1 H NMR ( 400 MHz , CDCl 3 ) δ 7 . 77 ( d , J = 1 . 2 Hz , 1 H ) , 7 . 67 ( d , J = 2 . 4 Hz , 1 H ) , 7 . 48 ( s , 1 H ) , 7 . 47 ( d , J = 0 . 8 Hz , 1 H ) , 7 . 38 ( dd , J = 1 . 8 , 8 . 6 Hz , 1 H ) , 7 . 31 ( s , 1 H ) , 7 . 05 ( ddd , J = 4 . 3 , 13 . 2 Hz , 1 H ) , 6 . 78 ( dd , J = 1 . 0 , 2 . 2 Hz , 1 H ) , 6 . 62 ( m , 1 H ) , 6 . 46 ( m , 1 H ) , 6 . 38 ( ddd , J = 2 . 3 , 10 . 7 Hz , 1 H ) .