A Concise Synthesis of Fluorine-Containing Benzo[h]quinolines and Benzo[h]quinolones by Selective Pyridine and Pyridinone Rings Formation Reactions of N-Propargyl-2,4-bis(trifluoroacetyl)-1-naphthylamine with Various Active Methylene Compounds

Abstract

N-Propargyl-2,4-bis(trifluoroacetyl)-1-naphthylamine (3) underwent nitrogen-containing heterocyclic ring-formation reactions with a variety of active methylene compounds in the presence of sodium alkoxides. This annulation reactions with dialkyl malonates were highly dependent on reaction temperature to give selectively the corresponding fluorine-containing benzo[h]quinolines (5) at high temperature and 1H-benzo[h]quinolin-2-ones (7 and 8) at low temperature. Furthermore, changing the electron-withdrawing groups of active methylene compounds led to alternation of the reactive site wherein the reagents attack first and to the formation of the different nitrogen-containing heterocyclic systems, pyridine (9), dihydropyridine (11 and 13) and pyridone (12).