Ultrasound-Promoted Three-Component Reaction of N -isocyaniminotriphenyl-phosphorane, (E)-cinnamic Acids, and Biacetyl

Article abstract of DOI:10.1080/10426507.2014.909428

Fully substituted 1,3,4-oxadiazole derivatives were obtained in a one-pot three-component reaction of N-isocyaniminotriphenylphosphorane, biacetyl, and (E)-cinnamic acids in dichloromethane under ultrasound irradiation. This rapid method produced the products in short reaction times (16-27 min) and excellent yields (91-97%). GRAPHICAL ABSTRACT.

Full text of DOI:10.1080/10426507.2014.909428

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Phosphorus, Sulfur, and Silicon and the
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Ultrasound-Promoted Three-Component
Reaction of N-Isocyaniminotriphenyl-
Phosphorane, (E)-Cinnamic Acids, and
Biacetyl
Ali Ramazania, Morteza Rouhanib, Fatemeh Zeinali Nasrabadic &
Farideh Gouranloud
a Department of Chemistry, Zanjan Branch, Islamic Azad University,
Zanjan, Iran
b Department of Chemistry, University of Zanjan, Zanjan, Iran
c Department of Chemistry, Payame Noor University, Tehran, Iran
d Science and Biotechnology Research Center, Malek Ashtar
University of Technology, Tehran, Iran
Accepted author version posted online: 18 Jun 2014.Published
online: 02 Dec 2014.
To cite this article: Ali Ramazani, Morteza Rouhani, Fatemeh Zeinali Nasrabadi & Farideh Gouranlou
(2014): Ultrasound-Promoted Three-Component Reaction of N-Isocyaniminotriphenyl-Phosphorane,
(E)-Cinnamic Acids, and Biacetyl, Phosphorus, Sulfur, and Silicon and the Related Elements, DOI:
10.1080/10426507.2014.909428
To link to this article: http://dx.doi.org/10.1080/10426507.2014.909428
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Phosphorus, Sulfur, and Silicon, 189:1–9, 2014
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2014.909428
ULTRASOUND-PROMOTED THREE-COMPONENT
REACTION OF N-ISOCYANIMINOTRIPHENYL-
PHOSPHORANE, (E)-CINNAMIC ACIDS, AND BIACETYL
Ali Ramazani,1 Morteza Rouhani,2 Fatemeh Zeinali Nasrabadi,3
and Farideh Gouranlou4
1Department of Chemistry, Zanjan Branch, Islamic Azad University, Zanjan, Iran
2Department of Chemistry, University of Zanjan, Zanjan, Iran
3Department of Chemistry, Payame Noor University, Tehran, Iran
4Science and Biotechnology Research Center, Malek Ashtar University of
Technology, Tehran, Iran
GRAPHICAL ABSTRACT
C
N
N
O
O
OH
O
N
CH2Cl2
))), r.t.
N
H3C
CH3
(Ph)3P=O
+
Ar
+
OH
+
H3C
CH3
O
R
O
(Ph)3P
Ar
R
Abstract Fully substituted 1,3,4-oxadiazole derivatives were obtained in a one-pot three-
component reaction of N-isocyaniminotriphenylphosphorane, biacetyl, and (E)-cinnamic acids
in dichloromethane under ultrasound irradiation. This rapid method produced the products in
short reaction times (16–27 min) and excellent yields (91–97%).
Keywords 1,3,4-oxadiazole; N-isocyaniminotriphenylphosphorane; biacetyl; (E)-cinnamic
acid; ultrasound irradiation; aza-Wittig reaction
INTRODUCTION
Throughout the past decade, isocyanide-based multicomponent reactions (IMCR)
earned considerable concern within the scientific community as an efficient, convenient,
time-saving, and atom-economical approach to rapidly generate chemical diversity. IM-
CRs are easily performed using readily available starting materials and bear a diver-
sity range of functional groups. Variations and following transformations give approach
to a clearly large number of unique structures that would otherwise demand lengthy
preparations.1,2
In recent times, the intramolecular version of the aza-Wittig–type reaction has at-
tracted much attention because it has showed high potential for the synthesis of a broad
Received 30 January 2014; accepted 25 March 2014.
