Vol. 28, No. 12 (2016)
CuFe2O4 Nanoparticles Mediated Synthesis of 1,4-Disubstituted 1,2,3-Triazoles 2581
127.52, 128.01, 133.51, 135.42, 140.26, 147.94, 149.24. ESI
4-methyl-, 4-methoxy-, 4-pentyl- and 3-fluoro-substituted phenyl
acetylenes were found to be more reactive when compared to
the heteroaromatic alkyne (Table-1, entries 5-9).
MS (m/z): 251.1 (M+H)+.
RESULTS AND DISCUSSION
Conclusion
Aliphatic azides can be synthesized from the correspon-
ding halides by nucleophilic displacement or, in cases of vinyl
azides and aryl by a CuFe2O4 nanoparticles catalyzed reaction
with sodium azide. When we use activated halides like pro-
pargylic, benzylic and allylic, then the substitution is facile.
Herein, we report a CuFe2O4 nanoparticles mediated one-
pot synthesis of 1,4-disubstituted 1,2,3-triazoles by using a
three component coupling of trimethylsilylazide (TMSN3),
secondary alcohol and terminal alkynes (Scheme-I).
The variety of 1,4-disubstituted 1,2,3-triazoles were prepared
using benzylic/allylic alcohols, trimethylsilyl azide and
terminal alkynes via a simple one-pot, two-step procedure
involving the azidation of alcohols, followed by 1,3-dipolar
cycloaddition with terminal alkynes using CuFe2O4 nanopar-
ticles as catalyst. 1,4-Disubstituted 1,2,3-triazoles are obtained
in good to excellent yields without the need for the reactivation
and isolation of the azide intermediates.
ACKNOWLEDGEMENTS
R2
One of the authors (Chunduru Srinivasa Rao) thanks
Department of Chemistry, Jawaharlal Nehru Technological
University, Hyderabad, India for providing necessary facilities.
N
N
OH
R2
CuFe2O4
N
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TMSN3/room temperature,
5 h, Toluene
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Scheme-I
In this paper, we began with the direct conversion of an
alcohol with trimethylsilylazide into a alkyl azide intermediate.
This intermediate upon treated with phenylacetylene without
isolation to get the 1,4-disubstituted-1,2,3-triazole in an one-
pot operation via 1,3-dipolar cycloaddition product by using
CuFe2O4 nanoparticles as a catalyst. In this reaction, water plays
an important role such as (a) quenching of excess trimethylsilyl-
azide; (b) acetylene without any amine base and (c) formation
of copper acetylide from CuFe2O4 nanoparticles. As exempli-
fied in Table-1, the reaction proceeds smoothly to completion
and the yields are very good. The reaction of various secondary
benzylic alcohols bearing electron-rich and electron-poor
substituents underwent the reaction smoothly and gave the
products in good yield (Table-1, entries 1-4).
In order to disclose the importance of reaction, different
types of terminal alkynes derivatives were reacted with the
azides of benzylic alcohols, which were generated in situ. In
this reaction, it was observed that the reaction with a range of
different alkynes, such as substituted phenyl acetylenes,
aliphatic and hetero aromatic terminal alkynes, were fruitful
and the formed triazoles were obtained in good yields (85-
65 %). Among the various terminal alkynes used in this study,
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