Syntheses, Crystal Structures, and Spectral Characterization of Six Novel Benzimidazolyl Substituted Triaryltriazoles

Article abstract of DOI:10.1002/jhet.2880

Six new benzimidazolyl substituted triaryltriazoles, 3-(2-pyridyl)-4-(p-R-phenyl)-5-(2-benzimidazolyl)-1,2,4-triazoles (L¹: R?=?OCH₃; L²: R?=?CH₃; L³: R?=?H; L⁴: R?=?Br; L⁵: R?=?Cl; L⁶: R?=?F) were successfully synthesized. Yield of L^1–6 is in the range from 61 to 76%. The compounds L^1–6 were characterized by UV–vis, FTIR, ¹H-NMR, ESI-MS spectra, and elemental analysis. Additionally, the absolute configurations of L^1–5 were determined by single crystal X-ray crystallography.

Full text of DOI:10.1002/jhet.2880

Month 2017
Syntheses, Crystal Structures, and Spectral Characterization of Six Novel
Benzimidazolyl Substituted Triaryltriazoles
*
Yong-Fei Zhou, Shi-Pei Zhang, Zhe Feng, Xuan Shen, and Dun-Ru Zhu
State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech
University, Nanjing 210009, China
*
E-mail: zhudr@njtech.edu.cn
Additional Supporting Information may be found in the online version of this article.
Received December 25, 2016
DOI 10.1002/jhet.2880
Published online 00 Month 2017 in Wiley Online Library (wileyonlinelibrary.com).
Six new benzimidazolyl substituted triaryltriazoles, 3-(2-pyridyl)-4-(p-R-phenyl)-5-(2-benzimidazolyl)-
1,2,4-triazoles (L1: R = OCH3; L2: R = CH3; L3: R = H; L4: R = Br; L5: R = Cl; L6: R = F) were successfully
synthesized. Yield of L1–6 is in the range from 61 to 76%. The compounds L1–6 were characterized by
UV–vis, FTIR, 1H-NMR, ESI-MS spectra, and elemental analysis. Additionally, the absolute configurations
of L1–5 were determined by single crystal X-ray crystallography.
J. Heterocyclic Chem., 00, 00 (2017).
INTRODUCTION
RESULTS AND DISCUSSION
Over the past few decades, substituted 1,2,4-triazoles
have attracted widespread attention because of their
interesting pharmacological activities such as antifungus,
antitumor, fungicide, weedicide, and anti-inflammatory
[1]. The 1,2,4-triazoles derivatives are also widely used
in coordination chemistry because of their versatile
coordination modes [2]. Specially, some iron(II)
complexes with substituted triazoles show fascinating
spin crossover properties which can be used as molecular
switches, display devices, sensing, and data storage
materials [3–6].
Several synthesis methods of 3,4,5-trisubstituted 1,2,4-
triazoles have been reported [19]. Here, a modified
method was chosen for the synthesis of our target
compounds (L1–6) due to mild reaction conditions and a
higher yield [20]. The synthetic route of L1–6 was shown
in Scheme 1.
