1 H NMR ( 400 MHz , DMSO - d 6 ) : δ [ ppm ] = 1 . 47 - 1 . 64 ( m , 3 H ) , 1 . 70 - 1 . 88 ( m , 2 H ) , 1 . 93 - 2 . 03 ( m , 1 H ) , 3 . 99 - 4 . 12 ( m , 2 H ) , 5 . 05 ( d , 1 H ) , 7 . 64 ( ddd , 1 H ) , 7 . 89 ( d , 2 H ) , 8 . 17 ( ddd , 1 H ) , 8 . 21 ( d , 2 H ) , 8 . 70 ( dd , 1 H ) , 8 . 74 ( s , 1 H ) , 8 . 92 ( d , 1 H ) , 9 . 66 ( d , 1 H ) .