1 H NMR ( 400 MHz , DMSO - d 6 ) : δ [ ppm ] = 0 . 26 - 0 . 50 ( m , 4 H ) , 1 . 03 - 1 . 13 ( m , 1 H ) , 3 . 40 - 3 . 47 ( m , 1 H ) , 3 . 52 - 3 . 63 ( m , 2 H ) , 4 . 93 ( t , 1 H ) , 7 . 57 - 7 . 61 ( m , 2 H ) , 8 . 01 - 8 . 06 ( m , 2 H ) , 8 . 26 ( ddd , 1 H ) , 8 . 68 ( s , 1 H ) , 8 . 77 ( d , 1 H ) , 8 . 86 ( d , 1 H ) , 9 . 47 ( t , 1 H ) .