The readily available o-phenylenediamine reacting with
(L)-lactic acid under 4 M hydrochloric acid solution gave
(S)-2-(α-hydroxyethyl)-benzimidazole (I) in a yield of
67.7% [21]. Then, benzimidazole-2-carboxylic acid (II)
was obtained in a yield of 75.6% by stirring I with
potassium permanganate in NaOH aqueous solution at
80°C [22]. II treated with sulfoxide chloride in
anhydrous MeCN at 80°C produced the benzimidazole-
2-carbonyl chloride (III) in a yield of 97.5%. 2-Picolinic
acid reacting with anhydrous ethanol under the existence
of 98% concentrated sulfuric acid gave ethyl pyridine-
2-carboxylate (IV) [23]. Brief treatment of IV with 80%
hydrazine hydrate afforded pyridine-2-carbonylhydrazine
(V) in 48.2% yield. Then, N-(2-pyridylcarbonyl)-N0-
(2-benzimidazolylcarbonyl)hydrazine (VI) was obtained
in a yield of 50.0% by stirring V with the freshly III in
the chloroform at 60°C [24]. The cyclization reaction of
VI with p-toluenesulfonyl chloride under existence of
anhydrous potassium carbonate produced the 2-(2-
pyridyl)-5-(2-benzimidazolyl)-1,3,4-oxadiazole (VII) in
64.2% yield [25]. Finally, under an argon atmosphere,
VII reacting with p-R-aniline in o-dichlorobenzene at
Recently,
a
series of asymmetrically 3,4,5-
triarylsubstituted 1,2,4-triazoles and their metal complexes
have been synthesized by our group [7–17]. However,
most of the substituted groups on the 1,2,4-triazoles are
pyridyl, phenyl, quinolyl, and five-membered aromatic
rings such as pyrrolyl and imidazolyl. Substituted 1,2,4-
triazoles with benzimidazolyl (bzim) group have been less
reported so far [18]. As a continuation of our investigation
of the asymmetrically substituted triaryltriazoles, we
present here the first syntheses of six new bzim-
substituted triaryltriazoles, 3-(2-pyridyl)-4-(p-R-phenyl)-
5-(2-benzimidazolyl)-1,2,4-triazoles (L1: R = OCH3; L2:
R = CH3; L3: R = H; L4: R = Br; L5: R = Cl; L6: R = F)
(Scheme 1). The compounds L1–6 were fully characterized
by UV–vis, FTIR, 1H-NMR, ESI-MS spectra, and
elemental analysis. The molecular structures of L1–5 were
also determined by X-ray crystallography.
© 2017 Wiley Periodicals, Inc.

Y.-F. Zhou, S.-P. Zhang, Z. Feng, X. Shen, and D.-R. Zhu
Vol 000
Scheme 1
190°C gave the corresponding 1,2,4-triazoles L1–6 (yield:
L1, 76.3%; L2, 71.9%; L3, 60.9%; L4, 69.3%; L5, 71.8%;
L6, 67.1%) [26].
(Table 1). The crystal structures of L1–5 with atom-
labeling scheme are shown in Figure 1, and the selected
bond distances and angles are summarized in Table 2.
The X-ray crystallography indicates that both L1 and L3
crystallize in the monoclinic space group P21/n, and both
L4 and L5 crystallize in the monoclinic space group
P21/c, while L2 crystallizes in the triclinic space group
The asymmetrical 3,4,5-triaryltriazoles L1–6 were fully
1
characterized by UV–vis, FTIR, H-NMR, ESI-MS, and
elemental analysis. The molecular structures of L1–5 were
also determined by single crystal X-ray diffraction
Table 1
Crystallographic data for L1ꢀ5
.
