1 H - NMR ( 500 MHz , Methylene Chloride - d 2 ) : δ 8 . 8 ( d , 2 H ) , 8 . 5 ( s , 1 H ) , 8 . 6 ( t , 1 H ) , 8 . 2 ( t , 2 H ) , 7 . 9 ( m , 2 H ) , 7 . 8 ( m , 2 H ) , 7 . 6 ( m , 5 H ) , 7 . 4 ( t , 1 h ) , 7 . 2 ( t , 1 H )