1 H NMR ( 400 MHz , DMSO - d 6 ) δ 10 . 99 ( br s , 1 H ) , 9 . 78 ( s , 1 H ) , 8 . 27 ( d , J = 5 . 6 Hz , 1 H ) , 8 . 07 ( s , 1 H ) , 4 . 40 ( q , J = 7 . 2 Hz , 2 H ) , 2 . 19 ( s , 3 H ) , 1 . 35 ( t , J = 7 . 2 Hz , 3 H ) .