One-pot synthesis of dibenzo[b,h][1,6]naphthyridines from 2-acetylaminobenzaldehyde: application to a fluorescent DNA-binding compound

Dibenzo[b,h][1,6]naphthyridines were synthesized in one pot by reacting 2-acetylaminobenzaldehyde with methyl ketones under basic conditions via four sequential condensation reactions. This method was also applied to the synthesis of 1,2-dihydroquinolines. 6-Methyl-1,6-dibenzonaphthyridinium triflates showed strong fluorescence, and the fluorescence intensities were changed upon intercalation into double-stranded DNA.