1 H NMR ( 400 MHz , CDCl 3 ) δ 8 . 59 ( s , 1 H ) , 8 . 24 ( d , J = 1 . 8 Hz , 1 H ) , 8 . 03 ( d , J = 8 . 8 Hz , 1 H ) , 7 . 60 ( dd , J = 8 . 8 , 1 . 8 Hz , 1 H ) , 4 . 32 - 4 . 19 ( m , 1 H ) , 4 . 09 - 3 . 96 ( m , 3 H ) , 3 . 18 - 2 . 97 ( m , 3 H ) , 2 . 64 ( ddd , J = 9 . 7 , 6 . 6 , 1 . 8 Hz , 1 H ) , 2 . 41 ( s , 3 H ) .