An efficient one-pot synthesis of highly substituted [1,8]naphthyridin-1-phenyl-1-ethanone derivatives via a four-component reaction

Abstract

An operationally simple one-pot protocol for the synthesis of highly substituted [1,8]naphthyridin-1-phenyl-1-ethanones dealing with 2-chloroquinoline-3-carbaldehyde and 1-phenyl-2-(1,1,1-triphenyl-λ 5-phosphanylidene)ethan-1-one, 1,1-bis(methylthio)-2-nitroethylene or ketene N,S-acetals, and aromatic/aliphatic amine or diamines under mild and catalyst-free conditions in excellent yields is described. The structures of products were corroborated spectroscopically (IR, 1H- and 13C-NMR, and EI-MS) and by X-ray analysis. An efficient, useful and general procedure for the synthesis of [1,8]naphthyridin-1-phenyl-1-ethanones via a one-pot four-component reaction of 2-chloroquinoline-3-carbaldehyde and 1-phenyl-2-(1,1,1-triphenyl-λ 5-phosphanylidene)ethan-1-one, 1,1-bis(methylthio)-2-nitroethylene or ketene N,S-acetals, and aromatic/aliphatic amine or diamines under mild and catalyst-free conditions in excellent yields is described. The major advantages of this protocol are high yields, mild and catalyst-free conditions, short reaction times, and application of green solvent.