S. Paik, J. Y. Lee / Tetrahedron Letters 47 (2006) 1813–1815
1815
TsOH and MsOH were employed under several
Acknowledgements
conditions. The use of 1 equiv of TsOH with 2 in
refluxing toluene showed no reaction, while 4 equiv of
TsOH (refluxing toluene) resulted in only 23% of the
cleavage product with mostly unchanged starting
material, indicating that MsOH was much more effi-
cient than TsOH for cleavage of the N-(1-phenylethyl)
moiety on an amide. The reaction of HCl-saturated
MeOH (reflux, 6 h) with 2 was also noted unchanged.
In cases where 1–4 equiv of MsOH or TsOH with 1
in refluxing toluene or TFA (refluxing dichlorometh-
ane) with 1 in the presence of anisole as a nucleophilic
scavenger were used, no significant changes were also
observed.
This present research has been conducted by the Bisa
Research Grant of Keimyung University in 2005.
References and notes
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In conclusion, a simple and efficient method using 0.5–
1 equiv MsOH in refluxing toluene was found to be
effectively applicable for cleavage of the N-(1-phenyl-
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for removal of
carboxamide.
a
methoxybenzyl group on
a
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