Collect. Czech. Chem. Commun.
2010, 75, 871-885
https://doi.org/10.1135/cccc2010012
Published online 2010-08-20 09:52:04
Synthesis and selected transformations of 3-oxido-1H-imidazole-4-carboxamides
Grzegorz Mloston and Marcin Jasiński*
Department of Organic and Applied Chemistry, University of Łódź, Tamka 12, PL-91-403 Łódź, Poland
Abstract
An efficient synthesis of new N-alkyl- and N-aryl-3-oxido-1H-imidazole-4-carboxamides based on exploration of inexpensive, commercially available ethyl acetoacetate, paraformaldehyde and primary amines is described. Representative compounds were tested in selected transformations, such as ‘sulfur-transfer reaction’ leading to imidazole-2-thiones and isomerization to corresponding imidazol-2-ones. Strong intramolecular hydrogen bonding via the N-oxide function results in the reduced reactivity of 3-oxido-1H-imidazole-4-carboxamides in both reactions. Moreover, the palladium catalyzed C(2)-arylation of imidazole ring as well as azide-alkyne [3+2] cycloaddition using the N-propargyl substituted 4-carboxamide derived from an imidazole 3-oxide as a dipolarophile, were also studied.
Keywords: Imidazole N-oxides; Carboxamides; Hydrogen bond; 1,3-Dipolar cycloaddition; Direct arylation.
References: 28 live references.