Compounds
L1
L2 L3
L4
L5
Empirical formula
Formula weight
Crystal system
Space group
T (K)
a (Å)
b (Å)
c (Å)
α (°)
C21H16N6O
368.40
Monoclinic
P21/n
296(2)
10.935(7)
9.835(6)
17.540(11)
90
93.521(7)
90
1883(2)
4
1.300
C21H16N6 C20H14N6
C20H13N6Br
417.27
Monoclinic
P21/c
296(2)
8.7055(9)
10.4277(11)
19.916(2)
90
96.342(10)
90
1796.9(3)
4
1.542
C20H13N6Cl
372.81
Monoclinic
P21/c
296(2)
8.589(3)
10.418(4)
19.671(7)
90
96.074(5)
90
1750.2(11)
4
1.415
352.40
Triclinic
P-1
338.37
Monoclinic
P21/n
296(2)
296(2)
13.847(5)
5.575(2)
21.390(8)
90
97.868(5)
90
1635.8(11)
4
9.467(2)
9.781(2)
11.928(3)
68.759(2)
88.936(3)
62.274(3)
896.1(4)
2
β (°)
γ (°)
V (Å3)
Z
Dc (g cmꢀ3
)
1.306
1.374
μ (mmꢀ1
F (000)
)
0.085
768
0.13 × 0.12 × 0.09
2.14–25.00
12 913
0.082
0.087
2.305
840
0.13 × 0.10 × 0.09
2.06–25.00
12 392
0.236
768
0.14 × 0.11 × 0.08
2.08–25.00
12 105
368
704
Crystal size (mm3)
θ range (°)
0.14 × 0.10 × 0.07
1.86–25.00
6397
0.14 × 0.12 × 0.10
1.65–25.00
10 958
Reflections collected
Independent reflections 3317 [Rint = 0.0256]
3126 [Rint = 0.0199] 2877 [Rint = 0.0531] 3164 [Rint = 0.0333] 3085 [Rint = 0.0554]
Reflections observed
2738
2571
1627
2369
2022
[I > 2σ(I)]
Data/restraints/
3317/4/253
3126/3/244
2877/4/235
3164/1/244
3085/3/244
parameters
Goodness-of-fit on F2
R/wR [I > 2σ(I)]
R/wR (all data)
1.115
1.095
1.067
1.060
1.066
0.0556/0.1715
0.0650/0.1805
0.418, ꢀ0.451
0.0599/0.1747
0.0696/0.1850
0.385, ꢀ0.473
0.0680/0.1892
0.1219/0.2162
0.409, ꢀ0.419
0.0440/0.1148
0.0648/0.1222
0.441, ꢀ0.475
0.0573/0.1468
0.0931/0.1632
0.400, ꢀ0.475
Max., min. Δρ (e Åꢀ3
)
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2017
Syntheses, Crystal Structures, and Spectral Characterization of Six Novel
Benzimidazolyl Substituted Triaryltriazoles
Figure 1. Views of L1–5 showing the atom-labeling scheme. Hydrogen atoms are omitted for clarity. [Color figure can be viewed at wileyonlinelibrary.com]
P-1. All the L1–5 ligands consist of three aromatic rings
and one central 1,2,4-triazole ring. In L1–3
the
while there is only one kind of C―H···π interaction in L3
involving C20―H20A and the bzim ring (C20···πii = 3.720
(7) Å and ∠C20―H20A⋯πii = 161°). There are two kinds
of C―H···π interactions in L2 including (i) C2―H2A and
the p-methylphenyl ring (C2···πii = 3.878(9) Å and
∠C2―H2A⋯πii = 161°) and (ii) C16―H16A and the
,
substituted pyridyl ring, phenyl ring, and bzim ring lie in
a propeller arrangement around the central 1,2,4-triazole
ring, whereas in L4–5 the substituted pyridyl ring, bzim
ring, and the central 1,2,4-triazole ring almost share a
common plane (Table 3). These relevant dihedral angles
are listed in Table 3.
triazole ring (C16···πiii
=
3.815(3)
Å
and
∠C16―H16A⋯πiii = 137°). In addition, two types of
C―H···π interactions are found in L4 involving (i)
C13―H13A and the p-bromophenyl ring (C13···
πiii = 3.532(9) Å and ∠C13―H13A⋯πiii = 121°) and (ii)
C17―H17A and the bzim ring (C17···πiv = 3.584(9) Å and
∠C17―H17A⋯πiv = 158°), whereas there is one kind of
C―H···π interaction in L5 between C19―H19A and the
Although the bond lengths and bond angles of L1–5 are
similar and can be comparable with the related triazoles
[20,23,27,28], their intermolecular interactions are quite
different. It is worthwhile to note that in all compounds,
there is a strong N5―H5A···N3 hydrogen bond and a weak
C10―H10A···N2 hydrogen bond involving the bzim and
the central 1,2,4-triazole (Fig. 2 and Table 4). However, in
L4, there is a weak C―H···Br hydrogen bond involving the
pyridyl and the neighboring p-bromophenyl group
(H1A···Br1ii = 2.993(3) Å), and in L5 a weak C―H···Cl
hydrogen bond involving the pyridyl and the neighboring
p-chlorophenyl group (H1A···Cl1ii = 2.927(5) Å) is also
observed (Table 4) [29]. There are three kinds of C―H···π
interactions in L1 involving (i) C16―H16A and the pyridyl
bzim ring (C19···πiii
= 3.555(2) Å and ∠C19―
H19A⋯πiii = 157°) (Table 4). Furthermore, a weak
intermolecular π–π interaction is observed in L4 between
the triazole ring and the pyridyl ring (Fig. 3 and Table 5).
