1 H NMR ( 400 MHz , CD 3 OD ) δ 8 . 26 ( d , J = 2 . 2 Hz , 1 H ) , 8 . 15 ( d , J = 2 . 1 Hz , 1 H ) , 7 . 95 ( ddt , J = 18 . 6 , 12 . 3 , 6 . 0 Hz , 3 H ) , 7 . 76 ( d , J = 8 . 5 Hz , 1 H ) , 7 . 64 ( d , J = 8 . 5 Hz , 1 H ) , 7 . 52 ( dd , J = 8 . 3 , 2 . 8 Hz , 1 H ) , 3 . 72 ( s , 2 H ) , 2 . 83 ( m , 11 H ) . LR - MS ( ESI ) m / z 546 ( M + 1 ) .