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Short Paper | Regular issue | Vol 92, No. 9, 2016, pp.1698-1705
Published online, 12th July, 2016
DOI: 10.3987/COM-16-13510
KH2PO4 Promoted Practical and Environmentally Friendly Preparation of Coumarin-3-carboxylic Acids under Solvent-Free Condition

Shuangqiu Gao, Di Xiao, Ying Yang, Xiaoyü Wei, Sai Sun, Jian Lang, and Chengwei Lv*

*School of Chemistry and Chemical Engineering, Liaoning Normal University, No.850 Huanghe Road, Liaoning Province 116029, China

Abstract

An efficient and green protocol for synthesis of coumarin-3-carboxylic acids is developed in good to high yields via a Knoevenagel-intramolecular cyclization cascade reaction of Meldrum’s acid with various ortho-hydroxyarylaldehydes. This reaction is catalyzed by a combination of KH2PO4 (10 mol%) and water (100 μL). Solvent-free, cheap and eco-friendly catalyst, clean reaction conditions, simple workup procedure and easy isolation are the best features in this process.