Synthesis of 1‐substituted 3‐nitroquinolin‐4(1 H )‐ones

A versatile synthetic method for preparing 1‐substituted 3‐nitroquinolin‐4(1 H )‐ones from corresponding 2‐fluoro‐α‐nitroacetophenones is demonstrated by the synthesis of 6,7‐difluoro derivatives 7a‐c . The method involves sequential treatment of the starting nitroacetophenone with triethyl orthoformate and the appropriate amine, followed by a nucleophilic cyclization reaction under mild conditions. The C‐7 fluorine atom of 7 can be displaced by cyclic amines. Substituted 6‐fluoro‐7‐(4‐methyl‐1‐piperazinyl)‐3‐nitroquinolin‐4(1 H )‐ones 8a‐c were prepared in this way.