1 H NMR ( 400 MHz , DMSO - d 6 ) δ 8 . 88 ( t , J = 5 . 5 Hz , 1 H ) , 8 . 41 ( s , 1 H ) , 8 . 01 ( s , 1 H ) , 4 . 82 ( s , 1 H ) , 4 . 28 ( ddd , J = 49 . 3 , 9 . 4 , 2 . 0 Hz , 1 H ) , 3 . 84 - 3 . 63 ( m , 1 H ) , 3 . 40 - 3 . 22 ( m , 1 H ) , 1 . 13 ( d , J = 7 . 0 Hz , 6 H ) .