Address correspondence to Ali Ramazani, Department of Chemistry, Zanjan Branch, Islamic Azad
University, P O Box 49195-467, Zanjan, Iran. E-mail: aliramazani@gmail.com
1

2
A. RAMAZANI ET AL.
diversity of nitrogen heterocycles, which can be ascribed, in good measure, to the rapid
development in the preparation of functionalized iminophosphoranes. Existence of the
nucleophilicity at the nitrogen is a factor of necessary mechanistic significance in the
use of these iminophosphoranes as aza-Wittig reagents. Iminophosphoranes are important
reagents in synthetic organic chemistry, especially in the synthesis of naturally occurring
products, compounds with biological and pharmacological activity3,4. In recent years, we
have explored a synthetic ability of N-isocyaniminotriphenylphosphorane in the synthesis of
various organic compounds5–13. It looks that the N-isocyaniminotriphenylphosphorane has
excellent synthetic potential because it provides a reaction system in which the iminophos-
phorane group can react with a reagent having a carbonyl functionality.
In recent years there has been important investigation on different classes of oxa-
diazoles. Especially, compounds including 1,3,4-oxadiazole nucleus have been shown
to own a wide range of pharmacological and therapeutic activities. Different 1,3,4-
oxadiazoles have been reported to have a wide spectrum of biological activity, involv-
ing antimicrobial14–16, antifungal17,18, anti-inflammatory19, and hypotensive activity20. Few
credible and functionally simple examples have been reported for the one-pot synthe-
sis of 1,3,4- oxadiazoles, especially from readily available carboxylic acids and acid
hydrazides.21–25
Ultrasonic-assisted organic synthesis as a green synthetic path is a powerful tech-
nique that is being used more and more to accelerate organic reactions26,27. While the last
three decades, ultrasound-accelerated organic chemical reactions have been increasingly
improved by researchers beyond the globe for the synthesis of organic molecules. Ultra-
sound irradiation offers an optional energy source for organic reactions. Ultrasound-assisted
reactions continue by the formation, growth, and collapse of acoustic bubbles in the reac-
tion medium. These clearly help in shortening the time span of reactions and increasing
the yield of products. Many homogeneous and heterogeneous organic reactions have been
directed efficiently by sonication. A large number of organic reactions can be carried out in
higher yields, shorter reaction time, or milder conditions under ultrasound irradiation and
considered a processing aid in terms of energy conservation and waste minimization which
compared with traditional methods28–31. As in continuation of our work on the synthesis
of heterocycles32–35 and in order to enlarge the application of ultrasound irradiation in the
synthesis of heterocyclic compounds, we report herein a simple and efficient method for
the preparation of fully substituted 1,3,4-oxadiazole derivatives under ultrasonic irradiation
(Scheme 1).
C
N
N
O
O
OH
O
N
CH2Cl2
))), r.t.
N
H3C
CH3
+
Ar
OH
+
H3C
(Ph)3P=O
CH3
O
R
O
(Ph)3P
Ar
R
1
2
3
4
5
Scheme 1

SYNTHESIS OF FULLY SUBSTITUTED 1,3,4-OXADIAZOLES
3
Table 1 Effect of different solvents for synthesis of 4a under ultrasound irradiation at room temperature
Entrya
Solvent
Time (min)
Yield (%)b
1
2
3
4
5
6
DMF
THF
CH3CN
1,4-dioxane
EtOH
30
25
20
30
30
16
34
52
72
48
54
97
CH2Cl2
aReaction conditions: 1 mmol 4-methylcinnamic acid, 1 mmol N-isocyaniminotriphenylphosphorane, and
1 mmol biacetyl in 15 mL solvent.
bIsolated yield.
