1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 11 ( s , 1 H ) , 8 . 27 ( t , J = 3 . 0 Hz , 1 H ) , 8 . 06 ( d , J = 3 . 0 Hz , 1 H ) , 7 . 97 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 84 ( dt , J = 8 . 0 , 3 . 0 Hz , 2 H ) , 7 . 70 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 56 ( dd , J = 15 . 0 , 3 . 0 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 . 52 - 2 . 44 ( m , 4 H ) , 2 . 42 - 2 . 26 ( m , 4 H ) , 2 . 21 ( s , 2 H ) , 2 . 18 ( s , 3 H ) . LR - MS ( ESI ) m / z 528 ( M + 1 ) .