One-pot synthesis of [1,2,4]Triazolo[1,5-a]pyridines from azines and benzylidenemalononitriles via copper-catalyzed tandem cyclization

Article abstract of DOI:10.1016/j.tet.2018.06.002

A simple and efficient copper-catalyzed tandem radical cyclization reaction has been discovered for the synthesis of triaryl [1,2,4]triazolo[1,5-a]pyridines from easily accessible azines and benzylidenmalononitriles. The new transformation involves multip

Full text of DOI:10.1016/j.tet.2018.06.002

Accepted Manuscript
One-Pot Synthesis of [1,2,4]Triazolo[1,5-a]pyridines from Azines and
Benzylidenemalononitriles via Copper-Catalyzed Tandem Cyclization
Jianguang Lv, Zhiqing He, Jianmin Zhang, Yuwei Guo, Ziwei Han, Xinhua Bao
PII:
S0040-4020(18)30671-9
10.1016/j.tet.2018.06.002
TET 29598
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 11 April 2018
Revised Date: 24 May 2018
Accepted Date: 4 June 2018
Please cite this article as: Lv J, He Z, Zhang J, Guo Y, Han Z, Bao X, One-Pot Synthesis of
[1,2,4]Triazolo[1,5-a]pyridines from Azines and Benzylidenemalononitriles via Copper-Catalyzed
Tandem Cyclization, Tetrahedron (2018), doi: 10.1016/j.tet.2018.06.002.
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One-Pot Synthesis of [1,2,4]Triazolo[1,5-
a]pyridines from Azines and
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Benzylidenemalononitriles via Copper-
Catalyzed Tandem Cyclization
Jianguang Lv,a, & Zhiqing He,a, & Jianmin Zhang,*,a,b Yuwei Guo,a Ziwei Han,a and Xinhua Bao,a
aDepartment of Chemistry, Innovative Drug Research Center, Shanghai University, Shanghai 200444, China
bKey Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of
Science, Shanghai 200032, China

Tetrahedron
1
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Tetrahedron
journal homepage: www.elsevier.com
One-Pot Synthesis of [1,2,4]Triazolo[1,5-a]pyridines from Azines and
Benzylidenemalononitriles via Copper-Catalyzed Tandem Cyclization
Jianguang Lv,a, & Zhiqing He,a, & Jianmin Zhang,*,a,b Yuwei Guo,a Ziwei Han,a and Xinhua Bao,a
aDepartment of Chemistry, Innovative Drug Research Center, Shanghai University, Shanghai 200444, China
bKey Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, Shanghai 200032, China
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
A simple and efficient copper-catalyzed tandem radical cyclization reaction has been discovered
for the synthesis of triaryl [1,2,4]triazolo[1,5-a]pyridines from easily accessible azines and
benzylidenmalononitriles. The new transformation involves multiple C-H/C-C bonds cleavage
and C-C/C-N bonds formation, with extrusion of gaseous hydrogen and methane. A wide variety
of substrates with different functional groups could be converted into the corresponding
products in good yields. The fused heterocycles have strong blue fluorescence with large Strokes
shifts and high quantum yields.
Available online
Keywords:
[1,2,4]triazolo[1,5-a]pyridine
Copper-catalyzed
Demethylation
Fluorescence
Tandem Cyclization
2016 Elsevier Ltd. All rights reserved.
1. Introduction
construct both pyridine and triazole moieties within one
channel had been rarely reported due to the complexity and
Triazolopyridines represent an important class of
nitrogen-rich heterocyclic aromatic compounds. The 1,2,4-
triazole unit can be found in numerous molecules with
various biological activities, including kinase inhibitor1,
antibacterial2, and antioxidative3. Their applications in
material chemistry and other fields have been also explored.4
During the past decades, a number of synthetic routes to
efficiency of forming multiple bonds.10 For instance,
condensation
of
arylmethylenemalononitriles
with
cyanoacetohydrazides led to a range of highly substituted
triazolopyridines (Scheme 1, route f).11 In 2013, Alizadeh
and his co-workers studied on the one-pot synthesis of
[1,2,4]triazolo[1,5-
multi-component reactions from four acyclic fragments,
namely dimethyl acetylenedicaroxylate,
benzylidenehydrazines, aryl aldehydes and malononitrile
Scheme 2, route g).11e Whereas only alkynes with strong
a]pyridines through the iodine-catalyzed
construct [1,2,4]triazolo[1,5-a]pyridines had been revealed.
Based on different available raw materials, the syntheses can
be divided into three main strategies: 1) pyridines and their
derivatives; 2) triazoles and their derivatives; 3) multiple
components. Representative examples included oxidative
cyclization of pyridylimidamides5a-j or guanidyl pyridines
(
electron deficient groups can be applied in this method, the
new strategy could directly introduce multi-functionalities
into triazolopyridines via a sequential 1,4-dihydropyridine
(
Scheme 1, route a),5k tandem addition/cyclization of 2-
construction and C
molecular iodine.
−N bond formation in the presence of
aminopyridines with nitriles catalyzed by aluminium
trichloride,6a copper catalysts6b-d
Scheme 1, route b),
coupling reactions of 2-chloropyridines with thiadiazoles
Scheme 1, route c),7 cyclization of aliphatic and aromatic
acids or their derivatives with 1,2-diaminopyridium salts
generated by reacting 2-amninopyridines with
hydroxylamine-
-sulfonic acid (Scheme 1, route d),8
(
2. Results and discussion
(
Based on our previous experiences in radical synthesis of
heterocycles,12 herein we report on an efficient copper-
catalyzed one-pot elaboration of multi-substituted
O
[1,2,4]triazolo[1,5-
a]pyridines from readily accessible
pyrolysis/cyclization of triazole functionalized with an
azines and benzylidenemalononitriles (Scheme 2, route h).
alkynyl group (Scheme 1, route e).9 A majority of
conventional
protocols
chose
easily
available
aminopyridines and their derivatives as the initial synthetic
point to establish the adjacent triazole nucleus by forming
one or two new bonds. Direct approaches to simultaneously

2
Tetrahedron
ACCEPTED MANUSCRIPT
comparable results as DMSO (Table 1, entries 6-11). The
reaction was not further improved by adding molecular
sieves, but the yield was slightly decreased by other
additives such as -CPBA and 1,10-phenanthroline (Table
, entries 12-14). Water and even mild base K2CO3
m
1
dramatically affected the reaction (Table 1, entries 15-16).
Reducing catalyst loadings lowered the yield, but the
increasement could not further improve the conversion
(
Table 1, entries 17-18). Oxygen was important to this
catalytic system, by contrast, the desired product was
obtained in only 22% yield under N2 atmosphere (Table 1
,
entries 19-20). The optimal condition for this multi-
component reaction was therefore established as fellows: 1a
(0.5 mmol), 2a (1.0 mmol), Cu (0.1 mmol) in dry DMSO
(10 mL) at 100 oC for 8 h under air (Table 1, entry 3).
