1 H NMR ( 400 MHz , CD 3 OD ) δ 8 . 17 ( t , J = 1 . 5 Hz , 1 H ) , 8 . 15 ( d , J = 2 . 2 Hz , 1 H ) , 7 . 99 - 7 . 92 ( m , 3 H ) , 7 . 79 - 7 . 73 ( m , 2 H ) , 7 . 66 ( dd , J = 7 . 5 , 1 . 8 Hz , 1 H ) , 7 . 53 ( t , J = 7 . 8 Hz , 1 H ) , 6 . 66 ( dd , J = 7 . 5 , 5 . 1 Hz , 1 H ) , 3 . 67 ( s , 2 H ) , 2 . 64 ( d , J = 45 . 5 Hz , 8 H ) , 2 . 43 ( s , 3 H ) . LR - MS ( ESI ) m / z 494 ( M + 1 ) .