1 H - NMR ( DMSO - d 6 ) δ 8 . 96 ( t , 1 H - NH , J = 6 . 0 Hz ) , 8 . 51 ( s , 1 H ) , 8 . 25 ( d , 1 H , J = 8 . 0 Hz ) , 7 . 95 - 7 . 97 ( m , 1 H ) , 7 . 83 - 7 . 85 ( m , 1 H ) , 7 . 53 - 7 . 61 ( m , 2 H ) , 7 . 43 - 7 . 46 ( m , 2 H ) , 5 . 82 ( d , 1 H , J = 7 . 6 Hz ) , 5 . 56 ( d , 1 H , J = 6 . 4 Hz ) , 5 . 38 ( d , 1 H , J = 4 . 0 Hz ) , 5 . 12 ( d , 1 H , J = 6 . 0 Hz ) , 4 . 59 - 4 . 61 ( m , 1 H ) , 4 . 34 - 4 . 35 ( m , 1 H ) , 3 . 40 - 3 . 44 ( m , 1 H ) , 2 . 80 ( dd , 1 H , J = 2 . 4 , 6 . 8 Hz ) ;