Table 1
Scheme
[1,2,4]Triazolo[1,5-
1
Typically traditional synthetic routes to
]pyridines.
a
Screening of the reaction conditionsa
Entry
1
Catalyst (mmol)
CuCl (0.1)
—
Additive
—
Solvent
DMSO
DMSO
DMSO
DMSO
DMSO
NMP
Yieldb(%)
66
2
—
Trace
74
3
Cu (0.1)
CuI (0.1)
Cu2O (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.1)
Cu (0.05)
Cu (0.15)
Cu (0.1)
Cu (0.1)
—
4
—
47
5
—
66
6
—
17
7
—
Toluene
DMF
Trace
50
8
—
9
—
Dioxane
HOAc
10
10
11
12
13
14
15
16
17
18
19c
20d
—
10
—
Pyridine
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
Trace
62
Scheme 2 One-pot synthesis of [1,2,4]Triazolo[1,5-a]pyridines.
m-CPBA
4Å-MS
Phen
K2CO3
H2O
—
73
53
Trace
30
52
—
71
O2
61
N2
22
a) Reaction conditions: 1a (0.5 mmol), 2a (1.0 mmol), solvent (10 mL),
100 oC, 8 h, under air atmosphere. b) Isolated yields of 3aa based on 1a
c) Under oxygen atmosphere. d) Under nitrogen atmosphere.
.
Fig. 1 X-ray Crystallographic Structure of 3aa
.
We chose (1
1a 0.5 mmol) and 2-benzylidenemalononitrile
1.0mmol) as starting materials in our initial reaction
optimization (Table ). Various azines and
benzylidenmalononitriles can be easily obtained from
arylketones with hydrazines, and arylaldehydes with
malononitrile respectively (see in supporting information).
In the presence of CuCl (0.1 mmol) using dry DMSO (10mL)
as solvent under air atmosphere, 2,5,7-triphenyl-[1,2,4]-
E
, 2
E
)-1,2-bis(1-phenylethylidene)hydra-zine
With the optimized reaction conditions in hand, we
further investigated the applicability of this new catalytic
reaction with a broad spectrum of substrates (Table 2). In
general, azines bearing electron-donating groups on the para
positions of the phenyl rings led to higher yields than those
(
,
(
2a
,
1
bearing electron-withdrawing groups (Table 2, 3aa-3ea).
Azines that contains nitro substituent would inhibit the
reaction, however, benzylidenmalononitriles bearing
strongly electron-withdrawing nitro group could still give
the desired products in moderate yields (3ag and 3ai).
triazolo[1,5-a]pyridine-8-carbonitrile (3aa) was obtained in
o
66% isolated yield at 100 C after 8 h (Table 1, entry 1).
The structure of 3aa was unambiguously confirmed by
single crystal X-ray diffraction analysis (Fig. 1)13. Notably,
the reaction hardly took place without the copper catalyst
Lower yields were observed when ortho- and meta
-
substituted azines were used (3fa 3ka), probably due to
-
steric effects. Furthermore, Naphthalyl and even
heterocyclic substances were also tolerated in this reaction
(
Table 1, entry 2). While other copper catalysts were also
(3ma-3ao). It is worth noting that different halogenated
applicable, copper powder was found to be the best for the
reaction, affording 3aa in 74% yield (Table 1, entries 3-5).
Other common solvents such as NMP, toluene, DMF, 1,4-
dioxane, acetic acid or pyridine could not achieve
triazolopyridines could be easily realized from this method,
which are interesting intermediates and building blocks for
synthesis of complicated heterocycles (3da, 3fa, 3ka, 3ae,

Tetrahedron
3
3af, and 3ak). In addition, these products were strongly blue
ACCEPTED MANUSCRIPT
emissive under UV light (Fig. 2, †ESI). The facts that the
resulting multiarylated triazolopyridines are characterized in
high fluorescence quantum yield and stokes shift indicate
that they have great potential as fluorescent probes in
medical applications (Fig. S7-S31, †ESI).
Table 2
Synthesis of triarylated [1,2,4] triazolo[1,5-a
]pyridinesa
Scheme 3 Controlled experiments catalyzed by Cu0.
Scheme 4 Controlled experiments catalyzed by CuI.
Scheme 5 Proposed Reaction Mechanism for The One-Step
Synthesis of [1,2,4]Triazolo[1,5-
Copper
a]pyridines Catalyzed by
3aa 3ba 3ca 3da 3ea 3fa 3ga 3ha 3ia 3ja 3ka 3ab 3ac
3ad 3ae 3af 3ah 3aj 3ak 3ma 3na 3al 3am 3an 3ao 3la

4
Tetrahedron
Fig. 2 Photographs of products (0.5 × 10-4 M) in MeCN
in medical chemistry and material science is ongoing.
ACCEPTED MANUSCRIPT
Further exploration of the detailed reaction development and
upon illumination with a UV lamp (
～365 nm).
application researsh is currently in progress.
A series of controlled experiments by the assistance of gas
chromatography analysis were carried out to gain some
4. Experimental section
4.1 General
insight into the mechanism (Scheme 3 and
4). When
TEMPO was added into the reaction system, no desired
products were observed. This result indicated the reaction
probably involved a free radical process. Furthermore,
gaseous hydrogen and methane were detected by GC from
All reactions were performed in oven-dried glassware.
Solvents were distilled prior to use. Analytical thin layer
chromatography (TLC) was performed on pre-coated silica
gel 60 F254 plates. Visualization on TLC was achieved by
the use of UV light (254 nm, 365 nm). Chromatographic
separations were performed using Biotage Flash Isolera
Prime RP-LC. IR spectra were recorded on a Nicolet
the reaction mixture (Scheme 3 and Scheme S3-S8
,
†ESI).14 Both Cu0 species and CuI species were detected
from reactions that catalyzed by Cu or CuCl by using X-ray
photoelectron spectroscopy (XPS
,
Fig. S3-S6, †ESI).15
1
AVATAR 370 spectrometer. All H, 19F and 13C NMR were
When ethyl-substituted azine 1l was applied to the reaction
system, which was derived from propiophenone and
hydrazine, the corresponding product 3la was obtained in
52% yield (Scheme 3) and the structure was confirmed by
single crystal X-ray diffraction analysis.16 Hydrogen,
methane, ethane, ethylene, propylene and isobutene were all
detected by GC from this reaction (Scheme 3, †ESI), which
implies the presence of ethyl radical during the whole
process. The in-situ generated hydrogen and ethyl radicals
could induce various free radical fragments and the
corresponding coupling products.17 When asymmetrical
substrate 1o was employed to the reaction with 2a, the product
recorded in CDCl3 or DMSO-d6 or CD2Cl2 at 25 ºC on a
Bruker AM500 spectrometers. 1H NMR chemical shifts
were determined relative to the signal of the residual
protonated solvent. 13C NMR chemical shifts were
1
determined relative to internal TMS at δ 0.0. Data for H,
13C and 19F NMR are recorded as follows: chemical shift (δ,
ppm), multiplicity (s = singlet, d = doublet, t = triplet, m =
multiplet, q = quartet, br = broad). High-resolution mass
data were recorded on a high–resolution mass spectrometer
in the MALDL mode. The absolute configurations of 3aa
and 3la were assigned by the X-ray analysis. UV spectra
were recorded on a UV-2501PC spectrometer. Fluorescence
3aa was obtained in 65% yield (Scheme 3). It was surprised to
find that H2 was detected only from the reaction of Cu0 and
spectra were recorded on
a
Shimadzu RF-5310
spectrometer. X-ray photoelectron spectra were obtained by
using Thermo Scientific Escalab 250Xi X-ray photoelectron
spectrometer. Gas qualitative appraisals were performed on
Ke Chuang GC9800(N)TH gas chromatograph and Agilent
HP6890 gas chromatograph.