RESULTS AND DISCUSSION
In our initial research, 4-methylcinnamic acid was selected as a representative re-
actant in order to optimize the reaction conditions. We conducted the one-pot three-
component condensation reaction of N-isocyaniminotriphenylphosphorane, biacetyl, and
4-methylcinnamic acid in the presence of various solvents. We examined the effect of dif-
ferent solvents such as CH2Cl2, DMF, THF, CH3CN, 1,4-dioxane, and EtOH on a model
reaction under ultrasound irradiation at room temperature. The results are listed in Table 1.
The reaction using CH2Cl2 as solvent gave the best result (Table 1, entry 6). The reaction
failed to give poor yields in DMF, THF, CH3CN, 1,4-dioxane, and EtOH (Table 1, entries
1–5).
To demonstrate the effect of ultrasound, the synthesis of 4a as a model was investigated
under stirring and ultrasound conditions. The results are shown in Table 2. Under stirring
conditions, the reaction can be completed within 12 h to give 4a in 92% yield (Table 2,
entry 1). Whereas under ultrasonic irradiation in 100 W, 4a was obtained in 97% yield
within 16 min (Table 2, entry 3). We also observed the effect of power of the ultrasound
irradiation on the reaction. The yield with 100 W irradiation for 16 min (Entry 3) was better
than that with 150 W irradiation for 16 min (Entry 4). The reason may be that the lower
power irradiation produces the better cavitations36. As shown in Tables 1 and 2, we selected
the CH2Cl2 as solvent under ultrasound irradiation conditions with 100 W power for the
one-pot reaction of N-isocyaniminotriphenylphosphorane, biacetyl, and (E)-cinnamic acids
to give corresponding 1,3,4-oxadiazole derivatives at room temperature.
Thus, we have carried out a series of experiments and the results are summarized in
Table 3. In order to show the advantages of the present experimental conditions, in Table 3
Table 2 Comparison of the yields for the synthesis of 4a as a model
Entry
Condition
Time (min)
Yield (%)a
1
2
3
4
Stirring in CH2Cl2 at room temperature
12 h
16
16
92
62
97
79
Ultrasonic in CH2Cl2 at room temperature (50 W)
Ultrasonic in CH2Cl2 at room temperature (100 W)
Ultrasonic in CH2Cl2 at room temperature (150 W)
16
aIsolated yield.

4
A. RAMAZANI ET AL.
Table 3 The synthesis of fully substituted 1,3,4-oxadiazole derivatives (4a–g) under ultrasound irradiation and
stirring condition at room temperature
US
Conventional stirring
Producta
R, Ar
t (min)
Yield (%)b
t (h)
Yield (%)b
4a
4b
4c
4d
4e
4f
H, 4-MeC6H4
H, 4-F-C6H4
H, 4-Cl-C6H4
H, C6H5
Me, C6H5
H, 3-ClC6H4
H, 3-MeOC6H4
16
18
20
27
23
19
22
97
96
94
91
92
94
93
12
12
12
12
12
12
12
92
90
88
85
85
86
87
4g
aReaction conditions: 1 mmol (E)-cinnamic acid, 1 mmol N-isocyaniminotriphenylphosphorane, and 1 mmol
biacetyl in CH2Cl2.
bIsolated yield.
we have also collected the results under conventional conditions by stirring in CH2Cl2 as
well as under ultrasound irradiation. As shown in Table 3, the condensation of a variety
of substituted (E)-cinnamic acids, N-isocyaniminotriphenylphosphorane, and biacetyl in
CH2Cl2 proceeds smoothly to afford the respective products in excellent yields (91–97%)
within 16–27 min.
The method to obtain fully substituted 1,3,4-oxadiazole derivatives (4a–g) under
ultrasonic irradiation offers several significant advantages including faster reaction rates,
higher yields, higher purity, and the smoothly reaction proceeds at room temperature.
