1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 08 ( s , 1 H ) , 8 . 33 ( d , J = 3 . 0 Hz , 1 H ) , 8 . 06 ( d , J = 3 . 0 Hz , 1 H ) , 7 . 92 ( ddd , J = 17 . 9 , 15 . 0 , 6 . 4 Hz , 2 H ) , 7 . 60 - 7 . 48 ( m , 2 H ) , 7 . 37 ( d , J = 15 . 0 Hz , 1 H ) , 6 . 51 ( dd , J = 15 . 9 , 15 . 1 Hz , 1 H ) , 3 . 54 ( s , 2 H ) , 2 . 54 - 2 . 44 ( m , 4 H ) , 2 . 34 ( m , 6 H ) , 2 . 18 ( m , 3 H ) . LR - MS ( ESI ) m / z 546 ( M + 1 ) .