1 H NMR ( 400 MHz , CD 3 OD ) δ 7 . 67 ( dd , J = 1 . 5 , 7 . 7 Hz , 4 H ) , 7 . 45 - 7 . 37 ( m , 6 H ) , 3 . 76 ( t , J = 6 . 2 Hz , 2 H ) , 3 . 17 ( t , J = 6 . 2 Hz , 2 H ) , 1 . 44 ( s , 9 H ) , 1 . 04 ( s , 9 H )