1 H NMR ( 400 MHz , DMSO - d 6 ) δ ppm = 3 . 13 - 3 . 30 ( m , 2 H ) , 3 . 67 ( s , 3 H ) , 3 . 71 - 3 . 77 ( m , 1 H ) , 7 . 20 - 7 . 25 ( m , 2 H ) , 7 . 31 ( t , 1 H ) , 7 . 81 ( d , 2 H ) , 11 . 27 ( s , 1 H ) .