Synthesis, cyclooxygenase inhibition, and anti-inflammatory evaluation of novel diarylheterocycles with a central pyrazole, pyrazoline, or pyridine ring

Article abstract of DOI:10.1007/s00044-015-1327-7

Five groups of diarylheterocycles with a central pyrazole ring (12a-d), pyrazoline ring (14a-d), or pyridine ring (15a-d, 16a-d and 17a-d) were synthesized and evaluated in vitro for COX-1/COX-2 inhibitory activity and in vivo for anti-inflammatory activity. All compounds that possessed anti-inflammatory activity were assessed for their ulcerogenic liability in comparison with ibuprofen and celecoxib. The pyrazole derivative 12b and the pyrazoline derivative 14b were the least ulcerogenic compounds with relative ulcerogenicities to celecoxib 0.85 and 0.90 respectively. (Chemical Equation Presented)

Full text of DOI:10.1007/s00044-015-1327-7

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-015-1327-7
ORIGINAL RESEARCH
Synthesis, cyclooxygenase inhibition, and anti-inflammatory
evaluation of novel diarylheterocycles with a central pyrazole,
pyrazoline, or pyridine ring
•
Khaled R. A. Abdellatif Eman K. A. Abdelall
•
•
Wael A. A. Fadaly Gehan M. Kamel
Received: 30 September 2014 / Accepted: 17 January 2015
Ó Springer Science+Business Media New York 2015
Abstract Five groups of diarylheterocycles with a central
pyrazole ring (12a–d), pyrazoline ring (14a–d), or pyridine
ring (15a–d, 16a–d and 17a–d) were synthesized and
evaluated in vitro for COX-1/COX-2 inhibitory activity
and in vivo for anti-inflammatory activity. All compounds
that possessed anti-inflammatory activity were assessed for
their ulcerogenic liability in comparison with ibuprofen
and celecoxib. The pyrazole derivative 12b and the pyr-
azoline derivative 14b were the least ulcerogenic com-
pounds with relative ulcerogenicities to celecoxib 0.85 and
0.90 respectively.
Graphical Abstract
X
Ar
Ar
X
X
N
N
N
CN
SO2R1
N
O
R2
N
H3C
F3C
X = O, S; R1 = CH3, NH2; Ar = 3-pyridyl, 4-pyridyl; R2 = NH2, OH, OCH3
Keywords Diarylheterocycles ꢀ Pyrazole ꢀ Pyrazoline ꢀ
Cyanopyridine ꢀ Cyclooxygenase-2 ꢀ
Anti-inflammatory activity
Electronic supplementary material The online version of this
article (doi:10.1007/s00044-015-1327-7) contains supplementary
material, which is available to authorized users.
Introduction
K. R. A. Abdellatif (&) ꢀ E. K. A. Abdelall ꢀ W. A. A. Fadaly
Pharmaceutical Organic Chemistry Department, Faculty of
Pharmacy, Beni-Suef University, Beni Suef, Egypt
e-mail: khaled.ahmed@pharm.bsu.edu.eg
The anti-inflammatory activity of non-steroidal anti-
inflammatory drugs (NSAIDs) was attributed to enzymatic
inhibition of cyclooxygenase (COX)-mediated production
of pro-inflammatory prostaglandins (PGs) and thrombox-
anes (TXs) (Abdelazeem et al., 2014; Zebardast et al.,
2009). Cyclooxygenase enzyme exists in two distinct
G. M. Kamel
Pharmacology Department, Faculty of Veterinary, Cairo
University, Cairo, Egypt
123

Med Chem Res
isoforms, a constitutive form (COX-1) and an inducible
form (COX-2); the beneficial anti-inflammatory and anal-
gesic effects of NSAIDs have been linked to inhibition of
COX-2, while the adverse gastrointestinal irritation and
ulcerative effects are believed to be mainly due to inhibi-
tion of COX-1 (Abdellatif et al., 2009). For this reason,
selective COX-2 inhibitor drugs (coxibs) such as celecoxib
(1), rofecoxib (2), valdecoxib (3), and etoricoxib (4) have
been developed for the treatment of patients suffering from
chronic inflammation (Hinz and Brune, 2002). Unfortu-
nately, evidence began to accumulate suggesting that
highly selective COX-2 inhibitors alter the balance in the
COX pathway causing a decrease in the level of the
desirable vasodilatory and anti-aggregatory prostacyclin
(PGI2) in conjunction with an increase in the level of the
undesirable prothrombotic thromboxane A2 (TxA2). This
alteration was believed to be responsible for the increased
incidences of high blood pressure and myocardial infarc-
tion that caused the withdrawal of rofecoxib and valdec-
oxib from the market (Dogne et al., 2005; Scheen, 2004).
So that, there is still a strong need for the development of
effective anti-inflammatory drugs with improved safety
profiles over the existing NSAIDs. In this regard, we
reported some coxibs (5–9) of comparable activity with
celecoxib and rofecoxib as COX-2 selective compounds
(Abdellatif et al., 2008a, 2008b, 2008c; Chowdhury et al.,
2008a, 2008b) (Fig. 1).
The majority of selective COX-2 inhibitors are di-
arylheterocycles, in which two vicinal (adjacent) aryl
substituents attached to a five-membered ring as pyra-
zole in celecoxib (1), furanone in rofecoxib (2), isox-
azole in valdecoxib (3), or attached to a six-membered
ring as pyridine in etoricoxib (4). In continuation with
our work related to synthesis of safe anti-inflammatory
agents, we now describe the synthesis, in vitro evalua-
tion as COX-1/COX-2 inhibitors and in vivo anti-
inflammatory (AI) activity for five groups of diarylhet-
erocycles 12a–d, 14a–d, 15a–d, 16a–d, and 17a–d in
which the two aryl rings are as follows: (i) vicinal (1,5-
diaryl) and attached to a five-membered pyrazole ring
(12a–d), (ii) not vicinal (3,5-diaryl) and attached to a
five-membered pyrazoline ring (14a–d) or (iii) not vic-
inal (3,5-diaryl) and attached to a six-membered pyri-
dine ring (15a–d, 16a–d, and 17a–d).
Fig. 1 Chemical structures of
some selective cyclooxygenase-
2 (COX-2) inhibitors (1–9)
Me
SO2NH2
SO2Me
SO2NH2
N
O
N
O
O
N
Me
Rofecoxib (2)
Valdecoxib (3)
Celecoxib (1)
F3C
R
NHR1
SO2Me
Cl
SO2Me
SO2R2
N
N
N
N
N
HOOC
N
Me
R = H, F, Me
5
R1 = Me, Et; R2 = Me, NH2
F3C
Etoricoxib (4)
6
CH2OH
OH
H
N
N
O
SO2R
SO2R
SO2R
N
N
N
N
N
N
F3C
F3C
F3C
R = Me, NH2
7
R = Me, NH2
8
R = Me, NH2
9
123

