Reagent/Substituent Switching Approach for the Synthesis of Substituted 1,3,4-Oxadiazole/1,3,4-Oxadiazoline and 1,2,4-Triazole Derivatives from N-Substituted Hydrazides

Article abstract of DOI:10.1002/adsc.201600274

A metal-free method for the synthesis of substituted 1,3,4-oxadiazole/1,3,4-oxadiazoline and 1,2,4-triazole derivatives from a common starting material via reagent/substituent switching is reported. In the presence of 2-fluoropyridine/triflic anhydride, 1,3,4-oxadiazole derivatives were exclusively formed from N′-tert-butylhydrazides and 1,3,4-oxadiazoline derivatives were produced from N-phenylhydrazides. On the other hand, when using pyridine/triflic anhydride, salts of 1,2,4-triazoles were the sole products. (Figure presented.).

Full text of DOI:10.1002/adsc.201600274

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DOI: 10.1002/adsc.201600274
Reagent/Substituent Switching Approach for the Synthesis of
Substituted 1,3,4-Oxadiazole/1,3,4-Oxadiazoline and 1,2,4-Triazole
Derivatives from N-Substituted Hydrazides
a
a
a
a
Trimurtulu Kotipalli, Veerababurao Kavala, Ashok Konala, Donala Janreddy,
a
a,
Chu-Wei Kuo, and Ching-Fa Yao *
Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei, Taiwan 116, R.O.C.
a
E-mail: cheyaocf@ntnu.edu.tw
Received: March 10, 2016; Revised: May 25, 2016; Published online: && &&, 0000
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201600274.
Abstract: A metal-free method for the synthesis of hydrazides. On the other hand, when using pyridine/
substituted 1,3,4-oxadiazole/1,3,4-oxadiazoline and triflic anhydride, salts of 1,2,4-triazoles were the sole
1,2,4-triazole derivatives from a common starting products.
material via reagent/substituent switching is report-
ed. In the presence of 2-fluoropyridine/triflic anhy-
dride, 1,3,4-oxadiazole derivatives were exclusively Keywords: hydrazides; 1,3,4-oxadiazoles/1,3,4-oxa-
formed from N’-tert-butylhydrazides and 1,3,4-oxa- diazolines; pyridine activation; switching; 1,2,4-tria-
diazoline derivatives were produced from N-phenyl- zoles
Introduction
ploited in the development of organic light emitting
diodes (OLEDS) owing to their unique optoelectronic
[
8]
The control of reaction site selectivity in a chemical properties. Furthermore, triazole salt derivatives ex-
reaction is an essential goal and a challenging issue hibit large positive heats of formation, due to the
for synthetic organic chemists. The ability to control presence of the large number of NÀN and CÀN bonds
the selectivity of a reaction is an important aspect in and often show remarkable insensitivity towards elec-
the construction of diversified products starting from trostatic discharge, friction, and impact. Hence, these
the same starting material. This can be approached by compounds are used as precursors in the preparation
either altering various reaction conditions or even by of energy-related materials, including applications
[9]
varying the substituents on the starting material. A such as explosives, propellants, and pyrotechnics.
review of the literature revealed that regioselectivity Considering the range of potential applications of
is mostly controlled by substituent groups reagents
and catalysts/ligands. However, achieving this might thetic protocols for accessing functionalized com-
also be accomplished by exploring the concept of re- pounds represents an attractive goal to the synthetic
gioselective switching by varying the reaction condi- community. A literature survey revealed that the Cu-
,
[1]
[2]
these heterocycles the development of efficient syn-
[
3]
tions more than one at a time.
catalyzed imine CÀH functionalization of N-arylide-
[10]
Five-membered heterocyclic compounds are core nearyl hydrazides,
components of many substances that have a wide acylhydrazones with various oxidizing agents,
range of applications in the pharmaceutical industry dehydrative cyclization of 1,2-diacylhydrazines with
and also in material science. Among this class, 1,3,4- various dehydrating agents are all known strategies
oxadiazole/1,3,4-oxadiazoline and 1,2,4-triazole deriv- for preparing 2,5-diaryl-1,3,4-oxadiazole derivatives
atives have been extensively used as motifs in the from hydrazide derivatives reported by various re-
preparation of interesting substances in various thera- search groups. The most important raw materials used
the oxidative cyclization of N-
[11]
the
[
12]
[
4]
[5]
peutic areas such as antibacterial, anticancer, anti- in the synthesis of these oxadiazole derivatives are hy-
[6]
[7]
inflammatory and anticonvulsant preparations. In drazide-hydrazones and hydrazones. In addition, the
addition to the medicinal properties of the 1,3,4-oxa- method often involves tedious synthetic procedures
diazoles, their 2,5-diaryl derivatives have been ex- and low yields for the synthesis of 1,3,4-oxadiazoles.-
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There are few reports on the prepartion of 1,3,4-oxa- Table 1. Optimization studies.
[
13]
diazolines from hydrazides.
Although there are
a number of reports on the synthesis of di- or tri-sub-
stituted 1,2,4-triazoles, there are very few reports in
the literature on the synthesis of salts of 2,3,4,5-poly-
[
14]
substituted 1,2,4-triazole derivatives. Hence, the de-
velopment of a simple and practical procedure start-
ing from a common starting material would be highly
desirable. To the best of our knowledge, there are no
reports in the literature on the preparation of 1,3,4-
oxadiazoles/1,3,4-oxadiazolines or 1,2,4-triazoles de-
rivatives starting from an N’-aryl/alkylhydrazide pre-
[
[
a]
b]
All the reactions were carried out with 0.5 mmol (SM),
-fluoropyridine (1.1 equiv.), and triflic anhydride
1.2 equiv.).
Yields refer to isolated and purified compounds.
2
(
[15]
cursor alone.
Results and Discussion
arylation of pyridine with 1-chloro-2,4-dinitrobenzene,
[
17]
We envisioned that N’-substituted hydrazides could i.e., Zincke activation and in the second case pro-
be converted to diaziridine derivatives in the presence motion through N-cyanation takes place with cyano-
[
18]
of an acid anhydride and a base. To validate our hy- gen bromide, i.e., Kçnig activation. However, a lit-
pothesis, we used N’-phenylbenzohydrazide 1a as erature survey revealed that there are no reports on
a model substrate and examined its reaction with acid pyridine scaffold activation using triflic anhydride for
anhydrides such as Ac O, TFAA and Tf O in the the generation of diene analogues.
