1 H NMR ( 400 MHz , DMSO - d 6 ) δ 9 . 07 ( t , J = 5 . 6 Hz , 1 H ) , 7 . 95 ( s , 1 H ) , 7 . 74 ( t , J = 4 . 0 Hz , 3 H ) , 7 . 20 ( d , J = 4 . 0 Hz , 1 H ) , 4 . 93 - 4 . 89 ( m , 1 H ) , 4 . 24 ( t , J = 9 . 2 Hz , 1 H ) , 4 . 13 - 3 . 98 ( m , 2 H ) , 3 . 96 - 3 . 92 ( m , 1 H ) , 3 . 68 - 3 . 58 ( m , 2 H ) , 2 . 80 ( s , 3 H )