The synthesis of difluoro[1]benzothieno[2,3‐ c ]quinolines and their N ‐methyl quaternary salts

A series of difluoro[1]benzothieno[2,3‐ c ]quinolines has been prepared by photocyclization of the appropriate carboxamides. The lactams obtained were converted into the corresponding chloro derivatives which were catalytically dechlorinated into the difluoro[1] benzothieno[2,3‐ c ]quinolines. The latter compounds were transformed into the N ‐methyl quaternary salts.