1 H NMR ( 400 MHz , CD 3 OD ) δ 8 . 26 ( dd , J = 6 . 7 , 2 . 3 Hz , 1 H ) , 8 . 14 ( d , J = 2 . 2 Hz , 1 H ) , 8 . 08 - 7 . 92 ( m , 3 H ) , 7 . 79 ( d , J = 8 . 5 Hz , 1 H ) , 7 . 71 ( dd , J = 7 . 5 , 1 . 8 Hz , 1 H ) , 7 . 38 ( t , J = 8 . 9 Hz , 1 H ) , 6 . 71 ( dd , J = 7 . 5 , 5 . 1 Hz , 1 H ) , 3 . 69 ( s , 2 H ) , 2 . 59 ( s , 8 H ) , 2 . 40 ( s , 3 H ) . LR - MS ( ESI ) m / z 512 ( M + 1 ) .