2
2
presence of 2-fluoropyridine. In the presence TFAA
Once the conditions were optimized, we investigat-
and Ac O, the N’-acetylated product was isolated ed the scope and limitations of this interesting trans-
2
whereas in the case of Tf O, the 1,3,4-oxadiazoline de- formation. To our delight this methodology was found
2
rivative was produced instead of the diaziridine deriv- to be compatible with a variety of substrates including
ative in 30% yield (the structure was further con- aryl and alkyl groups, as shown in Table 2. A moder-
[
16]
firmed by X-ray crystallography)
Scheme 1.
as shown in ate yield of 68% of the desired product was observed
with an unsubstituted arylhydrazide precursor i.e., N’-
In order to further improve the product yield, sol- phenylbenzohydrazide (Table 2, entry 1). Hydrazides
vents such as DCM, DCE, CHCl , MeCN were em- derived from electron-donating substituents on the
3
ployed as shown in Table 1. In the case of CHCl , the aryl side such as methyl, methoxy groups (Table 2, en-
3
yield of the desired oxadiazoline derivative was in- tries 2, 3 and 4) worked well and those with mild elec-
creased to 68% from 30%. Next, attempts to increase tron-withdrawing groups, such as chloro, bromo
the product yield by increasing the amount of the re- groups also afforded the desired products in moderate
agent led to failure.
yields (Table 2, entries 5 and 6).
A careful literature survey revealed that there are
Even N’-phenylalkylhydrazides are more efficient
only two methods for the transformation of pyridine in the formation of desired oxadiazolines derivatives
compounds to conjugated dienes through the ring when compared to their aryl counter parts (Table 2,
cleavage of an N-alkylpyridinium salt. In the first entries 7, 8 and 9). This may be due to the fact that
case, a nucleophilic attack promoted through the N- the nitrogen on an aliphatic compound is more nucle-
ophilic, compared to its aromatic partner. On the
other hand, the present transformation was also
found to be compatible with various N’-aryl-substitut-
ed benzohydrazides including those with electron-do-
nating (Table 2, entries 10 and 11) as well as electron-
withdrawing substituents such as fluoro, chloro and
bromo (Table 2, entries 12, 13 and 14) but the yields
were low in the cases of electron-withdrawing groups.
The desired oxadiazoline product was not observed in
the case of an N’-4-nitrophenyl substituent. In the
case where both aryl rings of the hydrazide were sub-
stituted (Table 2, entries 15 and 16) moderate yields
of the desired product were observed.
We were further interested to check the scope of
Scheme 1. Hypothesis.
the present transformation with N’-alkylhydrazides.
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[a,b]
[a,b]
Table 2. Scope for the 1,3,4-oxadiazolines.
Table 3. Scope for the 1,3,4-oxadiazoles
zoles.
and the 1,2,4-tria-
[a,b,c]
[a]
Hydrazide
(1 equiv.),
2-fluoropyridine/pyridine
(
1.1 equiv.), triflic anhydride (1.2 equiv.), CHCl , À308C
3
to room temperature, 12 h.
Isolated yields.
[
[
b]
c]
1
0–15% starting material recovered.
of the desired product, 2,5-diphenyl-1,3,4-oxadiazole,
is lower (Table 3, entry 6).
To evaluate the scope of the reaction with base ad-
ditives, the 2-fluoropyridine was replaced with pyri-
dine and the reaction examined using N’-phenylben-
[
a]
Hydrazide (1 equiv.), 2-fluoropyridine (1.1 equiv.), triflic
anhydride (1.2 equiv.), CHCl , À308C to room tempera-
3
ture, 1 h.
1
zohydrazide as the substrate. From H NMR and crys-
[
[
b]
c]
Isolated yields.
tallographic data we observed the formation of a new
product, a 2,3,4,5-tetrasubstituted-1,2,4-triazole triflic
3-Phenyl-2,3-dihydro[1,2,4]triazolo[4,3-a]pyridin-1-ium
trifluoromethanesulfonate (13) was formed as product.
[
16]
acid salt. The scope was studied by reacting various
substrates on both sides of the hydrazide precursor in-
cluding aliphatic and aromatic moieties. In all the
To accomplish this, we examined the reaction with N’- cases, the reaction afforded the desired triazole salts
tert-butylphenylhydrazide under the same reaction in low yields, as shown in Table 3. In all cases 10–15%
conditions. To our surprise, the symmetrical 2,5-di-
phenyl-1,3,4-oxadiazole was produced in 75% yield
(
Table 3, entry 1) instead of an oxadiazoline deriva-
tive. We further investigated the present transforma-
tion by keeping the N’-tert-butyl substituent constant
and changing various substituents on the aryl ring
and, in all cases, symmetrical 2,5-diaryl-1,3,4-oxadia-
zole derivatives were obtained in reasonable yields, as
shown in Table 3. It is clear from the data in the
Table that the current transformation proceeds well
with electron-donating substituents (Table 3, entries 2
and 4) compared to electron-withdrawing substituents
(
Table 3, entries 3 and 5). However, in the case of an Scheme 2. Reactions of in presence of 2-chloropyridine and
N’-tosyl substituent on the benzohydrazide the yield 2-methylpyridine.
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of unreacted starting material was recovered. When plished by simply changing the substituent or the re-
the amount of reagent was increased, the starting ma- agent, the mechanism of the current transformation is
terial began to decompose. Furthermore, it was possi- clearly of interest. A proposed reaction mechanism is
ble to replace pyridine with other substituted pyri- shown in Figure 1.
dines such as 2-chloropyridine and 2-methylpyridine
2-Fluoropyridine and triflic anhydride react to form
in this reaction. With both chloropyridine and methyl- an N-trifyl cationic pyridinium intermediate which un-
pyridine the reactions provided the corresponding tri- dergoes S Ar substitution with N’-phenylbenzohydra-
N
[
19]
azole salts in 30% and 35% yields, respectively zide to form intermediate 10. Intramolecular attack
(
Scheme 2).
by the carbonyl oxygen followed by ring opening of
the pyridine nucleus affords the desired 1,3,4-oxadia-
zoline derivative 3a. On the other hand due to the
high electrophilicity of triflic anhydride, the triflic
Plausible Mechanism
[
20]
enolate is formed
with phenylhydrazide 1 in the
Since the formation of three different products start- presence of pyridine which is the common intermedi-
ing from a single starting material can be accom- ate for both Paths I and II. Due to the more nucleo-
philic nature of nitrogen in the case of N’-phenylphe-
nylhydrazide, the formation of intermediate 6 takes
place. In Path I the nucleophilic attack of an amide
oxygen may lead to the formation of the intermediate
7
since the nucleophilicity of nitrogen is quenched in
the presence of N’-tert-butylphenylhydrazide due to
the steric hindrance of the tertiary butyl group. Both
intermediates could undergo cyclization to afford the
desired oxadiazole 4a and triazole 5a products from
their respective intermediates.
To gain some insights into Path III for the reaction
mechanism, some experiments were carried out with
different halopyridines. Except for fluoropyridine no
other halopyridine participated in this transformation.
A further confirmation for this argument comes from
the fact that the order of reactivity for halogens to-
wards nucleophilic substitution is F>Cl>Br>I. This
order clearly suggests that stronger dipole bonds asso-
ciated with more electronegative atoms favour the ad-
dition step, thus lowering the energy of activation of
the nucleophilic addition step. In order to confirm the
SNAr mechanism, we prepared more sterically hin-
dered and more electron-withdrawing hydrazide sub-
strates, i.e., N’-2,4-dichlorophenylmethylhydrazides/
N’-2,4-dichlorophenylethylhydrazides
1
and per-
formed the reaction under conditions that were simi-
lar to those used for the synthesis of 1,3,4-oxadiazo-
line derivatives. After the prescribed time, the unex-
pected pyrazole pyridine fused products 11 and 12
(
structures were further confirmed by X-ray crystal-
lography) were isolated which, confirms the S Ar
N
mechanism (Scheme 3).
