Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5273423 | Tetrahedron Letters | 2012 | 4 Pages |
Abstract
Indazolones are medicinally relevant targets. Herein we disclose an improved synthesis to Nâ²-(acetamido-2-yl)-substituted indazolones with four points of diversity introduced by Ugi-[M]-amination and -amidation. The ring closure can be achieved by either conventional palladium catalysis or with a ligandless copper protocol. When α-unbranched isocyanides were employed the sole cyclization products of the copper catalyzed reactions are the hitherto undescribed 2-hydroxy-3H-3,4a,9a-triaza-fluorene-4,9-diones.
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Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Sebastian J. Welsch, Cédric Kalinski, Michael Umkehrer, Günther Ross, Jürgen Kolb, Christoph Burdack, Ludger A. Wessjohann,