Design and synthesis of niflumic acid-based N-acylhydrazone derivatives as novel anti-inflammatory and analgesic agents

Article abstract of DOI:10.1007/s00044-012-0235-3

A new series of niflumic acid-based N-acylhydrazone derivatives 5a-p were synthesized and evaluated for their anti-inflammatory and analgesic activities. Most of the compounds have shown anti-inflammatory activity with a moderate-to-excellent activity range (20-80 % reduction in inflammation). Among them, 3-chlorophenyl 5d and 3-pyridyl derivatives 5o exhibited the most potent anti-inflammatory activity relative to niflumic acid as the reference drug (77, 76, and 70 % reduction in inflammation at 1-h postdrug administration, respectively). Also, molecular simplification of niflumic acid through replacing the N-aryl group with N-methyl group produced compounds 6a-f with anti-inflammatory activity in a quite similar manner to those of their parent derivatives. In this subgroup, 4-pyridyl derivative 6f showed the most potent anti-inflammatory activity relative to niflumic acid (80 % reduction in inflammation at 1-h postdrug administration). The compounds with highest anti-inflammatory activity were subjected to analgesic assays and showed moderate-to-excellent analgesic activities. The compound 5j, 4-methoxy derivative, exhibited the highest analgesic activity relative to niflumic acid (97 and 68 % activity, respectively).

Full text of DOI:10.1007/s00044-012-0235-3

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2013) 22:2411–2420
DOI 10.1007/s00044-012-0235-3
ORIGINAL RESEARCH
Design and synthesis of niflumic acid-based N-acylhydrazone
derivatives as novel anti-inflammatory and analgesic agents
•
Amin Kheradmand Latifeh Navidpour
•
•
•
Hamed Shafaroodi Ghazaleh Saeedi-Motahar
Abbas Shafiee
Received: 20 February 2012 / Accepted: 13 September 2012 / Published online: 27 September 2012
Ó Springer Science+Business Media New York 2012
Abstract A new series of niflumic acid-based N-acylhyd-
razone derivatives 5a–p were synthesized and evaluated for
their anti-inflammatory and analgesic activities. Most of the
compounds have shown anti-inflammatory activity with a
moderate-to-excellent activity range (20–80 % reduction in
inflammation). Among them, 3-chlorophenyl 5d and 3-pyri-
dyl derivatives 5o exhibited the most potent anti-inflamma-
tory activity relative to niflumic acid as the reference drug (77,
76, and 70 % reduction in inflammation at 1-h postdrug
administration, respectively). Also, molecular simplification
of niflumic acid through replacing the N-aryl group with N-
methyl group produced compounds 6a–f with anti-inflam-
matory activity in a quite similar manner to those of their
parent derivatives. In this subgroup, 4-pyridyl derivative 6f
showed the most potent anti-inflammatory activity relative to
niflumic acid (80 % reduction in inflammationat1-h postdrug
administration). The compounds with highest anti-inflam-
matory activity were subjected to analgesic assays and
showed moderate-to-excellent analgesic activities. The com-
pound 5j, 4-methoxy derivative, exhibited the highest anal-
gesic activity relative to niflumic acid (97 and 68 % activity,
respectively).
Keywords Niflumic acid hydrazide Á Anti-inflammatory Á
Analgesic
Introduction
The non-steroidal anti-inflammatory drugs (NSAIDs), which
are also effective as analgesics, being widely prescribed
medicines for treatment of pain, pyrexia, inflammation, and
arthritis (Botting, 1999; Vane, 1971). These drugs block
biosynthesis of prostaglandins (PGs) which are the important
lipid mediators of inflammation as well as numerous
homeostatic physiological functions by inhibiting enzyme
PG H2 endoperoxide synthase or cyclooxygenase (COX)
enzymes. It is now well recognized; COX enzymes exist in
two major isoforms, COX-1 and COX-2, which are respon-
sible for cytoprotective effects and for inflammatory effects,
respectively. COX-1 is known as a constitutive form of COX
and expressed in all tissues, while COX-2 is an inducible
form and expressed only in kidney, brain, and ovaries by pro-
inflammatory molecules such as Interleukin-1 (IL-1), tumor
necrosis factor-a (TNF-a), lipopolysaccharide (LPS), and
tissue plasminogen activator (TPA) (Botting, 1999; Hawkey,
2000; Guslandi, 1997; Ziakas et al., 2005). It is found that
housekeeping PGs produced by COX-1 are critical to the
maintenance of normal renal function, gastric mucosal
integrity, vascular hemostasis, and the autocrine response to
circulating hormones. Classical NSAIDs may cause severe
gastrointestinal (GI) toxicity such as bleeding, perforation,
ulceration, and also cardiorenal complications due to indis-
criminate inhibition of both COX isoforms which greatly
limit their therapeutic usefulness (Yang et al., 2009; Girgis
et al., 2007). Therefore, synthetic approaches based upon
chemical modification of NSAIDs have been taken with the
aim of improving their safety profile.
A. Kheradmand Á L. Navidpour (&) Á A. Shafiee (&)
Department of Medicinal Chemistry, Faculty of Pharmacy and
Drug Design & Development Research Center, Tehran
University of Medical Sciences, 14176 Tehran, Iran
e-mail: navidpur@sina.tums.ac.ir
A. Shafiee
e-mail: ashafiee@ams.ac.ir
H. Shafaroodi Á G. Saeedi-Motahar
Pharmacology and Toxicology Department, Pharmaceutical
Sciences Branch and Pharmaceutical Sciences Research Center,
Islamic Azad University, Tehran, Iran
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Med Chem Res (2013) 22:2411–2420
O
of the carboxylic function with N-acylarylhydrazone having
less acidic amide hydrogen has been taken with the aim of
improving the safety profile.
OH
O
N
Ar
O
O
N
NH
N
H
Considering the above results and as a part of our
ongoing program to design new anti-inflammatory agents
(Almasirad et al., 2006; Moradi et al., 2010), herein, we
describe the design, synthesis, and the biological evalua-
tion of a novel diverse group of N-acylarylhydrazone
derivatives of niflumic acid (5) and their simplified forms
N-methyl analogs (6) with different substituents on the
terminal phenyl (or pyridyl) ring.
R
R'
CF3
R'= H and Ar= 2-thiophene (LASSBio-294)
R'=NO2 and Ar=3,5-di-tert-butyl-4-hydroxyphenol
(LASSBio-881)
R=H, Niflumic acid
R=CH3, Flunixin
Fig. 1 Representative examples of pyridine derivatives of fenamates
and N-acylarylhydrazones
The most usual available method for the synthesis of
substituted hydrazone in the literature is the acid catalyzed
reaction of suitable hydrazine derivative with substituted
aliphatic or aromatic aldehyde (Bezerra-Netto et al., 2006;
Figueiredo et al., 2000; Duarte et al., 2007).
Pyridine derivatives form an important class of hetero-
cyclic compounds and have attracted the attention of many
scientists (Sondhi et al., 2002; Effland and Klein, 1991).
The pyridine nucleus is present in niflumic acid 1 and
flunixin 2, two traditional NSAIDs belonging to the class of
fenamates (Fig. 1). Interestingly, the fenamates appears
also to compete with PGs for binding at the PG receptor
site in which this activity potentially antagonizes the
physiopathological effects of PGs that have already been
formed. However, fenamates are still endowed with most
of the adverse effects induced by NSAIDs, particularly GI
bleeding, ulceration, and perforation (Cocco et al., 2004).
Moreover, local irritation by the direct contact of the
carboxylic acid (–COOH) moiety of NSAIDs with GI
mucosal cells (topical effect) and decreased tissue PG
production in tissues which undermine the physiological
role of cytoprotective PGs in maintaining GI health and
homeostasis (Smith et al., 1998; Hawkey et al., 2000) are
two main factors that NSAIDs cause GI damage.
