Abstract
An efficient and selective multicomponent oxidative coupling, involving the use of
two different amines, sodium phosphate, and elemental sulfur have been described for
the preparation of thioamides, employing microwave irradiation. The use of an iron(III)-based
imidazolium salt is essential as catalyst. Indeed, the iron-based catalyst is involved
in the oxidative coupling of the two amines and in the subsequent C–S bond formation.
The protocol is useful for a wide variety of primary benzylamines and alkylamines,
as coupling partners. Thus, various electron-rich and electron-poor substituents in
the aromatic rings and also fused piperidine derivatives, are suitable starting materials
in this reaction. Some of the obtained products are important synthetic intermediates
for natural products.
Key words
imidazolium salt - ionic liquid - iron(III) catalyst - sulfur - thioamides
