1 H NMR ( 400 MHz , DMSO - d 6 ) δ 10 . 65 ( s , 1 H ) , 8 . 60 ( s , 1 H ) , 8 . 03 ( d , J = 2 . 0 Hz , 1 H ) , 7 . 71 ( d , J = 1 . 6 Hz , 1 H ) , 7 . 58 ( d , J = 8 . 8 Hz , 1 H ) , 7 . 32 ( dd , J = 1 . 8 , 8 . 6 Hz , 1 H ) , 7 . 07 ( t , J = 9 . 2 Hz , 1 H ) , 6 . 99 ( dd , J = 0 . 8 , 2 . 0 Hz , 1 H ) , 6 . 89 ( dd , J = 2 . 8 , 6 . 4 Hz , 1 H ) , 6 . 49 ( m , 1 H ) .