1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 08 ( s , 1 H ) , 9 . 05 ( s , 1 H ) , 8 . 31 ( d , J = 3 . 0 Hz , 1 H ) , 8 . 04 ( d , J = 3 . 0 Hz , 1 H ) , 7 . 86 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 77 ( d , J = 3 . 0 Hz , 1 H ) , 7 . 60 - 7 . 45 ( m , 3 H ) , 7 . 35 ( d , J = 15 . 0 Hz , 1 H ) , 6 . 11 ( m , 2 H ) , 5 . 67 ( dd , J = 32 . 6 , 5 . 2 Hz , 1 H ) , 3 . 53 ( s , 2 H ) , 2 . 52 - 2 . 43 ( m , 4 H ) , 2 . 41 - 2 . 26 ( m , 6 H ) , 2 . 13 ( s , 3 H ) . LR - MS ( ESI ) m / z 597 ( M + 1 ) .