib 1. (i)
The sulfonamide group present in celecoxib is replaced
by methyl sulfonyl group, believed to be crucial for
increasing the COX-2 selectivity. (ii) The 4-methyl-
phenyl and the trifluoromethyl groups on pyrazole ring
are replaced and is fused with 1,3-diarylbenzene. (iii)
Two similar pharmacophores were introduced in a single
molecular frame work, linked by a methylene bridge.
We evaluated the compound 15b for COX inhibition in
the HWB assay, performed essentially as described [22].
The 2-(4-methylsulfonyl)phenyl-substituted compound
15b showed 69.51% of COX-2 inhibition at 3 lM in
HWB assay, compared with 90.90% inhibition observed
for celecoxib 1 at the same concentration. The com-
pound 15b showed only moderate COX-1 inhibition at a
very high concentration (50 lM) for about 21.02%.
In conclusion, a series of novel methylene-bis-fused
pyrazoles 12a–e and methylene-bis-2(4-methylsulfonyl)-
phenyl substituted fused pyrazoles 15a–d have been
designed and synthesized. The antimicrobial activity of
these compounds was evaluated against various Gram-
positive, Gram-negative bacteria, and fungi. Among the
synthesized compounds, 12c, 15a, and 15b showed good
activity against bacteria and fungi and emerged as
potential molecules for further development. The com-
pounds were also evaluated for their COX-2 selective
inhibition, 15b showed an appreciable COX-2 inhibition
and selectivity. With this set of analogs, we are now in
a position to investigate the multiple biological activities
for these compounds.
52ꢁC; IR (KBr): m 3452, 3065, 1702, 1695, 1597, 1245 cmꢀ1
;
1H NMR (DMSO-d6): d 7.10–7.14 (m, 10 H, ArH), 6.80 (s,
2H, ArH), 6.79 (d, J ¼ 9.2 Hz, 2H, ArH), 6.62 (d, J ¼ 9.2
Hz, 2H, ArH), 6.10 (s, 2H, CH), 5.20 (s, 2H, OH), 4.06 (q,
4H, CH2), 3.87 (q, 2H, CH), 3.81 (d, 2H, CH), 3.72 (s, 2H,
CH2), 2.87 (d, 4H, CH2), 1.10 (t, 6H, CH3); 13C NMR
(DMSO-d6): d 190.1, 176.7, 154.6, 149.5, 142.3, 133.4, 130.0,
128.7, 128.2, 127.9, 125.5, 123.8, 121.9, 117.4, 61.2, 60.6,
42.1, 37.0, 30.7, 17.0. MS: m/z 685 (Mþ þ 1). The other com-
pounds 8b–e were prepared by the similar procedure.
5-{2-Hydroxy-5-[4-hydroxy-3-(5-oxo-3-phenyl-3-cyclohex-
enyl)benzyl]phenyl-3-phenyl}-2-cyclohexen-1-one (9a). To a
mixture of glacial acetic acid (100 mL) and conc. HCl (50
mL) was added compound 8a (6.5 g, 0.01 mol) in portions.
The mixture was heated to reflux for 10 h. After cooling to
room temperature, the reaction mixture was concentrated in
vacuo. The residue was taken up with ethyl acetate and
washed with water and brine, dried over MgSO4, filtered, and
evaporated in vacuo to give oil, which soon solidified; it was
purified by recrystallization from ethanol to give the com-
pound 9a as brown solid; Yield 79%; m.p. 132–34ꢁC; IR
(KBr): m 3357, 3025, 2932, 1687, 1596 cmꢀ1 1H NMR
;
(DMSO-d6): d 7.10–7.14 (m, 10H, ArH), 7.00 (d, J ¼ 9.2 Hz,
2H, ArH), 6.82 (s, 2H, ArH), 6.62 (d, J ¼ 9.2 Hz, 2H, ArH),
6.10 (s, 2H, CH), 5.20 (s, 2H, OH), 3.83–3.87 (m, 2H, CH),
3.72 (s, 2H, CH2), 2.70 (d, 4H, CH2), 2.67 (d, 4H, CH2); 13C
NMR (DMSO-d6): d 190.0, 155.2, 150.1, 140.5, 132.3, 131.2,
128.5, 127.8, 127.4, 126.2, 124.5, 122.6, 116.1, 47.5, 42.0,
38.9, 31.0; MS: m/z 541 (Mþ þ 1). The other compounds 9b–
e were prepared by the similar procedure.
