The Willgerodt Reaction

From N‐Substituted Thioamides to Symmetrical and Unsymmetrical 3,4,5‐Trisubstituted 4H‐1,2,4‐Triazoles: Synthesis and Characterisation of New Chelating Ligands

“…[32,33] However, it has been shown that this reaction can also be applied to 2-methylpyridine. [34,35] Thus, N-substituted pyridine-2-thiocarboxamides have been prepared by reaction of 2-methylpyridine with primary amines, [34,35] nitro compounds, [34] or N-substituted formamides [16,36] as amine sources in the presence of sulfur at elevated temperatures Scheme 2.…”

Synthesis of 1,n-Acyloxy Thioamides by the Willgerodt-Kindler Reaction: Chemoselectivity of 1,3-Ketoesters over 1,3-Diketones

“…A mechanistic study led to the chemoselective thioamidation of 1,3-ketoesters in the presence of 1,3-diketones. This is a new finding for the WK reaction which can be helpful for elucidating its reaction pathway that still remains obscure [13,18].…”

“…The purification is carried out by column chromatography on silica gel eluting with ethyl acetate/petroleum ether (1 : 3 v/v) to afford pure product 1. The identification of the isolated products was performed by 1 H NMR, 13 C NMR and GC-MS spectral analyses.…”

“…The three-component Willgerodt-Kindler (WK) reaction is well known as an alternative route for the synthesis of thioamides [13,14]. In the original reaction, an aryl alkyl ketone or aryl aldehyde was reacted with sulfur and a primary or secondary amine, to give the terminal thioamide (Scheme 1) [13].…”

“…In the original reaction, an aryl alkyl ketone or aryl aldehyde was reacted with sulfur and a primary or secondary amine, to give the terminal thioamide (Scheme 1) [13].…”