2a. On the contrary, GC could not observe any hydrogen
from the reaction of CuCl with 2a (Scheme 4, †ESI).
As depicted in Scheme 5, we propose a radical
mechanism for this one-pot process based on the above
findings from the controlled experiments. Initially, an active
CuI–oxygen olefin-chelate complex
4
was formed from Cu0
4.2 General procedure for Synthsis of [1,2,4]Triazolo[1,5-
a]pyridines.To a dry 25 mL round-bottom flask was added azine
(0.5 mmol), propanedinitrile (1.0 mmol), Cu (0.1 mmol), dry
dimethylsulfoxide (10 mL) respectively. The reaction was stirred
at 100 oC for 8 h. The solvent was removed under reduced
pressure, and the residue was subject to column chromatograph
(petroleum ether/dichloromethane) to give the pure product.
and benzylidenemalononitrile in the presence of oxygen by
releasing hydrogen.18 However, hydride was produced
instead of hydrogen in the reaction using CuI catalysts.
Azine 1a is then attacked by 4, generating the intermediate 7
through the activation of C(sp3)-H bond forming a new C-C
bond.19 Meanwhile, CuI is transformed into Cu0 which then
reacts with 2a to regenerate complex 4 20
A 1,5-H shift
.
process occurs to give intermediate 8,21 which undergoes a
tandem addition/cyclization reaction affording 10, from
4.2.1
2,5,7-triphenyl-[1,2,4]triazolo[1,5-a]pyridine-8-
carbonitrile (3aa): white solid, 74% yield (0.1376 g), m.p. 201.6-
which two new C−N bonds are formed. The final product is
o
1
202.3 C; H NMR (500 MHz, CDCl3) δ 8.41 – 8.34 (m, 2H),
8.16 – 8.10 (m, 2H), 7.79 – 7.73 (m, 2H), 7.65 – 7.60 (m, 3H),
7.60 – 7.53 (m, 3H), 7.52 – 7.45 (m, 3H), 7.27 (s, 1H); 13C NMR
(125 MHz, CDCl3) δ 165.61, 152.48, 149.18, 143.80, 135.85,
131.34, 130.96, 130.68, 130.29, 129.97, 129.51, 129.21, 128.80,
128.68, 128.64, 127.88, 114.74, 114.64, 96.61; UV-vis (CH3CN)
λmax /nm 264, 334; FT-IR ν/cm-1 (KBr): 3053, 2218, 1607, 1526,
1493, 1441, 1385, 1322, 1290, 1224, 767, 730, 692; MALDI-
FTICR MS m/z Calcd for C25H16N4 M 372.1375, Found
372.1374.
generated from 10 by extruding a methyl radical forming
methane in the end.22
3. Conclusion
In conclusion, we have developed a novel copper-
catalyzed tandem radical cyclization of azines with
benzylidenemalononitriles, wherein one new C
−C bond and
two new C N bonds are constructed within one step. The
−
highly practical one-pot process provides a simple and
efficient route to multi-functionalized [1,2,4]triazolo[1,5-
4.2.2 7-phenyl-2,5-di-p-tolyl-[1,2,4]triazolo[1,5-a]pyridine-8-
carbonitrile (3ba): white solid, 72% yield (0.1440 g), m.p. 224.7-
225.1oC; 1H NMR (500 MHz, CDCl3) δ 8.26 (d, J = 8.2 Hz, 2H),
8.04 (d, J = 8.2 Hz, 2H), 7.77 – 7.73 (m, 2H), 7.61 – 7.52 (m,
3H), 7.42 (d, J = 8.0 Hz, 2H), 7.29 (d, J = 8.0 Hz, 2H), 7.23 (s,
1H), 2.50 (s, 3H), 2.43 (s, 3H); 13C NMR (125 MHz, CDCl3) δ
165.62, 152.50, 149.00, 143.84, 141.92, 140.87, 136.00, 130.18,
129.48, 129.44, 129.35, 129.16, 128.67, 128.13, 127.81, 127.24,
114.82, 114.19, 96.01, 21.64, 21.60; UV-vis (CH3CN) λmax /nm
268, 339; FT-IR ν/cm-1 (KBr): 3024, 2908, 2858, 2216, 1607,
1498, 1445, 1377, 1282, 1176, 1114, 822, 754, 694; MALDI-
a]pyridines from easily accessible raw materials. GC
analysis confirmed the by-products of gaseous hydrogen and
methane from the reaction. An appropriate mechanism was
proposed based on the controlled experiments and analytical
results. The resulting triarylated triazolopyridines have great
potential as fluorescent probes in medical applications due
to their strong blue fluorescence with large Strokes shifts
and high quantum yields. Further evaluation of this one-pot
method for the synthesis of even more complicated
heterocycles as well as the investigation of their applications

Tetrahedron
5
FTICR MS m/z Calcd for C27H20N4 [M+H]+ 401.1761, Found
401.1767.
ν/cm-1 (KBr): 3070, 2224, 1614, 1579, 1530, 1598, 4181, 1316,
ACCEPTED MANUSCRIPT
1227, 751, 698; MALDI-FTICR MS m/z Calcd for C25H14F2N4
M 408.1187, Found 408.1176.
4.2.3 2,5-bis(4-methoxyphenyl)-7-phenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ca): white solid, 76% yield (0.1642
g), m.p. 221.9-222.1 oC; 1H NMR (500 MHz, CDCl3) δ 8.27 (d, J
= 8.6 Hz, 2H), 8.12 (d, J = 8.7 Hz, 2H), 7.73 (d, J = 6.6 Hz, 2H),
7.62 – 7.49(m, 3H), 7.16 (s, 1H), 7.07 (d, J = 8.7 Hz, 2H), 6.96
(d, J = 8.6 Hz, 2H), 3.91 (s, 3H), 3.85 (s, 3H); 13C NMR (125
MHz, CDCl3) δ 165.21, 161.93, 161.58, 152.56, 148.81, 143.32,
136.05, 131.20, 130.08, 129.34, 129.09, 128.64, 123.11, 122.59,
114.95, 114.11, 113.94, 113.50, 95.17, 55.53, 55.33; UV-vis
(CH3CN) λmax /nm 274, 350; FT-IR ν/cm-1 (KBr): 3050, 3004,
2220, 1606, 1501, 1450, 1295, 1250, 1171, 1117, 1014, 834, 763,
4.2.7 7-phenyl-2,5-di-o-tolyl-[1,2,4]triazolo[1,5-a]pyridine-8-
carbonitrile (3ga): white solid, 62% yield (0.1240 g), m.p. 182.7-
183.1oC; 1H NMR (500 MHz, CDCl3) δ8.19 – 8.15 (m, 1H), 7.80
– 7.76(m, 2H), 7.61 – 7.55 (m, 3H), 7.52 – 7.46 (m, 2H), 7.42 (d,
J = 7.7 Hz, 1H), 7.40 – 7.35 (m, 1H), 7.33 (m, 1H), 7.29 (m, 2H),
7.15 (s, 1H), 2.64 (s, 3H), 2.29 (s, 3H); 13C NMR (125 MHz,
CDCl3) δ 166.80, 151.06, 148.93, 144.70, 138.20, 137.54,
135.76, 131.31, 131.23, 130.72, 130.68, 130.61, 130.31, 129.96,
129.76, 129.21, 129.17, 128.77, 126.04, 125.84, 115.70, 114.57,
96.94, 21.94, 20.11; UV-vis (CH3CN) λmax /nm 260, 325; FT-IR
ν/cm-1 (KBr); 3060, 2958, 2856, 2221, 1616, 1532, 1596, 1451,
1309, 1286, 768, 732, 699; MALDI-FTICR MS m/z Calcd for
C27H20N4 M 400.1688, Found 400.1679.