Results and discussion
Chemistry
The synthetic reactions leading to the substituted arylidene-
2-[(3-trifluoromethylanilino) or methylamino]nicotinic
acid hydrazides (5 and 6) were outlined in Scheme 1.
2-Aryl (or alkyl) nicotinic acid hydrazides (4a–b) are key
intermediates for the production of the title compounds
5a–p and 6a–f. The starting materials, 2-(3-trifluorome-
thylanilino)nicotinic acid (1a) was prepared by the reaction
of 2-chloronicotinic acid 2 with 3-(trifluoromethyl)aniline
in the presence of catalytic amount of potassium iodide
(Hoffmann and Faure, 1968). Similarly, methylamino-
dechlorination of compound 2 with aqueous solution of
methylamine hydrochloride led to the formation of
2-(methylamino)nicotinic acid 1b. Subsequently, acid-cat-
alyzed esterification of latter compounds (1a–b) in ethanol
Some evidences suggest that the hydrazone moiety pos-
sesses a pharmacophoric character for the inhibition of COX
in N-acylhydrazones (NAH) (Lima et al., 2000), due to their
ability to mimic the bis-allylic moiety of unsaturated fatty
acids, for example, arachidonic acid (AA), precursor of the
eicosanoid biosynthesis (Fig. 1). Therefore, the derivatization
Scheme 1 Synthesis of
niflumic acid-based NAH
derivatives (5 and 6). Reagents
and conditions:
(a) CH3NH2ÁHCl or 3-CF3-
aniline, KI, 140 °C then 100 °C,
1.5 h; (b) EtOH, H?; reflux,
16–18 h; (c) NH2NH2ÁH2O,
EtOH, r.t. 24 h; (d) substituted
aryl aldehydes, EtOH, HCl, r.t.
5–24 h
O
O
O
Et
OH
O
b
OH
N
NH
R
N
NH
R
N
Cl
2
1a: R= 3-CF3-Ph
1b: R= CH3
3a: R= 3-CF3-Ph
3b: R= CH3
c
O
O
NH2
d
N
Ar
N
H
N
H
N
NH
N
NH
R
R
4a: R= 3-CF3-Ph
4b: R= CH3
5a-p: R= 3-CF3-Ph
6a-f: R= CH3
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Med Chem Res (2013) 22:2411–2420
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Table 1 2-Aryl (or alkyl)aminopyridine hydrazone derivatives 5 and 6
O
O
N
Ar
N
N
Ar
H
N
H
N
NH
N
NH
CH3
CF3
5
6
Compound
Ar
AI acticity (%)a
at 30 min
at 1 h
at 2 h
at 3 h
at 4 h
5a
C6H5
60.35 10.93
58.25 4.12
33.87 15.61
77.82 2.18
52.38 6.15
67.52 9.03
59.25 6.90
51.40 5.82
52.82 3.15
50.40 6.87
37.81 8.18
60.06 4.91
55.89 6.34
61.26 5.75
59.08 3.77
68.09 3.35
56.46 6.01
67.13 4.74
46.46 10.38
56.12 10.36
66.32 6.39
63.20 5.99
64.12 6.88
53.91 7.47
51.51 6.35
43.23 13.96
76.70 3.75
67.22 3.48
63.80 7.74
70.52 7.92
50.80 5.22
58.75 1.68
59.42 8.38
55.69 9.33
70.02 4.27
54.36 7.76
63.47 4.27
76.14 4.13
70.16 4.83
67.57 5.18
68.62 7.81
54.72 9.42
64.63 8.60
61.14 6.39
80.38 1.91
70.41 4.92
36.75 12.75
52.76 6.07
41.16 14.68
63.48 4.71
52.75 9.87
65.43 8.31
68.01 5.94
46.86 6.12
49.69 4.17
42.40 3.56
44.68 9.33
49.04 7.84
40.58 10.15
51.37 3.24
62.36 3.62
65.17 8.03
47.19 5.05
61.72 2.56
54.13 7.82
51.46 7.26
43.72 7.73
60.44 7.43
70.08 10.06
21.19 10.67
36.98 3.90
41.33 14.73
55.21 5.97
48.54 9.47
48.99 8.82
59.52 9.95
38.24 11.27
30.26 6.74
26.46 7.43
24.11 1.72
44.01 7.97
28.52 9.94
39.49 4.71
52.41 4.07
54.93 4.48
22.66 5.95
39.55 5.66
22.44 7.64
49.50 11.88
27.69 5.23
55.02 8.0
30.98 13.80
29.75 6.44
36.53 14.91
40.37 8.78
43.71 7.13
35.84 7.24
61.61 6.91
21.07 9.78
14.90 6.65
13.96 5.43
19.80 6.54
52.91 7.55
28.62 8.87
28.19 3.03
36.03 8.77
45.92 5.26
14.78 6.11
40.35 4.27
18.19 4.27
42.25 10.87
13.77 5.22
15.46 22.29
52.01 7.12
5b
3-FC6H4
5c
4-FC6H4
5d
3-ClC6H4
5e
4-ClC6H4
5f
3-OHC6H4
4-OHC6H4
3,4-(OH)2C6H3
3-OMeC6H4
4-OMeC6H4
2,4-(OMe)2C6H3
3,4-(OMe)2C6H3
3,4,5-(OMe)3C6H2
4-Me2NC6H4
3-Pyridyl
5g
5h
5i
5j
5k
5l
5m
5n
5o
5p
4-Pyridyl
6a
C6H5
6b
3-ClC6H4
6c
4-ClC6H4
6d
3-OMeC6H4
3-Pyridyl
6e
6f
4-Pyridyl
Niflumic acid
70.58 5.17
a
Inhibitory activity on carrageenan-induced rat paw edema. The results are expressed as mean SEM (n = 4–6) following a 10 mg/kg i.p.
dose of the test compound
afforded corresponding ethyl esters 3 which on treatment
with hydrazine hydrate gave related nicotinic acid hydra-
zides (4a–b) (Kamal et al., 2007).
According to the literature, the hydrazone may exist as
Z/E geometrical isomers about the C=N double bond or cis/
trans amide conformers (Bezerra-Netto et al., 2006; Duarte
et al., 2007; Figueiredo et al., 2000; Ribeiro et al., 1998).
To investigate the possible influence of the conforma-
tional restriction in the pharmacophoric NAH side chain,
promoted by a possible intramolecular H-bond formation,
molecular modeling studies using AM1 Hamiltonian were
carried out in MOE 2008.10 program using the compounds
5a and 6a (Fig. 2). This study indicated that the compound
bearing s-trans like conformation (conformation B, with
88 kcal/mol for 5a and 70 kcal/mol for 6a) has lower
energy than the isomeric s-cis like conformation (confor-
mation A, with 93–95 kcal/mol for 5a and 76 kcal/mol for
6a) (Fig. 2). In isomeric s-trans like conformation, the
Finally, with the hydrazide intermediate 4 in hands, the
new NAH target compounds (5a–p and 6a–f) were obtained
in good to excellent yields, by condensing the hydrazide
intermediate with the appropriate aldehydes in ethanol,
using hydrochloric acid as catalyst (Table 1).
The next step of this work was to determine the relative
configuration of the imine double bond of arylidenenicotinic
acid derivatives 5, 6, to assure the diastereomeric ratio
essential to the complete understanding of the biological
effect. The careful analysis of the 1H-NMR of 5 and 6 allowed
us to detect the presence of one singlet signal related to the
imine hydrogen at 8.2–8.55 ppm.
