1 H NMR ( 400 MHz , CDCl 3 ) δ 8 . 67 ( ddd , J = 4 . 7 , 1 . 7 , 0 . 9 Hz , 1 H ) , 8 . 27 ( dt , J = 7 . 9 , 1 . 0 Hz , 1 H ) , 8 . 24 ( d , J = 8 . 4 Hz , 1 H ) , 8 . 06 ( td , J = 7 . 8 , 1 . 7 Hz , 1 H ) , 7 . 70 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 59 ( ddd , J = 7 . 7 , 4 . 7 , 1 . 1 Hz , 1 H ) ;