A simple and effective method for the thionation of amides to thioamides using Al2O3-supported P4S10 was developed and applied to a series of amides including some heterocyclic examples. The reaction was best performed in anhydrous dioxane at reflux temperature. Yields ranging from 62 - 93% are comparable to, or superior to those obtained with Lawessons reagent. The method uses inexpensive reagents and has the advantage that reagent-derived byproducts may be removed by a simple hydrolytic workup rather than by chromatography, as required for Lawessons reagent.
Keywords: thioamide, thionation, heterocycles, lawessons reagent, supported reagents
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