One‐pot, three‐component synthesis of polyfunctionalized benzo[ h ]pyrazolo[3,4‐ b ][1,6]naphthyridine and benzo[ g ]pyrazolo[3,4‐ b ]quinoline derivatives in the presence of silver nanoparticles ( AgNPs )

An efficient and straightforward protocol for one‐pot, three‐component reaction of aryl glyoxal monohydrates 1a‐h , 5‐amino‐1‐aryl‐3‐methylpyrazoles 2a , b and 4‐hydroxyquinoline‐2(1 H )‐one ( 3 ) or 2‐hydroxy‐1,4‐naphthoquinone ( 4 ) using silver nanoparticles (AgNPs) as a high performance nanocatalyst in H 2 O/EtOH at 60°C afforded the corresponding polyfunctionalized benzo[ h ]pyrazolo[3,4‐ b ][1,6]naphthyridines 5a‐h and benzo[ g ]pyrazolo[3,4‐ b ]quinolines 6a‐i , respectively. Excellent catalytic activity, high yields, employing green media and green nanocatalyst, cost‐effective and simple procedure are some notable advantages of using AgNPs as a noble metal nanocatalyst in this synthetic strategy. The structures of fused heterocycles were confirmed by their Fourier transform infrared, proton nuclear magnetic resonance ( 1 H‐NMR), and 13 C‐NMR spectral data and microanalysis.