An efficient one-pot synthesis of N-(1,3-diphenyl-1H-pyrazol-5-yl)amides

Article abstract of DOI:10.1002/jhet.343

(Chemical Equation Presented) A "one-pot" method for the synthesis of N-(1,3-diphenyl-1H-pyrazol-5-yl)amides was developed by cyclization of benzoylacetonitrile (1) and phenylhydrazine in neat condition followed by acylation. The corresponding N-(1,3-diph

Full text of DOI:10.1002/jhet.343

July 2010
An Efficient One-Pot Synthesis of N-(1,3-Diphenyl-1H-Pyrazol-
5-yl)amides
831
Wei-Nien Su,a Tsung-Ping Lin,a Kaung-Min Cheng,a Kuan-Chin Sung,b
Shao-Kai Lin,c and Fung Fuh Wonga*
aGraduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung,
Taiwan 40402, Republic of China
bDepartment of Surgery, Attending Physician Neurosurgery, Liouying Township, Taiwan 709,
Republic of China
cSustainable Environment Research Center, National Cheng Kung University, Tainan City, Taiwan
709, Republic of China
*E-mail: ffwong@mail.cmu.edu.tw
Received September 24, 2008
DOI 10.1002/jhet.343
Published online 4 June 2010 in Wiley InterScience (www.interscience.wiley.com).
A ‘‘one-pot’’ method for the synthesis of N-(1,3-diphenyl-1H-pyrazol-5-yl)amides was developed by
cyclization of benzoylacetonitrile (1) and phenylhydrazine in neat condition followed by acylation. The
corresponding N-(1,3-diphenyl-1H-pyrazol-5-yl)amides were provided in good to excellent yields (70–
90%). The significant advantages of the new synthetic method are excellent yields and simple work-up
procedure without isolation and purification of intermediary 5-amino-1,3-diphenyl pyrazol (2).
J. Heterocyclic Chem., 47, 831 (2010).
INTRODUCTION
RESULTS AND DISCUSSION
Pyrazole compounds have aroused great interest in
recent years because of their wide spectrum of biologi-
cal activities, including anti-inflammatory, antipyretic,
gastric secretion stimulatory, antidepressant, antibacte-
rial, anticonvulsant, antifilarial agents, and as analytical
reagents [1–4].
The traditional method for the synthesis of analog 2
[12,13] was the reaction of benzoylacetonitrile (1) with
phenylhydrazine under different conditions to provide
the key intermediate 5-amino-1,3-diphenyl pyrazole (2).
The conditions include: (1) heated in EtOH [14], (2)
microwave radiation [15], and (3) heated in acetic acid
(Scheme 1) [15]. Compound 2 was then subjected to
acylation to provide model compound 5 [N-(1,3-di-
phenyl-1H-pyrazol-5-yl)benzamide]. These methods all
involve two steps, and it is necessary to purify amino-
pyrazole 2. To develop a better synthetic methodology
for expanding the structural variation of compound 5,
we developed an efficient and convenient ‘‘one-pot’’
method for their syntheses. Benzoylacetonitrile (1) was
allowed to react with neat phenylhydrazine. The result-
ant 2, needless to be purified, was subjected to acylation
to generate model compound 5 in good to excellent
yields (Scheme 1).
A
recently reported pyrazole, 3-cyano-N-(1,3-di-
phenyl-1H-pyrazol-5-yl)benzamide (16, CDPPB), was
developed as the first centrally active positive alloste-
ric modulator of rat and human metabotropic gluta-
mate receptor mGluR5 subtype [5–7]. The receptors
play an important role in controlling neuronal excit-
ability and synaptic transmission in the central nerv-
ous system of the mammalian brain [8,9]. N-(1,3-di-
phenyl-1H-pyrazol-5-yl)amide derivatives are also con-
sidered as potential targets for therapeutic intervention
in a variety of neurological and psychiatric illnesses
[10]. The detailed structure–activity relationship stud-
ies of CDPPB analogs were reported by de Paulis et
al. in 2006 [11]. Herein, we provided an efficient and
convenient one-pot method to synthesize N-(1,3-di-
phenyl-1H-pyrazol-5-yl)amides for the large-scale
preparation.
We first tried to prepare 5-amino-1,3-diphenyl pyraz-
ole (2) by traditional methods to study their feasibility
for one-pot reaction of N-(1,3-diphenyl-1H-pyrazol-5-
yl)benzamide derivatives. The first method was refluxing
benzoylacetonitrile (1) with the same equivalent of
C
V
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W.-N. Su, T.-P. Lin, K.-M. Cheng, K.-C. Sung, S.-K. Lin, and F. F. Wong
Vol 47
added to the reaction mixture at 0–10ꢀC. The reaction
was stirred for 3–4 h from 0–10ꢀC to the room tempera-
ture under N2, and the corresponding acylation products
N-(1,3-diphenyl-1H-pyrazol-5-yl)amide 3–5 were suc-
cessfully provided in 78–90% yields in the one-pot reac-
tion (see Table 1).
Scheme 1
We then tried to apply this new method to synthesize
N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide derivatives
by use of different monosubstituted benzoyl halides con-
taining Cl, F, CH3, CF3, OMe, CN, and NO2 functional-
ities as the acylation agents (Scheme 2 and Table 2).
The
corresponding
N-(1,3-diphenyl-1-H-pyrazol-5-
phenylhydrazine in EtOH for >8.0 h (see Scheme 1,
path a) [14]. Compound 2 was generated in only 41%
yield via tandem condensation and thermal cyclization.
Another method was the use of microwave irradiation of
1 with hydrazine in EtOH solution for >4.0 h to provide
compound 2 in 58% yield (see Scheme 1, path b) [15].
The two literature-reported methods did not provide
compound 2 in satisfactory yield, as a result, not suita-
ble for direct acylation for a one-pot preparation. Use of
acetic acid as the solvent could provide 2 in 75–85%
yield (see Scheme 1, path c). However, the residual ace-
tic acid should be distilled before acylation. Those
methods were troublesome for removing EtOH or acetic
acid, especially in large-scale preparation.
yl)benzamide 6–19, which were reported as a novel
class of positive allosteric modulation of mGluR5 [5,11],
could be obtained in 70–90% yields (Table 2). Use of
2,4-difluorobenzoyl chloride also provided the corre-
sponding product 15 in 88% yields. Compounds 6–19
were fully characterized by spectroscopic methods, and
the data were consistent with reported [5,11]. For exam-
ple, the pyrazole ring in compound 16 presented a peak
at d 6.79 ppm for NHAC¼¼CA1H and a peak at d 95.7
ppm for NHA13C¼¼C in NMR. Its IR spectrum showed
absorption at 2232 cmꢁ1 for ACN stretching and 3308
cmꢁ1 for ANAH stretching [14]. Being the first cen-
trally active positive allosteric modulator of mGluR5,
compound 16 was synthesized by this one-pot method
in 73% yield.
