Synthesis, characterization and pharmacological screening of some novel 5-imidazopyrazole incorporated polyhydroquinoline derivatives

Article abstract of DOI:10.1016/j.ejmech.2014.02.015

A new category of polyhydroquinoline derivatives 8a-t were synthesized in moderate to good yield (64-85%) by one-pot three-component cyclocondensation reaction of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 3 with various enaminones

Full text of DOI:10.1016/j.ejmech.2014.02.015

European Journal of Medicinal Chemistry 78 (2014) 207e216
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis, characterization and pharmacological screening of some
novel 5-imidazopyrazole incorporated polyhydroquinoline derivatives
*
Piyush N. Kalaria, Shailesh P. Satasia, Dipak K. Raval
Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar 388 120, Gujarat, India
a r t i c l e i n f o
a b s t r a c t
Article history:
A newcategoryof polyhydroquinoline derivatives8aet weresynthesizedinmoderate togoodyield (64e85%)
by one-pot three-component cyclocondensation reaction of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-
pyrazole-4-carbaldehyde 3 with various enaminones 6aeh and different active methylene compounds
(malononitrile 7a, ethylcaynoacetate 7b and caynoacetamide 7c) in absolute ethanol. The newly synthesized
compounds were evaluated for their in vitro antimalarial activity against Plasmodium falciparum, in vitro
antibacterial activity against a panel of pathogenic strains of bacteria and fungi and also for their antituber-
cular activity against Mycobacterium tuberculosis H37Rv strain. Two of them (8n, 8t) exhibited excellent
antimalarial activity. Some of them exhibited excellent antibacterial activity and moderate antituberculosis
activity compared with the first line drugs.
Received 8 July 2013
Received in revised form
6 September 2013
Accepted 8 February 2014
Available online 19 March 2014
Keywords:
Multicomponent reaction
5-Imidazopyrazole incorporated
polyhydroquinolines
Antimicrobial activity
Antituberculosis activity
Antimalarial activity
Ó 2014 Elsevier Masson SAS. All rights reserved.
1. Introduction
have combined applications as antimalarial, antituberculosis and
antimicrobial agents.
Malaria is presently prevalent in a broad band around the
equator, in areas of the Americas, many parts of Asia, and much of
the Africa; however, it is in sub-Saharan Africa where 85e90% of
malaria fatalities occur [1]. The World Health Organization has
estimated that in 2010, 216 million documented cases of malaria
were reported. Around 655,000 people died from the disease, most
of them were children in Africa http://en.wikipedia.org/wiki/
Malaria [2]. The emergence and spread of drug-resistant malarial
parasites further intensify this serious situation and has com-
pounded the need for the development of new, cost effective
antimalarial. Similarly tuberculosis is the second most common
reason of death from infectious disease after those due to HIV/AIDS
http://en.wikipedia.org/wiki/Tuberculosis [3]. One third of the
world’s population is suspected to have been infected with Myco-
bacterium tuberculosis, with new infections occurring at a rate of
about one per second http://en.wikipedia.org/wiki/Tuberculosis
[4]. In 2010, there were an estimated 8.8 million new cases and
1.5 million associated deaths mostly found in developing countries
http://en.wikipedia.org/wiki/Tuberculosis [5]. In this context, it was
thought worth to synthesize various novel compounds which may
Among the heterocyclic motifs, azoles constitute enormously
important members due to their presence in a multitude of
bioactive natural products as privileged pharmacophores. Imid-
azole and its derivatives are of great significance due to their
important roles in biological systems such as antimicrobial [6],
anti-inflammatory [7], antitubercular [8], analgesic, anti-
convulsant [9], anticancer and anti-parkinson [10] activities. Pyr-
azole containing compounds have received significant interest
owing to their various chemotherapeutic potentials including ver-
satile antineoplastic activities. Many pyrazole derivatives are re-
ported to have the broad spectrum of biological activities, such as
antimicrobial [11], anti-inflammatory [12e14], antifungal [15],
antitumour, cytotoxic, molecular modelling [16e18] and antiviral
[19,20] activities.
Much interest has been dedicated to the synthesis of poly-
hydroquinoline compounds due to their diverse therapeutic and
pharmacological properties, such as antitumour, antiathero-
sclerotic, vasodilator, geroprotective, bronchodilator and hep-
atoprotective activity [21]. The polyhydroquinoline ring is one of
the important heterocyclic core constitutes and prominent struc-
tural motif found in numerous pharmaceutically active compounds.
Specifically 4-substituteted 1, 4-dihydropyridines (1, 4-DHPs) are
well known as Ca2þ channel blockers and have emerged as one
of the most important class of drugs for the treatment of
* Corresponding author.
E-mail addresses: dipanalka@yahoo.com, dk_raval@spuvvn.edu (D.K. Raval).
http://dx.doi.org/10.1016/j.ejmech.2014.02.015
0223-5234/Ó 2014 Elsevier Masson SAS. All rights reserved.

208
P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
cardiovascular diseases [22]. In addition to the diverse biological
activities of polyhydroquinoline, other heterocycles in association
with polyhydroquinoline play an essential role in numerous bio-
logical processes and possess significant chemical and pharmaco-
logical importance. In view of the above biological importance, our
aim was to develop new approaches for a variety of heterocycles
incorporating polyhydroquinoline scaffold. We attempted to
involve pyrazole and imidazole in one molecule which may play a
vital role as an important creation part in title compounds.
In continuation to our research work [23], we report herein on
the utility of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azole-4-carbaldehyde as the building block for the synthesis of
functionalized polyhydroquinoline scaffold. Study on their phar-
macological broadcast in order to get some innovative compounds
that could be optimized for potent antimicrobial, antimalarial and
antituberculosis agents is also included.
The starting material 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-
carbaldehyde 1 was prepared according to VilsmeiereHaack reac-
tion of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one [24]. The final
aldehyde 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-
carbaldehyde 3 was prepared by refluxing compound 1 and imid-
azole in presence of anhydrous K2CO3 as basic catalyst in DMF as
solvent. The required enaminones 6aeh were prepared by the re-
action of
b-diketones 4aeb with various amines under aqueous
condition. The final molecules substituted 4-(5-(1H-imidazol-1-yl)-
3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-amino-1-phenyl-4,6,7,8-
tetrahydroquinolin-5(1H)-one were synthesized by refluxing the
mixture of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazole-
4-carbaldehyde 3, various enaminones 6aeh and different active
methylenecompounds (malononitrile 7a, ethylcayno acetate 7b and
caynoacetamide 7c) in absolute ethanol using piperidine as the
basic catalyst (Scheme 1). The formation of quinoline derivatives
8aet was attempted through an in situ initial formation of heter-
ylidenenitrile, containing the electron-poor C]C double bond, from
the Knoevenagel condensation between aldehyde 3 and various
active methylene compounds 7aec by loss of water molecules.
Finally, Michael addition of enaminones 6aeh to the heterylidene
2. Chemistry
The synthesis of targeted 5-imidazopyrazole incorporated
polyhydroquinoline derivatives are summarized in Scheme 1.
Scheme 1. Synthesis of the substituted 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-amino-1-phenyl-4,6,7,8-tetrahydroquinolin-5(1H)-one 8aet. (i) DMF,
K2CO3, Reflux 2 h (ii) PEG 600: deionized water (1:1), Reflux 0.5e1 h (iii) Ethanol, Piperidine, Reflux 1e3 h.

P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
209
olefins gave acyclic intermediate which underwent cyclization by
3.2. In vitro antituberculosis activity
nucleophilic attack of the NH group on the cyano carbon, followed
by tautomerization to afford cyclized polyhydroquinoline de-
rivatives 8aet.
The cheering results from the antibacterial activity impelled us
to opt for preliminary screening of the title compounds for their
in vitro antituberculosis activity. Primary screening of all the newly
synthesized compounds 8aet was conducted at 250
mg/mL and
3. Pharmacology
100 g/mL against M. tuberculosis H37Rv strain by using Low-
m
ensteineeJensen medium (conventional method) as described by
Rattan [26]. The obtained results are presented in Table 2 in the
form of % inhibition. Rifampicin and Isoniazid were used as the
standard drugs.