Figure 1. A plausible mechanism.
Scheme 3. Control experiment.
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Conclusions
General Procedure for the Synthesis of 1,3,4-
Oxadiazole Derivatives (4)
In conclusion, we report herein on a novel protocol in
which substituted 1,3,4-oxadiazole/1,3,4-oxadiazoline
and 1,2,4-triazole derivatives are prepared from hy-
drazide precursors alone using triflic anhydride and 2-
2
-Fluoropyridine (53.4 mg, 0.55 mmol, 1.1 equiv.) was added
to solution of N’-tert-butylphenylhydrazide (96 mg,
.5 mmol, 1 equiv.) in 5 mL CHCl3 at À308C. Triflic anhy-
dride (169 mg, 0.6 mmol, 1.2 equiv.) was then added drop-
a
0
fluoropyridine/pyridine. In this protocol, we observed wise to the reaction mixture. After the addition, the reaction
a regioselectivity substituent/reagent switch in the mixture was stirred at room temperature for 12 h. After the
synthesis of oxadiazoline (fluoropyridine acts as the prescribed time, the reaction mixture was quenched with
aqueous sodium bicarbonate solution (aq. NaHCO3 solu-
tion) and the organic phase was extracted with ethyl acetate,
washed with brine, and then purified by flash column chro-
matography with 30% ethyl acetate/hexane on silica gel to
afford the desired product.
reactant), oxadiazole and triazole salt derivatives
(
pyridine acts as a base additive) starting from
a single starting material. Also a new mode of activa-
tion of the 2-fluoropyridine scaffold was introduced
using triflic anhydride for the formation of penta-2,4-
diene derivatives i.e., a Zincke reaction by ring cleav-
age of the pyridine nucleus. Polyene motifs derived
from pyridinium salts can also be utilized further as
General Procedure for the Synthesis of 1,2,4-Triazole
Derivatives (5)
[
21]
useful synthons in total synthesis. Our current ef- Triflic anhydride (338 mg, 1 mmol, 1.2 equiv.) was added to
forts are directed to extending the scope of this inter- a solution of pyridine (158 mg, 2 mmol, 2 equiv.) in 5 mL of
CHCl at À308C to form a milky white solution. N-phenyl-
esting regioselective switch for the synthesis of other
sulfur and oxygen heterocycles as well as natural
products by varying the reaction conditions.
3
benzohydrazide (212 mg, 1 mmol, 1 equiv.) solution (in
CHCl3) was then added dropwise to the reaction mixture.
After the addition, the reaction mixture was stirred at room
temperature for 12 h. After the prescribed time the solvent
was removed by vacuum evaporation and then purified by
flash column chromatography without work-up with metha-
nol/DCM on silica gel.
Experimental Section
General Information
Spectral Data
All chemicals were purchased from various sources and
were used directly without further purification. All reactions
were carried out in dried glassware. Analytical thin-layer
chromatography was performed using silica gel 60F glass
plates and silica gel 60 (230–400 mesh) was used in flash
chromatographic separations. NMR spectra were recorded
in CDCl with CHCl and DMSO-d with DMSO as the in-
{
1
N-4-[3,5-Diphenyl-1,3,4-oxadiazol-2(3H)-ylidene]but-2-en-
-ylidene}-1,1,1-trifluoromethanesulfonamide (3a): Yield:
1
1
43 mg (68%); orange solid; mp 162–1648C; H NMR
(400 MHz, CDCl ): d=8.36 (d, J=11.0 Hz, 1H), 8.04 (d, J=
3
7
1
5
1
1
.4 Hz, 2H), 7.96 (t, J=13.2 Hz, 1H), 7.67 (t, J=7.42 Hz,
H), 7.64–7.53 (m, 7H), 6.18 (dd, J=13.3, 11.1 Hz, 1H),
.72 (d, J=13.2 Hz, 1H); C NMR (100 MHz, CDCl ): d=
74.4, 159.1, 159.0, 158.2, 134.5, 133.6, 130.4, 130.2, 129.7,
3
3
1
6
13
ternal standards for H NMR (400 MHz) and for C NMR
13
3
(
100 MHz). All the acylhydrazides were preparation using
Li and co-workerꢁs procedure. Coupling constants are ex-
pressed in Hertz. HR-MS were recorded using MALDI, ESI
27.0, 123.8, 121.3, 120.1 (q, J =321.0 Hz), 114.8, 82.6; LR-
C,F
+
MS (ESI ): m/z (relative intensity)=444.01 (M+Na, 100),
+
or EI modes. Melting points were recorded using an elec-
+
+
4
22.1 (M+H) ; HR-MS (TOF-ES ): m/z=422.0786, calcd.
trothermal capillary melting point apparatus and are uncor-
rected.
+
for C H F N O S (M+H) : 422.0786.
1
9
15
3
3
3
1
,1,1-Trifluoro-{N-4-[3-phenyl-5-p-tolyl-1,3,4-oxadiazol-
2
(3H)-ylidene]but-2-enylidene}methanesulfonamide (3b):
Yield: 130 mg (60%); orange solid; mp 200–2028C;
General Procedure for the Synthesis of 1,3,4-
Oxadiazoline Derivatives (3)
1
H NMR (400 MHz, CDCl ): d=8.35 (d, J=11.0 Hz, 1H),
3
7
.98–7.91 (m, 3H), 7.64–7.54 (m, 5H), 7.40 (d, J=8.0 Hz,
2
-Fluoropyridine (53.4 mg, 0.55 mmol, 1.1 equiv.) was added
to a solution of N-phenylbenzohydrazide (106 mg, 0.5 mmol,
equiv.) in 5 mL CHCl3 at À308C. Triflic anhydride
169 mg, 0.6 mmol, 1.2 equiv.) was then added dropwise to
2H), 6.17 (dd, J=13.3, 11.1 Hz, 1H), 5.71 (d, J=13.2 Hz,
1
3
1H), 2.48 (s, 3H); C NMR (100 MHz, CDCl ): d=174.0,
3
1
(
159.3, 159.1, 158.3, 144.8, 134.5, 130.5, 130.4, 130.2, 127.0,
123.8, 120.1 (q, J =321.0 Hz), 118.3, 144.5, 82.5, 22.0; LR-
C,F
+
the reaction mixture. After the addition of the triflic anhy-
dride, the colour of the reaction mixture became orange.
After the latter procedure, the reaction mixture was stirred
at room temperature for one hour. After the prescribed
time the reaction mixture was quenched with an aqueous
MS (ESI ): m/z (relative intensity)=458.05 (M+Na, 100);
+
HR-MS
(TOF-ES ):
m/z=436.0942,
calcd.
for
+
C H F N O S (M+H) : 436.0943.