These different intermolecular interactions have an
important influence on the crystal packing of L1–5 as shown
in Figure 2.
ring (C16···πii
=
3.755(4)
Å
and ∠C16―
EXPERIMENTAL
H16A⋯πii = 167°), (ii) C19―H19A and the bzim ring
(C19···πiii = 3.814(9) Å and ∠C19―H19A⋯πiii = 132°),
and (iii) C21―H21A and the p-methoxyphenyl ring
(C21···πiv = 3.757(7) Å and ∠C21―H21A⋯πiv = 133°),
All chemicals and solvents purchased were of analytical
grade and were used without further purification. Melting
points were determined with an X-4 digital microscope
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Y.-F. Zhou, S.-P. Zhang, Z. Feng, X. Shen, and D.-R. Zhu
Vol 000
Table 3
The dihedral angles (°) for L1ꢀ5
.
Compounds
Py/Trz
Ph/Trz
Bzim/Trz
L1
39.18
44.31
32.86
3.20
84.35
86.30
75.40
77.47
78.22
20.00
20.72
27.82
12.13
10.82
L2
L3
L4
L5
4.92
melting-point apparatus (Beijing) and are uncorrected.
Ultraviolet–visible spectra were recorded on a Perkin-
Elmer Lambda 35 spectrophotometer at room temperature
in methanol solution. Fourier transform infrared spectra
were recorded on a Nicolet 380 FTIR instrument using
1
KBr disks in the range 4000–400 cmꢀ1. H-NMR spectra
were measured on a Bruker AM 400-MHz spectrometer
at ambient temperature in DMSO-d6. Chemical shifts are
reported in parts per million (ppm) downfield from TMS.
Electrospray ionization mass spectrum (ESI-MS) was
recorded with an LCQ ADVANTAGE MAX mass
spectrometer, with MeOH on the mobile phase; the flow
rate of the mobile phase was 0.2 cm3 minꢀ1. The spray
voltage, the capillary voltage, and the capillary
temperature were 4 kV, 40 V, and 260°C, respectively.
Elemental analyses (C, H, N) were carried out with a
Thermo Finnigan Flash 1112A elemental analyzer.
(S)-2-(α-Hydroxyethyl)-benzimidazole (I). o-Phenylene-
diamine (6.48 g, 60 mmol), (L)-lactic acid (8 mL), and 4 M
hydrochloric acid (60 mL) were heated under reflux for
2 h. Then, the solution was neutralized with 25%
ammonia solution to afford the product as a yellow solid.
The solid was recrystallized from water to obtain I as
yellow plate crystals (6.58 g, 67.7%), mp 180–181°C.
FTIR (ν, cmꢀ1): 3177, 3057, 2971, 1624, 1435, 1306,
1104, 804, 796.
Benzimidazole-2-carboxylic acid (II).
I (3.24 g,
20 mmol) and sodium hydroxide (0.96 g, 24 mmol)
were dissolved in 60 mL boiling water. Potassium
permanganate (12.64 g, 80 mmol) was added in batches
with stirring over a period of 1 h. The hot solution was
filtered, and precipitate was washed several times with
hot water (3 × 50 mL). The filtrate was cooled and
neutralized carefully with 4 M hydrochloric acid solution.
