1 H NMR ( 300 MHz , CDCl 3 ) δ 4 . 00 ( dt , 2 H , J = 5 . 7 , 1 . 2 Hz ) , 4 . 18 ( s , 3 H ) , 4 . 23 ( dd , 2 H , J = 6 . 6 , 1 . 5 Hz ) , 4 . 50 ( dt , 2 H , J = 5 . 7 , 1 . 2 Hz ) , 5 . 16 - 5 . 34 ( m , 4 H ) , 5 . 89 - 5 . 97 ( m , 2 H ) , 6 . 11 ( ddt , 1 H , 17 . 4 , 11 . 1 , 5 . 7 Hz ) , 6 . 72 ( d , 1 H , J = 2 . 1 Hz ) , 6 . 83 ( d , 1 H , J = 11 . 7 Hz ) , 7 . 05 ( s , 1 H ) , 7 . 60 ( d , 1 H , J = 2 . 1 Hz )