1 H NMR ( 400 MHz , CD 3 OD ) δ 8 . 14 ( d , J = 2 . 1 Hz , 1 H ) , 8 . 00 ( t , J = 1 . 4 Hz , 1 H ) , 8 . 00 - 7 . 92 ( m , 2 H ) , 7 . 75 ( d , J = 8 . 5 Hz , 1 H ) , 7 . 73 - 7 . 65 ( m , 2 H ) , 7 . 55 ( ddd , J = 8 . 9 , 2 . 5 , 1 . 3 Hz , 1 H ) , 6 . 66 ( dd , J = 7 . 5 , 5 . 1 Hz , 1 H ) , 3 . 68 ( s , 2 H ) , 2 . 67 ( d , J = 60 . 6 Hz , 8 H ) , 2 . 48 ( s , 3 H ) . LR - MS ( ESI ) m / z 512 ( M + 1 ) .