The precipitated benzimidazole-2-carboxylic acid was
filtered as primrose yellow solid (2.45 g, 75.6%), mp
168–169°C. FTIR (ν, cmꢀ1): 3577, 3144, 3030, 2967,
1651, 1518, 1481, 1396, 1347, 841, 772.
Benzimidazole-2-carbonyl chloride (III).
Sulfoxide
chloride (5 mL) was added dropwise to a suspension
solution of II (1.62 g, 10 mmol) in anhydrous acetonitrile
(20 mL) surrounded by an ice-water bath. The mixture
was refluxed for 4 h. The solvent was evaporated to
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2017
Syntheses, Crystal Structures, and Spectral Characterization of Six Novel
Benzimidazolyl Substituted Triaryltriazoles
Figure 2. Views of the intermolecular hydrogen bonds and C―H···π interactions for L1–5. [Color figure can be viewed at wileyonlinelibrary.com]
Table 4
The hydrogen bonds and C―H···π interactions in L1ꢀ5
.
Compounds
D―H···A
D―H/Å
H···A/Å
D···A/Å
∠D―H···A/°
N5―H5A···N3i
0.86
0.93
0.93
0.93
0.96
0.86
0.93
0.93
0.93
0.86
0.93
0.93
0.86
0.93
0.93
0.93
0.93
0.86
0.93
0.93
0.93
2.12
2.70
2.84
3.13
3.04
2.09
2.60
2.99
3.08
2.10
2.63
2.83
2.11
2.68
2.99
2.96
2.70
2.10
2.66
2.93
2.68
2.932(4)
3.394(8)
3.755(4)
3.814(9)
3.757(7)
2.925(4)
3.344(2)
3.878(9)
3.815(3)
2.919(9)
3.373(2)
3.720(7)
2.945(4)
3.399(7)
3.903(2)
3.532(9)
3.584(9)
2.937(0)
3.384(6)
3.849(8)
3.555(2)
157
132
167
132
133
164
137
161
137
160
137
161
163
134
167
121
158
162
135
172
157
C10―H10A···N2i
C16―H16A···π (Py)ii
C19―H19A···π (Bzim)iii
C21―H21A···π (Ph)iv
N5―H5A···N3i
L1
L2
L3
L4
C10―H10A···N2i
C2―H2A···π (Ph)ii
C16―H16A···π (Trz)iii
N5―H5A···N3i
C10―H10A···N2i
C20―H20A···π (Bzim)ii
N5―H5A···N3i
C10―H10A···N2i
C1―H1A···Br1ii
C13―H13A···π (Ph)iii
C17―H17A···π (Ph)iv
N5―H5A···N3i
C10―H10A···N2i
C1―H1A···Cl1ii
L5
C19―H19A···π (Ph)iii
Symmetry codes: L1: (i) 1 ꢀ x, ꢀy, ꢀz; (ii) 3/2 ꢀ x, 1/2 + y, 1/2 ꢀ z; (iii) 2 ꢀ x, ꢀy, ꢀz; (iv) 5/2 ꢀ x, 1/2 + y, 1/2 ꢀ z; L2: (i) 1 ꢀ x,
1 ꢀ y, ꢀz; (ii) ꢀ1 ꢀ x, 2 ꢀ y, ꢀz; (iii) ꢀx, 1 ꢀ y, ꢀz; L3: (i) 2 ꢀ x, 2 ꢀ y, ꢀz; (ii) x, ꢀ1 + y, z; L4: (i) 2 ꢀ x, 1 ꢀ y, 1 ꢀ z; (ii) x,
1/2 ꢀ y, 1/2 + z; (iii) 1 ꢀ x, 1/2 + y, 1/2 ꢀ z; (iv) ꢀ1 + x, y, z; L5: (i) ꢀ1 ꢀ x, 2 ꢀ y, ꢀz; (ii) x, 5/2 ꢀ y, ꢀ1/2 + z; (iii) 1 + x, y, z.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Y.-F. Zhou, S.-P. Zhang, Z. Feng, X. Shen, and D.-R. Zhu
Vol 000
colorless needle crystals (10.85 g, 48.2% for two-step
reaction), mp 97–100°C. FTIR (ν, cmꢀ1): 3289, 3158,
1675, 1594, 1570, 1521, 1400, 1000, 819, 751.