3.1. In vitro antimicrobial activity
The minimal inhibitory concentration (MIC) of all synthesized
compounds 8aet was determined by broth microdilution method
according to National Committee for Clinical Laboratory Standards
(NCCLS) [25]. Antibacterial activity was screened against three
Gram positive (Streptococcus pneumoniae MTCC 1936, Bacillus
subtilis MTCC 441 and Clostridium tetani MTCC 449) and three Gram
negative (Escherichia coli MTCC 443, Salmonella typhi MTCC 98,
Vibrio cholerae MTCC 3906) bacteria by using ampicillin, cipro-
floxacin, norfloxacin and chloramphenicol as the standard anti-
bacterial drugs. Antifungal activity was screened against two fungal
species (Candida albicans MTCC 227 and Aspergillus fumigats MTCC
3008) where nystatin and griseofulvin were used as the standard
antifungal agents. The strains employed for the activity were pro-
cured from the Institute of Microbial Technology, Chandigarh
(MTCC-Micro Type Culture Collection). Mueller Hinton broth was
used as nutrient medium to grow and dilute the drug suspension
for the test. 2% aqueous DMSO was used as the diluent to get the
desired concentration of compound to test upon the standard
bacterial strains. The results of antimicrobial screening data are
shown in Table 1.
3.3. In vitro antimalarial activity
All the synthesized title compounds 8aet were evaluated for
their in vitro antimalarial activity against Plasmodium falciparum
strain using chloroquine and quinine as the reference compounds.
The consequences of the antimalarial screening are expressed as
the drug concentration resulting in 50% inhibition (IC50) of parasite
growth and are listed in Table 3.
4. Results and discussion
4.1. Analytical results
The structures of all the synthesized compounds were
confirmed by 1H NMR, FT-IR, 13C NMR, mass and elemental
analysis. The 1H NMR spectra of compound 8aet exhibited the
presence of the eCH (C4 of polyhydroquinoline ring) proton as a
sharp singlet around
arising at 7.77e7.95 ppm due to imidazole proton (NeCHeN).
The aromatic protons resonate as multiplets at around 6.93e
d 4.32e4.88 ppm and one more singlet
Table 1
In vitro antimicrobial activity (MIC,
m
g/mL) of compounds 8aet.
d
d
Entry Gram positive bacteria
Gram negative bacteria
Fungi
C.A.
7.70 ppm. The IR spectrum of compounds 8aet exhibited char-
acteristic absorption band around 1663e1646 cmꢀ1 which was
attributed to the presence carbonyl group (C5 of poly-
hydroquinoline ring). The strong absorption band was observed
in the range of 1369e1376 cmꢀ1 due to eCH3 stretching. The
characteristic absorption band in the range 3459e3333 cmꢀ1
may be attributed to asymmetric and symmetric stretching of e
NH2. In 13C NMR spectra, the carbonyl carbon (C5 of poly-
S.P.
B.S.
C.T.
E.C.
S.T.
V.C.
A.F.
MTCC
1936
MTCC
441
MTCC
449
MTCC
443
MTCC
98
MTCC
3906
MTCC MTCC
227
3008
8a
8b
8c
8d
8e
8f
8g
8h
8i
125
100
250
125
125
200
200
250
250
500
500
200
125
200
200
125
100
100
250
250
100
25
100
250
250
200
100
200
250
62.5
200
250
250
125
100
500
500
200
125
125
200
200
250
50
100
250
200
125
125
200
500
200
250
500
200
125
200
200
250
200
100
250
200
200
250
100
50
200
125
200
500
100
250
200
200
250
100
250
200
250
200
200
125
200
100
62.5
200
100
25
62.5
100
200
500
100
250
250
200
125
125
200
250
250
250
200
200
100
200
200
100
100
25
250
100
250
250
200
500
250
200
250
100
125
250
125
62.5
125
200
250
250
200
500
100
25
1000
1000
>1000 250
>1000 500
>1000 500
1000
>1000
hydroquinoline ring) was displayed at
d 195.4e196.9 ppm. The
250
500
500
500
1000
250
250
1000
1000
250
500
1000
1000
500
1000
n.t.a
n.t.
1000
signals at around 57.9e78.5 ppm, 78.3e78.6 ppm and 76.3e
d
1000
>1000
1000
500
500
1000
500
500
1000
500
500
1000
500
76.8 ppm were assigned to carbon attached to carbonitrile, ester
and amide group respectively. The mass spectrum of all the
compounds showed molecular ion peak at Mþ corresponding to
8j
8k
8l
8m
8n
8o
8p
8q
8r
8s
8t
A
B
C
D
E
Table 2
In vitro antituberculosis activity (% inhibition) of compounds 8aet against
M. tuberculosis H37Rv (at concentration 250
mg/mL and 100
m
g/mL).
Entry
% Inhibition
Entry
% Inhibition
250
m
g/mL
100
m
g/mL
250
m
g/mL
100 mg/mL
1000
n.t.
n.t.
n.t.
n.t.
8a
8b
8c
8d
8e
8f
8g
8h
8i
90
12
35
84
63
75
94
20
70
33
45
80
6
8l
8m
8n
8o
8p
8q
8r
8s
7
45
38
12
84
91
25
41
67
98
99
4
38
34
9
75
88
20
37
60
98
99
10
50
n.t.
n.t.
100
50
n.t.
10
10
10
n.t.
n.t.
100
500
30
76
58
66
94
12
61
28
37
50
n.t.
n.t.
50
50
50
n.t.
n.t.
n.t.
100
100
F
n.t.
n.t.
n.t.
n.t.
S.P.: Streptococcus pneumoniae, B.S.: Bacillus subtilis, C.T.: Clostridium tetani, E.C.:
Escherichia coli, S.T.: Salmonella typhi, V.C.: Vibrio cholerae, C.A.: Candida albicans,
A.F.: Aspergillus fumigatus, MTCC: Microbial Type Culture Collection. A: Ampicillin, B:
Ciprofloxacin, C: Norfloxacin, D: Chloramphenicol, E: Nystatin, F: Griseofulvin.
The bold characters indicate the higher or equal activity compared to standard
drugs.
8t
8j
8k
Rifampicin
Isoniazid
The bold characters indicate the higher or equal activity compared to standard
drugs.
a
n.t.: not tested.

210
P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
Table 3
and 100
mg/mL against tuberculosis H37Rv strain. The bioassay
In vitro antimalarial activity of compounds 8aet.
results obtained for the efficacy of all the synthesized analogues
against Mycobacterium tuberculosis H37Rv is summarized in
Table 2. The outcome of the result revealed that, compounds 8a
(R2 ¼ CH3, X ¼ CN), 8g (R2 ¼ OH, X ¼ CN) and 8q (R2 ¼ OCH3, X ¼ CN)
were found to possess excellent activity (i.e. 90%, 94% and 91% at
Entry
IC50
(
m
g/mL)
Entry
IC50 (mg/mL)
8a
8b
8c
8d
8e
8f
8g
8h
8i
1.073
1.79
8l
8m
8n
8o
8p
8q
8r
8s
0.62
0.71
0.034
0.072
0.57
0.086
1.49
0.067
0.033
0.020
0.268
1.025
0.073
0.057
0.059
1.23
0.096
0.057
1.082
1.47
250
compounds, the compound 8g (R2 ¼ OH, X ¼ CN) showed brilliant
activity at both the concentration i.e. 94% at 250 g/mL and 100 g/
mg/mL) against M. tuberculosis H37Rv. Among the above three
m
m
mL. While compounds 8d (R2 ¼ Cl, X ¼ CN) and 8p (R3 ¼ OH,
X ¼ CONH2) are moderately active against M. tuberculosis H37Rv. All
other compounds showed poor inhibition of M. tuberculosis growth.
From the above results, it can be concluded that, compound 8q
(R2 ¼ OCH3, X ¼ CN) 8g (R2 ¼ OH, X ¼ CN) may become new class of
antitubercular agents in future.
8t
8j
8k
Chloroquine
Quinine
The bold characters indicate the higher or equal activity compared to standard
drugs.
4.2.4. Antimalarial activity
their molecular weights, which confirmed the respective chem-
All the synthesized compounds 8aet were evaluated for their
antimalarial activity against chloroquine and quinine sensitive
strain of Plasmodium falciparum. All experiments were performed
in duplicate and a mean value of IC50 is mentioned in Table 3. As
shown in Table 3, the compounds 8d (R2 ¼ Cl, X ¼ CN), 8e (R2 ¼ Cl,
X ¼ COOEt), 8f (R2 ¼ Cl, X ¼ CONH2), 8h (R2 ¼ OH, X ¼ COOEt), 8i
(R2 ¼ OH, X ¼ CONH2), 8n (R3 ¼ OH, X ¼ CN), 8o (R3 ¼ OH,
X ¼ COOEt), 8q (R2 ¼ OCH3, X ¼ CN), 8s (R2 ¼ OH, X ¼ COOEt) and 8t
(R1 ¼ H, R2 ¼ OH, X ¼ CONH2) were found to have IC50 in the range
of 0.033e0.096 against P. falciparum strain. These compounds dis-
played marvellous activity against P. falciparum strain as compared
to quinine IC50 0.268. Moreover compounds 8n (R3 ¼ OH, X ¼ CN)
and 8t (R1 ¼ H, R2 ¼ OH, X ¼ CONH2) were found to possess
moderate activity i.e. IC50 0.033 and 0.034 aligned with chloro-
quine. Remaining all other compounds were found to be less active
against P. falciparum strain against chloroquine and quinine as the
standard drugs.
ical structures.
4.2. Biological section
4.2.1. Antibacterial activity
The analysis of antibacterial screening data (Table 1) revealed
that all the compounds 8aet showed moderate to very good
inhibitory activity. The compound 8h (R2 ¼ OH, X ¼ COOEt) showed
maximum activity i.e. 62.5 mg/mL against B. subtilis. Majority of the
compounds showed excellent activity against gram positive bac-
teria B. subtilis and C. tetani as compared to ampicillin
(MIC ¼ 250 g/mL), while compounds 8b (R2 ¼ CH3, X ¼ COOEt), 8c
m
(R2 ¼ CH3, X ¼ CONH2), 8g (R2 ¼ OH, X ¼ CN), 8j (R2 ¼ H, X ¼ CN), 8k
(R2 ¼ H, X ¼ COOEt) and 8b (R2 ¼ CH3, X ¼ COOEt), 8i (R2 ¼ OH,
X ¼ CONH2), 8q (R2 ¼ OCH3, X ¼ CN), 8r (R2 ¼ OCH3, X ¼ COOEt)
showed similar activity as that of the standard drugs against
B. subtilis and C. tetani, at 250 mg/mL concentration. The compounds
8b (R2 ¼ CH3, X ¼ COOEt), 8q (R2 ¼ OCH3, X ¼ CN), and 8r
4.2.5. Structureeactivity relationship (SAR)
(R2 ¼ OCH3, X ¼ COOEt) displayed comparatively good activities i.e.
The results of the biological evaluation revealed that the activity
was considerably affected by various substituents on the aromatic
ring present at first position in polyhydroquinoline derivatives. The
hydroxyl group present at various positions in phenyl ring played
an important role for the divergence in activity [27]. We observed
that the presence of hydroxyl group at ortho position showed sig-
nificant potency against Bacillus subtilis and Clostridium tetani;
while at meta position, it showed maximum activity against
V. cholerae and C. tetani as well as increased activity against Plas-
modium falciparum. The hydroxyl group present at para position
offered higher antifungal activity against C. albicans. Chloro sub-
stitution at para position on phenyl ring showed excellent anti-
malarial activity against P. falciparum. Whereas methoxy group
present at para position on phenyl ring showed very good antitu-
berculosis activity against Mycobacterium tuberculosis H37Rv as
well as showed best antibacterial activity against all 3 g positive
bacteria. Carbonitrile, ester and amide groups present at third po-
sition in polyhydroquinoline ring were also found responsible for
variation in activity. Particularly the carbonitrile group was found
accountable for increasing antituberculosis activity against
M. tuberculosis H37Rv whereas ester and amide groups were
responsible for increased antifungal activity against C. albicans. The
strongly active compounds of the series with reference to the
standard drugs are shown in Scheme 2.
100
m
g/mL against S. pneumonia. The compounds 8a (R2 ¼ CH3,
X ¼ CN), 8n (R3 ¼ OH, X ¼ CN) and 8s (R1 ¼ H, R2 ¼ OH, X ¼ COOEt)
illustrated highest activity in inhibiting gram negative bacteria i.e.
62.5 mg/mL against S. typhi, V. cholera and E. coli. Compounds 8b
(R2 ¼ CH3, X ¼ COOEt), 8e (R2 ¼ Cl, X ¼ COOEt) and 8j (R2 ¼ H,
X ¼ CN) also showed same potency against all gram negative bac-
teria. While compounds 8q (R2 ¼ OCH3, X ¼ CN), 8t (R1 ¼ H,
R2 ¼ OH, X ¼ CONH2) and 8r (R2 ¼ OCH3, X ¼ COOEt) showed same
potency as that of standard drugs against S. typhi and E. coli.
Remaining other compounds are moderate or less active against all
gram positive and gram negative bacteria.
4.2.2. Antifungal activity
The result of antifungal study (Table 1) of the synthesized pol-
yhydroquinoline derivatives revealed that all the compounds have
poor activity against A. fumigates. Where as in comparison with
standard fungicidal griseofulvin (MIC ¼ 500
mg/mL), compounds 8f
(R2 ¼ Cl, X ¼ CONH2), 8k (R2 ¼ H, X ¼ COOEt), 8l (R2 ¼ Cl,
X ¼ CONH2) and 8o (R3 ¼ OH, X ¼ COOEt) contributed excellent
antifungal activity i.e. 250 mg/mL against C. albicans. While com-
pounds 8g (R2 ¼ OH, X ¼ CN), 8h (R2 ¼ OH, X ¼ COOEt), 8i (R2 ¼ OH,
X ¼ CONH2) and 8s (R1 ¼ H, R2 ¼ OH, X ¼ COOEt) showed same
potency i.e. 500
mg/mL against C. albicans. All other compounds
showed weak antifungal potency than nystatin and griseofulvin.
5. Conclusion
4.2.3. Antituberculosis activity
Antituberculosis screening of all the newly synthesized com-
pounds 8aet was conducted at two concentrations i.e. 250 mg/mL
The objective of the present study was to synthesize and
examine the antimicrobial, antimalarial and antituberculosis

P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
211
Scheme 2. Strong antibacterial, antifungal, antitubercular and antimalarial compounds from the series.
activities of some newly functionalized pyrazole incorporated
6.1.1. General procedure for the synthesis of 5-(1H-imidazol-1-yl)-
3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (3)
polyhydroquinoline compounds in search of new structural leads
looking promising as potent antimicrobial, antimalarial and anti-
tuberculosis agents. This synthetic approach allows the incorpo-
ration of three potent bioactive nuclei in a single scaffold through
an easy way. Except only two compounds, all the compounds
were found to be active against B. subtilis and C. tetani and nearly
about half of the compounds showed excellent antifungal activity
against Candida albicans. The compounds 8a, 8d, 8g, 8p and 8q
exhibited good antituberculosis activities. Majority of the com-
pounds showed excellent activity against strains of P. falciparum as
compared to quinine.
5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 1(1.1 g,
5 mmol), appropriate imidazole 2 (0.51 g, 7.5 mmol) and anhydrous
potassium carbonate (0.6 g, 10 mmol) in dimethylformamide (5 mL)
were charged in a 50 mL round bottom flask with mechanical stirrer
and condenser. The reaction mixture was refluxed for 2 h and the
progress of the reactionwas monitored by TLC. After the completion of
reaction (as evidenced by TLC), the reaction mixture was cooled to
room temperature and then poured into ice cold water (50 mL) with
continuous stirring followed by neutralization with 1 N HCl until pH 7.
The separated precipitates of 5-(1H-imidazol-1-yl)-3-methyl-1-
phenyl-1H-pyrazole-4 carbaldehyde 3 were filtered, thoroughly
washed with water, dried, and recrystallized from ethanol.
6. Experimental section
Yield 79%; m.p. 204 ꢂC; 1H NMR (400 MHz, DMSO-d6):
d 2.59 (s,
3H, CH3), 7.07e7.46 (m, 7H, AreH), 7.94 (s, 1H, imidazole), 9.74 (s,
6.1. Chemistry
1H, CHO); ESI-MS (m/z): Calcd. 252.2, found 253.0 (Mþ)
All reactions were performed with commercially available re-
agents. They were used without further purification. The solvents
used were of analytical grade. All reactions were monitored by
thin-layer chromatography (TLC) on aluminum plates coated with
silica gel 60 F254, 0.25 mm thickness (Merck). Detection of the
components was made by exposure to iodine vapours or UV light.
6.1.2. Synthesis of the substituted 3-(phenylamino)cyclohex-2-
enone (substituted enaminones) (6aeh)
Cyclohexane e 1,3 e dione or dimedone (10 mmol), substituted
amines (10 mmol) and PEG (polyethylene glycol):deionised water
(5 mL:5 mL) were charged in a 50 mL round bottom flask with
mechanical stirrer and condenser. The reaction mixture was
refluxed for 0.5e1 h. After the completion of reaction (checked by
TLC), the substituted enaminones (6 a-h) were filtered and washed
with deionised water. The further purification was carried out by
leaching in equal volume ratio of water and methanol (10:10 mL) to
obtain the pure solid sample.
Melting points were taken in melting point apparatus mThermo-
Cal10 (Analab Scientific Pvt. Ltd, India) and are uncorrected. The IR
spectra were recorded in KBr on a PerkineElmer Spectrum GX FT-IR
Spectrophotometer (PerkineElmer, USA) and only the character-
istic peaks are reported in cmꢀ1. Mass spectra were recorded on
Shimadzu LCMS 2010 spectrometer (Shimadzu, Tokyo, Japan) pur-
chased under PURSE program of DST at Sardar Patel University,
Vallabh Vidyanagar. 1H and 13C Nuclear Magnetic Resonance
spectra were recorded in DMSO-d6 on a Bruker Avance 400F (MHz)
spectrometer (Bruker Scientific Corporation Ltd., Switzerland) us-
ing residual solvent signal as an internal standard at 400 MHz and
100 MHz respectively. Chemical shifts are reported in parts per
million (ppm). Splitting patterns were designated as follows: s,
singlet; d, doublet; dd, doublet of doublet and m, multiplet. The
elemental analysis was carried out by using PerkineElmer 2400
series-II elemental analyzer (PerkineElmer, USA) and all com-
pounds are within ꢁ0.4% of the theoretical compositions. Yields are
not optimized. Ampicillin, griseofulvin, isoniazid and nystatin were
purchased from local market.
6.1.3. Synthesis of the substituted 4-(5-(1H-imidazol-1-yl)-3-
methyl-1-phenyl-1H-pyrazol-4-yl)-2-amino-1-phenyl-4,6,7,8-
tetrahydroquinolin-5(1H)-one (8aet)
A 50 mL round bottom flask, fitted with a reflux condenser, was
charged with
a mixture of 5-(1H-imidazol-1-yl)-3-methyl-1-
phenyl-1H-pyrazole-4-carbaldehyde 3 (1 mmol), malononitrile or
caynoacetamide or ethylcayno acetate (1 mmol) 7aec, substituted
enaminones 6aeh (1 mmol), and catalytic amount of piperidine (2e
3 drops) in ethanol (10 mL). The mixture was heated under reflux for
1e3 h and the progress of the reaction was monitored by TLC. After
the completion of reaction, the reaction mixture was cooled to room
temperature and stirred magnetically for further 10 min. The solid

212
P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
mass separated was collected by filtration, washed well withethanol
(10 mL) and crystallized from hot chloroform (10 mL). The physi-
cochemical and spectroscopic characterization data of the synthe-
sized compounds 8aet are given below.
(C^N stretching), 1644(C]O stretching), 1376 (eCH3 stretching);
13C NMR (100 MHz, DMSO-d6)
: 13.1 (CH3), 27.3, 27.9 (2C, CH3),
28.5 (C4), 32.3 (C(CH3)2), 41.5, 49.8 (2(CH2)2), 58.1 (CeCN), 108.5,
121.0, 121.9, 122.5,122.7, 127.8, 129.7, 129.8,130.7,132.4,134.9,135.1,
138.1, 147.5, 150.8, 151.2 (16C, AreC), 195.7 (C]O); 1H NMR
d
6.1.3.1. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-7,7-dimethyl-5-oxo-1-p-tolyl-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8a). Yield 80%; m.p. 278 ꢂC; IR
(KBr, nmax, cmꢀ1): 3459 & 3333 (asym. & sym. stretching of e NH2),
2950 (Ar CeH), 2921 (CeH asym. stretching of CH2 group), 2177
(C^N stretching), 1641(C]O stretching), 1371 (eCH3 stretching);
(400 MHz, DMSO-d6): d 0.83 (s, 3H, CH3), 0.87 (s, 3H, CH3), 1.74 (d,
J ¼ 17.2 Hz, 1H, CH2), 1.93 (d, J ¼ 17.2 Hz, 1H, CH2), 2.11 (s, 2H, CH2),
2.38 (s, 3H, CH3), 4.33 (s, 1H, CH), 5.48 (s, 2H, NH2), 7.08e7.65 (m,
11H, AreH), 7.82 (s, 1H, imidazole); ESI-MS (m/z): Cacld. 549.2,
found 550.1 (Mþ), 551.2 (Mþ2); Anal. Calcd. (%) for C34H36N6O3:C,
67.69; H, 5.13; N, 17.82. Found: C, 67.72; H, 5.01; N, 17.67.
13C NMR (100 MHz, DMSO-d6)
d: 13.2 (CH3), 22.2 (CH3), 27.3, 28.0
(2C, CH3), 28.5 (C4), 32.4 (C(CH3)2), 41.5, 49.9 (2(CH2)2), 58.3 (Ce
CN), 108.1, 121.0, 121.9, 122.5, 122.7, 127.8, 129.67, 129.8, 130.7, 132.4,
134.9, 134.9, 138.1, 147.5, 150.8, 151.3 (16C, AreC), 195.7 (C]O); 1H
6.1.3.5. Ethyl 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-1-(4-chlorophenyl)-7,7-dimethyl-5-oxo-
1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (8e). Yield 78%; m.p.
234 ꢂC; IR (KBr, nmax, cmꢀ1): 3412 & 3369 (asym. & sym. stretching
of eNH2), 2955 (Ar CeH), 2925 (CeH asym. stretching of CH2
group), 1639 (C]O stretching), 1371 (eCH3 stretching); 13C NMR
NMR (400 MHz, DMSO-d6):
d 0.93 (s, 3H, CH3), 0.95 (s, 3H, CH3),
1.84 (dd, J ¼ 26.8, 17.2 Hz, 2H, CH2), 2.15 (dd, J ¼ 20.4, 16.4 Hz, 2H,
CH2), 2.48 (s, 3H, CH3), 2.50 (s, 3H, CH3), 4.03 (s, 2H, NH2), 4.62 (s,
1H, CH), 7.10e7.40 (m, 11H, AreH), 7.84 (s, 1H, imidazole); ESI-MS
(m/z): Calcd. 529.26, found 530.4 (Mþ); Anal. Calcd. (%) for
(100 MHz, DMSO-d6) d: 13.6 (CH3), 14.9 (CH3), 25.0, 27.5 (2C, CH3),
28.8 (C4), 32.1 (C(CH3)2), 41.6, 49.7 (2(CH2)2), 58.5 (OCH2), 76.5 (Ce
COOEt), 110.3, 121.9, 122.4, 122.5, 127.5, 128.9, 128.9, 129.1, 130.3,
138.1, 139.5, 139.9, 148.1, 150.1, 153.1, (15C, AreC), 169.1 (COOEt),
C
32H31N7O:72.57; H, 5.90; N, 18.51. Found: C, 72.42; H, 5.79; N,
18.69.
196.1 (C]O); 1H NMR (400 MHz, DMSO-d6):
d
0.83 (s, 3H, CH3),
6.1.3.2. Ethyl 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-7,7-dimethyl-5-oxo-1-p-tolyl-1,4,5,6,7,8-
hexahydroquinoline-3-carboxylate (8b). Yield 79%; m.p. 247 ꢂC; IR
(KBr, nmax, cmꢀ1): 3418 & 3362 (asym. & sym. stretching of eNH2),
2961 (Ar CeH), 2930 (CeH asym. stretching of CH2 group), 1645
(C]O stretching), 1372 (eCH3 stretching); 13C NMR (100 MHz,
d 0.88 (s, 3H, CH3), d
0.95 (t, J ¼ 7.2 Hz, 3H, CH3), 1.72 (d, J ¼ 17.6 Hz,
1H, CH2), 1.97 (d, J ¼ 17.2 Hz, 1H, CH2), 2.17 (s, 2H, CH2), 2.40 (s, 3H,
CH3), 2.47 (s, 3H, CH3), 3.42 (m, 2H, CH2), 4.88 (s, 1H, CH), 6.76 (s,
2H, NH2), 6.93e7.43 (m, 11H, AreH), 7.89 (s, 1H, imidazole); ESI-MS
(m/z): Calcd. 596.2, found 597.0 (Mþ), 598.2 (Mþ2); Anal. Calcd. (%)
for C33H33ClN6O3 : C, 66.38; H, 5.57; N, 14.07. Found: C, 66.30; H,
5.44; N, 14.15.
DMSO-d6) d: 13.5 (CH3), 15.1 (CH3), 21.3 (CH3), 25.3, 27.8 (2C, CH3),
28.8 (C4), 32.2 (C(CH3)2), 41.7, 50.1 (2(CH2)2), 58.6 (OCH2), 76.4 (Ce
COOEt), 110.8, 122.4, 122.5, 122.6, 127.4, 129.3, 129.5, 131.2, 132.4,
133.7, 138.4, 139.8, 148.4, 150.7, 152.8, (15C, AreC), 169.3 (COOEt),
6.1.3.6. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(4-chlorophenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carboxamide (8f). Yield 72%; m.p. 245 ꢂC; IR
(KBr, nmax, cmꢀ1): 3414 & 3381 (asym. & sym. stretching of eNH2),
2947 (Ar CeH), 2932 (CeH asym. stretching of CH2 group), 1645
(C]O stretching), 1371 (eCH3 stretching); 13C NMR (100 MHz,
196.0 (C]O); 1H NMR (400 MHz, DMSO-d6):
d 0.81 (s, 3H, CH3),
d
0.86 (s, 3H, CH3),
d
0.95 (t, J ¼ 7.2 Hz, 3H, CH3), 1.70 (d, J ¼ 17.6 Hz,
1H, CH2), 1.94 (d, J ¼ 17.2 Hz, 1H, CH2), 2.14 (s, 2H, CH2), 2.41 (s, 3H,
CH3), 2.44 (s, 3H, CH3), 3.44 (m, 2H, CH2), 4.84 (s, 1H, CH), 6.70 (s,
2H, NH2), 6.96e7.40 (m, 11H, AreH), 7.86 (s, 1H, imidazole); ESI-MS
(m/z): Cacld. 576.28, found 577.2 (Mþ); Anal. Calcd. (%) for
DMSO-d6)
d: 13.5 (CH3), 26.9, 27.67 (2C, CH3), 28.8 (C4), 31.9
(C(CH3)2), 41.6, 49.7 (2(CH2)2),78.3 (CeCONH2), 109.5, 115.5, 119.9,
122.5, 127.7, 128.3, 129.7, 129.9, 129.9, 132.6, 136.0, 138.3, 148.1,
150.3, 150.9 (15C, AreC), 172.2 (CONH2), 195.6 (C]O); 1H NMR
C
34H36N6O3: C, 70.81; H, 6.29; N, 14.57. Found: C, 70.70; H, 6.17; N,
14.72.
(400 MHz, DMSO-d6):
d 0.83 (s, 3H, CH3), 0.86 (s, 3H, CH3), 1.75 (d,
6.1.3.3. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-7,7-dimethyl-5-oxo-1-p-tolyl-1,4,5,6,7,8-
hexahydroquinoline-3-carboxamide (8c). Yield 71%; m.p. 230 ꢂC; IR
(KBr, nmax, cmꢀ1): 3409 & 3371 (asym. & sym. stretching of e NH2),
2955 (Ar CeH), 2925 (CeH asym. stretching of CH2 group), 1641
(C]O stretching), 1375 (eCH3 stretching); 13C NMR (100 MHz,
J ¼ 17.2 Hz, 1H, CH2), 1.93 (d, J ¼ 17.2 Hz, 1H, CH2), 2.13 (s, 2H, CH2),
2.51 (s, 3H, CH3), 4.70 (s,1H, CH), 5.76 (s, 2H, NH2), 6.75 (s, 2H, NH2),
7.06e7.64 (m, 11H, AreH), 7.92 (s, 1H, imidazole); ESI-MS (m/z):
Calcd. 567.2, found 568.0 (Mþ), 569.3 (Mþ2); Anal. Calcd. (%) for
C
31H30ClN7O2:C, 65.54; H, 5.32; N,17.26. Found: C, 65.41; H, 5.24; N,
17.38.
DMSO-d6) d: 13.5 (CH3), 21.0 (CH3), 26.6, 27.6 (2C, CH3), 28.9 (C4),
32.1 (C(CH3)2), 41.8, 50.1 (2(CH2)2), 78.3 (CeCONH2), 109.6, 117.9,
119.7, 122.4, 128.5, 129.3, 129.9, 130.0, 132.3, 133.4, 136.5, 138.5,
147.9, 149.8, 151.1 (15C, AreC), 171.1 (CONH2), 195.7 (C]O); 1H NMR
6.1.3.7. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(4-hydroxyphenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8g). Yield 84%; m.p. 283 ꢂC; IR
(KBr, nmax, cmꢀ1): 3441 & 3361 asym. & sym. stretching of eNH2),
2945 (Ar CeH), 2926 (CeH asym. stretching of CH2 group), 2171
(C^N stretching), 1646(C]O stretching), 1375 (eCH3 stretching).
(400 MHz, DMSO-d6):
d 0.84 (s, 3H, CH3), 0.88 (s, 3H, CH3), 1.73 (d,
J ¼ 17.2 Hz, 1H, CH2), 1.96 (d, J ¼ 17.2 Hz, 1H, CH2), 2.16 (s, 2H, CH2),
2.44 (s, 3H, CH3), 2.51 (s, 3H, CH3), 4.69 (s, 1H, CH), 5.74 (s, 2H, NH2),
6.73 (s, 2H, NH2), 7.01e7.64 (m, 11H, AreH), 7.91 (s, 1H, imidazole);
ESI-MS (m/z): Calcd. 547.27, found 547.9 (Mþ); Anal. Calcd. (%) for
13C NMR (100 MHz, DMSO-d6)
d: 13.5 (CH3), 27.2, 28.3 (2C, CH3),
28.5 (C4), 32.4 (C(CH3)2), 41.6, 49.8 (2(CH2)2), 58.5 (CeCN), 108.1,
117.5, 118.7, 121.1, 122.6, 122.8, 127.9, 129.8, 130.0, 130.8, 135.3, 138.3,
147.4, 150.9, 151.6, 155.1 (16C, AreC), 195.6 (C]O); 1H NMR
C
32H33N7O2:C, 70.18; H, 6.07; N, 17.90. Found: C, 70.24; H, 5.95; N,
17.79.
(400 MHz, DMSO-d6):
d 0.87 (s, 3H, CH3), 0.90 (s, 3H, CH3), 1.77 (d,
6.1.3.4. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(4-chlorophenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8d). Yield 80%; m.p. 285 ꢂC; IR
(KBr, nmax, cmꢀ1): 3432 & 3356 (asym. & sym. stretching of e NH2),
2953 (Ar CeH), 2929 (CeH asym. stretching of CH2 group), 2187
J ¼ 17.2 Hz, 1H, CH2), 1.94 (d, J ¼ 17.2 Hz, 1H, CH2), 2.15 (s, 2H, CH2),
2.36 (s, 3H, CH3), 4.30 (s, 1H, CH), 5.50 (s, 2H, NH2), 7.13e7.66 (m,
11H, AreH), 7.77 (s, 1H, OH), 7.95 (s, 1H, imidazole); ESI-MS (m/z):
Calcd. 531.2, found 532.2 (Mþ); Anal. Calcd. (%) for C31H29N7O2:C,
70.04; H, 5.50; N, 18.44. Found: C, 70.21; H, 5.41; N, 18.49.

P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
213
6.1.3.8. Ethyl 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-1-(4-hydroxyphenyl)-7,7-dimethyl-5-oxo-
1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (8h). Yield 79%; m.p.
290 ꢂC; IR (KBr, nmax, cmꢀ1): 3415 & 3363 (asym. & sym. stretching
of eNH2), 2961 (Ar CeH), 2922 (CeH asym. stretching of CH2
group), 1641 (C]O stretching), 1372 (eCH3 stretching); 13C NMR
(d, J ¼ 17.2 Hz, 1H, CH2), 2.12 (s, 2H, CH2), 2.39 (s, 3H, CH3), 2.45 (s,
3H, CH3), 3.46 (m, 2H, CH2), 4.82 (s, 1H, CH), 6.72 (s, 2H, NH2), 6.98e
7.42 (m, 11H, AreH), 7.85 (s, 1H, imidazole); ESI-MS (m/z): Calcd.
562.3, found 563.3 (Mþ); Anal. Calcd. (%) for C33H34N6O3:C, 70.44;
H, 6.09; N, 14.94. Found: C, 70.21; H, 6.00; N, 15.06.
(100 MHz, DMSO-d6)
d
: 13.7 (CH3), 15.1 (CH3), 25.4, 28.0 (2C, CH3),
6.1.4.2. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-7,7-dimethyl-5-oxo-1-phenyl-1,4,5,6,7,8-
hexahydroquinoline-3-carboxamide (8l). Yield 81%; m.p. 235 ꢂC; IR
(KBr, nmax, cmꢀ1): 3411 & 3389 (asym. & sym. stretching of eNH2),
2948 (Ar CeH), 2932 (CeH asym. stretching of CH2 group), 1639
(C]O stretching), 1372 (eCH3 stretching); 13C NMR (100 MHz,
28.9 (C4), 32.0 (C(CH3)2), 41.9, 50.2 (2(CH2)2), 58.5 (OCH2), 76.3 (Ce
COOEt), 111.1, 117.6, 118.5, 122.1, 122.6, 127.4, 129.3, 130.1, 138.3,
139.3, 139.4, 148.0, 150.1, 152.8, 156.9 (15C, AreC), 169.4 (COOEt),
196.2 (C]O); 1H NMR (400 MHz, DMSO-d6):
d
0.82 (s, 3H, CH3),
d
0.88 (s, 3H, CH3), d
0.93 (t, J ¼ 7.2 Hz, 3H, CH3), 1.69 (d, J ¼ 17.6 Hz,
1H, CH2), 1.96 (d, J ¼ 17.2 Hz, 1H, CH2), 2.13 (s, 2H, CH2), 2.42 (s, 3H,
CH3), 2.47 (s, 3H, CH3), 3.44 (m, 2H, CH2), 4.86 (s, 1H, CH), 6.73 (s,
2H, NH2), 6.95e7.42 (m, 11H, AreH), 7.87 (s, 1H, imidazole), 7.93 (s,
1H, OH); MS: ESI-MS (m/z): Calcd. 578.3, found 578.1 (Mþ); Anal.
Calcd. (%) for C33H34N6O4:C, 68.49; H, 5.92; N, 14.52. Found: C,
68.41; H, 5.96; N, 14.52.
DMSO-d6) d: 13.6 (CH3), 26.8, 27.7 (2C, CH3), 28.9 (C4), 32.2
(C(CH3)2), 41.8, 50.0 (2(CH2)2),78.4 (CeCONH2), 109.7, 119.9, 121.6,
122.6, 127.7, 129.6, 129.8, 130.1, 130.5, 132.1, 136.5, 138.2, 148.1, 150.1,
150.9 (15C, AreC), 172.4 (CONH2), 195.7 (C]O); 1H NMR (400 MHz,
DMSO-d6):
d
0.82 (s, 3H, CH3), 0.86 (s, 3H, CH3), 1.71 (d, J ¼ 17.2 Hz,
1H, CH2), 1.95 (d, J ¼ 17.2 Hz, 1H, CH2), 2.15 (s, 2H, CH2), 2.47 (s, 3H,
CH3), 4.72 (s, 1H, CH), 5.76 (s, 2H, NH2), 6.78 (s, 2H, NH2), 6.98e7.61
(m, 12H, AreH), 7.93 (s, 1H, imidazole); ESI-MS (m/z): Calcd. 533.3,
found 534.0 (Mþ); Anal. Calcd. (%) for C31H31N7O2:C, 69.77; H, 5.86;
N, 18.37. Found: C, 70.03; H, 6.00; N, 18.18.
6.1.3.9. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(4-hydroxyphenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carboxamide (8i). Yield 73%; m.p. 248 ꢂC; IR
(KBr, nmax, cmꢀ1): 3412 & 3385 (asym. & sym. stretching of eNH2),
2950 (Ar CeH), 2929 (CeH asym. stretching of CH2 group), 1639
(C]O stretching), 1371 (eCH3 stretching); 13C NMR (100 MHz,
6.1.4.3. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(2-hydroxyphenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8m). Yield 84%; m.p. 264 ꢂC; IR
(KBr, nmax, cmꢀ1): 3440 & 3352 (asym. & sym. stretching of eNH2),
2953 (Ar CeH), 2915 (CeH asym. stretching of CH2 group), 2180
(C^N stretching), 1640(C]O stretching), 1370 (eCH3 stretching);
DMSO-d6)
d: 13.7 (CH3), 26.8, 27.8 (2C, CH3), 28.9 (C4), 32.3
(C(CH3)2), 41.9, 50.2 (2(CH2)2),78.6 (CeCONH2), 110.1, 112.6, 114.8,
120.0, 122.7, 130.1, 130.2, 130.6, 131.9, 136.6, 138.2, 148.3, 151.1, 151.4,
155.4 (15C, AreC), 172.4 (CONH2), 195.6 (C]O); 1H NMR (400 MHz,
DMSO-d6):
d
0.85 (s, 3H, CH3), 0.89 (s, 3H, CH3), 1.76 (d, J ¼ 17.2 Hz,
13C NMR (100 MHz, DMSO-d6)
d: 13.1 (CH3), 27.3, 28.1 (2C, CH3),
28.4 (C4), 32.5 (C(CH3)2), 41.5, 49.8 (2(CH2)2), 57.9 (CeCN), 108.4,
113.9, 118.3, 121.1, 121.2, 121.4, 122.3, 126.1, 127.3, 129.6, 129.9, 130.3,
134.8, 138.2, 147.7, 150.7, 151.1, 152.1 (18C, AreC), 196.0 (C]O); 1H
1H, CH2), 1.94 (d, J ¼ 17.2 Hz, 1H, CH2), 2.14 (s, 2H, CH2), 2.16 (s, 3H,
CH3), 4.65 (s, 1H, CH), 5.75 (s, 2H, NH2), 6.75 (s, 2H, NH2),7.12e7.66
(m, 11H, AreH), 7.89 (s, 1H, imidazole), 7.99 (s, 1H, OH); ESI-MS (m/
z): Calcd. 549.2, found 550 (Mþ); Anal. Calcd. (%) for C31H31N7O3:C,
67.74; H, 5.69; N, 17.84. Found: C, 67.69; H, 5.51; N, 17.91.
NMR (400 MHz, DMSO-d6):
d 0.86 (s, 3H, CH3), 0.92 (s, 3H, CH3),
1.78 (d, J ¼ 17.2 Hz,1H, CH2),1.94 (d, J ¼ 17.2 Hz,1H, CH2), 2.18 (s, 2H,
CH2), 2.35 (s, 3H, CH3), 4.34 (s, 1H, CH), 5.46 (s, 2H, NH2), 7.12e7.64
(m, 11H, AreH), 7.81 (s, 1H, imidazole), 8.12 (s, 1H, OH); ESI-MS (m/
z): Calcd. 531.2, found, 532.2 (Mþ); Anal. Calcd. (%) for
6.1.4.0. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-7,7-dimethyl-5-oxo-1-phenyl-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8j). Yield 85%; m.p. 289 ꢂC; IR
(KBr, nmax, cmꢀ1): 3429 & 3378 (asym. & sym. stretching of eNH2),
2958 (Ar CeH), 2923 (CeH asym. stretching of CH2 group),
2184(C^N stretching), 1639 (C]O stretching), 1371 (eCH3
C31H29N7O2:C, 70.04; H, 5.50; N, 18.44. Found: C, 69.89; H, 5.41; N,
18.29.
6.1.4.4. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(3-hydroxyphenyl)-7, 7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8n). Yield 71%; m.p. 270 ꢂC; IR
(KBr, nmax, cmꢀ1): 3429 & 3364 (asym. & sym. stretching of eNH2),
2961 (Ar CeH), 2925 (CeH asym. stretching of CH2 group), 2169
(C^N stretching), 1645(C]O stretching), 1373 (eCH3 stretching);
stretching); 13C NMR (100 MHz, DMSO-d6)
d: 13.3 (CH3), 27.1, 28.3
(2C, CH3), 28.6 (C4), 32.2 (C(CH3)2), 41.4, 49.8 (2(CH2)2), 58.9 (Ce
CN), 108.1, 120.0, 120.7, 121.3, 122.3, 122.4, 127.40, 129.5, 129.7, 130.1,
130.5, 134.8, 138.3, 147.1, 150.7, 151.1 (16C, AreC), 195.6 (C]O); 1H
NMR (400 MHz, DMSO-d6):
d 0.84 (s, 3H, CH3), 0.89 (s, 3H, CH3),
1.73 (d, J ¼ 17.2 Hz,1H, CH2),1.95 (d, J ¼ 17.2 Hz,1H, CH2), 2.16 (s, 2H,
CH2), 2.33 (s, 3H, CH3), 4.32 (s, 1H, CH), 5.46 (s, 2H, NH2), 7.05e7.68
(m, 12H, AreH), 7.84 (s, 1H, imidazole); ESI-MS (m/z): Cacld. 515.2,
found 515.3 (Mþ); Anal. Calcd. (%) for C31H29N7O:C, 72.21; H, 5.67;
N, 19.02. Found: C, 72.42; H, 5.79; N, 18.81.
13C NMR (100 MHz, DMSO-d6)
d: 13.4 (CH3), 27.5, 28.2 (2C, CH3),
28.6 (C4), 32.2 (C(CH3)2), 41.4, 49.7 (2(CH2)2),58.2 (CeCN), 107.6,
108.3, 108.4, 114.7, 121.2, 122.5, 123.1, 127.8, 129.6, 129.9, 130.2,
130.5, 134.7, 138.2, 147.3, 150.7, 151.1, 160.7 (18C, AreC), 195.4 (C]
O); 1H NMR (400 MHz, DMSO-d6):
d 0.87 (s, 3H, CH3), 0.90 (s, 3H,
CH3), 1.76 (d, J ¼ 17.2 Hz, 1H, CH2), 1.96 (d, J ¼ 17.2 Hz, 1H, CH2), 2.19
(s, 2H, CH2), 2.38 (s, 3H, CH3), 4.36 (s, 1H, CH), 5.46 (s, 2H, NH2),
7.09e7.66 (m, 11H, AreH), 7.84 (s, 1H, imidazole), 8.32 (s, 1H, OH);
ESI-MS (m/z): Cacld. 531.2, found 532.1 (Mþ); Anal. Calcd. (%) for
6.1.4.1. Ethyl
4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-7,7-dimethyl-5-oxo-1-phenyl-1,4,5,6,7,8-
hexahydroquinoline-3-carboxylate (8k). Yield 82%; m.p. 275 ꢂC; IR
(KBr, nmax, cmꢀ1): 3421 & 3373 (asym. & sym. stretching of eNH2),
2949 (Ar CeH), 2927 (CeH asym. stretching of CH2 group), 1645
(C]O stretching), 1373 (-CH3 stretching); 13C NMR (100 MHz,
C31H29N7O2:C, 70.04; H, 5.50; N, 18.44. Found: C, 69.93; H, 5.36; N,
18.25.
DMSO-d6)
d
: 13.2 (CH3), 15.2 (CH3), 25.3, 27.9 (2C, CH3), 28.9 (C4),
6.1.4.5. Ethyl 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-1-(3-hydroxyphenyl)-7,7-dimethyl-5-oxo-
1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (8o). Yield 69%; m.p.
282 ꢂC; IR (KBr, nmax, cmꢀ1): 3417 & 3383 (asym. & sym. stretching
of eNH2), 2963 (Ar CeH), 2932 (CeH asym. stretching of CH2
group), 1636 (C]O stretching), 1375 (eCH3 stretching); 13C NMR
32.4 (C(CH3)2), 41.8, 50.0 (2(CH2)2), 58.7 (OCH2), 76.6 (CeCOOEt),
110.1, 118.9, 122.3,122.4,122.8, 127.4, 128.9,129.1, 129.4, 139.1, 139.2,
139.5, 148.8, 151.0, 152.9, (15C, AreC), 169.3 (COOEt), 195.9 (C]O);
1H NMR (400 MHz, DMSO-d6):
CH3),
d
0.81 (s, 3H, CH3),
d 0.89 (s, 3H,
d
0.94 (t, J ¼ 7.2 Hz, 3H, CH3), 1.71 (d, J ¼ 17.6 Hz, 1H, CH2), 1.92

214
P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
(100 MHz, DMSO-d6)
d
: 13.8 (CH3), 15.0 (CH3), 25.4, 27.8 (2C, CH3),
(Mþ); Anal. Calcd. (%) for C34H36N6O4:C, 68.90; H, 6.12; N, 14.18.
Found: C, 68.81; H, 5.99; N, 14.32.
28.6 (C4), 32.5 (C(CH3)2), 41.7, 50.1 (2(CH2)2), 58.6 (OCH2), 76.5 (Ce
COOEt), 107.1, 108.2, 110.9, 116.2, 122.5, 123.0, 127.4, 127.6, 129.6,
129.7, 138.7, 138.9, 139.4, 148.5, 151.1, 153.01, 160.6 (17C, AreC),
6.1.4.9. Ethyl 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-1-(4-hydroxyphenyl)-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carboxylate (8s). Yield 78%; m.p. 281 ꢂC; IR
(KBr, nmax, cmꢀ1): 3422 & 3362 (asym. & sym. stretching of eNH2),
2964 (Ar CeH), 2926 (CeH asym. stretching of CH2 group), 1643
(C]O stretching), 1369 (-CH3 stretching); 13C NMR (100 MHz,
169.3 (COOEt), 196.9 (C]O); 1H NMR (400 MHz, DMSO-d6):
d
0.80
(s, 3H, CH3), d 0.87 (s, 3H, CH3), d
0.93 (t, J ¼ 7.2 Hz, 3H, CH3), 1.69 (d,
J ¼ 17.6 Hz, 1H, CH2), 1.93 (d, J ¼ 17.2 Hz, 1H, CH2), 2.13 (s, 2H, CH2),
2.40 (s, 3H, CH3), 2.44 (s, 3H, CH3), 3.43 (m, 2H, CH2), 4.86 (s, 1H,
CH), 6.69 (s, 2H, NH2), 6.93e7.41 (m, 11H, AreH), 7.86 (s, 1H,
imidazole), 8.26 (s, 1H, OH); ESI-MS (m/z): Calcd. 578.3, found 579.0
(Mþ); Anal. Calcd. (%) for C33H34N6O4 : C, 68.49; H, 5.92; N, 14.52.
Found: C, 68.66; H, 6.11; N, 14.35.
DMSO-d6) d: 13.6 (CH3), 15.2 (CH3), 21.3 (CH2), 28.9 (C4), 30.1, 38.5
(2(CH2)2), 58.6 (OCH2), 76.3 (CeCOOEt), 110.7, 117.2, 118.9, 122.3,
122.6,127.8,129.3,129.5,138.7,138.9,139.8,147.9,150.7,152.8,156.4
(15C, AreC), 169.1 (COOEt), 196.0 (C]O); 1H NMR (400 MHz,
6.1.4.6. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(3-hydroxyphenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carboxamide (8p). Yield 64%; m.p. 240 ꢂC; IR
(KBr, nmax, cmꢀ1): 3408 & 3369 (asym. & sym. stretching of eNH2),
2949 (Ar CeH), 2933 (CeH asym. stretching of CH2 group), 1642
(C]O stretching), 1372 (eCH3 stretching); 13C NMR (100 MHz,
DMSO-d6):
d
0.91 (t, J ¼ 7.2 Hz, 3H, CH3), 1.71 (d, J ¼ 17.6 Hz, 1H,
CH2),1.94 (d, J ¼ 17.2 Hz,1H, CH2), 2.15 (s, 2H, CH2), 2.42 (s, 3H, CH3),
2.45 (s, 3H, CH3), 3.47 (m, 2H, CH2), 4.85 (s, 1H, CH), 6.71 (s, 2H,
NH2), 6.94e7.43 (m, 11H, AreH), 7.90 (s, 1H, imidazole), 7.99 (s, 1H,
OH); ESI-MS (m/z): Calcd. 550.2, found 550.9 (Mþ); Anal. Calcd. (%)
for C31H30N6O4:C, 67.62; H, 5.49; N, 15.26. Found: C, 67.49; H, 5.62;
N, 15.20.
DMSO-d6)
d: 13.6 (CH3), 26.7, 27.8 (2C, CH3), 28.9 (C4), 32.3
(C(CH3)2), 42.0, 49.9 (2(CH2)2),78.5 (CeCONH2), 102.5, 107.1, 109.8,
113.9,120.1, 122.8,127.6, 129.9,130.2,130.3,131.5, 136.5,138.4,147.7,
150.2, 150.9, 156.9 (17C, AreC), 172.5 (CONH2), 195.6 (C]O); 1H
6.1.5. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(4-hydroxyphenyl)-5-oxo-1,4,5,6,7,8-
NMR (400 MHz, DMSO-d6):
d
0.83 (s, 3H, CH3), 0.87 (s, 3H, CH3),
hexahydroquinoline-3-carboxamide (8t)
1.73 (d, J ¼ 17.2 Hz,1H, CH2),1.93 (d, J ¼ 17.2 Hz,1H, CH2), 2.13 (s, 2H,
CH2), 2.17 (s, 3H, CH3), 4.70 (s, 1H, CH), 5.77 (s, 2H, NH2), 6.77 (s, 2H,
NH2),7.11e7.65 (m, 11H, AreH), 7.91 (s, 1H, imidazole), 8.29 (s, 1H,
OH); ESI-MS (m/z): Cacld. 549.2, found 550.2 (Mþ); Anal. Calcd. (%)
for C31H31N7O3:C, 67.74; H, 5.69; N, 17.84. Found: C, 67.73; H, 5.81;
N, 17.63.
Yield 73%; m.p. 240 ꢂC; IR (KBr, nmax, cmꢀ1): 3415 & 3385 (asym.
& sym. stretching of eNH2), 2960 (Ar CeH), 2923 (CeH asym.
stretching of CH2 group), 1641 (C]O stretching), 1374 (eCH3
stretching); 13C NMR (100 MHz, DMSO-d6)
d: 13.6 (CH3), 21.2 (CH2),
28.9 (C4), 30.3, 38.2 (2(CH2)2), 78.5 (CeCONH2), 109.9, 120.0, 112.7,
122.7,115.1,130.0,130.1,130.3,155.4,132.0,136.7,138.4,148.5,150.9,
151.3 (15C, AreC), 172.6 (CONH2), 195.9 (C]O); 1H NMR (400 MHz,
6.1.4.7. 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazol-4-
yl)-2-amino-1-(4-methoxyphenyl)-7,7-dimethyl-5-oxo-1,4,5,6,7,8-
hexahydroquinoline-3-carbonitrile (8q). Yield 82%; m.p. 278 ꢂC; IR
(KBr, nmax, cmꢀ1): 3450 & 3360 (asym. & sym. stretching of eNH2),
2949 (Ar CeH), 2931 (CeH asym. stretching of CH2 group), 2175
(C^N stretching), 1641(C]O stretching), 1372 (eCH3 stretching);
DMSO-d6):
d
1.67 (m, 2H, CH2), 1.92 (s, 3H, CH3), 1.98 (t, J ¼ 7.2 Hz,
2H, CH2), 2.95 (t, J ¼ 17.6 Hz, 2H, CH2), 4.76 (s, 1H, CH), 5.82 (s, 2H,
NH2), 6.78 (s, 2H, NH2),7.04e7.62 (m, 11H, AreH), 7.95 (s, 1H,
imidazole), 7.96 (s, 1H, OH); ESI-MS (m/z): Calcd. 521.2, found 522.0
(Mþ); Anal. Calcd. (%) for C29H27N7O3:C, 66.78; H, 5.22; N, 18.80.
Found: C, 66.94; H, 5.06; N, 18.71.
13C NMR (100 MHz, DMSO-d6)
d: 13.3 (CH3), 27.2, 28.2 (2C, CH3),
28.7 (C4), 32.3 (C(CH3)2), 41.6, 49.8 (2(CH2)2), 55.1 (OCH3), 58.1 (Ce
CN), 107.9, 119.4, 121.2, 121.3, 122.2, 122.6, 127.5, 129.6, 130.3, 130.7,
134.9, 138.6, 147.4, 150.7, 151.2, 156.3 (16C, AreC), 195.6 (C]O); 1H
7. Biological evaluation
7.1. In vitro antimicrobial assay
NMR (400 MHz, DMSO-d6):
d 0.85 (s, 3H, CH3), 0.91 (s, 3H, CH3),
1.75 (d, J ¼ 17.2 Hz,1H, CH2),1.93 (d, J ¼ 17.2 Hz,1H, CH2), 2.15 (s, 2H,
CH2), 2.38 (s, 3H, CH3), 3.58 (s, 3H, CH3), 4.33 (s, 1H, CH), 5.52 (s, 2H,
NH2), 7.09e7.70 (m, 11H, AreH), 7.84 (s, 1H, imidazole); ESI-MS (m/
z): Calcd. 545.3, found 546.1 (Mþ); Anal. Calcd. (%) for
The in vitro antimicrobial activity of all synthesized compounds
was carried out by broth microdilution method. 2% DMSO in water
was used as the diluent to get the desired concentration of com-
pounds to test upon standard bacterial strains. MuellereHinton
broth was used as nutrient medium to grow and dilute the com-
pound suspension for the test bacteria. Sabouraud Dextrose broth
was used for fungal nutrition. Inoculum size for test strain was
adjusted to 108 CFU mLꢀ1 by comparing the turbidity. Serial di-
lutions were prepared in primary and secondary screening. Each
synthesized compounds and the standard drugs were diluted
C
32H31N7O2:C, 70.44; H, 5.73; N, 17.97. Found: C, 70.23; H, 5.59; N,
18.07.
6.1.4.8. Ethyl 4-(5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyr-
azol-4-yl)-2-amino-1-(4-methoxyphenyl)-7,7-dimethyl-5-oxo-
1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (8r). Yield 79%; m.p.
249 ꢂC; IR (KBr, nmax, cmꢀ1): 3413 & 3369 (asym. & sym. stretching
of eNH2), 2959 (Ar CeH), 2930 (CeH asym. stretching of CH2
group), 1644 (C]O stretching), 1375 (eCH3 stretching); 13C NMR
obtaining 2000
which were found to be active in primary screening (i.e. 500, 250
and 200 g/mL concentrations) were further screened in their
second set of dilution at 100, 50, 25 and 12.5 g/mL concentration
mg/mL concentration as a stock solution. The drugs
m
(100 MHz, DMSO-d6)
d
: 13.6 (CH3), 14.9 (CH3), 25.3, 27.9 (2C, CH3),
m
28.9 (C4), 32.2 (C(CH3)2), 41.9, 49.9 (2(CH2)2), 55.6 (OCH3) 58.7
(OCH2), 76.8 (CeCOOEt),110.8,119.9,120.1,122.3,122.9,127.6,129.4,
129.5, 138.5,138.9,139.4, 148.4, 150.6, 153.1, 157.9 (15C, AreC), 169.2
against all microorganisms. 10 micro litre suspensions were further
inoculated on appropriate media and growth was noted after 24
and 48 h. The control tube containing no antibiotic was instanta-
neously subcultured (before inoculation) by spreading a loopful
evenly over an area of plate of medium suitable for the growth of
(COOEt), 196.8 (C]O); 1H NMR (400 MHz, DMSO-d6):
d
0.82 (s, 3H,
CH3),
d 0.85 (s, 3H, CH3), d
0.94 (t, J ¼ 7.2 Hz, 3H, CH3), 1.72 (d,
J ¼ 17.6 Hz, 1H, CH2), 1.96 (d, J ¼ 17.2 Hz, 1H, CH2), 2.14 (s, 2H, CH2),
2.39 (s, 3H, CH3), 2.42 (s, 3H, CH3), 3.45 (m, 2H, CH2), 3.55 (s, 3H,
CH3), 4.83 (s, 1H, CH), 6.72 (s, 2H, NH2), 6.97e7.44 (m, 11H, AreH),
7.88 (s, 1H, imidazole); ESI-MS (m/z): Calcd. 592.3, found 593.0
the test organism. The tubes were then put for incubation at 37 ꢂ
C
overnight. The highest dilution preventing appearance of turbidity
after spot subculture was considered as minimal inhibitory con-
centration (MIC,
m/L). All the tubes showing no visible growth

P.N. Kalaria et al. / European Journal of Medicinal Chemistry 78 (2014) 207e216
215
(same as control tube) were subcultured and incubated overnight
at 37 ꢂC. The amount of growth from the control tube before in-
cubation was compared. In this study Ampicillin, Norfloxacin and
Chloramphenicol were used as the standard antibacterial drugs.
Nystatin and Griseofulvin were used as standard antifungal drugs.
The results are summarized in Table 1.
screening of the compounds reported herein. PNK and SPS wish to
acknowledge the University Grants Commission e New Delhi, India
for meritorious fellowships awarded to them.
Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.ejmech.2014.02.015.
7.2. In vitro antituberculosis assay
The antitubercular activity of all synthesized compound against
M. tuberculosis H37Rv was performed by LowensteineeJensen
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concentration that inhibited 50% of parasite growth (IC50 value)
was determined by interpolation using Microcal Origin software.
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Acknowledgments
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