699 ; MALDI-FTICR MS m/z Calcd for C27H20N4O2
432.1586, Found 432.1589.
M
4.2.4
2,5-bis(4-fluorophenyl)-7-phenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3da): white solid, 67% yield (0.1367
4.2.8
2,5-bis(2-chlorophenyl)-7-phenyl-[1,2,4]triazolo[1,5-
o
g), m.p. 243.4-243.8 C; 1H NMR (500 MHz, CDCl3) δ 8.36 (dd,
a]pyridine-8-carbonitrile (3ha): white solid, 32% yield (0.0706
g), m.p. 166.5-167.0 oC; 1H NMR (500 MHz, CDCl3) δ 8.04 (d, J
= 6.6 Hz, 1H), 7.79 (d, J = 6.3 Hz, 2H), 7.69 (d, J = 7.2 Hz, 1H),
7.65 – 7.55 (m, 4H), 7.54 (t, J = 7.7 Hz, 1H), 7.49 (m, 2H), 7.38
(m, 2H), 7.31 (s, 1H); 13C NMR (125 MHz, CDCl3) δ 164.33,
151.07, 149.08, 141.40, 135.52, 133.81, 133.68, 132.49, 132.07,
131.48, 131.05, 130.72, 130.48, 130.42, 130.12, 129.27, 128.80,
127.05, 126.73, 116.90, 114.23, 97.96; UV-vis (CH3CN) λmax
/nm 257, 321; FT-IR ν/cm-1 (KBr): 3060, 2226, 1608, 1524,
1425, 1316, 1042, 746, 695; MALDI-FTICR MS m/z Calcd for
C25H14Cl2N4 M 440.0596, Found 440.0585.
J = 8.5, 5.5 Hz, 2H), 8.14 (dd, J = 8.7, 5.3 Hz, 2H), 7.80 – 7.71
(m, 2H), 7.65 – 7.54 (m, 3H), 7.31 (t, J = 8.5 Hz, 2H), 7.25 (s,
1H), 7.18 (t, J = 8.7 Hz, 2H); 19F NMR (470 MHz, DMSO-d6) δ -
108.49, -109.74; 13C NMR (125 MHz, DMSO-d6) δ164.15 (d, JFC
= -240.7 Hz), 164.12 (d, JFC = -250.1 Hz), 163.61, 152.56,
149.68, 142.85, 135.95, 133.01 (d, J FC= 8.9 Hz), 130.79, 130.06
(d, J FC= 8.9 Hz), 129.49, 129.48, 127.50 (d, JFC = 3.3 Hz),
126.68 (d, JFC = 2.7 Hz), 116.62 (d, JFC = 21.9 Hz), 116.16 (d,
JFC = 22.0 Hz), 115.78, 115.41, 96.02; UV-vis (CH3CN) λmax /nm
264, 335; FT-IR ν/cm-1 (KBr): 3075, 2227, 1606, 1501, 1450,
1232, 1158, 840, 760, 695; MALDI-FTICR MS m/z Calcd for
C25H14F2N4 [M+H]+ 409.1259, Found 409.1259.
4.2.9
2,5-bis(3-fluorophenyl)-7-phenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ia): white solid, 54% yield (0.1102
o
1
4.2.5
7-phenyl-2,5-bis(4-(trifluoromethyl)phenyl)-
g), m.p. 232.6-232.7 C; H NMR (500 MHz, CDCl3) δ 8.19 –
8.13 (m, 1H), 8.05 (ddd, J = 9.7, 2.5, 1.5 Hz, 1H), 7.93 – 7.85 (m,
2H), 7.79 – 7.73 (m, 2H), 7.64 – 7.54 (m, 4H), 7.47 (m, 1H), 7.34
(tdd, J = 8.4, 2.5, 0.8 Hz, 1H), 7.31 (s, 1H), 7.22 – 7.15 (m, 1H);
19F NMR (470 MHz, DMSO-d6) δ -112.11, -113.23; 13C NMR
[1,2,4]triazolo[1,5-a]pyridine-8-carbonitrile (3ea): white solid,
54% yield (0.1372 g), m.p. 230.6-231.0oC; H NMR (500 MHz,
1
CDCl3) δ 8.47 (d, J = 8.1 Hz, 2H), 8.24 (d, J = 8.2 Hz, 2H), 7.90
(d, J = 8.2 Hz, 2H), 7.80 – 7.72 (m, 4H), 7.64 – 7.56 (m, 3H),
7.35 (s, 1H); 19F NMR (470 MHz, DMSO-d6) δ -62.80, -62.99;
13C NMR (125 MHz, CDCl3) δ 163.38, 151.36, 148.57, 141.24,
134.28, 133.04 (d, JFC = 1.3 Hz), 132.10 (q, JFC= 33.0 Hz),
132.04 (d, JFC = 1.2 Hz), 131.44 (q, JFC = 32.5 Hz), 129.63,
128.93, 128.90, 128.33, 127.61, 127.10, 124.83 (q, JFC = 3.8 Hz),
124.63 (q, JFC = 3.7 Hz), 122.90 (q, JFC = -272.4 Hz), 122.56 (q,
JFC = -272.6 Hz), 114.64, 113.13, 96.82; UV-vis (CH3CN) λmax
/nm 263, 331; FT-IR ν/cm-1 (KBr): 3460, 2224, 1617, 1533,
1446, 1326, 1247, 1171, 1114, 1063, 1010, 846, 773, 700;
MALDI-FTICR MS m/z Calcd for C27H14F6N4 M 508.1123,
Found 508.1125.
