Abstract
A facile and highly efficient method for one-pot Beckmann rearrangement of ketoximes into N-substituted amides using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, ketoximes are refluxed with TsIm and Cs2CO3 in the presence of SiO2 as a recyclable catalyst in DMF affording the corresponding amides in high yields. This methodology is highly efficient and regioselective for various structurally diverse ketoximes including symmetrical and unsymmetrical as well as cyclic oximes. The results of quantum mechanical studies used to rationalize the experimental outcomes are discussed.
Acknowledgments
We wish to thank the Shiraz University of Technology and Shiraz University Research Councils for partial support of this work.
Notes
a Isolated yield.
b Anhydrous DMF.
c No reaction.
d (1:1) ratio.
a Isolated yield.
b Basic alumina.
a Isolated yield.
b No reaction.
a Isolated yield.
a All products were characterized by 1H and 13C-NMR, IR, CHN and MS analysis.
b Isolated yield.
a The ratios were attained by HPLC analysis.
a Charges in Mulliken unit.