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Med Chem Res (2013) 22:2411–2420
Therefore, conformation E was the most stable for 5a and 6a
(Fig. 2).
s-cis like conformation
N
O
O
HN
H
NH
N
N
NH
R
Anti-inflammatory activity
N
NH
s-trans like conformation
H
R
In vivo pharmacological evaluation of 5a–p and 6a–f was
carried out to assess their potential anti-inflammatory
activity. Qualitative structure–activity relationship data
acquired using the carrageenan-induced rat paw edema
assay (Al-Haboubi and Zeitlin, 1983), showed that these
group of compounds exhibit anti-inflammatory activity
with a moderate-to-excellent activity range (20–77 % inhi-
bition) in comparison with niflumic acid as the reference
drug (52–70 % reduction in inflammation) at 30 min to 4 h
(Table 1).
5a, 6a-B
5a, 6a-A
H
N
N
HN
HN
H
O
O
N
NH
R
N
NH
R
First, the substituents on the terminal phenyl moiety
attached to the imine functional group of niflumic acid
hydrazide derivatives 5 were rationally selected to acquire
information about the influence of electronic and physico-
chemical parameters on pharmacological activity.
The analysis of the results revealed that introduction of
small lipophilic chloro substituent (5d, e) or hydrophilic
hydroxyl moiety (5f, g) produced compounds with improved
anti-inflammatory activities (67–77 % reduction in inflam-
mation at 1-h postdrug administration), while dimethyl-
amino (5n) or methoxy (5i, j) substituted compounds were
shown similar activities (58–63 % reduction in inflamma-
tion) for an i.p. dose of 10 mg/kg. Polysubstitution in most
cases resulted in compounds with less activity.
5a, 6a-D
5a, 6a-C
H
H
N
N
HN
HN
O
O
N
NH
R
N
NH
R
5a, 6a-E (s-trans-E)
5a, 6a-F (s-trans-Z)
Then, the effect of changing the position of substituents
on the phenyl ring was investigated. In general, most of the
meta substituted compounds (except for fluoro derivatives
5b, c) were preferred over para substituted ones.
Substitution of phenyl moiety with pyridyl produced
compounds with noticeably improved anti-inflammatory
activity (70–76 % reduction in inflammation at 1-h post-
drug administration).
5a: R= CF3-Ph
6a: R= CH3
Fig. 2 Different possible conformations for 5a and 6a
possible intramolecular H-bond was formed between oxy-
gen in C=O and NH of anilino substituent while in isomeric
s-cis like conformation the hydrogen bonds was formed
between N of anilino and NH of amidic group. Even
though in both conformations A and B hydrogen bond
formation is possible, but s-trans seems to be more stable.
Then, the systematic conformational analysis was carried
out to determine which one of the conformers C or D (while
the relative conformation of carbonyl and imino groups are
different) is more stable. For derivative 5a, the obtained value
for the conformation C was 88 kcal/mol and for 6a was
70 kcal/mol, whiletheenergyfoundfortheconformationD of
5a was 92 kcal/mol and for 6a was 75 kcal/mol (Fig. 2).
Moreover, regarding the stereochemistry of hydrazone moi-
ety, the (E)-diastereomer (5a: 90 kcal/mol and 6a: 70 kcal/
mol) was shown to be more stable than the corresponding (Z)-
diastereomer (5a: 95 kcal/mol and 6a: 75 kcal/mol).
Finally, among these analogs (5a–p), 3-chlorophenyl
derivative (5d) showed the most potent anti-inflammatory
activity relative to the niflumic acid as the reference drug
(76 and 70 % reduction in inflammation at 1-h postdrug
administration, respectively).
The effect of substitution of 3-trifluoromethylphenyl
moiety with methyl group was next investigated. The anal-
ysis of results allowed us to suggest that most of the
N–CH3 analogs revealed respectable anti-inflammatory
activities (54–80 %).
In the N–CH3 series (6a–f), the compound having
4-pyridyl moiety attached to the imine functional group of
nicotinic acid hydrazide derivative (6f) was the most active
anti-inflammatory agent (80 % reduction in inflammation
at 1-h postdrug administration).
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Med Chem Res (2013) 22:2411–2420
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has been presented by molecular simplification of niflumic
acid through replacing the N-aryl group with N-methyl group.
Biological assay of these compounds exhibited a quiet similar
manner to those of their parent derivatives. Selected com-
pounds were subjected for writhing test and 4-methoxy
derivative (5j) showed the most potent analgesic activity.
Therefore, this new scaffold can be considered as a new lead
for anti-inflammatory and analgesic agents.
Table 2 Analgesic activities of some of the 5 and 6 derivatives
Compound
R
Number of writhinga Inhibition
(%)
CMC
48.75 5.73
5a
H
16.5 2.3*
18.6 5.9*
1.25 0.75***
9.4 2.3**
23.7 3.7*
7.0 1.9**
4.6 1.5***
15.45 6.9**
66.15*b
61.85*
5d
3-ClC6H4
4-OCH3C6H4
3,4-(OMe)2C6H3
3-Pyridyl
4-Pyridyl
4-Pyridyl
5j
97.44***
80.72**
51.38*
5l
5o
5p
85.64**
90.56***
68.31**
Experimental protocols
6f
Niflumic acid
Chemistry
* P \ 0.05, ** P \ 0.01, *** P \ 0.001 compared to CMC group
a
Melting points were determined with a Reichert-Jung hot-
stage microscope (Reichert-Jung, Germany) and are uncor-
rected. Infrared spectra were recorded on a Nicolet Magna
The compounds are administered at the dose of 10 mg/kg
b
Analgesic activity relative to niflumic acid. *, ** and *** differed
from control (CMC) group P \ 0.05, P \ 0.01 and P \ 0.001,
respectively
1
550-FT spectrometer (Nicolet, Madison, WI, USA). H-
NMR (400 MHz) spectra were measured on a Varian Unity
plus 400 spectrometer (Zug, Switzerland) in CDCl3 or
DMSO-d6 with TMS as the internal standard, where J (cou-
pling constant) values are estimated in Hertz. Elemental
microanalyses were carried out with a Perkin-Elmer 240-C
apparatus (Perkin-Elmer, Beaconsfield, UK) and were
within 0.4 % of the theoretical values for C, H, and N. All
solvents and reagents were purchased from the Fluka,
Aldrich (UK), or Merck Chemical Company (Germany).
Male NMRI mice and male Wistar rats, used in the analgesic
and anti-inflammatory screens, respectively, were purchased
from Pasteur Institute (Karaj, Iran), and experiments were
carried out using protocols approved by the ethics committee
of Tehran University of Medical Sciences.
Analgesic activity
The compounds which exhibited significant anti-inflam-
matory activities comparable to that of the niflumic acid
were subjected to analgesic assay.
The analgesic activities of the compounds were studied
using acetic acid-induced abdominal constriction test (writh-
ing test) (Whittle, 1964). Qualitative structure–activity
relationship data, acquired using the analgesic assay, showed
that most of the selected arylidene-2-(3-trifluoromethylani-
lino)nicotinic acid hydrazides were able to reduce the
AcOH-induced constrictions with moderate-to-excellent
activity range (51–97 % inhibition) in comparison with ni-
flumic acid as the reference drug (68 % inhibition) (Table 2).
Interestingly, among substituted analog, 4-pyridyl (5p and
6f) and 4-methoxyphenyl (5j) derivatives exhibited the most
potent analgesic activity with 86, 91, and 97 % of inhibition,
respectively, relative to the reference drug niflumic acid with
68 % of inhibition activity. This phenomenon can be
explained by possible hydrogen bond formation between the
nitrogen of 4-pyridyl or C-4 methoxy substituent on the phe-
nyl ring with amino acids of target binding site.
2-(3-(Trifluoromethyl)anilino)nicotinic acid
hydrazide (4a)
To a solution of ethyl 2-(3-trifluoromethylanilino)nicotin-
ate 3a (1 mmol) in 10 ml of ethanol (5 mmol) 100 %
hydrazine monohydrate was added. The reaction mixture
was kept in room temperature for 24 h, and the progress of
the reaction was monitored by TLC. After completion of
the reaction, the solvent was concentrated and the mixture
was cooled. The precipitate obtained was filtered off, and
recrystallized from ethanol affording the desired compound
4a (70 %); m. p.: 146–148 °C.