(125 MHz, CD2Cl2) δ 164.37 (d, JFC = 3.1 Hz), 163.05 (d, JFC
=
245.3 Hz), 162.54 (d, JFC = 246.7 Hz), 152.47, 149.55, 142.39 (d,
JFC = 2.6 Hz), 135.69, 132.69 (d, JFC = 8.5 Hz), 132.18 (d, JFC=
8.5 Hz), 130.61 (d, JFC = 8.3 Hz), 130.52 (d, JFC = 8.2 Hz),
130.46, 129.19, 128.71, 125.37 (d, JFC = 3.1 Hz), 123.49 (d, JFC
=
3.0 Hz), 118.31 (d, JFC = 21.1 Hz), 117.60 (d, JFC = 21.2 Hz),
116.63 (d, JFC = 24.2 Hz), 115.48, 114.45 (d, JFC = 23.5 Hz),
114.38, 97.30; UV-vis (CH3CN) λmax /nm 264, 332; FT-IR ν/cm-1
(KBr); 3062, 2226, 1613, 1583, 1527, 1468, 1431, 1377, 1318,
1240, 1205, 865, 791, 756, 689; MALDI-FTICR MS m/z Calcd
for C25H14F2N4 M 408.1187, Found 408.1177.
4.2.6
2,5-bis(2-fluorophenyl)-7-phenyl-[1,2,4]triazolo[1,5-
4.2.10 2,5-bis(3-methoxyphenyl)-7-phenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ja): white solid, 56% yield (0.1210
a]pyridine-8-carbonitrile (3fa): white solid, 55% yield (0.1122
g), m.p. 226.6-227.0 oC;1H NMR (500 MHz, CDCl3) δ 8.32 (td, J
= 7.6, 1.7 Hz, 1H), 7.98 (td, J = 7.6, 1.7 Hz, 1H), 7.80 – 7.74 (m,
2H), 7.64 – 7.54 (m, 4H), 7.49 – 7.43 (m, 1H), 7.39 (td, J = 7.7,
1.1 Hz, 1H), 7.35 (d, J = 1.4 Hz, 1H), 7.34 – 7.30 (m, 1H), 7.28
(td, J = 7.7, 1.1 Hz, 1H), 7.23 – 7.17 (m, 1H); 19F NMR (470
MHz, DMSO-d6) δ -110.59, -110.71; 13C NMR (125 MHz,
CDCl3) δ 162.25 (d, JFC = 5.0 Hz), 160.94 (d, JFC = 257.0 Hz),
160.05 (d, JFC = 253.4 Hz), 151.44, 149.11, 138.58 (d, JFC = 1.2
Hz), 135.57, 133.15 (d, JFC = 8.7 Hz), 132.11 (d, JFC = 8.4 Hz),
131.46 (d, JFC = 14.6 Hz), 131.45 (d, JFC = 13.9 Hz), 130.43,
129.25, 128.76, 124.36 (d, JFC = 21.0 Hz), 124.33 (d, JFC = 21.1
Hz), 118.94 (d, JFC = 13.2 Hz), 118.21 (d, JFC = 11.2 Hz), 116.81
(d, JFC = 3.9 Hz), 116.63 (d, JFC = 21.4 Hz), 116.58 (d, JFC = 21.6
Hz), 114.34, 97.59; UV-vis (CH3CN) λmax /nm 258, 327; FT-IR
o
1
g), m.p. 185.1-185.2 C; H NMR (500 MHz, CDCl3) δ 7.99 –
7.94 (m, 1H), 7.91 (dd, J = 2.5, 1.4 Hz, 1H), 7.79 – 7.74 (m, 2H),
7.74 – 7.70 (m, 1H), 7.67 – 7.62 (m, 1H), 7.62 – 7.54 (m, 3H),
7.51 (t, J = 8.0 Hz, 1H), 7.39 (t, J = 7.9 Hz, 1H), 7.28 (s, 1H),
7.15 (m, 1H), 7.03 (m, 1H), 3.92 (s, 3H), 3.92 (s, 3H); 13C NMR
(125 MHz, CDCl3) δ 165.46, 159.85, 159.64, 152.45, 149.16,
143.59, 135.83, 132.06, 131.28, 130.31, 129.89, 129.74, 129.22,
128.69, 121.80, 120.34, 117.17, 117.12, 114.97, 114.81, 114.63,
112.48, 96.65, 55.57, 55.49; UV-vis (CH3CN) λmax /nm 263, 338;
FT-IR ν/cm-1 (KBr): 3050, 3004, 2936, 2840, 2220, 1610, 1501,
1450, 1384, 1495, 1250, 1171, 1117, 1024, 834, 763, 699;
MALDI-FTICR MS m/z Calcd for C27H20N4O2 M 432.1586,
Found 432.1577.

6
Tetrahedron
4.2.11 2,5-bis(3-bromophenyl)-7-phenyl-[1,2,4]triazolo[1,5-
2224, 1606, 1520, 1443, 1380, 1300, 1231, 1160, 1111, 841, 765,
ACCEPTED MANUSCRIPT
a]pyridine-8-carbonitrile (3ka): white solid, 55% yield (0.1458
g), m.p. 257.5-257.6 oC; 1H NMR (500 MHz, CDCl3) δ 8.51 (t, J
= 1.7 Hz, 1H), 8.32 – 8.28 (m, 1H), 8.19 (t, J = 1.8 Hz, 1H), 8.08
(ddd, J = 7.9, 1.7, 1.0 Hz, 1H), 7.79 – 7.74 (m, 3H), 7.64 – 7.57
(m, 4H), 7.52 (t, J = 8.0 Hz, 1H), 7.38 (t, J = 7.9 Hz, 1H), 7.29 (s,
1H); 13C NMR (125 MHz, CD2Cl2) δ 164.12, 152.44, 149.61,
142.24, 135.66, 134.26, 133.69, 132.72, 132.22, 132.04, 130.48,
130.45, 130.39, 129.20, 128.71, 128.25, 126.35, 122.80, 122.64,
115.54, 114.36, 97.39; UV-vis (CH3CN) λmax /nm 265, 333; FT-
IR ν/cm-1 (KBr): 3069, 2229, 1617, 1559, 1520, 1460, 1323,
1290, 762, 689, 597, 513; MALDI-FTICR MS m/z Calcd for
C25H14Br2N4 M 527.9585, Found 527.9569.
723, 688; MALDI-FTICR MS m/z Calcd for C25H15FN4
390.1283, Found 390.1285.
M
4.2.16
7-(4-bromophenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3af): white solid, 66% yield (0.1488
o
1
g), m.p. 236.1-236.2 C; H NMR (500 MHz, CDCl3) δ 8.39 –
8.33 (m, 2H), 8.15 – 8.08 (m, 2H), 7.76 – 7.69 (m, 2H), 7.67 –
7.60 (m, 5H), 7.53 – 7.46 (m, 3H), 7.22 (s, 1H); 13C NMR (125
MHz, CDCl3) δ 165.72, 152.33, 147.79, 144.02, 134.65, 132.46,
131.46, 130.77, 130.75, 130.19, 129.82, 129.49, 128.82, 128.64,
127.86, 125.02, 114.42, 114.26, 96.47; UV-vis (CH3CN) λmax
/nm 268, 336; FT-IR ν/cm-1 (KBr): 3078, 2223, 1612, 1527,
1484, 1438, 1388, 1289, 1224, 1065, 830, 766, 721, 688;
MALDI-FTICR MS m/z Calcd for C25H15BrN4 M 450.0480,
Found 450.0486.
