1 H NMR ( 400 MHz , DMSO - d 6 ) : δ [ ppm ] = 1 . 16 ( d , 3 H ) , 3 . 40 - 3 . 50 ( m , 2 H ) , 3 . 99 - 4 . 09 ( m , 1 H ) , 4 . 95 ( t , 1 H ) , 7 . 57 - 7 . 61 ( m , 2 H ) , 8 . 01 - 8 . 05 ( m , 2 H ) , 8 . 25 ( dt , 1 H ) , 8 . 67 ( s , 1 H ) , 8 . 76 ( d , 1 H ) , 8 . 85 ( t , 1 H ) , 9 . 34 ( d , 1 H ) .