We then carried out the reaction in neat condition.
Benzoylacetonitrile (1) was allowed to react with phe-
nylhydrazine in neat condition at reflux for 2.0 h (see
Scheme 1, path d). The desired 5-amino-pyrazole 2 was
successfully generated in 94% yield. Compound 2 was
fully characterized by spectroscopic method, and the
results were consistent with the reported data of previ-
ous literature [14,15]. This method is able to promote
the cyclization yield and provide the one-pot approach
for N-(1,3-diphenyl-1H-pyrazol-5-yl)amide derivatives.
For searching a better acylation agent to generate 3,
compound 2 was treated with various acylation agents,
including acetyl chloride, acetic anhydride, and ethyl ac-
etate (EtOAc) at room temperature or at reflux for 3.0–
4.0 h in THF (see Table 1). The corresponding acylated
products were obtained in 85%, 83%, and trace yields,
respectively. When compound 2 was reacted with ethyl
benzoate or ethyl phenylacetate, the reaction gave the
corresponding compounds 4 and 5 in 89% and 93%
yields (see Table 1).
The method can also be applied to the synthesis of
quinoline-8-sulfonyl and heteroarylaminopyrazoles. Use
of quinoline-8-sulfonyl chloride, 2-benzofurancarbonyl
chloride, 2-furoyl chloride, isoxazole-5-carbonyl chlo-
ride, 2-thiophenecarbonyl chloride, and trimellitic anhy-
dride chloride could successfully provide the corre-
sponding N-(1,3-diphenyl-1H-pyrazol-5yl)amide 20–25
in 70–90% yields (see Scheme 3 and Table 3).
In conclusion, we have successfully developed a
newly one-pot method by treating benzoylacetonitrile
(1) and phenylhydrazine with various acylation agents,
Table 1
The results of N-(1,3-diphenyl-1H-pyrazol-5-yl)amide derivatives
3–5 via step-by-step and one-pot synthesis.
N-(1,3-Diphenyl-1
H-pyrazol-5-yl)amides
Acylation agents
Yields (%)
Acetyl chloride
Acetic anhydride
Ethyl acetate
3
3
3
4
5
4
5
85a, 78b
83a
We then tried to combine the two-step process into a
one-pot reaction. Compound 1 was refluxed with the
same equivalent amount of phenylhydrazine in neat con-
dition for 2 h. After the reaction was completed, the re-
sultant compound 2 was dissolved in CH2Cl2 and stirred
in ice-bath. The acylation agents, including acetyl chlo-
ride, benzoyl chloride, and phenylacetyl chloride, were
diluted with anhydrous CH2Cl2, and THF was slowly
Tracea
89a
Ethyl benzoate
Ethyl phenylacetate
Phenylacetylchloride
Benzoyl chloride
93a
90b
78b
a The step-by-step synthesis.
b The one-pot synthesis reaction.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

July 2010
An Efficient One-Pot Synthesis of N-(1,3-Diphenyl-1H-pyrazol-5-yl)amides
833
purchased from TCI Chemical (Japan). Isoxazole-5-carbonyl
chloride 2-nitrobenzoyl chloride, 4-(trifluoromethyl)benzoyl
chloride, and trimellitic anhydride chloride were purchased
from Alfa Chemical. 2-Furoyl chloride was purchased from
Merck Chemical (Germany). Purification by gravity column
chromatography was carried out by use of Merck Reagents
Silica Gel 60 (particle size 0.063–0.200 mm, 70–230 mesh
ASTM). Infrared (IR) spectra were measured on a Bomem
Michelson Series FT-IR spectrometer. The wavenumbers
reported are referenced to the polystyrene 1601 cmꢁ1 absorp-
tion. Absorption intensities are recorded by the following
abbreviations: s, strong; m, medium; w, weak. Proton NMR
spectra were obtained on a Bruker (200 MHz) spectrometer by
use of CDCl3 and d6-DMSO as solvent. Carbon-13 NMR spec-
tra were obtained on a Bruker (50 MHz) spectrometer by the
use of CDCl3 as solvent. Carbon-13 chemical shifts are refer-
enced to the center of the CDCl3 triplet (d 77.0 ppm). Multi-
plicities are recorded by the following abbreviations: s, singlet;
d, doublet; t, triplet; q, quartet; m, multiplet; J, coupling con-
stant (Hz). Elemental analyses were carried out on a Heraeus
CHN–O RAPID element analyzer.
Standard procedure for condensation–cyclization to pre-
pare 5-amino-1,3-diphenyl pyrazole (2). [15] Benzoylaceto-
nitrile (1, 5.08 g, 35.1 mmol, 1.0 equiv) and phenylhydrazine
(3.80 g, 35.1 mmol, 1.0 equiv) were mixed and heated at
reflux for 2.0 h. The mixture was purified by column chroma-
tography on silica gel (CH2Cl2 as eluant) to give pure 5-
amino-1,3-diphenyl pyrazole (2, 7.81 g, 33.3 mmol) as yellow
solids in 94% yield: mp 129–131ꢀC (lit. [15] mp 129–130ꢀC);
1H-NMR (CDCl3, 200 MHz) d 3.82 (s, 2 H, NH2), 5.88 (s, 1
H, Py-H), 7.32–7.49 (m, 6 H, ArH), 7.58 (dd, 2 H, J ¼ 6.6,
1.2 Hz, ArH), 7.80 (dd, 2 H, J ¼ 6.6, 1.2 Hz, ArH); 13C-NMR
(50 MHz, CDCl3) d 88.1, 124.2, 125.6, 127.5, 127.8, 128.5,
129.5, 133.5, 138.7, 145.8, 151.5; IR (KBr) 3427 (brs, NH),
3337 (brs, NH), 3059, 1616, 1598, 1558, 1505, 1456, 1375,
1070, 952, 758, 698 cmꢁ1; MS m/z (relative intensity) 235
(Mþ, 100), 207 (20), 192 (3), 180 (3), 131 (7), 117 (4), 104
(11), 102(10), 92 (7), 77 (17), 65 (3), 51 (8); Anal. Calcd. for
C15H13N3: C, 76.57; H, 5.57; N, 17.86. Found: C, 76.21; H,
5.79; N, 18.03.
