1 H NMR ( 400 MHz , DMSO ) δ 8 . 33 ( d , J = 2 . 9 Hz , 1 H ) , 8 . 06 ( d , J = 3 . 1 Hz , 1 H ) , 7 . 88 ( dd , J = 14 . 9 , 2 . 9 Hz , 1 H ) , 7 . 78 ( d , J = 2 . 9 Hz , 1 H ) , 7 . 65 - 7 . 52 ( m , 2 H ) , 7 . 30 ( dd , J = 8 . 9 , 7 . 4 Hz , 2 H ) , 6 . 89 ( s , 2 H ) , 3 . 54 ( s , 2 H ) , 2 . 50 ( ddd , J = 24 . 7 , 19 . 4 , 10 . 9 Hz , 4 H ) , 2 . 41 - 2 . 28 ( m , 4 H ) , 2 . 18 ( d , J = 30 . 1 Hz , 3 H ) , 1 . 86 - 1 . 52 ( m , 1 H ) , 1 . 39 - 0 . 82 ( m , 4 H ) . LR - MS ( ESI ) m / z 568 ( M + 1 ) .