Odourless Thio-Beckmann Rearrangement

15 Examples, yields 24-90%

This paper describes an odourless one-pot process for conversion of oximes to thioamides.  The oxime is initially reacted with tosyl chloride and triethylamine at 0ºC in acetonitrile.  Thiourea is added and the reaction is refluxed for 2 hours.  Yields for 10 of the 15 examples are 69-90%.  R1 can be aryl or alkyl, with R2 being mainly methyl or ethyl although there are individual examples where R2 is phenyl, benzyl or cyclopropyl.  The reaction is worked up by quenching with brine followed by extraction with dichloromethane.

L.-F. Liu,* N. AN, H.-J. Pi, J. Ying, and W.-P. Dong, Synlett, 2011, (7), 979-981.