In comparison with routine methods, the main benefit of ultrasound application is the
significant decline in the reaction times. Thus, while conventional method using stirring
in CH2Cl2 requires 12 h, ultrasonic irradiation affords the respective products in only
16–27 min (see Table 3).
These results encourage that the energy provided by ultrasound accelerates these
reactions. The distinction in yields and reaction times may be a result of the particular
effects of ultrasound. The effect observed on the reaction is due to cavitation, a physical
process that creates, enlarges, and collapses gaseous and vaporous cavities in an irradiated
liquid, therefore improving the mass transfer and permitting chemical reactions to happen.
The creation of the so-called hot spots in the reaction mixture produces great local tem-
peratures and high pressures created inside the cavitation bubble and its interfaces when it
collapses37. Under these situations, very reactive chemical species are produced, with a very
short lifetime, giving rise to the 1,3,4-oxadiazole derivatives (4a–g) in shorter times, thus
facilitating the deprotonation step that is critical in this type of multi-component reactions.
Moreover, compared with traditional methods (see Table 3), this technique is more efficient
and less time consuming.
The reaction consists in several successive steps (Scheme 2). On the basis of the chem-
istry of isocyanides38, it is reasonable to assume that the first step may involve nucleophilic
addition of the N-isocyaniminotriphenylphosphorane 3 to biacetyl 1, which facilitates by its
protonation with the acid 2, leading to nitrilium intermediate 6. This intermediate may be
attacked by conjugate base of the acid 2 to form 1:1:1 adduct 7. This adduct may undergo
intramolecular aza-Wittig reaction39–41 of iminophosphorane moiety with the ester car-
bonyl to afford the isolated sterically congested 1,3,4-oxadiazole derivatives 4 by removal
of triphenylphosphine oxide 5 from intermediate 8.

SYNTHESIS OF FULLY SUBSTITUTED 1,3,4-OXADIAZOLES
5
R
Ar
O
O
Ar
HO
2
O
O
O
R
CH3
CH3
)))
H3C
)))
H3C
(Ph)3P
N
N
C
C
HO
P(Ph)3
N
3
O
N
1
6
O
R
OH
N
P(Ph)3
O
H3C
O
N
Ar
O
N
N
)))
R
H3C
H3C
HO
O
O
Ar
CH3
7
P(Ph)3
8
O
OH
N
N
H3C
(Ph)3P=O
CH3
O
Ar
R
Scheme 2
As it is known, the nucleophilic addition of the N-isocyaniminotriphenylphosphorane
to biacetyl has negative activation volume owing to the condensation of the molecules into a
reactive intermediate. In this regard, it is well-known that reactions with negative activation
volumes are accelerated with pressure42 On the other hand, ultrasound irradiation37,43 as well
as solvophobic interactions of ionic liquids generate a microscopic internal pressure in the
solvent cavity44. Our reaction, owning to the ultrasonic cavitations generates a microscopic
internal high pressure and high temperature. Accordingly, it is reasonable to assume that
these effects should accelerate this type of one-pot three-component reaction.
As shown in Table 3, the electronic effect and the nature of the substituent on the (E)-
cinnamic acids aromatic ring did not show any remarkable effect in terms of yields, under
the same reaction conditions. Obviously, the presence of different groups in (E)-cinnamic
acids 2 do not alter significantly the yields obtained. To the best of our knowledge, this
new procedure provides the first example of an efficient and ultrasound-promoted approach
for the synthesis of fully stituted 1,3,4-oxadiazole derivatives. This method is the most
simple and convenient and would be applicable for the synthesis of different types of
1,3,4-oxadiazoles.
CONCLUSION
In this work, we have developed a mild, highly efficient, and improved protocol for
the preparation of a series of fully substituted 1,3,4-oxadiazoles. Our sonochemical method

6
A. RAMAZANI ET AL.
offers several advantages over existing methods, including improved yields, cleaner reac-
tions, simple work-up, and short-reaction times, which makes it a useful and environmen-
tally attractive strategy for the synthesis of 1,3,4-oxadiazole derivatives, compounds with
promising bioactivity.
