1 H NMR ( CD 3 OD , 400 MHz ) δ 8 . 53 ( s , 1 H ) , 8 . 25 ( s , 1 H ) , 8 . 03 ( d , J = 9 . 4 Hz , 1 H ) , 7 . 52 ( d , J = 8 . 5 Hz , 2 H ) , 7 . 36 ( d , J = 8 . 5 Hz , 2 H ) , 7 . 19 ( t , J = 7 . 9 Hz , 4 H ) , 7 . 10 - 7 . 04 ( m , 3 H ) , 6 . 96 - 6 . 92 ( m , 3 H ) , 3 . 94 ( s , 3 H ) , 3 . 85 ( s , 3 H ) , 3 . 81 ( s , 3 H ) , 3 . 75 ( s , 3 H ) , 2 . 48 ( s , 3 H ) .