1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 10 ( s , 1 H ) , 8 . 38 ( t , J = 2 . 9 Hz , 1 H ) , 8 . 05 ( d , J = 2 . 9 Hz , 1 H ) , 7 . 98 ( s , 1 H ) , 7 . 92 ( dt , J = 14 . 6 , 3 . 2 Hz , 1 H ) , 7 . 81 - 7 . 69 ( m , 2 H ) , 7 . 63 ( d , J = 14 . 7 Hz , 1 H ) , 7 . 59 - 7 . 47 ( m , 2 H ) , 7 . 36 ( d , J = 14 . 9 Hz , 1 H ) , 3 . 53 ( s , 2 H ) , 2 . 52 - 2 . 43 ( m , 4 H ) , 2 . 40 - 2 . 31 ( m , 4 H ) , 2 . 23 ( s , 2 H ) , 2 . 14 ( s , 3 H ) , 2 . 06 ( s , 3 H ) . LR - MS ( ESI ) m / z 551 ( M + 1 ) .