Med Chem Res
Scheme 1 Synthetic protocol
for compounds 12a–d. Reagents
and conditions: a EtOH, reflux,
24 h
NHNH2.HCl
X
CF3
a
X
SO2R
O
N
O
N
SO2R
11a-b
F3C
12a-d
10a-b
10a; X = O, 10b; X = S
12a; X = O, R = NH2 12b; X = O, R = CH3
12c; X = S, R = NH2 12d; X = S, R = CH3
11a; R = NH2, 11b; R = CH3
Scheme 2 Synthetic protocol
for compounds 14a–d, 15a–d,
16a–d and 17a–d. Reagents and
conditions: a hydrazine hydrate,
glacial acetic acid, reflux, 36 h;
b Malononitrile, ammonium
acetate, ethanol, reflux, 20 h;
c ethylcyanoacetate, ammonium
acetate, reflux, 18 h;
a
Ar
O
X
N
N
14a-d
H3C
d malononitrile, NaOCH3,
methanol, RT, 24 h
Ar
b
X
N
Ar
CN
15a-d
NH2
X
O
13a-d
Ar
a; Ar = 3-pyridyl, X = O
b; Ar = 4-pyridyl, X = O
c; Ar = 3-pyridyl, X = S
d; Ar = 4-pyridyl, X = S
c
X
N
CN
16a-d
OH
Ar
d
X
N
CN
17a-d
OCH3
Results and discussion
analog 12a (48 %), 12b (33 %) or 12d (29 %) as shown in
Scheme 1.
Chemistry
Also, another four groups of diarylheterocycles 14a, c and
d, 15a–d, 16a–d, and 17a–d were synthesized using the
reaction sequence illustrated in Scheme 2. Accordingly,
cyclization of the chalcones 13a,c,d with hydrazine hydrate in
the presence of glacial acetic acid gave the respective 3,5-
diaryl-pyrazolines 14a,c,d in high yields (61–74 %), while
Reaction of the dione 10a–b with either 4-aminosulfonyl-
phenylhydrazine hydrochloride (11a) or 4-methylsulfo-
nylphenylhydrazine hydrochloride (11b) in ethanol under
reflux conditions afforded the respective 1,5-diarylpyrazole
123

Med Chem Res
Anti-inflammatory activity
reactionofchalcones13a–d with malononitrile in thepresence
of ammonium acetate yielded the respective aminocyano-
pyridine derivatives 15a–d in considerable yields (45–66 %).
Moreover, cyclization of 13a–d with ethylcyanoacetate or
malononitrile in presence of sodium methoxide afforded the
corresponding 2-oxo-3-cyano-pyridines 16a–d (36–55 %) or
2-methoxy-3-cyano-pyridines 17a–d (42–66 %) respectively.
All the prepared compounds have been characterized by
IR, 1H NMR, 13CNMR, massspectra, andelementalanalyses.
The IR spectra of the amino(methane)sulphonylpyrazole
derivatives12a,b,d showedtheappearanceoftwosharppeaks
at 1,345–1,321 and 1,155–1,150 cm-1 corresponding to SO2,
while the IR spectra of the acetylpyrazolines 14a,c,d dis-
played a sharp peak at 1,637–1,642 cm-1 corresponding to
C=O. Additionally, The IR spectra of the cyanopyridine
derivatives 15a–d, 16a–d and 17a–d showed a sharp peak at
2,223–2,183 cm-1 corresponding to C:N in addition to a
forked peak at 3,443–3,386 and 3,390–3,320 cm-1 corre-
sponding to NH2 for the amino derivatives 15a–d and a broad
peak at 3,416–3,430 cm-1 corresponding to OH in case of
In vitro cyclooxygenase (COX) inhibition assay
The target of the in vitro biological activity tests was to
study the ability of tested compounds to inhibit ovine
COX-1 and human recombinant COX-2 using an enzyme
immunoassay (EIA) kit. The potency of tested compounds
was determined as the concentration causing 50 % enzyme
inhibition (IC50). Also, the COX-2 selectivity indexes (SI
values) which are defined as IC50 (COX-1)/IC50 (COX-2)
were calculated and compared with that of the standard
drugs: celecoxib, aspirin, and ibuprofen.
The results for the 20 synthesized compounds 12a–d, 14a–
d, 15a–d, 16a–d, and 17a–d revealed that all compounds were
more selective COX-2 inhibitors (SI = 4.6 - 8.4) than aspi-
rin (SI = 0.1) andibuprofen (SI = 2.6) but were less selective
than celecoxib (SI = 110). The pyrazoles (12a–d) and pyr-
azolines (14a–d) showed the highest COX-2 selectivity
indexes (4.7–7.4 and 4.3–8.4, respectively), whereas the cya-
nopyridine analogs (15a–d, 16a–d, and 17a–d) showed COX-
2 selectivity indexes of 4.4–6.7 (see data in Table 1).
1
the hydroxy derivatives 16a–d. The H NMR spectra of
the 1,5-diaryl-3-trifluoromethyl-1H-pyrazole derivatives
12a,b,d showedasingletofone-protonintensityinthe range d
6.28–6.80 corresponding to pyrazole H-4, while the 1H NMR
spectra of the pyrazolines 14a,c,d displayed three signals as
doublet of doublet (dd), each of one-proton intensity, first at d
3.10–3.15, second at d 3.47–3.78, and the third at d 5.57–5.62
with three different J values (17.6, 11.6, 4.8 Hz) corre-
sponding to three protons of the dihydropyrazole ring. The
highest J value was due to geminal coupling of two protons at
position 4, while the other two J values due to coupling of two
geminal protons with proton at position 5. Additionally, The
1H NMR spectra of the cyanopyridine derivatives 15a–d,
16a–d, and 17a–d showed a singlet of one-proton intensity in
the range d 6.62–7.72 corresponding to the proton of the
central pyridine ring. The 13C NMR spectra of 12a–d con-
firmed the presence of pyrazole ring by the presence of three
peaksatd105.55–106.86,127.25–134.06,and144.85–151.34
corresponding to pyrazole C-4, C-5, and C-3, respectively, in
addition to a quartet at d 123.74–126.70 with J value =
270 Hz corresponding to C of CF3 while, the 13C NMR
spectra of acetylpyrazolines 14a,c,d confirmed the presence
of the pyrazoline ring due to the presence of three peaks at d
41.72–42.86, 57.38–59.06, and 149.06–150.41 corresponding
to pyrazoline C-4, C-5 and C-3, respectively, in addition to
two peaks at d 21.79–21.93 and 168.90–168.94 corresponding
to two C of acetyl group. Moreover, the 13C NMR spectra of
the cyanopyridine derivatives 15a–d, 16a–d, and 17a–
d showed five peaks at d 90.58–92.56, 111.14–116.21,
147.33–152.95, 150.49–153.69, and 152.12–165.17 corre-
sponding to central pyridine C-3, C-5, C-4, C-6, and C-2,
respectively, in addition to a peak at d 115.03–118.80 corre-
sponding to C of C:N.
In vivo anti-inflammatory activity
The anti-inflammatory (AI) activities exhibited by the
synthesized compounds were determined using a formalin-
induced rat paw edema model. The activities of tested
compounds were determined as the concentration causing
50 % edema inhibition (ED50). The pyrazoles (12a–d) and
pyrazolines (14a–d) exhibited AI activities (ED50
=
328–519 and 428–509 lmol/kg po range, respectively) that
were greater than that exhibited by the reference drug
aspirin (ED50 = 710 lmol/kg po) and of comparable
potency to that of ibuprofen (ED50 = 327 lmol/kg po), but
less than that of celecoxib (ED50 = 30.9 lmol/kg po). The
2-amino-3-cyanopyridine derivatives (15a–d) showed wide
range of AI activity (ED50 = 339–809 lmol/kg po), while
the
2-hydroxy-3-cyanopyridine
derivatives
(16a–
d) showed no or very low AI activity at different doses so
their ED50 cannot be determined. Additionally, the
2-methoxy-3-cyanopyridine derivatives (17a–d) showed
AI activity of ED50 = 279–716 lmol/kg po range. The
relative AI potency profile with respect to the furo and
thieno rings was variable with furo (12a, 12b and 14a,
14b) \ thieno (12c, 12d and 14c, 14d) for the pyrazole and
pyrazoline compounds (12a–d and 14a–d), but furo (15a,
15b) [ thieno (15c, 15d) for the 2-amino-3-cyanopyridine
derivatives (15a–d), while in case of 2-methoxy-3-cyano-
pyridine derivatives 17a–d, the furo analog (17a,
ED50 = 516 lmol/kg) is more potent than the corre-
sponding thieno analog (17c, ED50 = 716 lmol/kg) and
the furo analog (17b, ED50 = 451 lmol/kg) is less potent
123

