1 H NMR ( CDCl 3 , 300 MHz ) δ 3 . 00 ( t , 4 H , J = 4 . 2 Hz ) , 3 . 52 9 t , 4 H , J = 3 . 9 Hz ) , 5 . 43 ( s , 2 H ) , 6 . 91 ― 6 . 97 ( m , 2 H ) , 7 . 04 ( s , 2 H ) , 7 . 28 ― 7 . 34 ( m , 4 H ) , 7 . 42 ( s , 2 H ) , 7 . 49 ( s , 2 H ) , 8 . 56 ( s , 1 H ) .