5-[2-Hydroxy-5-(4-hydroxy-3-{6-[(Z)-1-hydroxymethyli-
dene]-5-oxo-3-phenyl-3-cyclohexenyl}benzyl)phenyl]-6-[(Z)-1-
hydroxymethylidene]-3-phenyl-2-cyclohexen-1-one (10a). In
a solution of 10% sodium methoxide (10 mL) in benzene (25
mL), ethylformate (2.24 mL, 0.03 mol) was added and after-
ward over 30 min, compound 9a (5.4 g, 0.01 mol) dissolved in
benzene (10 mL) was added. The resulting solution was stirred
for 10 h at room temperature and allowed to stand over night,
then evaporated to dryness. The suspension obtained was
mixed with cold water and acidified with dil HCl (20 mL) and
extracted three times with ether (40 mL). The organic layer
was dried over MgSO4 and evaporated in vacuo to give solid,
was purified by crystallization in ethanol to afford pure 10a as
yellow solid; Yield 81%; m.p. 143–45ꢁC; IR (KBr): m 3320,
EXPERIMENTAL
Research chemicals were either purchased from Aldrich
Company or Fluka or used without further purification in the
reactions, or were prepared according to procedures described
in the literature. Reactions were monitored by thin layer chro-
matography on silica gel plated (60 F254; Merck) visualizing
with ultraviolet light or iodine. Column chromatography was
performed on silica gel 60 (0.043–0.060 mm), Merck. The
reported yields of the products are unoptimized. Melting points
were determined with a Fisher-Johns apparatus and are uncor-
rected. IR spectra were recorded on a Perkin-Elmer FTIR 5000
spectrometer, using KBr pellet. 1H NMR, 13C NMR spectra
were recorded on a Varian Gemini spectrometer, operating at
300, 75 MHz, respectively. Chemical shifts (d) are reported as
parts per million downfield from tetramethyl silane. Mass spec-
tra were obtained on a VG micromass 7070H spectrometer.
1
3028, 2952, 1662, 1620, 1597 cmꢀ1; H NMR (DMSO-d6): d
8.97 (s, 2H, OH), 7.92 (s, 2H, CH), 7.14–7.10 (m, 10H, ArH),
6.80 (s, 2H, ArH), 6.49–6.40 (m, 4H, ArH), 5.67 (s, 2H, CH),
4.12 (t, 2H, CH), 3.72 (s, 2H, CH2), 3.22 (d, 4H, CH2); 13C
NMR (DMSO-d6): d 191.3, 167.6, 156.1, 149.7, 142.0, 131.1,
130.6, 130.2, 128.9, 128.0, 127.9, 127.6, 126.2, 116.7, 115.5,
44.1, 42.0, 37.8; MS: m/z 596 (Mþ). The other compounds
10b–e were prepared by the similar procedure.
Journal of Heterocyclic Chemistry
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Ch. Sanjeeva Reddy, A. Srinivas, M. Sunitha, and A. Nagaraj
Vol 47
(KBr): m 3387, 3042, 2932, 1585, 686 cmꢀ1
;
1H NMR
4-[4-Hydroxy-3-(6-phenyl-4,5-dihydro-1H-4-indazolyl)ben-
(DMSO-d6): d 8.86 (bs, 2H, NH), 8.15 (s, 2H, ArH), 8.10 (s,
2H, ArH), 7.94 (s, 2H, ArH), 7.82 (d, J ¼ 8.2 Hz, 4H, ArH),
7.41 (s, 2H, ArH), 7.32–7.26 (m, 6H, ArH), 7.00 (s, 2H, ArH)
6.94 (d, J ¼ 9.0 Hz, 2H, ArH) 4.02 (s, 2H, CH2); 13C NMR
(DMSO-d6): d 158.7, 155.6, 147.4, 146.1, 141.7, 139.0, 137.2,
136.5, 134.9, 134.2, 134.0, 128.7, 126.4, 125.4, 123.8, 118.3,
112.7, 42.2; MS: m/z 654 (Mþ).