Med Chem Res
Table 1 In vitro COX-1 and COX-2 inhibition, and anti-inflammatory (AI) data for pyrazoles (12a–d), pyrazolines (14a–d), pyridines (15a–d,
16a–d and 17a–d), and the reference drugs, celecoxib, aspirin, and ibuprofen
Compound
COX-1 IC50 (M)a
COX-2 S.I.b
COX-2 IC50 (M)a
AI activity
Dose (lmol/kg)
Edema inhibition (%)
ED50 (lmol/kg)c
12a
0.18
0.029
6.21
280
350
420
280
351
421
491
202
269
336
201
268
336
403
294
392
490
294
392
490
588
184
276
369
461
184
369
461
286
381
477
190
286
381
359
449
539
719
359
449
539
629
719
285
380
32
384
37.34
53.3
34.67
37.33
41
12b
0.096
0.013
7.39
519
49
12c
12d
0.052
0.074
0.011
0.010
4.73
7.40
36
328
376
42.67
52
36
40
45.25
52
14a
14b
0.201
0.229
0.024
0.038
8.38
6.03
40
447
509
49
52
41.23
45.2
49.33
52
14c
0.027
0.005
5.39
20
428
40
46.67
50.67
33.33
46.67
59
14d
15a
15b
15c
0.448
0.398
0.322
0.141
0.105
0.075
0.054
0.021
4.26
5.31
5.96
6.71
439
431
339
809
34
49.33
56
42
48.67
57.33
29.25
33.25
38.67
46.67
20
15d
16a
0.106
0.309
0.021
0.071
5.07
4.35
665
26.67
36
44
53
0
NDd
0
123

Med Chem Res
Table 1 continued
Compound
COX-1 IC50 (M)a
COX-2 S.I.b
0.008
COX-2 IC50 (M)a
AI activity
Dose (lmol/kg)
Edema inhibition (%)
ED50 (lmol/kg)c
16b
0.051
0.171
0.077
0.232
6.27
190
285
380
358
537
716
179
268
358
270
361
451
541
180
270
361
722
341
511
682
170
255
341
–
0
NDd
6.67
20
16c
16d
17a
0.030
0.015
0.038
5.69
5.11
6.12
22.67
26.67
32
NDd
NDd
516
0
0
6.67
30
38
44
52
17b
0.217
0.043
5.05
30.67
36.67
45.33
60
451
17c
17d
0.156
0.390
0.026
0.080
5.99
4.87
33.34
38.67
49.33
33
716
279
38
60
Celcoxibe
Aspirine
Ibuprofene
a
7.7
0.3
2.9
0.12
2.4
110
–
30.9
714
0.13
2.64
–
–
1.1
–
–
327
The in vitro test compound concentration required to produce 50 % inhibition of COX-1 or COX-2. The result (IC50, lM) is the mean of two
determinations acquired using an ovine COX-1/COX-2 assay kit (Cayman Chemicals Inc., Ann Arbor, MI, USA) and the deviation from the
mean is \10 % of the mean value
b
In vitro COX-2 selectivity index (Cox-1 IC50/Cox-2 IC50
)
c
Inhibitory activity in a formalin-induced rat paw edema assay. The results are expressed as the ED50 value (lmol/kg) at 3 h after oral
administration of the test compound
d
ND = not determined
e
Data quoted from the literature (Chowdhury et al., 2010)
than the corresponding thieno analog (17d, ED50
279 lmol/kg; Table 1).
=
derivative 12b and the pyrazoline derivative 14b were less
ulcerogenic than celecoxib with relative ulcerogenicities
0.85 and 0.90, respectively. In comparison with the tradi-
tional NSAID ibuprofen (25 mg/kg), all the tested com-
pounds were less ulcerogenic with relative ulcerogenicity
range 0.15–0.42.
Ulcerogenic liability
Tested compounds that possess anti-inflammatory activity
and low ulcerogenic reference drug (celecoxib) were sub-
jected to ulcerogenic liability at ED50 dose, and the results
are recorded in Table 2. It was clear that the tested com-
pounds caused ulceration effect comparable to that of
celecoxib since the range of relative ulcerogenicity of the
tested compounds to celecoxib is 0.85–2.41. The pyrazole
Therefore, the potential value for the tested compounds
as anti-inflammatory agents is that they have highly better
safety margin on gastric mucosa than traditional NSAIDs
as ibuprofen. Moreover, compounds 12b and 14b showed
ulcerogenic potential less than the low ulcerogenic drug
(celecoxib). These promising ulcer protective properties of
123

Med Chem Res
Table 2 Ulcerogenic effect of celecoxib, tested compounds in rats (ED50) and ibuprofen (25 mg/kg)
Compound
Average severity
Average no of ulcers
Incidence/10 (%)
Ulcer index
Relative ulcerogenicity to
Celecoxib
Ibuprofen
12a
0.58 0.02**b
0.63 0.024***b
0.75 0.026***b
0.5 0.011b
0.75 0.014***b
0.62 0.015***b
0.62 0.018***b
0.87 0.024***b
1.02 0.09***b
0.92 0.07***b
0.83 0.02***b
0.55 0.08b
0.4 0.01b
0.2 0.006***b
0.4 0.007b
0.4 0.012b
0.8 0.03***b
0.4 0.06b
0.8 0.04***b
1.2 0.13***b
0.8 0.03***b
1.4 0.06***b
0.6 0.04***b
0.4 0.06b
4
2
4.98
2.83
4.7
1.49
0.85
1.40
1.46
2.25
0.90
2.22
2.41
1.14
1.89
1.62
1.45
1.86
1.62
1.74
1.00
6.04
0.26
0.15
0.24
0.25
0.39
0.16
0.39
0.42
0.20
0.33
0.28
0.26
0.32
0.28
0.30
0.17
1.00
12b
12c
4
12d
4
4.9
14a
6
7.55
3.02
7.42
8.07
3.82
6.32
5.43
4.95
6.23
5.43
5.83
3.35
20.25
14b
2
14c
6
14d
6
15a
2
15b
4
15c
4
17a
4
17b
1.03 0.04***b
0.83 0.03***b
0.70 0.02***b
0.63 0.022
1.2 0.08***b
0.6 0.08*b
1.6 0.07***b
0.72 0.03
4
17c
4
17d
6
Celecoxib
Ibuprofena
2
2.25 0.13
8
10
Values represent mean SEM of five animals for each group
Statistical analysis using one-way ANOVA
Significance levels * p \ 0.5, ** p \ 0.01, and *** p \ 0.001 as compared with the respective celecoxib
a
Data quoted from the literature(Hassan et al., 2014)
b
Mean significant difference with ibuprofen at p \ 0.001
the designed derivatives greatly supported our main
objective to avoid gastric injuries caused by COX-1 inhi-
bition (Table 2).
pyridines (15a–d, 16a–d, and 17a–d) showed wide range
of AI activity, and (iii) all compounds that possess anti-
inflammatory activity were less ulcerogenic than ibuprofen
and showed ulceration effect comparable to that of cele-
coxib, and specially (iv) The pyrazole derivative 12b and
the pyrazoline derivative 14b were less ulcerogenic than
celecoxib.
Conclusion
Five groups of diarylheterocycles 12a–d, 14a–d, 15a–d,
16a–d, and 17a–d in which the two aryl rings are as fol-
lows: (i) vicinal (1,5-diaryl) and attached to a five-mem-
bered pyrazole ring (12a–d) and (ii) not vicinal (3,5-diaryl)
and attached to a five-membered pyrazoline ring (14a–
d) or (iii) not vicinal (3,5-diaryl) and attached to a six-
membered pyridine ring (15a–d, 16a–d and 17a–d) were
synthesized for comparative biological evaluation. Struc-
ture activity and biological studies showed that (i) all the
compounds were more selective COX-2 inhibitors than
aspirin and ibuprofen but were less selective than cele-
coxib, (ii) pyrazoles (12a–d) and pyrazolines (14a–
d) exhibited AI activity (ED50 = 328–519 and
428–509 lmol/kg po range respectively) that was greater
than that exhibited by the reference drug aspirin
(ED50 = 710 lmol/kg po) and of comparable potency to
that of ibuprofen (ED50 = 327 lmol/kg po), but less than
that of celecoxib (ED50 = 30.9 lmol/kg po), while the
Experimental protocols
Chemistry
Melting points were determined on a Thomas-Hoover
capillary apparatus and are uncorrected. Infrared (IR)
spectra were recorded as films on NaCl plates using a
Nicolet 550 Series II Magna FT-IR spectrometer. 1H NMR
and 13C NMR spectra were measured on a Bruker
400-MHz NMR Spectrophotometer, Faculty of Pharmacy,
Beni-Suef University, Egypt, in CDCl3 or DMSO-d6 with
TMS as the internal standard, where J (coupling constant)
values are estimated in Hertz (Hz). Mass spectra (MS) were
recorded on Hewlett Packard 5988 spectrometer. Microa-
nalyses were performed for C, H, and N were carried out
on Perkin-Elmer 2400 analyzer (Perkin-Elmer, Norwalk,
123

