Novel Fluorophores based on Regioselective Intramolecular Friedel–Crafts Acylation of the Pyrene Ring Using Triflic Acid

The extension of the pyrene ring from dimethyl 2,2′-(pyrene-1,6-diyl)dibenzoate derivatives by an intramolecular Friedel–Crafts acylation can be realized in an efficient and regioselective manner using triflic acid as proton source. Naphtho-tetracenone derivatives are obtained in high yields at room temperature while Bis-tetracene-diones are prepared upon heating. Both products display interesting fluorescence properties in the visible range with quantum yields varying from 50 to 60 %.