2092 Bull. Korean Chem. Soc. 2011, Vol. 32, No. 6
Notes
Table 2. Comparison results of cesium carbonate with general
method of Gewald reaction , L-proline , KF-alumina , and ethylene-
diammonium diacetate as catalysts in the reaction of cyclohexa-
none and ethylcyano acetate
(0.035 g, 1.1 mmol), Cs CO
2
3
(0.05 g, 0.15 mmol) in 20 mL
ethanol, were heated at reflux for the time showed in Table
. When the reaction was complete (Thin-Layer Chromato-
1
graphy), the catalyst was filtered off, solvent was removed
by evaporation under reduced pressure and the crude
product was purified by recrystallization in ethanol to 2-
aminothiophenes in high yields.
EntryCondition
Catalyst
Time/min Yield%
1
2
3
4
Ethanol, 70 °C
Ethanol, 70 °C
DMF, 60 °C
Diethylamine
KF-alumina
L-Proline
240
210
82
89
84
84
1440
240
Acknowledgments. The corresponding author gratefully
acknowledges the financial support from the Research Council
of the Islamic Azad University, Bandar Abbas Branch.
Ionic liquid, 50 °C Ethylenediammonium
diacetate
Cesium carbonate
5
Ethanol, 70 °C
160
91
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2 3
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Ketone (1.0 mmol), nitrile (1.0 mmol), elemental sulfur