1 H NMR ( CD 3 OD , 400 MHz ) δ 8 . 71 ( s , 1 H ) , 8 . 40 ( s , 1 H ) , 8 . 02 ( d , J = 8 . 6 Hz , 1 H ) , 7 . 77 ( t , J = 7 . 7 Hz , 1 H ) , 7 . 64 - 7 . 61 ( m , 6 H ) , 7 . 43 - 7 . 38 ( m , 3 H ) , 7 . 20 ( d , J = 8 . 3 Hz , 2 H ) , 7 . 06 ( d , J = 8 . 4 Hz , 2 H ) , 6 . 94 ( d , J = 8 . 4 Hz , 2 H ) , 3 . 85 ( s , 3 H ) , 3 . 81 ( s , 3 H ) , 2 . 55 ( s , 3 H ) .