1 H NMR ( 400 MHz , DMSO - d 6 ) : δ [ ppm ] = 3 . 66 - 3 . 74 ( m , 1 H ) , 3 . 79 - 3 . 86 ( m , 1 H ) , 4 . 81 - 4 . 92 ( m , 1 H ) , 5 . 45 ( br t , 1 H ) , 7 . 65 ( ddd , 1 H ) , 7 . 89 ( d , 2 H ) , 8 . 19 ( ddd , 1 H ) , 8 . 23 ( d , 2 H ) , 8 . 72 ( dd , 1 H ) , 8 . 80 ( s , 1 H ) , 8 . 93 ( d , 1 H ) , 9 . 96 ( d , 1 H ) .