S.D. Salim et al. / Catalysis Communications 13 (2011) 78–81
81
Table 4
Reusability study .
4. Conclusion
a
In conclusion the present work describes a simple and highly
efficient protocol, for a three component Willgerodt–Kindler reaction
for synthesis of thiomorpholides using aryl alkyl ketones, sulfur and
morpholine under solvent-free conditions giving very good to
excellent yields. The remarkable catalytic activity exhibited by
sulfated tungstate is convincingly superior to other acid catalysts
with respect to high yield, reaction temperature and catalyst amount.
Operational simplicity, simple procedure for preparation catalyst,
catalyst stability and reusability are noteworthy features.
Run no.
% yield of 1-morpholino-2-phenylethanethione
Fresh
95
94
94
92
90
First recycle
Second recycle
Third recycle
Fourth recycle
a
Loss of catalyst (b5%) during handling.
to corresponding thiomorpholide in very good yield (entry 12, Table 3).
Reaction failed to occur with aliphatic ketone as substrates.
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1
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1
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