Synthese von 1‐Hydroxyimidazolen und 1‐Hydroxyimidazol‐3‐oxiden

Abstract

a-Hydroxyimino-P-diketone sowie a-Hydroxyimino-P-ketocarbonsaureester und -amide reagieren mit Aldehyden und Ammoniak zu den 1 -Hydroxyimidazolen 3. Mit Aldoximen entstehen die I-Hydroxyimidazol-3-oxide 4.Synthesis of 1-Hydroxyimidazoles and I-Hydroxyimidazole 3-Oxides* *) or-Hydroxyimino-P-diketones and cr-hydroxyimino-P-keto carboxylic acid esters and amides react with aldehydes and ammonia to form the 1-hydroxyimidazoles 3. Reaction with aldoximes leads to the 1-hydroxyimidazole 3-oxides 4.a-(Hydroxyimino)ketone setzen sich mit Aldehyden und Ammoniak zu 1-Hydroxyimidazolen (Imidazol-3-oxiden) 1 um1-4). Verwendet man Aldoxime anstelle von Aldehyden und Ammoniak, so entstehen die 1 -Hydroxyimidazol-3-oxides-7) 2. Die Verbindungen 1 und 2 fallen oft als Hydrate an, lassen sich aber in den meisten Fallen durch Umkristallisieren aus wasserfreien Losungsmitteln dehydratisieren.

Synthesis of 2-Substituted 1-Hydroxyimidazoles through Directed Lithiation

“…1-Hydroxyimidazoles − are useful intermediates for the preparation of pharmaceuticals and agricultural chemicals. They are usually obtained by condensation of monooximes of 1,2-diketones with ammonia and an aldehyde − or with an aldimine or by reaction of olefins and nitrosyl hydrogen sulfate in the presence of aliphatic nitriles. − 1-Hydroxyimidazoles have been obtained by selective reduction of 3-hydroxyimidazole 1-oxide. , prepared by cyclization of a 1,2-diketone, an aldehyde, and hydroxylamine.…”