1 H NMR ( CD 3 OD , 400 MHz ) δ 8 . 84 ( s , 1 H ) , 8 . 39 ( s , 1 H ) , 8 . 01 ( d , J = 8 . 6 Hz , 1 H ) , 7 . 77 ( t , J = 7 . 6 Hz , 1 H ) , 7 . 66 - 7 . 60 ( m , 6 H ) , 7 . 41 ( t , J = 7 . 6 Hz , 1 H ) , 7 . 30 ( d , J = 8 . 2 Hz , 2 H ) , 7 . 18 ( d , J = 8 . 3 Hz , 2 H ) , 7 . 12 ( d , J = 8 . 2 Hz , 2 H ) , 6 . 70 ( d , J = 8 . 3 Hz , 2 H ) , 2 . 96 ( s , 3 H ) , 2 . 81 ( s , 3 H ) , 2 . 56 ( s , 3 H ) .