1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 00 ( s , 1 H ) , 8 . 39 ( d , J = 3 . 0 Hz , 1 H ) , 8 . 03 ( d , J = 3 . 0 Hz , 1 H ) , 7 . 94 ( m , 2 H ) , 7 . 70 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 55 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 08 ( d , J = 15 . 0 Hz , 1 H ) , 6 . 81 ( d , J = 15 . 0 Hz , 1 H ) , 6 . 54 ( t , J = 15 . 0 Hz , 1 H ) , 3 . 97 - 3 . 70 ( m , 4 H ) , 2 . 63 - 2 . 33 ( m , 4 H ) , 2 . 30 ( s , 2 H ) , 2 . 23 - 2 . 03 ( m , 5 H ) , 2 . 02 - 1 . 85 ( m , 2 H ) . LR - MS ( ESI ) m / z 525 ( M + 1 ) .