Attempted syntheses of aminofluorothiophenes

It appeared that a key intermediate for 2-amino-3-fluorothiophene (1), meth yl 3-fluorothiophene-2-carboxylate (5), had been prepared by a Schiemann re action 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 abl e to prepare 5 by using special conditions for the Schiemann reaction. The hydrazide derivative of 5 failed to give 1 under Curtius reaction condition s. Two new acetamidofluorothiophene compounds were prepared using Selectflu or(TM) as the fluorinating agent, but no aminofluorothiophenes 1-3 or salts could be obtained by acidic hydrolysis of either amide.