- 1 H NMR ( CDCl 3 , 500 MHz ) : δ 7 . 25 ( d , 4 H ) , 6 . 90 ( d , 4 H ) , 6 . 58 ( d , 2 H ) , 6 . 32 ( d , 2 H ) , 4 . 01 ( t , 4 H ) , 1 . 78 ( m , 4 H ) , 1 . 52 ( m , 4 H ) , 0 . 99 ( t , 6 H )