1 H - NMR ( 500 MHz , CDCl 3 , δ ) : 8 . 16 ( d , J = 7 . 5 Hz , 4 H ) , 7 . 62 - 7 . 59 ( m , 2 H ) , 7 . 54 - 7 . 49 ( m , 7 H ) , 7 . 38 ( dt , J = 7 . 5 Hz , 1 . 0 Hz , 4 H ) , 7 . 30 ( d , J = 7 . 5 Hz , 4 H )