2
0
17
3
3
3
1,1,1-Trifluoro-[N-4-[5-(4-methoxyphenyl)-3-phenyl-1,3,4-
oxadiazol-2(3H)-ylidene]but-2-en-1-ylidene}methanesulfona-
sodium bicarbonate solution (aq. NaHCO solution) and the
mide (3c): Yield: 153 mg (68%); orange solid; mp 163–
3
1
organic phase was extracted with ethyl acetate, washed with
brine, and then purified by flash column chromatography
with 30% ethyl acetate/hexane on silica gel to afford the de-
sired product.
1658C; H NMR (400 MHz, CDCl ): d=8.35 (d, J=11.1 Hz,
3
1H), 7.98–7.90 (m, 3H), 7.64–7.54 (m, 5H), 7.08 (d, J=
8.8 Hz, 2H), 6.16 (dd, J=13.1, 11.2 Hz, 1H), 5.71 (d, J=
1
3
13.2 Hz, 1H), 3.93 (s, 3H); C NMR (100 MHz, CDCl ):
3
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+
d=174.0, 164.0, 159.2, 159.0, 158.1, 134.5, 130.4, 130.2, 129.2,
(M+Na, 100); HR-MS (TOF-ES ): m/z=374.0786, calcd.
+
1
8
29.0, 123.8, 120.1 (q, JC,F =321.0 Hz), 115.2, 114.4, 113.3,
for C H F N O S (M+H) : 374.0786.
{N-4-[5-(tert-Butyl)-3-phenyl-1,3,4-oxadiazol-2(3H)-ylid-
15
15
3
3
3
+
2.8, 55.9; LR-MS (ESI ): m/z (relative intensity)=474.16
+
(
M+Na, 100); HR-MS (TOF-ES ): m/z=452.0894, calcd.
ACHTUNGTRENNUNG
+
for C H F N O S (M+H) : 452.0892.
(3i): Yield 140 mg (70%); orange solid; mp 216–2188C;
H NMR (400 MHz,CDCl ): d=8.29 (d, J=11.0 Hz, 1H),
20
17
3
3
4
1
1,1,1-Trifluoro-{N-4-[5-(2-methoxyphenyl)-3-phenyl-1,3,4-
3
oxadiazol-2(3H)-ylidene]but-2-en-1-ylidene}methanesulfona-
7.81 (t, J=13.3 Hz, 1H), 7.58 (t, J=7.6 Hz, 2H), 7.53–7.49
mide (3d): Yield: 124 mg (55%); orange solid, mp 156–
(m, 3H), 6.12 (dd, J=13.2, 11.2 Hz, 1H), 5.64 (d, J=
1
13
1
1
2
1
1
1
5
588C; H NMR (400 MHz, CDCl ): d=8.34 (d, J=11.0 Hz,
H), 7.94–7.88 (m, 2H), 7.65–7.53 (m, 6H), 7.18–7.12 (m,
13.3 Hz, 1H), 1.49 (s, 9H); C NMR (100 MHz, CDCl ):
3
3
d=173.9, 168.4, 159.7, 158.4, 134.4, 130.3, 130.1, 123.8, 120.2
+
H), 6.16 (dd, J=13.3, 11.1 Hz, 1H), 5.70 (d, J=13.2 Hz,
(q, JC,F =321 Hz), 114.1, 82.6, 33.0, 27.7; LR-MS (ESI ): m/z
1
3
H), 4.02 (s, 3H); C NMR (100 MHz, CDCl ): d=174.0,
(relative intensity)=424.20 (M+Na, 100); HR-MS (TOF-
3
+
+
58.8, 158.7, 158.3, 158.0, 135.2, 134.6, 130.4, 130.2, 124.2,
24.0, 121.3, 120.2 (q, JC,F =321 Hz), 114.4, 112.4, 110.1, 82.6,
ES ): m/z=402.1099, calcd. for C H F N O S (M+H) :
17 19 3 3 3
402.1099.
6.4.; LR-MS (ESI+): m/z (relative intensity)=474.53 (M+
1,1,1-Trifluoro-{N-4-[5-phenyl-3-(p-tolyl)-1,3,4-oxadiazol-
2(3H)-ylidene]but-2-en-1-ylidene}methanesulfonamide (3j):
+
Na, 100); HR-MS (TOF-ES ): m/z=452.0894, calcd. for
C H F N O S (M+H) : 452.0892.
+
1
Yield: 142 (65%); orange solid; mp 110–1128C; H NMR
20
17
3
3
4
{N-4-[5-(4-Chlorophenyl)-3-phenyl-1,3,4-oxadiazol-2(3H)-
(400 MHz, CDCl ): d=8.35 (d, J=11.0 Hz, 1H), 8.03 (d, J=
3
ylidene]but-2-en-1-ylidene}-1,1,1-trifluoromethanesulfona-
7.4 Hz, 2H), 7.94 (t, J=13.2 Hz, 1H), 7.67 (t, J=7.4 Hz,
1H), 7.61–7.58 (m, 2H), 7.46 (d, J=8.4 Hz, 2H), 7.41 (d, J=
8.3 Hz, 2H), 6.16 (dd, J=13.2, 11.2 Hz, 1H), 5.67 (d, J=
mide (3e): Yield: 141 mg (62%); orange solid; mp 210–
1
2
1
1
128C; H NMR (400 MHz, CDCl ): d=8.40 (d, J=10.9 Hz,
3
1
3
H), 7.99–7.90 (m, 3H), 7.64–7.55 (m, 7H), 6.19 (t, J=
2.2 Hz, 1H), 5.70 (d, J=13.1 Hz, 1H); C NMR (100 MHz,
13.2 Hz, 1H), 2.47 (s, 3H); C NMR (100 MHz, CDCl ):
3
1
3
d=174.2, 159.2, 158.9, 158.1, 140.9, 133.6, 131.9, 131.0, 129.7,
CDCl ): d=168.8, 161.0, 160.1, 158.9, 138.8, 134.1, 131.0,
127.0, 123.8, 121.3, 120.1(q, J =321 Hz), 114.2, 82.6, 21.5;
3
C,F
+
1
1
30.6, 130.3, 129.9, 129.2, 120.6, 120.5 (q, JC,F =323 Hz),
LR-MS (ESI ): m/z (relative intensity)=458.14 (M+Na,
+
+
13.4, 87.9; LR-MS (ESI ): m/z (relative intensity)=478.19
100); HR-MS (TOF-ES ): m/z=436.0942, calcd. for
+
+
(
M+Na, 100); HR-MS (TOF-ES ): m/z=456.0397, calcd.
C H F N O S (M+H) : 436.0943.
2
0
17
3
3
3
+
for C H ClF N O S (M+H) : 456.0396.