4-{4-Hydroxy-3-[6-(4-methoxyphenyl)-1H-4-indazolyl]ben-
zyl}-2-[6-(4-methoxyphenyl)-1H-4-indazolyl]phenol (12e). This
was obtained as brown solid; Yield 80%; m.p. 122–24ꢁC; IR
(KBr): m 3400, 3042, 2962, 1584, 1030 cmꢀ1 1H NMR
;
zyl]-2-(6-phenyl-4,5-dihydro-1H-4-indazolyl)phenol (11a). To
a solution of 10a (5.9 g, 0.01 mol) in glacial acetic acid (50
mL), hydrazine hydrate (1.5 g, 0.03 mol) was added. After
stirring at 80ꢁC for 10 h, the mixture was concentrated
in vacuo. To the residue was added water and twice extracted
with ether, washed the organic layer with saturated NaHCO3
solution, subsequently with water and brine, dried over
MgSO4, and evaporated to dryness. The residue could be
recrystallized from ethanol to afford 11a as brown solid; Yield
79%; m.p. 123–25ꢁC; IR (KBr): m 3390, 3037, 2972, 1595,
1585 cmꢀ1 1H NMR (DMSO-d6): d 8.12 (bs, 2H, NH), 7.65
;
(DMSO-d6): d 8.87 (bs, 2H, NH), 8.14 (s, 2H, ArH), 8.10 (s,
2H, ArH), 7.94 (s, 2H, ArH), 7.47 (s, 2H, ArH), 7.39 (d, J ¼
8.4 Hz, 4H, ArH), 7.32 (d, J ¼ 9.0 Hz, 2H, ArH), 6.94 (d,
J ¼ 9.0 Hz, 2H, ArH), 6.84 (d, J ¼ 8.4 Hz, 4H, ArH), 4.02 (s,
2H, CH2), 3.84 (s, 6H, OCH3); 13C NMR (DMSO-d6): d
161.2, 159.0, 155.6, 149.5, 146.1, 141.7, 139.2, 137.4, 136.5,
134.2, 133.2, 129.4, 129.0, 125.7, 124.3, 123.8, 118.2, 112.7,
112.0, 54.7, 42.2; MS: m/z 645 (Mþ þ 1).
(s, 2H, ArH), 7.63 (s, 2H, ArH), 7.32 (d, J ¼ 9.2 Hz, 4H,
ArH), 7.21 (s, 2H, ArH), 6.99–7.05 (m, 6H, ArH), 6.84 (d,
J ¼ 9.1 Hz, 2H, ArH), 6.73 (d, J ¼ 9.0 Hz, ArH), 6.62 (s, 2H,
OH), 4.92 (t, 2H, CH), 3.72 (s, 2H, CH2), 2.92 (d, 4H, CH2);
13C NMR (DMSO-d6): d 156.2, 148.7, 143.4, 140.3, 132.8,
132.0, 130.9, 130.0, 128.9, 127.8, 126.9, 126.5, 125.4, 118.7,
117.2, 42.1, 39.3, 38.1; MS: m/z 589 (Mþ þ 1). The other
compounds 11b–e were prepared by the similar procedure.
4-[4-Hydroxy-3-(6-aryl-1H-4-indazolyl)benzyl]-2(6-aryl-
1H-4-indazolyl)phenol (12a–e). To a solution of correspond-
ing compound 11 (0.01 mol) in dry benzene (20 mL), DDQ
(0.03 mol) dissolved in dry benzene (20 mL) was added in
portions. The mixture was heated to reflux and stirred for 5 h
under a nitrogen atmosphere. The precipitated DDQ-H2 was
filtered off and the filtrate was subjected to column chromatog-
raphy on silica gel (60–120 mesh) to afford pure compounds.