EXPERIMENTAL
General Considerations
All reagents were obtained from Merck (Germany) and Fluka (Switzerland) and used
without further purification. Infrared spectra were recorded on a Jasco 6300 FTIR spectrom-
eter. 1H and 13C NMR spectra of CDCl3 solutions were obtained with a BRUKER DRX-250
AVANCE spectrometer at 250.0 and 62.5 MHz, respectively using tetramethylsilane (TMS)
as the internal standard. Elemental analysis was performed with a Heraeus CHN-O-Rapid
analyzer. Mass spectra were recorded on a Finnigan MAT 8430 mass spectrometer operat-
ing at an ionization potential of 70 eV. Melting points were measured on an Electrothermal
9100 apparatus and are uncorrected. Sonication was performed in a Bandelin SONOPULS
ultrasonic homogenizers (made in Germany) with 20 kHz processing frequency, a nominal
power 250 W, uniform sonic waves. Preparative layer chromatography (PLC) plates were
prepared from Merck silica gel (F254) powder. N-Isocyaniminotriphenylphosphorane 3 was
prepared on the basis of reported procedures.4
Synthesis of 1,3,4-Oxadiazoles 4a–g by Conventional Method
A mixture of N-isocyaniminotriphenylphosphorane (1.0 mmol; 0.300 g), biacetyl
(1.0 mmol; 0.10 mL), and (E)-cinnamic acid (1.0 mmol) in CH2Cl2 (5 mL) was stirred
at room temperature for 12 h. The solvent was removed under reduced pressure, and
the viscous residue was purified by PLC [silica gel (F254) powder; petroleum ether/
ethyl acetate 4:1].
Synthesis of 1,3,4-Oxadiazoles 4a–g by Ultrasound Irradiation
In a 25 mL beaker, N-isocyaniminotriphenylphosphorane (1.0 mmol; 0.300 g), bi-
acetyl (1.0 mmol; 0.10 mL), and (E)-cinnamic acid (1.0 mmol) were mixed with CH2Cl2
(15 mL). The reaction mixtures were then sonicated by an ultrasonic probe with a power
of 100 W at room temperature. The complete consumption of reagents occurred after
16–27 min, as monitored by TLC. The solvent was removed, and the viscous residue was
purified by PLC [silica gel (F254) powder; petroleum ether/ethyl acetate 4:1].
SPECTRAL DATA OF PRODUCTS
3-Hydroxy-3-{5-[(E)-2-(4-Methylphenyl)-1-Ethenyl]-1,3,4-Oxadiazol-
2-yl}-2-Butanone (4a)
White powder (291 mg, yield 97%), m.p 125–127◦C, 1H NMR (CDCl3, 250 MHz):
3
δH (ppm) 1.92, 2.35, 2.38 (s, 9H, 3CH3), 4.70 (s, 1H, OH), 6.95 (d, JHH = 16.5 Hz,
CH), 7.21 (d, 2H, 3JHH = 7.5 Hz, CHarom,), 7.43 (d, 2H, 3JHH = 7.5 Hz, CHarom,), 7.53 (d,
3JHH = 16.5 Hz, CH). 13C NMR (CDCl3, 62.5 MHz): δC (ppm) 21.47, 23.24,
23.75 (3CH3), 75.72 (C OH), 108.20, 140.20, (2CH ), 127.58, 129.77 (4CH, arom),

SYNTHESIS OF FULLY SUBSTITUTED 1,3,4-OXADIAZOLES
7
131.71140.69 (2C, arom), 164.67, 165.56 (2C N), 204.65 (C O). IR (Neat) (υmax
,
cm−1): 3298, 2998, 2918, 1723, 1644, 1532, 1363, 1180, 833. Ms m/z (%) 272 (M+,
20), 229 (100), 187 (72), 160 (32), 143 (68), 115 (52), 91 (24), 43 (96). Anal. Calcd for
C15H16N2O3 (272.12): C, 66.16; H, 5.92; N, 10.29. Found: C, 66.24; H, 5.97; N, 10.24.
