Synthesis of novel benzo[h][1,6]naphthyridine derivatives from 4-aminoquinoline and cyclic β-ketoester

This paper describes the synthesis of 2,8-dichloroquinolin-4-amine 4 and 4,5,7-trichloro-3-(2-chloroethyl)-2-methylbenzo[h][1,6]naphthyridine 8 as novel class of building blocks. Also describes the regioselective SNAr reactions of 2,4,8-trichloroquinoline 2 on C2 and C4 positions with azide, similarly SNAr reactions of benzo[h][1,6]naphthyridine 8 at C4, C5 positions, and SN2 reactions on C3-(2-chloroethyl) side chain with nucleophiles such as primary aromatic amines, methoxide/ethoxide, and azide at different temperatures.