N-(2-Pyridylcarbonyl)-N’-(2-benzimidazolylcarbonyl)
hydrazine (VI). The chloroform solution of V (1.51 g,
11 mmol) and
4 mL triethylamine were added
dropwise to the fresh chloroform suspension solution of
III. The mixture was refluxed for 12 h. The hot
solution was filtered, and the filtrate was evaporated to
dryness under reduced pressure. Adding 15 mL water
and filtering, the residue was recrystallized from
ethanol to give VI as yellow solids (1.40 g, 50.0%).
FTIR (ν, cmꢀ1): 3340, 3232, 3057, 1693, 1666, 1621,
1546, 1512, 1445, 1319, 996, 750. 1H-NMR (DMSO-
d6/400 MHz), δ (ppm): 13.46 (s, 1H), 10.68–10.78 (br,
2H, NH), 8.72 (s, 1H, PyH), 8.06–8.07 (d, 2H, ArH),
7.78 (s, 1H, PyH), 7.68 (s, 1H, PyH), 7.58 (s, 1H,
PyH), 7.34 (s, 2H, ArH).
2-(2-Pyridyl)-5-(2-benzimidazolyl)-1,3,4-oxadiazole
(VII).
A
mixture of VI (1.4 g,
5
mmol),
Figure 3. View of crystal packing for L4 showing π···π and C―H···π
interactions. [Color figure can be viewed at wileyonlinelibrary.com]
p-toluenesulfonyl chloride (2.38 g, 12.5 mmol), and
anhydrous potassium carbonate (1.73 g, 12.5 mmol) in
acetonitrile (80 mL) was stirred for 12 h at 50°C. Then,
20 mL water was added to above suspension solution and
stirred for 2 h at 80°C. The solution was evaporated to
dryness under reduced pressure and added 30 mL water,
20 mL ethanol, and 4 mL 4 M sodium hydroxide
solution to stir for 4 h at 80°C. The hot solution was
filtered, and the filtrate was cooled and neutralized
carefully with 4 M hydrochloric acid solution. The
precipitate was filtered and recrystallized from ethanol as
primrose yellow solids (841 mg, 64.2%). FTIR (ν, cmꢀ1):
3145, 3114, 3063, 1601, 1555, 1432, 1401, 1318, 793,
742. 1H-NMR (DMSO-d6/400 MHz), δ (ppm): 14.07
(br, 1H), 8.92 (s, 1H, PyH), 8.37 (s, 1H, PyH), 8.18
(s, 1H, PyH), 7.77 (s, 3H, PyH, PhH), 7.43 (s, 2H, PhH).
Table 5
The π···π interaction in L4.
π···π
interaction
Cent···cent
(Å)
Dihedral angle
(°)
Compound
L4
π (Trz)···π (Py)i
4.040(6)
3.21
Symmetry code: (i) 1 ꢀ x, 1 ꢀ y, 1 ꢀ z.
dryness under reduced pressure to obtain a yellow solid
(1.76 g, 97.5%). FTIR (ν, cmꢀ1): 3239, 3089, 2964,
1739, 1526, 1368, 1230, 1086, 875, 770.
Ethyl pyridine-2-carboxylate (IV). Ninety-eight percent
concentrated sulfuric acid (10 mL) was added dropwise to
a solution of 2-picolinic acid (24.6 g, 0.2 mol) in
anhydrous ethanol (140 mL) surrounded by an ice-water
bath. The mixture was refluxed for 24 h. Upon cooling to
ambient temperature, the product was poured into 80 mL
ice water. The resulting solution was neutralized to
pH = 7–8 with a solution of potassium carbonate. The
precipitate was filtered, and the filtrate was extracted with
ether (3 × 100 mL). After drying over magnesium sulfate,
the organic phases were evaporated to dryness under
reduced pressure. The unpurified ester can be used for
next hydrazinolysis.