Conclusion
IR (KBr): 3,308, 3,200 (NH), 1,635 (C=O) cm-1
.
1H-NMR (CDCl3): d 11.05 (bs, 1H, NH, Ph-NH), 10.18
(bs, 1H, NH, hydrazide), 8.36 (dd, J = 4.8, 1.6 Hz, 1H, H6,
Pyr), 8.29 (s, 1H, H2, Ph-NH), 8.06 (dd, J = 7.6, 1.6 Hz,
1H, H4, Pyr), 7.78 (d, J = 8.00 Hz, 1H, H4, Ph-NH), 7.52
(t, J = 8.0 Hz, 1H, H5, Ph-NH), 7.28 (d, J = 8.00 Hz, 1H,
H6, Ph-NH), 6.91 (dd, J = 7.6, 4.8 Hz, 1H, H5, Pyr), 4.65
(bs, 2H, NH, hydrazide).
Various substituted niflumic acid-based NAH derivatives
were synthesized and screened for their potential anti-
inflammatory activities. Most of the compounds have shown
significant anti-inflammatory and analgesic activities. In car-
rageenan-induced rat paw edema assay, 3-chlorophenyl 5d
and 3-pyridyl derivatives 5o exhibited the most potent anti-
inflammatory activity. Then, a new series of NAH derivatives
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Med Chem Res (2013) 22:2411–2420
13C-NMR (DMSO-d6): d 166.98, 154.26, 150.71,
(3-Fluorobenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5b)
141.51, 136.94, 130.27, 130.0 (q, J = 31.25 Hz), 127.76
(q, J = 271.25), 123.10, 118.00, 115.24, 114.88, 111.51.
Anal. Calcd. for C13H11F3N4O: C, 52.71; H, 3.74; N,
18.91. Found: C, 52.88; H, 3.87; N, 18.82.
Yield: 85 %; m. p.: 196–198 °C (ethanol).
IR (KBr) : 3,332, 3,225 (NH), 1,644 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.21 (bs, 1H, NH, Ph-NH), 10.61
(bs, 1H, NH, hydrazide), 8.50–8.41 (m, 2H, H6, Pyr & H,
=CH–), 8.30 (s, 1H, H2, Ph-NH), 8.22 (dd, J = 7.6, 1.6 Hz,
1H, H4, Pyr), 7.89 (d, J = 8.2 Hz, 1H, H4, Ph-NH),
7.68–7.50 (m, 4H, H5, Ph-NH & H2,4,6, Ph), 7.32–7.28 (m,
2H, H6, Ph-NH & H5, Ph), 7.01 (dd, J = 7.6, 4.8 Hz, 1H,
H5, Pyr).
13C-NMR (DMSO-d6): d 164.58, 162.89 (d, J = 242.5
Hz), 154.63, 151.40, 147.73, 141.40, 138.26, 137.16 (d,
J = 7.5 Hz), 131.47 (d, J = 7.5 Hz), 130.21, 129.92 (q,
J = 31.25 Hz), 124.77 (q, J = 270.0 Hz), 124.08, 123.51,
118.26, 117.51 (d, J = 21.25 Hz), 115.74, 114.83, 113.50
(d, J = 22.5 Hz), 111.57.
2-(Methylamino)nicotinic acid hydrazide (4b)
It was prepared according to procedure reported for 4a.
Yield: 56 %; m. p.: 101–104 °C (ethanol).
IR (KBr): 3,395, 3,299, 3,219 (NH), 1,631 (C=O) cm-1
.
1H-NMR (CDCl3): d 9.7 (bs, 1H, NH, hydrazide), 8.14
(d, J = 4.4 Hz, 1H, H6, Pyr), 8.02 (bs, 1H, NH, methyl–
NH), 7.79 (d, J = 7.2 Hz, 1H, H4, Pyr), 6.52 (dd, J = 7.2,
4.4 Hz, 1H, H5, Pyr), 4.14 (bs, 2H, NH, hydrazide), 2.89
(d, J = 4.0 Hz, 3H, CH3).
13C-NMR (DMSO-d6): d 167.78, 158.21, 151.33,
135.98, 110.67, 109.68, 28.05.
Anal. Calcd. for C20H14F4N4O: C, 59.70; H, 3.51; N,
13.93. Found: C, 59.58; H, 3.37; N, 14.09.
Anal. Calcd. for C7H10N4O: C, 50.59; H, 6.07; N, 33.71.
Found: C, 50.38; H, 6.22; N, 33.56.
(4-Fluorobenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5c)
General procedure for preparation of arylidene-2-(3-
trifluoromethylanilino or methylamino) nicotinic acid
hydrazides (5 and 6)
Yield: 92 %; m. p.: 235–237 °C (ethanol).
IR (KBr): 3,347, 3,253 (NH), 1,645 (C=O) cm-1
.
To a solution of 1 mmol of the hydrazide 4 in absolute
ethanol (10 mL) containing one drop of 37 % hydrochloric
acid 1.1 mmol of corresponding aromatic aldehyde deriv-
ative was added. The mixture was stirred at room tem-
perature for 5–24 h, The progress of the reaction was
monitored by TLC. After completion, the reaction mixture
was neutralized with 10 % aqueous sodium carbonate
solution, and the precipitate formed was filtered out and
recrystallized from appropriated solvent.
1H-NMR (CDCl3): d 12.11 (bs, 1H, NH, Ph-NH), 10.60
(bs, 1H, NH, hydrazide), 8.50–8.41 (m, 2H, H6, Pyr & H,
=CH–), 8.31 (s, 1H, H2, Ph-NH), 8.21 (d, J = 7.5 Hz, 1H,
H4, pyr), 7.86 (d, J = 7.5, 1H, H4, Ph-NH), 7.85–7.95 (dd,
J = 5.8, 8.0 Hz, 2H, H3,5, Ph), 7.52 (t, J = 7.5 Hz, 1H, H5,
Ph-NH), 7.37–7.27 (m, 3H, H6, Ph-NH & H2,6, Ph), 7.01
(dd, J = 7.5, 4.5 Hz, 1H, H5, Pyr).
13C-NMR (DMSO-d6): d 164.41, 163.73 (d, J = 246.
25 Hz),154.56, 151.31, 147.98, 141.41, 137.99, 131.17,
130.20, 129.95 (q, J = 31.25 Hz), 129.88 (d, J = 7.5 Hz),
124.77 (q, J = 270.0 Hz), 123.47, 118.24, 116.45 (d,
J = 21.25 Hz), 115.70, 114.84, 111.82.
Benzylidene-2-(3-trifluromethylanilino)nicotinic acid
hydrazide (5a)
Anal. Calcd. for C20H14F4N4O: C, 59.70; H, 3.51; N,
13.93. Found: C, 59.58; H, 3.27; N, 13.82.
Yield: 80 %; m. p.: 182–184 °C (EtOAc/hexane).
IR (KBr): 3,298, 3,196 (NH), 1,639 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.10 (bs, 1H, NH, Ph-NH), 10.61
(bs, 1H, NH, hydrazide), 8.5–8.41 (m, 2H, H6, Pyr &
H, = CH-), 8.31 (s, 1H, H2, Ph-NH), 8.22 (d, J = 7.6 Hz,
1H, H4, Pyr), 7.87 (d, J = 8.0 Hz, 1H, H4, Ph-NH),
7.82–7.74 (m, 2H, H2,6, Ph), 7.58–7.45 (m, 4H, H3,4,5, Ph &
H5, Ph-NH), 7.31 (d, J = 8.0 Hz, 1H, H6, Ph-NH), 7.01
(dd, J = 5.2, 7.6 Hz, 1H, H5, Pyr).
13C-NMR (DMSO-d6): d 164.41, 154.57, 151.30,
149.15, 141.42, 138.00, 134.55, 130.82, 130.21, 129.93
(q, J = 31.25 Hz), 129.37, 127.69, 124.77 (q, J =
271.25 Hz), 123.47, 118.24, 115.70, 114.85, 111.87.
Anal. Calcd. for C20H15F3N4O: C, 62.50; H, 3.93; N,
14.58. Found: C, 62.58; H, 4.07; N, 14.42.
(3-Chlorobenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5d)
Yield: 87 %; m. p.: 202–204 °C (ethanol).
IR (KBr): 3,328, 3,183 (NH), 1,641 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.28 (bs, 1H, NH, Ph-NH), 10.61
(bs, 1H, NH, hydrazide), 8.48–8.40 (m, 2H, H6, Pyr & H,
=CH–), 8.30 (s, 1H, H2, Ph-NH), 8.25 (d, J = 8.00 Hz, 1H,
H4, Pyr), 7.88 (d, J = 8.8 Hz, 1H, H4, Ph-NH), 7.82 (s, 1H,
H2, Ph), 7.72 (d, J = 7.5 Hz, 1H, H6, Ph), 7.58–7.44 (m,
3H, H5, Ph-NH & H4,5, Ph), 7.31 (d, J = 8.0, 1H, H6, Ph-
NH), 7.01 (dd, J = 8.0, 4.8 Hz, 1H, H5, Pyr).
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Med Chem Res (2013) 22:2411–2420
2417
13C-NMR (DMSO-d6): d 164.50, 154.53, 151.19,
147.36, 141.29, 138.27, 136.82, 134.17, 131.23, 130.37,
130.21, 130.22 (q, J = 32.5 Hz), 126.85, 126.36, 124.73
(q, J = 270.0 Hz), 123.62, 118.37, 115.90, 114.78, 111.69.
Anal. Calcd. for C20H14ClF3N4O: C, 57.36; H, 3.37; N,
13.38. Found: C, 57.58; H, 3.21; N, 13.22.
IR (KBr): 3,440, 3,187, 3,149 (OH, NH), 1,664 (C=O)
cm-1
.
1H-NMR (CDCl3): d 12.05 (bs, 1H, NH, Ph-NH), 10.75
(bs, 1H, NH, hydrazide), 9.59 (bs, 1H, OH, Ph), 8.42–8.37
(m, 2H, H6, Pyr & H, =CH–), 8.36–8.25 (m, 2H, H2, Ph-
NH & H4, Pyr), 7.86 (d, J = 8.0 Hz, 1H, H4, Ph-NH), 7.58
(d, J = 8.0 Hz, 2H, H2,6, Ph), 7.54 (t, 1H, J = 8.0 Hz, H5,
Ph-NH), 7.32 (d, J = 8.0 Hz, 1H, H6, Ph-NH), 7.00 (dd,
J = 7.6, 5.2 Hz, 1H, H5, Pyr), 6.87 (d, J = 8.00 Hz, 2H,
(4-Chlorobenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5e)
H
3,5, Ph).
13C-NMR (DMSO-d6): d 163.75, 160.25, 154.11, 149.75,
149.73, 140.89, 138.80, 130.38, 130.07 (q, J = 31.25 Hz),
129.46, 125.45, 124.70 (q, J = 271.25 Hz), 124.15, 118.89,
116.45, 116.28, 114.74, 112.57.
Yield: 83 %; m. p.: 241–243 °C (ethanol).
IR (KBr): 3,344, 3,204 (NH), 1,637 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.20 (bs, 1H, NH, Ph-NH), 10.65
(bs, 1H, NH, hydrazide), 8.48–8.41 (m, 2H, H6, Pyr & H,
=CH–), 8.31 (s, 1H, H2, Ph-NH), 8.21 (d, J = 7.6 Hz, 1H,
H4, pyr), 7.87 (d, J = 8.0 Hz, 1H, H4, Ph-NH), 7.79 (d, 2H,
J = 7.6 Hz, H2,6, Ph), 7.61–7.46 (m, 3H, H5, Ph-NH &
Anal. Calcd. for C20H15F3N4O2: C, 60.00; H, 3.78; N,
13.99. Found: C, 60.12; H, 3.57; N, 14.15.
H
3,5, Ph), 7.30 (d, J = 8.0 Hz, 1H, H6, Ph-NH), 7.00 (dd,
(3,4-Dihydroxybenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5h)
J = 7.6, 5.2 Hz, 1H, H5, Pyr).
13C-NMR (DMSO-d6): d 164.47, 154.60, 151.35,
147.75, 141.40, 138.00, 135.26, 133.50, 130.15, 129.82 (q,
J = 31.25 Hz), 129.43, 129.27, 124.76 (q, J = 270.0 Hz),
123.46, 118.23, 115.74, 114.79, 111.71.
Yield: 61 %; m. p.: 157–159 °C (ethanol).
IR (KBr): 3,150–3,460 (OH, NH), 1,661 (C=O) cm-1
.
1H-NMR (CDCl3): d (ppm) 11.81 (bs, 1H, NH, Ph-NH),
10.70 (bs, 1H, NH, hydrazide), 9.40 (bs, 2H, OH, Ph), 8.40
(d, J = 4.4 Hz, 1H, H6, Pyr), 8.32 (s, 1H, =CH–), 8.24 (s,
1H, H2, Ph-NH), 8.18 (d, J = 7.6 Hz, 1H, H4, Pyr), 7.85
(d, J = 7.6 Hz, 1H, H4, Ph-NH),7.52 (t, J = 7.6 Hz, H5,
Ph-NH), 7.28 (d, 1H, J = 7.6 Hz, H6, Ph-NH), 7.25 (s, 1H,
H2, Ph), 6.99 (dd, J = 7.6, 4.4 Hz, 1H, H5, Pyr), 6.97 (d,
J = 8.0 Hz, 1H, H6, Ph), 6.79 (d, J = 8.0 Hz, 1H, H5, Ph).
13C-NMR (DMSO-d6): d 163.82, 154.27, 150.29,
149.92, 148.76, 146.24, 141.13, 138.43, 130.33, 130.01 (q,
J = 31.25 Hz), 125.94, 124.74 (q, J = 270.0 Hz), 123.87,
121.21, 118.61, 116.13, 114.79, 113.41, 112.41.
Anal. Calcd. for C20H14ClF3N4O: C, 57.36; H, 3.37; N,
13.38. Found: C, 57.20; H, 3.52; N, 13.22.
(3-Hydroxybenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5f)
Yield: 63 %; m. p.: 231–233 °C (ethanol).
IR (KBr): 3,437 (OH), 3,308, 3,202 (NH), 1,643 (C=O)
cm-1
.
1H-NMR (CDCl3): d 12.05 (bs, 1H, NH, Ph-NH), 10.64
(bs, 1H, NH, hydrazide), 9.68 (bs, 1H, OH, Ph), 8.42 (d,
J = 4.8 Hz, 1H, H6, Pyr), 8.36 (s, 1H, =CH–), 8.32 (s, 1H,
H2, Ph-NH), 8.21 (d, J = 7.6 Hz, 1H, H4, pyr), 7.87 (d,
J = 7.6 Hz, 1H, H4, Ph-NH), 7.53 (t, 1H, J = 7.6 Hz, H5,
Ph-NH), 7.34–7.25 (m, 2H, H6, Ph-NH & H5, Ph), 7.23 (s,
1H, H2, Ph), 7.14 (d, J = 7.2 Hz, 1H, H6, Ph), 7.00 (dd,
J = 7.6, 4.8 Hz, 1H, H5, Pyr), 6.86 (d, J = 7.6 Hz, 1H, H4,
Ph).
