1 H NMR ( 400 MHz , CDCl 3 ) δ = 7 . 45 ( d , J = 8 . 8 Hz , 2 H ) , 7 . 29 ( d , J = 4 . 0 Hz , 1 H ) , 7 . 09 ( t , J = 8 . 8 Hz , 2 H ) , 6 . 91 ( d , J = 4 . 0 Hz , 1 H ) , 6 . 66 ( d , J = 4 . 0 Hz , 1 H ) , 6 . 58 ( d , J = 4 . 0 Hz , 1 H ) , 6 . 43 ( t , J = 6 . 0 Hz , 1 H ) , 4 . 89 - 4 . 83 ( m , 1 H ) , 4 . 11 ( t , J = 9 Hz , 1 H ) , 4 . 05 - 3 . 97 ( m , 2 H ) , 3 . 95 - 3 . 83 ( m , 4 H ) , 3 . 74 ( dt , J = 9 , 6 Hz , 1 H )