{N-4-[3-(2,5-Dimethylphenyl)-5-phenyl-1,3,4-oxadiazol-
2(3H)-ylidene]but-2-en-1-ylidene}-1,1,1-trifluoromethanesul-
19
14
3
3
3
{N-4-[5-(4-Bromophenyl)-3-phenyl-1,3,4-oxadiazol-2(3H)-
ylidene]but-2-en-1-ylidene}-1,1,1-trifluoro methanesulfona-
fonamide (3k): Yield: 135 mg (60%); orange solid; mp 194–
1
mide (3f): Yield 144 mg (58%); orange solid; mp 201–
1968C; H NMR (400 MHz, CDCl ): d=8.32 (d, J=9.9 Hz,
3
1
2
038C; H NMR (400 MHz, CDCl ): d=8.41 (d, J=10.9 Hz,
1H), 8.08–7.92 (m, 3H), 7.68–7.58 (m, 3H), 7.34 (s, 2H),
3
1
H), 7.96–7.89 (m, 3H), 7.75 (d, J=8.5 Hz, 2H), 7.64–7.53
7.20 (s, 1H), 6.09 (t, J=12.3 Hz, 1H), 5.22 (d, J=12.4 Hz,
1H), 2.42 (s, 3H), 2.24 (s, 3H); C NMR (100 MHz,
1
3
(
m, 5H), 6.19 (dd, J=13.3, 11.0 Hz, 1H), 5.70 (d, J=
13
1
1
1
8
5
3.1 Hz, 1H); C NMR (100 MHz, CDCl3): d=175.1, 158.9,
58.1, 158.0, 134.5, 133.2, 132.1, 131.8, 130.5, 130.2, 128.7,
28.3, 123.7, 120.2, 120.1 (q, J =320.9 Hz), 119.3, 115.2,
2.8; LR-MS (ESI ): m/z (relative intensity)=524.14 (100),
CDCl ): d=173.9, 160.5, 159.0, 158.0, 138.3, 133.6 132.8,
3
132.7, 132.5, 132.2, 129.7, 127.5, 127.0, 121.3, 120.1 (q, J
321.0 Hz), 114.2, 82.3, 20.9, 17.3; LR-MS (ESI ): m/z (rela-
tive intensity)=472.13 (M+Na, 100); HR-MS (TOF-ES ):
=
C,F
+
C,F
+
+
+
+
22.16 (M+Na, 93); HR-MS (TOF-ES ): m/z=499.9890,
m/z=450.1099, calcd. for C H F N O S (M+H) :
2
1
19
3
3
3
+
calcd. for C H F N O SBr (M+H) : 499.9891.
450.1099.
19
14
3
3
3
{N-4-[5-Benzyl-3-phenyl-1,3,4-oxadiazol-2(3H)-ylidene]-
{N-4-[3-(4-Chlorophenyl)-5-phenyl-1,3,4-oxadiazol-2(3H)-
but-2-en-1-ylidene}-1,1,1-trifluoro methanesulfonamide (3g):
Yield 141 mg (65%); orange solid; mp 124–1268C; H NMR
ylidene]but-2-en-1-ylidene}-1,1,1-trifluoromethanesulfona-
1
mide (3l): Yield: 114 mg (50%); orange solid; mp 212–
1
(
400 MHz, CDCl ): d=8.25 (d, J=11.0 Hz, 1H), 7.73 (t, J=
2148C; H NMR (400 MHz, CDCl ): d=8.41 (d, J=11.0 Hz,
3
3
1
7
3.3 Hz, 1H), 7.57 (t, J=7.6 Hz, 2H), 7.52–7.49 (m, 3H),
.46–7.38 (m, 5H), 6.09 (dd, J=13.2, 11.2 Hz, 1H), 5.61 (d,
1H), 8.03 (d, J=7.6 Hz, 2H), 7.95 (t, J=13.3 Hz, 1H), 7.68
(t, J=7.4 Hz, 1H), 7.62–7.54 (m, 6H), 6.20 (t, J=12.2 Hz,
1
3
13
J=13.2 Hz, 1H), 4.17 (s, 2H); C NMR (100 MHz, CDCl ):
1H), 5.68 (d, J=13.0 Hz, 1H); C NMR (100 MHz, CDCl ):
3
3
d=174.1, 160.7, 159.6, 158.3, 134.3, 131.6, 130.3, 130.1, 129.6,
d=175.3, 158.8, 158.6, 158.0, 135.9, 133.7, 133.1, 130.7, 129.8,
1
3
29.2, 128.6, 123.7, 120.1 (q, J =320.0 Hz), 114.5, 82.5,
127.0, 125.2, 121.2, 120.0 (q, J =320.0 Hz), 115.2, 81.8; LR-
C,F
C,F
+
+
1.9; LR-MS (ESI ): m/z (relative intensity)=458.51 (M+
MS (TOF-ES ): m/z (relative intensity)=456.04 (M+H,
+
+
Na, 100); HR-MS (TOF-ES ): m/z=436.0941, calcd. for
C H F N O S (M+H) : 436.0943.
100); HR-MS (TOF-ES ): m/z=456.0397, calcd. for
+
+
C H F N O SCl (M+H) : 456.0396.
20
17
3
3
3
19 14
3
3
3
{
N-4-[5-Ethyl-3-phenyl-1,3,4-oxadiazol-2(3H)-ylidene]but-
1,1,1-Trifluoro-{N-4-[3-(4-fluorophenyl)-5-phenyl-1,3,4-ox-
adiazol-2(3H)-ylidene]but-2-en-1-ylidene}methanesulfona-
2
-en-1-ylidene}-1,1,1-trifluoromethanesulfonamide (3h):
Yield: 140 mg (75%); orange solid; mp 191–1938C;
mide (3m): Yield: 121 mg (55%); orange solid; mp 204–
1
1
H NMR (400 MHz, CDCl ): d=8.23 (d, J=11.1 Hz, 1H),
2068C; H NMR (400 MHz, CDCl ): d=8.38 (d, J=10.9 Hz,
3
3
7
3
1
.80 (t, J=13.3 Hz, 1H), 7.60–7.56 (m, 2H), 7.53–7.49 (m,
H), 6.10 (dd, J=13.2, 11.2 Hz, 1H), 5.64 (d, J=13.3 Hz,
H), 2.90 (q, J=7.5 Hz, 2H), 1.45 (t, J=7.5 Hz, 3H);
1H), 8.03 (d, J=7.6 Hz, 2H), 7.94 (t, J=13.2 Hz, 1H), 7.67
(t, J=7.4 Hz, 1H), 7.62–7.58 (m, 4H), 7.34–7.29 (m, 2H),
6.18 (dd, J=13.2, 11.2 Hz, 1H), 5.63 (d, J=13.1 Hz, 1H);
13
13
C NMR (100 MHz, CDCl ): d=173.6, 163.2, 159.7, 158.4,
C NMR (100 MHz, CDCl ): d=175.0, 164.3, 161.7 (d,
3
3
1
134.4, 130.3, 130.1, 123.8, 120.1 (q, J =321 Hz), 114.2, 82.9,
JCF =250 Hz), 159.1, 158.9, 158.0, 133.7, 130.6, 129.8, 127.0,
C,F
+
2
19.3, 9.9; LR-MS (ESI ): m/z (relative intensity)=396.18
126.2, 126.1 (d, JC,F =8.7 Hz), 121.2, 120.1(q, JC,F
=
Adv. Synth. Catal. 0000, 000, 0 – 0
6
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ÞÞ
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FULL PAPERS
asc.wiley-vch.de
+
+
3
21.0 Hz), 117.8, 117.5, 115.1, 81.8; LR-MS (ESI ): m/z (rel-
123.2; LR-MS (EI ): m/z (relative intensity)=290.0 (73),
+
+
ative intensity)=461.94 (M+Na, 100); HR-MS (TOF-ES ):
m/z=440.0694, calcd. for C H F N O S (M+H) :
199.0 (100); HR-MS (TOF-ES ): m/z=291.0092, calcd. for
C H N OCl (M+H) : 291.0092.