4-[4-Hydroxy-3-(6-phenyl-1H-4-indazolyl)benzyl]-2(6-phe-
nyl-1H-4-indazolyl)phenol (12a). This was obtained as yellow
solid; Yield 83%; m.p. 137–39ꢁC; IR (KBr): m 3392, 3062,
4-{6-(4-Bromophenyl)-4-[5-(3-{6-(4-bromophenyl)-2-[4-(meth-
ylsulfonyl)phenyl]-4,5-dihydro-2H-4-indazolyl}-4-hydroxy ben-
zyl)-2-hydroxyphenyl]-4,5-dihydro-2H-2-indazolyl}-1-benzene
sulfonic acid (14a). To a stirred solution of 10b (7.5 g, 0.01
mol) in ethanol (100 mL) and 6 N HCl (14.8 mL, 0.892 mol)
was added 4-(methylsulfonyl)phenyl hydrazine 13 (4.1 g,
0.022 mol). The mixture was heated to reflux and stirred for
10 h. After cooling to room temperature, the reaction mixture
was concentrated in vacuo. The residue was taken up with
ethyl acetate and washed with water and brine, dried over
MgSO4, filtered, and evaporated in vacuo to give a solid that
was crystallized from diisopropyl ether (100 mL) to give pyr-
azole 14a as brown solid; Yield 82%; m.p. 222–24ꢁC; IR
1
2985, 1584 cmꢀ1. H NMR (DMSO-d6): d 8.87 (bs, 2H, NH),
7.47 (s, 2H, ArH), 7.32–7.26 (m, 8H, ArH) 6.94 (d, J ¼ 9.0
Hz, 2H, ArH) 4.05 (s, 2H, CH2); 13C NMR (DMSO-d6): d
159.0, 155.6, 147.9, 146.1, 145.3, 141.7, 139.0, 137.2, 136.5,
134.2, 128.8, 126.9, 126.5, 125.4, 123.8, 118.2, 112.7, 42.1;
MS: m/z 585 (Mþ þ 1).
(KBr): m 3400, 3062, 2937, 1585, 1328, 1165, 732 cmꢀ1 1H
;
NMR (DMSO-d6): d 7.91 (s, 2H, ArH), 7.67–7.62 (m, 6H,
ArH), 7.50–7.42 (m, 12H, ArH), 7.23 (s, 2H, ArH), 6.94 (s,
2H, OH), 6.84 (d, J ¼ 8.9 Hz, 2H, ArH), 6.77 (d, J ¼ 8.9 Hz,
2H, ArH), 4.87 (t, 2H, CH), 3.72 (s, 2H, CH2), 3.12 (d, 4H,
CH2), 2.94 (s, 6H, CH3); 13C NMR (DMSO-d6): d 156.1,
154.2, 153.5, 142.7, 138.8, 133.5, 132.3, 130.4, 129.9, 129.1,
128.0, 126.8, 126.4, 124.6, 124.2, 122.4, 120.7, 119.4, 118.2,
43.5, 42.3, 41.6, 38.7; MS: m/z 1056 (Mþ). The other com-
pounds 14c–d were also prepared by the similar procedure.
4-{6-(aryl)-4-[5-(3-{6-(aryl)-2-[4-(methylsulfonyl)phenyl]-2
H-4-indazolyl}-4-hydroxybenzyl)-2-hydroxyphenyl]-2H-2-in-
dazolyl}-1-benzenesulfonic acid (15a–d). To a solution of 14
(0.005 mol) in dry benzene (20 mL), DDQ (0.015 mol) in dry
benzene (20 mL) was added in portions. The mixture was
heated to reflux and stirred for 5 h under a nitrogen atmos-
phere. The precipitated DDQ-H2 was filtered off and the fil-
trate was subjected to column chromatography on silica gel
(60–120 mesh), to afford pure compounds.
2-[6-(4-Bromophenyl)-1H-4-indazolyl]-4-3-[6-(4-bromo-
phenyl)-1H-4-indazolyl]-4-hydroxybenzylphenol
(12b). This
was obtained as brown solid; Yield 82%; m.p. 142–44ꢁC; IR
1
(KBr): m 3400, 3037, 2962, 1585, 712 cmꢀ1; H NMR (DMSO-
d6): d 8.86 (bs, 2H, NH), 8.15 (s, 2H, ArH), 8.10 (s, 2H, ArH),
7.94 (s, 2H, ArH), 7.47 (s, 2H, ArH), 7.41 (d, J ¼ 8.3 Hz, 4H,
ArH), 7.32–7.26 (m, 6H, ArH), 6.94 (d, J ¼ 9.0 Hz, 2H, ArH),
4.02 (s, 2H, CH2); 13C NMR (DMSO-d6): d 159.0, 155.6,
149.3, 146.1, 141.7, 139.1, 137.4, 137.1, 136.5, 134.3, 131.2,
129.4, 125.4, 123.9, 118.3, 112.7, 42.1; MS: m/z 743 (Mþ þ 1).
