1 H NMR ( 300 MHz , DMSO - d 6 ) δ : 8 . 07 ( d , J = 7 . 7 Hz , 2 H ) , 7 . 86 ( t , J = 7 . 7 Hz , 1 H ) , 7 . 74 ( t , J = 7 . 6 Hz , 1 H ) , 4 . 56 - 4 . 54 ( m , 1 H ) , 3 . 99 ( s , 3 H ) , 1 . 46 ( d , J = 6 . 8 Hz , 6 H ) .