Coumarin-3-carboxylic acid (2- Oxochromene-3-carboxylic acid) is an important initial compound for the synthesis of coumarins which are well known natural products for their diverse biological activities. Lanthanide complexes of Coumarin-3-carboxylic acid exhibit antiproliferative activity towards K-562 cell line[1][2].
[1]. Aimin Song, et al. A convenient synthesis of coumarin-3-carboxylic acids via Knoevenagel condensation of Meldrum's acid with ortho-hydroxyaryl aldehydes or ketones. Tetrahedron Letters. 2003 Feb;44(9): 1755-1758. [2]. Kostova I, et al. New Samarium(III), Gadolinium(III), and Dysprosium(III) Complexes of Coumarin-3-Carboxylic Acid as Antiproliferative Agents. Met Based Drugs. 2007;2007:15925.