1 H NMR ( 300 MHz , DMSO ) δ 8 . 35 ( d , J = 8 . 4 Hz , 1 H ) , 8 . 24 ( d , J = 7 . 8 Hz , 1 H ) , 8 . 11 ( t , J = 8 . 1 Hz , 1 H ) , 7 . 27 ( d , J = 7 . 5 Hz , 1 H ) , 7 . 08 ( d , J = 7 . 5 Hz , 1 H ) , 5 . 89 - 5 . 80 ( m , 1 H ) , 4 . 39 - 4 . 31 ( m , 1 H ) , 4 . 22 - 4 . 12 ( m , 3 H ) , 3 . 76 ( s , 3 H ) , 3 . 09 ( s , 3 H ) , 1 . 18 ( t , J = 7 . 2 Hz , 3 H ) .