4.2.12 2,5-diphenyl-7-(p-tolyl)-[1,2,4]triazolo[1,5-a]pyridine-
8-carbonitrile (3ab): white solid, 67% yield (0.1293 g), m.p.
o
1
217.0-217.6 C; H NMR (500 MHz, CDCl3) δ 8.38 – 8.32 (m,
2H), 8.11 (dt, J = 8.1, 3.4 Hz, 2H), 7.66 (d, J = 8.1 Hz, 2H), 7.63
– 7.57 (m, 3H), 7.51 – 7.44 (m, 3H), 7.38 (d, J = 7.9 Hz, 2H),
7.25 (s, 1H), 2.46 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 165.47,
152.53, 149.21, 143.66, 140.71, 132.94, 131.26, 131.01, 130.61,
130.01, 129.90, 129.49, 128.76, 128.61, 128.58, 127.85, 114.82,
114.70, 96.27, 21.42; UV-vis (CH3CN) λmax /nm 267, 335; FT-IR
ν/cm-1 (KBr):3067, 3032, 2225, 1611, 1527, 1440, 1286, 1228,
1027, 831, 767, 723, 686; MALDI-FTICR MS m/z Calcd for
C26H18N4 M 386.1531, Found 386.1536.
4.2.17
7-(4-nitrophenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ag): yellow solid, 54% yield (0.1126
g), m.p. 296.8-297.1oC; 1H NMR (500 MHz, CD2Cl2) δ 8.45 (d, J
= 8.6 Hz, 2H), 8.40 – 8.33 (m, 2H), 8.18 – 8.11 (m, 2H), 7.96 (d,
J = 8.6 Hz, 2H), 7.66 (d, J = 5.4 Hz, 3H), 7.59 – 7.49 (m, 3H),
7.30 (s, 1H); 13C NMR (125 MHz, CD2Cl2) δ 165.84, 152.25,
148.81, 146.65, 144.49, 142.03, 131.62, 130.94, 130.70, 129.99,
129.84, 129.56, 128.86, 128.81, 127.75, 124.26, 114.31, 114.06,
97.10; UV-vis (CH3CN) λmax /nm 262, 339; FT-IR ν/cm-1 (KBr):
3062, 2227, 1605, 1523, 1440, 1343, 1303, 1209, 1109, 858, 748,
699; MALDI-FTICR MS m/z Calcd for C25H15N5O2 [M+H]+
418.1299, Found 418.1300.
4.2.13 7-(4-methoxyphenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ac): colourless solid, 59% yield
o
1
(0.1186 g), m.p. 251.0-251.3 C; H NMR (500 MHz, CDCl3) δ
8.37 (dt, J = 8.9, 2.8 Hz, 2H), 8.15 – 8.08 (m, 2H), 7.77 – 7.71
(m, 2H), 7.65 – 7.58 (m, 3H), 7.52 – 7.46 (m, 3H), 7.25 (s, 1H),
7.12 – 7.07 (m, 2H), 3.91 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
165.50, 161.38, 152.66, 148.90, 143.65, 131.28, 131.09, 130.64,
130.24, 130.07, 129.52, 128.80, 128.65, 128.05, 127.89, 115.04,
114.71, 114.64, 95.87, 55.55; UV-vis (CH3CN) λmax /nm 262,
340; FT-IR ν/cm-1 (KBr):3069, 2988, 2933, 2841, 2224, 1604,
1523, 1487, 1434, 1380, 1291, 1249, 1176, 1116, 1016, 837, 771,
724, 703, 686; MALDI-FTICR MS m/z Calcd for C26H18N4O
[M+H]+ 403.1553, Found 403.1554.
4.2.18 7-(2-methoxyphenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ah): white solid, 70% yield (0.1407
1
g), m.p. 201.4-201.5 oC; H NMR (500 MHz, CDCl3) δ 8.38 (dd,
J = 6.5, 3.0 Hz, 2H), 8.12 (dd, J = 6.6, 2.9 Hz, 2H), 7.64 – 7.58
(m, 3H), 7.55 – 7.50 (m, 1H), 7.49 (dd, J = 4.8, 1.6 Hz, 3H), 7.45
(dd, J = 7.5, 1.6 Hz, 1H), 7.25 (s, 1H), 7.17 – 7.07 (m, 2H), 3.91
(s, 3H); 13C NMR (125 MHz, CDCl3) δ 165.31, 156.41, 152.20,
146.76, 143.21, 131.73, 131.16, 131.12, 130.60, 130.56, 130.13,
129.53, 128.72, 128.62, 127.87, 124.90, 121.08, 116.04, 114.52,
111.68, 99.06, 55.62; UV-vis (CH3CN) λmax /nm 262, 336; FT-IR
ν/cm-1 (KBr): 3041, 2921, 2845, 2228, 1613, 1524, 1445, 1296,
1255, 1018, 747, 686; MALDI-FTICR MS m/z Calcd for
C26H18N4O [M+H]+ 403.1553, Found 403.1548.
4.2.14
7-(4-ethoxyphenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ad): white solid, 62% yield (0.1290
1
g), m.p. 226.1-226.6 oC; H NMR (500 MHz, CDCl3) δ 8.39 –
8.33 (m, 2H), 8.14 – 8.08 (m, 2H), 7.75 – 7.70 (m, 2H), 7.64 –
7.59 (m, 3H), 7.51 – 7.45 (m, 3H), 7.24 (s, 1H), 7.09 – 7.04 (m,
2H), 4.13 (q, J = 7.0 Hz, 2H), 1.47 (t, J = 7.0 Hz, 3H); 13C NMR
(125 MHz, CDCl3) δ 165.41, 160.76, 152.63, 148.89, 143.57,
131.23, 131.06, 130.58, 130.19, 130.05, 129.49, 128.75, 128.61,
127.84, 127.78, 115.12, 115.05, 114.63, 95.70, 63.78, 14.75; UV-
vis (CH3CN) λmax /nm 262, 341; FT-IR ν/cm-1 (KBr): 3071, 3034,
2980, 2925, 2881, 2228, 1604, 1522, 1484, 1435, 1833, 1294,
1247, 1171, 1037, 841, 772, 724, 703, 687; MALDI-FTICR MS
m/z Calcd for C27H20N4O M 416.1634, Found 416.1631.
4.2.19
7-(2-nitrophenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ai): yellow solid, 57% yield (0.1188
g), m.p. 200.0-200.2oC; H NMR (500 MHz, CDCl3) δ 8.41 –
1
8.35 (m, 2H), 8.31 (dd, J = 8.3, 1.1 Hz, 1H), 8.13 – 8.06 (m, 2H),
7.85 (td, J = 7.6, 1.3 Hz, 1H), 7.79 – 7.73 (m, 1H), 7.64 – 7.62
(m, 1H), 7.61 (m, 2H), 7.60 – 7.57 (m, 1H), 7.53 – 7.47 (m, 3H),
7.06 (s, 1H); 13C NMR (125 MHz, CDCl3) δ 165.84, 151.70,
147.49, 146.60, 144.01, 134.03, 131.75, 131.55, 131.38, 131.10,
130.83, 130.58, 129.82, 129.62, 128.81, 128.70, 127.94, 125.61,
113.73, 113.51, 98.02; UV-vis (CH3CN) λmax /nm 255, 332; FT-
IR ν/cm-1 (KBr): 3054, 2224, 1613, 1522, 1440, 1341, 1297,
1198, 1025, 754, 707, 691; MALDI-FTICR MS m/z Calcd for
C25H15N5O2 [M+H]+ 418.1299, Found 418.1292.
