7-Chloro-4-methyl-6-nitro-2H-chromen-2-one: a novel type of reagent for fluorescence analysis

Starting from 7-chloro-4-methyl-2H-chromen-2-one 1 we have obtained a new reagent for fluorescence analysis. The synthesised key compound 7-chloro-4-methyl-6-nitro-2H-chromen-2-one 2 forms highly fluorescent derivatives with different amines, which can be introduced by nucleophilic substitution of the chloro atom. Two examples are given which describe the preparation of these derivatives. Additionally, we demonstrate that an increase of fluorescence can be achieved, if a reduction step is performed after the substitution.