Anal. Calcd. for C20H15F3N4O3: C, 57.69; H, 3.63; N,
13.46. Found: C, 57.50; H, 3.85; N, 13.33.
(3-Methoxybenzylidene)-2-(3-trifluromethylanilino)
nicotinic acid hydrazide (5i)
Yield: 67 %; m. p.: 183–186 °C (ethanol).
13C-NMR (DMSO-d6): d 164.35, 158.18, 154.54,
151.27, 149.28, 141.41, 138.00, 135.80, 130.42, 130.22,
129.93 (q, J = 30.0 Hz), 124.87 (q, J = 270.0 Hz),
123.49, 119.40, 118.19, 115.70, 114.86, 113.25, 111.91.
Anal. Calcd. for C20H15F3N4O2: C, 60.00; H, 3.78; N,
13.99. Found: C, 59.78; H, 3.87; N, 13.82.
IR (KBr): 3,349, 3,207 (NH), 1,677 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.30 (bs, 1H, NH, Ph-NH), 10.70
(bs, 1H, NH, hydrazide), 8.48 (s, 1H, =CH–), 8.41 (d,
J = 4.4 Hz, 1H, H6, Pyr), 8.34–8.27 (m, 2H, H4, Pyr & H2,
Ph-NH), 7.89 (d, J = 7.2 Hz, 1H, H4, Ph-NH), 7.53 (t,
J = 7.2 Hz, 1H, H5, Ph-NH), 7.39 (t, J = 8.0 Hz, 1H, H5,
Ph), 7.34–7.27 (m, 3H, H6, Ph-NH & H2, 6, Ph), 7.65–6.98
(m, 2H, H5, Pyr & H4, Ph-NH), 4.54 (s, 3H, OCH3).
13C-NMR (DMSO-d6): d 164.25, 160.03, 154.34,
150.62, 149.09, 141.12, 138.61, 136.01, 130.49, 130.30,
129.99 (q, J = 30.0 Hz), 124.74 (q, J = 272.5 Hz), 123.89,
(4-Hydroxybenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5g)
Yield: 59 %; m. p.: 150–153 °C (ethanol).
123

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Med Chem Res (2013) 22:2411–2420
120.71, 118.63, 117.03, 116.17, 114.80, 112.09, 111.57,
55.65.
(s, 1H, =CH–), 8.30 (s, 1H, H2, Ph-NH), 8.20 (d,
J = 8.00 Hz, 1H, H4, Pyr), 7.88 (d, J = 7.6 Hz, 1H, H4,
Ph-NH), 7.52 (t, J = 7.6 Hz, 1H, H5, Ph-NH), 7.37 (s, 1H,
H2, Ph), 7.29 (d, J = 7.6 Hz, 1H, H6, Ph-NH), 7.22 (d,
J = 8.4 Hz, 1H, H6, Ph), 7.06–6.8 (m, 2H, H5, Pyr & H5,
Ph), 3.83 (s, 3H, OCH3), 3.82 (s, 3H, OCH3).
13C-NMR (DMSO-d6): d 164.17, 154.53, 151.45,
151.15, 149.58, 149.31, 141.45, 137.90, 130.21, 129.93 (q,
J = 31.25 Hz), 127.22, 124.78 (q, J = 270.0 Hz), 123.40,
122.70, 118.18, 115.65, 114.83, 114.83, 112.02, 111.93,
108.57, 56.05, 55.91.
Anal. Calcd. for C21H17F3N4O2: C, 60.87; H, 4.14; N,
13.52. Found: C, 60.72; H, 3.97; N, 13.69.
(4-Methoxybenzylidene)-2-(3-trifluromethylanilino)
nicotinic acid hydrazide (5j)
Yield: 73 %, m. p.: 210–213 °C (ethanol).
IR (KBr): 3,364, 3,271 (NH), 1,645 (C=O) cm-1
.
1H-NMR (CDCl3): d 11.98 (bs, 1H, NH, Ph-NH), 10.66
(bs, 1H, NH, hydrazide), 8.41 (d, J = 4.8 Hz, 1H, H6, Pyr),
8.38 (s, 1H, =CH–), 8.31 (s, 1H, H2, Ph-NH), 8.20 (d,
J = 6.4 Hz, 1H, H4, Pyr), 7.87 (d, J = 8.0 Hz, 1H, H4, Ph-
NH), 7.70 (d, J = 8.4 Hz, 2H, H2,6, Ph), 7.52 (t,
J = 8.0 Hz, 1H, H5, Ph-NH), 7.29 (d, J = 8.0 Hz, 1H, H6,
Ph-NH), 7.10–6.93 (m, 3H, H3,5, Ph & H5, Pyr), 3.82 (s,
3H, OCH3).
Anal. Calcd. for C22H19F3N4O3: C, 59.46; H, 4.31; N,
12.61. Found: C, 59.23; H, 4.17; N, 12.70.
(3,4,5-Trimethoxybenzylidene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5 m)
Yield: 81 %; m. p.: 203–206 °C (ethanol).
13C-NMR (DMSO-d6): d 164.19, 161.52, 154.56,
151.15, 149.07, 141.45, 137.89, 130.20, 130.01 (q,
J = 31.25 Hz), 129.33, 127.09, 124.78 (q, J = 270.0 Hz),
123.40, 118.18, 115.64, 114.86, 111.96, 55.78.
IR (KBr): 3,371, 3,212 (NH), 1,640 (C=O) cm-1
.
1H-NMR (CDCl3): d 10.40 (bs, 1H, NH, Ph-NH), 9.10
(bs, 1H, NH, hydrazide), 8.41 (d, J = 4.8 Hz, 1H, H6, Pyr),
8.20–8.08 (m, 2H, H2, Ph-NH & H, =CH–), 7.96–7.78 (m,
2H, H4, Pyr & H4, Ph-NH), 7.42 (t, 1H, J = 8.0 Hz, H5,
Ph-NH), 7.29 (d, J = 7.6 Hz, 1H, H6, Ph-NH), 6.98 (s, 2H,
Anal. Calcd. for C21H17F3N4O2: C, 60.87; H, 4.14; N,
13.52. Found: C, 61.05; H, 4.01; N, 13.67.
H
2,6, Ph), 6.81 (dd, J = 7.6, 4.8 Hz, 1H, H5, Pyr), 3.92 (s,
(2,4-Dimethoxybenzylidene)-2-(3-trifluromethylanilino)
nicotinic acid hydrazide (5k)
6H, OCH3), 3.90 (s, 3H, OCH3).
13C-NMR (DMSO-d6): d 165.59, 154.70, 153.59,
150.08, 148.94, 141.95, 139.37, 138.33, 130.98, 130.17,
129.92 (q, J = 31.25 Hz), 124.85 (q, J = 270.0 Hz),
123.04, 117.64, 115.13, 114.71, 104.74, 60.55, 56.38.
Anal. Calcd. for C23H21F3N4O4: C, 58.23; H, 4.46; N,
11.81. Found: C, 58.38; H, 4.27; N, 11.97.
Yield: 57 %; m. p.: 181–184 °C (ethanol).
IR (KBr): 3,306, 3,208 (NH), 1,635 (C=O) cm-1
.
1H-NMR (CDCl3): d 11.94 (bs, 1H, NH, Ph-NH), 10.74
(bs, 1H, NH, Pyr), 8.71 (s, 1H, =CH–), 8.40 (dd, J = 4.8,
1.6 Hz, 1H, H6, Pyr), 8.31 (s, 1H, H2, Ph-NH), 8.23 (dd,
J = 7.6, 1.6 Hz, 1H, H4, Pyr), 7.90–7.81 (m, 2H, H4, Ph-
NH & H6, Ph), 7.53 (t, J = 8.0 Hz, 1H, H5, Ph-NH), 7.30
(d, J = 8.00 Hz, 1H, H6, Ph-NH), 6.99 (dd, J = 7.6,
4.8 Hz, 1H, H5, Pyr), 6.70–6.61 (m, 2H, H2,4, Ph), 3.87 (s,
3H, OCH3), 3.83 (s, 3H, OCH3).