Scheme 2
including acetyl chloride, aryl chloride, heteroaryl
chloride, quinoline-8-sulfonyl chloride, and trimellic
anhydride chloride to give N-(1,3-diphenyl-1H-pyrazol-
5-yl)amides 3–25 in 70–90% yields. The new strategy
has been demonstrated to substantially promote the pro-
ductive yields in the generation of substituted N-(1,3-di-
phenyl-1-H-pyrazol-5-yl)benzamides 6–19 compounds.
EXPERIMENTAL
General procedure. All chemicals were reagent grade and
used as purchased. All reactions were carried out under nitro-
gen atmosphere and monitored by TLC analysis. Flash column
chromatography was carried out on silica gel (230–400 mesh).
Commercially available reagents were used without further pu-
rification unless otherwise noted. Dichloromethane, ethyl ace-
tate, hexanes, and methanol were purchased from ECHO
Chemical (USA). Dry tetrahydrofuran (reagent grade) and 3-
fluorobenzoyl chloride were purchased from Aldrich (USA).
The following compounds were purchased from Acoros Chem-
ical (Japan): acetyl chloride, benzoyl chloride, 3-cyanobenzoic
acid, 2,4-difluorobenzoyl chloride, 4-fluorobenzoyl chloride, 3-
methylbenzoyl chloride, and 4-methylbenzoyl chloride. Ben-
zoylacetonitrile, 2-chlorobenzoyl chloride, 3-chlorobenzoyl
chloride, 4-cyanobenzoyl chloride, 3-methoxylbenzoyl chlo-
ride, phenylhydrazine, and quinoline-8-sulfonyl chloride were
Table 2
The results of the one-pot synthesis of N-(1,3-diphenyl-1H-pyrazol-5-
yl)benzamide derivative.
Standard procedure for one-pot synthesis of N-(1,3-di-
phenyl-1H-pyrazol-5yl)amide derivatives (3–25). [4,8–10]
Benzoylacetonitrile (1, 501 mg, 3.45 mmol, 1.0 equiv) and
phenylhydrazine (374 mg, 3.46 mmol, 1.0 equiv) were mixed
and stirred at reflux for 2.0–3.0 h. After the reaction was com-
pleted, the resultant compound 2 was dissolved in CH2Cl2 (10
mL) and stirred in ice-bath. Acetyl chloride, benzoxyl chloride,
benzyl chloride, or heteroaryl chloride (4.14 mmol, 1.2 equiv)
Products
Acid chloride
N-(1,3-Diphenyl-
1H-pyrazol-5-yl)
benzamides
R1
R2
R3
Yields (%)
H
H
H
5
6
7
8
9
10
11
12
13
14
78
77
70
85
71
84
76
78
90
72
88
73
78
76
89
H
H
F
H
H
F
Scheme 3
Cl
H
H
Cl
H
H
H
Me
H
H
H
H
H
Me
CF3
H
OMe
H
H
OMe
H
H
F
H
F
H
15
16 (CDPPB)
CN
H
H
CN
H
NO2
17
18
19
NO2
H
H
H
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

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W.-N. Su, T.-P. Lin, K.-M. Cheng, K.-C. Sung, S.-K. Lin, and F. F. Wong
Vol 47
Table 3
206 (2), 105 (100), 77 (45), 51 (5); Anal. Calcd. for
C22H17N3O: C, 77.86; H, 5.05; N, 12.38. Found: C, 77.56; H,
5.24; N, 12.47.
The results of the one-pot synthesis of N-(1,3-diphenyl-1H-pyrazol-5-
yl)amide derivatives.
3-Fluoro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
(6). [12] mp (recrystallized from CH2Cl2/MeOH) 175–177ꢀC;
1H-NMR (CDCl3, 200 MHz) d 7.18 (s, 1 H, Py-H), 7.31–7.41
(m, 8 H, ArH), 7.57 (dd, 4 H, J ¼ 4.2, 1.4 Hz, ArH), 7.88 (dd,
2 H, J ¼ 6.6, 1.4 Hz, ArH), 8.21 (b, 1 H, NH); 13C-NMR (50
MHz, CDCl3) d 96.4, 114.5, 114.9, 119.4, 119.8, 122.4 (2 ꢂ
CH), 124.7 (2 ꢂ CH), 125.8, 128.6, 128.7 (2 ꢂ CH), 130.1 (2
ꢂ CH), 130.6, 130.8, 132.9, 135.3, 135.4, 136.3,137.8, 152.0,
160.4, 162.6, 165.3; IR (KBr) 3269 (brs, NH), 3064, 1684,
1589, 1458, 1365, 1290, 1072, 956, 692 cmꢁ1; MS m/z (rela-
tive intensity) 357 (Mþ, 15), 356 (15), 206 (2), 123 (100), 101
(18), 95 (35), 77 (17), 51 (10); Anal. Calcd. for C22H16FN3O:
C, 73.94; H, 4.51; N, 11.76. Found: C, 73.66; H, 4.46; N,
11.41.
4-Fluoro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
(7). [14] mp (recrystallized from CH2Cl2/MeOH) 187–189ꢀC;
1H-NMR (CDCl3, 200 MHz) d 7.12 (t, 1 H, J ¼ 8.7 Hz, ArH),
7.18 (s, 1 H, Py-H), 7.32–7.48 (m, 4 H, ArH), 7.55–7.58 (m, 4 H,
ArH), 7.70–7.77 (m, 2H, ArH), 7.88 (dd, 4 H, J ¼ 7.9, 1.3 Hz,
ArH), 8.12 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 96.0,
116.0, 116.4, 124.8 (2 ꢂ CH), 125.8 (2 ꢂ CH), 128.2, 128.6 (2 ꢂ
CH), 128.7, 129.4, 129.6, 130.1 (2 ꢂ CH), 132.9, 136.5, 137.9,
146.2, 152.1, 162.6; IR (KBr) 3217 (brs, NH), 3045, 1685, 1529,
1504, 1460, 1367, 1286, 1234, 1072, 918, 760, 694 cmꢁ1; MS m/
z (relative intensity) 357 (Mþ, 15), 234 (1), 206 (1), 123 (100),
102 (24), 95 (46), 77 (24), 51 (12); Anal. Calcd. for
C22H16FN3O: C, 73.94; H, 4.51; N, 11.76. Found: C, 73.75; H,
4.61; N, 11.43.
