1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 49 ( s , 1 H ) , 8 . 39 ( s , 1 H ) , 8 . 06 ( s , 1 H ) , 7 . 97 ( s , 1 H ) , 7 . 69 ( d , J = 4 . 0 Hz , 2 H ) , 7 . 56 ( s , 1 H ) , 7 . 37 ( s , 1 H ) , 7 . 08 ( s , 1 H ) , 6 . 54 ( s , 1 H ) , 3 . 93 ( s , 3 H ) , 3 . 54 ( s , 2 H ) , 2 . 48 ( s , 4 H ) , 2 . 34 ( s , 4 H ) , 2 . 21 ( s , 2 H ) , 2 . 14 ( s , 3 H ) . LR - MS ( ESI ) m / z 524 ( M + 1 ) .