Synthesis of some New Schiff Bases and Hydrazones Containing Benzonaphthyridine/ Benzonaphthyridone Moiety


The N-(4-methyl-2-pyridyl)anthranilic acid (I) was synthesized by Ullmann condensation. The compound (I) was cyclized by polyphosphoric acid (PPA) to give 4-methyl-10H-benzo[b][1,8]naphthyridin-5-one (II). The compound (II) was treated with selenium dioxide (SeO2) and thionyl chloride (SOCl2) to give the 4-formyl-10H-benzo[b][1,8]naphthyridin-5-one (III) and 4-methyl-5-chloro-benzo[b][1,8]naphthyridine (IV) respectively. The compound (III) was reacted with various substituted anilines and aliphatic amines to give the Schiff bases (Va-j). The compound (IV) was reacted with hydrazine hydrate to yield the 5-hydrazino derivative (VI), which was reacted with various aromatic aldehydes to yield the hydrazones (VIIa-j) and the Rf values reported.The reaction progress was followed by thin layer chromatography (TLC). The synthesized compounds were confirmed by spectral data (I.R, 1H-NMR, 13C-MNR). The possible fragmentation pattern of GC/MS for the compounds (III), (Vc) and (VIIg) were reported.