4
38 Letters in Organic Chemistry, 2012, Vol. 9, No. 6
Azarifar et al.
d]pyrimidines 7 as well as 1,4-dihydropyrano[2,3-c]pyrazol-
ACKNOWLEDGEMENT
5
-yl cyanides 8.
We wish to thank the research council of the University
of Bu-Ali Sina in Hamedan, Iran, for financial support to
carry out this research.ꢀꢀ
In conclusion, we have explored the application of ultra-
sonic irradiation technique as a rapid and versatile protocol
in the synthesis of 4H-chromenes, pyrano[2,3-d]pyrimidines,
and 4H-pyran derivatives in ethanol under the catalytic effect
of triethylamine. Simple manipulation of the products, im-
CONFLICT OF INTEREST
3
proved yields, and shorter reaction times, application of Et N
Declared none.
as an inexpensive and readily available catalyst and also use
of ethanol as a relatively environmentally benign solvent are
the main advantages of our method.
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2
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-Amino-4-(4-fluorophenyl)-5-cyano-3-methyl-1-
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2