2-[6-(4-Aminophenyl)-1H-4-indazolyl]-4-3-[6-(4-aminophenyl)-
1H-4-indazolyl]-4-hydroxybenylphenol (12c). This was obtained
as orange solid; Yield 76%; m.p. 151–53ꢁC; IR (KBr): m 3395,
1
3061, 2937, 1585 cmꢀ1; H NMR (DMSO-d6): d 8.84 (bs, 2H,
NH), 8.15 (s, 2H, ArH), 8.10 (s, 2H, ArH), 7.94 (s, 2H, ArH),
7.62 (d, J ¼ 8.4 Hz, 4H, ArH), 7.47 (s, 2H, ArH), 7.28 (d,
J ¼ 9.0 Hz, 2H, ArH), 6.94 (d, J ¼ 9.0 Hz, 2H, ArH), 6.62
(d, J ¼ 8.4 Hz, 4H, ArH), 6.32 (bs, 4H, NH2), 4.02 (s, 2H,
CH2); 13C NMR (DMSO-d6): d 159.1, 155.6, 149.7, 146.1,
142.4, 141.6, 139.0, 137.2, 136.5, 134.9, 134.2, 130.2, 124.2,
123.8, 118.2, 113.1, 112.7, 42.2; MS: m/z 615 (Mþ þ 1).
2-[6-(4-Clorophenyl)-1H-4-indazolyl]-4-{3-[6-(4-chlorophenyl)-
1H-4-indazolyl]-4-hydroxy}benzylphenol (12d). This was
obtained as yellow solid; Yield 81%; m.p. 115–17ꢁC; IR
4-{6-(4-Bromophenyl)-4-[5-(3-{6-(4-bromophenyl)-2-[4-(meth-
ylsulfonyl)phenyl]-2H-4-indazolyl}-4-hydroxybenzyl)-2-hydro
xyphenyl]-2H-2-indazolyl}-1-benzenesulfonic acid (15a). This
was obtained as brown solid; Yield 80%; m.p. 210–12ꢁC; IR
(KBr): m 3400, 3062, 2937, 1585, 1328, 1165, 736 cmꢀ1 1H
.
NMR (DMSO-d6): d 8.14 (s, 2H, ArH), 7.80 (s, 2H, ArH),
7.72 (d, J ¼ 8.3 Hz, 4H, ArH), 7.53–7.48 (m, 8H, ArH), 7.32–
7.28 (m, 6H, ArH), 6.84–6.78 (m, 4H, ArH, OH), 6.72 (s, 2H,
ArH), 4.02 (s, 2H, CH2), 2.94 (s, 6H, CH3); 13C NMR
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

November 2010
Design and Synthesis of Novel Methylene-bis-fused Pyrazoles as
Biologically Active Molecules
1309
(DMSO-d6): d 153.1, 152.0, 143.3, 142.9, 136.7, 136.2, 133.3,
130.7, 129.8, 129.0, 128.7, 127.9, 125.4, 124.0, 123.9, 122.3,
119.7, 117.6, 111.3, 110.4, 44.3, 42.4; MS: m/z 1050 (Mþ).
4-{6-(4-aminophenyl)-4-[5-(3-{6-(4-aminophenyl)-2-[4-(meth-
ylsulfonyl)phenyl]-2H-4-indazolyl}-4-hydroxybenzyl)-2-hydro
xyphenyl]-2H-2-indazolyl}-1-benzenesulfonic acid (15b). This
was obtained as orange solid; Yield 84%; m.p. 240–42ꢁC; IR
providing NMR and mass spectral data. Financial assistance from
the UGC SAP (Phase-I)-DRS Programme, New Delhi, India, is
greatly acknowledged.
REFERENCES AND NOTES
[1] Baraldi, P. G.; Pavani, M. G.; Nunez, M.; Brigidi, P.; Vitali,
B.; Gambari, R.; Romagnoli, R. Bioorg Med Chem 2002, 10, 449.
