“…[1][2][3][4] They show diverse biological and pharmacological activities ranging from antimicrobial, anti-arrhythmic, antitumor, antifungal, anti-HIV, anti-osteoporosis to anti-inflammatory. [5][6][7][8][9][10][11][12] Apart from their pharmaceutical applications, [13][14] coumarins have been used as additives in foods, perfumes and cosmetics as well as in the preparation of optical brighteners, laser dyes, fluorescent labels and nonlinear optical chromophores. [15][16][17][18][19] The Pechmann reaction 20 is known as one of the most valuable methods for the synthesis of coumarins since it proceeds from simple starting materials, a phenol and a -keto ester, together with an acid catalyst.…”