1 H NMR ( 400 MHz , DMSO - d 6 ) δ 9 . 71 ( d , J = 2 . 7 Hz , 1 H ) , 8 . 03 ( d , J = 2 . 2 Hz , 1 H ) , 7 . 69 ( d , J = 1 . 8 Hz , 1 H ) , 7 . 61 ( dt , J = 8 . 5 , 0 . 9 Hz , 1 H ) , 7 . 34 ( dd , J = 8 . 5 , 1 . 8 Hz , 1 H ) , 7 . 00 ( dd , J = 2 . 2 , 1 . 0 Hz , 1 H ) , 2 . 79 ( t , J = 6 . 6 Hz , 2 H ) , 0 . 86 - 0 . 73 ( m , 1 H ) , 0 . 37 - 0 . 24 ( m , 2 H ) , 0 . 07 - 0 . 06 ( m , 2 H ) .