4.2.15
7-(4-fluorophenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ae): white solid, 71% yield (0.1385
1
g), m.p. 237.2-237.8oC; H NMR (500 MHz, CDCl3) δ 8.41 –
8.33 (m, 2H), 8.12 (dd, J = 6.5, 3.2 Hz, 2H), 7.80 – 7.71 (m, 2H),
7.68 – 7.58 (m, 3H), 7.53 – 7.46 (m, 3H), 7.29 (d, J = 8.5 Hz,
4.2.20 2,5-diphenyl-7-(m-tolyl)-[1,2,4]triazolo[1,5-a]pyridine-
8-carbonitrile (3aj): light yellow solid, 63% yield (0.1216 g),
o
1
2H), 7.23 (s, 1H); 19F NMR (470 MHz, DMSO-d6) δ -109.71; 13
C
m.p. 202.6-202.8 C; H NMR (500 MHz, CDCl3) δ 8.40 – 8.35
(m, 2H), 8.16 – 8.10 (m, 2H), 7.65 – 7.60 (m, 3H), 7.57 (d, J =
8.2 Hz, 1H), 7.55 (s, 1H), 7.51 – 7.44 (m, 4H), 7.37 (d, J = 7.6
Hz, 1H), 7.27 (s, 1H), 2.49 (s, 3H); 13C NMR (125 MHz, CDCl3)
δ 165.56, 152.49, 149.37, 143.69, 139.07, 135.83, 131.30,
131.04, 131.00, 130.65, 130.01, 129.51, 129.21, 129.10, 128.79,
NMR (125 MHz, CDCl3) δ 165.72, 163.94 (d, JFC = -251.8 Hz),
152.40, 148.04, 143.94, 131.91 (d, JFC = 3.4 Hz), 131.44, 130.85,
130.76 (d, JFC = 8.6 Hz), 130.75, 129.89, 129.51, 128.84,
128.67, 127.89, 116.45 (d, JFC = 22.0 Hz), 114.56, 114.52, 96.56;
UV-vis (CH3CN) λmax /nm 265, 335; FT-IR ν/cm-1 (KBr): 3068,

Tetrahedron
ACCEPTED MANUSCRIPT
7
128.63, 127.88, 125.83, 114.78, 114.65, 96.56, 21.50; UV-vis
8.04 (d, J = 3.7 Hz, 1H), 7.68 – 7.56 (m, 4H), 7.51 – 7.44 (m,
(CH3CN) λmax /nm 265, 334; FT-IR ν/cm-1 (KBr): 3065, 2916,
2849, 2216, 1607, 1523, 1492, 1438, 1332, 1293, 1258, 1027,
789, 764, 722, 691; MALDI-FTICR MS m/z Calcd for C26H18N4
[M+H]+ 387.1604, Found 387.1604.
3H), 7.34 (s, 1H), 7.27 (d, J = 5.0 Hz, 1H); 13C NMR (125 MHz,
CDCl3) δ 165.62, 152.70, 143.76, 140.83, 137.26, 131.41,
130.80, 130.69, 129.99, 129.92, 129.89, 129.54, 129.01, 128.83,
128.64, 127.85, 115.12, 113.70, 93.89; UV-vis (CH3CN) λmax
/nm 273, 351; FT-IR ν/cm-1 (KBr): 3100, 3057, 2217, 1611,
1529, 1419, 1297, 1242, 1065, 843, 764, 704; MALDI-FTICR
MS m/z Calcd for C23H14N4S [M+H]+ 379.1017, Found
379.1012.
4.2.21
7-(3-bromophenyl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ak): white solid, 63% yield (0.1421
o
1
g), m.p. 205.7-205.8 C; H NMR (500 MHz, CDCl3) δ 8.40 –
8.34 (m, 2H), 8.13 (dd, J = 6.5, 3.2 Hz, 2H), 7.84 (t, J = 1.8 Hz,
1H), 7.75 – 7.71 (m, 1H), 7.70 (ddd, J = 8.0, 1.8, 0.9 Hz, 1H),
7.66 – 7.60 (m, 3H), 7.52 – 7.48 (m, 3H), 7.47 (t, J = 8.0 Hz,
1H), 7.23 (s, 1H); 13C NMR (125 MHz, CDCl3) δ 165.83, 152.30,
147.35, 144.11, 137.78, 133.27, 131.52, 131.45, 130.80, 130.75,
130.71, 129.83, 129.53, 128.86, 128.68, 127.92, 127.44, 123.23,
114.34, 114.22, 96.83; UV-vis (CH3CN) λmax /nm 264, 335; FT-
IR ν/cm-1 (KBr): 3046, 2219, 1609, 1571, 1524, 1442, 1371,
1331, 1291, 1072, 791, 758, 686; MALDI-FTICR MS m/z Calcd
for C25H15BrN4 [M+H]+ 451.0553, Found 451.0553.
4.2.26
2,5-diphenyl-7-(pyridin-3-yl)-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3am): white solid, 70% yield (0.1304
o
1
g), m.p. 247.5-247.6 C; H NMR (500 MHz, CDCl3) δ 8.96 (s,
1H), 8.81 (d, J = 3.9 Hz, 1H), 8.36 (dd, J = 6.5, 2.9 Hz, 2H), 8.18
– 8.07 (m, 3H), 7.63 (d, J = 3.5 Hz, 3H), 7.54 (dd, J = 7.7, 4.9
Hz, 1H), 7.51 – 7.44 (m, 3H), 7.25 (s, 1H); 13C NMR (125 MHz,
CDCl3) δ 165.92, 152.31, 151.20, 149.07, 145.52, 144.40,
136.16, 131.99, 131.64, 130.89, 130.66, 129.75, 129.55, 128.92,
128.72, 127.94, 123.78, 114.17, 114.12, 97.13; UV-vis (CH3CN)
λmax /nm 262, 336; FT-IR ν/cm-1 (KBr): 3042, 2225, 1611, 1524,
1492, 1442, 1332, 1292, 1200, 1024, 761, 717, 683; MALDI-
FTICR MS m/z Calcd for C24H15N5 [M+H]+ 374.1406, Found
374.1400.
