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Attempted syntheses of aminofluorothiophenes
Author(s) -
Kobarfard Farzad,
Kauffman Joel M.,
Boyko Walter J.
Publication year - 1999
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570360522
Subject(s) - chemistry , hydrazide , curtius rearrangement , amide , hydrolysis , derivative (finance) , salt (chemistry) , organic chemistry , carboxylate , economics , financial economics
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.