Aluminum Oxide Nanoparticle Promoted Synthesis of Substituted Coumarin-3-Carboxylic Acid

Coumarin-3-carboxylic acids (2-oxo-2H-benzopyran-3-carboxylic acids) are important initial compounds for the synthesis of coumarins, which are well known natural products for their diverse biological activities[1]. Coumarin-3-carboxylic acids are traditionally prepared via knoevenagel condensation of ortho-hydroxyarylaldehydes with malonic acid, malonic ester, or cyanoacetic ester. We report herein our results with nanosized aluminium oxide the efficiently catalyzed synthesis coumarin-3-carboxylic acids of 2-hydroxybenzaldehyde and Meldrum 's acid.Heterogeneous catalysts are advantageous over conventional homogeneous catalysts as they can be easily recovered from the reaction mixture by simple filtration and can be reused after activation, thereby making the process economically viable. Among the heterogeneous basic catalyst, aluminium oxide is a versatile material used as catalyst for several base-catalyzed organic transformations[2], toxic waste remediation, and as additive in refractory, paint, and superconductor products