1 H NMR ( 500 MHz , DMSO - d 6 ) δ 13 . 03 ( s br , 2 H ) , 8 . 00 ( s , 1 H ) , 7 . 42 ( dd , J = 8 . 5 , 7 . 5 Hz , 2 H ) , 7 . 22 ( d , J = 8 . 7 Hz , 2 H ) , 7 . 17 ( tt , J = 7 . 5 , 1 . 0 Hz , 1 H ) , 7 . 14 - 7 . 09 ( m , 4 H ) , 6 . 76 ( dd , J = 16 . 7 , 10 . 5 Hz , 1 H ) , 6 . 05 ( dd , J = 16 . 7 , 2 . 4 Hz , 1 H ) , 5 . 69 - 5 . 55 ( m , 4 H ) , 4 . 35 ( d , J = 12 . 2 Hz , 1 H ) , 3 . 99 ( d , J = 12 . 8 Hz , 1 H ) , 3 . 20 - 3 . 11 ( m , 4 H ) , 2 . 97 ( t , J = 12 . 3 Hz , 1 H ) , 2 . 57 ( t , J = 11 . 8 Hz , 1 H ) , 1 . 88 - 1 . 77 ( m , 1 H ) , 1 . 66 - 1 . 54 ( m , 2 H ) , 1 . 02 - 0 . 85 ( m , 2 H ) .