[2] Lee, K. Y.; Kim, J. M.; Kim, J. N. Tetrahedron Lett 2003,
44, 6737.
1
(KBr): m 3400, 3065, 2932, 1589, 1328, 1162 cmꢀ1; H NMR
(DMSO-d6): d 8.14 (s, 2H, ArH), 7.80 (s, 2H, ArH), 7.72 (d,
J ¼ 8.2 Hz, 4H, ArH), 7.67 (d, J ¼ 8.6 Hz, 4H, ArH), 7.53
(d, J ¼ 8.2 Hz, 4H, ArH), 7.32 (d, J ¼ 8.6 Hz, 2H, ArH),
6.94 (d, J ¼ 9.1 Hz, 2H, ArH), 6.72 (d, J ¼ 8.6 Hz, 4H,
ArH), 5.96 (s, 2H, OH), 4.96 (bs, 4H, NH2), 4.02 (s, 2H,
CH2), 2.94 (s, 6H, CH3); 13C NMR (DMSO-d6): d 153.1,
152.0, 147.3, 145.2, 143.3, 138.2, 136.7, 130.7, 129.7, 129.0,
126.2, 125.6, 124.0, 123.9, 122.3, 121.0, 119.7, 117.6, 111.9,
110.4, 44.3, 42.4; MS: m/z 924 (Mþ þ 1).
[3] Erhan, P.; Mutlu, A.; Tayfun, U.; Dilek, E. Eur J Med
Chem 2001, 36, 539.
[4] Giesc, N. A.; Lokker, N.; Laibelman, A. M.; Searbrough,
R. M. Chem Absrt 1996, 135, 105089.
[5] Bruno, O.; Ranise, A.; Bonduvalli, F.; Schenone, S.; Amico,
M.; Falciani, M.; Vacca, C.; Filippli, A. Il Farmaco 1994, 49, 533.
[6] Richard, A. N.; Megan, M.; Stephen, T. S.; Colin, J. D.;
Robert, J. S.; Nigel, D. S.; Louise, A. G.; Sharon, K. S.; Danielle, G.
A.; Karen, A. R.; Norman, A. R. J Med Chem 1993, 36, 134.
[7] Hiroshi, K.; Yasuhiro, T.; Yoshio, S.; Fumiki, S.; Norio, O.;
Akira, T. Jpn J Pharmacol 1997, 73, 317.
4-{6-(4-Chlorophenyl)-4-[5-(3-{6-(4-chlorophenyl)-2-[4-(meth-
ylsulfonyl)phenyl]-2H-4-indazolyl}-4-hydroxybenzyl)-2-hydro
xyphenyl]-2H-2-indazolyl}-1-benzenesulfonic acid (15cꢁ). This
was obtained as yellow solid; Yield 79%; m.p. 196–98 C; IR
[8] Genin, M. J.; Bilers, C.; Keiser, B. J.; Poppe, S. M.; Swa-
ney, S. M.; Tarpley, W. G.; Yagi, Y.; Romero, D. L. J Med Chem
2000, 43, 1034.
[9] Habeb, A. G.; Rao, P. N. P.; Knaus, E. E. J Med Chem
2001, 44, 3039.
(KBr): m 3410, 3065, 2932, 1586, 1328, 1162, 686 cmꢀ1 1H
;
NMR (DMSO-d6): d 8.14 (s, 2H, ArH), 7.95 (d, J ¼ 8.6 Hz,
4H, ArH), 7.80 (s, 2H, ArH), 7.68 (d, J ¼ 8.9 Hz, 4H, ArH),
7.59 (d, J ¼ 8.9 Hz, 4H, ArH), 7.47 (d, J ¼ 8.6 Hz, 4H,
ArH), 7.32 (d, J ¼ 9.0 Hz, 2H, ArH), 6.90 (d, J ¼ 9.0 Hz,
2H, ArH), 6.68 (s, 2H, ArH), 5.92 (s, 2H, OH), 4.02 (s, 2H,
CH2), 2.96 (s, 6H, CH3); 13C NMR (DMSO-d6): d 153.1,
152.0, 146.6, 143.3, 136.9, 136.0, 134.9, 133.3, 131.2, 130.0,
129.8, 129.0, 128.6, 125.6, 124.0, 123.9, 122.7, 122.0, 119.7,
117.6, 110.4, 109.7, 44.3, 42.2; MS: m/z 963 (Mþ þ 1).