N-(1,3-Diphenyl-1H- Yields
Acylation agents
pyrazol-5-yl)amides
(%)
2-Furoyl chloride
20
21
22
23
24
25
70
77
71
73
84
90
2-Thiophenecarbonyl chloride
Isoxazole-5-carbonyl chloride
2-Benzofurancarbonyl chloride
Trimellitic anhydride chloride
Quinoline-8-sulfonyl chloride
in 10 mL of CH2Cl2 or THF were slowly added to the reaction
mixture at 0ꢀC under N2, respectively. The reaction was stirred
at 0–10ꢀC for 3–4 h. The reaction mixture was washed with
water (10 mL) and saturated aqueous NaHCO3 (10 mL ꢂ 2).
The organic layer was dried over MgSO4, filtered, and concen-
trated under reduced pressure. The residue was purified by col-
umn chromatography on silica gel or recrystallization to give
the corresponding acylation product N-(1,3-diphenyl-1H-pyra-
zol-5yl)amide 3–25 in 70–90% yields.
N-(1,3-Diphenyl-1H-pyrazol-5-yl)acetamide (3). mp (puri-
1
fied by column chromatography on silica gel) 148–150ꢀC; H-
NMR (CDCl3, 200 MHz) d 2.06 (s, 3 H, Me), 6.95 (s, 1 H,
Py-H), 7.32–7.84 (m, 8 H, ArH), 7.81 (dd, 2 H, J ¼ 6.6, 1.7
Hz, ArH), 10.89 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d
23.7, 96.4, 124.2, 125.0, 125.7 (2 ꢂ CH), 128.1 (2 ꢂ CH),
128.6 (2 ꢂ CH), 129.8 (2 ꢂ CH), 133.0, 136.5, 137.9, 151.8,
167.0; IR (KBr) 3230 (brs, NH), 3061, 1681, 1595, 1560,
1505, 1496, 1468, 1367, 1267, 1072, 954, 763, 692 cmꢁ1; MS
m/z (relative intensity) 277 (Mþ, 14), 235 (24), 207 (6), 180
(2), 131 (5), 102 (23), 77 (45), 65 (5), 51 (34), 43 (100); Anal.
Calcd. for C17H15N3O: C, 73.63; H, 5.45; N, 15.15. Found: C,
73.52; H, 5.64; N, 15.49.
2-Phenyl-N-(1,3-diphenyl-1H-pyrazol-5-yl)acetamide
(4). mp (purified by column chromatography on silica gel)
132–134ꢀC; 1H-NMR (CDCl3, 200 MHz) d 3.69 (s, 2 H,
CH2), 7.05 (s, 1 H, Py-H), 7.09–7.43 (m, 13 H, ArH), 7.83 (d,
2 H, J ¼ 6.6 Hz, ArH), 9.83 (b, 1 H, NH); 13C-NMR (50
MHz, CDCl3) d 29.7, 94.9, 123.66 (2 ꢂ CH), 124.2, 125.7 (2
ꢂ CH), 128.1 (2 ꢂ CH), 128.6, 129.5 (4 ꢂ CH), 129.6, 129.8
(2 ꢂ CH), 132.9, 133.5, 136.5, 137.4, 151.8, 167.3; IR (KBr)
3268 (brs, NH), 3064, 2924, 1700, 1559, 1486, 1458, 1368,
1158, 1073, 954 cmꢁ1; MS m/z (relative intensity) 353 (Mþ,
8), 269 (1), 235 (18), 207 (3), 180 (1), 167 (1), 131 (3), 102
(17), 91 (100), 77 (40), 65 (29), 51 (18); Anal. Calcd. for
C23H19N3O: C, 78.16; H, 5.42; N, 11.89. Found: C, 78.01; H,
5.34; N, 11.69.
N-(1,3-Diphenyl-1H-pyrazol-5-yl)benzamide (5). [11] mp
(purified by column chromatography on silica gel) 171–173ꢀC;
1H-NMR (CDCl3, 200 MHz) d 7.20 (s, 1 H, Py-H), 7.30–7.64
(m, 9 H, ArH), 7.88 (dd, 2 H, J ¼ 6.6, 1.6 Hz, ArH), 7.87 (dd,
2 H, J ¼ 6.6, 1.6 Hz, ArH), 8.06 (dd, 2 H, J ¼ 6.6, 1.6 Hz,
ArH), 9.42 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 95.9,
124.9 (2 ꢂ CH), 125.8 (2 ꢂ CH), 127.1 (2 ꢂ CH), 128.2,
128.5 (2 ꢂ CH), 129.0 (2 ꢂ CH), 129.3, 130.1 (2 ꢂ CH),
130.2, 132.5, 133.0, 133.7, 136.7, 137.9, 171.1; IR (KBr) 3275
(brs, NH), 3062, 1645, 1558, 1365, 1258, 1072, 954, 763, 711,
698 cmꢁ1; MS m/z (relative intensity) 339 (Mþ, 74), 234 (2),
2-Chloro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (8). [14]
mp (purified by column chromatography on silica gel) 147–
149ꢀC; 1H-NMR (CDCl3, 200 MHz) d 7.14 (s, 1 H, Py-H),
7.22–7.68 (m, 11 H, ArH), 7.70–7.94 (m, 3 H, ArH), 8.64 (b,
1 H, NH); 13C-NMR (50 MHz, CDCl3) d 96.2, 125.5 (2 ꢂ
CH), 125.8 (2 ꢂ CH), 127.5, 128.2, 128.6 (2 ꢂ CH), 128.9,
129.5 (2 ꢂ CH), 130.5, 131.2, 132.0,132.5,132.9,136.6, 137.6,
151.9, 162.7, 168.9; IR (KBr) 3256 (brs, NH), 3066, 1666,
1566, 1502, 1460, 1369, 1263, 1117, 1051, 765, 696 cmꢁ1
;
MS m/z (relative intensity) 373 (Mþ, 10), 338 (18), 234 (1),
206 (2), 141 (44), 139 (100), 111 (36), 102 (34), 77 (36), 51
(16); Anal. Calcd. for C22H16ClN3O: C, 70.68; H, 4.31; N,
11.24. Found: C, 70.29; H, 4.51; N, 11.14.
3-Chloro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (9). [14]
mp (purified by column chromatography on silica gel) 168–
170ꢀC; 1H-NMR (CDCl3, 200 MHz) d 7.14 (s, 1 H, Py-H),
7.22–7.61 (m, 10 H, ArH), 7.65–7.94 (m, 3 H, ArH), 8.04 (b, 1
H, NH); 13C-NMR (50 MHz, CDCl3) d 96.4, 124.8 (2 ꢂ CH),
124.9, 125.8 (2 ꢂ CH), 127.7, 128.2, 128.6 (2 ꢂ CH), 128.8,
130.1 (2 ꢂ CH), 130.3, 132.6, 133.7, 134.9, 136.2, 137.8,
152.1, 162.6, 169.6; IR (KBr) 3248 (brs, NH), 3052, 1675,
1573, 1498, 1455, 1431, 1358, 1292, 1252, 1061, 758, 692
cmꢁ1; MS m/z (relative intensity) 373 (Mþ, 15), 343 (1), 234
(2), 206 (3), 141 (33), 139 (100), 111 (46), 102 (32), 77 (33),
75 (27), 51 (19). Anal. Calcd. for C22H16ClN3O: C, 70.68; H,
4.31; N, 11.24. Found: C, 70.41; H, 4.24; N, 11.48.
