1 H NMR ( 400 MHz , DMSO - d 6 ) δ [ ppm ] = 3 . 48 ( ddd , 1 H ) , 3 . 70 - 3 . 79 ( m , 1 H ) , 4 . 16 - 4 . 29 ( m , 1 H ) , 6 . 66 ( d , 1 H ) , 7 . 52 ( d , 2 H ) , 7 . 64 ( dd , 1 H ) , 8 . 09 - 8 . 14 ( m , 2 H ) , 8 . 15 - 8 . 20 ( m , 1 H ) , 8 . 67 - 8 . 72 ( m , 2 H ) , 8 . 93 ( d , 1 H ) , 9 . 61 ( t , 1 H ) .