3-(2-Pyridyl)-4-(p-R-phenyl)-5-(2-benzimidazolyl)-1,2,4-
triazoles (L1–6). VII (262 mg, 1 mmol), p-Toluenesulfonic
acid (47.5 mg, 0.25 mmol), and 1.2 mmol p-R-aniline were
added to o-dichlorobenzene (6 mL), then, the mixture was
heated to 190°C for 4 h under argon atmosphere. After all
starting material had been consumed, the excess solvent was
removed under reduced pressure. The residue was washed
with diethyl ether and recrystallized from methanol to obtain
the corresponding L1–6
.
3-(2-Pyridyl)-4-(p-methoxyphenyl)-5-(2-benzimidazolyl)-1,2,4-
triazole (L1). This compound was obtained as colorless
block crystals (281 mg, 76.3%). UV (MeOH, nm): 208
(2.84), 296 (2.09). FTIR (ν, cmꢀ1): 3133, 3069, 2968,
1
Pyridine-2-carbonylhydrazine (V). A mixture of above
ester IV, 80% hydrazine hydrate (15 mL), and ethanol
(50 mL) was refluxed for 12 h. Then, the solution was
evaporated to dryness, and the resulting white solid was
recrystallized from anhydrous ethanol to give V as
1589, 1513, 1429, 1406, 1251, 1024, 835, 747. H-NMR
(DMSO-d6/400 MHz), δ (ppm): 13.47 (s, 1H), 8.45–8.46
(d, 1H, PyH), 7.92–7.98 (dd, 2H, PyH), 7.53 (s, 2H, ArH),
7.42–7.44 (t, 1H, PyH), 7.36–7.38 (d, 2H, ArH), 7.18–7.28
(d, 2H, ArH), 6.94–6.96 (d, 2H, ArH), 3.80 (s, 3H, CH3).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2017
Syntheses, Crystal Structures, and Spectral Characterization of Six Novel
Benzimidazolyl Substituted Triaryltriazoles
ESI-MS: m/z 369.2 (M + H)+. Anal. Calcd for C21H16N6O
(%): C, 68.47; H, 4.38; N, 22.81. Found (%): C, 68.62; H,
4.63; N, 23.04.
FTIR (ν, cmꢀ1): 3215, 3063, 1585, 1510, 1429, 1402, 1336,
1231, 1156, 846, 746. H-NMR (DMSO-d6/400 MHz), δ
1
(ppm): 13.52 (s, 1H), 8.40–8.41 (d, 1H, PyH), 8.06–8.08
(d, 1H, PyH), 7.94–7.98 (t, 1H, PyH), 7.53–7.56 (q, 4H,
ArH), 7.42–7.45 (t, 1H, PyH), 7.26–7.31 (t, 3H, ArH),
7.18 (s, 1H, ArH). ESI-MS: m/z 357.2 (M + H)+. Anal.
Calcd for C20H13N6F (%): C, 67.41; H, 3.68; N, 23.58.
Found (%): C, 66.96; H, 3.89; N, 23.50.
3-(2-Pyridyl)-4-(p-methylphenyl)-5-(2-benzimidazolyl)-1,2,4-
triazole (L2). This compound was obtained as a colorless
block crystal (253 mg, 71.9%). UV (MeOH, nm): 207
(2.57), 296 (1.77). FTIR (ν, cmꢀ1): 3136, 3067, 2977,
1590, 1512, 1431, 1407, 1335, 826, 743. 1H-NMR
(DMSO-d6/400 MHz), δ (ppm): 13.48 (s, 1H), 8.43–8.44
(d, 1H, PyH), 7.93–7.99 (dd, 2H, PyH), 7.50–7.56
(q, 2H, ArH), 7.42–7.45 (t, 1H, PyH), 7.31–7.33 (d, 2H,
ArH), 7.27–7.28 (d, 1H, ArH), 7.21–7.23 (d, 2H, ArH),
7.16–7.19 (t, 1H, ArH), 2.37 (s, 3H, CH3). ESI-MS: m/z
353.2 (M + H)+. Anal. Calcd for C21H16N6 (%):
C, 71.58; H, 4.58; N, 23.85. Found (%): C, 71.76;
H, 4.77; N, 24.17.
