The Willgerodt Reaction allows the synthesis of amides from aryl ketones under the influence of a secondary amine and a thiating agent. The mechanism involves the formation of an enamine which undergoes thiation, and the carbonyl group migrates to the end of the chain via a cascade of thio-substituted iminium-aziridinium rearrangements.
The Kindler Modification is more convenient:
Hydrolysis of the thioamide provides the amide.
Mechanism of the Willgerodt-Kindler Reaction