ChemInform Abstract: Unambiguous Synthesis of 1-Methyl-3-hydroxypyrazoles.

✍ Scribed by D. ZIMMERMANN; P. KROGSGAARD-LARSEN; J.-D. EHRHARDT; U. MADSEN; Y. L. JANIN

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 33 KB
• Volume: 29
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199846137

✦ Synopsis

Unambiguous Synthesis of 1-Methyl-3-hydroxypyrazoles.

-A new method for the preparation of title compounds (VIII) includes the use of bicyclic heterocycles (V) as intermediates, which are prepared by cyclization of tosyl derivatives (IV) via a nitrogen to oxygen transfer of the tosyl group. The final iodine-based oxidative deprotection of the intermediate iodoethyl derivatives derived from vinyl compounds (VII) gives better yields of target compounds (VIIIa) and (VIIIc) as does acidic hydrolysis.

-(ZIMMERMANN, D.;