Single-crystal X-ray diffraction analysis of L1–5
.
The
well-shaped single crystals of L1–5 were selected for
lattice parameter determination and collection of intensity
data at 296 K on a Bruker SMART CCD diffractometer
with a detector distance of 5 cm and frame exposure time
of 10 s by using a graphite-monochromated Mo Kα
(λ = 0.71073 Å) radiation. The structures were all solved
by direct methods and refined on F2 by full-matrix least
squares procedures using SHELXTL software [30]. All
non-hydrogen atoms were anisotropically refined. All H
atoms were located from a difference map and refined
isotropically. Details on crystal data of L1–5 are
summarized in Table 1.
3-(2-Pyridyl)-4-phenyl-5-(2-benzimidazolyl)-1,2,4-triazole
(L3). This compound was obtained as colorless block
crystals (206 mg, 60.9%). UV (MeOH, nm): 207 (2.76),
298 (2.00). FTIR (ν, cmꢀ1): 3128, 3066, 1585, 1497,
1430, 1406, 1335, 793, 743. 1H-NMR (DMSO-
d6/400 MHz), δ (ppm): 13.56 (br, 1H), 8.39–8.40 (d, 1H,
PyH), 8.00–8.02 (d, 1H, PyH), 7.93–7.97 (t, 1H, PyH),
7.50–7.52 (d, 2H, ArH), 7.41–7.47 (t, 6H, PyH, ArH),
7.22 (s, 2H, ArH). ESI-MS: m/z 339.3 (M + H)+. Anal.
Calcd for C20H14N6 (%): C, 70.99; H, 4.17; N, 24.84.
Found (%): C, 71.05; H, 4.26; N, 25.23.
CCDC 1523844 (L1), 1523845 (L2), 1523846 (L3),
1523847 (L4), and 1523848 (L5) contain the supplementary
crystallographic data for this article. These data can be
obtained free of charge from the Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
3-(2-Pyridyl)-4-(p-bromophenyl)-5-(2-benzimidazolyl)-1,2,4-
triazole (L4). This compound was obtained as colorless
Acknowledgements. This work was funded by the National
Natural Science Foundation of China (Nos. 20771059,
21476115).
block crystals (289 mg, 69.3%). UV (MeOH, nm): 208
(2.91), 301 (2.55). FTIR (ν, cmꢀ1): 3135, 3060, 1585,
1490, 1431, 1403, 1334, 1069, 835, 760. 1H-NMR
(DMSO-d6/400 MHz), δ (ppm): 13.54 (br, 1H), 8.41–8.42
(d, 1H, PyH), 8.08–8.10 (d, 1H, PyH), 7.96–7.99 (t, 1H,
PyH), 7.64–7.66 (d, 2H, ArH), 7.52–7.54 (d, 2H, ArH),
7.47 (s, 1H, PyH), 7.42–7.45 (t, 2H, ArH), 7.23 (s, 2H,
ArH). ESI-MS: m/z 417.2 (M + H)+. Anal. Calcd for
C20H13N6Br (%): C, 57.57; H, 3.14; N, 20.14. Found (%):
C, 57.78; H, 3.36; N, 20.42.
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DOI 10.1002/jhet

Y.-F. Zhou, S.-P. Zhang, Z. Feng, X. Shen, and D.-R. Zhu
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DOI 10.1002/jhet