Microwave-Assisted Synthesis and Antifungal Activities of Polysubstituted Furo[3,2-c]chromen-4-ones and 7,8,9,10-Tetrahydro-6H-benzofuro[3,2-c]chromen-6-ones

An efficient and novel microwave-assisted synthesis of furo3,2-c]chromen-4-ones and 7,8,9,10-tetrahydro-6H-benzofuro3,2-c]chromen-6-ones via 4-hydroxycoumarins with α-chloroketones or α-bromocyclohexanone in the presence of acetic acid (AcOH)/ammonium acetate (NH₄OAc) using DMF as solvent under microwave irradiation is described. Systematically, antifungal biological tests showed that most of the compounds exhibited potent antifungal activity against Botrytis cinerea, Collecterichum capsica, Alternaria solani, Gibberella zeae, and Rhizoctorzia solani at the concentration of 50 µg/mL. The corresponding EC50 values of these analogues have been detected, and compound 4i showed better antifungal activity against tested fungi Botrytis cinerea and Collecterichum capsica than the reference Osthol.