1 H NMR ( 400 MHz , DMSO - d 6 ) δ [ ppm ] = 3 . 65 - 3 . 77 ( m , 1 H ) , 3 . 85 ( m , 1 H ) , 3 . 93 ( s , 3 H ) , 4 . 81 - 4 . 96 ( m , 1 H ) , 5 . 47 ( t , 1 H ) , 7 . 36 - 7 . 54 ( m , 2 H ) , 8 . 13 ( d , 1 H ) , 8 . 17 - 8 . 31 ( m , 2 H ) , 8 . 60 ( s , 1 H ) , 8 . 66 ( s , 1 H ) , 10 . 12 ( d , 1 H ) .