Med Chem Res
and 1,150 (SO2) cm-1; H NMR (DMSO-d6, 400 MHz) d
3.06 (s, 3H, SO2CH3), 6.28 (s, 1H, pyrazole H-4), 6.38 (s,
1H, furyl H-4), 7.04 (s, 1H, furyl H-3), 7.39 (s, 1H, furyl
H-5), 7.60 (m, 2 H, phenyl H-2, H-6), and 7.94 (d,
J = 2.8 Hz, 2 H, phenyl H-3, H-5); 13C NMR (DMSO-d6,
100 MHz) d 13.4 (CH3, methanesulfonyl carbon), 105.5
(CH, pyrazolyl C-4), 112.0 (CH, furyl C-3), 112.2 (CH,
aminosulfonylphenyl C-2, C-6), 112.3 (CH, furyl C-4),
112.5 (CH, aminosulfonylphenyl C3, C-5), 126.7 (C, CF3),
127.4 (CH, furyl C-5), 134.1 (C, pyrazolyl C-5), 136.5 (C,
aminosulfonylphenyl C-1), 141.7 (C, aminosulfonylphenyl
C-4), 145.2 (C, furyl C-2), and 154.3 (C, pyrazolyl C-3);
MS (m/z, relative abundance %): 356 (M?, 56.86). Anal.
Calcd. for C15H11F3N2O3S: C, 50.56; H, 3.11; N, 7.86;
Found: C, 50.31; H, 2.84; N, 7.53.
1
CT, USA) at the Micro analytical unit of Cairo University,
Egypt. All compounds were within 0.4 % of the theo-
retical values. Silica gel column chromatography was
performed using Merck silica gel 60 ASTM (70–230
mesh). 4,4,4-Trifluoro-1-furan-2-yl-butane-1,3-dione (10a)
(Martins et al., 2012); 4,4,4-trifluoro-1-thiophen-2-yl-
butane-1,3-dione (10b) (Asiri et al., 2011); (4-aminosul-
phonylphenyl) hydrazine hydrochloride (11a) (Abdellatif
et al., 2008c); (4-methylsulphonylphenyl) hydrazine hydro-
chloride (11b)(Abdellatif et al., 2008b); 4-(5-thiophen-2-
yl-3-trifluoromethyl-pyrazol-1-yl)-benzenesulfonamide (12c)
(Asiri et al., 2011); 1-furan-2-yl-3-pyridin-3-yl-propenone
(13a) (Hanfeld et al., 1989); 1-furan-2-yl-3-pyridin-4-yl-
propenone (13b) (Edwards et al., 1994); 3-pyridin-3-yl-1-
thiophen-2-yl-propenone (13c) [18, 19], 3-pyridin-4-yl-1-
thiophen-2-yl-propenone (13d) (Ozdemir et al., 2007); and
1-(3-furan-2-yl-5-pyridin-4-yl-4,5-dihydro-pyrazol-1-yl)-eth-
anone (14b) (Nepali et al., 2011)were prepared according to
the reported procedures.
1-(4-Methanesulfonylphenyl)-5-thiophen-2-yl-3-trifluoro-
methyl-1H-pyrazole (12d)
29 % Yield; pale brown
solid; mp 188–190 °C; IR (KBr disk) 3,076 (C–H aro-
matic); 1,324 and 1,151 (SO2) cm-1; 1H NMR (DMSO-d6,
400 MHz) d 3.16 (s, 3H, SO2CH3), 6.80 (s, 1H, pyrazole
H-4), 7.00 (s, 1H, furyl H-3), 7.04 (s, 1H, furyl H-4), 7.39
(dd, J = 5.2 Hz, J = 4.0 Hz, 1 H, furyl H-5), 7.63 (m, 2H,
phenyl H-2, H-6), and 7.99 (m, 2H, phenyl H-3, H-5); 13C
NMR (DMSO-d6, 100 MHz) d 19.0 (CH3, methanesulfonyl
carbon), 106.5 (CH, pyrazole C-4), 111.4 (CH, thienyl
C-3), 112.3 (CH, aminosulfonylphenyl C-2, C-6), 112.9
(CH, thienyl C-4), 125.4 (C, pyrazole C-5), 126.3 (C, CF3),
127.3 (CH, aminosulfonylphenyl C-3, C-5), 135.6 (C,
aminosulfonylphenyl C-1), 142.2 (C, thienyl C-2), 142.7
(C, aminosulfonylphenyl C-4), 144.7 (C, pyrazole C-3),
and 144.9 (CH, thienyl C-5); MS (m/z, relative abundance
%); 372 (M?, 100). Anal. Calcd. for C15H11F3N2O3S: C,
48.38; H, 2.98; N, 7.52; Found: C, 48.14; H, 2.81; N, 7.38.
General method for preparation of pyrazoles (12a, 12b,
and 12d) A solution of the dione (10a or 10b, 1 mmol)
and (4-amino/methanesulphonylphenyl) hydrazine hydro-
chloride (11a or 11b, 1 mmol) in ethanol (40 mL) was
heated under reflux with stirring for 10 h. After cooling to
room temperature, the reaction mixture was concentrated
in vacuo to yield a gummy product which was further
purified by silica gel column chromatography using ethyl
acetate/hexane (1:3, v/v) as eluent to give analytically pure
compounds 12a, 12b, and 12d. Physical and spectral data
are listed below.
4-(5-Furan-2-yl-3-trifluoromethylpyrazol-1-yl)-benzenesul-
fonamide (12a) 48 % Yield; pale yellow solid; mp
212–214 °C; IR (KBr disk) 3,331; 3,235 (NH2), 2,924 (C–
1
H aromatic), and 1,345 and 1,155 (SO2) cm-1; H NMR
General method for preparation of pyrazolines (14a, 14c,
and 14d) A solution of the respective chalcone(13a, 13c
or 13d, 1 mmol) and hydrazine hydrate 99 % (0.06 g,
1.2 mmol) in glacial acetic acid (20 mL) was heated under
reflux for 36 h. The reaction mixture was cooled and
poured into crushed ice (40 g). The solid obtained was
filtered and crystallized from ethanol to give pure com-
pounds 14a, 14c, and 14d. Physical and spectral data are
listed below.
(DMSO-d6, 400 MHz) d 6.48 (s, 1H, pyrazolyl H-4), 6.55
(s, 1H, furyl H-4), 7.22 (s, 1.8 Hz, 1H, furyl H-3,), 7.58 (s,
2H, NH2, D2O exchangeable), 7.64 (d, J = 8.7 Hz, 2H,
phenyl H-2, H-6), 7.67 (s, 1H, furyl H-5), and 7.96 (d,
J = 8.7 Hz, 2H, phenyl H-3, H-5); 13C NMR (DMSO-d6,
100 MHz) d 105.2 (CH, pyrazolyl C-4), 106.9 (CH, furyl
C-4), 112.8 (CH, furyl C-3), 113.8 (CH, aminosulfonyl-
phenyl C-2, C-6), 123.7 (C, CF3), 132.1 (C, pyrazolyl C-5),
134.8 (CH, aminosulfonylphenyl C-4), 145.6 (C, pyrazolyl
C-3), 148.5 (CH, furyl C-5), 151.3 (C, furyl C-2), 151.8 (C,
aminosulfonylphenyl C-1), and 156.9 (CH, aminosulfo-
nylphenyl C-3, C-5); MS (m/z, relative abundance %): 357
(M?, 100). Anal. Calcd. for C14H10F3N3O3S: C, 47.06; H,
2.82; N, 11.76; Found: C, 46.82; H, 2.63; N, 11.43.
1-(3-Furan-2-yl-5-pyridin-3-yl-4,5-dihydro-pyrazol-1-yl)-
ethanone (14a)
244–246 °C; IR (KBr disk) 3,013 (C–H aromatic), 1,637
(C=O), and 1,561 (C=N) cm-1 1H NMR (CDCl3,
67 % Yield; pale brown solid; mp
;
400 MHz) d 2.42 (s, 3H, CH3), 3.14 (dd, J = 17.6, 4.8 Hz,
1H, pyrazole H-4), 3.78 (dd, J = 17.6, 11.6 Hz, 1H, pyr-
azole H0-4), 5.61 (dd, J = 11.6, 4.8 Hz, 1H, pyrazole H-5),
6.55 (s, 1H, furyl H-4), 6.80 (s, 1H, furyl H-3), 7.55(s, 1H,
furyl H-5), 7.58–7.60 (m, 2H, pyridyl H-2, H-6), and
5-Furan-2-yl-1-(4-methanesulfonylphenyl)-3-trifluoromethyl-
1H-pyrazole (12b) 0.33 % Yield; pale yellow solid; mp
125–127 °C; IR (KBr disk) 2,922 (C–H aromatic); 1,321
123

