1 H NMR ( 400 MHz , DMSO ) δ 8 . 33 ( d , 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 . 88 ( dd , J = 15 . 0 , 3 . 0 Hz , 1 H ) , 7 . 79 - 7 . 46 ( m , 3 H ) , 7 . 31 ( d , J = 15 . 0 Hz , 1 H ) , 6 . 89 ( s , 2 H ) , 6 . 53 ( t , J = 15 . 0 Hz , 1 H ) , 3 . 54 ( s , 2 H ) , 2 . 61 - 2 . 42 ( m , 4 H ) , 2 . 40 - 2 . 20 ( m , 4 H ) . LR - MS ( ESI ) m / z 531 ( M + 1 ) .