1 H NMR ( 400 MHz , DMSO - d 6 ) δ [ ppm ] = 1 . 47 - 1 . 64 ( m , 3 H ) , 1 . 70 - 1 . 89 ( m , 2 H ) , 1 . 93 - 2 . 04 ( m , 1 H ) , 3 . 99 - 4 . 12 ( m , 2 H ) , 5 . 06 ( d , 1 H ) , 7 . 56 - 7 . 61 ( m , 2 H ) , 7 . 99 - 8 . 06 ( m , 2 H ) , 8 . 24 ( dt , 1 H ) , 8 . 68 ( s , 1 H ) , 8 . 76 ( d , 1 H ) , 8 . 85 ( t , 1 H ) , 9 . 62 ( d , 1 H ) .