Med Chem Res
8.55–8.58 (m, 2H, pyridyl H-4, H-5); 13C NMR (CDCl3,
100 MHz) d 21.9 (CH3, methyl of acetyl group), 41.7
(CH2, pyrazolyl C-4), 57.4 (CH, pyrazolyl C-5), 112.1
(CH, furyl C-3), 112.9 (CH, furyl C-4), 123.7 (CH, pyridyl
C-5), 133.4 (CH, pyridyl C-4), 136.9 (CH, pyridyl C-3),
144.9 (CH, pyridyl C-6), 145.5 (CH, pyridyl C-2), 146.5
(C, furyl C-2), 147.7 (CH, furyl C-5), 149.2 (C, pyrazolyl
C-3), and 168.9 (C, acetyl carbonyl carbon); MS (m/z,
relative abundance %): 255 (M?, 75.6 %). Anal. Calcd. for
C14H13N3O2: C, 65.87; H, 5.13; N, 16.46. Found: C, 65.58;
H, 5.22; N, 16.63.
General procedure for synthesis of aminocyanopyridine
derivatives (15a, 15b, 15c, and 15d) A mixture of the
respective chalcone (13a, 13b, 13c, or 13d, 1 mmol) and
malononitrile (0.066 g, 1 mmol) in the presence of ammo-
nium acetate (0.61 g, 8 mmol) was dissolved in ethanol
(30 mL) and heated under reflux for 20 h. The product that
formed after cooling was filtered and re-crystallized from
ethanol to give pure compounds 15a, 15b, 15c, and 15d.
Physical and spectral data are listed below.
2-Amino-6-furan-2-yl-[3,40]bipyridinyl-3-carbonitrile
(15a) 66 % Yield; pale yellow solid; mp 166–168 °C; IR
(KBr disk): 3,386, 3,320 (NH2), 3,148 (C–H aromatic.), and
;
2,194 (C:N 1,564 (C=C) cm-1 1H NMR (DMSO-d6,
1-(5-Pyridin-3-yl-3-thiophen-2-yl-4,5-dihydro-pyrazol-1-yl)-
ethanone (14c) 74 % Yield; light brown solid; mp
255–257 °C; IR (KBr disk) 3,066 (C–H aromatic), 1,642
400 MHz) d 6.78 (s, 1H, aminopyridine H-5), 6.91 (s, 2H,
NH2, D2O exchangeable), 6.94 (d, J = 2.8 Hz, 1H, pyridyl
H-6); 7.48 (d, J = 3.2 Hz, 1H, pyridyl H-5); 7.59 (dd,
J = 7.6 Hz, J = 5.6 Hz, 1H, furyl H-4), 8.04 (d,
J = 12 Hz, 1H, pyridyl H-4), 8.06 (d, J = 7.2 Hz, 1 H,
furyl H-3), 8.72 (d, J = 4.4 Hz, 1H, furyl H-5), and 8.81 (s,
1H, pyridine H-2); 13C NMR (CDCl3, 100 MHz) d 90.6 (C,
aminopyridine C-3), 113.4 (CH, aminopyridine C-5), 113.8
(CH, furyl C-3), 114.9 (C, furyl C-2), 116.4 (C, C:N),
124.2 (CH, pyridyl C-5), 128.2 (C, pyridyl C-3), 136.7 (CH,
pyridyl C-4), 137.1(C, aminopyridine C-4), 137.5 (CH,
pyridyl C-6), 146.1 (CH, furyl C-5, 148.9 (CH, furyl C-4),
150.7 (CH, pyridyl C-2), 151.4 (C, aminopyridine C-6), and
152.6 (C, aminopyridine C-2); EIMS (m/z, relative abun-
dance %), 262 [M1, 100]; Anal. Calcd. for C15H10N4O: C,
68.69; H, 3.84; N, 21.36. Found: C, 68.57; H, 3.62; N, 21.06.
1
(C=O), and 1,605 (C=N); H NMR (CDCl3, 400 MHz) d
2.40 (s, 3H, CH3), 3.15 (dd, J = 17.6, 4.8 Hz, 1H, pyrazole
H-4), 3.47 (dd, J = 17.6, 11.6 Hz, 1H, pyrazole H0-4), 5.62
(dd, J = 11.6, 4.8 Hz, 1H, pyrazole H-5), 6.81(s, 1H, thi-
enyl H-4), 7.09 (d, J = 10.8 Hz, 2H, pyridyl H-5, H-6),
7.55 (d, J = 5.6 Hz, 1H, thienyl H-3,), 7.64 (d,
J = 4.4 Hz, 1H, thienyl H-5), and 8.54 (d, J = 10.8 Hz,
2H, pyridyl H-2, H-4) cm-1 13C NMR (CDCl3, 100 MHz)
;
d 21.8 (CH3, methyl of acetyl group), 42.9 (CH2, pyrazolyl
C-4), 57.9 (CH, pyrazolyl C-5), 123.8 (CH, thienyl C-3),
127.7 (CH, thienyl C-4), 128.3 (CH, pyridyl C-5), 132.3
(CH, pyridyl C-4), 132.9 (CH, pyridyl C-3), 133.5 (CH,
pyridyl C-6), 146.9 (CH, pyridyl C-2), 147.6 (C, thienyl
C-2), 149.1 (CH, thienyl C-5),149.5 (C, pyrazolyl C-3),
and 168.9 (C, acetyl carbonyl carbon); MS (m/z, relative
abundance %): 271 [M1, 29.77]. Anal. Calcd. for
C14H13N3OS: C, 61.97; H, 4.83; N, 15.49. Found: C, 62.20;
H, 4.73; N, 15.22.
2-Amino-6-furan-2-yl-[4,40]bipyridinyl-3-carbonitrile
(15b) 48 % Yield; pale yellow solid; mp 145–147 °C;
IR (KBr disk): 3,443; 3,390 (NH2), 3,113 (C–H aromatic),
and 2,214 (C:N 1,515 (C=C) cm-1; 1H NMR (DMSO-d6,
400 MHz) d 6.78 (s, 1H, aminopyridine H-5), 6.95 (s, 2H,
NH2, D2O exchangeable), 7.18 (s, 1H, furyl H-4), 7.49 (s,
1H, furyl H-3), 7.64 (s, 2H, pyridyl H-2, H-6), 8.01(d, 1H,
furyl H-5), and 8.76 (s, 2H, pyridyl H-3, H-5); 13C NMR
(DMSO-d6, 100 MHz) d 90.6 (C, aminopyridine C-3),
113.4 (CH, aminopyridine C-5), 113.9 (CH, furyl C-3),
114.5 (C, furyl C-2), 116.3 (C, C:N, 123.5 (CH, pyridyl
C-2, C-6), 137.2 (CH, pyridyl C-3, C-5),145.4 (CH, pyridyl
C-4), 146.3 (CH, furyl C-5), 147.7 (CH, furyl C-4), 149.1
(C, aminopyridine C-4),150.5 (C, aminopyridine C-6), and
154.9 (C, aminopyridine C-2); EIMS (m/z, relative abun-
dance %), 262 [M1, 83.38]; Anal. Calcd. for C15H10N4O:
C, 68.69; H, 3.84; N, 21.36. Found: C, 68.63; H, 3.55; N,
21.36.
1-(5-Pyridin-4-yl-3-thiophen-2-yl-4,5-dihydro-pyrazol-1-yl)-
ethanone (14d)
212–214 °C; IR (KBr disk): 3,043 (C–H aromatic), 1,638
(C=O), and 1,595 (C=N) cm-1 1H NMR (CDCl3,
61 % Yield; light brown solid; mp
;
400 MHz) d 2.43 (s, 3H, CH3), 3.10 (dd, J = 17.6, 4.8 Hz,
1H, pyrazole H-4), 3.78 (dd, J = 17.6, 11.6 Hz, 1H, pyr-
azole H0-4), 5.57 (dd, J = 11.6, 4.8 Hz, 1H, pyrazole H-5),
6.87 (s, 1H, thienyl H-4), 7.09 (m, 2H, pyridyl H-2, H-6),
7.23 (s, 1H, thienyl H-3,), 7.47 (s, 1H, thienyl H-5), and
8.58 (m, 2H, pyridyl H-3, H-5); 13C NMR (CDCl3,
100 MHz) d 21.8 (CH3, methyl of acetyl group), 42.5
(CH2, pyrazolyl C-4),59.1 (CH, pyrazolyl C-5),119.9 (CH,
thienyl C-3),124.5 (CH, thienyl C-4), 127.7 (CH, thienyl
C-5), 127.8 (C, thienyl C-2), 149.4 (CH, pyrazolyl C-3),
150.1 (CH, pyridyl C-4), 150.3 (CH, pyridyl C-3, C-5),
150.4 (CH, pyridyl C-2, C-6), and 168.9 (C, acetyl car-
bonyl carbon); MS (m/z, relative abundance %): 271 [M1,
99.71]. Anal. Calcd. for C14H13N3OS: C, 61.97; H, 4.83; N,
15.49. Found: C, 61.65; H, 4.61; N, 15.28.
2-Amino-6-thiophen-2-yl-[3,40]bipyridinyl-3-carbonitrile
(15c) 45 % Yield; light yellow solid; mp; 187–189 °C;
IR (KBr disk): 3,414, 3,330 (NH2), 2,925 (C–H aromatic),
123