+
+
1
9
14
4
3
3
14
9
2
2
4
40.0692.
2,5-Bis(4-methoxyphenyl)-1,3,4-oxadiazole (4d):1 Yield:
{N-4-[3-(4-Bromophenyl)-5-phenyl-1,3,4-oxadiazol-2(3H)-
101 mg (72%); white solid; mp 167–1698C; H NMR
ylidene]but-2-en-1-ylidene}-1,1,1-trifluoromethanesulfona-
(400 MHz, CDCl ): d=8.05–8.03 (m, 2H), 7.03–6.99 (m,
3
1
3
mide (3n): Yield: 100 mg (40%); orange solid; mp 215–
2H), 3.87 (s, 3H); C NMR (100 MHz, CDCl ): d=164.3,
3
1
+
2
1
7
2
178C; H NMR (400 MHz, CDCl ): d=8.41 (d, J=10.8 Hz,
162.4, 128.7, 116.7, 114.6, 55.6; LR-MS (EI ): m/z (relative
3
+
+
H), 8.03 (d, J=7.5 Hz, 2H), 7.94 (t, J=13.3 Hz, 1H), 7.76–
.73 (m, 2H), 7.68 (t, J=7.4 Hz, 1H), 7.60 (t, J=7.5 Hz,
H), 7.53–7.47 (m, 2H) 6.20 (dd, J=13.3, 11.1 Hz, 1H), 5.68
intensity)=282.1 (M , 100); HR-MS (TOF-ES ): m/z=
+
283.1084, calcd. for C H N O (M+H) : 283.1083.
1
6
15
2
3
2,5-Bis(4-chlorophenyl)-1,3,4-oxadiazole
93 mg (64%); white solid; mp 250–2528C; H NMR
(4e):
Yield:
3
1
(
d, J=13.0 Hz, 1H); C NMR (100 MHz, CDCl ): d=175.3,
3
1
1
58.9, 158.6, 158.0, 133.7, 133.7, 133.6, 129.7, 127.0, 125.0,
(400 MHz, CDCl ): d=8.06 (d, J=7.2 Hz, 2H), 7.52 (d, J=
3
1
3
23.8, 121.2, 120.1 (q, J =320.0 Hz), 115.4, 81.9; LR-MS
7.1 Hz, 2H); C NMR (100 MHz, CDCl ): d=164.1, 138.4,
C,F
3
+
+
(TOF-ES ): m/z (relative intensity)=499.99 (M+H, 100);
129.7, 128.4, 122.4; LR-MS (EI ): m/z (relative intensity)=
+
+
HR-MS
(TOF-ES ):
m/z=499.9887,
calcd.
for
290.0 (50), 199.0 (82), 139.0 (100); HR-MS (TOF-ES ): m/
+
+
C H F N O SBr (M+H) : 499.9891.
z=291.0095, calcd. for C H N OCl (M+H) : 291.0092.
19
14
3
3
3
14
9
2
2
1
,1,1-Trifluoro-{N-4-[5-(4-methoxyphenyl)-3-(p-tolyl)-
,3,4-oxadiazol-2(3H)-ylidene]but-2-en-1-ylidene}methane-
sulfonamide (3o): Yield: 116 mg (50%); orange solid; mp
1,3,5-Triphenyl-4-(phenylamino)-4H-1,2,4-triazol-4-ium
1
trifluoromethanesulfonate (5a): Yield: 270 mg (50%); white
1
solid; mp 183–1858C; H NMR (400 MHz, CDCl ): d=9.41
3
1
2
1
7
1
2
1
03–2058C; H NMR (400 MHz, CDCl ): d=8.32 (d, J=
(s, 1H), 8.07 (dd, J=8.4, 1.1 Hz, 2H), 7.65 (dd, J=8.4,
1.2 Hz, 2H), 7.57–7.53 (m, 5H), 7.51–7.46 (m, 4H), 7.43–
7.39 (m, 2H), 7.11 (dd, J=8.4, 7.6 Hz, 2H), 6.85 (t, J=
3
1.1 Hz, 1H), 7.98–7.88 (m, 3H), 7.45 (d, J=8.5 Hz, 2H),
.40 (d, J=8.5 Hz, 2H), 7.09–7.06 (m, 2H), 6.14 (dd, J=
3.2, 11.2 Hz, 1H), 5.66 (d, J=13.3 Hz, 1H), 3.93 (s, 3H),
.47 (s, 3H); C NMR (100 MHz, CDCl ): d=173.6, 164.0,
59.1, 159.1, 158.0, 140.9, 131.9, 131.0, 129.0, 123.8, 120.1 (q,
JC,F =321 Hz), 115.3, 114.1, 113.3, 82.9, 55.9, 21.5; LR-MS
TOF-ES ): m/z (relative intensity)=466.11 (M+H, 100);
HR-MS
1
3
7.5 Hz, 1H), 6.57–6.54 (m, 2H); C NMR (100 MHz,
13
CDCl ): d=155.9, 154.4, 143.4, 135.5, 133.8, 133.0, 131.5,
3
3
130.7, 130.2, 129.8, 129.6, 129.5, 129.3, 129.2, 127.2, 125.5,
+
122.7, 120.2 (q, JC,F =325.0 Hz), 113.5; HR-MS (TOF-ES ):
+
+
(
m/z=389.1767, calcd. for C H N (M ): 389.1766; HR-MS
2
6
21
4
+
À
+
(TOF-ES ):
m/z=466.1051,
calcd.
for
(TOF-ES ): m/z=148.9521, calcd. for CF SO3 (M ):
3
+
C H F N O S (M+H) : 466.1048.