3-{5-[(E)-2-(4-Fluorophenyl)-1-Ethenyl]-1,3,4-Oxadiazol-2-yl}-
3-Hydroxy-2-Butanone (4b)
White powder (288 mg, yield 96%), m.p 84–86◦C, 1H NMR (CDCl3, 250 MHz): δH
(ppm) 1.87, 2.35 (s, 6H, 2CH3), 4.70 (s, 1H, OH), 6.92 (d, 3JHH = 16.5 Hz, CH), 7.01–7.55
(m, 5H, CHarom and CH). 13C NMR (CDCl3, 62.5 MHz): δC (ppm) 23.25, 23.74, (2CH3),
75.74 (C OH), 109.02, 138.89 (2CH ), 116.22 (d, 2JCF = 28.3 Hz, 2CHarom), 129.44 (d,
3JCF = 8.2 Hz, 2CHarom), 130.70 (C, arom), 162.50 (d, 1JCF = 440.3 Hz, Carom), 164.85,
165.22 (2C N), 204.60 (C O). IR (Neat) (υmax, cm−1): 3372, 2923, 1731, 1670, 1529,
1505, 1163, 818. Ms m/z (%) 276 (M+, 12), 234 (100), 191 (56), 164 (32), 147 (60), 121
(20), 101 (24), 43 (68). Anal. Calcd for C14H13FN2O3 (276.09): C, 60.87; H, 4.74; N,
10.14. Found: C, 60.81; H, 4.80; N, 10.08.
3-{5-[(E)-2-(4-Chlorophenyl)-1-Ethenyl]-1,3,4-Oxadiazol-2-yl}-
3-Hydroxy-2-Butanone (4c)
White powder (282 mg, yield 94%), m.p 148–150◦C, 1H NMR (CDCl3, 250 MHz):
δH (ppm) 1.92, 2.35, (s, 6H, 2CH3), 4.67 (s, 1H, OH), 6.97 (d, 3JHH = 16.8 Hz, CH), 7.25
-7.54 (m, 5H, CHarom and CH). 13C NMR (CDCl3, 62.5 MHz): δC (ppm) 23.26, 23.72,
(2CH3), 75.72 (C OH), 109.84, 138.76 (2CH ), 128.73, 129.34 (4CH, arom), 132.90,
136.15 (2C, arom), 164.85, 165.12 (2C N), 204.51 (C O). IR (Neat) (υmax, cm−1): 3363,
2921, 1726, 1648, 1523, 1406, 1152, 815. Anal. Calcd for C14H13ClN2O3 (292.06): C,
57.44; H, 4.48; N, 9.57. Found: C, 57.39; H, 4.53; N, 9.52.
3-Hydroxy-3-{5-[(E)-2-Phenyl-1-Ethenyl]-1,3,4-Oxadiazol-
2-yl}-2-Butanone (4d)
1
White powder (273 mg, yield 91%), m.p 79–81◦C, H NMR (CDCl3, 250 MHz):
3
δH (ppm) 1.93, 2.36 (s, 6H, 2CH3), 4.69 (s, 1H, OH), 7.01 (d, JHH = 16.5 Hz, CH),
7.40–7.60 (m, 6H, CHarom and CH). 13C NMR (CDCl3, 62.5 MHz): δC (ppm) 23.26,
23.73 (2CH3), 75.71 (C OH), 109.28, 140.22 (2CH ), 127.60, 129.05, 130.24 (5CH),
134.41 (C, arom), 164.95, 165.35 (2C N), 202.6 (C O). IR (Neat) (υmax, cm−1): 3311,
2923, 1726, 1649, 1528, 1449, 1150, 759, 693. Anal. Calcd for C14H14N2O3 (258.10): C,
65.11; H, 5.46; N, 10.85. Found: C, 65.05; H, 5.40; N, 10.91.
