1 H NMR ( CDCl 3 ) : δ 7 . 79 ( d , J = 7 . 5 Hz , 2 H , ArH ) , 7 . 73 ( d , J = 8 . 1 Hz , 2 H , ArH ) , 7 . 58 ～ 7 . 44 ( m , 3 H , ArH ) , 7 . 28 ( d , J = 8 . 4 Hz , 2 H , ArH ) , 2 . 44 ( s , 3 H , - CH 3 )