2-Methyl-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (10). mp
(recrystallized from CH2Cl2/hexane) 187–189ꢀC; 1H-NMR
(CDCl3, 200 MHz) d 2.17 (s, 3 H, CH3), 6.82 (s, 1 H, Py-H),
6.91–7.56 (m, 12 H, ArH), 7.86 (dd, 2 H, J ¼ 7.1, 1.0 Hz,
Journal of Heterocyclic Chemistry
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An Efficient One-Pot Synthesis of N-(1,3-Diphenyl-1H-pyrazol-5-yl)amides
835
ArH), 10.4 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 19.7,
102.8, 125.2, 125.7, 125.9, 127.3, 128.2, 128.6, 129.1, 129.4,
131.3 (5 ꢂ CH), 132.8, 134.3 (2 ꢂ C), 137.6, 138.3 (2 ꢂ C),
151.8, 172.1; IR (KBr) 3064 (brs, NH), 1718, 1683, 1599,
1549, 1501, 1458, 1383, 1319, 1233, 1140, 1108, 1078, 953,
901, 841 cmꢁ1; MS m/z (relative intensity) 354 (Mþ, 14), 336
(13), 307 (11), 289 (11), 262 (8), 235 (9), 219 (12), 178 (9),
154 (68), 136 (65), 119 (100), 107 (36), 91 (79), 77 (50), 69
(43), 55 (50); Anal. Calcd. for C23H19N3O: C, 78.16; H, 5.42;
N, 11.89. Found: C, 78.19; H, 5.47; N, 11.69.
CH), 129.6, 130.0 (2 ꢂ CH), 133.0, 134.6, 136.6, 137.9, 152.0,
160.1, 163.7; IR (KBr) 3257 (brs, NH), 3066, 2843, 1667, 1597,
1560, 1502, 1460, 1369, 1284, 1230, 1041, 769, 702 cmꢁ1; MS
m/z (relative intensity) 369 (Mþ, 1), 234 (2), 206 (2), 135 (100),
107 (27), 92 (25), 77 (52), 64 (13), 51 (12); Anal. Calcd. for
C23H19N3O: C, 74.78; H, 5.18; N, 11.37. Found: C, 74.56; H,
5.42; N, 11.61.
2,4-Difluoro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
1
(15). mp (recrystallized from CH2Cl2/hexane) 162–164ꢀC; H-
NMR (CDCl3, 200 MHz) d 6.74–6.89 (m, 1 H, ArH), 7.92–
7.10 (m, 1 H, ArH), 7.26 (s, 1 H, Py-H), 7.31–7.51 (m, 4 H,
ArH), 7.55–7.59 (m, 4 H, ArH), 7.88 (dd, 2 H, J ¼ 6.7, 1.4 Hz,
ArH), 8.14–8.39 (m, 1 H, ArH), 8.74 (b, 1 H, NH); 13C-NMR
(50 MHz, CDCl3) d 95.5, 104.0, 104.5, 105.0, 112.9, 113.3,
116.7, 116.9, 117.0, 125.1 (2 ꢂ CH), 125.8 (2 ꢂ CH), 128.2,
128.6 (2 ꢂ CH), 128.8, 130.0 (2 ꢂ CH), 132.9, 134.2, 134.4,
136.7, 152.0, 158.2, 164.3; IR (KBr) 3423 (brs, NH), 3061,
1693, 1614, 1570, 1494, 1289, 1111, 970, 766, 694 cmꢁ1; MS
m/z (relative intensity) 376 (Mþ, 100), 358 (3), 336 (3), 304
(3), 282 (5), 262 (3), 234 (6), 219 (4), 207 (5), 154 (5), 141
(98), 113 (7), 92 (4), 77 (12), 57 (4). Anal. Calcd. for
C22H15F2N3O: C, 70.39; H, 4.03; N, 11.19. Found: C, 70.64;
H, 4.23; N. 11.46.
4-Methyl-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (11). [11]
1
mp (recrystallized from CH2Cl2/hexane) 181–183ꢀC; H-NMR
(CDCl3, 200 MHz) d 2.39 (s, 3 H, CH3), 7.19 (s, 1 H, Py-H),
7.24–7.65 (m, 12 H, ArH), 7.89 (dd, 2 H, J ¼ 7.3, 1.4 Hz,
ArH), 8.12 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 21.5,
95.7, 124.8 (2 ꢂ CH), 125.8 (2 ꢂ CH), 127.1 (2 ꢂ CH),
128.1, 128.6 (2 ꢂ CH), 129.6, 129.7 (2 ꢂ CH), 130.0 (2 ꢂ
CH), 130.3, 133.0, 136.8, 137.9, 143.3, 152.0, 163.6; IR (KBr)
3277 (brs, NH), 1654, 1558, 1505, 1459, 1387, 1282, 1074,
1018, 953, 915, 834 cmꢁ1; MS m/z (relative intensity) 354
(Mþ, 6), 233 (2), 205 (2), 177 (1), 167 (1), 130 (3), 119 (100),
102 (19), 91 (56), 77 (19), 65 (8), 51 (5); Anal. Calcd. for
C23H19N3O: C, 78.16; H, 5.42; N, 11.89. Found: C, 78.05; H,
5.34; N, 11.71.
3-Trifluoromethyl-N-(1,3-diphenyl-1H-pyrazol-5-yl)benza-
mide (12). [11] mp (recrystallized from CH2Cl2/ hexane) 196–
198ꢀC; 1H-NMR (CDCl3, 200 MHz) d 7.19 (s, 1 H, Py-H),
7.29–7.49 (m, 4 H, ArH), 7.56–7.58 (m, 4 H, ArH), 7.71 (d, 2
H, J ¼ 8.7 Hz, ArH), 7.82–7.91 (m, 4 H, ArH), 8.21 (b, 1 H,
NH); 13C-NMR (50 MHz, CDCl3) d 96.4, 124.0, 124.7 (2 ꢂ
CH), 125.8 (2 ꢂ CH), 126.1, 127.6 (2 ꢂ CH), 128.3, 128.6 (2
ꢂ CH), 128.6, 128.8, 129.4, 130.1 (2 ꢂ CH), 130.5, 131.1,
133.8, 136.1, 1 137.8, 152.1, 162.6; IR (KBr) 3205 (brs, NH),
3051, 1658, 1593, 1556, 1537, 1498, 1460, 1367, 1303, 1168.
