1 H NMR ( 400 MHz , CDCl 3 ) δ = 7 . 53 ( s , 1 H ) , 7 . 37 - 7 . 31 ( m , 4 H ) , 7 . 31 - 7 . 26 ( m , 1 H ) , 7 . 19 ( t , J = 8 Hz , 1 H ) , 6 . 88 ( d , J = 4 . 4 Hz , 1 H ) , 6 . 81 ( d , J = 8 . 8 Hz , 2 H ) , 6 . 81 - 6 . 74 ( br , 1 H ) , 4 . 87 - 4 . 79 ( m , 1 H ) , 4 . 13 - 3 . 97 ( m , 5 H ) , 3 . 87 ( ddd , J = 14 . 8 , 6 . 4 , 3 . 2 Hz , 1 H ) , 3 . 80 ( dd , J = 9 . 2 , 6 . 4 Hz , 1 H ) , 3 . 70 ( dt , J = 14 . 8 , 6 Hz , 1 H )