Efficient Synthesis of Functionalized Benzo[b][1,8]naphthyridine Derivatives via Three-Component Reaction Catalyzed by L-Proline

A facile and efficient one-pot procedure for the preparation of functionalized benzo[b][1,8]naphthyridine derivatives by three-component reaction of 2-chloroquinoline-3-carbaldehyde, 1,3-dicarbonyl compounds, and enaminones catalyzed by L-proline is described. This new protocol has the advantages of environmental friendliness, good yields, and convenient operation.