148.9520
21
19
3
3
4
1,1,1-Trifluoro-{N-4-[3-(4-fluorophenyl)-5-(p-tolyl)-1,3,4-
1-Phenyl-4-(phenylamino)-3,5-di-p-tolyl-4H-1,2,4-triazol-
oxadiazol-2(3H)-ylidene]but-2-en-1-ylidene}methanesulfona-
4-ium trifluoromethanesulfonate (5b): Yield: 306 mg (54%);
1
mide (3p): Yield: 120 mg (53%); orange solid; mp 208–
white solid; mp 206–2088C; H NMR (400 MHz, CDCl ):
3
1
2
1
8
1
108C; H NMR (400 MHz, CDCl ): d=8.36 (d, J=11.0 Hz,
d=9.41 (s, 1H), 7.95 (d, J=8.1 Hz, 2H), 7.55–7.45 (m, 7H),
7.24 (t, J=7.7 Hz, 2H), 7.16 (d, J=8.1 Hz, 2H), 7.10 (t, J=
7.8 Hz, 2H), 6.82 (t, J=7.4 Hz, 1H), 6.56 (d, J=8.0 Hz,
3
H), 7.97–7.90 (m, 3H), 7.61–7.58 (m, 2H), 7.39 (d, J=
.1 Hz, 2H), 7.33–7.29 (m, 2H), 6.17 (dd, J=13.2, 11.2 Hz,
H), 5.63 (d, J=13.1 Hz, 1H), 2.48 (s, 3H); C NMR
1
3
13
2H), 2.35 (s, 3H), 2.30 (s, 3H); C NMR (100 MHz,
1
(
100 MHz, CDCl3): d=174.6, 164.2 (d, JC,F =251 Hz), 161.7,
CDCl ): d=155.8, 154.5, 144.9, 143.6, 143.5, 135.7, 131.3,
3
1
1
1
59.2, 159.1, 158.1, 144.8, 130.6, 130.5, 130.5, 127.0, 126.2,
130.5, 130.3, 130.1, 130.0, 129.8, 129.2, 125.5, 122.4, 120.6 (q,
2
26.1 (d, JC,F =8.8 Hz), 120.1 (q, JC,F =321.0 Hz), 118.3,
JC,F =317.0 Hz), 119.0, 115.4, 113.2, 21.9, 21.8; LR-MS (EI):
+
+
17.7, 117.5, 114.8, 82.1, 22.0; LR-MS (ESI ): m/z (relative
m/z (relative intensity)=250.1 (M , 100), 220.1 (52), 191.0
+
+
intensity)=476.16 (M+Na, 100); HR-MS (TOF-ES ): m/
z=454.0848, calcd. for C H F N O S (M+H) : 454.0848.
(39); HR-MS+ (TOF-ES ): m/z=417.2079, calcd. for
+
À
C H N (M ): 417.2079; HR-MS (TOF-ES ): m/z=
2
0
16
4
3
3
28 25
4
+
2
,5-Diphenyl-1,3,4-oxadiazole (4a): Yield: 83 mg (75%);
148.9522, calcd. for CF SO (M ): 148.9520.
3 3
1
white solid; mp 144–1468C; H NMR (400 MHz, CDCl ):
d=8.15–8.13 (m, 2H), 7.55–7.15 (m, 3H);
3,5-Dibenzyl-1-phenyl-4-(phenylamino)-4H-1,2,4-triazol-4-
3
1
3
C NMR
ium trifluoromethanesulfonate (5c): Yield: 295 mg (52%);
1
(100 MHz, CDCl ): d=164.8, 131.9, 129.2, 127.1, 124.1; LR-
thick liquid; H NMR (400 MHz, CDCl ): d=9.40 (s, 1H),
3
3
+
MS (EI ): m/z (relative intensity)=222.1 (78), 165.1 (100);
HR-MS (TOF-ES ): m/z=223.0872, calcd. for C H N O
7.52 (d, J=7.1 Hz, 3H), 7.46 (d, J=7.0 Hz, 2H), 7.17–7.12
(m, 7H), 7.08–7.01 (m, 3H), 6.95 (t, J=7.4 Hz, 1H), 6.74 (d,
J=7.4 Hz, 2H), 6.56 (d, J=8.1 Hz, 2H), 4.48 (s, 2H), 4.16
+
14
11
2
+
(
M+H) : 223.0871.
1
3
2
,5-Di-p-tolyl-1,3,4-oxadiazole (4b): Yield: 87 mg (70%);
(s, 2H); C NMR (100 MHz, CDCl ): d=157.1, 156.4, 142.7,
3
1
white solid; mp 178–1808C; H NMR (400 MHz, CDCl ):
134.6, 131.7, 131.5, 130.0, 129.7, 129.4, 129.0, 129.0, 128.9,
3
d=8.00 (d, J=8.1 Hz, 2H), 7.31 (d, J=8.0 Hz, 2H), 2.42 (s,
128.7, 128.1, 127.6, 125.9, 123.1, 120.6 (q, J =317.0 Hz),
C,F
13
+
3
1
2
H). C NMR (100 MHz, CDCl ): d=164.6, 142.3, 129.9,
113.6, 30.4 30.0; HR-MS (TOF-ES ): m/z=417.2079, calcd.
3
+
+
À
27.0, 121.4, 21.8; LR-MS (EI ): m/z (relative intensity)=
for C H N (M ): 417.2079; HR-MS (TOF-ES ): m/z=
28 25 4
+
+
50.1 (98), 179.1 (100); HR-MS (TOF-ES ): m/z=251.1185,
148.9521, calcd. for CF SO (M ): 148.9520.
3 3
+
calcd. for C H N O (M+H) : 251.1184.
3,5-Bis(4-chlorophenyl)-1-phenyl-4-(phenylamino)-4H-
16
15
2
2
,5-Bis(2-chlorophenyl)-1,3,4-oxadiazole
0 mg (62%); white solid; mp 98–1008C; H NMR
400 MHz, CDCl ): d=8.10 (dd, J=7.6, 1.7 Hz, 1H), 7.56
(4c): 1 Yield:
1,2,4-triazol-4-ium trifluoromethanesulfonate (5d): Yield:
304 mg (50%); white solid; mp 186–1888C; H NMR
1
9
(
(
(
(400 MHz, CDCl ): d=9.27 (s, 1H), 8.00–7.97 (m, 2H),
3
3
1
3
dd, J=7.9, 1.1 Hz, 1H), 7.50–7.40 (m, 2H); C NMR
100 MHz, CDCl ): d=163.6, 133.4, 132.7, 131.5, 127.3,
7.59–7.48 (m, 7H), 7.42–7.38 (m, 2H), 7.35–7.33 (m, 2H),
7.15 (t, J=7.9 Hz, 2H), 6.88 (t, J=7.4 Hz, 1H), 6.57 (d, J=
3
Adv. Synth. Catal. 0000, 000, 0 – 0
7
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

FULL PAPERS
asc.wiley-vch.de
1
3
7
1
1
1
.9 Hz, 2H); C NMR (100 MHz, CDCl ): d=155.0, 153.8,
CDCl ): d=132.5, 130.8, 130.5, 129.5, 128.8, 128.4, 127.6,
3
3
51.7, 143.0, 140.8, 139.7, 135.3, 132.1, 131.7, 130.7, 130.3,
30.1, 129.7, 125.6, 123.1, 120.5 (q, J =317.0 Hz), 120.2,
16.7, 113.4; HR-MS (TOF-ES ): m/z=457.0986, calcd. for
C H N Cl (M ): 457.0987; HR-MS (TOF-ES ): m/z=
127.5, 126.5,122.8, 120.1 (q, J =323.0 Hz), 116.9, 114.8;
C,F
+
HR-MS (TOF-ES ): m/z=196.0876, calcd. for C H N
C,F
12 10
3
+
+
À
(M ): 196.0875; HR-MS (TOF-ES ): m/z=148.9521, calcd
+
+
À
for CF SO (M ): 148.9520.
