1 H NMR ( 400 MHz , DMSO - d 6 ) : δ [ ppm ] = 3 . 19 - 3 . 32 ( m , 2 H ) , 3 . 36 - 3 . 43 ( m , 1 H ) , 3 . 55 - 3 . 64 ( m , 2 H ) , 4 . 69 ( t , 1 H ) , 5 . 00 ( d , 1 H ) , 7 . 56 - 7 . 61 ( m , 2 H ) , 7 . 63 ( dd , 1 H ) , 8 . 01 ( d , 2 H ) , 8 . 14 - 8 . 19 ( m , 1 H ) , 8 . 67 ( s , 1 H ) , 8 . 69 ( br s , 1 H ) , 8 . 92 ( br s , 1 H ) , 9 . 51 ( t , 1 H ) .