1 H NMR ( 300 MHz , DMSO - d 6 ) δ : 8 . 24 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 60 - 7 . 50 ( m , 4 H ) , 7 . 44 - 7 . 38 ( m , 4 H ) , 7 . 06 ( s , 1 H ) , 4 . 24 ( m , 1 H ) , 4 . 03 ( s , 3 H ) , 1 . 24 ( d , J = 6 . 8 Hz , 6 H ) .