1 H NMR ( 400 MHz , d 6 - DMSO ) δ 9 . 04 ( d , J = 7 . 2 Hz , 2 H ) , 7 . 75 ( d , J = 7 . 6 Hz , 2 H ) , 7 . 56 - 7 . 48 ( m , 2 H ) , 7 . 47 - 7 . 33 ( m , 3 H ) , 5 . 72 ( s , 2 H ) , 5 . 61 ( t , J = 8 . 0 Hz , 1 H ) , 3 . 42 - 3 . 37 ( m , 5 H ) , 2 . 70 - 2 . 58 ( m , 1 H ) , 2 . 17 - 2 . 00 ( m , 1 H )