1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 06 ( s , 1 H ) , 8 . 67 ( t , J = 3 . 0 Hz , 1 H ) , 8 . 55 ( t , J = 3 . 0 Hz , 1 H ) , 8 . 21 - 8 . 01 ( m , 2 H ) , 7 . 97 ( dd , J = 14 . 9 , 3 . 1 Hz , 1 H ) , 7 . 70 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 56 ( dd , J = 14 . 9 , 2 . 9 Hz , 1 H ) , 7 . 37 ( d , J = 15 . 0 Hz , 1 H ) , 6 . 54 ( t , J = 15 . 0 Hz , 1 H ) , 3 . 54 ( s , 2 H ) , 2 . 54 - 2 . 43 ( m , 4 H ) , 2 . 38 - 2 . 28 ( m , 4 H ) , 2 . 15 ( s , 2 H ) , 2 . 13 ( s , 3 H ) . LR - MS ( ESI ) m / z 519 ( M + 1 ) .