1 H NMR ( 500 MHz , CDCl 3 , δ ) : 7 . 77 ( d , J = 1 . 2 , 2 H ) , 7 . 55 - 7 . 69 ( m , 4 H ) , 7 . 60 ( d , J = 7 . 5 Hz , 2 H ) , 7 . 51 ( dd , J = 8 . 5 Hz , 4 H ) , 7 . 42 ( td , J = 8 . 0 , J = 2 . 0 , 4 H ) , 7 . 32 - 6 . 94 ( m , 24 H ) , 6 . 75 ( d , J = 7 . 5 , 2 H ) , 6 . 55 ( td , J = 7 . 51 , J = 1 . 2 , 1 H ) , 6 . 46 ( t , J = 7 . 5 , 2 H )