1066, 854, 758, 688 cmꢁ1; MS m/z (relative intensity) 407
(Mþ, 30), 377 (2), 234 (4), 206 (4), 173 (100), 145 (54), 131
(6), 102 (38), 77 (38), 51 (15); Anal. Calcd. for C23H16F3N3O:
C, 67.81; H, 3.96; N, 10.31. Found: C, 68.12; H, 4.10; N,
10.21.
3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
CDPPB). [11,14,15] mp (purified by column chromatography
(16,
1
on silica gel) 207–208ꢀC; H-NMR (CDCl3, 200 MHz) d 6.90
(s, 1 H, Py-H), 7.26–7.45 (m, 11 H, ArH), 7.79–7.92 (m, 3 H,
ArH), 8.86 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 100.5,
112.7, 117.1, 124.3 (2 ꢂ CH), 125.3 (2 ꢂ CH), 128.3 (2 ꢂ CH
þ CH), 128.7, 129.0, 129.5 (2 ꢂ CH), 129.6, 131.2, 131.8,
134.4, 135.3, 135.7, 138.6, 151.7, 164.3; IR (KBr) 3309 (brs,
NH), 3068, 2922, 2852, 2232 (s, CBN), 1689, 1654, 1560,
1498, 1458, 1363, 1292, 1190, 1072, 916 cmꢁ1; MS m/z (rela-
tive intensity) 364 (Mþ, 59), 234 (11), 207 (6), 147 (8), 130
(100), 102 (49), 91 (2), 77 (15), 64 (1), 51 (8); Anal. Calcd. for
C23H16N4O: C, 75.81; H, 4.43; N, 15.38. Found: C, 75.49; H,
4.65; N, 15.18.
4-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (17). [11]
mp (purified by column chromatography on silica gel) 207–
209ꢀC (lit. [11] mp 207–208ꢀC); 1H-NMR (CDCl3, 200 MHz) d
7.02 (s, 1 H, Py-H), 7.35–7.49 (m, 6 H, ArH), 7.66–7.72 (m, 3 H,
ArH), 7.90–7.95 (m, 3 H, ArH), 8.12–8.20 (m, 2 H, ArH), 8.27
(b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 99.7, 112.7, 117.7,
124.0 (2 ꢂ CH), 125.3 (2 ꢂ CH), 127.7, 127.9, 128.6 (2 ꢂ CH),
129.9 (2 ꢂ CH), 129.9, 131.3, 132.1, 133.4, 134.9, 135.3, 136.8,
139.2, 150.7, 163.8; IR (KBr) 3250 (brs, NH), 3087, 2308 (s,
C[tbond]N), 1686, 1578, 1501, 1296, 769, 699 cmꢁ1; MS m/z
(relative intensity) 364 (Mþ, 100), 335 (6), 262 (3), 234 (12),
206 (7), 130 (98), 102 (44), 77 (16), 51 (5); Anal. Calcd. for
C23H16N4O: C, 75.81; H, 4.43; N, 15.38. Found: C, 76.12; H,
4.42; N, 15.14.
2-Methoxy-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
(13). mp (purified by column chromatography on silica gel)
1
196–198ꢀC; H-NMR (CDCl3, 200 MHz) d 3.52 (s, 3 H, Me),
6.91 (d, 1 H, J ¼ 6.9 Hz, ArH), 7.10 (t, 1 H, J ¼ 6.4 Hz,
ArH), 7.13 (s, 1 H, Py-H), 7.33–7.89 (m, 8 H, ArH), 7.91 (dd,
2 H, J ¼ 6.7, 1.3 Hz, ArH), 8.43 (dd, 1 H, J ¼ 6.7, 1.3 Hz,
ArH); 13C-NMR (50 MHz, CDCl3) d 55.6, 94.6, 111.4, 120.1,
121.8, 125.8 (2 ꢂ CH), 125.9 (2 ꢂ CH), 128.0, 129.8 (2 ꢂ
CH), 132.7 (2 ꢂ CH), 133.1, 133.9, 135.1, 136.7, 138.1,
152.1, 157.2, 161.2; IR (KBr) 3306 (brs, NH), 3062, 2924,
1674, 1598, 1570, 1496, 1483, 1371, 1296, 1244, 1163. 1018,
759, 694 cmꢁ1; MS m/z (relative intensity) 369 (Mþ, 2), 206
(1), 135 (100), 120 (3), 102 (15), 92 (25), 77 (49), 63 (7), 51
(11); Anal. Calcd. for C23H19N3O: C, 74.78; H, 5.18; N,
11.37. Found: C, 74.98; H, 5.43; N, 11.48.
3-Methoxy-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
(14). [11] mp (purified by column chromatography on silica
gel) 175–177ꢀC (lit. [11] mp 177–179ꢀC); 1H-NMR (CDCl3,
200 MHz) d 3.84 (s, 3 H, CH3), 7.19 (s, 1 H, Py-H), 7.28–7.72
(m, 12 H, ArH), 7.88 (d, 2 H, J ¼ 8.0 Hz, ArH), 8.21 (b, 1 H,
NH); 13C-NMR (50 MHz, CDCl3) d 55.5, 96.1, 112.6, 118.6,
118.7, 124.4 (2 ꢂ CH), 124.8, 125.9 (2 ꢂ CH), 128.2, 128.6 (2 ꢂ
2-Nitro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (18). [11]
1
mp (recrystallized from CH2Cl2/hexane) 229–231ꢀC; H-NMR
(CDCl3, 200 MHz) d 7.00 (s, 1 H, Py-H), 7.36–7.89 (m, 12 H,
ArH), 8.08–8.26 (m, 3 H, ArH þ NH); 13C-NMR (50 MHz,
CDCl3) d 100.1, 124.4 (2 ꢂ CH), 124.8, 125.7 (2 ꢂ CH),
128.6, 129.2 (2 ꢂ CH), 129.7, 130.2 (2 ꢂ CH), 132.0, 133.1,
134.6, 135.6, 137.0, 138.9, 144.4, 147.0, 150.8, 167.8; IR
(KBr) 3261 (brs, NH), 3061, 1718, 1533, 1502, 1354, 1249,
757, 690 cmꢁ1; MS m/z (relative intensity) 385 (Mþ, 66), 370
(27), 339 (22), 323 (10), 307 (45), 289 (39), 285 (18), 262
Journal of Heterocyclic Chemistry
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Vol 47
(15), 234 (32), 206 (22), 178 (31), 165 (48), 154 (100); Anal.