4-Dimethylaminobenzylidene-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5n)
Yield: 81 %; m. p.: 225–226 °C (ethanol).
IR (KBr): 3,327, 3,207 (NH), 1,640 (C=O) cm-1
.
13C-NMR (DMSO-d6): d 164.08, 163.09, 159.76,
154.59, 150.97, 144.68, 141.50, 137.87, 130.22, 129.93 (q,
J = 31.25 Hz), 127.15, 124.78 (q, J = 270.0 Hz), 123.30,
118.07, 115.50, 115.40, 114.79, 112.02, 106.94, 98.77,
56.25, 55.91.
1H-NMR (CDCl3): d 11.80 (bs, 1H, NH, Ph-NH), 10.75
(bs, 1H, NH, hydrazide), 8.40 (d, J = 4.4 Hz, 1H, H6, Pyr),
8.32–8.25 (m, 2H, H2, Ph-NH & H, =CH–), 8.18 (d,
J = 8.0 Hz, 1H, H4, Pyr), 7.86 (d, J = 7.6 Hz, 1H, H4, Ph-
NH), 7.56 (d, J = 8.4 Hz, 2H, H2,6, Ph), 7.52 (t,
J = 7.6 Hz, 1H, H5, Ph-NH), 7.28 (d, J = 7.6 Hz, 1H, H6,
Ph-NH), 6.99 (dd, J = 8.0, 4.4 Hz, 1H, H5, Pyr), 6.77 (d,
J = 8.4 Hz, 2H, H3,5, Ph), 2.99 (s, 6H, –N(CH3)2).
13C-NMR (DMSO-d6): d 165.18, 154.71, 151.70,
149.84, 149.57, 142.14, 138.03, 130.19, 129.95, (q,
J = 31.25 Hz), 128.95, 124.88 (q, J = 270.0 Hz), 122.82,
122.80, 117.39, 114.87, 114.67, 112.25, 40.30.
Anal. Calcd. for C22H19F3N4O3: C, 59.46; H, 4.31; N,
12.61. Found: C, 59.60; H, 4.47; N, 12.48.
(3,4-Dimethoxybenzylidene)-2-(3-trifluromethylanilino)
nicotinic acid hydrazide (5l)
Yield: 71 %; m. p.: 197–199 °C (ethanol).
IR (KBr): 3,334, 3,230 (NH), 1,635 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.00 (bs, 1H, NH, Ph-NH), 10.70
(bs, 1H, NH, hydrazide), 8.41 (d, J = 4.8 1H, H6, Pyr), 8.36
Anal. Calcd. for C22H20F3N5O: C, 61.82; H, 4.72; N,
16.39. Found: C, 61.68; H, 4.87; N, 16.22.
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2419
(Pyridin-3-ylmethylene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5o)
Anal. Calcd. for C14H14N4O: C, 66.13; H, 5.55; N,
22.03. Found: C, 66.28; H, 5.37; N, 22.21.
Yield: 87 %; m. p.: 195–197 °C (ethanol).
(3-Chlorobenzylidene)-2-(methylamino)nicotinic acid
hydrazide (6b)
IR (KBr): 3,320, 3,215 (NH), 1,642 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.27 (bs, 1H, NH, Ph-NH), 10.58
(bs, 1H, NH, hydrazide), 8.90 (s, 1H, H2, Pyr2), 8.64 (d,
J = 4.4 Hz, 1H, H6, Pyr2), 8.50 (s, 1H, 1-CH=), 8.44
(d, J = 4.4 Hz, H6, Pyr1), 8.31 (s, 1H, H2, Ph-NH), 8.23 (d,
J = 7.6 Hz, 1H, H4, Pyr1), 8.18 (d, J = 7.6 Hz, 1H, H4,
Pyr2), 7.89 (d, J = 8.0 Hz, 1H, H4, Ph-NH), 7.61–7.45 (m,
2H, H5, Pyr2 & H5, Ph-NH), 7.31 (d, J = 8.0 Hz, 1H, H6,
Ph-NH), 7.03 (dd, J = 7.6, 4.4 Hz, 1H, H5, Pyr1).
13C-NMR (DMSO-d6): d 164.55, 154.61, 151.40,
151.24, 149.22, 146.32, 141.36, 138.02, 134.07, 130.50,
130.11, 130.02 (q, J = 31.25 Hz), 124.75 (q,
J = 270.0 Hz), 124.47, 123.47, 118.23, 115.77, 114.76,
111.53.
Yield: 53 %; m. p.: 201–204 °C (butanol/EtOAc).
IR (KBr): 3,281, 3,185 (NH), 1,686 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.80 (bs, 1H, NH, hydrazide),
9.10 (bs, 1H, NH, –NHCH3), 8.55 (s, 1H, –CH=), 8.51 (d,
J = 5.6 Hz, H6, Pyr), 8.15 (d, J = 7.2 Hz, 1H, H4, Pyr),
7.79 (s, 1H, H2, Ph), 7.70 (d, J = 7.5 Hz, 1H, H6, Ph),
7.56–7.4 (m, 2H, H4,5, Ph), 6.96 (dd, J = 7.2, 5.6 Hz, 1H,
H5, Pyr), 3.08 (s, 3H, CH3).
13C-NMR (DMSO-d6): d 162.16, 153.06, 148.22,
142.41, 136.70, 135.33, 134.17, 133.40, 131.33, 130.50,
129.40, 126.87, 126.37, 29.95.
Anal. Calcd. for C14H13ClN4O: C, 58.24; H, 4.54; N,
19.40. Found: C, 58.36; H, 4.67; N, 19.54.
Anal. Calcd. for C19H14F3N5O: C, 59.22; H, 3.66; N,
18.17. Found: C, 59.38; H, 3.87; N, 18.02.
(4-Chlorobenzylidene)-2-(methylamino)nicotinic acid
hydrazide (6c)
(Pyridin-4-ylmethylene)-2-(3-trifluoromethylanilino)
nicotinic acid hydrazide (5p)
Yield: 72 %; m. p.: 221–223 °C (butanol/EtOAc).
IR (KBr): 3,350, 3,276 (NH), 1,674 (C=O) cm-1
.
Yield: 83 %; m. p.: 245–248 °C (ethanol).
IR (KBr): 3,345, 3,257 (NH), 1,645 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.53 (bs, 1H, NH, hydrazide),
8.99 (bs, 1H, NH, -NHCH3), 8.51 (s, 1H, –CH=), 8.43 (d,
J = 5.2 Hz, 1H, H6, Pyr), 8.13 (d, J = 7.2 Hz, 1H, H4,
Pyr), 7.75 (d, J = 7.5 Hz, 2H, H2,6, Ph), 7.53 (d,
J = 7.5 Hz, 2H, H3,5, Ph), 6.95 (dd, J = 7.2, 5.2 Hz, 1H,
H5, Pyr), 3.04 (s, 3H, CH3).
1H-NMR (CDCl3): d 12.36 (bs, 1H, NH, Ph-NH), 10.53
(bs, 1H, NH, hydrazide), 8.60 (d, J = 4.0 Hz, 2H, H2,6
,
Pyr2), 8.45–8.38 (m, 2H, H6, Pyr1 & 1H, –CH=), 8.31 (s,
1H, H2, Ph-NH), 8.23 (d, J = 7.6 Hz, 1H, H4, Pyr1), 7.88
(d, J = 8.0 Hz, 1H, H4, Ph-NH), 7.71 (d, J = 4.0 Hz, 2H,
13C-NMR (DMSO-d6): d 161.96, 152.86, 148.27,
142.49, 140.95, 135.34, 133.39, 129.51, 129.30, 115.41,
111.17, 30.03.