Med Chem Res
2,210 (C:N 1,576 (C=C) cm-1
;
1H NMR (DMSO-d6,
(s, 1H, hydroxpyridine H-5), 6.89 (s, 1H, pyridyl H-6), 7.61
(s, 1H, furyl H-4), 7.64 (m, 1H, pyridyl H-5), 8.03(m, 1H,
pyridyl H-3), 8.12 (d, J = 6.8 Hz, 1H, furyl H-3), 8.76 (s,
1H, furyl H-5), 8.88 (m, 1H, pyridyl H-2), and 12.87 (s,
1H, OH, D2O exchangeable); 13C NMR (DMSO-d6,
100 MHz) d: 90.5 (C, hydroxypyridine C-3), 113.8 (CH,
hydroxypyridine C-5), 115.5 (CH, furyl C-3), 116.2 (C,
C:N 116.8 (C, pyridyl C-3), 124.2 (CH, pyridyl C-5),
132.5 (C, furyl C-2), 136.3 (CH, pyridyl C-4), 140.2 (C,
hydroxypyridine C-6), 142.6 (C, hydroxypyridine C-2),
147.7 (CH, furyl C-4), 148.8 (CH, pyridyl C-2), 150.4 (CH,
furyl C-5), 151.6 (CH, pyridyl C-6), and 153.1 (C,
hydroxypyridine C-4); EIMS (m/z, relative abundance %),
263 [M1, 100], Anal. Calcd for C15H9N3O2: C, 68.44; H,
3.45; N, 15.96. Found: C, 68.22; H, 3.31; N, 15.66.
400 MHz) d 6.99 (s, 2H, NH2, D2O exchangeable), 7.27 (s,
1H, aminopyridine H-5), 7.56 (s, 1H, thienyl H-4), 7.58
(dd, J = 7.6 Hz, J = 5.2 Hz, 1H, thienyl H-3) 7.77 (d,
J = 5.6 Hz 1H, pyridyl H-6), 7.86 (d, J = 5.2 Hz, 1H,
thienyl H-5), 8.07 (d, J = 8.0 Hz, 1H, pyridyl H-5), 8.71(d,
J = 4.0 Hz, 1H, pyridyl H-4), and 8.82 (d, J = 4.0 Hz,
1H, pyridyl H-2); 13C NMR (DMSO-d6, 100 MHz) d: 90.6
(C, aminopyridine C-3), 116.2 (CH, aminopyridine C-5,
116.6 (C, C:N 118.2 (CH, pyridyl C-5), 124.0 (CH, thi-
enyl C-3), 128.9 (CH, pyridyl C-6), 130.0 (CH, thienyl
C-5), 130.4 (CH, thienyl C-4), 133.7 (C, thienyl C-2),
136.7 (C, pyridyl C-3), 142.3 (C, aminopyridine C-4),
147.3(CH, pyridyl C-6), 149.2 (CH, pyridyl C-2), 150.8 (C,
aminopyridine C-6), and 154.9 (C, aminopyridine C-2);
EIMS (m/z, relative abundance %), 278 [M1, 10.77]; Anal.
Calcd. for C15H10N4S: C, 64.73; H, 3.62; N, 20.13. Found:
C, 65.00; H, 3.82; N, 19.99.
60-Furan-2-yl-20-hydroxy-[4,40]bipyridinyl-30-carbonitrile
(16b) 36 % Yield; yellow solid; mp 168–170 °C; IR (KBr
disk): 3,416 (OH), 3,023 (C–H aromatic), and 2,220 (C:N
1,653 (C=O) cm-1; 1H NMR (DMSO-d6, 400 MHz) d 6.79
(s, 1H, hydroxpyridine H-5), 6.85 (s, 1H, furyl H-3), 7.68 (s,
3H, pyridyl H-2, H-6 and furyl H-4), 8.10 (s, 1H, furyl H-5),
8.79 (s, 2H, pyridyl H-3, H-5), and 12.93 (s, 1H, OH, D2O
exchangeable). 13C NMR (DMSO-d6, 100 MHz) d: 90.5(C,
hydroxypyridine C-3), 113.5 (CH, hydroxypyridine C-5),
113.9 (CH, furyl C-3), 114.4 (CH, furyl C-5), 116.6 (C, furyl
C-2), 116.7(C, C:N 123.7 (CH, pyridyl C-3, C-5), 137.2 (C,
pyridyl C-4), 143.9 (C, hydroxypyridine C-4), 146.3 (CH,
furyl C-4), 147.3 (C, hydroxypyridine C-6), 150.5 (CH,
pyridyl C-2, C-6), and 156.2 (C, hydroxypyridine C-2);
EIMS (m/z, relative abundance %), 263 [M1, 77.47], Anal.
Calcd. for C15H9N3O2: C, 68.44; H, 3.45; N, 15.96. Found:
C, 68.60; H, 3.56; N, 15.95.
2-Amino-6-thiophen-2-yl-[4,40]bipyridinyl-3-carbonitrile
(15d) 45 % Yield; pale yellow solid; mp 168–170 °C;
IR (KBr disk): 3,443 (NH2), 3,095 (C–H aromatic), 2,183
;
(C:N), and 1,593 (C=C) cm-1 1H NMR (DMSO-d6,
400 MHz) d ppm: 6.96 (d, J = 3.6 Hz, 1H, thienyl H-4),
7.21 (s, 2H, NH2, D2O exchangeable), 7.26 (dd,
J = 4.4 Hz, J = 4.4 Hz, 1H, thienyl H-3), 7.35 (s, 1H,
aminopyridine H-5), 7.64 (dd, J = 6.0 Hz, J = 5.6 Hz,
2H, pyridyl H-3, H-5), 7.76 (d, J = 4.8 Hz, 1H, thienyl
H-5), and 8.74 (dd, J = 5.6 Hz, J = 5.6, 2H, pyridyl H-2,
H-6); 13C NMR (DMSO-d6, 100 MHz) d 90.6 (C, amino-
pyridine C-3), 115.9 (C, C:N 116.5 (C, pyridyl C-4),
117.8 (CH, aminopyridine C-5), 123.6 (CH, thienyl C-4),
128.9 (CH, pyridyl C-3, C-5), 130.1 (CH, thienyl C-5),
130.5 (CH, thienyl C-3), 142.5 (C, thienyl C-2), 145.2 (C,
aminopyridine C-6), 147.8 (C, aminopyridine C-4), 150.5
(CH, pyridyl C-2, C-6), and 154.9 (C, aminopyridine C-2);
EIMS (m/z, relative abundance %), 278 [M1, 41.28]; Anal.
Calcd. for C15H10N4S: C, 64.73; H, 3.62; N, 20.13. Found:
C, 64.44; H, 3.51; N, 19.88.
2-Hydroxy-60-thiophen-2-yl-[3,40]bipyridinyl-30-carbonitrile
(16c) 55 % Yield; yellow solid; mp 149–151 °C; IR
(KBr disk) 3,430 (OH), 3,096 (C–H aromatic), and 2,216
(C:N 1,643 (C=O) cm-1
;
1H NMR (DMSO-d6,
400 MHz) d ppm; 7.09–7.16 (m, 2H, hydroxpyridine
H-5, thienyl H-4), 7.20 (s, 1H, pyridyl H-6), 7.46 (d,
J = 8.0 Hz, 1H, H-3), 7.89 (s, 1H, pyridyl H-5), 8.09 (d,
J = 6.0, 1 H thienyl H-5), 8.76-8.81 (m, 1 H, pyridyl
H-2); 8.89–8.93 (m, I H, pyridyl H-4), and (12.93 (s, 1H,
OH, D2O exchangeable). 13C NMR (DMSO-d6,
100 MHz) 90.5 (C, hydroxypyridine C-3), 116.6 (C,
C:N 118.6 (CH, hydroxypyridine C-5), 124.2 (CH,
pyridyl C-5), 128.3 (CH, thienyl C-3), 129.5 (CH, pyridyl
C-6), 130.2 (CH, thienyl C-5), 132.2 (C, thienyl C-2),
132.4 (CH, thienyl C-4), 136.5 (CH, pyridyl C-2), 141.6
(C, hydroxypyridine C-4), 148.8 (C, hydroxypyridine
C-6), 148.9 (CH, pyridyl C-4), 150.4 (C, pyridyl C-3),
and 153.4 (C, hydroxypyridine C-2); EIMS (m/z, relative
abundance %), 279 [M1, 100]. Anal. Calcd. for
General procedure for synthesis of 2-oxo-3-cyanopyridine
(16a, 16b, 16c, and 16d) A mixture of the respective
chalcone (13a, 13b, 13c or 13d, 1 mmol), ethylcyanoace-
tate (0.117 g, 1 mmol), and ammonium acetate (0.61 g,
8 mmol) in ethanol (30 mL) was heated under reflux for
18 h. The product that formed after cooling was filtered
and recrystallized from ethanol to give pure compounds
16a, 16b, 16c, and 16d. Physical and spectral data are
listed below.
60-Furan-2-yl-20-hydroxy-[3,40]bipyridinyl-30-carbonitrile
(16a) 55 % Yield; yellow solid; mp 176–178 °C; (KBr
disk): 3,435 (OH), 3,060 (C–H aromatic), and 2,214 (C:N
1,654 (C=O) cm-1; 1H NMR (DMSO-d6, 400 MHz) d 6.79
123