4.2.22 6-methyl-2,5,7-triphenyl-[1,2,4]triazolo[1,5-a]pyridine-
8-carbonitrile (3la): white solid, 52% yield (0.1004 g), m.p.
o
1
290.5-290.6 C; H NMR (500 MHz, CDCl3) δ 8.29 – 8.21 (m,
2H), 7.67 – 7.50 (m, 8H), 7.46 – 7.39 (m, 5H), 2.03 (s, 3H); 13C
NMR (125 MHz, CDCl3) δ 164.94, 151.74, 149.81, 142.53,
135.92, 131.02, 130.38, 130.17, 130.12, 129.79, 129.47, 129.05,
128.80, 128.50, 128.48, 127.79, 120.98, 114.12, 99.71, 17.58;
UV-vis (CH3CN) λmax /nm 257, 326; FT-IR ν/cm-1 (KBr): 3056,
2963, 2852, 2223, 1607, 1519, 1481, 1439, 1327, 1261, 1011,
756, 745, 696; MALDI-FTICR MS m/z Calcd for C26H14N4 M
386.1531, Found 386.1535.
4.2.27
7-(furan-2-yl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3an): yellowish-green solid, 49%
yield (0.0887 g), m.p. 259.2-259.5 oC; 1H NMR (500 MHz,
CDCl3) δ 8.34 (dd, J = 6.5, 2.9 Hz, 2H), 8.13 (dd, J = 6.4, 2.9 Hz,
2H), 7.75 – 7.65 (m, 2H), 7.64 (s, 1H), 7.63 – 7.54 (m, 3H), 7.50
– 7.44 (m, 3H), 6.69 (dd, J = 3.4, 1.6 Hz, 1H); 13C NMR (125
MHz, CDCl3) δ 165.53, 152.55, 148.00, 145.23, 144.00, 135.97,
131.31, 131.03, 130.64, 130.54, 129.93, 129.53, 128.78, 128.63,
127.84, 115.10, 114.67, 113.36, 110.12; UV-vis (CH3CN) λmax
/nm 277, 354; FT-IR ν/cm-1 (KBr): 3053, 2218, 1615, 1533,
1479, 1442, 1293, 1212, 1027, 760, 719; MALDI-FTICR MS
m/z Calcd for C23H14N4O [M+H]+ 363.1246, Found 363.1241.
4.2.23
2,5-di(naphthalen-2-yl)-7-phenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ma): yellowish-green solid, 72%
yield (0.1699 g), m.p. 271.2-271.3 oC; 1H NMR (500 MHz,
CDCl3) δ 8.96 (s, 1H), 8.70 (s, 1H), 8.44 (d, J = 8.7 Hz, 1H), 8.21
(d, J = 8.6 Hz, 1H), 8.10 (d, J = 8.7 Hz, 1H), 8.07 – 7.97 (m, 3H),
7.95 (d, J = 8.6 Hz, 1H), 7.88 (d, J = 5.4 Hz, 1H), 7.82 (d, J = 6.7
Hz, 2H), 7.71 – 7.57 (m, 5H), 7.57 – 7.49 (m, 2H); 13C NMR
(125 MHz, CDCl3) δ 165.79, 152.70, 149.32, 143.95, 135.94,
134.61, 134.47, 133.26, 132.92, 130.36, 130.27, 129.28, 129.04,
128.99, 128.76, 128.55, 128.40, 128.36, 128.19, 128.15, 127.91,
127.84, 127.33, 127.17, 127.13, 126.51, 125.74, 124.74, 115.09,
114.76, 96.61; UV-vis (CH3CN) λmax /nm 250, 346; FT-IR ν/cm-1
(KBr): 3047, 2227, 1612, 1518, 1431, 1347, 1278, 1133, 855,
815, 760, 698; MALDI-FTICR MS m/z Calcd for C33H20N4
[M+H]+ 473.1766, Found 473.1758.
4.2.28
7-(naphthalen-2-yl)-2,5-diphenyl-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3ao): white solid, 55% yield (0.1161
g), m.p. 283.7-283.9 C;1H NMR (500 MHz, CDCl3) δ 8.39 (dd,
o
J = 5.9, 2.4 Hz, 2H), 8.25 (s, 1H), 8.19 – 8.12 (m, 2H), 8.04 (d, J
= 8.5 Hz, 1H), 7.99 (d, J = 8.3 Hz, 1H), 7.94 (d, J = 7.1 Hz, 1H),
7.86 – 7.81 (m, 1H), 7.63 (dd, J = 4.0, 2.4 Hz, 3H), 7.62 – 7.57
(m, 2H), 7.53 – 7.47 (m, 3H), 7.38 (s, 1H); 13C NMR (125 MHz,
CDCl3) δ 165.70, 152.59, 149.19, 143.85, 133.80, 133.15,
133.09, 131.39, 131.03, 130.72, 130.02, 129.57, 129.20, 128.87,
128.85, 128.74, 128.69, 127.94, 127.87, 127.73, 127.13, 125.45,
114.95, 114.75, 96.82; UV-vis (CH3CN) λmax /nm 266, 339; FT-
IR ν/cm-1 (KBr): 3054, 2226, 1608, 1525, 1434, 1293, 1207,
1024, 821, 762, 715, 694; MALDI-FTICR MS m/z Calcd for
C29H18N4 [M+H]+ 423.1610, Found 423.1604.
4.2.24
7-phenyl-2,5-di(thiophen-2-yl)-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3na): yellowish-green solid, 50%
yield (0.0960 g), m.p. 236.2-236.3oC; H NMR (500 MHz,
1
CDCl3) δ 8.42 (d, J = 3.7 Hz, 1H), 8.07 (d, J = 3.3 Hz, 1H), 7.80
– 7.70 (m, 3H), 7.59 (m, 3H), 7.53 (d, J = 4.2 Hz, 2H), 7.34 –
7.29 (m, 1H), 7.23 – 7.17 (m, 1H); 13C NMR (125 MHz, CDCl3)
δ 161.49, 152.30, 149.08, 137.26, 135.93, 132.68, 132.57,
132.00, 131.81, 130.29, 129.44, 129.24, 129.09, 128.69, 128.28,
128.13, 114.64, 111.51, 94.71; UV-vis (CH3CN) λmax /nm 283,
367; FT-IR ν/cm-1 (KBr): 3086, 2213, 1604, 1557, 1519, 1468,
1397, 1304, 1211, 1091, 1048, 845, 764, 698; MALDI-FTICR
MS m/z Calcd for C21H12N4S2 [M+H]+ 385.0582, Found
385.0574.
Acknowledgments
We gratefully acknowledge the National Nature Science
Foundation of China (No. 21272151) for financial support.
& These authors contributed equally to this work and should
be considered co-first authors.
Supplementary Material
Supplementary data associated with this article can be found in
the online version, at
4.2.25
2,5-diphenyl-7-(thiophen-2-yl)-[1,2,4]triazolo[1,5-
a]pyridine-8-carbonitrile (3al): yellowish-green solid, 42% yield
(0.0794 g), m.p. 233.8-233.9 C; H NMR (500 MHz, CDCl3) δ
8.35 (dd, J = 6.5, 2.8 Hz, 2H), 8.11 (dd, J = 6.5, 2.8 Hz, 2H),
o
1

8
Tetrahedron
ACCEPTED MANUSCRIPT
Bolas, C. G.; Cueni, P.; Fantasia, S.; Gaeng, Ni.; Trita, A. S. J.
Org. Chem. 2015, 80, 1249−1257.
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Tetrahedron
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9
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