3 3
26
19
4
2
+
1
48.9521, calcd. for CF SO (M ): 148.9520.
3 3
1-(4-Fluorophenyl)-4-[(4-fluorophenyl)amino]-3,5-diphen-
yl-4H-1,2,4-triazol-4-ium trifluoromethanesulfonate (5e):
1
Yield: 201 mg (35%); thick liquid; H NMR (400 MHz,
Acknowledgements
CDCl ): d =9.51 (s, 1H), 8.01 (d, J=7.6 Hz, 2H), 7.64 (d,
3
H
J=7.6 Hz, 2H), 7.58–7.55 (m, 2H), 7.51 (t, J=7.4 Hz, 2H),
Financial support by the Ministry of Science and Technology
of the Republic of China (MOST 103-2113M-003-008-MY3),
National Taiwan Normal University (103-07-C) and Instru-
mentation Centre at National Taiwan Normal University is
gratefully acknowledged. The authors are grateful to Ms.
Hsiu-Ni Huan, Ms. Chiu-Hui He and Ting-Shen Kuo for
providing HR-MS, NMR and crystallographic data, respec-
tively.
7
8
.43–7.35 (m, 4H), 7.12 (t, J=8.4 Hz, 2H), 6.76 (t, J=
.5 Hz, 2H), 6.58–6.55 (m, 2H); C NMR (100 MHz,
1
3
CDCl ): d=165.1, 162.6 (d, J =252.0 Hz), 159.7, 157.3 (d,
3
C,F
JC,F =240.0 Hz), 155.6, 154.4, 139.6, 139.5, (d, JC,F =2.3 Hz),
1
1
33.9, 133.0, 131.6, 131.5 (d, JC,F =3.3 Hz), 130.6, 129.6,
29.4, 129.3, 127.9, 127.8 (d, JC,F =9.2 Hz), 121.8, 120.6 (q,
JC,F =317.0 Hz), 117.5, 117.2 (d, JC,F =23.0 Hz), 116.6, 116.4
d, JC,F =23 Hz), 116.0, 115.4, 115.3 (d, J =8.0 Hz); HR-
(
C,F
+
+
MS (TOF-ES ): m/z=425.1579, calcd. for C H N F (M ):
4
CF SO (M ): 148.9520.
2
6
19
4 2
À
25.1578; HR-MS (TOF-ES ): m/z=148.9521, calcd. for
+
3
3
References
1
-(3-Chlorophenyl)-4-[(3-chlorophenyl)amino]-3,5-di-
phenyl-4H-1,2,4-triazol-4-ium trifluoromethanesulfonate
5f): Yield: 243 mg (40%); white solid; mp 215–2178C;
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H NMR (400 MHz, CDCl ): d=9.62 (s, 1H), 8.04–8.02 (m,
3
2
H), 7.69–7.66 (m, 3H), 7.61–7.56 (m, 2H), 7.55–7.45 (m,
5
8
H), 7.42–7.39 (m, 2H), 7.04 (t, J=8.4 Hz, 1H), 6.81 (d, J=
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1
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3
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3
1
1
1
33.7, 133.0, 131.5, 131.3, 131.1, 130.3, 129.5, 129.3, 128.5,
25.7, 124.4, 121.6, 121.6, 120.6 (q, J =320 Hz), 118.3,
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+
12.5, 111.6; HR-MS (TOF-ES ): m/z=457.0989, calcd. for
+
À
C H N Cl (M ): 457.0987; HR-MS (TOF-ES ): m/z=
1
26
19
4
2
+
48.9521, calcd. for CF SO (M ): 148.9520.
3 3
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din-4-ium trifluoromethanesulfonate (11): Yield: 302 mg
6
857; b) E. P. Jackson, J. Montgomery, J. Am. Chem.
1
(
70%); white solid; mp 118–1208C; H NMR (400 MHz,
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3
(
3
1
d, J=8.5 Hz, 1H), 7.72–7.68 (m, 2H), 7.56–7.53 (m, 2H),
13
.02 (s, 3H); C NMR (100 MHz, CDCl ): d=146.6, 143.9,
3
39.5, 139.1, 132.0, 131.8, 130.8, 130.4, 129.6, 127.6, 120.5 (q,
1
5422; f) V. Kavala, C.-C. Wang, Y. H. Wang, C. W.
+
JC,F =317.0 Hz), 119.5, 110.5, 10.6; HRMS (TOF-ES ): m/
z=278.0252, calcd. for C H N Cl (M ): 278.0252; HR-MS
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+
1
3
10
3
2
À
+
(TOF-ES ): m/z=148.9521, calcd. for CF SO (M ):
3 3
1
48.9520.
-(2,4-Dichlorophenyl)-3-ethyl-[1,2,4]triazolo[4,3-a]pyri-
din-4-ium trifluoromethanesulfonate (12): Yield: 266 mg
1
1
(
60%); white solid; mp 122–1248C; H NMR (400 MHz,
CDCl ): d=8.84 (d, J=6.8 Hz, 1H), 8.16 (dd, J=8.8, 7.4 Hz,
3
1
H), 7.88 (d, J=8.6 Hz, 1H), 7.72–7.67 (m, 2H), 7.56–7.53
1
3
(
(
m, 2H), 3.36 (q, J=7.4 Hz, 2H), 1.49 (s, 3H); C NMR
100 MHz, CDCl ): d=150.4, 143.9, 139.7, 139.0, 132.1,
3
1
1
31.7, 130.8, 130.5, 129.5, 127.4, 120.6 (q, JC,F =318.0 Hz),
+
19.6, 110.6, 18.4, 9.3; HR-MS (TOF-ES ): m/z=292.0408,
+
+
calcd. for C H N Cl (M ): 292.0408; HR-MS (TOF-ES ):
m/z=148.9523, calcd. for CF SO (M ): 148.9520.
14
12
3
2
+
3
3
3
-Phenyl-[1,2,4]triazolo[4,3-a]pyridin-1-ium trifluorome-
1
thanesulfonate (13): Yield: 50 mg (14%); gum; H NMR
(
(
7
400 MHz, CDCl ): d=8.26 (d, J=7.0 Hz, 1H), 7.84–7.74
3
m, 4H), 7.58–7.53 (m, 3H), 7.34 (t, J=7.5, Hz, 1H), 7.30–
1
3
.26 (m, 1H), 6.87 (t, J=6.7 Hz, 1H); C NMR (100 MHz,
Adv. Synth. Catal. 0000, 000, 0 – 0
8
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10 Reagent/Substituent Switching Approach for the Synthesis
of Substituted 1,3,4-Oxadiazole/1,3,4-Oxadiazoline and
1,2,4-Triazole Derivatives from N-Substituted Hydrazides
Adv. Synth. Catal. 2016, 358, 1 – 10
Trimurtulu Kotipalli, Veerababurao Kavala, Ashok Konala,
Donala Janreddy, Chu-Wei Kuo, Ching-Fa Yao*
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