1 H NMR ( 400 MHz , CDCl 3 ) δ 8 . 48 ( s , 1 H ) , 7 . 90 ( d , J = 9 . 0 Hz , 1 H ) , 7 . 81 ( d , J = 2 . 0 Hz , 1 H ) , 7 . 41 ( dd , J = 8 . 8 , 2 . 3 Hz , 1 H ) , 4 . 29 - 4 . 16 ( m , 1 H ) , 3 . 95 ( br s , 2 H ) , 3 . 86 ( br d , J = 11 . 0 Hz , 1 H ) , 3 . 19 - 2 . 96 ( m , 3 H ) , 2 . 61 ( ddd , J = 9 , 7 , 2 Hz , 1 H ) , 2 . 41 ( s , 3 H ) .