1 H NMR ( DMSO - d 6 , 400 MHz ) δ 8 . 48 ( d , J = 9 . 0 Hz , 1 H ) , 6 . 74 ( d , J = 9 . 0 Hz , 1 H ) , 4 . 02 ( s , 3 H ) , 3 . 18 ( t , J = 7 . 4 Hz , 2 H ) , 1 . 75 - 1 . 65 ( m , 2 H ) , 1 . 42 - 1 . 35 ( m , 2 H ) , 1 . 3 - 1 . 2 ( m , 8 H ) , 0 . 86 - 0 . 83 ( m , 3 H ) ;