Synthesis of new 4‐quinolone‐type compounds in the benzo[b]thiophene series

Some new derivatives of 1,4‐dihydro‐4‐oxo‐3‐pyridinecarboxylic acid (quinolone‐type compounds) 5 and 13 have been prepared in the benzo[b]thiophene series. The key step was the construction of the pyridine ring starting from 2‐aminobenzo[b]thiophene derivatives. The synthesis of amine 9, was performed by using an original “animation” reaction.