Calcd. for C22H16N4O3: C, 68.74; H, 4.20; N, 14.58. Found:
C, 68.81; H, 4.15; N, 14.81.
164–166ꢀC; 1H-NMR (CDCl3) d 7.24–7.72 (m, 14 H, ArH),
7.90 (dd, 2 H, J ¼ 8.1, 1.6 Hz, ArH), 8.62 (b, 1 H, NH); 13C-
NMR (CDCl3) d 95.8, 111.9, 112.5, 123.0, 124.2, 124.7 (2 ꢂ
CH), 125.8 (2 ꢂ CH), 127.3, 127.5, 127.7 (2 ꢂ CH þ CH),
128.2, 128.6 (2 ꢂ CH), 130.1, 132.9, 135.8, 137.8, 147.2, 152.1,
154.8; IR (KBr) 3061 (brs, NH), 2922, 2850, 1554, 1504, 1365,
1282, 1170, 1142 cmꢁ1; MS m/z (relative intensity) 379 (Mþ,
47), 351 (16), 246 (4), 233 (2), 206 (3), 180 (1), 145 (100), 131
(4), 102 (15), 89 (33), 77 (14), 63 (5), 51 (4); HRMS Calcd. for
C24H17N3O2: 379.1321, Found 379.1318.
4-Nitro-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (19). [11]
mp (recrystallized from CH2Cl2/hexane) 221–223ꢀC (lit. [11]
1
mp 221–223ꢀC); H-NMR (CDCl3, 200 MHz) d 6.95 (s, 1 H,
Py-H), 7.21–7.89 (m, 9 H, ArH þ NH), 8.18 (d, 2 H, J ¼ 6.5
Hz, ArH), 8.34 (d, 2 H, J ¼ 6.5 Hz, ArH), 8.39–8.54 (m, 1 H,
ArH) 9.64 (b, 1 H, NH); 13C-NMR (50 MHz, CDCl3) d 100.1,
122.9 (2 ꢂ CH), 123.0 (2 ꢂ CH), 124.7 (2 ꢂ CH), 126.9,
127.5, 128.1 (2 ꢂ CH), 128.6 (2 ꢂ CH), 128.8 (2 ꢂ CH),
132.3, 136.1, 138.3, 138.5, 150.5, 162.0, 164.2; IR (KBr) 3250
(brs, NH), 3087, 1686, 1578, 1501, 1296, 769, 699 cmꢁ1; MS
m/z (relative intensity) 364 (Mþ, 100), 335 (6), 262 (3), 234
(12), 206 (7), 130 (98), 102 (44), 77 (16), 51 (5); Anal. Calcd.
for C23H16N4O: C, 75.81; H, 4.43; N, 15.38. Found: C, 76.12;
H, 4.42; N, 15.14.
N-(5-Isobenzofurancarbonyl)-1,3-diphenyl-5-amino-1H-pyr-
1
azole (24). H-NMR (CDCl3) d 6.78 (s, 1 H, Py-H), 6.95 (s, 1
H, isobenzofurane-H), 7.27–7.50 (m, 10 H, ArH), 7.72–7.89 (m,
3 H, ArH), 8.06 (d, 1 H, J ¼ 6.4 Hz, isobenzofurane-H), 8.5 (b,
1 H, NH); 13C-NMR (CDCl3) d 97.6, 104.1, 122.7, 124.4 (2 ꢂ
CH), 124.8, 125.7 (2 ꢂ CH), 128.5, 128.7, 129.4 (2 ꢂ CH þ
CH), 129.8, 130.0, 131.8, 132.4, 133.9, 135.7, 137.9, 139.4,
151.9, 152.1 165.0; IR (KBr) 3062 (brs, NH), 2924, 1735, 1674,
1558, 1497, 1458, 1367, 1087 cmꢁ1; MS m/z (relative intensity)
409 (Mþ, 4), 364 (100), 336 (5), 313 (6), 262 (4), 234 (12), 206
(12), 180 (5), 131 (4), 103 (10), 91 (9), 77 (27), 55 (6); Anal.
Calcd. for C24H15N3O4; C, 70.41; H, 3.69; N, 10.26. Found: C,
70.34; H, 3.57; N, 10.22.
N-(2-Furancarbonyl)-1,3-diphenyl-5-amino-1H-pyrazole
(20). mp (purified by column chromatography on silica gel)
1
143–145ꢀC; H-NMR (CDCl3, 200 MHz) d 6.54 (dd, 1 H, J ¼
3.6, 1.7 Hz, Furan-H), 7.18 (s, 1 H, Py-H), 7.25 (d, 1 H, J ¼
3.6 Hz, Furan-H), 7.32–7.51 (m, 6 H), 7.56–7.60 (m, 3 H),
7.89 (dd, 2 H, J ¼ 8.0, 1.3 Hz, ArH), 8.34 (b, 1 H, NH); 13C-
NMR (50 MHz, CDCl3) d 95.4, 112.8, 116.4, 124.7 (2 ꢂ CH),
125.8 (2 ꢂ CH), 128.1, 128.6 (3 ꢂ CH), 130.0 (2 ꢂ CH),
133.0, 136.0, 137.9, 144.8, 146.8, 152.0, 154.2; IR (KBr) 3400
(brs, NH), 3277, 3138, 3061, 1672, 1587, 1556, 1537, 1500,
1471, 1415, 1365, 1288, 1228, 1157, 1074, 1012, 954, 883,
763, 692 cmꢁ1; MS m/z (relative intensity) 330 (Mþ, 100),
315 (9), 262 (11), 236 (14), 221 (16), 207 (12), 154 (28), 121
(42), 119 (58), 95 (95), 79 (57), 69 (100), 55 (99); HRMS
Calcd. for C20H15N3O2: 329.1164, Found 329.1167.