H
3,5, Pyr2), 7.53 (t, J = 8.0 Hz, 1H, H5, Ph-NH), 7.32 (d,
J = 8.0 Hz, 1H, H6, Ph-NH), 7.03 (dd, J = 7.6, 4.4 Hz,
1H, H5, Pyr1).
13C-NMR (DMSO-d6): d 165.99, 154.78, 150.63,
146.49, 142.44, 141.76, 138.61, 130.16, 129.81 (q,
J = 31.25 Hz), 124.78 (q, J = 270.0 Hz), 123.26, 121.46,
117.86, 115.38, 114.75, 113.20.
Anal. Calcd. for C14H13ClN4O: C, 58.24; H, 4.54; N,
19.40. Found: C, 58.38; H, 4.41; N, 19.22.
(3-Methoxybenzylidene)-2-(methylamino)nicotinic acid
hydrazide (6d)
Anal. Calcd. for C19H14F3N5O: C, 59.22; H, 3.66; N,
18.17. Found: C, 59.08; H, 3.47; N, 17.98.
Yield: 47 %; m. p.: 175–177 °C (butanol).
IR (KBr): 3,412, 3,185 (NH), 1,630 (C=O) cm-1
.
Benzylidene-2-(methylamino)nicotinic acid
hydrazide (6a)
1H-NMR (CDCl3): d 11.90 (bs, 1H, NH, hydrazide),
8.36 (s, 1H, =CH–), 8.22 (d, J = 4.8 Hz, 1H, H6, Pyr),
8.00–7.9 (m, 2H, H4, Pyr & H, –NHCH3), 7.37 (t,
J = 7.6 Hz, 1H, H5, Ph), 7.27 (m, 2H, H2,6, Ph), 7.01 (d,
J = 7.6 Hz, 1H, H4, Ph), 6.61 (dd, J = 7.2, 4.8 Hz, 1H,
H5, Pyr), 3.80 (s, 3H, OCH3), 2.90 (s, 3H, CH3).
13C-NMR (DMSO-d6): d 164.74, 160.00, 158.45,
151.98, 147.86, 137.01, 136.25, 130.43, 120.49, 116.66,
111.54, 110.63, 109.74, 55.61, 28.22.
Yield: 63 %; m. p.: 231–234 °C (butanol).
IR (KBr): 3,346, 3,272 (NH), 1,675 (C=O) cm-1
.
1H-NMR (CDCl3): d 8.42 (s, 1H, –CH=), 8.21 (d,
J = 4.8 Hz, 1H, H6, Pyr), 8.04–7.98 (m, 2H, H4, Pyr & H,
NHCH3), 7.70 (m, 2H, H2,6, Ph), 7.49–7.41 (m, 3H, H3,4,5
,
Ph), 6.6 (dd, J = 7.6, 4.8 Hz, 1H, H5, Pyr), 2.92 (s, 3H, CH3).
13C-NMR (DMSO-d6): d 162.05, 153.26, 149.48,
141.96, 134.43, 130.91, 129.41, 127.68, 127.08, 115.32,
111.14, 29.71.
Anal. Calcd. for C15H16N4O2: C, 63.37; H, 5.67; N,
19.71. Found: C, 63.58; H, 5.80; N, 19.52.
123

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Med Chem Res (2013) 22:2411–2420
Duarte CD, Tributino JLM, Lacerda DI, Martins MV, Alexandre-Moreira
MS, Dutra F, Bechara EJH, De-Paula FS, Goulart MOF, Ferreira J,
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pyrimidinediamines. US Pat Appl US 4(983):608
(Pyridin-3-ylmethylene)-2-(methylamino)nicotinic acid
hydrazide (6e)
Yield: 55 %; m. p.: 173–175 °C (ethanol).
IR (KBr): 3,483, 3,351 (NH), 1,639 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.00 (bs, 1H, NH, hydrazide), 8.85
(s, 1H, H2, Pyr2), 8.61 (d, J = 4.4 Hz, 1H, H6, Pyr2), 8.43
(s, 1H, =CH–), 8.24 (d, J = 4.8 Hz, 1H, H6, Pyr1), 8.12 (d,
J = 7.2 Hz, 1H, H4, Pyr1), 7.98 (d, J = 7.2 Hz, 1H, H4,
Pyr1), 7.49 (dd, J = 4.4, 7.2 Hz, 1H, H5, Pyr2), 6.63
(dd, J = 4.8, 7.2 Hz, 1H, H5, Pyr1), 2.92 (d, J = 4.00 Hz,
3H, CH3).
˜
Figueiredo JM, CaA mara CA, Amarante EG, Miranda ALP, Santos FM,
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Novel synthesis of [1]-benzothiepino[5,4-b]pyridine-3-carbonitr-
iles and their anti-inflammatory properties. Bioorg Med Chem
15:2403–2413
13C-NMR (DMSO-d6): d 164.13, 157.09, 150.79,
148.74, 145.42, 138.48, 134.37, 130.80, 129.44, 129.16,
124.68, 110.79, 28.65.
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Anal. Calcd. for C13H13N5O: C, 61.17; H, 5.13; N,
27.43. Found: C, 61.38; H, 5.02; N, 27.60.
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new class of 2-anilino substituted nicotinyl arylsulfonylhydraz-
ides as potential anticancer and antibacterial agents. Bioorg Med
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Lima PC, Lima LM, Da Silva KCM, Leda PHO, Miranda ALP, Fraga
CAM, Barreiro EJ (2000) Synthesis and analgesic activity of
novel N-acylarylhydrazones and isosters, derived from natural
safrole. Eur J Med Chem 15:2421–2433
Moradi A, Navidpour L, Amini M, Sadeghian H, Shadnia H, Firouzi
O, Miri R, Ebrahimi SES, Abdollahi M, Zahmatkesh MH,
Shafiee A (2010) Design and synthesis of 2-phenoxynicotinic
acid hydrazides as anti-inflammatory and analgesic agents. Arch
Pharm Chem Life Sci 9:509–518
(Pyridin-4-ylmethylene)-2-(methylamino)nicotinic acid
hydrazide (6f)
Yield: 71 %; m. p.: 274–277 °C (ethanol).
IR (KBr): 3,425, 3,281 (NH), 1,672 (C=O) cm-1
.
1H-NMR (CDCl3): d 12.70 (bs, 1H, NH, hydrazide),
8.80 (m, 3H, H2,6, Pyr2 & H, NH, –NHCH3), 8.50 (s, 1H,
=CH–), 8.24 (d, J = 4.8 Hz, 2H, H6, Pyr1), 8.05–7.90 (m,
3H, H4, Pyr1 & H3,5, Pyr2), 6.82 (dd, J = 4.8, 7.2 Hz, 1H,
H5, Pyr1), 2.99 (s, 3H, CH3).
13C-NMR (DMSO-d6): d 164.72, 158.76, 151.29,
147.93, 144.76, 136.28 129.27, 123.56, 111.02, 49.13.
Anal. Calcd. for C13H13N5O: C, 61.17; H, 5.13; N,
27.43. Found: C, 60.98; H, 5.29; N, 27.22.
Acknowledgments This work was supported by a Grant from Drug
Design & Development Research Center.
Ribeiro IG, da Silva KCM, Parrinil SC, de Miranda ALP, Fraga
CAM, Barreiro EJ (1998) Synthesis and antinociceptive prop-
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Smith CJ, Zhang Y, Koboldt CM, Muhammad J, Zweifel BS, Shaffer
A, Talley JJ, Masaferrer JL, Seibert K, Isakson PG (1998)
Pharmacological analysis of cyclooxygenase-1 in inflammation.
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