1 H NMR ( 600 MHz , DMSO - d 6 ) δ = 9 . 03 ( t , J = 6 Hz , 1 H ) , 7 . 71 ( d , J = 4 Hz , 1 H ) , 7 . 50 ( d , J = 9 Hz , 2 H ) , 7 . 33 ( d , J = 7 . 8 Hz , 2 H ) , 7 . 27 ( d , J = 7 . 8 Hz , 2 H ) , 7 . 20 ( d , J = 4 Hz , 1 H ) , 7 . 17 ( d , J = 9 Hz , 2 H ) , 4 . 86 - 4 . 78 ( m , 1 H ) , 4 . 33 ( t , J = 9 . 6 Hz , 2 H ) , 4 . 13 ( t , J = 9 Hz , 1 H ) , 4 . 05 ( t , J = 10 Hz , 2 H ) , 3 . 81 ( dd , J = 9 , 6 Hz , 1 H ) , 3 . 65 - 3 . 53 ( m , 2 H ) , 2 . 33 ( s , 3 H )