Synthesis of acridinyl substituted amidoalkyl naphthols with pH-sensitive fluorescence activity

Acridine and its derivatives are heterocyclic analogues of anthracene that central ring containing nitrogen instead of a carbon atom. Acridine and some of its derivatives have interesting photophysical properties, i.e., high fluorescence quantum yield and high molar absorption coefficients.1-3 Synthesis of amidoalkyl naphthols is one of the most studied reactions because these compounds can be converted to useful and main biological building blocks, and their hydrolysis leads to 1-amino methyl-2-naphthols that show biological activities.4Herein, we wish to report the synthesis of new acridinyl substituted amidoalkyl naphthols 4 from the multicomponent reaction of acridinyl benzamide 1, 2-naphthol 2 and aromatic aldehydes 3 in the presence of p-toluene sulfonic acid as a catalyst (fig. 1). The structure of the synthesized compounds was determined on the basis of their spectroscopic data. These products have a strong fluorescence emission in pH = 7 while in acidic and basic pH the florescence emission of these compounds is quenched.

Keywords:

Multi-component reactions , Amidoalkyl naphthol , Acridine , Fluorescence