Med Chem Res
1
C15H9N3OS: C, 64.50; H, 3.25; N, 15.04. Found: C,
64.47; H, 3.50; N, 15.28.
(C=C) cm-1; H NMR (CDCl3, 400 MHz) d 4.20 (s, 3H,
OCH3), 7.18 (s, 1H, methoxypyridine H-5), 7.28 (s, 1H,
furyl H-4), 7.56–7.61 (m, 3H, pyridyl H-2, H-6, furyl H-3),
7.76 (s, 1H, furyl H-5), and 8.82 (m, 2H, pyridyl H-2, H-6);
13C NMR (CDCl3, 100 MHz) d 55.0 (CH3, OCH3), 92.4
(C, methoxypyridine C-3), 111.3 (CH, methoxypyridine
C-5), 114.8 (C, furyl C-2), 118.8 (C, C:N 122.6 (CH,
furyl C-3), 122.7(CH, pyridyl C-3, C-5), 127.5 (CH, furyl
C-5), 128.7 (C, pyridyl C-4), 130.6 (CH, furyl C-4), 150.0
(C, methoxypyridine C-4), 150.4 (C, methoxypyridine
C-6), 150.6 (CH, pyridyl C-2, C-6), and 165.6 (C,
methoxypyridine C-2); EIMS (m/z, relative abundance %),
277 [M1, 0.76]. Anal. Calcd. for C16H11N3O2: C, 69.31; H,
4.00; N, 15.15. Found: C, 69.12; H, 3.68; N, 14.96.
2-Hydroxy-60-thiophen-2-yl-[4,40]bipyridinyl-30-carboni-
trile (16d) 55 % Yield; yellow solid; mp149–151 °C; IR
(KBr disk) 3,431 (OH), 3,092 (Ar–CH), and 2,216 (C:N
1,675 (C=O) cm-1 1H NMR (DMSO-d6, 400 MHz) d
;
ppm; 7.26 (s, 2H, hydroxpyridine H-5, thienyl H-4), 7.69
(s, 2H, pyridyl H-2, H-6), 7.88 (s, 1H, thienyl H-3), 8.07 (s,
1H, thienyl H-5), 8.79 (s, 2H, pyridine-H-3, H-5), and
12.95 (s, 1H, OH, D2O exchangeable); 13C NMR (DMSO-
d6, 100 MHz) d 90.5 (C, hydroxypyridine C-3), 113.5 (CH,
hydroxypyridine C-5), 113.9 (CH, thienyl C-3), 114.4 (CH,
thienyl C-4), 116.6 (C, C:N 116.7 (C, pyridyl C-4), 123.6
(CH, pyridyl C-3, C-5), 143.9 (C, thienyl C-2), 146.3 (CH,
thienyl C-5), 147.3 (C, hydroxypyridine C-4), 148.7 (C,
hydroxypyridine C-6), 150.5 (CH, pyridyl C-2, C-6), and
153.2 (C, hydroxypyridine C-2); EIMS (m/z, relative
abundance %), 279 [M1, 100]. Anal. Calcd. for
C15H9N3OS: C, 64.50; H, 3.25; N, 15.04. Found: C, 64.28;
H, 2.98; N, 15.36.
20-Methoxy-60-thiophen-2-yl [3.40]bipyridinyl-30-carboni-
trile (17c) 66 % Yield; white solid; mp 152–154 °C; IR
(KBr disk): 3,030 (C–H aromatic), 2,223 (C:N), and
1,588 (C = C) cm-1; H NMR (CDCl3, 400 MHz) d 4.20
1
(s, 3H, OCH3), 7.17 (d, J = 4.0 Hz, 1 H, thienyl H-4); 7.20
(S, 1 H, methoxypyridine H-5), 7.28 (m, 1 H, pyridyl H-6),
7.52–7.57 (m, 1H, pyridyl H-5), 7.54 (dd, J = 5.2 Hz,
5.2 Hz, 1 H, thienyl H-4), 8.07 (d, J = 7.6 Hz, 1 H, thienyl
H-5); 8.79 (d, J = 5.2 Hz, 1 H, pyridyl H-4), and 8.88 (s,
1H, pyridyl H-2); 13C NMR (CDCl3, 100 MHz) d 54.9
(CH3, OCH3), 92.4 (C, methoxypyridine C-3), 111.5 (CH,
methoxypyridine C-5), 115.1 (C, C:N 123.7 (CH, thienyl
C-3), 127.5 (C, pyridyl C-3), 128.6 (CH, pyridyl C-5),
130.5 (C, thienyl C-2), 132.3 (CH, pyridyl C-4), 136.2
(CH, thienyl C-4), 142.4 (CH, pyridyl C-2), 148.5 (CH,
thienyl C-5), 150.6 (CH, pyridyl C-6), 152.7 (C,
methoxypyridine C-6), 153.8 (C, methoxypyridine C-4),
and 165.0 (C, methoxypyridine C-2); EIMS (m/z, relative
abundance %), 293 [M1, 100]. Anal. Calcd. for
C16H11N3OS: C, 65.51; H, 3.78; N, 14.32. Found: C, 65.80;
H, 3.99; N, 14.02.
General procedure for synthesis of 2-methoxy-3-cyano-
pyridine derivatives (17a, 17b, 17c and 17d) A mixture
of the respective chalcone (13a, 13b, 13c or 13d, 1 mmol),
malononitrile (0.066 g, 1 mmol) and sodium metal
(0.023 g, 1 mmol) in methanol (30 mL) was stirred for
24 h at room temperature. The separated product was fil-
