1 H NMR ( 400 MHz , DMSO - d 6 ) δ [ ppm ] = 3 . 65 - 3 . 74 ( m , 1 H ) , 3 . 82 ( dt , 1 H ) , 4 . 80 - 4 . 91 ( m , 1 H ) , 5 . 44 ( t , 1 H ) , 7 . 52 ( d , 2 H ) , 7 . 64 ( dd , 1 H ) , 8 . 10 - 8 . 16 ( m , 2 H ) , 8 . 16 - 8 . 21 ( m , 1 H ) , 8 . 71 ( dd , 1 H ) , 8 . 75 ( s , 1 H ) , 8 . 92 ( d , 1 H ) , 9 . 98 ( d , 1 H ) .