Carbon-based solid sulfonic acid catalyzed oxidative benzannulation to construct alkylamino-benzocoumarin

The facile synthetic approach of coumarin derivatives has been described through Michael addition/cyclization/oxidative benzannulation using carbon-based solid sulfonic acid as the sustainable catalyst. The reaction proceeds in good to excellent yields in one-step from hydroxy-substituted chalcone, ethyl acetoacetate and amine. The utility of this transformation has been highlighted by its use for the construction of alkylaminobenzocoumarin, which was a new coumarin fluorescent molecular. [Display omitted]