tered and recrystallized from methanol to give pure com-
pounds 17a, 17b, 17c, and 17d. Physical and spectral data
are listed below.
60-Furan-2-yl-20-methoxy-[3.40]bipyridinyl-30-carbonitrile
(17a) 45 % Yield; white solid; mp 155–157 °C; IR (KBr
disk): 3,057 (C–H aromatic), 2,211 (C:N), and 1,591
1
(C=C) cm-1; H NMR (CDCl3, 400 MHz): d 4.17 (s, 3H,
OCH3), 6.62 (s, 1 H, methoxypyridine H-5), 7.28–7.32 (m,
1 H, pyridyl H-6), 7.44-7.48 (m, 1 H, pyridyl H-5), 7.51(s,
1 H, furyl H-4), 7.16-7.22 (m, 1 H, pyridyl H-4), 8.07 (s,
1H, furyl H-3), 8.78 (s, 1 H, furyl H-5), and 8.89 (m, 1 H,
pyridyl H-2); 13C NMR (CDCl3, 100 MHz) d 54.8 (CH3,
OCH3), 92.6 (C, methoxypyridine C-3), 111.1 (CH,
methoxypyridine C-5), 112.8 (CH, furyl C-3), 115.1 (C,
C:N 123.7 (C, pyridyl C-3), 130.6 (CH, pyridyl C-5),
132.3 (C, furyl C-2), 136.1 (CH, pyridyl C-4), 145.2 (CH,
furyl C-4), 148.6 (CH, pyridyl C-2), 149.9 (CH, furyl C-5),
150.7 (CH, pyridyl C-6), 152.3 (C, methoxypyridine C-6),
152.9 (C, methoxypyridine C-4), and 165.2 (C, methoxy-
pyridine C-2); EIMS (m/z, relative abundance %), 277
[M1, 100]. Anal. Calcd. for C16H11N3O2: C, 69.31; H,
4.00; N, 15.15. Found: C, 69.52; H, 4.20; N, 15.13.
20-Methoxy-60-thiophen-2-yl [4.40]bipyridinyl-30-carboni-
trile (17d) 42 % Yield; white solid; mp182–184 °C; IR
(KBr disk) 3,073 (C–H aromatic), 2,220 (C:N 1), and 584
1
(C=C) cm-1; H NMR (DMSO-d6, 400 MHz) d 4.11 (s,
3H, OCH3), 7.25 (s, 1H, thienyl H-4), 7.72–7.78 (m, 2H,
methoxypyridine H-5, thienyl H-3), 7.86 (d, 2H, pyridine
H-2, H-6, J = 5.6 Hz), 8.13 (dd, 1H, thienyl H-4,
J = 8 Hz, 5.2 Hz), and 8.81–8.84 (m, 2H, pyridyl H-3,
H-5); 13C NMR (CDCl3, 100 MHz) d 54.9 (CH3, OCH3),
92.4 (C, methoxypyridine C-3), 111.5 (CH, methoxypyri-
dine C-5), 115.1 (C, C:N 123.6 (CH, thienyl C-3), 127.5
(CH, pyridyl C-3, C-5), 128.6 (CH, thienyl C-5), 130.4
(CH, thienyl C-4), 132.1 (C, pyridyl C-4), 142.9 (C, thienyl
C-2), 151.1 (CH, pyridyl C-2, C-6), 153.0 (C, methoxy-
pyridine C-4), 153.7 (C, methoxypyridine C-6), and 165.0
(C, methoxypyridine C-2); EIMS (m/z, relative abundance
%) 293 [M1, 100]. Anal. Calcd. for C16H11N3OS: C,
60-Furan-2-yl-20-methoxy-[4.40]bipyridinyl-30-carbonitrile
(17b) 45 % Yield; white solid; mp 177–179 °C; IR (KBr
disk): 2,925 (C–H aromatic), 2,217 (C:N), and 1,580
123

Med Chem Res
65.51; H, 3.78; N, 14.32. Found: C, 65.50; H, 3.64; N,
14.13.
magnifying lens (109) for the presence of lesions in the
form of hemorrhages or linear breaks and erosions. The
ulcer index was calculated and the degree of ulcerogenic
effect was expressed in terms of: (i) percentage incidence
of ulcer divided by 10, (ii) average number of ulcers per
stomach, and (iii) average severity of ulcers. The ulcer
index is the value that resulted from the sum of the above
three values.
Anti-inflammatory activity
In vitro cyclooxygenase (COX) inhibition assay
The ability of the test compounds listed in Table 1 to
inhibit ovine COX-1 and COX-2 (IC50 value, lM) was
determined using an enzyme immuno assay (EIA) kit
(Cayman Chemical, Ann Arbor, MI, USA) according to a
previously reported methods (Abdelazeem et al., 2014;
Roschek et al., 2009).
Conflict of interest The authors have declared no conflict of
interest.
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