[10] David, L. S.; David, G. B.; Joanna, B.; Guillaume, E. B.; Rich-
ard, O. C.; Surinder, S. C.; Ian, G. C.; Patricia, A. F.; Robert, C. G.;
Maria, C. G.; Adrian, J. H.; Marcel, R. K.; Qian, L.; David, J. M.; Sylvie,
M.; Kenneth, L. P.; Karen, R.; Graham, D. S.; Jeremy, N. S.; Mark, A. T.;
Kerry, A. W.; Grant, W.; Chi-kit, W. J Med Chem 2001, 44, 78.
[11] Al-Allaf, T. A. K.; Rashan, L. J Boll Chim Farm 2001,
140, 205.
[12] Turini, M. E.; DuBois, R. N. Annu Rev Med 2002, 53, 35.
[13] Dubois, A. Prostag Other Lipid Mediat 1999, 56, 341.
[14] Garcia, R. L. A.; Hernandez, D. S. Epidemiology 2003, 14, 240.
[15] Sanjeeva Reddy, Ch.; Nagaraj, A. Heterocycl Commun
2007, 13, 67.
4-[4-[2-Hydroxy-5-(4-hydroxy-3-{6-(4-methoxyphenyl)-2-
[4-(methylsulfonyl)phenyl]-2H-4-indazolyl}benzyl)phenyl]-6-
(4-methoxyphenyl)-2H-2-indazolyl]-1-benzene sulfonic acid
(15d). This was obtained as brown solid; Yield 86%; m.p.
209–11ꢁC; IR (KBr): m 3400, 3065, 2937, 1589, 1328, 1162
1
cmꢀ1; H NMR (DMSO-d6): d 8.14 (s, 2H, ArH), 7.68 (d, J ¼
[16] Sanjeeva Reddy, Ch.; Nagaraj, A. Chin Chem Lett 2007,
18, 1213.
8.1 Hz, 4H, ArH), 7.68 (d, J ¼ 8.9 Hz, 4H, ArH), 7.59 (d,
J ¼ 8.9 Hz, 4H, ArH), 7.47 (d, J ¼ 8.1 Hz, 4H, ArH), 7.32
(d, J ¼ 9.0 Hz, 2H, ArH), 6.90 (d, J ¼ 9.0 Hz, 2H, ArH),
6.89 (d, J ¼ 8.1 Hz, 4H, ArH), 6.68 (s, 2H, ArH), 5.96 (s, 2H,
OH), 4.02 (s, 2H, CH2), 3.89 (s, 6H, OCH3), 2.96 (s, 6H,
CH3); 13C NMR (DMSO-d6): d 159.6, 153.9, 153.4, 152.0,
143.3, 136.7, 133.8, 133.1, 130.7, 129.8, 129.0, 125.6, 124.7,
124.0, 123.8, 122.3, 119.7, 117.6, 113.0, 110.9, 110.4, 55.6,
44.3, 42.4; MS: m/z 955 (Mþ þ 1).
[17] Sanjeeva Reddy, Ch.; Nagaraj, A. J Heterocyclic Chem
2007, 44, 1357.
[18] Sanjeeva Reddy, Ch.; Nagaraj, A. J Iran Chem Soc 2008, 5, 262.
[19] Marvel, C. S.; Tarkoy, N. J Am Chem Soc 1957, 79, 6000.
[20] Sanjeeva Reddy, Ch.; Nagaraj, A. J Heterocycl Chem 2007,
44, 1181.
[21] National Committee for Clinical Laboratory Standards
(NCCLS). Standard methods for dilution antimicrobial susceptibility
tests for bacteria, which grows aerobically; Nat Comm Lab Stands:
Villanova, 1982; p 242.
Acknowledgments. The authors are grateful to the Director, In-
dian Institute of Chemical Technology, Hyderabad, India, for
[22] Young, J. M.; Panah, S.; Satchawat, C, C.; Cheung, P. S.
Inflammation Res 1996, 45, 246.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet