Synthesis, anticonvulsant and anti-inflammatory studies of new 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones

Article abstract of DOI:10.1016/j.ejmech.2013.10.010

The present work involves design and synthesis of new substituted 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones (4a-s, 5a-h), starting from 4-hydroxybenzaldehyde. The final compounds were screened for their in vivo anticonvulsant activity by MES, scPTZ and 6 Hz methods, while their anti-inflammatory screening was performed by Carrageenan induced Paw Edema method. The results indicated that compounds carrying electron donating groups are anticonvulsant active, while most of the tested compounds exhibited significant anti-inflammatory activity. Compounds 4k, l, 4p-s, and 5c showed rapid anti-inflammatory activity within 30 min and appeared as lead compounds. Further, Neurotoxicity study revealed that all the tested compounds are non-toxic up to 300 mg/kg doses. Selected compounds were also subjected to analgesic screening following Tail immersion method and they exhibited good activity.

Full text of DOI:10.1016/j.ejmech.2013.10.010

Accepted Manuscript
Synthesis, anticonvulsant and anti-inflammatory studies of new 1,4-dihydropyridin-4-
yl-phenoxyacetohydrazones
Shrikanth Ulloora, Ramakrishna Shabaraya, Rajesh Ranganathan, Airody Vasudeva
Adhikari
PII:
S0223-5234(13)00651-X
10.1016/j.ejmech.2013.10.010
EJMECH 6473
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 20 May 2013
Revised Date: 30 September 2013
Accepted Date: 4 October 2013
Please cite this article as: S. Ulloora, R. Shabaraya, R. Ranganathan, A.V. Adhikari, Synthesis,
anticonvulsant and anti-inflammatory studies of new 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones,
European Journal of Medicinal Chemistry (2013), doi: 10.1016/j.ejmech.2013.10.010.
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ACCEPTED MANUSCRIPT
H
N
R1
O
O
N
= H, Me
R1
R2
= Alkyl, alkoxy, aryl, OH, NH2, F, Cl, Br
R2
EtOOC
COOEt
N
H
New DHPs carrying hydrazone pharmacophore have been synthesized as new anticonvulsant
and anti-inflammatory agents. Many tested compounds showed good activity and are found
to be non-toxic in nature.

ACCEPTED MANUSCRIPT
Synthesis, anticonvulsant and anti-inflammatory studies of new 1,4-
dihydropyridin-4-yl-phenoxyacetohydrazones
Shrikanth Ullooraa, Ramakrishna Shabarayab, Rajesh Ranganathanc, Airody Vasudeva
Adhikaria*
aDepartment of Chemistry, National Institute of Technology Karnataka, Surathkal,
Mangalore 575 025, Karnataka, India
bSrinivas College of Pharmacy, Valachil, Mangalore, Karnataka, India
cNeuroscience centre, National Institute of Health, Bethesda, MD 20892-9020, USA
*Corresponding Author: Professor, Department of Chemistry, National Institute of
Technology Karnataka, Surathkal, Mangalore 575 025, Karnataka, India.
Tel.: +918242474000, Ext: 3203; Fax: +918242474033.
Email addresses: avachem@gmail.com, avadhikari123@yahoo.co.in, avchem@nitk.ac.in
Abstract:
The present work involves design and synthesis of new substituted 1,4-
dihydropyridin-4-yl-phenoxyacetohydrazones
(4a-s,
5a-h),
starting
from
4-
hydroxybenzaldehyde. The final compounds were screened for their in vivo anticonvulsant
activity by MES and scPTZ methods, while their anti-inflammatory screening was performed
by Carrageenan induced Paw Edema method. The results indicated that compounds carrying
electron donating groups are anticonvulsant active, while most of the tested compounds
exhibited significant anti-inflammatory activity. Compounds 4k-l, 4p-s, and 5c showed rapid
anti-inflammatory activity within 30 minutes and appeared as lead compounds. Further,
Neurotoxicity study revealed that all the tested compounds are non-toxic up to 300 mg/kg
doses. Selected compounds were also subjected to analgesic screening following Tail
immersion method and they exhibited good activity.
Key words: Dihydropyridine; Hydrazone; Anticonvulsant; Anti-inflammatory; Analgesic;
Neurotoxicity.
1. Introduction
Epilepsy is a major neurological disorder that accounts for 1% of global burden of
disease and affects more than 50 million people, all over the world [1]. Even though epilepsy
is known to mankind for several thousands of years, rapid advances both in diagnosis and
management have been made only in last few decades. Presently, there are many
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anticonvulsant drugs are available in the market that deals with control of disease.
Nevertheless, about 30% of patients are pharmaco-resistant to available drugs and
consequently, these patients experience uncontrolled seizures [2]. Moreover, present
antiepileptic treatment demands continuous medication for years together that brings about
many side effects [3]. According to literature, some of the available active anti-epileptic
drugs do not link with any binding site of the receptor [4], where as many other drugs show
their effect via different mechanism of actions [5]. As a result, identification of new
therapeutic agents that are devoid of any side effects, with a known mechanism of action has
become an active area of research, today in medicinal chemistry.
Dihydropyridines (DHPs) are the largest and most studied calcium channel blockers.
In addition to their clinical utility as Ca2+ channel blockers, they are also used extensively as
tools for study of voltage activated calcium channel structure and function [6]. It is well
established that calcium is an important factor responsible for induction of convulsive
seizures [7]. As a result, Ca2+ channel blockers are significant in controlling the convulsion
[8]. In this context, many DHPs are well documented in literature as potential anticonvulsant
agents [9, 10]. Further, literature reports support that DHP derivatives are potent anti-
inflammatory agents [11-13]. Interestingly, they were found to bind adenosine receptors (A1,
A2, A3) effectively in the brain and bring about therapeutic effects [14]. In fact, A3 adenosine
receptor antagonists are being sought as potential anti-inflammatory agents [15]. In our
previous study [16] also, good anti-inflammatory activity was observed for new DHPs
carrying amide pharmacophore. This clearly shows that DHP is a suitable heterocyclic
scaffold for the development of new antiepileptic and anti-inflammatory agents.
Hydrazones containing azomethine (–NHN=CH) protons constitute a vital class of
compounds for new drug development [17]. Several heterocyclic hydrazones were reported to
possess various biological activities viz. anticonvulsant [18], anti-inflammatory [19, 20],
analgesic [21], anti-candida [22], anti-tubercular [23, 24], antimicrobial [25], anticancer [26],
anti-proliferative [27] and antiamoebic [28] activities. Particularly, hydrazone moiety
attached to heterocyclic systems was shown to offer enhanced activity [29, 30]. Interestingly,
aryl hydrazones with terminal electron donating groups possess enhanced hydrogen bonding
capabilities which influence their biological activity significantly [31]. Against this
background, it has been planned to design and synthesize new dihydropyridine derivatives
carrying aromatic hydrazone as an important pharmacophore at C4 position of DHP through
an aryl linker, and to investigate their anticonvulsant as well as anti-inflammatory properties.
Further, most of the reported NSAIDs are exhibiting both anti-inflammatory and analgesic
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activities. Since their mode of actions are almost same, it has been also contemplated to
screen selected target compounds of the present work for in vivo analgesic property.
A detailed literature reports on structure-activity relationship study of 1,4-DHP
system revealed that unsubstituted free NH group in DHP ring is crucial for its better activity
with respect to any medicinal property. Further, presence of methyl groups at 2nd and 6th
positions, ester groups at 3rd and 5th positions and an aryl ring at 4th position are essential
structural features for prominent biological effect [32, 33]. Based on these observations, new
dihydropyridine derivatives carrying azomethine group have been designed as shown in
Figure 1. Different aryl rings with various substituents have been incorporated in our new
design in order to study the effect of substituents on their pharmacological activity.
Figure 1: Design of new dihydropyridine derivatives
2. Results and discussion:
2.1. Chemistry
All the intermediates and target compounds 4a-s and 5a-h were synthesized according
to Scheme 1. Required dihydropyridine derivative 1 was constructed following Hantzsch
method, from 4-hydroxybenzaldehyde by refluxing it with two equivalents of ethyl
acetoacetate and ammonium acetate under ethanol medium. The hydroxyl group was
alkylated with ethyl chloroacetate in DMF medium under nitrogen atmosphere to obtain the
product 2. Under similar mild conditions, only phenolic OH group, but not NH group of DHP
ring undergoes alkylation. The resulting ester 2 was converted to its hydrazide 3 through
nucleophilic substitution reaction by refluxing it with hydrazine hydrate in ethanol for about
4 hrs. Interestingly, stable ester groups on DHP ring remained intact under this condition. The
target hydrazones 4a-s and 5a-h were obtained by condensing hydrazide 3 with various
aldehydes and ketones, in ethanol medium with trace of conc. sulphuric acid as catalyst.
Scheme 1: Synthesis of intermediates and final compounds 4a-s and 5a-h
1
Newly synthesized target compounds were characterized by FTIR, H NMR, 13C
NMR and mass spectral techniques followed by elemental analysis. Formation of DHP ring
was confirmed by FTIR spectrum of 1, where it showed prominent peaks at 3337 cm-1 and
1656 cm-1, due to NH/OH and ester groups, respectively. This was further confirmed by its
1H NMR spectrum, where it displayed singlets at δ 9.09 and δ 8.77 ppm, which are attributed
to phenolic OH and NH proton of DHP ring, respectively. The presence of two ester groups
1
were confirmed by its H NMR spectrum, where in it showed multiplet and triplet at δ 4.04
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and δ 1.15 ppm, respectively for ester OCH2CH3 group. Appearance of a singlet at δ 4.74
ppm that corresponds to C4 CH proton further confirms the proposed structure of the product.
1
In H NMR spectrum of compound 2, disappearance of OH peak at δ 9.09 ppm clearly
established that phenolic hydroxyl group was alkylated but not NH group of DHP ring. In
FTIR spectrum of hydrazide 3, shifting of carbonyl stretching frequency from 1739 cm-1 to
1
lower frequency 1656 cm-1 indicated the formation of 3. Further, its H NMR spectrum
displayed two singlets at δ 9.24 and δ 4.28 ppm confirming the presence of hydrazidic NH
and NH2 groups. Formation of various hydrazones 4a-s and 5a-h from hydrazide 3 was
1
evidenced by their FTIR and 1H NMR spectra. H NMR spectrum of 4a showed a new peak
at δ 7.89 ppm which corresponds to –N=CH- proton, in the place of a singlet at δ 4.28 ppm
1
confirming its structure. Further, in H NMR spectrum of 5a appearance of new peak at δ
2.31 ppm which corresponds to allylic methyl group, is the proof for its formation. Similar
pattern of peaks were observed for remaining compounds of the series. Furthermore,
13
structures of all the final compounds were confirmed by their C NMR, mass spectral and
elemental data.
2.2. Biological results
2.2.1 Anticonvulsant and toxicity studies
The preclinical discovery and development of a new bioactive chemical entity for the
treatment of epilepsy depends heavily on the use of predictable animal models. The maximal
electroshock (MES) [34] and subcutaneous pentylenetetrazole (scPTZ) [35] screening
methods are the two important and routinely used in vivo animal models for the
anticonvulsant studies [36]. They are claimed to detect new bioactive chemical entities
affording protection to generalized tonic-clonic seizures and generalized absence seizures,
respectively. Further, Rotarod method [37] is an effective route for detecting motor
impairment of the new compounds. In this context, we also screened newly synthesized
molecules following these methodologies. Amongst twenty seven new derivatives, only eight
derivatives exhibited antiepileptic activity in MES method, while all the derivatives were
found to be inactive in scPTZ method. The screening results of active target compounds are
summarized in Table 1. Additionally, the MES active compounds were further screened by 6
Hz method [38] and these results are summarized in Table 2. These animal studies were
performed in accordance with the ethical standards on animal experimentations.
The screening results clearly show that the hydrazone group carrying an electron rich
aryl moiety is an essential structural feature for good anticonvulsant activities. The active
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compounds 4e, 4i-k, 4p, 5c, 5f and 5h exhibit their activities 4 hour post i.p. injection of test
samples, where as they are inactive at 0.5 hour. Amongst arylhydroxy derivatives, compound
4e containing 4-hydroxy substituent display prominent activity at 100 mg/kg dose. However,
its ortho-hydroxyphenyl analogue 4f is inactive even at high test dose of 300 mg/kg. It may
be due to the steric hindrance offered by the ortho hydroxyl group on aryl ring, which can
result in poor interaction of pharmacophore with the receptor. Similarly, 2,4-dihydroxyphenyl
derivative 4q does not show any activity. Based on these observations, it can be concluded
that a p-hydroxyphenyl group attached to hydrazone linkage is an activity enhancing moiety.
Further, it is observed that presence of an electron donating methoxy group adjacent to
hydroxy functionality (as in 4j) does not influence on the activity of 4e. However,
replacement of methoxy by ethoxy as in 4h causes loss of activity. This could be probably
due to steric effect exerted by the bulky ethoxy group. Also, a hydroxynaphthalene derivative
4p show activity at a dose of 100 mg/kg, confirming the importance of hydroxyl group in
enhancing the activity.
It is also observed that the presences of electron rich aryl systems like 4-methyl
phenyl (4i), indole (4k, 5c) display activity at 4 hours at a dose of 300 mg/kg. Interestingly,
4-fluorophenyl derivative 5f exhibit significant activity at 100 mg/kg dose. However,
replacement of fluoro by chloro as in 5h makes it less potent (300 mg/kg) while the bromo
derivative 5d is found to be inactive. Thus, as the size of halogen increases, their
anticonvulsant activity follows in the reverse order. Moreover, the active samples show
significant activity only in MES method but not in scPTZ mode, at all tested doses. This
clearly shows that new DHP derivatives are capable of preventing seizure spread effectively.
Finally, based on the activity profile, selected active compounds, viz. 4e, 4j, 4p, 5c and 5f
were subjected to 6 Hz screening study at a dose of 100 mg/kg. All these tested compounds
except 5c exhibit activity in 6 Hz method within one hour.
The Rotarod toxicity measurement study is an important route for the establishment of
toxicity profile of a newly synthesized compound. In our study, all the final compounds were
screened for their toxicity study by taking 30, 100 and 300 mg/kg doses. Interestingly, none
of the tested compounds displayed neurotoxicity up to 300 mg/kg. This clearly shows that
incorporation of hydrazone pharmacophore into dihydropyridine scaffold will not induce
toxicity on the resulting molecules. Thus, the active derivatives of the present series can be
concluded as non-toxic antiepileptic agents.
Table 1: Anticonvulsant and toxicity screening results of active compounds
5

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Table 2: Anticonvulsant activity of selected samples in 6 Hz screening method
2.2.2 Anti-inflammatory and analgesic studies
The results of anti-inflammatory activity (Table 3) clearly indicated that almost all
newly synthesized final compounds are quite active when compared to standard. It is
observed that DHP derivatives with electron donating substituents on aryl ring showed better
medicinal efficacy than those with electron withdrawing substituents. Interestingly,
compounds 4f, 4p, 4q and 4r with hydroxyl substituent, 4k and 5c carrying indole ring, 4l
and 5b involving thiophene system, 4s and 5f with halogen substituents exhibited good
activity. Further, compounds 4k-l, 4p-s, and 5c displayed very good anti-inflammatory
activity even better than that of standard drug diclofenac sodium. It is exciting to note that
these compounds showed superior activity soon after injection of Carrageenan irritant, i.e.
within half an hour.
Amongst the hydroxyl substituted derivatives, 2-hydroxy compound 4f exhibited
more activity than 4-hydroxy analogue 4e. Here the increased activity is probably due to the
crucial role played by o-hydroxybenzene moiety, which would involve in chelation with ions
along with hydrazone group at the vicinity of receptor [39]. Further, 4q with two hydroxyl
groups displayed the highest activity which may be attributed to the fact that the distance
between two hydroxyl groups is comparable with the distance between two functional groups
of salicylic acid and acetyl salicylate (Aspirin), so that it can bind to the same receptor site to
equal extent [40]. An interesting observation is that compound 4j carrying electron donating
methoxy group adjacent to hydroxyl moiety showed better activity than compound 4e, while
ethoxy substituted compound 4h displayed less activity, which may be due to steric effect
played by the bulky group. This was further confirmed by the result of compound 4d, where
presence of two methoxy groups offered low activity [41].
The influence of halogen attached to aryl group on biological activity is noteworthy
[42]. The results clearly indicate that compounds 4r, 4s and 5f with bromo and fluoro
substituents showed excellent activity, while 5d, 5f, and 5h carrying bromo, fluoro and
chloro groups, respectively displayed the activity in the decreasing order, 5f > 5h > 5d. The
variation in the activity may be owing to difference in the size of halogens. But, presence of
nitro group as in 4c and 5a reduced the activity to a considerable extent. Despite the presence
of nitro substituent, molecule 4o showed excellent activity, which may be because of the
presence of electron donating furan ring.
6

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Results of analgesic studies (Table 4) of five potent anti-inflammatory agents, viz. 4e,
4f, 4k, 4q, 5c revealed that compound 4f with 2-hydroxy substituent showed better activity
than 4e, containing 4-hydroxy analogue. Compound 4q with 2,4-dihydroxy substituent and 5c
with indole ring demonstrated excellent analgesic property. In conclusion, compounds 4q and
5c have emerged as lead compounds both in the anti-inflammatory and analgesic studies.
Table 3: Anti-inflammatory activity data of compounds 4a-s and 5a-h
Table 4: Analgesic activity data of selected hydrazones
3. Conclusion
In the present work, twenty seven new DHP derivatives were designed, synthesized
and characterized using spectral and elemental analyses. Their in vivo anticonvulsant, anti-
inflammatory and analgesic properties were investigated by standard methodologies. DHPs
carrying electron rich aryl groups exhibited moderate antiepileptic activity. Interestingly,
compounds 4k, 5c, 4l, 4p, 4q, 4r, 4s, and 5f containing indole, thiophene, arylhydroxy,
haloaryl as active groups displayed potential anti-inflammatory activity. Particularly,
compounds 4k-l, 4p-s, and 5c showed rapid anti-inflammatory activity within 30 minutes.
Active anti-inflammatory agents 4e, 4f, 4k, 4q and 5c were further studied for their in vivo
analgesic property, wherein compounds 4q and 5c containing hydroxylphenyl and indole
moieties exhibited prominent activity. The neurotoxicity study clearly revealed that all the
tested compounds are non-toxic up to 300 mg/kg and so, new compounds can be considered
as good templates for further developmental studies.
4. Experimental
4.1 Chemistry
All the chemicals used in the present work procured from Sigma Aldrich and
Lanchaster (UK). All the solvents are of analytical grade. They were purchased and used as
such without any further purification. The progress of the reaction was monitored by thin
layer chromatography, performed on a Silica gel 60 F254 coated aluminium sheet. Melting
points were determined on open capillaries using a Stuart SMP3 (BIBBY STERLIN Ltd. UK)
apparatus. Infrared spectra of all intermediate compounds and final molecules were recorded
1
on a Nicolet Avatar 5700 FTIR (Thermo Electron Corporation). H NMR and 13C NMR
spectra were obtained with Bruker-400 MHz and 100 MHz FT-NMR spectrometers,
respectively using TMS as internal reference and DMSO-d6 as solvent. Elemental analyses
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were performed on a Flash EA1112 CHNS analyzer (Thermo Electron Corporation). Mass
spectra were recorded on LC-MSD-Trap-XCT_Plus Mass Spectrometer.
4.1.1 Procedure for synthesis of diethyl 4-(4-hydroxyphenyl)-2,6-dimethyl-1,4-
dihydropyridine-3,5-dicarboxylate (1): A mixture of 4-hydroxybenzaldehyde (2 g, 16.3
mmol) ethyl acetoacetate (2.1 mL, 32.7 mmol) and ammonium acetate (1.9 g, 24.5 mmol) in
20 mL of ethanol was refluxed for 12 hrs. The reaction mixture was cooled on ice bath and
solid separated was filtered, washed with ethanol and dried under vacuum. The product was
o
recrystallized using ethanol/DMF mixture. Yield 60%, m.p. 239-241 C. FTIR (ATR, cm-1):
1
3337, 2980, 1656, 1221. H NMR (DMSO-d6, 400 MHz, δ ppm): 9.09 (s, 1H), 8.77 (s, 1H),
6.93 (d, 2H, J=12 Hz), 6.58 (d, 2H, J=12 Hz), 4.74 (s, 1H), 3.96 (m, 4H), 2.23 (s, 6H), 1.13
(t, 6H, 8.0 Hz). MS (m/z): 346.4. Anal. Calcd. for C19H23NO5: C, 66.07; H, 6.71; N, 4.06.
Found: C, 65.94; H, 6.69; N, 4.05.
4.1.2 Procedure for synthesis of diethyl 4-(4-(2-ethoxy-2-oxoethoxy)phenyl)-2,6-dimethyl-1,4-
dihydropyridine-3,5-dicarboxylate (2): To a clear solution of 1 (3 g, 8.7 mmol) in 30 mL of
DMF, ethyl chloroacetate (1.1 mL, 9.01 mmol) and K2CO3 (2.4 g, 17.3 mmol) were added
with stirring. The reaction mixture was stirred at 80 °C for 20 hrs under nitrogen and cooled
to room temperature. It was then quenched to ice cold water with stirring. Resulting solid
was filtered, washed with water and dried. This was recrystallized with hot ethanol. Yield
o
1
80%, m.p. 105-107 C. FTIR (ATR, cm-1): 3351, 2979, 2905, 1739, 1686, 1221. H NMR
(DMSO-d6, 400 MHz, δ ppm): 8.73 (s, 1H), 7.03 (d, 2H, J=6.8 Hz), 6.73 (d, 2H, J=6.8 Hz),
4.78 (s, 1H), 4.66 (s, 2H), 4.13 (m, 2H), 3.96 (m, 4H), 2.23 (s, 6H), 1.18 (t, 3H, J=7.2 Hz),
1.12 (t, 3H, J=6.8 Hz). MS (m/z): 432.2. Anal. Calcd. for C23H29NO7: C, 64.02; H, 6.77; N,
3.25. Found: C, 63.88; H, 6.74; N, 3.23.
4.1.3 Procedure for synthesis of 2-(4-(3,5-bis(ethoxycarbonyl)-2,6-dimethyl-1,4-
dihydropyridin-4-yl)phenoxy) acetic acid hydrazide (3): To a clear solution of 2 (2.5 g, 5.8
mmol) in ethanol (25 mL), hydrazine hydrate (0.5 mL, 10 mmol) was added and the mixture
was refluxed for 4 hrs. It was then cooled to room temperature to get crude hydrazide 3. The
resulting solid was filtered, washed with ethanol and recrystallized from ethanol/DMF
o
mixture. Yield 90%, m.p. 191-193 C. FTIR (ATR, cm-1): 3348, 3228, 3224, 3099, 2978,
1672, 1656, 1203. 1H NMR (DMSO-d6, 400 MHz, δ ppm): 9.24 (s, 1H), 8.73 (s, 1H), 7.03 (d,
2H, J=8.8 Hz), 6.76 (d, 2H, J=8.8 Hz), 4.78 (s, 1H), 4.39 (s, 2H), 4.28 (s, 2H), 3.97 (m, 4H),
8

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2.23 (s, 6H), 1.12 (t, 6H, J=7.0 Hz). MS (m/z): 418.1. Anal. Calcd. for C21H27N3O6. C, 60.42;
H, 6.52; N, 10.07. Found: C, 60.32; H, 6.50; N, 10.05.
4.1.4 General procedure for synthesis of hydrazones (4a-s, 5a-h): To a clear solution of 3
(0.5 g, 1.2 mmol) in ethanol (10 mL), 1.2 mmol of aldehyde / ketone was added and refluxed
for 8 hrs. Catalytic amount (0.2 mL) of glacial acetic acid was used for the synthesis of 5a-h.
Resulting solid was filtered, washed with ethanol and finally recrystallized with
methanol/chloroform mixture. The characterization and spectral data of final compounds are
given below.
4.1.4.1 Diethyl 4-(N'-(3,4,5-trimethoxybenzylidene)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydropyridine-3,5-dicarboxylate (4a): Yield 88%, m.p. 212-214 C. FTIR (ATR, cm-
1
1): 3352, 3000, 2941, 1663, 1620, 1492, 1211. H NMR (DMSO-d6, 400 MHz, δ in ppm):
11.47 (s, 1H, CONH), 8.72 (s, 1H, NH), 7.89 (s, 1H, CH), 7.07-6.72 (m, 6H, ArH), 5.06 (s,
1H, CH), 4.79 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 3.79 (s, 6H, OCH3), 3.68 (s, 3H, OCH3),
2.23 (s, 6H, CH3), 1.13 (t, 6H, CH3, J=8.2 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm):
169.2, 168.3, 157.3, 148.8, 145.1, 136.4, 131.4, 126.8, 125.4, 119.7, 116.5, 112.2, 102.4,
68.7, 62.5, 56.7, 43.3, 18.4, 16.3. MS (m/z) 596.1. Anal. Calcd. for C31H37N3O9: C, 62.51; H,
6.26; N, 7.05. Found: C, 62.40; H, 6.23; N, 7.02.
4.1.4.2 Diethyl 4-(N'-(4-chloro benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4b): Yield 90%, m.p. 246-248 C. FTIR (ATR, cm-1):
1
3285, 3231, 3058, 2957, 1660, 1610, 1217. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.2
(s, 1H, CONH), 8.73 (s, 1H, NH), 7.97 (s, 1H, CH), 7.71 (d, 2H, ArH, J=7.2 Hz), 7.50 (d,
2H, ArH, J=7.2 Hz), 7.06 (d, 2H, ArH, J=8.8 Hz), 6.81 (d, 2H, ArH, J=8.8 Hz), 5.09 (s, 1H,
CH), 4.79 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.33 (s, 6H, CH3), 1.12 (t, 6H, CH3, J=8.4 Hz).
13C NMR (DMSO-d6, 100 MHz, δ ppm): 169.4, 163.4, 158.7, 145.3, 136.7, 134.6, 132.0,
127.1, 123.2, 119.1, 116.5, 112.4, 101.9, 68.7, 62.9, 43.2, 18.1, 16.5. MS (m/z) 540.1. Anal.
Calcd. for C28H30ClN3O6: C, 62.28; H, 5.60; N, 7.78. Found: C, 62.21; H, 5.58; N, 7.75.
4.1.4.3 Diethyl 4-(N'-(4-nitro benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4c): Yield 91%, m.p. 244-246 C. FTIR (ATR, cm-1):
1
3309, 3237, 1667, 1608, 1224. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.80 (s, 1H,
CONH), 8.73 (s, 1H, NH), 8.09 (s, 1H, CH), 8.28-6.75 (m, 8H, ArH), 5.09 (s, 1H, CH), 4.79
(s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.13 (t, 6H, CH3, J=7.8 Hz). 13C NMR
(DMSO-d6, 100 MHz, δ ppm): 169.2, 163.7, 161.4, 146.7, 135.7, 134.2, 132.4, 127.3, 123.4,
9

ACCEPTED MANUSCRIPT
118.5, 116.5, 112.9, 101.9, 68.7, 63.1, 43.2, 18.1, 16.5. MS (m/z) 551.2. Anal. Calcd. for
C28H30N4O8. C, 61.08; H, 5.49; N, 10.18. Found: C, 60.97; H, 5.49; N, 10.14.
4.1.4.4 Diethyl 4-(N'-(3,4-dimethoxy benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydropyridine-3,5-dicarboxylate (4d): Yield 92%, m.p. 213-215 C. FTIR (ATR, cm-
1
1): 3230, 3094, 2969, 1667, 1612, 1496, 1221, 1122. H NMR (DMSO-d6, 400 MHz, δ in
ppm): 11.35 (s, 1H, CONH), 8.72 (s, 1H, NH), 7.95 (s, 1H, CH), 7.29-6.72 (m, 7H, ArH),
5.04 (s, 1H, CH), 4.78 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 3.78 (s, 3H, OCH3), 3.76 (s, 3H,
13
OCH3), 2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3, J=7.6 Hz). C NMR (DMSO-d6, 100 MHz, δ
ppm): 172.4, 165.2, 161.4, 158.4, 146.5, 134.7, 131.8, 123.4, 120.4, 118.5, 117.2, 102.8,
69.1, 62.3, 58.4, 43.2, 18.2, 16.5. MS (m/z) 566.6. Anal. Calcd. for C30H35N3O8. C, 63.70; H,
6.24; N, 7.43. Found: C, 63.57; H, 6.24; N, 7.41.
4.1.4.5 Diethyl 4-(N'-(4-hydroxy benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4e): Yield 87%, m.p. 237-239 C. FTIR (ATR, cm-1):
1
3384, 3282, 3224, 1662, 1609, 1222. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.28 (s,
1H, CONH), 9.44 (s, 1H, NH), 8.72 (s, 1H, CH), 7.86 (s, 1H, OH), 7.25-6.71 (m, 8H, ArH),
5.02 (s, 1H, CH), 4.79 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3,
J=8.0 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 170.4, 164.2, 161.4, 158.4, 146.8, 134.7,
132.4, 127.3, 123.4, 118.5, 117.2, 102.4, 69.1, 62.8, 43.2, 18.2, 16.5. MS (m/z) 522.3. Anal.
Calcd. for C28H31N3O7. C, 64.48; H, 5.99; N, 8.06. Found: C, 64.39; H, 5.95; N, 8.02.
4.1.4.6 Diethyl 4-(N'-(2-hydroxy phenyl)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4f): Yield 92%, m.p. 270-272 C. FTIR (ATR, cm-1):
1
3354, 3280, 3225, 1657, 1614, 1218. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.04 (s,
1H, CONH), 8.73 (s, 1H, NH), 8.53 (s, 1H, OH), 8.28 (s, 1H, CH), 7.68-6.73 (m, 8H, ArH),
5.01 (s, 1H, CH), 4.79 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3,
J=8.8 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 168.7, 166.9, 157.3, 148.3, 145.0, 136.3,
131.1, 126.4, 119.3, 116.2, 113.7, 101.9, 66.5, 58.9, 43.2, 18.1, 14.1. MS (m/z) 522.2. Anal.
Calcd. for C28H31N3O7. C, 64.48; H, 5.99; N, 8.06. Found: C, 64.40; H, 5.92; N, 8.03.
4.1.4.7 Diethyl 4-(N'-(4-dimethylamino benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydropyridine-3,5-dicarboxylate (4g): Yield 81%, m.p. 217-219 C. FTIR (ATR, cm-
1
1): 3286, 3228, 1663, 1605, 1222. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.15 (s, 1H,
CONH), 8.72 (s, 1H, NH), 7.85 (s, 1H, CH), 7.49-6.70 (m, 8H, ArH), 4.99 (s, 1H, CH), 4.78
(s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.95 (s, 6H, CH3), 2.33 (s, 6H, CH3), 1.13 (t, 6H, CH3,
10

ACCEPTED MANUSCRIPT
J=8.8 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 171.4, 164.5, 158.9, 151.3, 146.7, 137.6,
133.2, 132.7, 127.3, 123.5, 118.9, 116.4, 112.9, 101.9, 68.7, 63.3, 43.8, 42.7, 37.8, 18.1, 16.6.
MS (m/z) 549.2. Anal. Calcd. for C30H36N4O6. C, 65.68; H, 6.61; N, 10.21. Found: C, 65.54;
H, 6.62; N, 10.17.
4.1.4.8 Diethyl 4-(N'-(4-hydroxy-3-ethoxy benzylidine)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (4h): Yield 86%, m.p. 207-209 C. FTIR
1
(ATR, cm-1): 3308, 3226, 1675, 1602, 1212. H NMR (DMSO-d6, 400 MHz, δ in ppm):
11.27 (s, 1H, CONH), 9.37 (s, 1H, OH), 8.72 (s, 1H, NH), 7.85 (s, 1H, CH), 7.23-6.79 (m,
7H, ArH), 5.02 (s, 1H, CH), 4.78 (s, 2H, OCH2), 4.00 (m, 6H, OCH2), 2.32 (s, 6H, CH3), 1.33
(t, 3H, CH3, J=7.2 Hz), 1.12 (t, 6H, CH3, J=9.2 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm):
169.1, 163.8, 158.7, 151.2, 149.2, 138.6, 134.7, 127.3, 124.6, 123.4, 118.5, 117.2, 113.4,
102.4, 69.1, 64.3, 62.8, 43.2, 18.2, 16.5, 14.7. MS (m/z) 566.2. Anal. Calcd. for C30H35N3O8.
C, 63.70; H, 6.24; N, 7.43. Found: C, 63.56; H, 6.21; N, 7.41.
4.1.4.9 Diethyl 4-(N'-(4-methyl benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4i): Yield 90%, m.p. 251-253 C. FTIR (ATR, cm-1):
3291, 3232, 3099, 2997, 1662, 1612, 1219. 1H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.41
(s, 1H, CONH), 8.73 (s, 1H, NH), 7.95 (s, 1H, CH), 7.57-6.72 (m, 8H, ArH), 5.03 (s, 1H,
CH), 4.78 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.32 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.13 (t,
6H, CH3, J=9.4 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 167.5, 163.2, 158.9, 151.8,
142.9, 139.6, 137.6, 132.4, 130.7, 128.9, 122.3, 116.4, 101.9, 69.3, 64.2, 43.7, 18.1, 16.2. MS
(m/z) 520.2. Anal. Calcd. for C29H33N3O6. C, 67.04; H, 6.40; N, 8.09. Found: C, 66.92; H,
6.39; N, 8.02.
4.1.4.10 Diethyl 4-(N'-(4-hydroxy-3-methoxy benzylidine)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (4j): Yield 85%, m.p. 213-215 C. FTIR
1
(ATR, cm-1): 3459, 3318, 3247, 1676, 1612, 1217. H NMR (DMSO-d6, 400 MHz, δ in
ppm): 11.28 (s, 1H, CONH), 9.44 (s, 1H, OH), 8.72 (s, 1H, NH), 7.86 (s, 1H, CH), 7.25-6.71
(m, 7H, ArH), 5.02 (s, 1H, CH), 4.78 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 3.77 (s, 3H, OCH3),
2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3, J=9.4 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm):
171.2, 163.4, 158.5, 152.5, 147.3, 142.7, 136.7, 132.9, 128.7, 123.2, 121.3, 118.5, 116.6,
113.1, 101.9, 68.7, 62.9, 56.7, 43.3, 18.1, 16.5. MS (m/z) 552.3. Anal. Calcd. for
C29H33N3O8. C, 63.15; H, 6.03; N, 7.62. Found: C, 63.03; H, 5.96; N, 7.57.
11

ACCEPTED MANUSCRIPT
4.1.4.11 Diethyl 4-(N'-(1H-indol-3-yl)methylene)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydropyridine-3,5-dicarboxylate (4k): Yield 88%, m.p. 231-233 C. FTIR (ATR, cm-
1
1): 3259, 3201, 3089, 2977, 1675, 1610, 1216. H NMR (DMSO-d6, 400 MHz, δ in ppm):
11.52 (s, 1H, CONH), 11.12 (s, 1H, NH), 8.72 (s, 1H, NH), 8.04 (s, 1H, CH), 7.78-6.82 (m,
9H, ArH), 5.07 (s, 1H, CH), 4.79 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.13
(t, 6H, CH3, J=9.2 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 169.3, 167.5, 159.8, 152.5,
142.3, 138.4, 132.2, 130.5, 128.7, 125.7, 122.1, 120.9, 118.6, 116.5, 114.7, 112.1, 106.4,
102.1, 67.1, 61.8, 42.0, 18.1, 14.3. MS (m/z) 545.6. Anal. Calcd. for C30H32N4O6. C, 66.16;
H, 5.92; N, 10.29. Found: C, 66.02; H, 5.90; N, 10.25.
4.1.4.12 Diethyl 4-(N'-(thiophen-2-yl methylene)-2-phenoxyacetohydrazide)-2,6-dimethyl-
1,4-dihydropyridine-3,5-dicarboxylate (4l): Yield 83%, m.p. 261-263 oC. FTIR (ATR, cm-1):
1
3303, 3218, 3067, 2977, 1671, 1641, 1216. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.14
(s, 1H, CONH), 8.73 (s, 1H, NH), 8.16 (s, 1H, CH), 7.65-6.70 (m, 7H, ArH), 4.95 (s, 1H,
CH), 4.78 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.33 (s, 6H, CH3), 1.12 (t, 6H, CH3, J= 9.4 Hz).
13C NMR (DMSO-d6, 100 MHz, δ ppm): 168.4, 164.5, 158.2, 142.3, 140.3, 138.4, 132.2,
130.7, 128.1, 126.3, 124.5, 123.7, 122.1, 120.9, 117.7, 114.3, 102.3, 67.8, 62.1, 42.3, 18.1,
14.5. MS (m/z) 512.6. Anal. Calcd. for C26H29N3O6S. C, 61.04; H, 5.71; N, 8.21. Found: C,
60.92; H, 5.68; N, 8.22.
4.1.4.13 Diethyl 4-(N'-(pyridin-4-ylmethylene)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4m): Yield 94%, m.p. 216-218 C. FTIR (ATR, cm-1):
1
3301, 3259, 2975, 1665, 1607, 1222. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.76 (s,
1H, CONH), 8.73 (s, 1H, NH), 7.96 (s, 1H, CH), 7.65-6.74 (m, 8H, ArH), 5.07 (s, 1H, CH),
4.79 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.13 (t, 6H, CH3, J=9.4 Hz). 13C
NMR (DMSO-d6, 100 MHz, δ ppm): 167.6, 162.3, 157.8, 147.6, 146.7, 141.3, 140.3, 132.2,
131.3, 125.7, 121.5, 117.7, 114.3, 102.1, 67.8, 62.1, 42.5, 18.1, 14.3. MS (m/z) 507.2. Anal.
Calcd. for C27H30N4O6. C, 64.02; H, 5.97; N, 11.06. Found: C, 63.89; H, 5.98; N, 11.02.
4.1.4.14 Diethyl 4-(N’-((5-methylthiophen-2-yl)methylene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (4n): Yield 88%, m.p. 261-263 C. FTIR
1
(ATR, cm-1): 3291, 3231, 3027, 2975, 1665, 1605, 1219. H NMR (DMSO-d6, 400 MHz, δ
in ppm): 11.34 (s, 1H, CONH), 8.72 (s, 1H, NH), 8.06 (s, 1H, CH), 7.22-6.69 (m, 6H, ArH),
4.91 (s, 1H, CH), 4.78 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.44 (s, 3H, CH3), 2.23 (s, 6H,
CH3), 1.13 (t, 6H, CH3, J=9.2 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 166.8, 163.1,
12

ACCEPTED MANUSCRIPT
158.7, 141.3, 140.3, 138.6, 131.3, 128.6, 125.7, 116.4, 114.2, 102.4, 67.8, 63.1, 41.8, 18.1,
15.2, 14.3. MS (m/z) 526.2. Anal. Calcd. for C27H31N3O6S. C, 61.70; H, 5.94; N, 7.99.
Found: C, 61.55; H, 5.89; N, 7.97.
4.1.4.15 Diethyl (N’- 4-((5-nitrofuran-2-yl)methylene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (4o): Yield 84%, m.p. 231-233 C. FTIR
1
(ATR, cm-1): 3301, 3234, 3065, 2974, 1674, 1611, 1213. H NMR (DMSO-d6, 400 MHz, δ
in ppm): 11.89 (s, 1H, CONH), 8.73 (s, 1H, NH), 7.94 (s, 1H, CH), 7.78-6.72 (m, 6H, ArH),
5.02 (s, 1H, CH), 4.79 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.13 (t, 6H, CH3,
J=9.8 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 173.1, 164.5, 158.5, 154.3, 152.7, 136.7,
135.4, 132.9, 123.2, 121.3, 118.8, 116.4, 101.8, 68.7, 63.1, 43.1, 18.2, 16.5. MS (m/z) 541.2.
Anal. Calcd. for C26H28N4O9. C, 57.77; H, 5.22; N, 10.37. Found: C, 57.62; H, 5.19; N,
10.39.
4.1.4.16 Diethyl (N’-4-((1-hydroxynaphthalen-2-yl)methylene)-2-phenoxyacetohydrazide)-
o
2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (4p): Yield 88%, m.p. 260-262 C.
1
FTIR (ATR, cm-1): 3306, 3263, 3058, 2978, 1664, 1617, 1219. H NMR (DMSO-d6, 400
MHz, δ in ppm): 11.78 (s, 1H, CONH), 9.41 (s, 1H, OH), 8.74 (s, 1H, NH), 8.19 (s, 1H, CH),
7.93-6.88 (m, 10H, ArH), 5.05 (s, 1H, CH), 4.78 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s,
6H, CH3), 1.13 (t, 6H, CH3, J=9.4 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 173.8,
164.8, 161.3, 158.5, 151.8, 143.2, 135.4, 132.7, 131.7, 126.4, 123.6, 121.3, 116.9, 114.7,
102.3, 68.7, 62.9, 42.8, 18.2, 16.6. MS (m/z) 572.1. Anal. Calcd. for C32H33N3O7. C, 67.24;
H, 5.82; N, 7.35. Found: C, 67.10; H, 5.79; N, 7.29.
4.1.4.17 Diethyl 4-(N'-(2,4-dihydroxy benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydropyridine-3,5-dicarboxylate (4q): Yield 81%, m.p. 271-273 C. FTIR (ATR, cm-
1
1): 3380, 3229, 3094, 2973, 1661, 1621, 1223. H NMR (DMSO-d6, 400 MHz, δ in ppm):
11.21 (s, 1H, CONH), 9.92 (s, 1H, OH), 8.71 (s, 1H, NH), 8.38 (s, 1H, OH), 8.15 (s, 1H,
CH), 7.46-6.30 (m, 7H, ArH), 4.95 (s, 1H, CH), 4.78 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23
13
(s, 6H, CH3), 1.12 (t, 6H, CH3, J=9.6 Hz). C NMR (DMSO-d6, 100 MHz, δ ppm): 169.1,
165.4, 161.4, 158.3, 149.2, 133.6, 131.2, 128.2, 124.7, 122.4, 115.7, 113.7, 109.7, 102.0,
66.4, 59.8, 41.2, 18.2, 14.1. MS (m/z) 538.3. Anal. Calcd. for C28H31N3O8. C, 62.56; H, 5.81;
N, 7.82. Found: C, 62.42; H, 5.76; N, 7.79.
4.1.4.18 Diethyl 4-(N'-(4-bromo-2-hydroxybenzylidene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (4r): Yield 89%, m.p. 248-250 C. FTIR
13

ACCEPTED MANUSCRIPT
1
(ATR, cm-1): 3325, 3272, 3013, 2976, 1671, 1612, 1212. H NMR (DMSO-d6, 400 MHz, δ
in ppm): 11.06 (s, 1H, CONH), 10.32 (s, 1H, OH), 8.73 (s, 1H, NH), 8.21 (s, 1H, CH), 7.81-
6.72 (m, 7H, ArH), 5.05 (s, 1H, CH), 4.78 (s, 2H, OCH2), 3.97 (m, 4H, CH2), 2.23 (s, 6H,
CH3), 1.12 (t, 6H, CH3, J=9.2 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 168.3, 164.6,
159.2, 149.5, 142.3, 133.6, 131.2, 125.7, 124.7, 123.2, 119.7, 115.7, 113.7, 109.7, 102.0,
66.4, 59.8, 41.2, 18.2, 14.1. MS (m/z) 599.8. Anal. Calcd. for C28H30BrN3O7. C, 56.01; H,
5.04; N, 7.00. Found: C, 55.86; H, 5.05; N, 6.96.
4.1.4.19 Diethyl 4-(N'-(4-bromo benzylidine)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
dihydropyridine-3,5-dicarboxylate (4s): Yield 90%, m.p. 235-237 C. FTIR (ATR, cm-1):
3307, 3272, 3058, 2957, 1667, 1610, 1228. 1H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.55
(s, 1H, CONH), 8.73 (s, 1H, NH), 7.96 (s, 1H, CH), 7.65-6.73 (m, 8H, ArH), 5.04 (s, 1H,
CH), 4.78 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.23 (s, 6H, CH3), 1.13 (t, 6H, CH3, J=9.2 Hz).
13C NMR (DMSO-d6, 100 MHz, δ ppm): 173.8, 165.2, 158.5, 151.8, 142.9, 135.4, 132.7,
131,2, 126.4, 114.7, 102.3, 68.7, 62.9, 42.8, 18.2, 16.6. MS (m/z) 584.1. Anal. Calcd. for
C28H30BrN3O6. C, 57.54; H, 5.17; N, 7.19. Found: C, 57.46; H, 5.15 N, 7.15.
4.1.4.20
Diethyl
4-(-N'-(1-(4-nitrophenyl)ethylidene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (5a): Yield 91%, m.p. 225-227 C. FTIR
1
(ATR, cm-1): 3309, 3237, 1682, 1667, 1497, 1224. H NMR (DMSO-d6, 400 MHz, δ in
ppm): 11.1 (s, 1H, CONH), 8.77 (s, 1H, NH), 8.24 (d, 2H, ArH, J=12.0 Hz), 8.06 (d, 2H,
ArH, J=12.0 Hz), 7.06-6.78 (m, 4H, ArH), 5.14 (s, 1H, CH), 4.79 (s, 2H, OCH2), 3.98 (m,
4H, CH2), 2.31 (s, 3H, CH3), 2.24 (s, 6H, CH3), 1.13 (t, 6H, CH3, J=10.0 Hz). 13C NMR
(DMSO-d6, 100 MHz, δ ppm): 169.9, 166.9, 163.8, 161.4, 156.3, 147.2, 144.9, 140.6, 134.4,
128.3, 115.2, 113.7, 102.0, 65.0, 58.9, 37.8, 18.2, 14.1. 13.4. MS (m/z) 566.2. Anal. Calcd.
for C29H32N4O8: C, 61.69; H, 5.71; N, 9.92. Found: C, 61.55; H, 5.67; N, 9.88.
4.1.4.21 Diethyl 4-(N'-(1-(thiophen-2-yl)ethylidene)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydropyridine-3,5-dicarboxylate (5b): Yield 83%, m.p. 218-220 C. FTIR (ATR, cm-
1
1): 3294, 3094, 2969, 1689, 1652, 1206. H NMR (DMSO-d6, 400 MHz, δ in ppm): 10.81 (s,
1H, CONH), 8.72 (s, 1H, NH), 7.58-6.70 (m, 7H, ArH), 4.97 (s, 1H, CH), 4.78 (s, 2H,
OCH2), 3.97 (m, 4H, CH2), 2.26 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3, J=7.0 Hz).
13C NMR (DMSO-d6, 100 MHz, δ ppm): 168.2, 164.5, 160.2, 155.8, 136.7, 134.3, 133.2,
128.7, 123.5, 121.7, 117.4, 115.3, 102.1, 64.6, 59.8, 40.2, 18.1, 14.4. 13.3. MS (m/z) 526.3.
Anal. Calcd. for C27H31N3O6S. C, 61.70; H, 5.94; N, 7.99. Found: C, 61.57; H, 5.92; N, 7.93.
14

ACCEPTED MANUSCRIPT
4.1.4.22 Diethyl 4-(N'-(1-(1H-indol-3-yl)ethylidene)-2-phenoxyacetohydrazide)-2,6-dimethyl-
1,4-dihydropyridine-3,5-dicarboxylate (5c): Yield 89%, m.p. 226-228 oC. FTIR (ATR, cm-1):
1
3277, 3210, 3080, 2966, 1684, 1641, 1209. H NMR (DMSO-d6, 400 MHz, δ in ppm): 11.42
(s, 1H, CONH), 10.55 (s, 1H, NH), 8.72 (s, 1H, NH), 8.56-6.76 (m, 9H, ArH), 5.11 (s, 1H,
CH), 4.79 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.27 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.13 (t,
6H, CH3, J=7.2 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 170.4, 167.3, 164.5, 156.5,
138.4, 136.8, 134.2, 128.7, 126.9, 124.1, 120.7, 114.2, 113.5, 102.1, 67.1, 59.3, 42.0, 18.1,
14.3. 13.7. MS (m/z) 559.1. Anal. Calcd. for C31H34N4O6. C, 66.65; H, 6.13; N, 10.03.
Found: C, 66.51; H, 6.12; N, 10.04.
4.1.4.23
Diethyl
4-(N'-(1-(4-bromophenyl)ethylidene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (5d): Yield 90%, m.p. 144-146 C. FTIR
(ATR, cm-1): 3295, 3237, 2976, 1687, 1648, 1202. 1H NMR (DMSO-d6, 400 MHz, δ in
ppm): 10.84 (s, 1H, CONH), 8.72 (s, 1H, NH), 7.86-6.72 (m, 8H, ArH), 5.07 (s, 1H, CH),
4.78 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.25 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.13 (t, 6H,
CH3, J=7.4 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 169.2, 166.7, 162.3, 158.9, 138.5,
136.1, 134.7, 131.4, 128.7, 126.9, 116.3, 114.2, 102.1, 67.1, 59.7, 42.1, 18.1, 14.4. 13.3. MS
(m/z) 598.2. Anal. Calcd. for C29H32BrN3O6. C, 58.20; H, 5.39; N, 7.02. Found: C, 58.03; H,
5.39; N, 6.98.
4.1.4.24 Diethyl 4-(N'-(1-phenylethylidene)-2-phenoxyacetohydrazide)-2,6-dimethyl-1,4-
o
pihydro pyridine-3,5-dicarboxylate (5e): Yield 87%, m.p. 215-217 C. FTIR (ATR, cm-1):
1
3296, 3218, 2976, 1684, 1618, 1208. H NMR (DMSO-d6, 400 MHz, δ in ppm): 10.78 (s,
1H, CONH), 8.72 (s, 1H, NH), 7.79-6.72 (m, 9H, ArH), 5.07 (s, 1H, CH), 4.79 (s, 2H,
OCH2), 3.98 (m, 4H, CH2), 2.25 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3, J=7.4 Hz).
13C NMR (DMSO-d6, 100 MHz, δ ppm): 169.2, 166.4, 159.7, 135.4, 134.7, 132.9, 130.4,
123.5, 121.7, 118.9, 117.6, 116.4, 102.1, 67.4, 59.7, 41.1, 18.1, 14.4. 13.3. MS (m/z) 520.3.
Anal. Calcd. for C29H33N3O6. C, 67.04; H, 6.40; N, 8.09. Found: C, 66.89; H, 6.36; N, 8.05.
4.1.4.25
Diethyl
4-(N'-(1-(4-fluorophenyl)ethylidene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (5f): Yield 91%, m.p. 191-193 C. FTIR
(ATR, cm-1): 3342, 2976, 1693, 1642, 1207. 1H NMR (DMSO-d6, 400 MHz, δ in ppm):
10.79 (s, 1H, CONH), 8.72 (s, 1H, NH), 7.85-6.72 (m, 8H, ArH), 5.07 (s, 1H, CH), 4.78 (s,
2H, OCH2), 3.98 (m, 4H, CH2), 2.24 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.12 (t, 6H, CH3, J=7.8
Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 169.9, 166.8, 156.4, 147.2, 144.9, 140.9,
15

ACCEPTED MANUSCRIPT
134.4, 128.3, 115.2, 113.7, 102.0, 65.3, 62.3, 38.2, 18.2, 14.1. 13.4. MS (m/z) 538.2. Anal.
Calcd. for C29H32FN3O6. C, 64.79; H, 6.00; N, 7.82. Found: C, 64.63; H, 5.95; N, 7.79.
4.1.4.26 Diethyl 4-(N'-(1-(furan-2-yl)ethylidene)-2-phenoxyacetohydrazide)-2,6-dimethyl-
o
1,4-dihydro pyridine-3,5-dicarboxylate (5g): Yield 92%, m.p. 161-163 C. FTIR (ATR, cm-
1
1): 3282, 2956, 1683, 1632, 1217. H NMR (DMSO-d6, 400 MHz, δ in ppm): 10.74 (s, 1H,
CONH), 8.72 (s, 1H, NH), 7.67-6.57 (m, 7H, ArH), 4.99 (s, 1H, CH), 4.78 (s, 2H, OCH2),
3.98 (m, 4H, CH2), 2.27 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.13 (t, 6H, CH3, J=7.4 Hz). 13C
NMR (DMSO-d6, 100 MHz, δ ppm): 168.2, 164.2, 156.4, 154.3, 147.2, 142.7, 141.8, 126.4,
124.8, 123.1, 116.2, 113.7, 102.2, 66.7, 60.4, 37.9, 17.9, 14.2. 13.4. MS (m/z) 510.4. Anal.
Calcd. for C27H31N3O7. C, 63.64; H, 6.13; N, 8.25. Found: C, 63.52; H, 6.15; N, 8.23.
4.1.4.27
Diethyl
4-(N'-(1-(4-chlorophenyl)ethylidene)-2-phenoxyacetohydrazide)-2,6-
o
dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (5h): Yield 91%, m.p. 205-207 C. FTIR
(ATR, cm-1): 3295, 3237, 2976, 1687, 1648, 1202. 1H NMR (DMSO-d6, 400 MHz, δ in
ppm): 10.84 (s, 1H, CONH), 8.72 (s, 1H, NH), 7.86-6.72 (m, 8H, ArH), 5.07 (s, 1H, CH),
4.78 (s, 2H, OCH2), 3.98 (m, 4H, CH2), 2.25 (s, 3H, CH3), 2.23 (s, 6H, CH3), 1.12 (t, 6H,
CH3, J=7.4 Hz). 13C NMR (DMSO-d6, 100 MHz, δ ppm): 169.2, 166.4, 162.3, 160.2, 158.7,
135.1, 134.2, 132.6, 123.4, 121.5, 118.6, 117.3, 116.3, 102.1, 67.4, 59.7, 42.1, 18.1, 14.4.
13.3. MS (m/z) 554.2. Anal. Calcd. for C29H32ClN3O6. C, 62.87; H, 5.82; N, 7.58. Found: C,
62.71; H, 5.80; N, 7.56.
4.2. Pharmacology
4.2.1 Anticonvulsant study
4.2.1.1 Maximal Electroshock Seizure test
Anticonvulsant evaluations were performed by the Anticonvulsant Screening Program
at the Epilepsy Branch of the National Institutes of Neurological Disorders, and Stroke
(NINDS) in Rockville, USA. Groups of six to ten mice (20–40 g each) were used to test the
samples by MES method using phenytoin as a standard drug. An electrical stimulus of 0.2 s
in duration (50 mA at 60 Hz) was delivered via corneal electrodes, which was primed with an
electrolytic solution containing anaesthetic agent. Animals were tested at 0.5 and 4 hour after
i.p. injection of 30, 100 and 300 mg/kg doses. Disappearance of the hindlimb tonic extensor
was used as positive criterion.
16

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4.2.1.2 Subcutoneous pentylene tetrazole (scPTZ) test
Similar to MES method, a group of six to ten mice were taken for scPTZ screening by
using sodium valproate as a standard drug. Animals were pre-treated with various doses of
the test compound. A standard dose of 85 mg/kg of Metrazol (Tetrazole) was injected
subcutoneously. These animals were placed in isolation cages to minimize stress and
observed for the next 30 min to see the absence of a seizure. Failure to observe any seizure in
this duration was defined as protection.
4.2.1.3 Minimal clonic seizure (6 Hz) test
In this method, test compounds (100 mg/kg) were pre-administered to mice via i.p.
injection. At varying times, individual mice (four mice per time point) were challenged with
sufficient current delivered through corneal electrodes to elicit a psychomotor seizure in 97%
of animals (32 mA for 3 sec). Untreated mice would display seizures characterized by a
minimal clonic phase followed by stereotyped, automatistic behaviours described originally
as being similar to the aura of human patients with partial seizures. Animals not displaying
this behaviour were considered as protected.
4.2.1.4 Neurotoxicity study
Rotarod test was performed to detect the motor deficit in mice. Animals were divided
in groups of 4 animals and trained to stay on an accelerating rotarod that rotates at 10
revolutions per minute. The rod diameter was 3.2 cm. Trained animals (able to stay on the
rotarod for at least two consecutive periods of 90 s) were given an i.p injection of the test
compounds at doses of 30, 100 and 300 mg/kg. Neurological deficit was indicated by the
inability of the animal to maintain equilibrium on the rod for at least 1 min in each of the
three trials. The dose at which animal fell off the rod, was determined.
4.2.2. Anti-inflammatory study
Newly synthesized title compounds were screened for their in vivo anti-inflammatory
properties following Carrageenan induced Paw Edema method [43] by using Diclophenac
sodium as standard drug. Male or female Wistar strain rats with a body weight between 100
and 150 g were used. The animals were weighed and divided into different groups (control,
standard and the test groups) of five rats each. The animals were starved overnight. To insure
uniform hydration, the rats received 5 mL of water by stomach tube (controls) or the test drug
(20 mg/kg) dissolved or suspended in the same volume. Thirty minutes later, the rats were
given a subcutaneous injection of 0.05 mL of 1% solution of Carrageenan into the plantar
side of the left hind paw. The paw was marked with ink at the level of the lateral malleolus
and immersed in mercury up to this mark. The paw volume was measured
17

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plethysmographically immediately after injection, after 30, 60, 120 and 180 min. Results
were expressed as mean, by one way ANOVA analysis followed by Dunnet’s-t-test.
4.2.3 Analgesic study
The analgesic study of active target compounds was done by Tail immersion method [44].
The animals were weighed and divided into different groups (control, standard and the test
groups) of five rats each. Young female Wistar rats (170–210 g body weight) were used for
the study. They were placed into individual restraining cages leaving the tail hanging out
freely. The animals were allowed to adapt to the cages for 30 min before testing. The lower 5
cm portion of the tail was marked. This part of the tail was immersed in a cup of freshly filled
water of exactly 55 °C. Within a few seconds the rat reacts by withdrawing the tail. The
reaction time was recorded in 0.5 sec units by a stopwatch. After each determination the tail
was carefully dried. The reaction time was determined before and periodically after either
oral or subcutaneous administration of the test substance, e.g. after 0, 30, 60 and 90 mins. The
cut off time of the immersion was 15 sec. The withdrawal time of untreated animals was
between 1 and 5.5 sec. A withdrawal time of more than 6 sec therefore was regarded as a
positive response.
Acknowledgements
The authors are thankful to National Institute of Technology Karnataka, Mangalore
for financial support and Indian Institute of Science, Bangalore for NMR spectral facilities,
SAIF Punjab and SAIF Shillong for mass spectral facilities.
References:
[1]
[2]
[3]
[4]
A. Karakurt, M. Ozalp, S. Isik, J.P. Stables, S. Dalkara, Synthesis, anticonvulsant and
antimicrobial activities of some new 2-acetylnapgthalene derivatives, Bioorg. Med.
Chem. 18 (2010) 2902-2911.
M.C. Picot, M. Baldy-Moulinier, J.P. Daurs, P. Dujols, A. Crespel, The prevalence of
epilepsy and pharmacoresistant epilepsy in adults: A population based study in a
western European country, Epilepsia 49 (2008) 1230–1238.
M. Naithani, S. Chopra, B.L. Somani, R.K. Singh, Studies on adverse metabolic
effects of antiepileptics and their correlation with blood components, Current
Neurobiology, 01 (2010) 117-120.
R. Kulandasamy, A.V. Adhikari, J.P. Stables, Synthesis and anticonvulsant activity
of some new bishydrazones derived from 3,4-dipropyloxythiophene, Eur. J. Med.
Chem. 44 (2009) 3672-3679.
18

ACCEPTED MANUSCRIPT
[5]
B. Malawska, K. Kulig, A. Spiewak, J.P. Stables, Investigation into new
anticonvulsant derivatives of α-substituted N-benzylamides of -hydroxy and
-
acetoxybutyric acid. Part 5: Search for new anticonvulsant compounds, Bioorg. Med.
Chem. 12 (2004) 625-632.
[6]
[7]
P. Bellemann, Innovative approaches in drug research. Elseveir: Amsterdam. 1984,
23-26.
A. Shafiee, N. Rastkari, M. Sharifzadeh, Anticonvulsant activities of new 1,4-
dihydropyridine derivatives containing 4-nitroimidazolyl substituents, DARU, 12
(2004) 81-86.
[8]
[9]
L.K.C. Desmedt, C.J.E. Niemegeers, P.A.J. Janssen, Anticonvulsive properties of
cinnarizine and flunarizine in rats and mice, Arzneim. Forsch. 25 (1975) 1408-1415.
S.R. Pattan, N.S. Dighe, D.S. Musmade, S.K. Tambe, S.H. Kale, V.M. Gaware, P.A.
Chavan, Synthesis and evaluation of some new substituted 1,4-dihydropyridine
derivatives and their anticonvulsant activity, J. Chem. Pharm. Res. 02 (2010) 246-
252.
[10]
[11]
G. Prashanthi, K.V.S.R.G. Prasad, K. Bharathi, Design, synthesis and evaluation of
dialkyl 4-(benzo[d][1,3]dioxol-6-yl)-1,4-dihydro-2,6-dimethyl-1-substituted pyridine-
3,5-dicarboxylates as potential anticonvulsants and their molecular properties
prediction, Eur. J. Med. Hem. 66 (2013) 516-525.
Y.S. Sadanandam, M.M. Shetty, K.R.M. Reddy, P. Leelavathi, Synthesis and
pharmacology of new 1,4-dihydropyridines. 2,6-Dimethyl-4-(substituted phenyl) or
(2-furyl)-, (2-thienyl)- or (3-pyridyl)-3,5di[(N-methyl) or (N-diethyl)]carbamoyl-1,4-
dihydropyridines as potent calcium-channel blockers, Eur. J. Med. Chem. 29 (1994)
975-979.
[12]
[13]
B. Mishra, R. Mishra, Synthesis of some new 1,4-dihydropyridine derivatives for anti-
inflammatory activity, The Pharmacist, 02 (2007) 13-16.
H. Komoda, T. Inoue, K. Node, Anti-inflammatory properties of Azelnidipine, a
dihydropyridine based calcium channel blockers, Clin. Exp. Hypertens. 32 (2010)
121-128.
[14]
[15]
N.A. Ismail, A.A. Shaheen, M.M. El-Sawalhi, Y.M. Megahed, Effect of calcium
channel antagonists in modifying the inhibitory influence of adenosine on insulin
secretion, Arzneim.- Forsch Drug Res. 45 (1995) 865-868.
M.A. Beaven, V. Ramkumar, H. Ali, Adenosine-A3 receptors in mast-cells, Trends
Pharmacol. Sci. 15 (1994) 13-14.
19

ACCEPTED MANUSCRIPT
[16]
S. Ulloora, S. Kumar, R. Shabaraya, A.V. Adhikari, New dihydropyridine derivatives:
Anti-inflammatory, analgesic and docking studies, Med. Chem. Res. 22 (2013) 1549-
1562.
[17]
[18]
S. Rollas, S.G. Kucukguzel, Biological activities of hydrazone derivatives, Molecules
12 (2007) 1910-1939.
J.V. Ragavendran, D. Sriram, S.K. Patel, I.V. Reddy, N. Bharathwajan, J. P. Stables,
P. Yogeeswari, Design and synthesis of anticonvulsants from combined phthalimide-
GABA-anilide and hydrazone pharmacophore, Eur. J. Med. Chem. 42 (2007) 146-
151.
[19]
[20]
[21]
M. Gokce, S. Utku, E. Kupeli, Synthesis, analgesic and anti-inflammatory activities of
6-substituted-3(2H)-pyridazinone-2-acetyl-2-(p-substituted/nonsubstituted
hydrazone derivatives, Eur. J. Med. Chem. 44 (2009) 3760-3764.
benzal)
C.M. Moldovan, O. Oniga, A. Parvu, B. Tiperciuc, P. Verite, A. Pirnau, O. Crisan, M.
Bojita, R. Pop, Synthesis and anti-inflammatory evaluation of some new
acylhydrazones bearing 2-aryl thiazole, Eur. J. Med. Chem. 46 (2011) 526-534.
P. Hernandez, M. Cabrera, M. L. Lavaggi, L. Celano, I. Tiscornia, T.R.D. Costa, L.
Thomson, M.B. Fogolin, A.L.P. Miranda, L. M. Lima, E.J. Barreiro, M. Gonzalez, H.
Cerecetto, Discovery of new orally active analgesic and anti-inflammatory hybrid
furoxanyl N-acyl hydrazone derivatives, Bioorg. Med. Chem. 20 (2012) 2158-2171.
S. Carradori, D. Secci, A. Bolasco, D. Rivanera, E. Mari, A. Zicari, L.V. Lotti, B.
Bizzarri, Synthesis and cytotoxicity of novel (thiazol-2yl)hydrazine derivatives as
promising anti-candida agents, Eur. J. Med. Chem. 65 (2013) 102-111.
[22]
[23]
[24]
[25]
[26]
E. Vavrikova, S. Polanc, M. Kocevar, K. Horvati, S. Bosze, J. Stolarikova, K.
Vavrova, J. Vinsova, New fluorine-containing hydrazones active against MDR-
tuberculosis, Eur. J. Med. Chem. 46 (2011) 4937-4945.
E. Vavrikova, S. Polanc, M. Kocevar, J. Kosmrlj, K. Horvati, S. Bosze, J. Stolarikova,
A. Imramovsky, J. Vinsova, New series of isoniazid hydrazones linked with electron-
withdrawing substituents, Eur. J. Med. Chem. 46 (2011) 5902-5909.
A.M. Pieczonka, A. Strzelczyk, B. Sadowska, G, Mloston, P. Staczek, Synthesis and
evaluation of antimicrobial activity of hydrazones derived from 3-oxido-1H-
imidazole-4-carbohydrazides, Eur. J. Med. Chem. 64 (2013) 389-395.
J. Lou, Z. Liu, Y. Li, M. Zhou, Z. Zhang, S. Zheng, R. Wang, J. Li, Synthesis and
antitumor activities of N1-benzylidine-2-(4-oxothieno[2,3-d]pyrimidin-3(4H)-yl)
acetohydrazone derivatives, Bioorg. Med. Chem. Lett. 21 (2011) 6662-6666.
20

ACCEPTED MANUSCRIPT
[27]
[28]
[29]
[30]
[31]
A.T. Mavrova, D. Wesselinova, N. Vassilev, J.A. Tsenov, Design, synthesis and anti-
proliferative properties of some new 5-substituted-2-iminobenzimidazole derivatives,
Eur. J. Med. Chem. 63 (2013) 696-701.
S.M. Siddiqui, A. Salahuddin, A. Azam, Synthesis, characterization and anti-amoebic
activity of some hydrazone and azole derivatives bearing pyridyl moiety as a
promising heterocyclic scaffold, Eur. J. Med. Chem. 49 (2012) 411-416.
A.R. Todeschini, A.L.P. Miranda, K.C. Silva, S.C. Parrini, E.J. Barreiro, Synthesis
and evaluation of analgesic , anti-inflammatory and antiplatelet properties of new 2-
pyridylarylhydrazone derivatives, Eur. J. Med. Chem. 33 (1998) 189-199.
A.R. Todeschini, A.L.P. Miranda, K.C. Silva, S.C. Parrini, E.J. Barreiro, Synthesis
and evaluation of analgesic, anti-inflammatory and antiplatelet properties of new 2-
pyridylarylhydrazone derivatives, Eur. J. Med. Chem. 33 (1998) 189-199.
J.R. Dimmock, S.C. Vashishtha, J.P. Stables, Anticonvulsant properties of various
acetylhydrazones, oxamoylhydrazones, and semicarbazones derived from aromatic
and unsaturated carbonyl compounds, Eur. J. Med. Chem. 35 (2000) 241-248.
D.J. Triggle, 1,4-Dihydropyridines as calcium channel ligands and privileged
structures, Cell. Mol. Neurobiol. 23 (2003) 293-303.
[32]
[33]
N. Pedemonte, D. Boido, O. Moran, M. Giampieri, M. Mazzei, R. Ravazzolo, L.J.V.
Galietta, Structure-Activity Relationship of 1,4- dihydropyridines as potentiators of
the cystic fibrosis transmembrane conductance regulator chloride channel, Mol.
Pharmacol. Fast Forward, 72 (2007) 197-207.
[34]
H.S. White, J.H. Woodhead, M.R. Franklin, General principles: Experimental
selection, quantification and evaluation of antiepileptic drugs, in: R.H. Levy, R.H.
Mattson, B.S. Meldrum (Eds.), Antiepileptic Drugs, 4th ed., Raven Press, New York,
1995, pp. 99–110.
[35]
[36]
[37]
E.A. Swinyard, L.D. Clark, J.T. Miyahara, H.H. Wolf, Studies on the mechanism of
amphetamine toxicity in aggregated mice, J. Physiol. 132 (1961) 97–102.
N.W. Dunham, T.S. Miya, A note on simple apparatus for detecting neurological
deficit in rats and mice, J. Am. Pharm. Assoc. Sci. Ed. 46 (1957) 208-209.
M.E. Barton, B.D. Klein, H.H. Wolf, H.S. White, Pharmacological characterization of
the 6 Hz psychomotor seizure model of partial epilepsy, Epilepsy Res. 47 (2001) 217-
227.
21

ACCEPTED MANUSCRIPT
[38]
[39]
M. Dawidowski, F. Herold, A. Chodkowski, J. Kleps, Synthesis and anticonvulsant
activity of novel 2,6-diketopiperazine derivatives. Part 2: Perhydropyrido[1,2-
a]pyrazines, Eur. J. Med. Chem. 48 (2012) 347-353.
Y. Xia, C.D. Fan, B.X. Zhao, J. Zhao, D.S. Shin, J.Y. Miao, Synthesis and structure-
activity relasionships of novel 1-arylmethyl-3-aryl-1H-pyrazole-5-carbohydrazide
hydrazone derivatives as potential agents against A549 lung cancer cells, Eur. J. Med.
Chem. 43 (2008) 2347-2353.
[40]
[41]
J.E. Lightowler, H.J. Rylance, On the anti-inflammatory activity of some substituted
phenolic compounds, Brit. J. Pharmacol. 22 (1964) 221-227.
R. Kulandasamy, A.V. Adhikari, J.P. Stables, A new class of anticonvulsants
possessing 6 Hz activity: 3,4 dialkoxy thiophene bishydrazones, Eur. J. Med. Chem.
44 (2009) 4376-4384.
[42]
R.A. Rane, V.N. Telvekar, Synthesis and evaluation of novel chloropyrolle molecules
designed by molecular hybridisation of common pharmacophores as potential
antimicrobial agents, Bioorg. Med. Chem. Lett. 20 (2010) 5681-5685.
K. Yoshimasa, H. Hiroshi, T. Susumu, W. Masako, O. Kasuo, Anti-inflammatory
actions of ephedrinses in acute inflammations, Planta Med. 51 (1985) 325-331.
L.C.D. Stasi, M. Costa, S.L.J. Mendacolli, M. Kirizawa, C. Gomes, G. Trolin,
Screening in mice of some medicinal plants used for analgesic purposes in the state of
SaO Paulo, J. Ethnopharmacol. 24 (1988) 205-211.
[43]
[44]
22

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Figure captions
Table 1: Anticonvulsant and toxicity screening results of active compounds
Table 2: Anticonvulsant activity of selected samples in 6 Hz screening method
Table 3: Anti-inflammatory activity data of compounds 4a-s and 5a-h
Table 4: Analgesic activity data of selected hydrazones
Figure 1: Design of new dihydropyridine derivatives
Scheme 1: Synthesis of intermediates and final compounds 4a-s and 5a-h
23

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Table 1: Anticonvulsant screening results of active compounds.
Sample
R
MESa
0.5 h 4.0 h
4e
4-Hydroxyphenyl
-
100
300
100
300
100
300
100
300
30
4i
p-Tolyl
-
4j
4k
Vanilinyl
-
3-Indolyl
-
4p
1-Hydroxy-naphthalein-2-yl
-
5c
Indole-3-yl
-
5f
4-Fluorophenyl
-
5h
4-Chlorophenyl
-
Phenytoin
Sodium
valproate
-
-
30
x
x
aDoses of 30, 100, 300 mg/kg of the compounds were administered and the protection was
measured after 0.5 and 4.0 hours. The figures indicate the minimal concentration of sample
required to cause protection in at least 50% of animals. The dash (-) indicates the absence of
activity, while (x) denotes not tested.

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Table 2: Anticonvulsant activity of selected samples in 6 Hz screening method.a
Compound
Time (hours)
name
4e
0.25
0/4
0/4
1/4
0/4
0/4
0.5
1/4
1/4
0/4
0/4
0/4
1.0
0/4
1/4
2/4
0/4
2/4
2.0
0/4
0/4
0/4
0/4
0/4
4.0
0/4
0/4
0/4
0/4
0/4
4j
4p
5c
5f
aA dose of 100 mg/kg was used. Anticonvulsant screening was done after 0.25, 0.5, 1.0, 2.0 and 4.0 hour against
4 mice each. The data (a/b) indicates the number of animals displayed activity against number of tested animals.

ACCEPTED MANUSCRIPT
Table 3: Anti-inflammatory activity data of compounds 4a-s and 5a-h
Percentage Inhibition
Compounds
1/2h
16.67
12.88
10.61
11.36
8.333
18.18
31.82
15.91
13.64
9.091
34.09
43.18
43.18
16.67
37.12
43.94
43.94
51.52
50
1 h
2 h
3 h
Diclophenac
41.03
42.31
39.74
15.38
16.03
39.1
61.11
52.78
57.22
29.44
8.889
53.89
57.22
47.78
46.11
44.44
57.22
58.89
61.67
46.67
57.22
62.22
62.22
68.89
65.56
67.78
47.78
59.44
64.44
58.89
57.78
61.67
62.78
58.89
65.26
53.29
56.28
49.10
31.13
55.09
58.08
53.89
48.50
44.91
59.28
60.47
61.07
47.30
56.28
61.07
61.07
66.46
64.67
66.46
52.69
57.48
65.86
56.29
56.88
61.078
67.06
56.88
4a
4b
4c
4d
4e
4f
46.79
26.28
32.69
29.49
42.31
49.36
51.28
35.9
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
48.08
55.13
53.21
60.9
58.97
58.33
33.33
49.36
54.49
45.51
42.95
54.49
48.08
46.79
4s
5a
5b
5c
5d
5e
5f
50
13.64
42.42
47.73
37.12
34.85
42.42
39.39
38.64
5g
5h

ACCEPTED MANUSCRIPT
Table 4: Analgesic activity data of selected hydrazones
Tail flick latency in secs
Compound
0 min
30 min
60 min
90 min
Control
3.35±0.028
3.23±0.017
3.17±0.017
3.25±0.028
3.25±0.005
3.23±0.033
3.24±0.003
3.23±0.005
6.25±0.02
4.56±0.008
4.92±0.005
4.99±0.101
5.41±0.005
5.15±0.028
3.34±0.005
6.95±0.02
5.73±0.020
6.1±0.057
6.11±0.063
6.30±0.018
5.91±0.023
3.25±0.005
7.45±0.02
6.8±0.017
6.9±0.028
6.92±0.014
7.23±0.020
7.12±0.012
Standard
4e
4f
4k
4q
5c

ACCEPTED MANUSCRIPT
O
O
NH
R
N
Electron pair donors
Hydrophobic unit
EtO2C
CO2Et
N
H