1 H NMR ( 300 MHz , CDCl 3 ) δ 4 . 16 ( s , 3 H ) , 4 . 53 ( dt , 2 H , J = 5 . 7 , 1 . 2 Hz ) , 4 . 59 ( dt , 2 H , J = 5 . 7 , 1 . 2 Hz ) , 5 . 16 - 5 . 39 ( m , 4 H ) , 5 . 94 ( ddt , 1 H , J = 15 . 9 , 10 . 5 , 5 . 7 Hz ) , 6 . 03 ( d , 1 H , J = 12 . 6 Hz ) , 6 . 15 ( ddt , 1 H , J = 15 . 9 , 10 . 5 , 5 . 7 Hz ) , 6 . 71 ( d , 1 H , J = 2 . 4 Hz ) , 7 . 27 ( d , 1 H , J = 12 . 6 Hz ) , 7 . 57 ( d , 1 H , J = 2 . 4 Hz ) , 7 . 59 ( s , 1 H )