Synthesis and antioxidant activity of novel 8-formyl-4-substitued coumarins

4-Methyl-8-formyl- and 4-phenyl-8-formyl coumarins have been synthesized by Pechmann reaction using oxalic acid catalyst for the first time. 4-Propyl-7-hydroxy-, and 4-methyl-7-methoxy coumarins have also been accomplished by this catalyst for the first time. They have been characterizated by IR, 1H-NMR, 13C-NMR, mass and elemental analysis. Furthermore, the obtained coumarins were compared according to antioxidant activity by DPPH method.