1 H - NMR ( 500 MHz , CDCl 3 , δ ) : 7 . 98 ( d , J = 1 . 0 Hz , 2 H ) , 7 . 85 ( d , J = 1 . 0 Hz , 2 H ) , 7 . 73 ( d , J = 2 . 0 Hz , 2 H ) , 7 . 60 - 7 . 58 ( m , 6 H ) , 7 . 49 - 7 . 44 ( m , 12 H ) , 7 . 39 - 7 . 24 ( m , 20 H ) , 7 . 19 - 7 . 16 ( m , 4 H ) , 7 . 12 - 7 . 09 ( m , 2 H ) , 7 . 05 - 6 . 97 ( m , 6 H ) , 6 . 93 ( d , J = 8 . 0 Hz , 2 H ) , 6 . 64 ( t , J = 8 . 0 Hz , 1 H ) , 6 . 58 ( t , J = 8 . 0 Hz , 2 H )