3-Hydroxy-3-{5-[(E)-1-Methyl-2-Phenyl-1-Ethenyl]-1,3,4-Oxadiazol-
2-yl}-2-Butanone (4e)
1
Yellow viscous oil (276 mg, yield 92%), H NMR (CDCl3, 250 MHz): δH (ppm)
1.93, 2.36, 2.39 (s, 9H, 3CH3), 4.66 (s, 1H, OH), 7.36–7.51 (m, 6H, CHarom and CH). 13
C
NMR (CDCl3, 62.5 MHz): δC (ppm) 14.56, 23.25, 23.75 (3CH3), 75.75 (C OH), 128.52,
129.59, 135.25, 135.38 (4CH, arom), 120.90 (C, arom), 167.83, 170.00 (2C N), 204.68
(C O). IR (Neat) (υmax, cm−1): 3298, 2994, 2926, 1720, 1601, 1526, 1447, 1093, 713,

8
A. RAMAZANI ET AL.
695. Anal. Calcd for C15H16N2O3 (272.12): C, 66.16; H, 5.92; N, 10.29. Found: C, 66.24;
H, 5.84; N, 10.37.
3-{5-[(E)-2-(3-Chlorophenyl)-1-Ethenyl]-1,3,4-Oxadiazol-
2-yl}-3-Hydroxy-2-Butanone (4f)
1
White powder (282 mg, yield 94%), m.p 62–64◦C, H NMR (CDCl3, 250 MHz):
3
δH (ppm) 1.93, 2.36 (s, 6H, 2CH3), 4.69 (s, 1H, OH), 7.01 (d, JHH = 16.5 Hz, CH),
7.36–7.52 (m, 5H, CHarom and CH). 13C NMR (CDCl3, 62.5 MHz): δC (ppm) 23.28,
23.73, (2CH3), 75.72 (C OH), 110.71135.10 (2CH ), 125.71, 127.41, 130.11, 130.29
(4CH, arom), 136.20, 138.58 (2C, arom), 162.83, 164.95 (2C N), 204.87 (C O). IR
(Neat) (υmax, cm−1): 3274, 2923, 1728, 1650, 1528, 1426, 1110, 840, 789, 691. Anal.
Calcd for C14H13ClN2O3 (292.06): C, 57.44; H, 4.48; N, 9.57. Found: C, 57.49; H, 4.53;
N, 9.52.
3-Hydroxy-3-{5-[(E)-2-(3-Methoxyphenyl)-1-Ethenyl]-1,3,4-Oxadiazol-
2-yl}-2-Butanone (4g)
1
White powder (279 mg, yield 93%), m.p 70–72, H NMR (CDCl3, 250 MHz): δH
(ppm) 1.93, 2.35 (s, 6H, 2CH3), 3.83 (s, 3H, OCH3), 4.73 (s, 1H, OH), 6.91–7.35 (m,
3
5H, CHarom and CH), 7.52 (d, JHH = 16.5 Hz, CH). 13C NMR (CDCl3, 62.5 MHz):
δC (ppm) 23.26, 23.76 (2CH3), 55.31 (s, 3H, OCH3), 75.75 (C OH), 109.57, 140.12
(2CH ), 112.54, 116.05, 120.25, 130.04 (4CH), 135.77, 159.98 (2C), 164.87, 165.31
(2C N), 204.61 (C O). IR (Neat) (υmax, cm−1): 3236, 3004, 2922, 1730, 1650, 1580,
1466, 1108, 876, 795, 687. Anal. Calcd for C15H16N2O4 (288.11): C, 62.49; H, 5.59; N,
9.72. Found: C, 62.44; H, 5.64; N, 9.67.
ACKNOWLEDGMENTS
The authors thank Zanjan Islamic Azad University for the support and guidance.
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