1 H NMR ( CD 3 OD , 400 MHz ) δ 8 . 62 ( s , 1 H ) , 8 . 40 ( s , 1 H ) , 8 . 02 ( d , J = 8 . 6 Hz , 1 H ) , 7 . 76 ( t , J = 7 . 6 Hz , 1 H ) , 7 . 63 ( s , 5 H ) , 7 . 55 ( d , J = 8 . 2 Hz , 1 H ) , 7 . 48 ( s , 5 H ) , 7 . 41 ( t , J = 7 . 6 Hz , 1 H ) , 7 . 35 - 7 . 32 ( m , 3 H ) , 7 . 28 ( d , J = 7 . 2 Hz , 2 H ) , 2 . 51 ( s , 3 H ) .