Attempted syntheses of aminofluorothiophenes

✍ Scribed by Farzad Kobarfard; Joel M. Kauffman; Walter J. Boyko

• Book ID: 102342388
• Publisher: Journal of Heterocyclic Chemistry
• Year: 1999
• Tongue: English
• Weight: 358 KB
• Volume: 36
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570360522

✦ Synopsis

Abstract

It appeared that a key intermediate for 2‐amino‐3‐fluorothiophene (1), methyl 3‐fluorothiophene‐2‐carboxylate (5), had been prepared by a Schiemann reaction of the 3‐diazonium salt (6) in xylenes. This report was not correct. Gomberg coupling products 7 with o‐xylene are actually formed. We were able to prepare 5 by using special conditions for the Schiemann reaction. The hydrazide derivative of 5 failed to give 1 under Curtius reaction conditions. Two new acetamidofluorothiophene compounds were prepared using Selectfluor^TM^ as the fluorinating agent, but no aminofluorothiophenes 1‐3 or salts could be obtained by acidic hydrolysis of either amide.