Synthesis of Naphthindol-6(2H)-one Derivatives and Their Fluorescence Properties

Article abstract of DOI:10.1246/bcsj.64.3417

Highly fluorescent 1-phenylnaphth<1,2,3-cd>indol-6(2H)-one (3b) and its 7-chloro and 7-amino derivatives were synthesized by reaction of 1-aminoanthraquinone with benzyl chloride in KOH-DMSO system, followed by treatment with aluminium chloride.The compound 3b was easily N-alkylated with various alkyl halides in KOH-DMSO system.The fluorescence quantum yields (Φ_f) of naphth<1,2,3-cd>indol-6(2H)-one derivatives 3 were high (0.5-0.7), except for 7-amino derivatives which did not fluoresce.The Φ_f of 7-chloro derivative (3d) was strongly dependent on solvent: 0.37 in ethanol; 0.02 in acetonitrile; 0 in benzene.The compounds 3 were demonstrated to be efficient laser dyes for 500-550 nm region.