1 H NMR ( 400 MHz , DMSO - d 6 ) δ [ ppm ] = 1 . 19 ( d , 3 H ) , 3 . 42 - 3 . 51 ( m , 2 H ) , 3 . 93 ( s , 3 H ) , 4 . 00 - 4 . 13 ( m , 1 H ) , 4 . 96 ( t , 1 H ) , 7 . 53 ( d , 2 H ) , 8 . 12 ( s , 1 H ) , 8 . 16 - 8 . 24 ( m , 2 H ) , 8 . 57 ( s , 1 H ) , 8 . 60 ( s , 1 H ) , 9 . 53 ( d , 1 H ) .