1 H - NMR ( 500 MHz , Methylene Chloride - d 2 ) : δ 8 . 8 ( d , 2 H ) , 8 . 3 ( s , 1 H ) , 8 . 4 ( t , 1 H ) , 8 . 2 ( t , 2 H ) , 7 . 8 ( m , 2 H ) , 7 . 6 ( m , 6 H ) , 7 . 3 ( t , 2 h ) , 6 . 7 ( s , 1 H ) .