N-Quinoline-8-sulfonyl-1,3-diphenyl-5-amino-1H-pyrazole
1
(25). H-NMR (CDCl3, 200 MHz) d 6.38 (s, 1 H, Py-H),
7.25–7.68 (m, 12 H, ArH þ quinoline-H), 8.01 (dd, 1 H, J ¼
8.4, 1.4 Hz, quinoline-H), 8.20 (dd, 1 H, J ¼ 8.4, 1.7 Hz,
quinoline-H), 8.35 (dd, 1 H, J ¼ 7.3, 1.4 Hz, quinoline-H),
8.47 (dd, 1 H, J ¼ 4.3, 1.7 Hz, quinoline-H), 10.2 (b, 1 H,
NH); 13C-NMR (50 MHz, CDCl3) d 96.4, 122.3, 123.7, 125.2
(2 ꢂ CH), 125.5 (2 ꢂ CH), 125.7, 127.4, 128.1, 128.3, 128.5
(2 ꢂ CH), 129.3 (2 ꢂ CH), 131.5, 132.6, 134.0, 135.0, 136.4,
137.1, 137.8, 151.0, 151.4; IR (KBr) 3450 (brs, NH), 3061,
N-(2-Thiophenecarbonyl)-1,3-diphenyl-5-amino-1H-pyraz-
1
1597, 1544, 1502, 1460, 1379, 1173, 1146, 766, 696 cmꢁ1
;
ole (21). [14] H-NMR (CDCl3) d 7.04 (dd, 1 H, J ¼ 4.9, 3.8
MS m/z (relative intensity) 427 (Mþ, 86), 395 (59), 337 (13),
289 (13), 281 (20), 235 (59), 221 (23), 207 (28), 194 (15), 185
(46), 176 (38), 165 (32), 154 (80), 109 (86), 83 (100), 71
(100), 57 (100); HRMS Calcd. for C24H18N4O2S: 427.1150,
Found 427.1123; Anal. Calcd. for C24H18N4O2S: C, 67.59; H,
4.25; N, 13.14. Found: C, 67.25; H, 4.56; N, 12.97.
Hz, thiophene-H), 7.13 (s, 1 H, Py-H), 7.36–7.66 (m, 10 H, ArH),
7.86–7.90 (m, 2 H, thiophene-H), 7.90 (b, 1 H, NH); 13C-NMR
(CDCl3) d 96.0, 124.7 (2 ꢂ CH), 125.8 (2 ꢂ CH), 128.1, 128.2,
128.6 (2 ꢂ CH þ CH), 129.2, 130.1 (2 ꢂ CH), 131.8, 132.9,
136.2, 137.4, 137.8, 152.0, 158.1. IR (KBr) 3061 (brs, NH), 2922,
2851, 1654, 1554, 1537, 1504, 1365, 1283, 1214, 1171, 1065,
1038, 888 cmꢁ1; MS m/z (relative intensity) 345 (Mþ, 42), 236
(4), 207 (3), 111 (100), 102 (11), 83 (2), 77 (10), 51 (3); HRMS
Calcd. for C20H15N3OS: 345.0936, Found 345.0939.
Acknowledgment. The authors are grateful to the China Medi-
cal University (CMU95-191) for financial support.
N-Isoxazole-5-carbonyl-1,3-diphenyl-5-amino-1H-pyrazole
(22). mp (purified by column chromatography on silica gel)
REFERENCES AND NOTES
1
153–155ꢀC; H-NMR (CDCl3) d 7.04 (d, 1H, J ¼ 1.8 Hz, Iso-
[1] Cralg, P. N. In Comprehensive Medicinal Chemistry; Dray-
ton, C. J., Ed.; Pergamon Press: New York, 1991; Vol. 8.
[2] Southon, I. W.; Buckinggham, J. In Dictionary of Alka-
loids; Saxton, J. E., Ed.; Chapman and Hall: London, 1989.
[3] Negwer, M. In Organic-Chemical Drugs and Their Syno-
nyms (An International Survey), 7th ed.; Akademie Verlag GmbH:
Berlin, 1994.
xazole-H), 7.19 (s, 1 H, Py-H), 7.35–7.58 (m, 8 H, ArH), 7.87
(dd, 2 H, J ¼ 6.6, 1.4 Hz, ArH), 8.35 (d, 1 H, J ¼ 1.8 Hz, Iso-
xazole-H), 8.51 (b, 1 H, NH); 13C-NMR (CDCl3) d 96.2,
107.9, 124.7 (2 ꢂ CH), 125.8 (2 ꢂ CH), 128.3, 128.6 (2 ꢂ
CH), 128.9, 130.2 (2 ꢂ CH), 132.7, 135.0, 137.5, 151.4,
151.7, 152.0, 161.5; IR (KBr) 3399 (brs, NH), 3306, 3151,
3085, 1700, 1559, 1498, 1457, 1418, 1364, 1330, 1270, 1204,
1162, 1073, 1018, 825 cmꢁ1; MS m/z (relative intensity) 331
(Mþ, 62), 262 (15), 236 (11), 203 (11), 169 (12), 154 (22),
121 (21), 119 (41), 95 (74), 79 (53), 69 (96), 55 (100); HRMS
Calcd. for C19H14N4O2: 330.1117, Found 330.1187; Anal.
Calcd. for C19H14N4O2: C, 69.68; H, 4.27; N, 16.96. Found:
C, 69.58; H, 4.15; N, 16.86.
[4] For the biological activities of pyrazole derivatives, see:
Singh, P.; Paul, K.; Holzer, W. Bioorg Med Chem 2006, 6, 5061 and
references cited therein.
[5] Lindsley, C. W.; Wisonoski, D. D.; Leister, W. H.; O’Brien,
J. A.; Lemaire, W.; Williams, D. L., Jr.; Burno, M.; Sur, C.; Kinney,
G. G.; Pettibone, D. J.; Tiller, P. R.; Smith, S.; Duggan, M. E.; Hart-
man, G. D.; Conn, P. J.; Huff, J. R. J Med Chem 2004, 47, 5825.
[6] Roppe, J.; Smith, N. D.; Huang, D.; Tehrani, L.; Wang, B.;
Anderson, J.; Brodkin, J.; Chung, J.; Jiang, X.; King, C.; Munoz, B.;
N-(2-Benzofurancarbonyl)-1,3-diphenyl-5-amino-1H-pyraz-
ole (23). mp (purified by column chromatography on silica gel)
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

July 2010
An Efficient One-Pot Synthesis of N-(1,3-Diphenyl-1H-pyrazol-5-yl)amides
837
Varney, M. A.; Prasit, P.; Cosford, N. D. P. J Med Chem 2004, 47,
4645.
[13] For the synthesis of pyrazole derivatives, see: (a) Elguero,
J. In Comprehensive Heterocyclic Chemistry; Katrizky, A., Ed.; Perga-
mon Press: Oxford, 1984; Vol. 5, p 277; (b) Elguero, J. In Compre-
hensive Heterocyclic Chemistry II; Shinkai, I., Ed.; Elsevier: Oxford,
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet