Umlagerungen von Heterocyclen, VII. Ketenoide Umlagerung von 2-Pyronen zu Naphthalin-Derivaten

✍ Scribed by Kappe, Thomas ;Schmidt, Heinrich

• Publisher: Wiley (John Wiley & Sons)
• Year: 1979
• Tongue: English
• Weight: 339 KB
• Volume: 112
• Category: Article
• ISSN: 0009-2940
• DOI: 10.1002/cber.19791120745

✦ Synopsis

Rearrangement Reactions of Heterocycles, VII. Ketenoid Rearrangement of 2‐Pyrones to Naphthalenes

4‐Hydroxy‐2‐pyrones 3, obtained by the condensation reaction of trichlorophenyl malonates 1 with the ketones 2 at 240°C, are rearranged at 260°C via ketenes 6 to yield 1,3‐dihydroxynaphthalenes 5. The latter are readily oxidized to naphthoquinones 4 by air. A side product in the rearrangement of 3b is triphenylphloroglucinol (7).